ANAIS DOS TRABALHOS CIENTÍFICOS

Apoio

1

Amoxicillin associated with PLLA as an alternative to systemic antibiotics in Implantology

NISHIDA AC1,FRANCCI C1, CARNAVAL TG2, ADDE CA2

1Biomaterials and Oral Biology Department, School of Dentistry, University of São Paulo 2 Integrated Clinical Department, School of Dentistry, University of São Paulo

To evaluate the behavior of the association of Amoxycillin 20% to PLLA as a local alternative to periimplantar infections treatment 48 (N) polymer disks with 6mm were prepared in association with amoxicillin 20% according to the group: F (Film) and M (Membrane) by methods of deposition (Casting) and electrospinning (Nanofibers), respectively. All discs were stored in a buffer solution (pH 5 or 7.4) and aliquots were analyzed by high performance liquid chromatography (HPLC) on 8, 24, 48, 72, 96, 120, 144 and 168 hours. Specimens were weighed after 3 and 6 months for degradation analysis. For biocompatibility, fibroblast viability was tested by the MTT reaction after 24, 48 and 72 h. At pH 5, F peaked at 61% release after 144h, and M 50% after 24 hours of storage. At pH 7.4, F peaked at 52% release after 72h, and M 14% after 24 hours. The Kruskal-Wallis analysis demonstrated differences between M and F at pH 5 (p=0.03), at pH 7.4 (p=0.003) and between the different buffers (p<0.05). ANOVA analysis showed that F and M were biocompatible and similar (p> 0.05). As for degradation in pH 5.0 groups maintained 37% (F) and 61% (M) of mass (p> 0.05). But in pH 7.4 M were totally degraded after 3 months and F maintained 45% (p<0.05). Amoxicillin is promising for use in association with PLLA. The use of F presents greater release time in relation to M, but M presents a higher initial time release

Keywords: PLLA, Polymers, antibioticterapy

2

Evaluation of three antimicrobial agents incorporated into one-step self-etch adhesives

Cocco AR*1, Maske TT1, Peralta S1, Lund RG1, Moraes RR2.

1School of Dentistry, Federal University of Pelotas, RS 2School of Dental Materials, Federal University of Pelotas, RS

Abstract

In this study, three antimicrobial agents were tested: terpinen-4-ol (essential oil of Melaleuca alternifolia - Tr), silver microparticles (Ag) and zinc silicate (ZnSi). A 0.5% or 1% mass of the agents was added to an experimental one-step, self-etch adhesive (control - C: unmodified adhesive). The antimicrobial activity was assessed in a microcosm biofilm model (72h, intermittent regimen with 1% sucrose) using 70 bovine dentin discs (n=10). Counts (CFU/mg) of Total Microorganisms (TM), Total Acidurics (TA), Streptococcus mutans (Sm) and Total Lactobacilli (TL) were carried out. The other properties were: degree of C=C conversion (DC) by FTIR (n=3), microtensile bond strength (μTBS) to dentin (n=10), translucency parameters (TP) by color spectroscopy (n=5), and pH. For TL, 0.5% ZnSi and 1% Ag groups had greater antimicrobial activity than C. For TA, 0.5% Ag > C. For TM, 0.5% Ag and 0.5% ZnSi > C. For Sm, 0.5% ZnSi = C, and the other groups > C. For DC(%) there were no differences between groups, with means ± standard deviations ranging between 75.8±2.5 (C) and 65.9±2 9 (0.5%Tr). For μTBS (MPa), 1% ZnSi (34.6±10.7) and 1% Ag (31.5±3.6) were greater to C (32±6.9), while the other groups had similar μTBS than C. For TP, 1% Ag (55.1±4.5) was less translucent than the other groups. The pH ranged from 1.82 (1% ZnSi) to 1.29 (0.5% Tr). In conclusion, the group containing 1% ZnSi had better physical-mechanical properties and rendered antimicrobial potential to the adhesive.

Keywords

Anti-Bacterial agents, Adhesive, Dental materials

Funding

Support from Septodont Confi-Dental Division

3

Thermal stress effect in zirconia-veneer samples: finite element analysis Jikihara NA*1, Tanaka CB1, Meira JBC1.

1Departamento de Biomateriais e Biologia Oral, Faculdade de Odontologia, Universidade de São Paulo, SP.

Abstract

Thermal residual stresses (TRT) are listed as the main cause of chipping on veneered zirconia. The aim of this study was to

evaluate, by finite element analysis, the TRT generated during the porcelain cooling (600°C - 25°C) on specimens with different

geometries: disc, cylinder, “cup”, “cup with rim”, and crown. For which geometry, except for the crown, three porcelain

thicknesses were simulated (1, 2 e 3 mm and uniform zirconia core 0.7 mm). Maximum (σ1) and minimum (σ3) residual

principal stress distributions and peak in the porcelain layer were compared. Graphs of σ1 e σ3 along porcelain thickness in a

critical region were plotted. For the disc, a tensile peak on the outer surface (maximum σ1: 12 to 19 MPa, depending on

thickness) and a compressive peak at the interface (minimum σ3: -32 to -37 MPa) were observed. For other geometries, tensile

and compressive peak were found at the interface (maximum σ1: 10 to 36 MPa; minimum σ3: -29 to -36 MPa). On specimens

with curved interface, high tensile stress occurred at the porcelain concave curvature, while higher compression occurred at

convex curvature. Overall, the greater the porcelain thickness, higher values of σ1 and σ3. It was concluded that the disc-

shaped specimens showed a very different pattern of TRT from that found in a prosthetic crown. The curvature of porcelain at

the zirconia interface significantly influences the TRT, in which the porcelain with concave curves are more prone to chipping.

Keywords

Dental Porcelain, Dental Crowns, Finite Element Analysis

Funding

FAPESP N° 2013/06988-8; 2012/15910-0

4

Evaluation of IPS e.max CAD system in masking dental substrates Pimentel AH*1, Kodama AB1, Basso GR1,Kaizer MR1,Boscato N1, Della Bona A2, Moraes RR1

1School of Dentistry, Federal University of Pelotas, RS - Brazil 2School of Dentistry, University of Passo Fundo, RS - Brazil

Abstract

The aim of this study was to evaluate in vitrothe systemIPS e.maxCAD (lithium disilicate), in different thicknesses and opacities (HT and LT), regarding its translucency and masking ability in association with simulated dental substrates (shade A2 and C4). Specimens of different thicknesses (0.7, 1.0, 1.5 and 2.0mm) were evaluated individually and onto the substrates A2 and C4 (n = 10). Translucency parameter and influence of the substrate and specimen thickness on color variation of the ceramic laminate were measured with the spectrophotometer SP60 X- Rite (Grand Rapids - Michigan, USA), based on CIEL*a*b* system.The reductionin thickness of the e.max sample determined a significant increase in translucency. Color variation (ΔE) was higher for specimens HTthanLT, with both substrates. In general, the smaller the thickness the higher the ΔE values, regardless the substrate.The effect of the thickness is more critical for the C4 substrate than the A2 substrate. Considering substrate C4, samples HT from thicker to thinner showed ΔE values in between 9.58 and 15.59; while for LT samples the values varied from 8.16 to 13.03. On the other hand, with substrate A2, samples HT from thicker to thinner showed ΔE values in between 8.53 and 13.36; while for LT samples the values varied from 7.37 to 10.92. It was concluded that the reduction in thickness of the lithium disilicate layer and the background color C4 had the greatest influence on the final color of the ceramic laminates.

Keywords: Laminate veneers. Masking ability. Translucency.

5

Influence of the addition of 1,3,5-triacryloylhexahydro-1,3,5-triazine in the properties of an experimental orthodontic adhesive Altmann ASP*1, Collares FM1, Samuel SMW1.

1 Dental Materials Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, RS

Abstract

The development of antimicrobial adhesives aims the reduction of white spot lesions incidence in orthodontic patients without jeopardizing its properties. Triazine-containing compounds are known as effective antimicrobial agents. The aim of this study was to develop an experimental orthodontic adhesive containing methacrylated-triazine (1,3,5-triacryloylhexahydro-1,3,5-triazine) and evaluate its degree of conversion (DC) and solvent degradation (SD). The experimental adhesives were formulated by mixing 75% of BisGMA, 25% of TEGDMA, 0.1% of BHT and 5% of colloidal silica by weight; CQ, EDAB and DPIH were added to 1% mol. 1,3,5-Triacryloylhexahydro-1,3,5-triazine were added in three different concentrations 10%, 15% and 20%, in weight. The DC (n=3) of the 3 concentrations and the control group was measured using Fourier transform infrared spectroscopy (FTIR). The SD (n=3) was evaluated by Knoop microhardness from the specimens obtained from DC assay before and after immersion in ethanol for 2 hours. The addition of 15 and 20% of methacrylated-triazine showed a significant increase in DC (p<0.05) when compared to control group (0%) and 10% group. All groups showed a decrease in the hardness after ethanol immersion (p<0.001) and no significant difference was observed in the percentage of hardness variation among the groups (p=0.06). The addition of methacrylated-triazine in 15 and 20% increased the conversion degree of experimental orthodontic adhesives without compromising its strength to solvent degradation.

Keywords

adhesives; antibacterial; Orthodontics.

6

Study of cuspal deformation, fracture resistance and stress in molars with involvement endodontic restored with composite resin

Bicalho AA*1, Pereira RAS1, Ruggiero JG1, Tantbirojn D2, Versluis A3, Soares CJ4

1Department of Operative dentistry and dental Materials Dental School, Federal University of Uberlandia, MG, Brazil. 2DepartmentofOperativeDentistryand Dental Materials,DepartmentofRestorativeDentistry, CollegeofDentistry,Universityof Tennessee Health Science Center, Memphis, TN, USA.

3DepartmentofBioscienceResearch,CollegeofDentistry, Universityof Tennessee Health Science Center, Memphis, TN, USA.

Abstract

Restorative materials inserted into the pulp chamber may affect the biomechanical performance of direct restorations . The aim of this study was to evaluate the effect of restoring endodontically treated molars protocol in the cuspal (DC) , fracture strength ( RF ) and residual stresses . Forty-five human molars with MOD cavities were restored using 3 protocols : RC , resin in pulp chamber ( Filtek Z350XT , 3M - ESPE ) ; RMGI , modified glass ionomer resin in pulp chamber ( Vitremer , 3M - ESPE ) ; GI , conventional glass ionomer in the pulp chamber ( Ketac Fill, 3M - ESPE ) . DC buccal (V) and lingual (L) was measured for straingage and RF with axial compression test. Elastic modulus (E) and Vickers hardness (VHN) were obtained by dynamic indentation .Stress were analyzed by finite element analysis( FEA) for the modified von Mises criterion. Data from DC , E , VHN and RF were analyzed by ANOVA and Tukey's test ( P = 0.05 ) and FEA qualitatively.The CO values were: L - CR (54.1 ± 23.4 ); CR -V ( 30.9 ± 18.7); GI -L ( 22.2 ± 10.8 ); GI- V ( 18.8 ± 8.6 ); RMGI -L ( 36.8 ± 17.3 ); RMGI - V ( 23.2 ± 12.1 ). The RF values were: RC (943.7 ± 134.1 ); GI ( 1882.1 ± 444 ); RMGI ( 1502.8 ± 371.4 ). The values of E and VHN RMGI and GI groups were equal and smaller than RC in the pulp chamber. RC resulted in higher stresses in the enamel and root dentin. The use of conventional ionomer or resin modified glass in the pulp chamber benefits the biomechanical behavior of endodontically treated molars with composite resin.

Keywords

Composite Dental Resin, Glass Ionomer, Dental Stress Analysis

Funding

Fapemig, Capes, CNPq

7

Characterization and evaluation of dental implants surfaces avaliable in the brazilian market Bielemann AM*1, Silva RM2, Sarmento HR3, Faot F4.

1Graduate Student of Dental Prosthesis- Graduate Program in Dentistry, Federal University of Pelotas, RS 2Graduate Student of Science and Materials Engineering - Federal University of Pelotas, RS. 3PhD Student of Restorative Dentistry - Graduate Program in Dentistry - Federal University of Pelotas, RS 4Department of Restorative Dentistry, Faculty of Dentistry, Federal University of Pelotas, RS.

Abstract

This study characterized the surfaces of implants available in the Brazilian market considering its topography, chemical composition and roughness. The brands were selected according to their surfaces: Kopp (Ko), Signo Vinces (Sv) , Neodent (Ne) , OSSEOTITE (Os), NanoTite (Na) , SIN , Titanium Fix (Tf), conventional Straumann ( Str ), SLActive (SLA) . Morphological analysis was performed to characterize the surfaces and to check the contaminants by SEM-EDS. Parameters of surface roughness and 3D reconstructions were obtained by laser microscopy (20x). Two distinct regions were evaluated: i) cervical (does not receive surface treatment); ii) middle third (region with treated surface). The surface characterization by SEM showed morphological differences between all implants surfaces. EDS analysis showed predominance of elemental titanium (Ti ) for all implants. SLA showed only peaks of Ti while other surfaces showed traces of contaminants such as: Al, C, O, N , F , Mg , Na, Pr and Mr. To the surface roughness only Neo and Nn exceeded the average roughness values (Ra) of 0.5 to 1.0 μm exhibiting a minimally rough surface. Only Str and SLA showed Ra up to 2μm. It was concluded that there is no pre-established standard for morphology, chemical composition and roughness of implant surfaces that enables a secure comparison. National brands showed to be more sensitive to the techniques used for surface treatment.

Keywords

Dental Implants, Surface Properties, Energy Dispersive X-ray

8

Effect of low level laser in bone regeneration associated with bovine bone graft in rat calvaria.

Almeida ALPF*,1, Cunha MJS1, Esper LA1, Sbrana MC1, Soares S1, Neppelembroek KH1.

1 Departament of Prosthodontics, Bauru School of Dentistry, University of São Paulo, SP

Abstract

The aim of this study was to evaluated histologically the effect of low level laser ( LLL ) on the healing of critical-size defects ( CSD ) in rat calvaria , filled with autogenous or inorganic bovine bone grafts. Sixty rats were divided into 6 groups (n = 10) :

C (control - filled with blood clot ), LLL ( Low Level Laser - GaAlAs , 780nm , 100mW , 210J/cm2 , ɸ 0.05 cm2 , 6J/ponto), OA (Autogenous Bone), OAL (Autogenous Bone + Low Lavel Laser), BO (Inorganic Bovine Bone) , BOL (Inorganic Bovine Bone + Low Level Laser ). The animals were euthanized after 30 days. Histological and histometric analysis was performed with a light microscope. The groups irradiated with low level laser, LLL (47.67 % ± 8.66 %), OAL (39.15% ± 16.72%) and BOL (48.57 % ± 28.22%) showed a larger area bone formation than the C group (9.96 % ± 4.50%), OA (30.98% ± 16.59 %) and BO (11.36 % ± 7.89 % that were not irradiated . Moreover, were significantly better than Group C - Kruskal - Wallis, followed by Dunn's test (p <0,05 . Based on the methodology employed can be concluded that the laser accelerated the healing of bone defects and resorption of particles of graft materials.

Keywords

Lasers. Bone Transplantation, Bone Regeneration

Funding

FAPESP Process nº 2010 /13170-3 e 2010/10538-0.

9

Dentin surface treatment using a non-thermal argon plasma brush: Influence on roughness and bond strenght.

Ayres APA*1, Bonvent JJ2, Nascimento FD3,Lopes BB4, Ambrosano GMB1, Giannini M1

Insert affiliation here 1Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas, SP. 2 Natural and HumanitiesSciences Center, Federal University of ABC, SP. 3Biomaterials Research Group, AnhangueraUniversity, SP. 4Surface - Engineering and PlasmaSolution LTDA, SP.

Abstract

Thisstudy investigated the effect ofplasma applicationon surface roughness and dentin bond strenght(BS) to dentin of ScotchbondUniversal(3M ESPE), usingself-etchapproach. The argon plasma (Plasma Tool Model SAP, Surface) was applied for 10 and 30 s. The surface roughness of dentin treated with plasma were analyzed by Atomic Force Microscopy (AFM) and the obtained data were compared with untreated dentin group (control group). For BS test, 24 third human molars previously extracted were divided into 3 groups (n = 8): control (untreated), plasma for 10s, plasma for 30s. The teeth had deep dentin exposed and abraded for 10 s with SiC 600 paper to standardize the smear layer (control group) and the plasma was applied in the experimental groups. Afterwards the adhesive was applied and a composite block of Filtek Z350 XT (3M ESPE) with 6 mm in height was built on dentin. The teeth were stored at 37oC for 24 hours and sectioned perpendicular to the interface area with diamond blade in order to obtain specimens with a cross section area of approximately 1 mm2 for the microtensile test. Data were analyzed by one-way ANOVA (5%). AFMimagessuggested an increase insurface roughnessfor 30 s plasma treated group.This treatment also increased BS, while 10 s of plasma application showed no significant difference in BS when compared to control group. The results suggested that 30 s plasma treatment resulted in morphological changes of dentin surface and increased BS for self-etch approach.

Keywords

Plasma Gases; Dentin; Adhesives

Funding

FAPESP # 2013/15952-7

10

Influence of resin luting agent’s shade on optical properties of ceramic laminates. Perroni AP*1, Amaral C1, Kaizer MR¹, Moraes RR¹, Boscato N¹.

1School of Dentistry, Federal University of Pelotas, RS

Abstract

The aim of this study was to evaluate the masking ability and translucency of Vita VM7 ceramic specimens; in monolayer, with 1 mm of thickness (enamel-E1 and dentin-D1), and bylayer, with 0.5 mm each (enamel and dentin- E0.5D0.5), overlaying discs simulating dental substrates (shades: A2 and B1) and discs of luting agent (Revolution Formula 2) (shades: A1, A2, B1, WO and IL), n=10. Translucency parameter (TP) and influence of the substrate, luting agent shade and ceramic specimens on color variation (ΔE) of the laminates were measured with a spectrophotometer Vita Easyshade (Vita Zahnfabrik/Bad Saeckingen, Germany), according to the CIEL*a*b* system. E1 ceramic specimens presented the higher values of TP and D1 the lower, when overlying or not the luting agent. All ceramic groups showed the higher TP values for IL and the higher values of opacity for WO luting agent shade. The L* values usually were higher for B1 substrate and E1 ceramic group. The a* and b* parameters and ΔE values were higher when measured on A2 substrate. It was concluded that the WO and IL luting agent shades, ceramic group E1 and substrate A2 had more influence on the final color of the ceramic laminates.

Keywords

Veneer, Dental; Cements, Dental; Esthetics, Dental

11

Cytotoxicity of 4-(N,N-dimethylamino)phenethyl alcohol on photo-polymerized experimental dental composite resins Costa AR*, Oliveira DCRS, Silva CB, Muniz BV, Volpato MC, Sinhoreti MAC

*Department of Restorative Dentistry, Dental Materials Division, Piracicaba Dental School, State University of Campinas – UNICAMP, SP.

Abstract

The aim of this study was to evaluate the cytotoxicity of experimental dental composite resins (ECR) with 4-(N,N-

dimethylamino)phenethyl alcohol (DMPOH)associated to the camphorquinone (CQ) photoinitiator system as reducing agent,

compared to ethylamine benzoate (EDAB). The ECR was produced blending 35 wt% of an organic matrix (29 wt% Bis-GMA,

32.5 wt% UDMA, 32.5 wt% Bis-EMA, 6 wt% TEGDMA) and 65 wt% of filler content (52 wt% 0.7μm BaBSiO2 and 13 wt% 0.04μm

fumed sílica). 0.4 wt% of photoinitiator system was used mixing 0.2 wt% of CQ and 0.2 wt% of one of the reducing agents

tested (DMPOH or EDAB). 5x1 mm polymerized samples (n=5) of each resin were previous submitted to degree of conversion

(DC%) measurement and then, pre-immersed in Dulbeco’s modified medium for 24 h. Epithelial cells were cultured to evaluate

the cytotoxic effects after 1 h and 24 h using the microtiter-tetrazolium (MTT) method. Data were submitted to Kruskal-Wallis

(α=0.05). No significant differences were found among the DC% of CQ/DMPOH and CQ/EDAB samples. 1 h outcomes showed

no significant difference between CQ and EDAB: 99.26% (7.3), CQ/DMPOH: 94.85% (4.2) and the control group (CG). After 24 h

no significant difference were found between CQ/EDAB: 48.44 % (3.3) and CQ/DMPOH: 38.06 % (17.0), but significant

difference compared to the CG (p>0.05). DMPOH as EDAB induced cell viability reduction after 24 h of exposition; no

significant differences were observed for the cytotoxicity between EDAB and DMPOH reducing agents used on dental

composite resins in association with CQ photoinitiator systems.

Keywords

Polymer, Fourier Transform Infrared Spectroscopy, cell survival.

12

Effects of energy densityof curing light on bonding of fiber posts to root canals Szesz AL*1, Cuadros-Sanchez JL¹, Hass V¹, Cruz GK², Arrais CAG³, Reis A³, Loguercio AD³

¹ Graduate students.Department of Restorative Dentistry, School of Dentistry, State University of Ponta Grossa, PR, Brazil.

² Professors.Department of Phisics.School of Phisics, State University of Ponta Grossa, PR, Brazil.

³Professors.Department of Restorative Dentistry.School of Dentistry, State University of Ponta Grossa, PR, Brazil.

Abstract

This study evaluated the effect of different energy densities delivered to two simplified etch-and-rinse adhesive systems on push-out bond strength (PBS) of fiber posts to root canal, as well as nanoleakage (NL) and in situ degree of conversion (DC) within the hybrid layer. The roots of human premolars were endodontically prepared and divided into six groups [according to the combination of the main factors Adhesive/resin cement (2 commercial brands) and Energy density (4, 16, 48 and 288 J/cm2)]. The posts were cemented and the PBS tested at 0.5 mm/min (n=7). The NL (n=3) was evaluated using Scanning Electron Microscopy (SEM) after immersion of specimens in 50% silver nitrate. Micro-Raman spectroscopy was performed to determine the in situ DC (n=2). Data were analyzed by three-way repeated measures ANOVA and Tukey post-hoc tests (5%). PBS (MPa) showed a significant difference only for the middle third when an increase in energy density from 4 to 16 J/cm² or higher was used (p < 0.05). The NL (%) decreased significantly with increasing energy density from 48 to 288 J/cm² in the middle and apical when compared to lower energy density (p < 0.05). The energy density of 288 J/cm² significantly increased DC (%) in the middle and apical thirds compared the other energy densities (p < 0.05). The increase in energy density delivered to the cervical third of root canals during post cementation improved adhesive performance of simplified etch-and-rinse adhesive systems at the apical and medium thirds.

Keywords: Push-out bond strength, fiber posts, root dentin

13

Preliminary results for color changes of ceramic veneers cemented with photocuring and dual luting agent: randomized clinical trial

Marchionatti AME*1, Wandscher VF 1, Bottino MA2, May LG1

Insert affiliation here 1Department of Restorative Dentistry, School of Dentistry, Federal University of Santa Maria, RS. 2Department of Dental Materials and Prosthodontics, São José dos Campos Dental School, São Paulo State University, SP.

Abstract

The aim of the study was to evaluate color change of ultra-thin ceramic veneers cemented with photocuring and dual resin cement by means of a split-mouth clinical trial. Ceramic laminates (0.3 mm thick) at 0.5 mm from the gingival margin were cemented to the buccal surface of the second premolars of 10 participants with transparent shade of Variolink II (Ivoclar Vivadent), one side by photoactivation and the opposite side by dual activation, randomly. Participants were blind for the activation mode. Color visual evaluation was performed with a color scale Vita 3D-Master (Vita Zahnfabrik). Instrumental evaluation by CIE L*a*b* system was performed with a clinical spectrophotometer Vita Easyshade (Vita Zahnfabrik) 24 hours and 6 months after cementation. Cement marginal discoloration was also evaluated. Color change (ΔE) was calculated and paired sample t test did not show statistical difference between the groups. Photocuring group mean was 2.68 (±0.69) and dual group mean was 2.46 (±0.69). Considering visual evaluation, there was no alteration for the parameters value, hue and chroma. Marginal discoloration was not observed. Longer follow-up results are necessary in order to determine if the two curing modes of Variolink II can be used for ceramic veneer cementation.

Keywords

Dental Veneers, Resin Cements, Color

14

Clinical assessment of the periodontal index of patients affected by non-carious cervical lesions.

Pereira, A.G.*, Teixeira, D.N.R., Montes T.C., Zeola L.F., Machado A.C., Silva M.B., Soares P.V.

School of Dentistry, Federal University of Uberlandia, MG

Abstract

The study aimed to analyze the periodontal indexes of thepatientsfrom extension program ( LCNC - HD ) carried by The Group of Teaching, Research and Extension in Non-CariousCervical Lesions and Dentin Hypersensitivity from the School of Dentistry, UFU. 42 patients were treated and catalogedfrom Dec/2012 to Apr/2014. The parameters evaluated were: PPB - presence of plaque; SS - bleeding on probing; and PS – pocket depth greater than 3 mm; CRI/CRII- recessionclassificationin Millerclass I or II, respectively. The distribution of parameters observed among the groups of teeth was: gingival recession - RG; RG/LCNC- recession associated with non - carious cervical lesion; DMD – mesio-distal dimension of RGs; DCA - cervical- apical dimension of RGs. The results for the distribution of PPB, SS, PS and CRI / CRII, were: PPB - 42.8%; SS- 28.6%; PS- 28.6%; CRI/CRII- 80% / 20%respectively.Regarding the distribution of RG and RG/LCNC, in the groups of teeth was, respectively: upper molars 31.6% and 12%; premolars 14% and 21.7%; incisors and canines 8.8% and 12%; lower molars 15% and 12%; premolars 12.3% and 22.9%; incisors and canines 17.5% and 19.3%. For DMD the results were: 9.1% (0 -2mm); 59.1 % (2 - 4mm); 18.2% (4 -6mm); 13.6% (6- 8mm). For DCA theresults were: 56.8% (0 -2mm); 39.4% (2 - 4mm); 3.8%(4 -6mm); 0% (6 -8mm). Despite showing low rates of bacterial periodontal disease, gingivitis and periodontitis patients affected by NCCLs exhibit high rates of damageto the periodontal structures of protection and support.

Keywords

Tooth wear, Periodontal index, Occlusion

Funding

Siex/UFU 10893

15

Biological properties of a new periodontal dressing. Conceição LD1, Dutra AL2*, Lund RG3, Piva E4, Ogliari F5, Leite FRM6.

1School of Dentistry, Federal University of Pelotas, RS 2School of Dentistry, Federal University of Pelotas, RS 3School of Dentistry, Federal University of Pelotas, RS 4School of Dentistry, Federal University of Pelotas, RS 5School of Materials Engineering, Federal University of Pelotas, RS 6School of Dentistry, Federal University of Pelotas, RS

Abstract

The aim of this study was to develop a periodontal dressing (PD) based on methacrylate monomers (Exothane™-Gexp) and characterize the biological response comparing with Periobond™ (Gperio) and Barricaid™ (Gbar) (controls). Citotoxicity and Genotoxicity specimens products were diluted in Dulbecco’s modified Eagle’s medium (DMEM) for 24h, 72h and 7 days. Tests were performed in a cell lineage of mouse fibroblasts 3T3/NIH in triplicate. For citotoxicity the survival of cells was measured photometrically using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Genotoxicity was indicated by micronuclei (MN) formation next to nucleus and was analyzed by light microscopy (400x). Microbiological test was performed with inoculum strains of E. faecalis and S. mutans. The samples were plated on TSA and MSA for analysis of Colony Forming Units (CFU). The statistical analysis was performed by ANOVA and Tukey/Kruskall-Wallis (P<0.05). The cytotoxic effects were time dependent. At 24h difference was found between Gexp and Gperio. At 72h, no differences were seen between Gexp and Gbar but were positive between both and Gperio (P<0.001). At 7 days, difference was observed between Gbar and Gperio (P=0.04). In genotoxicity test no difference was found among the groups. In microbiological assay, no statistical difference was found for E. faecalis and for total microorganisms. We conclude that material made with Exothane had similar behavior to the commercial products and can be possibly used as a periodontal dressing.

Keywords

Periodontal dressings. Dental materials. Elastomers

16

Evaluation of three types of experimental orthodontic cement. Goicochea AM*1, Heming VM1, Ogliari AO1, Ogliari FA2, Moraes RR1.

1School of Dentistry, Federal University of Pelotas, RS 2School of Materials Engineering, Federal University of Pelotas, Pelotas, RS

Resumo

The aim of this study was evaluation three types of a experimental orthodontic cement (EC). The conventional type (ECC), self-etching (ECSE) and an unpublished, self-adhesive (ECSA), of EC were formulated. As a commercial control, were used Transbond XT and Transbond SEP (3M Unitek). The materials were characterized for shear bond strength (BS), flexural strength (FS) and degree of conversion (DC). For BS were used bovine incisors (n=15) and metal bracketes, whic were cemented and photoactivated in two times of 20s each. For the FS, were prepared (n=15) specimens measuring 2x10x10mm. For both tests, the materials were stored in distilled water at 37 º C for 24h and tested. The Adhesive Remnant Index (ARI) score was classified under magnification (20 ×). The GC was evaluated by infrared spectrophotometer, where the samples (n = 5) were analyzed in two times, immediately after deposition and curing 20s. Quantitative data were subjected to one-way ANOVA and Tukey test (5%). The results for the tests of BS and FS showed that Transbond XT showed the highest values of both BS, FS as compared to other cements. The DC of the experimental cements CEC, ECSE, ECSA were statistically similar, and all were higher than Transbond XT. Prevalence of ARI scores 0, 1 and 2 were observed in the groups. The experimental orthodontic cements show satisfactory and promising results when compared to conventional.

Descritores

Orthodontics, Dental cement

Apoio

CNPq

17

Different concentrations of hydrofluoric acid: impact on the roughness and flexural strength of a feldspathic ceramic

Venturini AB*1, Prochnow C1, May LG1, Bottino MC2, Valandro LF1.

. 1Department of Restorative Dentistry,School of Dentistry, Federal University of Santa Maria, RS 2Department of Restorative Dentistry (Division of Dental Biomaterials),School of Dentistry, Indiana University, IN, USA

Abstract

The aim of the study wasto examine the impact of different concentrations of hydrofluoric acid (HF) on the roughness and flexural strength of a feldspathic ceramic.A hundred and fifty bar-shaped specimens (14x4x1.2mm) were fabricated from ceramic blocks (VitaBlocks Mark II). All specimens were polished, chamfered and sonically cleaned in isopropyl alcohol. Specimens were randomly divided into five groups (n=30): SC (control) - no ceramic surface treatment; HF1, HF3, HF5 and HF10 were etched for 60 s with different concentrations of hydrofluoric acid: 1%, 3%, 5% and 10%, respectively. All specimens were analyzed in a rugosimeter and subjected to 3-point bending test. Data were analyzed using one-way ANOVA and Tukey’s test (α=0.05). Weibull module (m) and characteristic stress (σ0) were also determined. All groups produced significantly rougher surfaces than the control group (SC) (p<0.05). The mean values of flexural strength of conditioned groups were statistically similar (106.47 to 102.02MPa), and below of the untreated group. HF etching had a weakening effect on the porcelain. The different hydrofluoric acids affected the flexural strength in a similar way.

Keywords

Hydrofluoric acid, glass ceramics, CAD-CAM.

18

Bond strength of self-adhesive resin cement as repair materialfor composite resin

Silva AV*1, Munchow EA1, Valente LL1, Isolan CP1, Moraes RR1.

1School of Dentistry, Federal University of Pelotas, RS.

Abstract

This study evaluated the effectiveness of a self-adhesive resin cement (SARC - RelyX U200, 3M ESPE) on the repair of composite resin (CR). Fifteen CR blocks (Filtek Z250, 3M ESPE) were thermalcycled using 2.000 cycles, embedded in acrylic resin, and polished with 600- and 1200-grit SiC abrasive papers. The blocks were assigned into five groups (n=20) according to the surface treatment protocol performed before cement application: Control (C, no treatment); roughening with #3168F diamond bur (RDB); silanization (S – Prosil, FGM), etching with hydrofluoric acid (HF – CondacPorcelana, FGM), or roughening as aforementioned + silanization (RDB+S). A silicone mold with four orifices (diameter 1.5 mm) was placed over the specimens and the orifices were filled with cement. Specimens were stored in distilled water at 37°C for 24h and then submitted to shear bond strength (SBS) test and failure mode analysis. Data was analyzed by one-way ANOVA and Tukey’s test (p<0.05). SBS means (standard deviations) were: C= 14.1 (7.9)B; RDB= 21.4 (8.5)A; S= 17.1 (7.7)AB; HF= 11.6 (6.1)B; and RDB+S= 22.1 (6.7)A. Adhesive failures were predominant for all groups. It can be concluded that for the repair of CR restorations with SARC, previous surface roughening may improve the repair bond strength.

Keywords

Resin cements. Shear Strength. Composite resins.

19

Evaluation of methods used to measure color change in clinical study of tooth whitening.

Santos NA1*, Oliveira-Neto LA1, Correia ACC1, Santana TR1, Nahsan FPS1, Faria-e-Silva AL1

1 School of Dentistry, Federal University of Sergipe, Aracaju, Sergipe, Brazil

Abstract

This study evaluated methods of shademeasurement used for in-office tooth bleaching clinical trial. Twenty-six patients were submitted to t two sessions of in-office bleaching using a single-application of 35% hydrogen peroxide with a week of interval. The shade of six upper anterior teeth was measured previous to first session, using a spectrophotometer (l, a and b values),Vita Classical (VC) and Bleachguide (BG) scales, while the average ofshade measured in these six teeth were used to analysis. For use of scales, the selected shade was scored in 1 (lightest) to 16 or 15 (darker), for VC and BG scales respectively .Shade measurement was repeated 7 days after each bleaching session, while ΔE (for CIElab data) and change of scores for each scales were calculated. Data were submitted to Wilcoxon and Spearman correlation statistical tests (α = 0.05). There was no difference in bleaching effect between the two sessions when the VC scale (P = 0.086 )was used or ΔE (P = 0.223 was calculated. In opposite, the first session resulted in higher bleaching effect than the second (P < 0.001) when BG was used. The VC scale showed significant correlation with ΔE (R = 0.56, P < 0.001) and BG (R = 0.28, P = 0.04), while this last was weaker. There was no significant correlation between BG and ΔE data (R = 0.21, P = 0.13). It can be concluded that the method used for shade evaluation in clinical assessment of bleaching procedures can have significant effect on the results.

Keywords

Hydrogen peroxide.Tooth Bleaching.

20

Relationship between filler content and selected mechanical properties of six microhybrid composites.

Wingert A*, Mota EG, Nogarett LM, Oshima HMS, Souza EC, Spohr AM.

Department of Dental Materials, School of Dentistry, PUCRS.

Abstract

The purpose of this study was evaluate the influence of filler weight content on selected mechanical

properties of six microhybrid composite resins. Compressive strength, elastic modulus, vickers

microhardness (VHN), and weight filler content were evaluated in six different dental composites: Admira

(AD), Charisma (CH), InTen-S (IN), Tetric Ceram (TC), Point 4 (P4), and Z250 (Z2). Mean values for

compressive strength (MPa) ranged from P4 76.60 to Z2 222.33. Elastic modulus (GPa) from IN 2.56 to

Z2 4.59. VHN from P4 50.53 to Z2 87.88. Filler weight content (Wt%) from IN 72.51 to TC 79.56.

Significant differences were found between the composites on the different tests (ANOVA/Tukey, p<0.05).

Z2 had the highest compressive strength; Z2 and TC showed the highest elastic modulus, VHN and filler

weight content. Weight filler content have a strong influence in mechanical properties (0.78<R2<0.98,

p<0.01).

Keywords

Dental materials, composites, strength of materials.

21

Evaluation of IPS e.max CAD system in masking metallic cores Kodama AB*1, Pimentel AH1, Basso GR1, Kaizer MR1, Boscato N1, Della Bona A2, Moraes RR1

1School of Dentistry, Federal University of Pelotas, RS - Brazil 2School of Dentistry, University of Passo Fundo, RS - Brazil

Abstract

The aim of this study was to evaluate in vitro the masking ability and translucency of IPS e.max CAD ceramic specimens (lithium disilicate glass-ceramic), in two opacities (HT and LT), and different thicknesses (0.7; 1.0; 1.5; 2.0 mm), overlaying silver and cooper discs that simulated metal cores (n=10). Translucency parameter and influence of the substrate and ceramic specimen thickness on color variation of the laminate were measured with a spectrophotometer SP60 X-Rite (Grand Rapid – Michigan, USA), according to the CIEL*a*b* system. The reduction in thickness of the e.max samples was determinant in the increase in translucency. Color variation (ΔE) with the metallic substrate was higher for the HT specimens. For both HT and LT the smaller the thickness the higher the ΔE values, regardless the substrate. The effect of the thickness is more critical for the silver substrate than the cooper substrate. Considering substrate silver, samples HT from thicker to thinner showed ΔE values in between 18.75 and 33.72; while for LT samples the values varied from 13.83 to 27.68. On the other hand, with substrate cooper, samples HT from thicker to thinner showed ΔE values in between 17.28 and 30.98; while for LT samples the values varied from 13.12 to 25.60. It was concluded that reduction in thickness of the lithium disilicate layer and the silver substrate had higher influence on the final color of the ceramic laminates.

Descritores

Keyword: Color. Dental ceramics. Masking ability.

22

Amoxicillin loaded microspheres incorporated in experimental adhesive resins

Prunes BB1*, Genari B1, Leitune VCB1, Collares FM1, Samuel SMW1, Jornada DS2, Guterres SS2.

1. Dental Materials Laboratory, School of Dentistry, Federal University of Rio Grande doSul, Porto Alegre, Brazil.

2. Micro-and Nanoparticles Applied Therapeutics Laboratory, School of Pharmacy, Federal University of Rio Grande doSul, Porto Alegre, Brazil.

The aim of this study was to develop an experimental adhesive resin incorporating amoxicillin loaded microspheres and to evaluate its properties. The resin was formulated with 66%Big-GMA and 33%HEMA in weight.

Camphoroquinone, EDAB at 1% in mol, and BHT at 0,01% in weight were added as polymerization photoinitiators. Amoxicillin loaded microspheres, produced by solubilization of the components and dried by atomization, were

incorporated to the adhesive resin in the 1%, 2% and 5% concentrations in weight, as well as a control group without their addition. The microspheres were characterized by MEV and laser diffraction. The immediate and late

degree of conversion was evaluated by FTIR-ATR. The softening in solvent was evaluated through initial Knoopmicrohardness and afterwards through ethanol imersion for 2 hours. Statistical analysis was performed

using ANOVA, Tukey's test and paired t-test at the 0.05 level of significance.The microspheres present an average diameter of 4.198µm. As to the degree of conversion assay, the resin with the addition of 1% of microspheres did not present any differences when compared to the control group, with a variation of 61.32 to 34.40. As to the

softening in solvent assay, all groups presented a reduction in microhardness after the imersion in ethanol. There was no difference in the percentage of degradation in the group with the addition of 1% of microspheres and the

control group. We conclude that the incorporation of 1% of amoxicillinloaded microspheres can be an alternative for adhesives with therapeutic action.

Keywords:microspheres, dentine-bonding agents, amoxicillin

Funding:

FAPERGS

23

Nanoencapsulated indomethacin in dental adhesives

Genari B1*, Garcia IM1, Jornada DS2, Leitune VCB1, Collares FM1,Pohlmann AR2, Guterres SS2, Samuel SMW1.

1Laboratory of Dental Materials, School of Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.

2 Laboratoty of Micro and Nanoparticles Applied in Therapeutics,FacultyofFarmacy, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.

Abstract

The objective of the study was to develop a dental adhesive with nanocapsules (NC) containing indomethacin and evaluate its properties. The NCwere produced by deposition of preformed polymer and the formulation was dried. The NC were characterized by scanning electron microscopy, particle size, Fourier transform infrared spectroscopy and Raman spectroscopy. The formulation of the adhesive resin was obtained by mixing, in weight, 50% of Bis-GMA, 25% of TEGDMA and 25% of HEMA. As photoinitiators, 1% in mol of camphoroquinone, EDAB anddiphenyliodonium, besides 0.01%, in weight, of BHT were added. The NC were added to the resin in concentrations of 1, 2, 5 e 10%, and a group was maintained without NC. The adhesives were evaluated in relation to degree of conversion (DC, n=5) immediately and after four months of storage, degradationin solvent (n=5) and bond strength (n=20). The data were analyzed by ANOVA, Tukey and t test at the 0.05 level of significance. The NC, in suspension, presented medium diameter of 165 nm and4.58 µm after drying.The NC did not alter the DC, presenting immediate values from 67.21 to 70.01. The DC did not decrease after the storage time, presenting values between 68.39 and 71.68. The percentage of degradation in solvent of the groups with NC did not present difference comparing to group without NC, varyingfrom 37.79 to 57.5. The bond strength did not present differences between the groups. Based on these results, it is possible to conclude the adhesives with encapsulated indomethacin have potential to present therapeutic action associated with adhesion.

Keywords

Dental adhesive. Nanocapsules. Indomethacin.

24

Stress analysis in endodontically-treated teeth restored with crowns and pins using

finite element.

Hirata BS*1, Borges AL2, Costa AKF2, Lima AL2, Guiraldo RD1, Lopes MB1, Tango RN2, Gonini-Júnior A1.

1School ofDentistry, Universityof North of Paraná, PR. 2SchoolofDentistry, Paulista StateUniversity Júlio de Mesquita Filho – São José dos Campos, SP

Abstract

The provisional restorations of endodontically-treated teeth ( PRE ) supported by pins is a common feature in indirect restorative process by molten metallic cores . This study evaluated the stress distribution at PRE restored with full temporary crown inside the canal sustained by metal pins . The digital model of endodontically treated tooth 21 and their support structures are defined by setting five groups ( G). G1 (control ) - delimited if the temporary crown in acrylic resin to total peripheral preparation. In G2 - simulated roots were prepared, considering the temporary restoration supported by canal pin stainless steel orthodontic wire ( 1 mm diameter) , while in G3 was used prefabricated brass pin . In G4 , G5 , similar to G2 and G3 , reduced the thickness of the remaining walls . We considered the elastic moduli and Poisson's ratios of the structures to determine the Von Misses stress in Ansys software loading models with load of 100N at 45 ° in the incisal edge of the tooth. As for the values of maximum stress ( MPa ) , an increase of 2.5 % from G2 to G4 and G3 55.50% for G5 . This result suggests that brass pins with the decrease in the amount of remaining dentin would increase the stress concentration in tooth structure. It is concluded that regardless of the amount of dentine , the stainless steel pins yield better dissipation of the tensions in the remaining dentine structure.

Keywords

Metal pin, finite element analysis, non-vital tooth, temporary restoration

25

Effect of misfit and prosthetic abutments on strain induced in overdenture – retaining

system casted in Ti cp and in loosening torque of prosthetic screw

Zen BM*, Anacleto FN, Nunez-Pantoja JMC, Ribeiro RF, Barão VAR, Consani RLX, Mesquita MF

Insert affiliation here

Piracicaba Dental School, University of Campinas, SP

Abstract

The aim of this study was to analyze the mean of vertical misfit (VM) of overdentures bars casted in Ti cp; measure the strain (S) and loosening torque (LT) of prosthetic screws, in passive and non-passive frameworks. Twenty bars were casted with Ti cp. The misfit quantification followed the protocol of single-screw test. The misfit was standardized by interposing a metal ring of 200 µm between pilar A. The measurements of strain were made by strain gauges fixed in the replicas. The loosening torque of prosthetic screws was evaluated using a digital torque meter. Statistical difference (α = 0.05) was found between passive and non-passive groups: percentage of (LT) (UCLA, p = 0.0087; MA, p < 0.0001); mean S (MA, p = 0.0192) independently of passivity and between the non-passive bars (p = 0.0001), regardless the abutment used. Pearson's correlation indicated a positive correlation between VM x LT (UCLA, r = 0.6503; MA, r = 0.7338); LT x S for UCLA (r = 0.5373) and VM x S (r = 0.5678). It can be concluded: the prosthetic screws have a higher tendency for loosening in non-passive prostheses; non-passive frameworks induce higher levels of strain and vertical misfit compared with passive frameworks; UCLA abutments showed the better results in non-passive prostheses; strain, vertical misfit and loosening torque were correlated factors.

Keywords

Implant, titanium, fit

Funding

FAPESP (Sao Paulo Research Foundation) (2011/15512-1 and 2012/05708-9)

.

26

Application of hydrophobic coatings on pmma-based resin

Duarte CG*1,Silva MF1, Valente LL1, Moraes RR1.

1School of Dentistry, Federal University of Pelotas, RS.

Abstract

This study investigated the effect of application of hydrophobic coatings on the wettability of a thermo-polymerizable (poly)methylmethacrylate resin (PMMA, VIPI WAVE). Two hydrophobic solutions (HS) were tested: HS1 was obtained by dilution of 2.5 mass% of hexadecyl- triethoxy-silane in ethanol, while HS2 was defined by dilution of 2.5 mass% of perfluorodecyl-triethoxy-silane in dimethyl sulfoxide. A total of 30 PMMA discs (diameter 10 mm, thickness 2 mm) were prepared and allocated in three groups according to the surface treatment: C (control) – no coating; HS1 – coating with HS1 solution; and HS2 – coating with HS2 solution. A siloxane layer was deposited on PMMA by heat treatment at 150oC for 1h. Groups were separated in sandblasting (Sb) or non-sandblasting (NSb) application before coating. Water contact angle (θ, o) formed on surfaces was analyzed before or after coating (n=5). Data were analyzed by two-way ANOVA and Student-Newman-Keuls’ test (p<0.05). Means (standard deviations) for θ were: C-SB= 88.7 (8.3); C-NSb= 61.1 (4.7); HS1-Sb= 114.7 (3.8); HS1-NSb= 95.2 (6.8); HS2-Sb= 106.9 (2.6); and HS2-NSb= 106.4 (4.2). The effect of sandblasting was dependent on the HS applied. Sandblasted groups showed higher θ than non-sandblasted groups (P≤0.001). In conclusion, both hydrophobic coatings tested were able to improve wettability of PMMA, particularly HS1 associated with previous surface sandblasting.

Keywords

Acrylic Resins. Surface properties. Hydrophobia.

27

Effect of the addition of an iodonium salt and tertiary amine in the degree of

conversion, cohesive strength and cytotoxicity in an experimental adhesive.

Ferrúa CP*1, Leal FB1, Ogliari FA1, Gazal MO2, de Carvalho RV1,Ghisleni GC2, Demarco FF1, Nedel F1,2.

1School of Dentistry, Federal University of Pelotas, RS. 2Postgraduate Program in Health and Behavior, Catholic University of Pelotas, Pelotas, RS, Brazil.

Abstract

The study aimed to evaluate the degree of conversion (DC), the cohesive strength (CS) and cytotoxicity of an experimental adhesive system containing photoinitiator, tertiary amine and/or iodonium salt. Five initiator systems were investigated: canforaquinona (CQ); CQ and difeniliodônium (DPI); CQ and ethyl 4-dimethylamino benzoate (EDAB); CQ+EDAB+DPI in two concentrations. The DC was evaluated in infrared spectroscopy (FTIR-ATR) and the CS with specimens stored for 24h, both using 10 and 20s of photoactivation. In the cytotoxicity assay the mouse fibroblast cell line (NIH/3T3) were used and exposed to the respective eludates, which were formulated using specimens photoactivated for 10 and 20s, and immersed in cell culture medium for 1, 3, 5 and 7 days. Cell viability was accessed using the MTT. Data were analyzed by Kruskal-Wallis, Holm-Sidak and Tukey test (p < 0.05). The photoativation time statistically affected the DC, being higher in all groups evaluated after 20s. After 10s the presence of DPI increased the DC, G1<G3<G2<G4=G5. The presence of DPI also increased CS after 10s. Further, the groups containing DPI showed a minor cytotoxicity when compared with the control group G3<G2=G4=G5. There were no statistical differences in regard to the incubation and polymerization time. We concluded that the presence of DPI increases the reactivity of the photoinitiated system, the DC and the quality of the polymer formed after 10s of photoactivation, however it presented a slight cytotoxicity when compared with the control group.

Keywords

Dental adhesive; DPI; Camphorquinone; Cytotoxicity

28

Evaluation of mechanical properties of resin cements polymerized under different

ceramic systems

Lopes CCA*1, Rodrigues RB1, Bicalho AA1, Faria-e-Silva AL3, Soares PV1, Simamoto-Júnior PC2, Soares CJ1, Novais VR1

1Department of Operative Dentistry and Dental Materials, Dental School, Federal University of Uberlândia, MG 2Department of Fixed Prosthodontics and Dental Materials, Dental School, Federal University of Uberlândia. MG 3Department of Dentistry, Health and Biological Sciences Center, Federal University of Sergipe, SE

Abstract

This work aimed to evaluate the Vickers hardness (HV) and the modulus of elasticity (E) of resin cements polymerized under ceramic systems. Four resin cements were evaluated (n = 5): self-curing resin cement-Multilink (Mu); and three dual resin cements - Variolink II (Va), Allcem (Ac) and RelyX U200 (Ru); photoactivated after 5 minutes for 120 seconds, under three types of ceramic - feldspathic, reinforced with lithium dissilicate and reinforced by zirconia. As control, the cement was polymerized without ceramic bulkhead. After 12 hours, dynamic indentation test was conducted for calculation of HV and E of the cements. Data was analyzed by 2-way ANOVA/Tukey (α = 0.05). For HV, there was significance to the cement, ceramic factor (p < 0.001) and cement x ceramic interaction (p = 0.045). Já para E, there was significance to cement factor, however, the ceramic factor (p = 0.287) and cement x ceramic interaction (p = 0.259) were not significant. The Pearson correlation between HV and E presented coefficient r = 0.804, indicating high correlation, directly proportional, and significant (p < 0.001). It was concluded that the cement Mu presented minors values of HV regardless of the type of ceramic brought, since it is a chemical cement and does not depend on the light to polymerize. Between the dual cements, the Va has always the lowest HV. For E, dual cements showed no significant differences in mean values and all resulted in significantly higher values than the Mu, regardless of the type of ceramic.

Keywords

Resin cements, hardness, elasticity

Funding

CNPq

29 Effect of the incorporation of different percentages of inorganic filler in an experimental composite on its mechanical properties

Camila S. Sampaio1*, Eduardo José Souza-Junior1, Eduardo Ozera1, William Cunha Brandt2, Gislaine Cristina Padovani1, Mário Alexandre Coelho Sinhoreti1, Regina Maria Puppin-Rontani1

1 Piracicaba Dental School, State University of Campinas – UNICAMP, Brazil, 2University of Taubate – UNITAU, Brazil

The aim of this study was to evaluate the surface roughness (SR) and tensile strength (TS) of experimental

composites with different percentages of inorganic fillers. Experimental composites containing BisGMA,

BisEMA, UDMA and TEGDMA as organic matrix and camphoroquinone/amine as initiators were prepared.

Concerning the inorganic fillers, 4 different composites were analyzed: only glass fillers Ba-Al-SiO3 (C1), glass

fillers Ba-Al-SiO3 /SiO2 (90:10) (C2), glass fillers Ba-Al-SiO3 /SiO2 (80:20) (C3) and glass fillers Ba-Al-SiO3/SiO2

(70:30) (C4). After the preparation of the composites, for measuring the RS, cylindrical specimens (5mm in

diameter and 2mm thick, n = 4) were prepared. The specimens were irradiated using a LED Radii-cal for 40s.

After 24 h, RS was measured with a rugosimeter. For tensile strength, hourglass-shaped specimens were

fabricated (1mm2 cross section) and pulled in a universal testing machine (0.5mm/min). The results were

subjected to one-way ANOVA and Tukey's test considering a significance level of 5%. For the SR measurement,

all composites showed similar values (C1 - 0.400 ± 0.225, C2 - 0.640 ± 0.455; C3 - 0.332 ± 0.313; C4 - 0.585 ±

0.403). However, when evaluating TS, the experimental composite containing only glass particles showed

lower values compared to C2, C3 and C4 groups containing colloidal silica. The content of colloidal silica

increased the tensile strength, but showed no influence on the surface roughness of methacrylate based

experimental composites.

30

Effect of luting agents and post system on the stress distribution of ceramic crowns

submitted to tensile simulation test

Silva CF*1, Queiroz CL2, Martins VM3 , Veríssimo C4, Noritomi PY5, Santos Filho PC6

1,2,3,4,6School of Dentistry,Department of Dentistry and Dental Materials, University of Uberlândia, MG 5 Information Technology Center, Ministry of Science and Technology.

Abstract

The aim of this study was to evaluate the effect of different luting agents and posts on the stress distribution of ceramic crowns (CC) submitted to tensile tests by means of 3D finite element analysis (FEA). A simplified crown was generated with a tensile device placed on incisal surface on the incisal edge of the model. Twelve models were generated according to the restorative techniques as follows: glass fiber post (Gfp), cast post and core (Cp, Rely X ARC (ARC), Rely X Unicem (Unicem) and zinc phosphate (ZP) all restored with ceramic crown (Cc). The models were exported to FEA software to perform the mechanical properties insertion, and boundary conditions appliance. The results were evaluated by using Maximum Principal Stress. In CP models, there was stress concentration, but thestress concentrated priority in the crown. For all luting agent, there was higher tensile stress concentration in incisal interface between crown and core and cervical interface between crown and dentin root. ARC presented lower tensile stress concentration in these regions than Unicem and Z and it was similar stress distribution in models with FGP. Moreover, the models with FGP presented similar stress distribution. The tensile stress concentration was more visible in incisal interface between crown and core and cervical interface between crown and dentin root for CPC models, according to all luting agents. Keywords

Dental pins, Finite Element Analysis, Dental Cements

Funding

Fapemig Source: APQ-02312-12

31

Effect of the addition of an iodonium salt and tertiary amine in the degree of

conversion, cohesive strength and cytotoxicity in an experimental adhesive.

Ferrúa CP*1, Leal FB1, Ogliari FA1, Gazal MO2, de Carvalho RV1,Ghisleni GC2, Demarco FF1, Nedel F1,2.

1School of Dentistry, Federal University of Pelotas, RS. 2Postgraduate Program in Health and Behavior, Catholic University of Pelotas, Pelotas, RS, Brazil.

Abstract

The study aimed to evaluate the degree of conversion (DC), the cohesive strength (CS) and cytotoxicity of an experimental adhesive system containing photoinitiator, tertiary amine and/or iodonium salt. Five initiator systems were investigated: canforaquinona (CQ); CQ and difeniliodônium (DPI); CQ and ethyl 4-dimethylamino benzoate (EDAB); CQ+EDAB+DPI in two concentrations. The DC was evaluated in infrared spectroscopy (FTIR-ATR) and the CS with specimens stored for 24h, both using 10 and 20s of photoactivation. In the cytotoxicity assay the mouse fibroblast cell line (NIH/3T3) were used and exposed to the respective eludates, which were formulated using specimens photoactivated for 10 and 20s, and immersed in cell culture medium for 1, 3, 5 and 7 days. Cell viability was accessed using the MTT. Data were analyzed by Kruskal-Wallis, Holm-Sidak and Tukey test (p < 0.05). The photoativation time statistically affected the DC, being higher in all groups evaluated after 20s. After 10s the presence of DPI increased the DC, G1<G3<G2<G4=G5. The presence of DPI also increased CS after 10s. Further, the groups containing DPI showed a minor cytotoxicity when compared with the control group G3<G2=G4=G5. There were no statistical differences in regard to the incubation and polymerization time. We concluded that the presence of DPI increases the reactivity of the photoinitiated system, the DC and the quality of the polymer formed after 10s of photoactivation, however it presented a slight cytotoxicity when compared with the control group.

Keywords

Dental adhesive; DPI; Camphorquinone; Cytotoxicity

32

Mechanical properties comparison of resin cemet self-adhesive

Almeida CM*1, Meereis CTW1, Leal FB1, Ogliari AO1, Ogliari FA2..

1School of Dentistry, Federal University of Pelotas, RS 2School of Materials Engineering, Federal University of Pelotas, Pelotas, RS

Resumo

The aim of this study was evaluation the mechanical properties of resin cements self adhesives (SARC) comparing with the SARC experimental (SARCE) included dentin bond strength (TBS), flexural strength (FS), elastic modulus (E). Five commercial SARCs are evaluation (CRA (SmartCem 2 - Dentisply; BisCem - Bisco; SeT PP - SDI; Relyx U100 - 3M ESPE), and one SARCE. For the bond strength was used bovine incisors (n=10) that were worn to expose dentin. The matrix with cilindrical holes was positioned and filled with cement and photoactivated for 20s. The specimens was stored in destilled water at 37ºC for 24h and 6 months and after done the TBS test. The data was submitted for ANOVA two way and Holm Sidak test (p<0.05). For FS and E was build rectangular specimes (n=10), stored in destilled water at 37ºC for 24h, and tested FS. The data of FS and E was analysed for ANOVA one way and Holm Sidak test (p<0.05). The TBS evaluation, in MPa, after 24 hours of Bis Cem (3.0 ± 0.8) were significantly smallest than the others SARCs. However after 6 months only U100 (11.6 ± 4.2) and Set PP (4.2 ± 1.6) maintained the TBS values; and the SARCE (5.5 ± 2.0) were significantly similar than the Set PP. The FS data in (MPa) and E in (GPa), respectively of SARCE (84.1 ± 16.1)(2.7 ± 0.6) was similar to U100 (77.4 ± 11.8 )(2.5 ± 0.4) and Smart Cem (76.7 ± 12.0)(2.2 ± 0.3) and the higher SeT PP (56.6 ± 11.5) (1.2 ± 0.3) and BisCem (37,9 ± 4,3) (1,8 ± 0,3). The U100, Set PP and SARCE presented highest TBS values after 6 months and the SARCs U100, Smart Cem e o SARCE experimental showed better results as RF and E.

Descritores

Dental cement; dentin; modulus

Apoio

FAPERGS

33

Evaluation of the color stability of composite resin after storage in red wine

Pieper CM*1, Porto JAS1, Münchow EA1, Piva E1, Pereira-Cenci T1, Cenci MS1

1School of Dentistry, Federal University of Pelotas, RS

This study investigated the color stability of a composite resin (Filtek Z-350, 3M ESPE) after storage in red wine. Forteen disk-shaped specimens (6 mm in diameter x 2 mm in thickness) were prepared and allocated in two groups according to the storage medium (n=7): red wine (???) and distilled water (control). The color of specimens was measured with a digital spectrophotometer (Easyshade) using the CIEL*a*b* color parameters, and it was measured immediately after surface polishing (baseline) and after 24h, 7 days, 2 and 3 months of storage in the solutions. The color difference (ΔE*) data were analyzed with two way repeated measures ANOVA and Tukey’s test (p<0.05). There was a significant interaction between the solutions and the period of storage (p=0.003). The ΔE* means during the storage periods were: 0.5B (24h), 1.3AB (7 days), 2.3A (2 months) e 0.5B (3 months) for specimens stored in water; and 7.4AB (24h), 5.8B (7 days), 9.1A (2 months) e 3.3C (3 months) for specimens stored in red wine. The wine produced higher ΔE* of the composite when compared to water (p<0.001). The ΔE* mean (standard deviation) between the final and baseline measurements was: 2.5 (1.0) for specimens stored in water and 19.5 (5.0) for specimens stored in wine. The composite resin evaluated showed color stability when stored in water, but the storage in wine significantly modified the material’s color, decreasing the intensity after 2 months of storage.

Keywords

Color, Composite resins, Pigmentation.

34

Flexural strength and probability of survival of zirconia block´s controlled production

Ramos CM*1, Bonfante EA2, Cesar PF3, Rubo JH2, Fortulan CA4, Borges AFS1

1Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, SP, Brazil. 2Department of Prosthodontics, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil. 3Department of Biomaterials and Oral Biology, Faculty of Dentistry, University of São Paulo, São Paulo, SP, Brazil. 4Department of Mechanical Engineering, School of Engineering of São Carlos, University of São Paulo, São Carlos, SP, Brazil.

Abstract

Evaluate the effect of controlling the production of Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) block´s on their flexural strength and probability of survival. The groups were 1)ZPC: Zirconia with controlled production, 2)ZCA: Zirconcad, 3)ZMAX: IPS e.max ZirCAD and 4)ZYZ: In Ceram YZ. The ZPC zirconia was developed from the powder of zirconium oxide with 3%mol yttrium oxide. The preparation of ceramic powder was performed manually and with control of all stages: mixing, solvent evaporation, granulation, isostatic pressing and pre-sintering. After the production of ZPC blocks, 30 rectangular specimens (2.4 mm x 4.8 mm x 19.2 mm) were constructed for each group (n=30), sintered and subjected to the test of three point bending with a speed of 0, 5mm/min according to ISO 6872. The flexural strength data were subjected to one-way ANOVA (α = 0.05). To analyze the probability of survival (500N load), the statistical Weibull analysis was used. Flexural strength (σf) and characteristic strength (σ0) of ZCP groups showed similar values to ZMAX and ZYZ. ZCA had the lowest values with difference for the other groups. For the Weibull modulus parameter (m) there was no difference among groups. To probability of survival in 500N, ZCA shows 85% with difference for ZCP (98%), ZMAX (100%) and ZYZ (99%). The control of the production of zirconia ZCP had a positive effect on their flexural strength and probability of survival.

Keywords

Ceramic; Zirconium; Survival Analysis

Funding

São Paulo State Research Foundation – FAPESP (#2011/18061-0)

35

The effect of immediate polishing with different systems on the roughness, hardness

and microleakage of a silorane composite

Pereira CNB*1, Lins FCR1, Silveira RR1, Ferreira RC2, Moreira NA1, Magalhães CS1

1Restorative Dentistry Department, 2Social and Preventive Dentistry Department, School of Dentistry, Federal University of

Minas Gerais, MG.

Abstract

This study evaluated the effect of immediate polishing with different systems on surface roughness, hardness and

microleakage of a silorane-based composite. Specimens were made (Filtek P90, 3M ESPE) in random order, according to the

following treatments: control (polyester strip), Sof – Lex discs (3M ESPE), Astropol (Ivoclar Vivadent) and Enhance

(Dentsply). The half of the specimens received immediate polishing and the others after 7 days. The surface roughness (Ra,

µm) (n = 20) and Vickers microhardness (n = 10) were measured. Cavities were prepared in bovine incisors and restored

with Filtek P90/SAS (3M ESPE). The restorations received the treatments described above (n = 10), were subjected to dye

penetration test (basic fuchsin 0.5 %, 24 h) and classified by microleakage scores. Data were analyzed by ANOVA and

Scheffé, Kruskal-Wallis and Mann-Whitney tests (p<0.05). For roughness and microhardness, there was a significant effect

of polishing systems (p<0.0001). The polishing time was not significant (p=0.5). In enamel, the microleakage was not

affected by the polishing system (p=0.309); postponed polishing produced higher scores (p=0.009). In dentin, Sof-lex and

Astropol showed microleakage scores higher than Enhance (p=0.033); the polishing time was not significant (p=0.313). It

was concluded that the immediate polishing did not influence the surface roughness, microhardness and microleakage of a

silorane–based composite. Sof-lex discs produced higher microhardness but higher microleakage in the dentin margins.

Keywords

Silorane resins, dental polishing, hardness test

Funding

FAPEMIG (CDS-APQ-01545-13), CAPES, PRPq/UFMG and CPGO/FOUFMG

36

Evaluation of surface texture adhesive composites before and after toothbrush

abrasion

Malavasi CV*¹; Rego GF1; Viana-de-Pinho MG1; Macedo E; Schneider LF1,2; Cavalcante LM1

1School of Dentistry, Federal Fluminense University, RJ 2 School of Dentistry, Veiga de Almeida University, RJ

Abstract

The aim of this study was to evaluate surface texture by means of the surface roughness and gloss retention of two self-adhesive composite with low viscosity and one nanoparticulate composite before and after toothbrushing abrasion tests. The composite Vertise Flow (Kerr) Fusio Liquid (Jeneric Pentron) and Filtek Z350 (3MESPE) were divided into 3 groups (n = 5). It was made disc of 12 mm diameter and 2 mm thick. All materials were light-cured with a LED light source for 40 seconds. Analysis of surface roughness and brightness were performed 24 hours after light curing and again after 20,000 brushing cycles. The results were submitted to ANOVA on 2 factors. The three composites showed high brightness changes after abrasion, with a reduction of 92% for Vertise flow, 84% for Fusio Liquid and 53% for Filtek Z350. Regarding the roughness values, no statistical difference was observed before the abrasion to any evaluated material. After abrasion Vertise Flow showed higher roughness, followed by Fusio Liquid and Filtek Z350. Although self-adhesive composite can generate a reduction in time as well as the clinical sensitivity of the technique, these materials showed the greatest change in the surface texture after abrasion compared to conventional nanoparticulate composite.

Keywords

Cosmetic Dentistry, Nanotechnology, Composite Resins

Funding

Agency of Innovation in Graduate Studies and Innovation of the Federal Fluminense University

37

Influence of ultrasonic agitation of the cleaning agent on the quality of fiber post

cementation.

Scotti CK*1, Fernandes SL1, Andreatta LM1, Zens MA1, Bombonatti JFS1, Mondelli RFL, Francisconi PAS1, Duarte MAH.

1Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, SP.

Abstract

This study evaluated the influence of ultrasonic agitation of the cleaning agent on the quality of fiber post cementation. To conduct the study 20 bovine incisors were prepared with roots Reciproc 50.05 instrument and filled. Roots were prepared with specific drill taper for the fiber post and were used in 2/ 3 of the length (10mm). The roots were randomly divided into two groups (n = 10). For the pre-etching cleaning the agent QMix 2 in 1 (DENTSPLY) was used, it was ultrasonically activated in group 1 (G1) for 1 minute and maintained for another 4 minutes into the root canal and in group 2 (G2) passively maintained for 5 minutes. The agents were removed and the conducts were irrigated with 3 ml of serum. The conducts were conditioned with 37% phosphoric acid gel for 15 seconds and washed with 3 ml of serum. The adhesive with fluorescein was applied and light cured for 20s. Silane was applied at post (WhitePost/FGM) and dual-curing resin cement containing fluorescein were prepared (AllCem/FGM) and photoactivated for 20 minutes. Were selected 4 slices of 1mm thickness and analyzed in confocal laser scanning microscopy to verify penetration of adhesive and cement. The push-out was performed on an Instron universal testing machine. There was a greater penetration of adhesive G2 for the cervical third and there was no statistical difference between groups for the push-out. Ultrasonic agitation did not affect the quality of fiber post cementation.

Key-words

Post and Core Technique. Ultrasonics. Cementation.

Support

FGM – Dental Products

38

Different concentrations of hydrofluoric acid: effect on the contact angle and resin

bond strength durability to a feldspathic ceramic

Prochnow C*1, Venturini AB1, Rambo DR2, Gundel A3, Valandro LF4

1Master’s Degree Student, School of Dentistry, Federal University of Santa Maria, RS 2Dentist, School of Dentistry, Federal University of Santa Maria, RS 3Professor, Federal University of Pampas, RS 4Associate Professor, Department of Restorative Dentistry (Prosthodontics), School of Dentistry, Federal University of Santa Maria, RS

Abstract

This study evaluated the effect of different concentrations of hydrofluoric acid (HF) in the contact angle and the

durability of bond strength between feldspathic ceramic and resin cement. For the contact angle analysis, 25

ceramic specimens (12x10x2.4mm) (VitaBlocks Mark II) were divided into 5 groups (n=5): SC (control) – no

treatment, and etching for 60s with hydrofluoric acid - 1% (HF1), 3% (HF3), 5% (HF5) and 10% (HF10). The contact

angle measurements were performed using a Goniometer. For bond strength evaluations, 40 ceramic blocks

(12x10x4mm) were subjected to the same surface treatments, excluding the SC group. After conditioning, the

blocks were silanized and resin cement was applied on the treated surface. The blocks were sectioned to produce

specimens for microtensile (1 mm2), which were divided into into two conditions (dry and aged). SC had the highest

contact angle (61.4°), whereas HF10 showed the lowest value (17.5°). In dry conditions, different acids promoted

statistically similar bond strengths (14.2 to 15.7MPa) (p<0.05); however, after aging, the bond of the HF1 group

decreased statistically (14.5 to 10.2MPa). In terms of adhesion, the tested ceramic can be etched by 3%, 5% or 10%

hydrofluoric acid. Topographic changes promoted by 3%, 5% and 10% acids seem to be enough for improving the

resin bond to feldspathic ceramic.

Keywords

Hydrofluoric acid, glass ceramics, tensile strength.

39

Reestablishment of the proximal contact in direct composite resin restorations

Gré CP*1 , Stolf SC1, Becker MM1, Araújo E1

1School of Dentistry, Federal University of Santa Catarina

The study evaluated the influence of matrix and wedge systems in reestablishing the proximal contact in restorations in

posterior teeth. After identically MO-preparation, teeth were divided in six groups (n=20). G1 e G2: sectional metal

matrix with separation rings (Dentsply). G3 e G4: metallic circumferential pre-contoured matrix bands in a Tofflemire

Senior retainer (KerrHawe) applied with contact former instrument (LM). G5 e G6: metallic circumferential pre-

contoured matrix bands in a Tofflemire Senior retainer (KerrHawe) applied with separation rings. Plastic (Danville) and

wooden wedge systems (Hawe Neos Dental) were used alternately in all groups. Cavities were restored using Adper

Single Bond 2 and Filtek Z250 (3M ESPE). Tightness of proximal contact was measured using Tooth Pressure Meter,

measurement of mesio-distal diameter and subjective evaluation. Results were analyzed using Kruskal-Wallis, ANOVA,

Qui-Square Tests. Bonferroni test indicated that the maximal frictional force for G1 (3,98N) and G2 (3,39N) resulted in

tighter contacts compared to G3 (1,54N), G4 (1,49N), G5 (1,85N) and G6 (2,04N) (p<0.05). Mesio-distal diameter was

statistically different for G1 (12,41mm) and G2 (12,37mm) compared to G3 (12,28mm), G4 (12,27mm), G5 (12,29mm)

and G6 (12,29mm) (p ≤ 0,05). In subjective analysis G1 and G2 resulted in the best contacts. No significant difference

was found among the other groups and among the selected wedges. The use of sectional pre-contoured metal matrices

combined with separation rings resulted in tighter proximal contacts.

Keywords: Composite resin restoration. Permanent Dental Restoration. Dental materials.

40

Formulation of experimental self-etch adhesives and bonding to caries-affected

dentin

Isolan CP*1, Maske TT1, Schwantz JK1, Cenci MS1, Moraes RR1 Indicate last names followed by authors’ initials (no periods between initials) using commas to separate authors. The presenting

1School of Dentistry, Federal University of Pelotas, RS

Abstract

This study evaluated the shear bond strength (SBS) of experimental self-etch adhesives containing three different

concentrations of the acidic monomer GDMA-P to sound dentin (SD) and caries-affected dentin (CAD). Microcosm

biofilms were formed over dentin discs and cultivated under anaerobic conditions for 14 days. A biofilm model was

used with intermittent availability of 1% sucrose in a culture medium for 4h daily. Six groups were defined by

different GDMA-P concentrations (5%, 20%, and 35%) and dentin type. Bovine dentin discs for each group (n=10)

were included in acrylic resin and the adhesives were applied. An elastomer mold with cylindrical orifices (1.5 mm

diameter) was used to obtain two cylinders of composite resin on the surface. After 24h the cylinders were

subjected to SBS test in a mechanical testing machine. Data were analysed by ANOVA and Student-Neuman-Keuls’

test (5%). Failure modes were observed under magnification. SBS results were statistically different between

substrates. Means ± standard deviations (MPa) were: 5.62 ± 1.90ABa(SD-5%), 3.81 ± 1.46Bb (CAD-5%), 4.82 ± 2.3Ba

(SD-20%), 5.91 ± 1.55Ab (CAD-20%), 6.41 ± 1.91Aa (SD-35%), and 3.52 ± 1.3Bb (CAD-35%). Adhesive failures were

predominant. In conclusion, acidic monomer concentration and dentin type significantly affected the bond

strengths.

Keywords

Adhesive, dental caries, shear strength

41

Evaluation of light transmission through fiber posts

Dias DA*1, Penelas AG1, Cavalcanti GH2, Guimarães JGA1.

1Analitical Laboratory of Restorative Biomaterials – LABiom-R, School of Dentistry, Federal Fluminense University, Niterói, Rio de Janeiro, Brazil. 2School of Physics, Federal Fluminense University, Niterói, Rio de Janeiro, Brazil.

Abstract

This study analyzed the light transmitting ability of various types and sizes of fiber posts. Seventeen experimental groups were formed, each one comprising a different kind of fiber post (n=3): WhitePost DC (WP)0.5, WP1, WP2, WP3, Exacto Translúcido (ET)0.5, ET1, ET2 and ET3, Reforpost Fibra de Vidro (RV)1, RV2 and RV3; Reforpost Fibra de Carbono (RC)1, RC2 and RC3; and Macro-Lock lllusion-X-RO (MI)1, MI2 and MI3. For light transmission analysis, the posts were transfixed to an opaque polyethylene disks, leaving only 10mm of its apical region free for measurements. The cervical portion of the post was irradiated (800mW/cm2), and light transmission was measured by a spectrometer, recording the amount of photons on the 450-490nm interval. Data were submitted to two-away ANOVA and Tukey’s multicomparison test (α=0.05). No light transmission was registered for RC and RV groups. In general, within each post system, the largest post presented superior transmittance values. The scattering analysis showed a decrease in the values from the cervical to the apical third for the WP and ET groups; the MI groups revealed the lowest values, which were similar in all portions; the scattering light values recorded at the posts apical third were quite low. Thus, carbon and glass fiber serrated posts are opaque. Smooth glass fiber posts seem to conduct light better than the serrated quartz post tested. For the fiber glass posts tested, the higher the diameter, the better the light transmission and scattering. Keywords

Fiber posts; Light transmission, Light scattering

Funding

42

Cytotoxicity, antibacterial effect and mechanical performance of temporary materials of dental prosthesis

Oliveira DJF*1, Oliveira HL2, Torre EN2, Peralta SL2, Etges A3, Lund RG3, Piva E3

1Undergraduate Student, Dental School, Federal University of Pelotas 2Ph D(c), Post-graduate Program in Dentistry, Dental School, Federal University of Pelotas 3Professor, Department of Operative Dentistry, School of Dentistry, Federal University of Pelotas

Abstract

The aim of this study was to evaluate the cytotoxicity (CT), biofilm accumulation test (BAT), flexural strength (FS), elasticity modulus (EM) and surface roughness (Ra). The materials tested were: Access crown (AC), Duralay (D), Protemp TM IV (P), Revotek LC (RLc) and Systemp C&B II (S). For the CT evaluation human keratinocytes (HaCat) were used, and was evaluated by MTT colorimetric assay using a spectrophotometer. The eluate was collected after the specimens were immersed in RPMI culture medium for 24 and 48 h. For the BAT, specimens were placed into 24-well plates and a 2 ml volume of BHI supplemented with 10% sucrose and 20 μL of S. mutans UA159 were inoculated into each well. After incubation at 37º C for 72 h in an anaerobic chamber, it was determined the number of viable bacteria. The FS and EM were obtained by a three-point bending test. A Profilometer was used to measure the Ra. Data were statistically analyzed with ANOVA and Tukey’s test (p<0.05). For CT, time (p=0.001) and material (p=0.001) showed statistical difference and interaction between both variables (p=0.001). The RLc, D and P presented higher CT than others. For BAT the P and D showed highest CFU/ml (p=0.008). The S and P showed higher values than AC and RLc in FS (p=0.001). For the EM S>D>P>AC>RLc (p=0.001). The D showed higher roughness than others groups. In conclusion the RLc showed lower biologic effect and the P presented better mechanical properties.

Keywords

Biofilm; cytotoxicity; mechanical properties; dental material

43

Evaluation of different filler contents in an experimental vinyl polysiloxane impression materials Meincke DK1, Ogliari AO1, Ogliari FA2.

1 Department of Restorative Dentistry, School of Dentistry, Federal University of Pelotas, RS

2 School of Materials Engineering, Federal University of Pelotas, Pelotas, RS

Abstract

The aim of this study was to evaluate the incorporation of different fillers in an experimental addition silicone (EAS). For this, an EAS regular base was formulated and on it was incorporated differents fillers concentrations, 20% e 40%, being those: calcined alumina (CA), cristobalite (CR), purest aluminum hydroxide (PAH), aluminum hydroxide (AH), halloysite (HL), aerosil (AE), calcined alumina (CA), fiberglass (FV), quartz (QT), diatomaceous earth (TD) and polymeric resin (PR). It was realized tensile test (RT), detail reproduction (RD), Shore A hardness (DS), elastic recovery (ER) were performed according to ISO 4823-2000 and scanning electron microscopy (SEM). The data were quantitatively analyzed by two-way ANOVA (p <0.05) and qualitatively. For RT was observed to perform better HAP40% (67.14 ± 7.4)% and AE40 (62.18 ± 9.0), while groups FV20% (4.94 ± 1.5)% QT20 (5.98 ± 0.7)% HA20 (4.30 ± 0.4)% HA40 (6.97 ± 0.9)% RP20 (3.15 ± 0.4)% and RP40 (3, 48 ± 0.3) had the worst performers. The SAE with addition of PAH40% and AE40% obtained the highest value averaging (68.7) and (67.3) of DS, respectively. The elastic recovery of materials generally were similar. The SEM images showed different morphologies of the particles. The addition of 40% of particles improves the properties of the material, except for the ability to copy.

Keywords

Dental Impression Materials, Microscopy.

.

44

Vertical misfit of implant frameworks produced by CAD/CAM system compared to two casted and welded systems Fontoura DC*1, Barros VM2, Vaz RR3, Magalhães CS4, Moreira AN5

Affiliation 1- FONTOURA, DC. Masters student in Dentistry, Specialization in Clinical Dentistry. College of Dentistry, Federal University of Minas

Gerais. Belo Horizonte, Brazil

2- BARROS, VM. PhD student in Dentistry, Specialization in Clinical Dentistry. College of Dentistry, Federal University of Minas Gerais. Belo Horizonte, Brazil

3- VAZ, RR. Assistant Professor. Department of Restorative Dentistry. Federal University of Minas Gerais. Belo Horizonte. Brazil

4- MAGALHÃES, CS. Associate Professor. Department of Restorative Dentistry. Federal University of Minas Gerais. Belo Horizonte.

Brazil

5- MOREIRA, AN. Associate Professor. Department of Restorative Dentistry. Federal University of Minas Gerais. Belo Horizonte. Brazil

Abstract

Passive adaptation of implant-supported prosthesis is a mechanical parameter that can favorably affect its longevity. This study compared the misfit of a framework produced by CAD/CAM system with two casted and welded systems. Four mini conical abutments analogs were installed in a master aluminum model. Three infrastructures were made over the analogs: the first was produced by CAD/CAM system, the second was casted in Cobalt-Chromium (Co-Cr) with mini conical abutment coping; and the third was casted in Cobalt-Chromium (Co-Cr) using Co-Cr cylinders of mini conical abutment. The vertical misfit among the framework and the analogs was measured using an optical microscope at 40X magnification (Mitutoyo TM 500). Both casted frameworks were assessed before and after laser welding. The mean misfit of each framework was calculated using six repeated measurements from each analog (45, 43, 33 and 35). The framework produced by CAD/CAM system presented the smallest vertical misfit (9.6 ±DPμm). The framework casted with mini conical abutment coping presented the highest mean misfit (108.6 ±DPμm). The framework casted with Co-Cr cylinders of mini conical abutment presented an intermediate mean misfit (29.2±DP μm). After welding, the mean misfit values were respectively 39.4 ±DP and 32.9±DP μm. The welding markedly decreased the vertical misfit of framework casted with mini conical abutment but this effect was not observed on the framework casted with Co-Cr cylinders.

Keywords

Dental Prosthesis Implant-Supported, Welding, Dental Prosthesis Design

Funding

Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

45

Posterior restorations choice: results from a Brazilian’ dentist survey Conceição DA*1, Nascimento GG2, Côrrea MB2, Demarco FF2,3.

1School of Dentistry, Federal University of Pelotas, RS 2 Post-graduate Program in Dentistry, School of Dentistry, Federal University of Pelotas, RS 3 Post-graduate Program in Epidemiology, School of Medicine, Federal University of Pelotas, RS

Abstract

The main purpose of this study was to assess general dental practitioners’ (GDP) restorative options for posterior restorations. Also, to test whether the amount of time of clinical practice or post-graduate training influenced these options. A cross-sectional study was performed using a closed questionnaire with general dental practitioners (n=276) in southern Brazil. Information regarding socio-demographic variables, level of specialization and time since graduation. First option regarding posterior restorations was collected. The type of composite used for posterior teeth was assessed, and also if the professionals used rubber dam to perform posterior composite restorations. The response rate was 68% (187). GDPs selected mostly composite resin as first choice for posterior restorations (72.2%). In relation to the type of composite used, most of the GDPs (74.5%) used microhybrid composite and 42.6% used rubber dam for posterior composite restoration application. Dentists with more time in clinical practice used less composite (p=0.014). Specialists used more frequently rubber dam to restore posterior teeth than did non-specialists (p=0.006). Composites were the first choice for posterior restoration among surveyed dentists. Microhybrid was the preferred type of composite and the use of rubber dam for composite resin placement in posterior teeth is not frequent. Amount of time in clinical practice, the working place and the level of specialization affected the dentists’ choices.

Keywords

Dental Restorations, Permanent; Composite Resins; Dentists

46

Calculation of the change in color of composite resin (in vitro) by two methods

Consolmagno EC*1, Marques MS1, Soares AF1, Bueno TL1, Bombonatti JFS1, Mondelli RFL1.

Insert affiliation here 1Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo,

Bauru/SP, Brazil.

Abstract

The beauty standard pursued currently has led many people to the dental office looking for esthetic and restorative treatment. The composite resin (CR) is one of the most popular restorative materials due to excellent aesthetic properties, mechanical strength, moderate cost compared to ceramics, as well as their ability to bond to enamel and dentin (through adhesive system). However, with the course of time, CR suffer color change, one of the main causes for its replacement and consequently lower longevity. For measuring the CR color, spectrophotometer is used and the color change and/or stability, called delta E (ΔE) can be calculated by the CIELab system or obtained directly from the equipment. Thus, this in vitro study work aimed to assess whether there are differences between the two methods of obtaining ΔE. Twenty specimens of the CR Z350 were made the dimensions 6 mm in diameter and 2 mm in height, light cured for 11 seconds (DB 685, Dabi Atlante, 1100mW/cm²), total energy density 12J, divided into 2 groups: A. Immersed in deionized water (control) and B. Immersed in grape juice for 2 hours. All specimens were analyzed before and immediately after polymerization after 7 and 14 days. For statistical analysis was employed paired t-test with 5% significance level. The results showed statistically significant difference between the two methods of obtaining ΔE in group B in all periods; in the group A, only after 7 and 14 days. It is concluded that the value of ΔE varies according to the method of production.

Keywords

Coloring agents, Esthetics dental, Dental restoration permanent

Funding

Research Initiation Scholarship Santander.

47

Evaluation of the effect of mechanical cycling in the mechanical properties of nanoparticulate resins

Souza EC*, Wingert A, Rigo A, Mota EG, Nogarett LM.

Inserir aqui filiação 1Departamento de Materiais Dentários, Faculdade de Odontologia, Pontifícia Universidade Católica do Rio Grande do Sul.

Abstract

This study aims to evaluate the mechanical behavior of four composite nanoparticulated resins concerning

diametral tensile strength and knoop microhardness after application of simulated mastication mechanical

load. Twenty samples of each material were fabricated. Ten samples were subjected to mechanical stress and

compared with the other ten samples for microhardness and diametral tensile strength. Data were submitted to

ANOVA and Tukey (a = 0:05). Statistically significant differences between groups were observed in

the microhardness (p <0.05) test. The results of the diametral tensile strength test showed statistically significant

differences between groups, however, the results did not show statistically significant

differences when comparing groups of the same material.

Keywords

Dental materials; composite resins; tensile strength.

48 Ability to remove the whitening pigments in the composites Eveline Claudia Martini Assessing the capacity of 35% hydrogen peroxide (Whiteness HP Blue Calcium, FGM) - HP, in removing pigments coffee, wine and Coca-Cola® in composite resin restorations. Using a metal matrix it was made 20 body-of-evidence (CPs) composite resin Opallis, FGM, color A1, 1 cm in diameter and 1 cm thick incrementally, each cured for 40 to 600 mW / cm2 with spectrophotometer VITA Easyshade Compact ®. After storage in distilled water (24h/37 º C), the CPs were stored in their drinks and distilled water (control) for 72 h at 37 ° C in an oven with daily exchanges of drinks. The HP 35% was applied for 40 min in three sessions with an interval of 7 days. The color was measured before and after immersion in the dye after bleaching and weekly for 21 days using the same spectrophotometer. Data were evaluated by ANOVA two factors and post-Tukey test (α = 0.05). It was found that showed color change (ΔE - mean/standard deviation) coffee (15.7 ± 2.0) and wine (15.2 ± 4.6) when compared to Coca Cola (4.8 ± 1.9). HP removed the pigmentation of CP's returning the original coloring, except for pigmented by coffee (12.9 ± 1.5). Coffee showed significant difference when compared to control (1.6 ± 0.6), unlike red wine (3.3 ± 0.6) and Coca-Cola ® (2.1 ± 0.9). It was concluded that all the dyes solutions pigmented resin composite. However, HP has succeeded in promoting an improvement in pigmentation of the samples, except for the stained coffee that did not return to the original color. In addition, HP did not clear the composite, since no sample had regression of initial color used

49

Evaluation of ceramic reinforcement from adhesive cementation with different types of resin cements through the weibull analysis Soares EF*1, Colmanetti JC1, Guarda GB1, Spazzin AO1, Costa AB1, Correr AB1, Moraes RR2, Consani RLX1, Sinhoreti MAC1, Correr-Sobrinho L1.

Insert affiliation here 1School of Dentistry, State University of Campinas, SP, 2School of Dentistry, Federal University of Parana, RS.

Abstract

The aim of this study was to evaluate the reinforcement of feldspathic ceramic from resin cements Variolink Venner (VV), Variolink II - base paste (VB), Variolink II - dual (VD), Z350 Flow (ZF) and Tetric N-Flow (TF) tested on their flexural strength (Rf), elastic modulus (E) and Weibull analysis. The Rf and E of the cements were evaluated throw bending test of three points. Disks of ceramic (12mm diameter x 0.8mm thick) went throw etching procedure with 10% hydrofluoric acid, silane was carefully spread and the cement was applied until it reached a thickness of 120 ± 20μm. Mechanical strength of the samples was determined using biaxial bending test (n = 30). The data of biaxial flexural strength were subjected to ANOVA, Weibull analysis and Tukey’s test (5%). The Mean ± SD of Rf (MPa) and E (GPa) were, respectively: ZF = 95 ± 4.3 ± 0.4 9a and b; TF = 85 ± 0.6 3.1 ± 16a and c; VV 11b 64 ± 2 and ± 0.4 d; VB = 83 ± 11a and 3.1 ± 0.5 c; and VD = 100 ± 0.7 6.1 ± 14a and a. The biaxial strength (MPa) - the position z = 0 ( the ceramic surface at the interface with the cement ) was: C = 71 ± 12b ; ZF = 138 ± 20a; TF = 134 ± 26a ; VV = 141 ± 33a ; VB = 165 ± 38a; and VD = 160 ± 50a . At position z = - t2 (resin cement surface facing the ring) was: ZF = 11 ± 4ab; TF = 9 ± 2bc; VV = 5 ± 1c; VB = 13 ± 2ab; and VD = 21 ± 7a. It was concluded that the mechanical properties of these resin cements did not influence the strength of the ceramic itself, but it does influence final mechanical strength of ceramic/cement set.

Keywords

Ceramics, cementation, physical properties

Funding

PIBIC / CNPq

50

Reliability of zirconia-veneer crowns under sliding fatigue: effect of type of internal treatment for cementation Monteiro EBC *1, Ramos GF1, Marinho RMM1

1School of Dentistry, Science and Technology Institute, State University of São Paulo, SJC

Abstract

The aim of the present study was to evaluate the fatigue life of zirconia crowns veneered with feldspathic porcelain. Sixty first molars were

selected, prepared for full crown and divided into 3 groups: primer (MDP) ; tribochemical silica coating (Rocatec Soft + silane) ; glaze ( Vita

Akzent + Hydrofluoric acid 10 % + silane) . The veneering porcelain was applied respecting the the anatomy of upper first molar. The zirconia

inner surface was treated according to the group, cemented using resin cement. The sliding fatigue test was performed by sliding the piston

(3.18 mm in diameter) from inner side of the mesial buccal cusp up to the central fossa, cyclic loaded 2x106 times or until specimens fail,

with a weight of 200 N at 3 Hz with a fatigue chewing simulator. Every 500,000 cycles, the specimens were evaluated for the presence of

flaws in stereomicroscope (10 ×). To determine the probability of survival (reliability), Weibull analysis was performed, considering a two-

sided confidence interval of 95 %. The predominant type of failure was cracking and chipping of the feldsphatic porcelain followed by

delamination. Weibull parameters (beta and eta) for primer, tribochemical silica coating and glaze groups were respectively 2,226344 e

1,762026E+06 cycles; 2,197559 e 1,050772E +06 cycles; 2,178343 e 1,192208E +06 cycles.The reliability features with a confidence interval

of 90 % were significantly different between tribochemical silica coating and primer groups, indicated by the non-overlaping contour plots .

Keywords

Fatigue, Ceramics, Air abrasion

Funding

FAPESP- Fundação de Amparo à Pesquisa do Estado de São Paulo

Process Number: 2013/03215-8

51

Influence of the adhesive system in the sealing ability of photopolimerizable temporary materials Kreps EL*1, Reiznautt CM.¹, Peralta SL2, Piva E3, Lund RG3,

1 Academic School of Dentistry, Federal University of Pelotas, RS 2 Post graduate School of Dentistry, Federal University of Pelotas, RS 3 Professor Dr. School of Dentistry, Federal University of Pelotas, RS

Abstract

The aim of this study was to evaluate the effect of application of Single bond (SB) and Clearfil SE Bond (CS) in the microleakage of two temporary restorative materials. Seven groups were tested (n=10); Bioplic (B); Fermit N (F), B + SB (BSB); F+ SB (FSB); B+CS (BCS); F+CS (FCS); and a Glass ionomer cement (GIC) as control. Seventy bovine incisors were used. Cavities with dimensions of 4mm of diameter and 2.5mm of depth were prepared in the buccal surface. Teeth were stored in distilled water until the assay. Subsequently, they were filled with or without application of the adhesive, covered with a polyester strip and cured for 20 s. Immediately, they were stored for 24h at 23°C in 1% methylene blue solution and thermocycled for 500 cycles. Two coats of nail varnish were applied to the entire surface of the teeth, except for their filling areas and 2mm of their margins. The specimens were again immersed in methylene blue solution, for 10min at 23°C, and, after that, they were washed in tap water. The specimens were serially sectioned longitudinally in a buccal-lingual plane in order to obtain two slices. Following sectioning, dye infiltration into each slice was viewed under 5x magnification. Every slice was photographed, digitalized and evaluated in image tool software. Data were subjected to ANOVA on ranks followed by SNK test (p <0.001). The results are presented in % (Mean±Sd) were: B (55.9±23)b; F (88±20)a; BSB (51.8±4)b; FSB (40.3±17)c; BCS (25.6±24)d; FCS (29.7±23)d and GIC (20.4±12)d. It was concluded that the use of adhesive decreased the microleakage and the use of Clearfil SE Bond increased the sealing.

Keywords

Microleakage, adhesive system, dental materials.

52

Evaluation the bond strength and nanoleakage in eroded dentin subjected a treatment deproteinization. Siqueira FSF*1, Cardenas AFM1, Gomes GM1, Chibinski ACR1, Gomes OMM1, Gomes JC1.

1School of dentistry, Department of restorative dentistry, State University of Ponta Grossa, Ponta Grossa, Paraná, Brazil.

Abstract

This “in vitro” study evaluated the effect of the deproteinization of the eroded dentin in bond strength (TBS) and nanoleakage (NI) using three different adhesive systems. Forty-five molars were cut at medial dentin. After standardization of smear layer, teeth was randomly divided into 3 groups (n=15), according to the adhesive system used: GS1 - Adper Single Bond™ 2 (3M-ESPE™); GS2- AdheSE® (Ivoclar/Vivadent); GS3- Single Bond Universal™ (3M-ESPE). Previously to the application of the adhesive system, each group was divided into 3 subgroups (n=5), according to the treatment of the dentin: A1– Sound Dentin (control), A2- eroded dentine and A3- eroded dentine + deproteinized with NaOCl ( 5.2% ) for 40 sec. After the application of the adhesive systems according to the manufacturer's instructions, the teeth were restored and sectioned to obtain “sticks-like” (0.8 mm2) and submitted to TBS test. Two “sticks” of each experimental condition were randomly assigned for NI analysis by SEM. The TBS and NI data were analyzed by 2 way ANOVA complemented by Tukey's test (α=0.05). The TBS means for GS3A3 (41.86 ± 5.80 MPa) was statistically higher to GS1A3 (33.42 ± 4.37 MPa) and GS2A3 (21.22 ± 1.79 MPa). The GS3A3 groups had the lowest NI mean % (14.48 ± 5.47). The dentin deproteinization resulted in increased TBS in the eroded substrate for the groups in which self-etch adhesive systems were applied. For the NI, the best conditions were obtained for the Single Bond Universal adhesive system.

Keywords

Tooth Erosion, Sodium Hypochlorite, Tensile Strength

Funding

CAPES

53

Effect of air-polishing procedure with glycine and bicarbonate powders on glass ceramic and composite resin surfaces.

Murillo-Gómez F*1, 2, Sartori CG1, Soares AB3, Goes MF1

1Restorative Dentistry Department, Dental Materials Division, Piracicaba Dental School, Campinas State University, SP, Brazil. 2Restorative Dentistry Department, School of Dentistry, University of Costa Rica, San José, Costa Rica. 33M ESPE R&D Laboratory, Sumaré, SP, Brazil.

Abstract

The aim of this study was to evaluate the effect produced by air-polishing procedure using glycine-based powder and sodium bicarbonate-based powder on different restorative materials’ surfaces. There were used the nano-filled composite resin Z350 XT (3M ESPE), the nano-hybrid composite resin IPS Empress direct (Ivoclar Vivadent) and the glass-ceramic Vitablock Mark II (Vita). Disk specimens (n=10) were made (6.05 mm X 0.5 mm). They were divided in 2 groups of 5 specimens each to be air-polished with sodium bicarbonate (BS) (Polidental) and glycine (GCP) (Clinpro Prophy Powder, 3M ESPE). The Profi Neo polishing device was used at a 5 mm working distance, for 5s and 2 bar pressure. A profilometer (Surcoder SE 1700) working at 0.5 mm/s was employed to evaluate roughness and an scanning electron microscope (SEM) (JEOL-LV 5600) was used to evaluate surface morphology. Roughness was measured in all specimens before being polished to serve as control. Post-polishing roughness values were analyzed using variance analysis and Tukey’s test (p<0.05). Group IPS-BS (0.62±0.20 µm) showed significantly higher values than groups Z350 XT-BS (0.16±0.02 µm) and VITA-BS (0.20±0.12 µm). Group IPS-GCP (0.29±0.13 µm) was significantly lower than IPS-BS but not different from Z350 XT-GCP (0.21±0.09 µm) e VITA-GCP (0.17±0.05 µm). BS produced more surface alterations on IPS and Z350 XT and higher roughness values on IPS than GCP. For VITA, the alterations produced by BS and GCP weren’t different between them.

Keywords

Dental Materials, Dental Prophylaxis, Glycine.

54

Pre-heating mitigates composite degradation

Silva, JC1, Reges RV2, Rege ICC3, Castro FLA*4.

1Private Clinician, Goiânia, GO. 2Graduate Program in Dentistry - Dental Materials, School of Dentistry, Paulista University- UNIP, Goiânia, GO.3 Graduate Program in Dentistry - Oral Radiology, School of Dentistry, Paulista University – UNIP, Goiânia, GO.4 Graduate Program in Dentistry - Restorative Dentistry, University Center of Anápolis – UniEVANGÉLICA, Anápolis, GO.

Abstract

This study evaluated the degradation of three composites via analysis of both radiopacity (R) and silver penetration by

scanning electronic microscopy / dispersive X-ray spectroscopy (SEM / EDS). Composite brand and temperature were the

variables evaluated. Thirty specimens were built up using a metallic matrix ( 2x8mm ) and the composites Durafill VS ( Heraeus

/ Kulzer ) , Z - 250 ( 3M/ESPE ) and Z - 350 ( 3M/ESPE ) . The resins were cured at 25°C or 60°C. The specimens were stored

sequentially: 1 - distilled water 37°C-7 days + 0.1 N sodium hydroxide-14 days, 60°C; 2 - silver nitrate at 50 %- 10 days, 60 ° C.

Before and after each storage, specimens were radiographed using an x-ray unit and digital radiographs were evaluated to

verify the grayscale obtained. After storage in silver nitrate solution, samples were examined using SEM/EDS tool for checking

the depth of silver penetration. The data of R and SEM/EDS were analysed using ANOVA and Tukey tests (α = 5 %). As a result,

it was observed that the resins had the same R behaviour within the storage conditions studied: Durafill < Z-350 < Z -250 (p <

0.05). The depth of silver penetration in the composites was Durafill >Z-350 > Z -250 (p < 0.05). The materials presented R

values at 25°C lower than at 60°C after storage in water / sodium hydroxide (p < 0.05). There was a lower penetration of silver

in the preheated resin (p < 0.05). It was concluded that heating the resin at 60 ° C mitigated the degradation of materials

under both R and SEM / EDS analysis.

Keywords

Composite Resins; Hot Temperature, Polymerization

Funding

This research was partially supported by Fundação de Amparo à Pesquisa do Estado de Goiás – FAPEG, Edital Nº02/14-

55

Do metal post-retained restorations result in more root fractures than fiber post-retained ones? A systematic review and meta-analysis.

Figueiredo FED*¹Silva ALF*2, Souza CD2, Filho PRM³.

Insert affiliation here 1Dentistry Post-Graduate Program, Federal University of Sergipe, SE

Abstract

This systematic review aimed to determine the incidence rate of root fractures observed for restorations retained with metal- and fiber-posts. A MEDLINE search for clinical studies using fiber- and/or metal-post retained restorations with more than 5-year of follow-up was performed at January 2014. Seven randomized clinical trials and 7 cohort studies were included at inclusion criteria. Data of root fractures incidence and survival rates were extracted of studies and a meta-analysis was performed. Despite the high heterogeneity between studies, we observed a survival rate of 90.0% (95% CI, 85.5-93.3) for metal-based posts and 83.9% (95%, CI 67.6-92.8) for fiber-reinforced posts, but without significant difference (1.07; 95% CI, 0.8-1.4). When we analyzed the root fracture incidence per 1000 posts-year; no significant difference was found between metal- (5.13; 95% CI, 4.05-6.21) and fiber-post (4.78; 95% CI, 4.28-5.27) retained restorations. A 2-fold increase in the incidence rate of root fracture for prefabricated metal posts and carbon fiber posts compared to cast metal posts and glass fiber posts, respectively. Therefore, according to the selected studies, there is no significant difference between metal retained restorations and the ones retained with fiber posts.

Keywords

Endodontically treated teeth, dental dowel, Meta-analyses

56

Evaluation of the shear strength of orthodontic brackets bonded to indirect resin surface Degrazia FW*1, Dellazzana FZ2, Valandro LF2, Collares FM1.

Insert affiliation here 1LAMAD, School of Dentistry, Federal University of Rio Grande do Sul, RS 2School of Dentistry, Federal University of Santa Maria, RS

Abstract

The aim of this study was to evaluate the shear bond strength (SBS) of the interface between orthodontic brackets and indirect resin with different surface treatments. Forty disks of indirect resin SR Adoro (Ivoclar Vivadent, Brazil) were made. Half of the disks were air-abraded with Aluminum Oxide – 50 µm + silanization, and the other half were air-abraded with Silicon Oxide – 110 µm + silanization. Thus, metallic brackets Roth Max (Morelli Ltda., Brazil) were bonded to the conditioned surfaces with Transbond XT (3M/Unitek, USA) adhesive system. Half of the brackets surface was conditioned with Aluminum Oxide – 50 µm, resulting the following groups (n=10): G1 – air-abraded resin and bracket with Aluminum Oxide, G2 – air-abraded resin with Aluminum Oxide, G3 – air-abraded resin with Silicon Oxide and bracket with Aluminum Oxide, and G4 – air-abraded resin with Silicon Oxide. The shear bond strength results (in MPa±standard deviation) were as follows: G1 – 16.37±5.2; G2 – 18.57±6.56; G3 – 19.65±6.32; e G4 – 17.57±5.2. No significant differences were found in SBS among groups (p= 0.638). Statistically significant difference occurred in bond fracture pattern among the tested groups (p< 0.05). The different surface treatments did not change SBS among groups. However, the air-abraded bracket surface groups showed higher frequencies of cohesive fracture in the indirect resin surface.

Keywords

Resin Cements, Orthodontic Brackets, Dental Bonding

57

Bonding evaluation of experimental phosphate and sulphur-based primers on metal alloys Leal FB*1, Piva EV1, Azevedo EC1, Ogliari AO1, Pilownic KJ1, Pinto MB1, Camacho GB1, Petzhold CL2, Ogliari FA3.

1School of Dentistry, Federal University of Pelotas, RS 2Institute of Chemistry, Federal University of Rio Grande do Sul, RS 3Engeenering Materials School, Federal University of Pelotas, RS

Abstract

The aim of this study was to evaluate the effect of three experimental primers prepared with synthesized phosphorous and sulphur monomers (HEMA-P, ETMA and the mixed of HEMA-P/ETMA) on bonding of metal alloy nickel-chromium (NiCr), silver-palladium (AgPd) and silver-gold (AgAu). The metal alloys were treated with experimental primers: HEMA-P, ETMA, HEMA-P/ETMA and Alloy Primer (Kuraray Noritake Dental Inc., Okayama, Japan) was used as commercial reference. Cylinders of resin cement were built-up after application of tested primers on alloy surface. Samples were stored in distilled water at 37º C for 24 h before to be loaded in shear using a mechanical testing machine. Shear bond strength (SBS) was recorded in MPa. Failure modes were classified under magnification as adhesive and mixed failure. Data were submitted to a Two-way ANOVA and Student–Newman–Keuls’ test. The statistically highest Shear Bond Strength was observed with commercial primer in the AgPd alloy (32.6±4.6), while the lowest value was shown with commercially available primers (7.5±2.4) and experimental HEMA-P/ETMA (8.5±3.5) in the NiCr alloy (p<0.05). There was a predominance of adhesive failure, with the exception of commercially available primer where mixed failures were predominant. It can be concluded that formulations of metal primers containing primers HEMA-P or ETMA should be considered for use in adhesive protocol of NiCr alloys.

Keywords

Metals. Alloys. Dental materials.

58

DEVELOPMENT OF EXPERIMENTAL ROOT CANAL SEALERS WITH THE ADDITION OF α-TRICALCIUM PHOSPHATE, OCTACALCIUM PHOSPHATE AND HYDROXYAPATITE

Rostirolla FV*, Leitune VCB, Samuel SMW, Collares FM.

Insert affiliation here 1LAMAD, School of Dentistry, Federal University of Rio Grande do Sul, RS

Abstract

The aim of this study was to evaluate the influence of α-tricalcium phosphate, octacalcium phosphate and hydroxyapatite addition on the radiopacity, flow, film thickness and degree of conversion on experimental root canal sealers. The experimental root canal sealers were formulated by mixing 70 wt.% UDMA, 15 wt.% BISEMA and 15 wt.% GDMA. CQ, DHEPT and BP were added to produce a dual-cure root canal sealer. Three experimental groups (GHA, GOCP e GαTCP) were formulated by mixing 10wt% of the corresponding calcium phosphate, 40wt% ytterbium trifluorate to the monomer blend. A control group (G0) was formulated without the phosphates addition. Radiopacity was evaluated using a digital system and an aluminium step wedge (n=5). Flow (n=3) and film thickness (n=3) were conducted in accordance with ISO 6876 and the degree of conversion were evaluated immediately, 24 hours and 7 days after the sealers polimerization. The data were analyzed using one-way ANOVA, two-way repeated measures ANOVA and Tukey’s post hoc test (α=0.05). All groups had levels of radiopacity in accordance with ISO 6876. The flow ranged from 14.63 to 21.61mm and only the G0 have differed from the others (p<0.05). Film thickness was lower than 50 μm for all the groups (ISO 6876). All groups presented an increase in the degree of conversion over time, but only GHA showed statistical significant difference after 7 days (p<0.05). The addition of 10% of the calcium phosphates to root canal sealers did not alter the properties tested.

Keywords

Calcium phosphates; endodontics; canals sealer

Funding

59

Design effect on the fatigue life of crowns with zircônia intaglio Ramos GF*, Monteiro EBC, Bottino MA, Melo RM

School of Dentistry, State University of São Paulo, SP

Abstract

The study evaluated the fatigue life of completely or partially porcelain / glaze covered crowns, determining their reliability with Weibull analysis . Forty molars were selected and prepared for first molar full crown and divided into two groups (n = 20): Traditional -crowns with zirconia infrastructure coated with feldspathic porcelain; Modified - crown partially covered with veenering porcelain. All specimens were treated with glaze layer. Specimens were submitted to mechanical cycling (100N, 3Hz) using a piston (Ø=6 mm) until the specimens failure or up to 2x106 cycles. Every 500,000 cycles the specimens were inspected for the presence of flaws in stereomicroscope (10 ×). The predominant type of failure was cracking and chipping of the feldsphatic porcelain followed by delamination and debonding . Weibull parameters (beta and eta), with two-sided confidence interval of 95 % , were respectively: Traditional - 2.027215 and 1.198195 +06 cycles ; Modified - 1.274541 and 4.448019 +06 cycles . In the contour plot, it was possible to observe significant statistical difference between the two groups, with Modified performing better than the Traditional group. According to the results, it was concluded that the modified crowns presented higher long- term reliability compared to the traditional crowns.

Keywords

Design, Ceramics, Fatigue

Funding

Foundation for supporting research in the state of São Paulo- FAPESP

Process n°2013/05314-3

60

Remineralization of experimental dental bioactive desensitizers

Abuna G1*, Babbar A2, Bacelar R1, Feitosa VP3, Giannini M1, Sauro S4, Sinhoreti MAC1

Insert affiliation here 1 State University of Campinas, Piracicaba Dental School, São Paulo, Brazil 2 King’s College of London, London, UK 3 Federal University of Ceara, Fortaleza, Brazil 4 University Cardenal Herrera, Valencia, Spain

Abstract

The aim of this study was to evaluate the remineralization induced by experimental resin-based agents containing bioactive glass and calcium-phosphates. 35 Human dentin disks (+/-1mm thick) were treated (n=5) using the following agents: 1) Oxagel; 2) Resin [15% GDMA-P, 5%HEMA, 15% TEG-DMA, 15% UDMA 15% H2O, 25% ethanol, 3.5% polyacrilic acid, 3.5% sodium trimetaphosphate, 3%]; 3) Resin-Phosphates [Resin+20wt% di-calcium phosphate]; 4) Resin-BAG[Resin + 20wt% Bioglass 45S5) 5)Resin-ßPort [Resin+20 wt% ßTCP-modified Portland cement]; 6) Resin-BAGZn [Resin+20 wt% polycarboxylated zinc-modified BAG]. Dentin mineral variation was monitored using attenuated total reflection-Fourier transform infrared (ATR-FTIR). SEM ultra-morphology analysis was also performed to evaluate the mineral deposition in dentine. The outcomes of FTIR showed a decrease of minerals deposition after 10 months for all the groups. Group 6 showed a high initial presence of mineral compounds (1165 cm-1, 1080 cm-1), however the mineral presence after storage was the same as others. Group 5 was the only one that retains some of the initial apatite deposition (1040 cm-1). Group 2 showed an important degradation of Aromatic Bis-phenol compounds (1610 cm-1). SEM results showed the degradation and release of the superficial minerals, in all the groups, for the Group 1 after 10 months showed morphology equal to a normal dentine. The desensitizer doped with bioactive glasses in a resin adhesive blend are highly recommended, however not all the mineral deposition last after storage and just the resin adhesive could degraded a Bis-phenol aromatic compounds Keywords

Dentine desensitizing agents, Tooth Remineralization,

Funding

CAPES PROEX.

61

Longevity of restorative materials used in posterior primary teeth of children attending to dentistry school of pelotas.

Pinto GS*1, Oliveira LJC1, Mattia ALG2, Fortes EK2, Cumerlato C2, Romano AR1, Bonow MLM1, Corrêa MB1, Torriani DD1, Demarco FF1 .

1Graduate Program in Dentistry, Federal University of Pelotas, RS 2School of Dentistry, Federal University of Pelotas, RS

ABSTRACT

The aim of this retrospective study was to evaluate the longevity of restorative materials used in restorations in posterior primary teeth of children attending to a Pediatric Clinic of the Dentistry School of Pelotas. Patients records of 329 children were used for collecting and analyze data. A total of 565 restorations in primary teeth were included in the study. The longevity of restorative materials from their placement until failure (up to 4 years of follow-up) was assessed using Kaplan- Meier survival curves with log-rank test. Multivariate Cox regression analysis with shared frailty was used to assess factors associated with failure. Up to 4 years of follow-up , annual failure rates were 9.5 % for composite restorations, 12.2% for light-cure glass ionomer and 12.9 % for conventional glass ionomer with statistical difference between the materials (p = 0.014). Glass ionomer restorations had a higher risk of failure over time compared to composites (HR 1.86 95% CI 1.17 to 2.97). Class II restorations showed lower survival rate of Class I restorations (p = 0.031) in crude analysis, but lost significance after adjustments. Our results suggest that, in this sample, the material influenced the survival rate of posterior restorations of primary teeth, and the composite restorations showed the best performance.

Keywords

Composite Resine. Glass Ionomer Cements. Deciduous.

62

Effect of delayed placement of composite resin after bleaching on enamel bond strength

Sehnem GD*1, Pimentel AH1, Isolan CP1, Munchow EA1, Valente LL1, Moraes RR1.

1School of Dentistry, Federal University of Pelotas, RS.

Abstract

This study investigated the influence of time delay between dental bleaching and placing a composite resin (CR) restoration on the enamel shear bond strength (SBS, MPa). Seventy bovine incisors were stained in coffee solution; sixty were bleached with hydrogen peroxide-based agent (Whiteness HP 35%, FGM) and ten were not bleached (control). The teeth were assigned into seven groups according to the time delay for placing the CR: C– control; I– immediately (no time delay); 24h– 24h delay; 3d– 3 days; 7d– 7 days; 14d– 14 days; and 28d– 28 days delay. The vestibular surfaces were wet-flattened with 600-grit abrasive papers. Surfaces were etched with 37% phosphoric acid for 30s and adhesive was applied (Single Bond 2, 3M ESPE). A silicon mold with two cylindrical orifices (1.5mm diameter) was placed over the samples and the adhesive was photoactivated for 20s. The orifices filled with CR (Filtek Z350 XT, 3M ESPE), which was photoactivated for 20s. After 24h, the SBS test was conducted in a mechanical testing machine and failure modes were classified. For each group, 20 resin cylinders were tested. Data were analyzed by one-way ANOVA (α=0.05). SBS means (standard deviations) were: C= 12.7 (4.8); I= 14.8 (2.9); 24h= 20.7 (6.7); 3d= 15.7 (2.9); 7d= 15.5 (5.0); 14d= 14.7 (7.1); and C= 17.1 (7.0). No significant differences were detected (p=0.104). Adhesive failures were predominant (67%), followed by mixed failures (29.5%). Dental bleaching did not affect the resin-enamel bond strength irrespective of the time delay before placing the restoration.

Keywords

Tooth Bleaching. Shear Strength. Composite resins.

63

Effect of desensitizing agents on shear bond strength of a two-step conventional adhesive system Rauber GB*1, Dall Magro E2

1 Graduated in Dentistry, School of Dentistry UPF, University of Passo Fundo, RS. Masters Student in Restorative Dentistry,

Federal University of Santa Catarina, SC.

2 Department of Restorative Dentistry, School of Dentistry, University of Passo Fundo, RS.

Abstract

The aim of this in vitro study was to evaluate the shear bond strength of an adhesive system after the application of

different products for dentin hypersensitivity. Forty crowns of extracted human premolars were selected and embedded in

acrylic resin. The crowns was worn with a diamond bur to expose the dentin surface and polished in a polishing machine

with a 600grit SiC-abrasive paper for standardization of sample. The samples were randomly divided into four groups (n =

10) according to desensitizing agent: CONTROL: untreated dentin + acid + adhesive + resin; GLUMA: acid + Gluma Comfort

Bond (Heraeus, Germany) + resin; DESENSIBILIZE: Desensibilize KF2 % (FGM, Brazil) + acid + adhesive + resin; NANOP: NANO

P (FGM, Brazil) + acid + adhesive + resin. For the curing of Ambar adhesive system (FGM, Brazil) and Opalis composite resin

(FGM, Brazil) a light curing Radiii (SDI) with light intensity of 1.200 mW/cm2 was used. The shear test was conducted using a

universal testing machine (EMIC DL 2000, Brazil) at a speed of 0.5 mm/min until fracture. The results obtained were for the

CONTROL 14.66 MPa (±6.13); GLUMA 21.71 MPa (±12.9); DESENSIBILIZE 15.32 MPa (±8.24); NANOP 12.60 MPa (±5.81). The

statistical analysis using ANOVA was realized and no were found significant difference between groups at a significance

level of 5 % (p = 0.128).

Keywords

Shear Strength, Dentin Desensitizing Agents, Dentin Bonding Agents

64

Bond Strength of Glass fiber posts fixed with different adhesives systems

Nima G*1, Abuna G1, Sinhoreti MAC1,de Paula AB1.

1 Piracicaba Dental School, State University of Campinas-UNICAMP, Piracicaba, SP, Brazil

Abstract

The aim of this study was to assess the bond strength (BS) of glass fiber posts fixed with different adhesives systems, under the following statements; different dentinal regions (cervical, middle) and adhesive layer. For this purpose, 40 bovine roots were prepared: crowns were removed, and standardized to 17mm of root’s size. The radicular canals were prepared to been restored with glass fiber posts (exacto 2; Angelus), they were cemented by the following groups: G1 RelyX ARC (ARC)/Scotchbond multipurpose (SBM), G2 ARC/Single Bond Universal (SBU), G3 Rely U200/SBU and G4 RU2. After 24 hrs the latters were sectioned and identified by regions (cervical and middle), getting 4 slabs (+/- 1mm) for region, and subjected to push-out bond strength test, at 1 mm/min speed. The failure pattern and adhesive layer were analyzed with Scanning Electronic Microscopy SEM. Data were analyzed with two way ANOVA and Tukey (p<0.05). the outcomes showed RU got the highest results G3 (14,5 +/- 3.7 MPa) paired to G2(10,28 + 2,32) and G4(10,11 + 2,24), G1(12,24+3,17) in the other hand did not present the same difference. Radicular regions did not affect the BS, the most frequent failure pattern was adhesive between dentin and resin cement. Summarizing we can say that the association of a self etch resin-based cement with a multimode adhesive could improve the BS, without the interference of radicular region.

Keywords

Dental cements, Dental adhesives, Microscopy Electon Scanning

Funding

CAPES

65

The effect of resin cement systems and the access levels to root canal on the shear bond strength of fiber glass posts Miranda GLP*1, Daleprane B1, Pereira CNB1, Bueno AC1, Moreira AN1, Magalhães CS1

Insert affiliation here 1School of Dentistry, Federal University of Minas Gerais, MG

Abstract

This in vitro study evaluated the effect of resin cement systems and the levels of access to root canal on the shear bond strength of fiber glass posts. The roots of 135 bovine teeth were endodontically treated and divided according to the level of access to the root canal, as following: coronal, with 15mm-post space; medium, with 10mm-post space; and apical, with 5mm-post space. The fiber glass posts (Reforpost #3, Angelus) were cemented using RelyX ARC / Adper Scotchbond Multipurpose Plus (3M ESPE, C&B / All- Bond 2 (Bisco) or RelyX U200 (3M ESPE), totaling 9 groups (n = 15). After 7 days, the roots were cut in the coronal, medium and apical thirds, obtaining two specimens (thickness=1mm) on each third. The specimens were then subjected to the push-out test (0.5 mm / min, 200N) and the maximum force to extrude the post was recorded. The effect of the factors was verified by ANOVA and Tukey test (p <0.05). There was no significant effect of resin cement systems on the bond strength (p >0.05). The levels of access to root canal had a significant effect (p = 0.029) on the bond strength in the apical third of the root. When the bond strength was measured in the same level of access to root canal, it was higher in the apical than in the coronal third (p = 0.001). It was concluded that under the conditions studied, the resin cement systems showed similar shear bond strength. Regardless of the level of access to the root canal, the bond strength was higher in the apical than in the coronal third.

Keywords

Resin cements, Root canal posts, Dental adhesives

Funding

FAPEMIG (CDS-APQ 01545-13)

66

Influence of waiting time of dual-curing resin cements in GC and bond strength.

Guarda GB*, Nizo PT, Souza-Junior E, Vitti RP, Sinhoreti MAC, Correr-Sobrinho L

Department of Restorative Dentistry, Dental Materials Area, Faculty of Dentistry of Piracicaba, State University of Campinas, SP.

Abstract

The effect of time of chemical cured were evaluated in dual-curing resin cements 1 and 5 minutes, the degree of conversion and durability of the bonded in dentin. Was used for bonding with dentin 45 human molars and 3 cementation systems (Single Bond 2/RelyX ARC - 3M ESPE, Excite / Variolink II - Ivoclar Vivadent, Optbond Solo Plus / Nexus 3 - Kerr), which cemented resin blocks. We used three procedures: a – light curing immediately after cements mixture; b - after 1 minute of chemical cured; c - after 5 minutes of chemical cured. Samples were photoactivated with LED Bluephase G2, with irradiance of 1,200 mW/cm2 for 40 seconds. After 24 hours, the teeth were sectioned and tested for microtensile on universal testing machine (0.5 mm / min) Instron. Half of the sticks were tested, and the other stored in water. For the degree of conversion cement samples were prepared and evaluated by FTIR. Samples were light cured under the same conditions mentioned. Data for microtensile bond strength and degree of conversion were evaluated by ANOVA and means compared by Tukey test. Results showed no differences in the values of resistance to bonded, being higher and stable at 6 months in group "c". No differences were found in the degree of conversion, but Nexus 3 showed a lower degree of conversion. The 5 minute wait in the polymerization increases the bond strength to dentin.

Keywords

Resin Cements; Tensile Strength

Funding

CNPq.

67

Influence of inorganic filler particles on optical proprieties and surface roughness of resin composites Rego GF*, Ferraz LG, Silva EM, Schneider LFJ, Cavalcante LMA

Insert affiliation here

Analitic Laboratory of Restorative Biomaterials (LaBiom-R), School of Dentistry, Federal Fluminense University

Abstract

Color stability and gloss retention are vital features on composite restorations. However, some factors related to the composite and to the patient may compromise the aesthetic success, such as the size of the filler particles used in the composite or the brushing and chewing done by the patient. Organic and inorganic parts of the composite are being improved in order to overcome these challenges, but there are not enough data in the literature comprising the color stability and gloss retention of resin composites with filler nanoparticles after exposure to the adversities of the oral environment.

In this study, there were studied the roughness, color stability and gloss retention of microhybrid and nanocomposite resins, before and after being exposed to cycles of immersion in staining solutions (coffee, distilled water and Coke®). The cycles consisted of immersion in these staining solutions for 4 hours. Before and after the cycles, the samples manually brushed. All the analysis was made before and after 15 days of cycles.

For the results of roughness, there was no difference among the groups. However, for color stability all the groups showed statistic difference, despite the filler size of the composite and the staining solution, and the most outstanding difference was of the Filtek Z350 composite. As for gloss retention, there was a tendency for lower values compared to the initial ones. Thus, we concluded that there are no significant differences while using these materials, even when they have different sizes of filler particles.

Keywords

Resin Composites, Nanotechnology, Aesthetics

Funding

Programa Institucional de Bolsas de Iniciação em Desenvolvimento Tecnológico e Inovação – PIBITI 2010/2011 da Agência de Inovação da Pró-Reitoria de Pesquisa, Pós-Graduação e Inovação da Universidade Federal Fluminense.

68

Color stability of a composite resin after the application of a surface sealant. Ruschel VC1, Chraim GG*1, Maia HP1

1Dentistry Department, Federal University of Santa Catarina, SC

Abstract

The objective of the present study was to evaluate the effect of a surface sealant on the color stability of a nano hybrid composite resin. Forty composite resin discs (ø 12 mm x 2.5 mm) were fabricated (A2, Esthet-X HD, Denstply) and divided into 4 groups. In two groups the Immediate Polishing (I) was performed: G1I - Polishing silicon rubber tips (Jiffy Polishers, Ultradent); G2I - Polishing + Permaseal (Ultradent). In the other two groups the Late Polishing (L) was performed 48 h after specimens preparation: G1L - Polishing; G2L - Polishing + Permaseal. The specimens were stored in distilled water at 37 ºC for one year. The color difference (ΔE) for each specimen was obtained from the values of L* a* b* measured before and after one year of storage, using a reflection spectrophotometer (Vita Easyshade). Data were submitted to ANOVA one-way and Tukey (α=5%). There was no significant difference in the immediate polishing between G1I (ΔE = 2.04 ) and G2I (ΔE = 2.41) (p > 0.05). In the delayed polishing the G1L (ΔE = 3.59) was statistically higher than G2L (ΔE = 2.90) (p < 0.05). The application of sealant showed no significant difference regarding to immediate and delayed polishing. The lower values of ΔE were obtained with group G1I and the higher values with G1L. Therefore, the application of the sealant surface did not influence the color change of a composite resin in the immediate polishing, but was significantly lower in the delayed polishing.

Keywords

Composite Resins, Dental Materials, Color

69

Modification of enamel surface characteristics by different microabrasion techniques

Pinheiro HA*1, Duarte CG1, Valente LL1, Isolan CP1, Munchow EA1, Moraes RR1.

1School of Dentistry, Federal University of Pelotas, RS.

Abstract

This study investigated the surface modification produced by different enamel microabrasion techniques. Enamel/dentin specimens were obtained from bovine incisors and allocated into four groups according to the microabrasion technique applied: Control – Enhance - finishing and polishing system (Dentsply); PUM+water – pumice/distilled water paste; PUM+acid – pumice /37% phosphoric acid (Condac 37, FGM) paste; and WRM – Whiteness RM – microabrasion product (FGM). Each group was subdivided according to the microabrasion time: 30, 60, 90, 120, and 150s (n=3). The surface roughness (Ra, µm) and the specimen change in mass (%) were evaluated before and after each treatment. Scanning electron microscopy (SEM) was used for surface topography analysis. Data were analyzed using two-way repeated measures ANOVA and Student-Newman-Keuls’s test (p<0.05). The specimens mass only slightly varied after each treatment, irrespective of the microabrasion time. While the Ra of the control and the PUM+acid groups was ot affected, groups PUM+water and WRM had lower Ra after 60/150s and 90/150s, respectively. The SEM images indicated that the surfaces were smoother and more regular with increased microabrasion times. PUM+acid and WRM created an enamel etched surface after 90s, although this effect was reduced after 150s. In conclusion, the microabrasion techniques influenced the surface characteristics of enamel.

Keywords

Enamel Microabrasion. Dental Enamel. Surface Properties.

70

Shelf-life simulation of self-etching adhesive systems

Oliveira HL*1, Cardoso AS2, Carreño NLV3, Gonini Jr A4, Piva E5

1 Post-graduate Program in Dentistry, Dental School, Federal University of Pelotas

2Department of Restorative Dentistry, Dental School, State University of Londrina 3Technology Development Center, Materials Engineer School, Federal University of Pelotas 4Department of Restorative Dentistry, Dental School, University of North Paraná 5Department of Restorative Dentistry, Dental School, Federal University of Pelotas

.

Abstract

The aim of this study was to evaluate the bond strength to dentin of self-etching adhesive systems subjected to controlled temperature and humidity conditions for up to 12 weeks. The materials tested by microtensile bond strength (µTBS) were Single Bond Universal™ (SBU) , AdheSE™ (ASE) and Clearfil SE Bond™ (CSB) by 60 human molars were used and the application of adhesives was performed immediately after the acquisition of materials and after 4 , 8 and 12 weeks of storage of them in the climate chamber ( 40° C and 50 % relative humidity) simulating shelf -life. The test was performed after storage of the sticks (n=20) in water for 24 hours . The μTSB values were tabulated and subjected to statistical Kruskal- Wallis test followed by Tukey test (α = 5 %). There was significant reduction in the μTSB of the ASE 8 week’s group (46,20 > 27,92). For SBU μTSB were significantly higher only in the 4 weeks group (4 weeks 90,90 > 24h 49,14 = 8 weeks 61,78 = 12 weeks 52,42), while CSB showed significant reduction according to the increase of the storage period (p<0.05). It can be concluded that the adhesive systems tested were sensitive to storage conditions, suggesting that the shelf-life simulation should be considered in future standards.

Keywords

Dentin-bonding agents. Product storage. Storage of substances, products and materials

71

Clinical efficacy of adhesive dental restorations of abfraction lesions: comparison of two restorative materials.

AUTHORS: Araújo IJS*¹, Medeiros FCD², Lima IPC³, Puppin-Rontani RM⁴.

Affiliation 1School of Dentistry, State University of Campinas, SP

²Department of Dentistry, State University of Rio Grande do Norte, RN

³Department of Dentistry, State University of Rio Grande do Norte, RN

⁴School of Dentistry, State University of Campinas, SP

Abstract

The restorative procedures of abfraction lesions must be accomplished using adhesive materials. The aim of this clinical study was to evaluate the efficacy of restoration abfraction lesion using different kinds of materials (modified glass ionomer cement and resin composite). To achieve a convenient sample were selected 30 patients which had at least two distinct premolars with abfraction lesions. Lesions were restored at the same clinical time, using a Z100 resin composite (3M ESPE) or a modified GIC Vitremer (3M ESPE). After the restorations, data collection was accomplished using a modified USPHS evaluation system. The criteria assessed were: marginal integrity, marginal discoloration, attrition, retention, secondary caries and sensitivity on baseline, 01 and 06 months after the restoration. Data were submitted to one-way Anova (p< 0.05) and Mann-Whitney’ (p< 0.05) tests. Results showed that both materials presented satisfactory clinical behavior in the period of 06 months. Significant difference was observed in the criteria: marginal integrity, marginal discoloration and wear, when the materials were individually analyzed for immediate and 06 months later. To Vitremer, the retention was satisfactory (p> 0.05). There was no significance to caries and sensitivity. Therefore, the GIC modified by resin showed a better clinical performance according to the evaluated criteria. It is suggested for further studies, the association of indirect assessment by photographs and models with clinical evaluation of restorations.

Keywords

Composite resin. Glass ionomer cement. Dental abfraction

72

Influence of contamination of hemostatic solutions on photopolymerizable resin cement

Araújo IS*1, Silva GR2, Prado CJ1, Raposo LHA1, Soares CJ2

¹Department of Occlusion, Fixed Prosthodontics, and Dental Materials, School of Dentistry, Federal University of Uberlandia, Uberlandia, MG, Brazil

²Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlandia, Uberlandia, MG, Brazil.

Abstract

Hemostatic agents are used in clinical practice to control bleeding and gingival fluid flow , which previously used the cementation of indirect restorations .

The objective of this study was to evaluate the bond strength of light-cured resin cement ( Variolink Veneer +1 ) to the surface by leucite reinforced

ceramic (n = 20) , and to verify the degree of conversion of the same ( n = 5 ) in relation to contamination hemostatic solutions. The specimens were

divided into: G1 - control; G2- aluminum chloride ( Hemostop ); G3 ferric sulfate ( ViscoStat ); G4- aluminum chloride ( ViscoStat clear) . After 24 h of

preparation of the specimens, the bond strength obtained by testing microshear and analysis of the degree of conversion was performed by

spectrophotometer. One-way ANOVA followed by Dunnett's test showed higher bond strength values for the control group when compared to the

experimental groups (p <.01). When comparing only the experimental groups, no significant differences between them (p = 0.083) were detected. For the

conversion degree followed by one-way ANOVA Dunnett's test showed a significant difference between G1 and G3 (p = 0.026), whereas the other groups

did not differ. By comparing the experimental groups, a significant difference was observed between G2 and G3 (p = 0.002) and between G3 and G4 (p =

0.004).It is concluded that contamination by hemostatic solutions promoted the reduction in bond strength of resin cement, but did not influence

significantly the degree of conversion of that. Keywords

Hemostatics, resin cements, FTIR

73

Bond strength of composite repairs involving tooth, composite and tooth/composite interfaces

Manso IS*1, Munchow EA1, Valente LL1, Isolan CP1, Moraes RR1.

1School of Dentistry, Federal University of Pelotas, RS.

Abstract

This study evaluated the bond strength (BS) of resin composite repairs to dentin (D), composite, and composite/dentin interfaces after different surface treatments. Forty bovine incisors were restored with CR. Each specimen was cut longitudinally, exposing the tooth/restoration interface to obtain halves, which were separated into four groups (n=20) according to the surface treatments: G1= no treatment (negative control); G2= 37% phosphoric acid (37 Condac, FGM) etching for 15s + adhesive (Single Bond 2, 3M ESPE); G3= application of silane (Dentsply); and G4= acid etching + silane + adhesive. Elastomer molds containing orifices (1.5mm diameter) were placed onto the surfaces and the orifices were filled with repair composite. The restorations were subjected to shear BS test. Failure modes were classified and bond strength analyzed using 2-way ANOVA and Tukey’s test (p<0.05). There was a significant interaction between surface treatment and substrate, with higher BS to dentin in G4, while BS to the other substrates was higher in G2 and G4. G1 showed low values of BS, but higher when applied on composite; G2 had lower dentin BS compared to other groups. G3 showed higher BS to composite, but low performance in the other substrates. G4 showed similar BS independent of the substrate. Failures were predominantly adhesive, irrespective of the surface treatment. The acid treatment followed by silane and adhesive showed the highest bond strength results in this study which could improve the repair potential of resin composite to dental and restorative substrates.

Keywords

Shear Strength, Composite resins, Silanes.

74

Synthesis and characterization of zinc oxide quantum dots

Garcia IMa*, Takimi Ab, Leitune VCBa, Samuel SMWa, Collares FMa

a Dental Materials Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil

b Laboratory of Ceramic Materials, School of Engineering, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil

Abstract

Zinc oxide has satisfactory characteristics for use in dental materials. Therefore, the aim of this study was to

synthesize and characterize zinc oxide quantum dots (ZnOQDs) for subsequent incorporation into dental

comonomer blends. Solutions of 0.0548g of zinc acetate dihydrate in 42mL of isopropyl alcohol and 0.0167g of

hydrated lithium hydroxide in 8mL of ethanol were ultrassonicated for complete dissolution of the reagents. The

solutions were cooled to 4°C and then they were mixed to 125mL of isopropyl alcohol at 4°C. The final solution was

heated in water bath at 40°C. After 5 minutes of heating, the solution was evaluated every 10 minutes by UV-Vis

spectroscopy to assess the particle diameter. The solution was stored at -20°C and it was analyzed 24 hours after

the synthesis by UV-Vis. In order to isolate the quantum dots, the final solution was washed through two cycles of

centrifugation with the addition of heptane and water, separately, to avoid the agglomeration of the particles.

After removing the supernatant, the precipitated was isolated and analyzed by FTIR-ATR-MIR. After 40 minutes of

heating of the solution, there was the stabilization of the particle diameter, which was 1.14nm on the day of the

synthesis and it was 1.16nm 24 hours after the synthesis. In the FTIR analysis, it was observed the presence of zinc

oxide through the peak in the region of 440cm-1. It was concluded that ZnOQDs can be synthesized by self-

organization of particles in a chemical reaction.

Zinc oxide; Spectroscopy, Fourier Transform Infrared; Dentistry.

75

Bond strength of a resin cement to Y-TZP and phase transformation after different sandblasting parameters.

Pozzobon JL*1, Missau T1, Druck CC1, Valandro LF1

1School of Dentistry, Federal University of Santa Maria, RS

Abstract

This study evaluated the effect of surface sandblasting parameters (distance and time) on the adhesion between YTZP ceramic and resin-based cements, as well as the t m phase transformation. Forty Y-TZP (In-Ceram YZ, Vita) blocks (4×4×3mm) were assigned into four groups(n=10), considering the parameters for zirconia surface sandblasting with 30µm silica-coated alumina particles (CoJet -Sand®):(T10D10) for 10 seconds and 10 mm in distance between the micro etcher hole and YTZP surface; (T10D20) for 10 seconds and 20 mm in distance; (T20D10) for 20 seconds and 10 mm of distance; (T20D20) for 20 seconds and 20 mm of distance. Specimens of composite resin (diameter= 3.25mm;height=3mm) were cemented to Y-TZP blocks using resin cement (Relyx ARC). All the specimens were subjected to aging (storage for 90 days and 10,000 thermal-cycles) and tested in shear. The tested specimens were analyzed under a stereomicroscope and under SEM. Phase transformation analysis (XDR) was also performed. Bond strength data were submitted to Student tests. For 20 seconds condition, the distance had statistical significance (p=0.0488), being 10 mm (8.5 4.2MPa) lower than 20 mm (12.1 3.4MPa). For 10 seconds condition, the distance was not statistical significance (p=0.3228; T10D10=6.4 4.6 MPa, T10D20=8.7 5.2MPa). The phase transformation ranged from 30.30% to 35.87%. The time factor was not significant, independent from the distance. It concludes the sandblasting with 20 mm may promote higher bond strength.

Keywords

Adhesion, Bond strength, Zirconia

76

In vitro study of the application of dental adhesives as modeler liquid of composite resin Porto JAS*1, Münchow EA1, Valente LL1, Isolan CP1, Piva E1, Pereira-Cenci T1, Cenci MS1

1 School of Dentistry, Federal University of Pelotas, RS

This study evaluated the effect of the presence of resin adhesive (RA) between composite resin (CR) layers on its physical properties. Schotchbond Multipurpose (bond, 3M ESPE) and Single Bond 2 (3M ESPE) were used as RAs, and Filtek Z350 (3M ESPE) as CR. Specimens containing RA were prepared by applying 3 layers of the adhesive between 4 layers of CR; adhesive-free specimens were used as control. Tests of water sorption (WS) and solubility (SL) (n=10), of microtensile cohesive strength (µCS; immediate and after 6 months of water storage), of flexural strength (FS) and flexural modulus (FM) (immediate and after 7 days of water storage) (n=5), and of translucency (TL) (immediate and after 24h, 7 days, and 2 months of water or red wine storage) (n=7) were performed. Data were analyzed by one way and two way ANOVA and Tukey’s test (p<0.05). SBMP showed lower WS and SL than the control. Immediate µCS was similar among groups, but lower after 6 months; control showed the lowest value. Immediate FS of SB was lower than the others, but it was maintained after 7 days of storage; SBMP and SB presented higher FS than control after storage. Immediate FM was similar among groups, and it was maintained for SBMP after storage; however, SBMP and SB showed higher FM than the control after storage. SBMP did not alter the TL of CR after storage in water or wine; in contrast, the control reduced TL in water and SB increased in wine. It can be concluded that the presence of RA between the layers of CR seems to increase the physic-mechanical stability of the material, being this effect more evident by using SBMP.

Keywords

Composite resins, Adhesives, Physical properties.

77

Two year clinical evaluation of self-etch adhesives in posterior restorations Conceição EN1, Rolla JN1, Melara R1, Feldens TT1, Silva FB2, Pereira Jr JCD1*.

Insert affiliation here 1School of Dentistry, Department of Conservative Dentistry, Federal University of Rio Grande do Sul, RS 2School of Dentistry, Federal University of Pelotas, RS

Abstract

This study investigated the clinical performance of composite restorations (Tetric Ceram /IvoclarVivadent) class I

made with an self-etch adhesive system (Adhese/ IvoclarVivadent) and a total-etch adhesive system with one-

bottle (Excite/ IvoclarVivadent). Twenty-three patients received two composite resin restorations with an adhesive

with each system. Clinical assessments were made at baseline, 12 and 24 months. The USPHS modified method

was used to evaluate the restorations on the marginal adaptation (A), anatomic form (F), marginal discoloration (D)

and postoperative sensitivity (SP). After two years, 95.7% of restorations were carried out with the Excite clinical

success for A, D and F and 100% for SP. The restorations made with Adhese had 100% success for A and SP and

95.7% for F and D. There was no significant difference between groups in different times of evaluation for all

criteria. After two years of clinical follow-up resin composite restorations made with an self-etch adhesive system

showed satisfactory success rates similar to the restorations made with an total-etch adhesive system.

Keywords

dentin bonding agents, clinical evaluation

78

Why zirconia-veneers are more prone to chipping?

Jikihara NA1, Tanaka CB1, Meira JBC*1.

1Departamento de Biomateriais e Biologia Oral, Faculdade de Odontologia, Universidade de São Paulo, SP.

Abstract

Studies have correlated high incidence of chipping on veneered zirconia to thermal stresses due to thermal gradient during

cooling. The aim of this study was to assess, using finite element analysis, the influence of the cooling rate on the temperature

gradient and thermal stresses of veneering porcelain on zirconia- and metal-based structures. Axisymmetric models were built

in disc and cylinder shape with 0.7 mm framework (zirconia - Z or metal – M) and 3.0 mm porcelain thickness. Two cooling rate

were performed: slow (SC - all stress generated on temperatures above Tg were relieved) and fast (FC - unrelaxed stresses).

Maximum (σ1-tensile) and minimum (σ3-compression) principal stresses in the porcelain layer were compared during

(transient) and after (residual) cooling. Graph of transient stresses (σ1 and σ3) showed that curves were fairly different when

the two cooling protocols were compared. For slow cooling, tensile and compressive peak occurred at 25°C, and for fast

cooling the peak occurred near Tg. Tensile and compressive residual stress were higher on zirconia-veneer. The discs and

cylinders stress peaks (in MPa) were: σ1= 26 and 29, σ3 = -44 and -47 (for SC-Z); σ1 = 24 and 26, σ3 = -40 and -41 (SC-M); σ1 = 17

and 18, σ3 =-10 and -11 (FC-Z); σ1 = 9, σ3 = -6 (FC-M).The lower risk of chipping on porcelain fused to metal would be related

with lower tensile residual stresses. Abrupt changes in porcelain properties during the glass transition temperature have

significant influence over the stresses generated during the cooling than to the thermal gradient.

Keywords

Dental Porcelain, Dental Crowns, Finite Element Analysis

Funding

FAPESP N° 2013/06988-8; FAPESP N°2012/15910-0

79

Crown vs. Composite for Post-retained Restorations: up to 47-month Trial

Jovito Adiel Skupien,1 Maximiliano Sérgio Cenci,1 Niek Opdam,2 Cees Kreulen,2 Marie-Charlotte

Huysmans,2 Tatiana Pereira-Cenci1

1Graduate Program in Dentistry, Federal University of Pelotas, Brazil. 2College of Dental Science, Radboud University, Nijmegen Medical Centre, The Netherlands.

Abstract

This randomized clinical trial compared the survival of composite resin restorations and metal-ceramic crowns of

endodontically treated teeth that received a glass fiber post. Fifty-six endodontically treated teeth severely

damaged but with at least one entire wall were randomly allocated into two groups according to the type of

coronal restoration: metal-ceramic crown or composite resin. A glass fiber post was previously cemented in all

teeth with regular or self-adhesive resin cement. Descriptive analysis through FDI clinical criteria was performed

and the longevity of restorations and teeth were analyzed using Kaplan-Meier statistics and log-rank tests. The

recall rate was 100% for a time up to 47 months. Eight composite restorations failed (all reparable). No tooth

failure was recorded. Log-rank test demonstrated a statistically significant difference for type of restoration

(p=0.003). No absolute failure was found in endodontically treated teeth restored with metal-ceramic crown or

composite resin; however, indirect restorations provided higher acceptable clinical performance and lower need

for reintervention.

Keywords

Composite resin; Crowns; Randomized clinical trial

Funding

The authors thank CAPES for financial support (Project CAPES/NUFFIC 026/11 and scholarship).

80

Influence of resin luting agents on the color stability of ceramic veneers

Almeida JR*, Schmitt GU, Kaizer MR, Boscato N1, Moraes RR1.

1School of Dentistry, Federal University of Pelotas, RS

Abstract

Resin luting agents have been demonstrating color variation after artificial aging. Therefore, this study investigated the effect of resin luting agents on the color stability of laminate veneers cemented to enamel and aged by thermalcycling. Bovine enamel discs were cemented to feldspathic ceramic discs with four resin-based luting agents (3M ESPE) – n=10: dual-cured cement - DC (RelyX ARC); light-cured cement - LC (RelyX Veneer); flowable composite resin - FR (Filtek Z350 Flow); pre-heated composite resin - HR (Filtek Z350 XT). Except for the composite resin, which was pre-heated for 30min at 60ºC, all materials were applied following the manufacturers’ instructions. CIEL*a*b* color parameters were measured 24h after cementation (baseline) and after every 2K of the total 20K thermalcycles (30s bath in water at 5±5 e 55±5oC), using a color spectrophotometer (Vita Easyshade). Dual cured cement had the greatest color variation both after 10K thermalcycles and after 20K thermalcycles when compared to the other luting agents (P<0.044). There were no significant differences among the other groups. All luting agents tested showed ΔE>3.3 after 20K thermalcycles. A significant variation in the CIE L*, a* and b* parameters was observed for all groups. The parameter b* for Dual-cured seems to have larger variation with time as compared with the other groups. The results of this study indicate that the aging and the luting agent can influence the color stability of laminate veneers cemented to enamel.

Keywords

Color. Laminate veneers. Resin cements.

81

Effectiveness of bleaching by contact and/or diffusion between bleaching gel and dental surface

Schwantz JK*1, Duarte CG1, Isolan CP1, Munchow EA1, Valente LL 1, Moraes RR1.

1School of Dentistry, Federal University of Pelotas, RS.

Abstract

This study evaluated the dental whitening effect by contact and/or diffusion of an in-office hydrogen peroxide bleaching agent. Forty bovine incisors were stained in coffee solution for seven days and CIELAB color coordinates were measured with a spectrophotometer (baseline). Before bleaching (Whiteness HP Blue 35%, FGM), the teeth were assigned into four groups according to the bleaching protocol (n=10). G1: each tooth had its vestibular surface divided into four quadrants, with only one quadrant receiving the bleaching gel, and CIELAB coordinates were measured for all quadrants and at the central area; G2: brackets were bonded at the central area of the tooth and bleaching gel around the brackets; G3: the entire surface of each tooth was bleached except for a central area to simulate the bracket space; and G4: the entire vestibular surface was bleached (control). CIELAB coordinates from specimens of G2, G3, and G4 were measured again only at the central tooth area. Data was analyzed by one-way ANOVA and Tukey’s test (p<0.05). The bleaching agent was able to externally diffuse over the tooth surfaces, regardless of being or not directly applied to the substrate. Improved whitening effect was observed closer to bleached areas. G2, G3, and G4 were statistically similar as regards the bleaching effectiveness. In conclusion, the bleaching effect was evident even without a direct contact of the gel with the tooth surface, suggesting that bleaching agents may diffuse over the surface of application.

Keywords

Tooth Bleaching. Orthodontic Brackets. Colorimetry.

82

Influence of different surface treatment in two types of ceramic composite resin with repairs in the shear resistance

Bettinelli JD*1, Giacomelli E1, Pagnoncelli RM1, Hirakata LM1

1 Faculdade de Odontologia, Pontifícia Universidade Católica do Rio Grande do Sul,

Porto Alegre, RS, Brasil

Abstract

The aim of this study was to determine the shear strength of repair in two types ceramic after different treatments . Forty ceramic discs were made of ceramics Noritake EX - 3 ( Group E) and forty discs were prepared by Noritake Cerabien ( Group C ) system, these were made from a metallic mold and included individually in the center of a ring polyvinyl chloride . The groups were randomly assigned . Group E1 and C1: laser application , E2 and C2 Group : etching with hydrofluoric acid 10 % , C3 and E3 Group : sandblasting with aluminum oxide , C4 and E4 Group : roughening with silicon carbide grain # 400 (control ) . All disks were standardized with ceramic roughening with silicon carbide grain # 400, applying a receiving layer of bonding agent for ceramic and an adhesive layer . In the center of the ceramic disc was made in a block microhybrid composite resin. Each group was maintained at 100 % humidity at 37 ° C for four weeks in the greenhouse culture. The shear strength tests used a Universal Testing Machine . Data were statistically analyzed with the aid of SPSS 17.0 , the Kolmogorov- Smirnov test and ANOVA . Sandblasting with aluminum oxide showed the highest values of shear strength at the interface between the composite resin and ceramic Cerabien ; and pottery EX3 , the largest values were those of the control group with the storage time of 4 weeks.

Keywords

Dental materials , ceramics , Shear

83

Evaluation of the cytotoxicity of different photoinitiators in two cell lines

Cá J, Chisini LA, Leal FB, Meereis CW, Conde MC, Carvalho RV, Ogliari FA, Demarco FF.

Department of Operative Dentistry, School of Dentistry, Federal University of Pelotas, RS

Abstract

This study evaluated the cytotoxicity of different photoinitiators in two cell lines in vitro. Eight photoinitiators were tested: camphorquinone (CQ); bisphenyl (2,4,6-trimethylbenzoyl)-oxide phosphine (BAPO); 1,3-benzodioxole (BDO); ethyl-dimethylamino benzoate (EDAB); diphenyl (2,4,6-trimethylbenzoyl)-oxide phosphine (TPO); diphenyliodonium hexafluorophosphate (DPI); piperonyl alcohol ( PA) and 1,3-diethyl-2-thiobarbituric acid (TBA). The cytotoxicity of the photoinitiators was tested in three concentrations: 25, 2.5 and 0.25 mM. A cell line of mouse embryo fibroblasts (3T3/NIH) and a cell line of normal human epithelial cells (keratinocytes-HaCaT) were used. The materials were 24h in contact with the cells and cytotoxicity was determined by MTT colorimetric assay. The absorbance value was determined in a spectrophotometer (540 nm). The data were tabulated and submitted to two-way analysis of variance and Tukey's test (p < 0.05). All tests were performed in triplicate. The results revealed a similar pattern of cytotoxicity to the two cells used. DPI was by far the most toxic photoinitiator in all tested concentrations and cell types. AP and TBA were less toxic than DPI, but more toxic than CQ, BAPO, BDO, EDAB and TPO. It can be concluded that most photoinitiators did not show cytotoxicity at the tested concentrations. However, DPI, AP and TBA showed different degrees of cytotoxicity, and DPI was the most toxic of all photoinitiators, independent of the concentration.

Keywords

Dental photoinitiators, cell culture techniques and tetrazolium salts.

84

Effect of specimen geometry on the flexural strength of dental porcelains after mechanical cycling

Fukushima KA*1, Borba M2, Dela Bona A2, Yoshimura HN3, Cesar PF1.

1School of Dentistry, Federal University of São Paulo, SP 21School of Dentistry, University of Passo Fundo, RS 3Federal University of ABC, SP

Abstract

To evaluate if the geometry of the specimen (discs vs bars) can affect the effect of mechanical cycling on the flexural strength.

Disks (12 x 2 mm) and bars (4 x 2 x 16mm) of two porcelains (VM7 and VM9, Vita) were prepared according to the manufacturers’ recommendations. The mechanical cycling was performed according to the following parameters: 45 N for 104 cycles, 2 Hz. The flexural strength test of cycled group and control group was carried out with a piston on three balls device for the disc-shaped specimens. The bar-shaped specimens were tested on a device of three point bending

The flexural strength values of VM7 for the control groups were 69.6 ± 15.2 and 61.1 ± 5.6 (MPa ± SD) for bars and disks, respectively, and for the cycled groups were 69.9 ± 10, 9 and 62.7 ± 9.3. The values found for VM9 control group were 57.6 ± 5.2 and 68.8 ± 9.4 for bars and disks, respectively, and for the cycled groups were 57.1 ± 3.6 and 62.7 ± 9.3.The results show that there was no significant change in resistance of the porcelain after any mechanical cycling, regardless of specimen geometry. However, for disc-shaped specimens the flexural strength values for VM7 were significantly higher than those of VM9, both before and after the mechanical cycling. Data were analysed with ANOVA (alpha=0.05).

The mechanical cycling did not affect the mechanical strength of the materials studied, regardless of the geometry. The disk geometry showed difference between the flexural strength values of the materials studied.

Keywords

Ceramics, dental porcelain

85

Effect of diferent root canal filling materials for primary teeth against mixed-species biofilms.

Pilownic KJ*1, Carvalho CN2, Shen Y2, Haapasalo M2, Romano AR1, Pappen FG1

1School of Dentistry, Federal University of Pelotas, Pelotas, RS, Brasil 2 School of Dentistry, University of British Columbia, Vancouver, BC, Canada

Abstract

The aim of this study was to acess the effects of root canal filling materials for primary teeth on mixed-species biofilms. The root filling materials used in this study were: Calcium hydroxide paste (CaOH2); CaOH paste associated with iodoform (Vitapex), CaOH2 paste (Calen) thickened with zinc oxide (ZO), iodoform; and Zinc oxide and eugenol (ZOE), iodoform and calcium hydroxide (CaOH2). Mixed-species biofilm samples were suspended in BHI and incubated using sterile hydroxyapatite disks as substrate. The disks were incubated in anaerobic conditions (AnaeroGen; OXOID, Hampshire, UK) for 21 days. The specimens were placed in contact with the tested materials for experimental periods of 7 and 30 days. The percentage of killed biofilm bacteria was determined by using LIVE/DEAD Baclight Stain (Molecular Probes, Europe BV) in confocal laser scanning microscopy. The cell viability ratios was performed using Imaris 5.0 software. The results were analyzed using ANOVA and Tukey tests (SPSS 17.0, SPSS Inc, Chicago, IL). In the control group, more than 93% of biofilm cells were viable within the experimental periods. There was a statistically significant difference between groups within the experimental times (F=73,073, P = 0,00). After 30 days, 49.59% of biofilm remained viable in contact with Vitapex and 31.41%, when Iodoform was used. ZOE cement allowed a viability ratio of 66.19% of biofilm. Calen + ZO and CaOH2 were the least effective materials against biofilms, since they left 73.73% and 81.44% of biofilms still viable after 30 days. In conclusion, the results of this study showed that Vitapex and Iodoform presented the best antimicrobial effect against mixed-species biofilms.

Keywords

Endodontics, Primary tooth,Biofilms

86

The effect of selants on white spot lesions formation adjacent to orthodontic brackets: a microcosm biofilm study Brauner KV*¹, Braz FG¹, Maske TT1,Van de Sande FH1, Cenci MS1

1School of Dentistry, Federal University of Pelotas, RS

Abstract

The aim of the study was to evaluate the effectiveness of two brands of occlusal sealants (with and without fluoride) in preventing white spot lesions formation adjacent to orthodontic brackets. Orthodontic brackets were centrally attached to forty bovine enamel disks and divided into 4 groups (n = 10): resin sealant without fluoride (SSF) and glass ionomer sealant with fluoride (SCF) around the brackets; topical application (2x/week) of 1.23% acidulated phosphate fluoride (ATF); and a control without any additional treatment. Artificial caries lesions were developed with a microcosm biofilm model, where the specimens were inoculated with human saliva and biofilms grown for 14 days under artificial saliva and intermittent 1% sucrose (6h daily). Enamel cross-sectional hardness was measured at the bracket margins and at 200μm of this interface and the results were expressed as means of integrated hardness loss (ΔS). Data was analyzed with ANOVA and Tukey’s test (α=0.05). Lower ΔS values adjacent to the brackets were found for both sealants when compared to the control (p <0.01). At 200μm of the interface was observed lower ΔS values for SSF and SCF when compared to the control (p <0.001) and similar to ATF. The conclusion of this study is that the use of sealants with and without fluoride was effective in reducing demineralization around orthodontic brackets under cariogenic challenges.

Keywords

Dental caries, sealants, fluoride

87

Thermo-mechanical properties of an experimental composite with remineralizing component

Felizardo KR*1, Lopes MB2, Mannocci F3, Feitosa VP4, Ogliari FA5, Gonini A6, Sauro S7,

Sinhoreti MAC8

Insert affiliation here 1School of Dentistry, State University of Campinas, Piracicaba Dental School, SP 2 School of Dentistry,University of North Parana, PR 3 School of Dentistry, KCL Dental Institute, UK 4 School of Dentistry, Federal University of Ceara, CE 5 School of Dentistry, Federal University of Pelotas, RS 6 School of Dentistry,University of North, PR 7 School of Dentistry,University of Cardenal Herrera,ES 8 School of Dentistry, State University of Campinas, Piracicaba Dental School, SP

Abstract

Demineralization and remineralization processes coexist in teeth during the entire life of an individual. In pathological

conditions, demineralization outweighs remineralization. Recently, experimental remineralizing resin-based materials

have been proposed as restorative materials to induce dentin remineralization. Therefore, the aim of this study was to

verify the thermo-mechanical property of an experimental remineralizing resin-based composite. This was formulated

and compared to a control group (same blend without active calcium-phosphates). The visco-elastic properties of the

experimental materials were characterized using dynamic mechanical thermal analysis with a cantilever-bending

clamp. Four specimens (n=4) of each group with 1 mm thick by 5 mm wide by 21 mm length were made and

photoactivated. In DMA, a sinusoidal stress was applied and the resultant strain was measured. The temperature varied

from −130 to 200o C with a ramping rate of 3oC/min at a frequency of 1 Hz. The properties measured under this

oscillating after 24h and 1 month. The experimental group (156.8 2.8) showed higher glass transition temperature (Tg)

in degrees centigrade with statistical difference after 24h compared to the control (149.3 2.5), however no statistical

differences were found after 1 month (experimental 131.1 2.1, control 132.5 0.5). The storage modulus showed no

differences between the groups independent of storage time. The remineralizing components could be incorporated to

the composite without adverse effect on the thermo-mechanical properties.

Keywords

Resin Composite, Calcium Phosphates and Tooth Remineralization

Funding

88

A systematic review on the factors associated with the retention of glass-fiber posts

Bianchini LD1*, Skupien JA2, Sarkis-Onofre R3, Cenci MS4, Moraes RR4, Pereira-Cenci T4.

1 Undergraduate Student, School of Dentistry, Federal University of Pelotas, RS, Brazil 2 Assistant Professor, School of Dentistry, UNIFRA, Santa Maria, RS, Brazil 3 PhD Student, Graduate Program in Dentistry, Federal University of Pelotas, RS, Brazil 4 Professor, Graduate Program in Dentistry, Federal University of Pelotas, RS, Brazil

Abstract

The objective of the study was to identify factors that can affect the retention of glass fiber posts (GFPs) to intra-radicular dentin based on in vitro studies that compared the bond strength (BS) of GFPs cemented with resin cements. Searches were carried out in Pubmed and Scopus until December 2013. Bond strength values and variables as type of tooth, presence of endodontic treatment, pretreatment of the post, type of bonding agent (if present), type of cement and mode of cement application were extracted from the 34 included studies. A linear regression model was used to evaluate the influence of these parameters on BS. The presence of endodontic treatment decreased the BS values in 22.7% considering the pooled data (p=0.013). For regular cement, cleaning the post increased BS when compared to silane application without cleaning (p=0.032). Applying the cement around the post and into root canal decreased the resistance compared to only around the post (p=0.02) or only into root canal (p=0.041), on the other hand, no difference was found for self-adhesive resin cement for the same comparisons (p=0.858 and p=0.067). Endodontic treatment, method of cement application, and post pretreatment are factors that might significantly affect the retention of glass-fiber posts into root canals. Self-adhesive resin cements were found to be less technique-sensitive to luting procedures as compared with regular resin cements.

Keywords

Review, Resin cements, Dental pins

89

Compression strength of conventional and resin- modified glass ionomer cements in contact with acidic solutions during the initial setting

Bohner LOL1 *, Catirse ABCEB1

1 Departament of Dental Materials and Prosthodontics, Faculty of Dentistry of Ribeirão Preto, University of São Paulo

The aim of this study was to evaluate the influence of acidic solutions when in contact with conventional Viddrion R (GIC) and resin- modified Vitremer (GIM) glass ionomer cements during the initial setting. Forty eight samples of each material were prepared and divided into two groups (n = 24), in accordance with the measured time (T1 and T2). Each group was divided into subgroups (n = 8), according to the acid solution (S1 - distilled water , S2 - orange juice, S3 - Coca - cola). The samples were submitted to 3 cycles of immersion in the respective solutions for 2 minutes each, in two different moments to each group: 1 hour (T1) and 24 hours (T2) after the material setting, and each one followed by repeated cycles, 4 and 8 hours after the initial immersion. The samples were stored in distilled water at 37 ° C and 24 hours after the last immersion, the compression strength test was performed. There was no statistical difference between the control group (S1 = 20.11) and acidic solutions (S2 = 25.83; S3 = 26.39) for both products. The GIM (35.81) presented a higher compressive strengthwhen compared with the GIC (12.41). The compressive strength decreased after 24h (T1 = 22.72, T2 = 16.93). The immersion in acid solutions during the initial setting increased the compressive strength of glass ionomer cements.

90

Evaluation of physico-chemical properties of white mta associated with herbal and propolis. Autores: Andreatta LM1, Cavenago BC1, Fernandes SL1, Zens MA1, Scotti CK1, Mondelli RFL1, Duarte MAH1.

Department of Operative Dentistry, Endodontics and Dental Materials, Faculty of Dentistry of Bauru, University of São Paulo, SP.

The aim of this study was to evaluate the physicochemical properties of white MTA when associated with Burdock extracts and propolis . Cements were divided into 4 groups , with white MTA manipulated with : aqueous extract of Burdock L ( G1 ) , 80 % distilled water + 20% propylene glycol extract of Burdock L ( G2 ), 80 % distilled water + 20 % of propylene glycol extract of propolis ( G3 ) and distilled water ( G4 ) . Evaluations of pH , calcium release , solubility and volumetric micro-computed tomography were performed . Data were statistically analyzed using the Kruskal- Wallis and Dunn, adopting a significance level of 5 %. Analyzing the data revealed that G2 significantly increased pH in the first 3 hours of the G1 and G4. G3 and G4 were used with the more caustic pH after three days. In other comparisons for pH no significant difference between groups was observed. The release of calcium was significantly higher in groups G3 , G2 and G1 with respect to distilled water within 3 hours. In 24 hours significantly lower than in other groups release occurred in G2 , and G3 in 7 days showed the highest release. On 3 and 15 days no statistically significant difference was found. For the solubility no statistically significant differences between groups. Although some physicochemical changes occur over time, the end 15 days all formulations were stable .

Keywords

Dental Pulp Capping, Propolis, , Lappa arctium

91

Different types of surface treatment on the bond between y-tzp and veneering porcelain

Yamamoto LT*1, Rodrigues VA1, Bottino MA1, Valandro LF1,2, Melo RM1

1 Departament of Dental Materials and Prosthodontics, School of Dentistry, Institut of Science and Technology – UNESP, São José dos Campos, SP.

2 Departament of Restorative Dentistry, Federal University of Santa Maria, Santa Maria, RS

Abstract

This study evaluated the influence of different surface treatments on YTZP ceramic on the bond strength between YTZP and porcelain. Forty YTZP ceramic blocks (VITA In Ceram YZ , ref. 40 x 19 x 15 mm ) (12 x 7.5 x 1.6 mm) were randomly divided into four groups (n = 10) according to the surface treatment: G1 - control (no treatment) ; G2 - Sandblasting with aluminum oxide particles coated with silica 30 μm (Rocatec Soft) and silane ; G3 - Glazing/ hydrofluoric acid ; G4 - Glazing /hydrofluoric acid/silane. After the treatments , porcelain cylinders (VITA VM9) with a diameter of 3 mm were applied to the zirconia , and properly sintered. The specimens were subjected to thermocycling (5 ° - 55 ° C) for 6,000 cycles and shear

test was performed. Data (MPa) were submitted to 1-way ANOVA and Tukey test(α = 0.05) and the

specimens submitted to failure analysis. ANOVA showed that the treatment had a significant influence on the shear strength (p <0.0001); Tukey test showed that G3 obtained the highest bond strength values (G1 - 10.1a ± 3.9; G2 - 12.5ab ± 4.6; G3 – 19.5c ± 3.1; G4 - 16.2bc ± 3.9) Failure analysis showed a predominance of adhesive failures (89.2%), a small percentage of mixed failures (10.8%), and no cohesive failures. It was concluded that vitrification of the ceramic surface infrastructure YTZP before applying porcelain may improve the adhesion between these two materials.

Keywords

Zirconia, Shear strength, Dental porcelain

92

Experimental resin primers for repair of composite resin restorations: formulation and bond strength evaluation

Valente LL*1, Manso IS1, Moraes RR1.

1School of Dentistry, Federal University of Pelotas, RS.

Abstract

The aim of this study was to investigate the effect of experimental resin primers on the shear bond strength (SBS) of composite resin repairs. Five primers containing silane, solvent, urethane dimethacrylate, 2-hydroxyethyl methacrylate, and an acidic monomer (GDMA-P) were formulated with varied silane content (mass %): P0=0%, P1=10%, P2=20%, P3=30%, and P4=40%. Composite resin blocks were aged by 5,000 thermal cycles, embedded in acrylic resin, and roughened with #600- and #1200-grit abrasive papers. Two coats of each primer were actively applied for 20s, the solvent was evaporated for 20s, and elastomer molds with cylindrical orifices (1.5mm diameter) were placed onto the surfaces. Light-activation was performed (20s), and the orifices were filled with composite resin (n=24). After 24h, the SBS test and carried out and failure modes were classified under 40× magnification. Data were analyzed using one-way ANOVA and Tukey’s test (p<0.05). SBS means (standard deviations) were: P0= 16.7(6.9)A; P1= 13.7(6.6)AB; P2= 11.8(6.3)AB; P3= 13.0(5.6)AB; and P4= 11.8(6.6)B. In the failure analysis, the results were: P0= 75%; P1= 66.7%; P2= 70.8%; P3= 79.2%; and P4= 70.8% of cohesive failures in the aged composite resin. In conclusion, the increase in the silane content seemed to affect negatively the ability of repairing composite resin restorations.

Keywords

Dental restoration repair. Shear Strength. Composite resins.

93

Indirect and direct cell viability in hydroxyapatite ceramic faced with osteoblastic cells Pires LA*1, Oliveira FA2, Oliveira RC2, Graeff MSZ2, Fortulan CA3, Meira CR3, Lisboa-Filho PN4, Borges AFS1

1Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, SP. 2Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, SP. 3Department of Mechanical Engineering, São Carlos School of Engineering, University of São Paulo, SP. 4Department of Physics, Bauru School of Sciences, São Paulo State University, SP.

Abstract

The hydroxyapatite has similar mineral composition and structure bone phase. The aim of this study is to assess cell viability in experimental ceramic hydroxyapatite of bovin origin e compared with two types of commercial zirconium and titanium alloy commercially pure, to be used in the future as material base for dental implants. The in vitro evaluation was performed through tests in which MC3T3-E1 cultured murine cells lineage were placed in indirect and direct contact with these materials. Indirect viability (n = 8): MTT assay and Crystal Violet tests were performed in duplicate and were analyzed the absorbances after 24, 48 and 72 hours (Elisa reader). Direct viability (n = 5): cells were plated directly on disc surfaces, fixed in vapor of osmium tetroxide 2% after 24 and 48 hours, followed by metallization for analysis in Scanning Electron Microscope (SEM). The results for indirect viability of both, the MTT assay as in Crystal Violet according to the control group, all groups showed satisfactory results, being the ceramic hydroxyapatite to the control group level or above, demonstrating not be a cytotoxic material. Starting from SEM images generated in the direct viability test, was verified that cell adhesion in both periods and after 48 hours revealed a cellular proliferation on the surfaces of materials. Therefore, it can be affirmed that the hydroxyapatite ceramic was presented as a biocompatible material.

Keywords

Durapatite, cell survival, biocompatible materials.

94

Effect of three variables on fracture resistance of endodontically treated direct-restored premolars

Brondani LP*, Skupien JA, Pereira-Cenci T, Kreulen C, Huysmans MC, Opdam N

School of Dentistry, Federal University of Pelotas, RS

Abstract

The aim of this study was to evaluate the influence of remaining cusp, remaining cervical tissue, and post, on fracture resistance and fracture type of restored endodontically treated teeth (ETT). One hundred extracted upper premolars were endodontically treated and randomly allocated into 10 experimental groups (n=10). The groups were divided according to the following variables: cavity design (remaining cervical tissue and cusp), presence/absence of post and controls (with and without fatigue). After specimen’s preparation, a composite restoration was built up and then submitted to 6,000 thermal cycles followed by 5,000 cycles of mechanical dynamic loading. Thereafter, ramped load until fracture was performed. The data was analyzed by ANOVA and Tukey’s post hoc tests. Linear and logistic regressions were used to investigate the influence of variables. There was no restorations fails before ramped loading. The variables cervical outline and post significantly affected (p < 0.05) fracture resistance, while no difference on the resistance was found if remaining cusp was present (p = 0.091). The chance of catastrophic failure increased (OR = 3.17) if a post was present. The presence of remaining cervical tissue and post increased the fracture resistance of endodontically treated restored premolars; however, a post increased the chance of a catastrophic failure to occur.

Keywords

Composite resin; Fibre post; Fracture resistance

95

Physical and mechanical properties of a new periodontal dressing

Conceição LD*1, Lindemann A2, Lund RG3, Piva E4, Ogliari F5, Leite FRM6.

1School of Dentistry, Federal University of Pelotas, RS 2School of Dentistry, Federal University of Pelotas, RS 3School of Dentistry, Federal University of Pelotas, RS 4School of Dentistry, Federal University of Pelotas, RS 5School of Materials Engineering, Federal University of Pelotas, RS 6School of Dentistry, Federal University of Pelotas, RS

Abstract

The aim of this study was to develop a periodontal dressing (PD) based on methacrylate monomers (Exothane™-Gexp) and

characterize the physical and mecanical properties comparing with Periobond™ (Gperio) and Barricaid™ (Gbar) (controls).

Water sorption (WS) and solubility (SL), Ultimate Tensile Strength (UTS), and Shore Hardness (A) were tested. For WS and WBS

specimens (n=10) were placed in desiccator at 37◦C until a constant mass was obtained (m1) and the volume measured.

Subsequently they were immersed in distilled water until no alteration in mass was detected (m2). Samples were again placed

in desiccator until obtain a constant mass (m3). UTS samples (n=15) were tested in tension using a universal testing machine at

crosshead speed of 0.5 mm/min (MPa). The Shore Hardness samples (n=5) were measured by a Durometer. The statistical

analysis was performed by ANOVA and Kruskall-Wallis/Mann-Whitney (P<0.05). WS test showed statistical difference between

Gperio (426.0±240.9) and Gexp (46.6±12.9) and Gperio and Gbar (83.5±29.8) (P<0.001). There was no difference when

comparing Gbar and Gexp. Regarding SL no statistical difference was seen between groups. There were no differences

between the median values of Gexp (5.33) and Gbar (4.21) (P=0.125) for UTS. Hardness of the Gexp (92.70±0.68) and Gbar

(81.00±1.18) was statistically significant (P=<0.001).The results showed that photo cured PD made with Exothane™ fulfill the

physical and mechanical biological requisites of a material for this purpose.

Keywords

Periodontal dressings. Dental materials. Elastomers

96

Effect of diamond polishing pastes on surface characteristics of composite resins

Rosa LL*1, Fonseca A2, Valente LL1, Isolan CP1, Munchow EA1, Schneider LF2, Moraes RR1.

1School of Dentistry, Federal University of Pelotas, RS. 2School of Dentistry, Federal Fluminense University of Niteroi, RJ.

Abstract

This study investigated the influence of diamond-based polishing pastes (PPs) on the surface roughness (Ra, μm), water contact angle (θ, o), and gloss (GU) of two composite resins: microhybrid (Opallis, FGM) and nanofilled (Filtek Z350, 3M ESPE). Forty cured disc-shaped specimens of each composite were divided into two subgroups (n=20) according to the PPs tested (FGM): Diamond AC I/II (PP-AC) or Diamond Universal (PP-U). The specimens were polished using alumina abrasive discs, abrasive rubber, and a final polish was carried out using felt disc and the respective PPs. Ra and θ were measured before and after polishing, while gloss was measured only after polishing with the PPs. Data were analyzed using one-way or two-way ANOVA and Student-Newman-Keuls’ test (p<0.05). The composite influenced the performance of the PPs only as regards Ra (p=0.003); while Z350 had a smoother surface after application of either PPs, only PP-U reduced the Ra of Opallis. PP-AC resulted in lower θ for both materials (57.6° and 50.1° for Opallis and Z350), whereas PP-U resulted in increased θ values (64.5° and 60.9° for Opallis and Z350). Z350 polished with PP-AC and PP-U respectively had almost three times and two times higher gloss than Opallis. In conclusion, the surface characteristics after polishing with PP were material dependent. PP-U seems to contribute for reduction of Ra irrespective of the composite tested, also leading to improved gloss and higher θ when compared with PP-AC.

Keywords

Surface Properties. Hydrophobia. Composite Resins.

97

Strains analysis around implants after fixation of ceramic veneered superstructure Oliveira-Neto LA1*, M.D. COSTA SR.2, M.L. ALBARATIN2, , V.C. BIANCO2, E.A.C. SOUZA3, J.H. RUBO4

Affiliation 1 School of Dentistry, Federal University of Sergipe, Aracaju, Sergipe, Brazil

2 Prosthodontics, Bauru School of Dentistry, University of Sao Paulo, Bauru, Brazil,

3 Department of mechanical engineering, Universidade Estadual Paulista - UNESP, Bauru, Brazil,

4 University of Sao Paulo, Bauru, Sao Paulo, Brazil

Abstract

Passive fit and stability have become the most important prerequisites during the choice of materials and techniques to implant-supported prostheses. This study aims to analise the strain development in abutments and simulated bone tissue around dental implants during screw retention of three-unit fixed partial superstructure in the condition as cast and after ceramic veneering. Experimental model based on homogeneous polyurethane with mechanical properties similar to those of trabecular bone was created with two external hexagon implants parallel to each other, provided with multi-unit abutments. For each, abutment surface received three equidistant strain gauges and the experimental block received upper surface four strain gauges, positioned on the mesial, distal, buccal and lingual aspects adjacent to the implants. The tests were performed screwing the specimens on the abutment using an electronic torque device with 10 Ncm maximum force. The amount of strain measured were analyzed by 1-way ANOVA. Strain gauges readings were made in two moments with abutment and polyurethane mean deformation, respectively: 1) as casted superstructure (146µɛ and 280µɛ) and 2) superstructure after ceramic veneering (197µɛ and 359µɛ). As conclusion, was found that ceramic veneering increased strain levels in abutment and simulated bone tissue around dental implants, during screw retention of three-unit fixed partial superstructure.

Keywords

Dental implants

Implant-supported prostheses

98

Physical and biological properties of an experimental mta-based root canal filling material for primary teeth

Pilownic KJ1, Almeida LHS1*, Romano AR1, Wang Z2, Shen Y2, Haapasalo M2, Pappen FG1

Insert affiliation here 1School of Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil. 2 School of Dentistry, University of British Columbia, Vancouver, Canada.

Abstract

This study evaluated the pH, the radiopacity and the cytotoxicity of an experimental MTA-based root canal filling material for primary teeth. Other materials were also evaluated: Vitapex; Zinc oxide and eugenol (ZOE); and Calen paste thickened with zinc oxide (ZO). The measurement of pH was carried out in deionized water, in periods between 1 hour and 30 days. The radiopacity of the materials was compared with a standardized aluminum scale measuring between 0,5 and 5 mm, using a digital sensor, standardized focal length and exposure time. Cell viability was evaluated, in human gingival fibroblasts exposed to the materials for 1, 3 and 7 days. The CellTiter 96Assay kit, for MTT test was used. All the tests were performed in triplicate, and data were analyzed by ANOVA and Tukey tests. Experimental MTA presented 3,28 mmAl in the radiopacity assay. This value is in accordance with ISO, but it was statistically lower than the values found for the other evaluated materials. The pH of experimental MTA was similar to Calen thickened with ZO, and it ranged from 12,8 to 11,2 in experimental periods. The incubation time and the concentration of the material extract did not affect the cytotoxicity of the materials. Only experimental MTA showed higher levels of cytotoxicity after 7 days of incubation. A higher percentage of cell viability was observed when Vitapex was used. ZOE was the most cytotoxic evaluated material. In conclusion, experimental MTA presented acceptable properties for its use as root canal filling material for primary teeth. However, it presented lower radiopacity than the other evaluated material and higher citotoxicity in comparison to Vitapex.

Keywords

Endodontics, primary tooth; physical properties; cytotoxicity

99

Effectiveness of fluoride to control erosive demineralization . An in vitro study

Salas MMS1*, Alcázar JCB1, Tarquinio SC2, Demarco FF2.

Affiliation

1 PhD student . Postgraduate program of Dentistry , Federal University of Pelotas

2 Professor. Postgraduate program of Dentistry , Federal University of Pelotas

Abstract

The aim of the study was to analyse the effectiveness of fluoride to control enamel demineralization produce by erosion. Forty five bovine incisors were used . The enamel surfaces were smoothed by grounded (crescent granulation : 200, 400, 600 , 1200 , 2000). Three measures of enamel hardness were previously determined. The force applied was 50grams for 10 seconds. The samples were randomly divided into group A ( fluoride varnish) , group B ( fluoride gel ) , Group C (control ) . The handling of the materials followed the manufacturer's instructions . The samples were covered, except the enamel surface, with nail resin varnish and immersed in carbonated beverage (pH 2.3 ) for five minutes six times a day for 15 days. Teeth were stored in artificial saliva at 37 ° C. Hardness measurements were obtained . Statistical analysis was using one-way analysis of variance (ANOVA) and the Holm Sidack test, with a significance level of 5 % ( p < 0.005 ) . Enamel surfaces after erosion challenge had significantly lower hardness ( p < 0.001 ) . Hardness measures were lower after the erosive challenge on the fluoride gel group compared with control ( p < 0.001 ) and was not different from the control surfaces of erosive demineralization ( p = 0.5 ). In the varnish group , no significant difference compared to control without erosion ( p = 0.25 ) was observed but there was a significant difference with the hardness of the surfaces with only erosion ( p > 0.05 ). The use of fluoride varnish on the surface maintained the hardness of enamel after the erosive challenge .

Keywords. Tooth Erosion , Fluoride , Hardness

100

Influence of dentin surface treatments on the bond strength to resin cements

Silva MF*1, Munchow EA1, Valente LL1, Isolan CP1, Moraes RR1.

1School of Dentistry, Federal University of Pelotas, RS.

Abstract

This study investigated the bond strength between resin cements and dentin after different surface treatments. Forty bovine incisors were prepared and dentin was exposed; next, they were thermal cycled using 2,000 cycles and assigned into four groups (n=10) according to the surface treatment and/or resin cement: G1 (negative control) – no surface treatment + self-adhesive resin cement (U200, 3M ESPE); G2 – roughening with diamond bur #3168F (KG Sorensen) + U200; G3 – etching with 37% phosphoric acid (Condac 37, FGM) + U200; and G4 (positive control) – etching with 37% phosphoric acid + adhesive (Single Bond 2, 3M ESPE) + regular resin cement (RelyX ARC, 3M ESPE). After 24h, the specimens were submitted to a shear bond strength test on a mechanical testing machine. Failure modes were classified under magnification. Data were analyzed using Kruskal-Wallis test (p<0.05). The medians (maxima-minina) were: G1= 8.0 (16.0-5.4)A; G2= 2.8 (5.0-2.4)B; G3= 10.0 (19.8-4.6)A; and G4= 7.2 (12.8-4.3)A. Failure modes were predominantly adhesive. In conclusion, the type of surface treatment influenced the bond strength between dentin and resin cements; pre-roughening the substrate resulted decreased bonding ability. In addition, the type of resin cement (self-adhesive or regular) had a minor effect on the dentin bonds.

Keywords

Dental restoration repair. Resin cements. Shear Strength.

101

Ion release of resin-based materials containing different phases of calcium phosphate Rodrigues MC*1, Natale LC1, Arana-Chaves VE1, Braga RR1.

1 University of São Paulo, School of Dentistry, Department of Biomaterials and Oral Biology, São Paulo, SP, Brazil

Abstract

The objective of the study was to evaluate ion release from resin-based materials containing different phases of calcium phosphate (CaP). Commercial particles of ACP (amorphous calcium phosphate), DCPA (dicalcium phosphate anhydrous) , DCPD (dicalcium phosphate dihydrate) and β-TCP (beta-tricalcium phosphate) were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) , dynamic light scattering (DLS) and adsorption isotherms (BET method) . The composites were manipulated by addition of CaP particles (20% vol) in an organic matrix containing BisGMA and TEGDMA and these composites were evaluated for degree of conversion (GC) and ion release (IR) under pH 7 and 5.5 for 28 days. Data were analyzed to ANOVA/Tukey test (alpha = 0.05). The crystalline structure of DCPA, DCPD and TCP were confirmed by XRD, as well as the ACP amorphous nature. TEM revealed different morphologies, TCP and DCPD showed the major agglomerates. The surface area of the ACP was significantly higher than the others CaP. All composites showed similar GC. The composite containing ACP showed higher IR than others composites which similar IR amounts of Ca ions and P, in most cases. The pH did not significantly affect IR, which decreases between 7 and 21 days and levels at 28 days were similar to 14 days. ACP higher ion release can be ascribed to its high surface area. The other CaP, even with different characteristics, had similar results in the ions release.

Keywords

calcium phosphates, composites, ion release

Funding

Fapesp: 2012/04532-4

CNPq: 142960/2011-0

102

Effect of cementation protocol on push-out bond strength of fiber posts to root canal

Borges MG*1, Casselli DSM2, Faria-e-Silva AL3, Menezes MS1.

1 Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlandia, Uberlandia, MG, Brazil. 2 Department of Dentistry, Federal University of Ceará, Sobral, CE, Brazil.

3 Department of Dentistry, Federal University of Sergipe, Aracaju, SE, Brazil.

Abstract

The aim of this study was to evaluate the effect of adhesive protocol on the retention of glass-fiber posts luted into root canals. Thirty bovine incisors were endodontically treated and 9-mm-deep post holes were prepared. Fiber posts were luted using one of following protocols (n = 10): SB – Single Bond (3 M ESPE) with regular resin cement RelyX ARC (3 M ESPE); SBMP – Scotchbond Multipurpose Plus (3 M ESPE) associated with RelyX ARC; or UNI – the self-adhesive resin cement RelyX Unicem (3 M ESPE). After cementation, root/post specimens were transversally sectioned into 1-mm-thick slices, which were submitted to push-out testing in a mechanical testing machine. Bond strength data were analyzed by ANOVA (α = 0.05). There was no statistical difference between the adhesive protocols evaluated. Considering that the adhesive protocols evaluated showed similar bond strength values, simpler protocols must be preferable to lute fiber posts to root canal.

Keywords

Dental bonding; Post and core technique; Resin cements.

FUNCAP 0031-00114.01.00/10.

103

In vitro longitudinal evaluation of repaired aged composite resin

Souza MO*, Leitune VCB, Samuel SMW, Collares FM

Department of Conservative Dentistry, School of Dentistry, Universidade Federal do Rio Grande do Sul, RS, Brazil.

The study aims to evaluate in vitro the influence of surface treatment of aged resin submitted a repair. 56 cylinders of resin composite were made and divided into 7 groups according to the surface treatment. Stored in artificial saliva and evaluated at 24h, after 1 year of aging of the cylinder, then get to the repair, after 1 year of aging of already aged cylinder repaired and after 1 year of storage cylinder that suffered the repair immediately. G1, blasted with aluminum oxide (Al2O3), G2, Al2O3 and silane, G3, Al2O3 and adhesive; G4, application of hydrofluoric acid, 9,6% (HF), G5 HF and silane and G6, HF and adhesive. In the control group (G7), the resin cylinders received no treatment. After surface treatment, composite repairs were performed in the cylinders and then sectioned into beans and submitted to microtensile bond strength, calculated in MPa. Data analysis was performed using multiple linear regression model. The aging of restoration reduce in approximately 3.0 MPa the bond strength. Similarly, the aging of repair reduce 4.0 MPa. However, the surface treatment with Al2O3 increases the bond strength in 20.4MPa. No statistically significant differences were found to HF application. In relation coating applied, adhesive showed increase in bond strength of 12.17 MPa, being major than silanization (4.4 MPa). In this model, the use of a “control group” was regarded as the reference group. We conclude that aging of the composite influenced the tensile bond strength of repair, and blasting with aluminum oxide followed by application of adhesive showed the best result.

Composite Resins. Dental Restoration Repair.

104

Longitudinal clinical evaluation of composite resin restorations flow type of low shrinkage in posterior teeth Fagundes LO¹, Goulart M¹, Totti M¹*, Erhardt MC¹, Coelho-de-Souza FH¹

Insert affiliation here 1School of Dentistry, Federal University of Rio Grande do Sul, RS

Abstract

The aim of this split-mouth randomized clinical trial was to evaluate the clinical behavior of composite restorations in posterior teeth type I and II done with two restorative systems, one being of low shrinkage. Seventeen patients requiring at least two restorations in posterior teeth were selected to participate in the study. The causes for the indication of the restorations were: replacement of defective amalgam restoration or composite and/or caries. Each patient received two restorations. Randomly, a cavity was restored with Esthet-X HD composite resin (control group) and the other restored with Esthet-X HD associated with Surefil SDR Flow composite resins (experimental group). After a period of 6 months, the quality of restoration was evaluated by two examiners previously calibrated, through a modification of the method USPHS and by the method FDI. Data were statistically analyzed by nonparametric Mann-Whitney (p<0,05), and intra-and inter-observer evaluated through test Kappa. The reproducibility inter-examiner was 0.85 and 0.8, respectively. No statistically significant differences were found between the experimental and control groups, regardless of the evaluation criteria. The use of low shrinkage composite resin (Surefil SDR Flow) as a base material for restoring posterior teeth showed no change in patterns clinical and radiographic follow-up at six months.

Keywords

Restoration. Polymerization Shrinkage. Composite Resins.

105

Effects of the brush simulation with fluoride and whitening dentifrices on the unbleached and bleached enamel. Analysis of surface roughness Silva MAB*1, Vitti RP2, Neto CFL3, Reis JIL1, Tonholo J3.

Filiação 1Departamento de Odontologia Restauradora, Faculdade de Odontologia da Universidade Federal de Alagoas, AL 2Departamento de Materiais Dentários, Faculdade de Odontologia de Piracicaba (UNICAMP),SP 3Departamento de Química e Biotecnologia, Universidade Federal de Alagoas, AL

Abstract

The aim of this study was to evaluate in vitro the effect of the brush simulation with fluoride and whitening on the surface roughness of bleached (Carbamide peroxide 10%) and unbleached enamel. Fifty sound bovine incisive were allocated in five equally sized-groups (n=10) G1- control (brushed with distilled water without dentifrice); G2 – Oral-B Pro healthy (Flouride dentifrice); G3 – Oral-B 3D White Brilliant Fresh (Whitening dentifrice); G4- Opalescence (Carbamide peroxide 10%) plus brushing with fluoride dentifrice, G5- Opalescence (Carbamide peroxide 10%) plus brushing with whitening dentifrice. The samples were submitted to a 30000 mechanical cycles of simulated brushing and the whitening gel was applied according the manufactures instructions. The surface roughness was analyzed by mean a rugosimeter before and after the brushing simulation. The Kruskall-Wallis, one way-Anova and Mann-Whitney tests were used to perform the statistical analysis(p<0.05). The data showed a significant statistical differences among the groups, and a increase of the surface roughness were detect in all the groups after the brushing simulation (p <0.05). At the baseline values, all groups showed statistically similar Ra values (p > 0.05) The brushing simulation with whitening dentifrices on bleached enamel increases the surface roughness of the enamel.

Descriptors

Tooth whitening; brushing; dentifrices

Financial support

106

Degree of conversion and bond strength of experimental self-adhering flowable composites formulated with different photoinitiators Bertolo MVL*1, Monteiro AA2, Sodré CS2, Vitti RP1, Sinhoreti MAC1, Schneider LFJ2,3.

1Dental Materials, Piracicaba Dental School, University of Campinas, Piracicaba, SP. 2Dental Materials Biotechnology Laboratory, School of Dentistry, Veiga de Almeida University, Rio de Janeiro, RJ. 3School of Dentistry, Fluminense Federal University, Niterói, RJ.

Abstract

The aim of this study was to determine the degree of conversion (DC) and bond strength (BS) of flowable composites formulated with self-adhesive monomers (2MP and 4-META). Three monomers series were formulated: BisGMA/TEGDMA (50/50 wt%, control), BisGMA/TEGDMA/2MP and BisGMA/TEGDMA/4-META (25/25/50 wt% for both). To these monomers were added the following photoinitiators: camphorquinone (CQ) + amine (EDMAB) monoacyl phosphine oxide (TPO), bisacyl phosphine oxide (BAPO), CQ+EDMAB+TPO and CQ+EDMAB+BAPO. To these mixtures was added silicon dioxide (40 wt%). Photoactivation was performed using a LED (Bluephase 2 , Ivoclar) for 20 s and 1200 mW/cm2. GC was evaluated by FTIR-ATR. For BS (dry and wet dentin), bovine teeth were restored using only materials formulated with the TPO system. The control group was applied after the use of the adhesive system Single Bond Universal (3M ESPE). The teeth were sectioned into sticks, stored in distilled water at 37ºC for 24 h and submitted to the tensile test using an universal testing machine (EZ Test, Shimadzu). The results of GC and BS were submitted to two-way ANOVA and Tukey test (p<.05). For the control and 4-META groups, TPO showed higher GC. To 2MP, BAPO and CQ+EDMAB had higher GC. The 2MP monomer had higher GC independent of photoinitiators. Highest value of RU was found in the control group in both dentine. It can be conclude that TPO had better GC to composites with 4-META, as BAPO was more efficient for composites with 2MP. Composites containing 4-META and 2MP were able to promote adhesion to dry and wet dentin.

Keywords

Dental Materials, Tensile Strength, Dental Photoinitiators

Funding

FAPERJ, 2012.

107

Influence of irradiance and exposure time on the degree of conversion and mechanical properties of a silorane composite

Poskus LT*1, Gonzalez MR2, Prado NAS2, Sampaio Filho HR2, Perez CR2.

Insert affiliation here 1School of Dentistry, Federal University of the State of Rio de Janeiro, RJ 2School of Dentistry, University of the the State of Rio de Janeiro, RJ

Abstract

The aim of this study is to evaluate the influence of different combinations of irradiance and exposure time for a given radiant exposure on the degree of conversion (DC) and on the mechanical properties of two resin composites: Filtek Z250 and Filtek P90 LS (3M ESPE). Materials and Methods: The following curing protocols were used: Standard irradiance: 400 mW/cm2 for 60 s; Medium irradiance: 700 mW/cm2 for 34 s and High irradiance: 950 mW/cm2 for 26 s. The DC was measured using Fourier Transform Infrared spectroscopy. Each specimen was submitted to five indentations to evaluate the Knoop microhardness (KHN). The flexural strength (FS) was obtained from the three-point bending test. Cylindrical specimens were prepared for the Diametral tensile strength (DTS) test. Statistical analysis: Data were evaluated using two-way ANOVA and Tukey’s test (p = 0.05). Results: DC and DTS were not influenced by the different curing protocols. For P90, the medium irradiance showed higher values of KHN than the standard irradiance. For Z250, the high irradiance showed higher values of FS than the standard irradiance. Conclusion: The influence of the different combinations of irradiance and exposure time depends on the resin composite as well as the specifically evaluated mechanical property.

Keywords

Composite resin, Polymerization, Hardness.

108

Voltammetric analysis of oxygen release by bleaching gels

Moreno MBP*1, Ribeiro WF2, Lima GBV3, Carvalho FG4, Montenegro RV4, Correr-Sobrinho L1, Carlo HL4

Insert affiliation here 1School of Dentistry, University of Campinas, Piracicaba, SP. 2 Federal University of Paraíba, PB. 3 Graduated in Dentistry, Federal University of Paraíba, PB. 4School of Dentistry, Federal University of Paraíba, PB.

Abstract

The dissolution rate of hydrogen peroxide (HP) influences dental bleaching. The aim of this study was to analyze commercial home and in-office bleaching gels’ oxygen release, using the voltammetric method. The analysis was performed on a potentiostat coupled to a polarographic module using a Ag/AgCl – KCl as reference electrode, platinum wire as counter electrode and glassy carbon electrode as working electrode. Whiteness HP (35%) and White Class (7.5%) gels (FGM, Brazil) were used. The application was simulated in electrochemical cell, monitoring the HP signal for 2 hours, recording readings every 5 minutes. To verify the light effectiveness on HP 35% decomposition, two experiments were performed. First, LED-light was applied during the first 5 minutes. In the second, light was not used. The results were qualitatively analyzed. On 7,5% gel, O2 release and HP decomposition were higher in the first 60 minutes of the analysis, stabilizing after this period and standing close to zero after 135 minutes. For the 35% gel, when the LED-light was applied, O2 was detected as early as 5 minutes and stabilization of HP decomposition started after 65 minutes. In the analysis without employing light, the presence of O2 was observed just after 35 minutes and stabilization occurred after 65 minutes. Light employment accelerated the decomposition chemical reaction of 35% hydrogen peroxide. 6% hydrogen peroxide presented decomposition stabilization after 60 minutes from the beginning of the analysis.

Keywords

Tooth Bleaching, Hydrogen Peroxide, Oxygen

109

Evaluation of phenyl-propanedione on yellowing and physical-mechanical properties of experimental composites photo-activated by different curing units

Sinhoreti MAC*1, Oliveira DCRS1, Brandt WC2, Souza-Junior EJ1, Correr Sobrinho L1

Inserir aqui filiação 1Department of Restorative Dentistry, Dental Materials Area, Piracicaba Dental School, Campinas State University, UNICAMP. 2 Dentistry School, Santo Amaro University, UNISA, SP.

Abstract

The aim of this study was to evaluate the influence of phenyl-propanedione on yellowing and physical-mechanical properties of experimental resin composites photo-activated by different light curing units (LCUs). Three experimental resin composites were mechanically blended using a centrifugal mixing device with the same organic matrix: 29 wt % Bis-GMA, 32.5 wt % UDMA, 32.5 wt %, Bis-EMA, 6 wt % TEGDMA and added 13 wt % 0.04 μm fumed silica and 52 wt % 0.7 μm BaBSiO2. Different photo-initiator systems were added to each composite: CQ/DMAEMA, PPD/DMAEMA or PPD/CQ/DMAEMA. The physical-mechanical properties evaluated were the degree of conversion (DC), flexural strength (FS), Young’s modulus (YM), Knoop hardness (KNH), crosslinking density (CLD) and yellowing (Y) (n=10). All samples were light cured with one of the following LCUs: a halogen lamp (XL 2500, 3M ESPE) or a LED (Valo, Ultradent or Radii, SDI) with 16 J. The results were analysed by two-way ANOVA and Tukey test (p=0.05). No statistical difference was found between the different photo-initiator systems to KNH, CLS, FS and YM properties (p=0.05). PPD/CQ association showed the higher DC values compared to CQ and PPD isolated systems (p=0.05). Y values were uppermost to the [CQ] compared to the PPD systems. Thus, is possible to conclude that the PPD promoted similar physical-mechanical properties and less yellowing compared to the CQ; The CQ/PPD association showed superior physical-mechanical properties compared to CQ and PPD isolated systems.

Descritors

Composites; Polimerization; Mechanical properties

110

Effect of nano filler particles on degree of conversion and potential color change of resin-based composites Rocha MG*¹,Oliveira DCRS¹, Sobrinho LC¹, Sinhoreti MAC¹, Ferracane JL², Correr AB¹

Insert affiliation here 1Piracicaba Dental School, State University of Campinas, Piracicaba, SP.

²School of Dentistry,Oregon Health & Science University, Oregon, USA.

Abstract

The aim of this study was to evaluate the effect of nanofiller loading on the degree of conversion (DC) and the potential color change (CC) of experimental resin-based composites (RC). Four different polymeric materials were produced using the same organic matrix 29 wt % Bis-GMA, 32.5 wt % UDMA, 32.5 wt % Bis-EMA, 6 wt % TEGDMA. To this matrix was added different loadings of 0.05 μm fumed silica filler: no filler (control), 13 wt %, 52 wt % and 65 wt %. Fourier transform infrared spectroscopy (FTIR) was used to evaluate the DC for each RC, and spectrophotometry according to CIE Lab chromatic space was used to evaluate the CC To induce color change, experimental resins were artificially aged with exposure to cycles of UV-B light for 300 h. Data were analyzed using one-way analysis of variance and Tukey’s test (α = 0.05). There was an excellent inverse linear correlation between filler wt % and DC and direct linear correlation between filler wt % and CC. Red-yellowing and opaquing effects were observed for all groups. Clinically significant color change (ΔE > 3.3) was observed after aging when the filler loading was greater than 52 wt %. A higher percentage of filler particles in dental resin composites directly affect the DC and the CC of the resins. Keywords

Silica, inorganic matrix, color stability, degree of conversion.

Funding

CAPES

111

Effect of different surface treatment techniques on repair strength of an indirect composite: an in vitro study Mesko ME*1, Loomans BAC2, Ruben J2, Huysmans MCDNJM2

1School of Dentistry, Federal University of Pelotas, RS. 2Dental school, Radaboud University Nijmegen Medical Centre, The Netherlands.

Abstract

This study investigated surface treatments (ST), silane (SI) use on immediate (noTC) or thermocycled (TC) shear bond strengths (SBS) of a direct composite bonded on LAVA Ultimate (LU). LU was cut in blocks, grinded with a 150-grit paper and assigned to different surface treatments: (1) CoJet, (2) Siljet, (3) Siljet Plus, (4) Al2O3, (5) Hydrofluoric acid 9.6% or (6) negative control (NC). In 48 samples SI was applied before the bond and in the other 48 (no SI), only the bond was applied and polymerized for 10s. Filtek Supreme XTE (FS), were applied (2 layers/2mm) with a mould and cured for 60s and each block was cut in four, resulting in 384 specimens. Half of them were subjected to 10.000 TC. All specimens were subjected to SBS. The results (mean and standard error) for the noTC groups, in Mpa, were: (1) no SI: 21.25 ± 1.38; SI: 27.72 ± 1.82; (2) no SI: 24.43 ± 1.87; SI: 26.34 ± 1.86; (3) no SI: 23.76 ± 1.63; SI: 30.85 ± 1.72; (4) no SI: 25.28 ± 1.59; SI: 24.63 ± 1.73; (5) no SI: 24.68 ± 1.22; SI: 23.88 ± 1.55; (6) no SI: 16.28 ± 1.56; SI: 21.05 ± 1.24. For the TC groups were: (1) no SI: 11.69 ± 1.52; SI: 15.41 ± 1.02; (2) no SI: 15.64 ± 1.63; SI: 15.05 ± 1.02; (3) no SI: 11.13 ± 1.31; SI: 20.92 ± 1.09; (4) no SI: 13.49 ± 1.92; SI: 13.55 ± 1.63; (5) no SI: 11.31 ± 1.79; SI: 10.50 ± 1.23; (6) no SI: 10.18 ± 1.00; SI: 11.46 ± 1.35. Data analysis showed that all ST noTC differ from NC. For TC groups only ST 2 and 3 and the use of SI as well, were significantly different from NC. It can be concluded that the surface treatments 2 and 3 and application of SI can significantly increase the SBS of fresh composite bonded on LU.

Keywords

Adhesives; Composite Resins

Funding

CAPES-NUFFIC.

112

Tensions generated in the peri-implant region between experimental model with strain gages and finite element analysis

Chase-Diaz M*1, Paschoeto GG2, Capello Sousa EA², Rubo JH3, Albarracín ML3, Borges AFS1.

1Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry - University of Sao Paulo, Bauru, SP, Brazil 2Department of Mechanical Engineering, Bauru School of Engineering, Sao Paulo State University “Júlio de Mesquita Filho”, Bauru, SP, Brazil 3Department of Prosthesis, Bauru School of Dentistry - University of Sao Paulo, Bauru, SP, Brazil

Abstract

The aim of this study was to analyze the tension distribution and deformation of the implant/prosthesis

assembly, on the peri-implant bone region comparing an experimental in vitro model with the model of Finite

Element (FE). Experimental in vitro model consisting of: Brånemark System MkIII Groovde implant (3.75 mm

diameter, 13.0 mm length); multi-unit set abutment of 5mm height with titanium screw and torque of 20Nm;

cobalt-chromium coping coated with feldspathic ceramic screwed with a torque of 10Nm, and polyurethane

simulating the bone. In this assembly were performed readings of deformations generated in the abutment and

polyurethane using strain gages coupled at three points of the abutment and in the regions mesial, buccal, distal

and lingual of the simulated bone around the implant. This assembly was scanned with micro CT and the images

obtained were used for making three-dimensional mathematical models for analysis by EF. In EF, axial load of

300N on the occlusal surfaces of the crown was applied and then the tensions were verified in the peri-implant

bone region. The values obtained from in vitro model and the FE model showed agreement among themselves.

The EF method proved to be effective for checking the tensions in the region analyzed.

Keywords

Dental Prostheses, Dental Implants, Finite Element Analysis

Funding

113

Surface roughness of orthodontic polycrystalline ceramic brackets.

Kröning MA, da Silva AV, Costa CT, Michelon D, Piva E, e Silva RM.

1School of Dentistry, Federal University of Pelotas, RS

Abstract

The physical characteristics of polycrystalline ceramic brackets can vary, so the aim of this study was to conduct a qualitative and quantitative analysis of the brackets manufacturers: Dentaurum (DENT), Morelli (MOR), 3M (3M), RMO (RMO) and TP (TP). An operator carried out the study 5 groups of 14 units each brand, 4 units of each group SEM analysis was conducted, the remaining 10 units was recorded average roughness (Ra). An element of each brand was fractured to evaluate the internal structure.

We used analysis of variance according to a route and Tukey's test (α = 5 %). Data were previously transformed using logarithmic function. The manufacturer factor (p <0.001) was shown to be statistically significant. The brackets brand 3M showed the lowest Ra values (0.52 ± 0.16- mean and standard deviation respectively), while the largest roughness was found in brackets RMO (1:01 ± 0:23, p < 0.05) scores, which in turn proved to be similar brands MOR (0.87 ± 0:23) DENT (0.76 ± 0:25) and TP (0.76 ± 0:15).

The brackets present differences in crystal structure and could be identified on surfaces irregularities, depressions, scratches and cracks, which can lead to potential structural failure.

We conclude that different brands brackets tested have different roughness and different topographical features which in turn may be reflected in the biofilm accumulation, frictional force and bond strength.

Keywords

Orthodontics, Orthodontic Brackets, Surface Properties.

114

Surface roughness of orthodontic polycrystalline ceramic brackets.

Kröning MA, da Silva AV, Costa CT, Michelon D, Piva E, e Silva RM.

1School of Dentistry, Federal University of Pelotas, RS

Abstract

The physical characteristics of polycrystalline ceramic brackets can vary, so the aim of this study was to conduct a qualitative and quantitative analysis of the brackets manufacturers: Dentaurum (DENT), Morelli (MOR), 3M (3M), RMO (RMO) and TP (TP). An operator carried out the study 5 groups of 14 units each brand, 4 units of each group SEM analysis was conducted, the remaining 10 units was recorded average roughness (Ra). An element of each brand was fractured to evaluate the internal structure.

We used analysis of variance according to a route and Tukey's test (α = 5 %). Data were previously transformed using logarithmic function. The manufacturer factor (p <0.001) was shown to be statistically significant. The brackets brand 3M showed the lowest Ra values (0.52 ± 0.16- mean and standard deviation respectively), while the largest roughness was found in brackets RMO (1:01 ± 0:23, p < 0.05) scores, which in turn proved to be similar brands MOR (0.87 ± 0:23) DENT (0.76 ± 0:25) and TP (0.76 ± 0:15).

The brackets present differences in crystal structure and could be identified on surfaces irregularities, depressions, scratches and cracks, which can lead to potential structural failure.

We conclude that different brands brackets tested have different roughness and different topographical features which in turn may be reflected in the biofilm accumulation, frictional force and bond strength.

Keywords

Orthodontics, Orthodontic Brackets, Surface Properties.

115

Evaluation of friction resistance of different orthodontic elastomeric ligature

Lopes MB1* Miasaki A1, Hirata BS1, Berger SB1, Guiraldo RD1, Gonini-Júnior A1

Inserir aqui filiação 1Departament of Restorative Dentistry, School of Dentistry, University of North Parana, PR.

Abstract

In conventional orthodontics devices the fixation of the arch with the bracket occur thru elastomeric ligatures. Due to the marketing appeal, these ligatures could be found in varied colors, which occur with incorporation of different stains. Then, this work compared thru friction test. 7 different colours and 2 brands of ligature were used. Standard Edgwise Agile slot 0.022in incisive brackets, three types of orthodontic alloy (Niti, TMA and steel 0,019X0.025-pol) were used. For each combination support-arch, 10 observations were made using an apparatus composed of a base, where the brackets were fixed and a acrylic cylinder positioned in a universal testing machine. The test were realized at 5mm/min with 10mm of displacement at 0 degrees. The means (in N) were submitted to Anova and Tukey’s test (α=0,05). The steel wire (0.67±0.36) showed statistical less friction than TMA (1.84±0.81) and Niti (1.53N±0.96). GAC (1.13±0.76) had statistically less friction than Morelli (1.56N±0.97). The colors purple (1,36N±0.72)., orange (1.12N±0.86), light rose (1.05N±0.65) and dark rose (0.84N±0.53) statisticaly had less friction compared to the other colors. The pigmentation of the ligatures influenced the friction with the orthodontic wire.

Descritores

Orthodontic, ligature, friction

Apoio

Funadesp

116

Influence of the cement film thickness on the push out bond strength of fiber posts cemented in human root canals Prado NAS*1, Ferreira R de S1, Gonzalez MR1, Maurício MH de P2, Paciornik S2, Miranda MS de1.

1School of Dentistry, State University of Rio de Janeiro, RJ 2Department of Materials Engineering, Pontifical Catholic University of Rio de Janeiro, RJ

Abstract

The aim of this study was to evaluate the influence of the cement film thickness on the push out bond strength of glass fiber posts in the cervical, medium and apical thirds of root canal spaces, cemented with self-adhesive resin cement. Thirty endodontically treated roots were randomly divided into three groups, according to the WhitePost DC (FGM) system’s drills: (G1) #2; (G2) #3; (G3) #4. The posts were cemented using RelyX U100 (3M ESPE), and a small amount of powdered Rhodamine B was used as a stain. The roots were sectioned and submitted to push out test. Images of both sides of each slice were obtained using a stereomicroscope before and after the test. To determine the cement thickness, a macro routine was developed using the software, KS 400. The data were analyzed statistically using Two-way ANOVA, Kruskal-Wallis test and Duncan test. The results showed that G3 (248.78µm) presented statistically higher values of cement film thickness, followed by G2 (185.91µm) and G1 (110.16µm). G2 (14.62 ± 5.15MPa) showed statistically higher bond strength values than G1 (10.04 ± 5.13MPa) and G3 (7.68 ± 6.14MPa). All groups presented higher bond strength values in the apical third. The slight increase in the cement thickness allowed an increase in the bond strength values when compared with very thin or very thick cement films.

Keywords

Dental dowels. Fluorescent dyes. Resin cements. Root canal preparation. Shear strength.

117

Composite based epoxy and polyurethane for the development of dental models Marins NH1*, Silva RM1, Ogliari AO2, Ramos TS2, Ogliari FA1

1 School of Materials Engineering, Federal University of Pelotas, Pelotas, RS

2 School of Dentistry, Federal University of Pelotas, RS

Abstract

The study evaluated a new alternative for making dental models, by using a composite of epoxy resin (ER) and other based in polyurethane (PU). Different composites were prepared using ER and added 0% (control), 10%, 20% and 30% in mass of quartz #100 and the same with the matrix of PU. Material properties were evaluated according to ISO 14233-2003, the tests made Knoop hardness (KH), flexural strength (RF), modulus of elasticity (E), dimensional stability (DS) and scanning electron microscopy (SEM). The data was analysed using two-way ANOVA (p <0.05) and qualitative analysis.The results showed that the samples of RE had higher hardness when compared to PU, the ER group having 20% filler was the best for KH. The groups based ER also obtained better RF performance when compared to PU, with the highest valuesERcontrol (82.78 ± 2.25 N), ER10% (114.93 ± 0.96 N) and PUcontrole lowest (7.84 ± 0.3 N) and PU10% (23.30 ± 0.5 N). In the RE groups, the modulus of elasticity was increased as decreasing the concentration of charge, as for the PU the effect was reversed. The groups ER30%, PUcontrole, PU10% and PU20% showed lower expansion than 1%. SEM was observed different patterns of distribution of the particles. The addition of 30% of quartz particles in the matrix-based epoxy resin provides improved properties to the material.

Keywords

Microscopy, Dental Models

118

Post-etching ultrasonic bath: influence on ceramic flexural strength and precipitates removal Rossi NR*1, Cotes C1, Macedo, VC1, Kimpara ET1

1 Department of Dental Materials and Prosthodontics, Institute of Science and Technology, UNESP

Abstract

The aim of this study was to evaluate the effectiveness of the ultrasonic bath to remove precipitates formed after etching and its influence on the flexural strength of lithium disilicate ceramics. 40 ceramic bars were fabricated and divided into 4 groups ( n=40): A, no treatment (control ) ; HF , application of 5% hydrofluoric acid (HF) for 20s, washing (40s), drying (30s); HFC , HF (20s ), washing (40s) , drying (30s), silanization and luting agent; HFU , HF (20s), washing (40s), ultrasonic bath in distilled water for 4 min, drying (30s), silanization and luting agent. After 24 hours, the bars were subjected to three-point bending test. Representative images of the treatments (no treatment, application of acid and washing, and application of acid, washing and ultrasonic bath) were analyzed by Scanning Electron Microscope . There was no significant difference between the means of the groups according to ANOVA one-way (p-value=0.150). In Scanning Electron Microscope images, it were observed formation of precipitates that were removed after ultrasonic bath. It was concluded that the ultrasonic bath removed the precipitates formed after etching, but it’s not result in mechanical strength increase of lithium disilicate ceramic.

Keywords

Ceramics, Hydrofluoric Acid

Funding

FAPESP ( 2011/11301-6 and 2012/16009-4)

119

Optical behavior of dental zirconias and human dentin through the kubelka-munk theory Pecho OE*1,2, Ghinea R2, Ionescu AM

2, Cardona JC2, Della Bona A1, Pérez MM 2.

1Post-graduate Program in Dentistry, Dental School, University of Passo Fundo, Brazil 2Department of Optics, Faculty of Science, University of Granada, Granada, Spain

opey@correo.ugr.es

Abstract

The aim of this study was to use the Kubelka-Munk theory to evaluate the scattering (S), absorption (K) and transmittance (T) of non-colored and colored dental zirconia systems and human dentin (HD). Two zirconia systems were used: ZC- ZirCAD (Ivoclar Vivadent) and LV-LAVA (3M ESPE). Specimens from each ceramic system were divided into 2 groups (n=5): ZC1 and LV1 (non-colored), and ZC2 and LV2, which were colored with coloring liquid CL2 and FS3 corresponding to shades A3/A3.5 and A2/A3, respectively. Five human anterior teeth were flattened and polished through 1200 grit SiC paper to expose the superficial dentin. All samples were prepared to a final thickness of 0.5 mm. Diffuse reflectance was measured against white and black backgrounds, using a spectroradiometer (PR 704, Color Research, USA) in a viewing booth (CAC D60, VeriVide, UK) with D65 illuminant and d/0˚ geometry. S and K coefficients and T were calculated using Kubelka-Munk’s equations. Data was statistically analyzed using Kruskal-Wallis, Mann-Whitney tests, and VAF coefficient. Spectral distributions of S, K and T were wavelength dependent. The spectral behavior of S and T was similar to HD (VAF 96.80), even though they were statistically different (p≤0.05). The spectral behavior of K was also similar to HD, except for LV1 (VAF=38.62), yet all ceramics were statistically different from HD (p≤0.05). Zirconia ceramics showed S values greater than HD, but K and T values lower than HD.

Keywords

Scattering, absorption, zirconia

120

Evaluation of different surface treatments on fiberglass posts on the bond strength to composite resin Nizo PT*1, Vitti RP1, Spazzin AO2,3, Farina AP2, Cecchin D2, Bacchi A1,2, Sinhoreti MAC1, Moraes RR3.

1Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas, Piracicaba, SP. 2Department of Prosthodontics, Meridional Center of Dental Studies, Meridional Faculty, Passo Fundo, RS. 3Department of Operative Dentistry, School of Dentistry, Federal University of Pelotas, Pelotas, RS.

Abstract

The objective of this study was to evaluate the effect of differents glass-fiber post (GFP) surface treatments on microtensile bond strength (BS) to a composite resin. The GFPs were divided into two groups: etched or not with phosphoric acid 37% (Condac 37, FGM). These groups (n = 5) recevied more three different surface treatments: silane coupling agent (Silano, Angelus), unfilled resin (Adper Scotchbond Multi-Purpose, 3M ESPE) or silane + adhesive. All materials were used according to the manufacturer's instructions. Composite resin blocks (Z250 XT, 3M ESPE) were built on GFP surface. The BS was performed using an universal testing machine (Instron). The results were submitted to two-way ANOVA and Student-Newman-Keuls’ (5%). The modes of failure were classified as adhesive, mixed or cohesive failures. Additional specimens (n = 3) were performed to analysis of the bonded interfaces by scanning electron microscopy (JEOL JSM-5600LV). The control group (no treatment) showed the lowest values of BS, irrespective the acid etching. The highest values of BS were found to silane + adhesive group, irrespective the acid etching. The non-etched group had a predominance of adhesive failures. In other hand, the etched group had more number of cohesive failures. Differences regarding the homogeneity and thickness of the adhesive layer formed by different GFP surface treatments were observed. The application of silane with unfilled resin can improve the BS between GFPs and resin composite.

Keywords

Dental Materials, Permanent Dental Restoration, Dental Acid Etching

Funding

CNPq

121

Phase transformations on ZTA and Y-TZP ceramics after ageing

Cesar PF*1, K. Monteiro KN1, Fukushima K1, H. Yoshimura H2, Souza G3.

1Universidade de São Paulo. 2Universidade Federal do ABC, University of Toronto

Abstract

This work evaluated the effect of ageing on crystalline phase content of Y-TZP-based ceramics. Flexural strength/FS

and Vickers hardness/VH of materials were also evaluated. CAD-CAM blocks were produced from: commercial Y-

TZP (YZ-com/In-Ceram YZ/Vita), experimental Y-TZP (YZ-exp), and experimental zirconia-toughened-alumina (ZTA).

Slices of 14x15x2mm were obtained by cutting pre-sintered blocks with a diamond blade and final sintering was

carried out at 1530°C/3hours for YZ-com and YZ-exp and at 1650°C/3hours for ZTA. Properties determined were:

VH (2kg/20s) and FS (biaxial). X-ray diffraction was employed to quantify the crystalline phases on materials before

and after ageing. One-way ANOVA was used for VH and FS and Student’s t-test to verify the ageing effect. YZ-com

showed significantly higher FS, in MPa, (841,0±159,7) compared to YZ-exp (695,6±115,7), which was significantly

higher when compared to ZTA (460,9±130,1). YZ-com and YZ-exp showed similar VH values, in GPa, (12,4±0,8 e

11,6±0,6, respectively) that were significantly lower than that of ZTA (14,1±1,4). Cubic phase content was not

affected by ageing for any of the ceramics evaluated. Tetragonal phase content decreased and monoclinic phase

content increased significantly after ageing for YZ-com and YZ-exp. Although ZTA showed lower strength and

hardness compared to Y-TZP, it had higher resistance to low temperature degradation due to low interconnectivity

of ZrO2 particles and the constraint caused by the Al2O3 matrix.

Keywords

Zirconia, hardness, strength

Funding

FAPESP

122

Different surface treatments of bond strength of zirconia

Oliveira, PCG*; Almeida, ALPF; Neppelenbroek, KH, Bonfante, EA; Santos, LA.

Insert affiliation here

Department of Prosthodontics, School of Dentistry, São Paulo University.

Abstract

High crystalline content ceramics, such as Yttria stabilized tatragonal zirconia polycrystal (Y-TPZ) show great properties when compared to conventional ceramics. However, its success also depends on the reliable bond formation with luting agents. Therefore the purpose of this study was to evaluate the effect of the bond strength after different surface treatments on the zirconia using one resin cement (Rely X U100). Forty rectangular samples of zirconia were embedded in acrylic resin and divided into 4 groups (n=10). G1 (no treatment); G2 (Alloy Primer); G3 (Metal/zirconia Primer) and G4 (air abrasion with 50 µm aluminium particles). The specimens were stored in distilled water at 37ºC for 24 hours prior the shear bond strength test in a mechanical testing machine (EMIC). The data were analyzed by ANOVA and Tukey test. The results (MPa) presented were: G1 – 11.71; G2 – 21.49; G3 – 30.38 and G4 – 34.40. In conclusion all treatments increased the Bond strength of zircônia and the best results were with the sandblasting followed by the metal alloy primer and alloy primer.

Keywords

Ceramics zirconia shear bond strength

Funding

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).

123

Evaluation of the effect of medication containing doxycycline associated with alendronate on bone healing in rat femur defects.

Insert affiliation here

Department of Cell Biology, Histology and Embryology, School of Dentistry, Federal University of Uberlândia, MG

Abstract

Doxycycline and alendronate are drugs that can inhibit bone resorption, promoting osteogenesis. The purpose of this study was to analyze the effect of 10% doxycycline gel with 1% alendronate on bone healing in rat femurs. Thirty animals were divided into 3 groups: control group ( GI ) Drugs Group ( GII ) and Vehicle Group ( GIII ) . In all groups, the bone defect was created in the right femur. In GI, the defect was filled only with blood clot. In GII the defect was filled with 1 ml of 10% doxycycline gel with 1% alendronate, in GIII filled only with the drug vehicle. The animals were sacrificed after 7 and 15 days. Bone density and the percentage of bone matrix were quantified and analyzed statistically (p < 0.05). Within 7 days, GII (177.80 ± 76.52) and GIII (147.10 ± 41.59) groups had higher bone density than GI (80.38 ± 27.41). However, during this same period, the GI (0.25 ± 0.04) and GIII (0.26 ± 0.04) showed a higher percentage of bone matrix relative to GII (0.18 ± 0.07). At 15 days, both the bone density and the percentage of bone matrix were higher in GII (405.20 ± 63.16, 0.31 ± 0.04, respectively). 10% doxycycline gel with 1% alendronate favored bone formation within 15 days.

Keywords

Doxycycline, Alendronate, Osteogenesis

Funding

FAPEMIG, CNPq.

124

Evaluation of stress distribution pattern on walls of non-carious cervical lesions in different morphologies Spini PHR*, Zeola LF, Machado AC, Soares PV .

Insert affiliation here 1School of Dentistry, Federal University of Uberlândia, MG

Abstract

This study aimed assess the influence of non-carious cervical lesions (NCCLs) morphologies and type of loading on stress distribution by 3D finite element analyses. 21 premolars models were generated, varying the NCCLs morphology: Sound (SO), wedge-shaped (WS), rounded (RO) and mixed (MI), in addition the respective models restored with composite resin (R) were created. The models were considered linear and elastic. Three types of occlusal load (100N) were applied: axial (AL), palatine (PL) and buccal (BL). Through the software tool Ansys Workbench, the values of tensions were collected by the criterion of maximum principal stress, on all of the elements of the walls: occlusal (OW), gingival (GW), traversal bottom of NCCLs (TW) and the longitudinal bottom of the lesion (BW); allowing quantitative analysis. For AL, there was lower tensile stress concentration for all walls, regardless of the morphologies or the presence of restoration. PL presented greater accumulation of tensile on TW, mainly in the WS morphologies (28, 23MPa) and MI (33, 02MPa). BL presented in compression on TW and tensile stress on OW. For all morphologies, regardless of the type of loading, PO and FT are the walls which presented greater mechanical and request tensile stress, near of 41MPa. However, for the restored models were found smaller traction stress values. The breakdown stress in different morphologies is influenced by the type and morphology of NCCLS. The restorative procedure retrieves the biomechanical behavior of the sound model.

Keywords

Tooth wear, Dental Occlusion, Premolar Tooth

Funding

Fapemig

125

Effect of sodium p-toluenesulfinate (p-TSNA) in the kinetics and degree of conversion of experimental self-adhesive resin cements 2Albuquerque PPAC*, 3Schneider LFS, 1Moraes RR, 2Cesar PF, 2Rodrigues-Filho LE

Insert affiliation here 1School of Dentistry, Federal University of Pelotas, RS 2School of dentistry, University of São Paulo, SP 3School of Dentistry, Federal Fluminense University, RJ

Abstract

Evaluate the kinetics of polymerization (KP) and the degree of conversion (DC) of experimental self-adhesive resin cements (SARCs), due to the addition of p-TSNA. Four types of cement paste-paste were formulated with UDMA, HEMA BISGMA, TEGDMA and acid monomers (AM) 2MP HEMA-P, 4-MET, GDMA-P as organic matrix. Camphorquinone/EDMAB and Benzoyl Peroxide/DHPT were employed as dual activation system. The cements were tested with and without the addition of p-TSNA. Filler particles were incorporated at a ratio of ± 55% in final weight. The technique of infrared spectroscopy (FT-IR) was used for analysis of KP in real time (10 min) and DC after 24 h, from the chemical and dual cure. When necessary, a LED source was used during 40s with irradiance of 1.200 mW/cm2. The results were submitted to ANOVA three way and Tukey test (alpha = 5%). All factors and their interactions (AM, activation type and presence or absence of p-TSNA) were statistically significant (p <0.05). The addition of the p-TSNA reduced chemical polymerization for 5 min. All groups showed a high DC (> 85%) after 24 h regardless of the presence of p-TSNA, except the group with GDMA-P, which showed a significant increase in the DC after adding this component (chemical 9%→90%; dual 57%→89%). The monomer HEMA-P showed a very fast polymerization reaction (<30 s) invalidating the tests. Therefore, the addition of p-TSNA besides favoring a high DC, allowed a greater control of chemical polymerization.

Keywords

Resin Cements, Dental Materials, Dental Bonding

126

Effect of a new bioactive glass on the titanium implants osseointegration: experimental study in dogs Soares PBF*1, Moura CCG2, Chinaglia CR3, Zanotto ED3, Stavropoulos A4, Zanetta-Barbosa D1

1Department of Oral and Maxillofacial Surgery and Implantology, School of Dentistry, Federal University of Uberlândia, MG 2Department of Biological and Natural Sciences, Federal University of Triângulo Mineiro, MG 3Department of Materials Engineering, Vitreous Materials Laboratory, Federal University of São Carlos, SP 4Department of Periodontology, Faculty of Odontology, Malmö University, Malmö, Sweden

Abstract

This study evaluated the stability and osseointegration of implant with bioactive treatment in terms of resonance frequency analysis (RFA) and histomorphometric analysis. Forty Morse taper implants (length 7 mm, ø3.5 mm) with sandblasted and dual acid-etched surface treatment were used. Half of the implant (n=10) received additional treatment using bioactive glass (BG, experimental) and the other half (n=10) was used as a control (E). Ten Beagle dogs had the mandibular premolars extracted, after 8 weeks were installed 2 implants in each side in two periods (right side –2 weeks, left side – 4 weeks). The RFA (Ostell®) was obtained immediately and after the sacrifice. The bone/implant blocks were processed for histomorphometric analysis (bone implant contact, BIC; and bone density between around implant, BD). Data were analyzed using two-way ANOVA followed by Tukey test (P=0,05). For RFA only the implant type had significant influence (P=0.039). Only time had significant influence on BIC values (P=0.020). For BD values the time/implant interaction had significant influence (P=0.046). RFA for BG was significantly higher than E group, irrespective of time. The BIC values at 4 weeks were significantly higher than at 2 weeks, irrespective of implant. The BD values of E group for 4 weeks were significantly higher than for 2 weeks, but BG was not influenced by the time. Surface treatment using bioactive glass is important to improve early interaction between bone/implant.

Keywords

Bioactive glass, titanium implants, histomorphometry

Funding

FAPEMIG and NEODENT

127

Effect of photoactivation protocols on bonding brackets to enamel Mirapalhete RC*, Oliveira AS, Amaral CC, Moraes RR.

School of Dentistry, Federal University of Pelotas, RS

Abstract

This study investigated the effect of photoactivation protocols on the shear bond strength (SBS) of brackets to enamel. Metal brackets were bonded to bovine incisors using Transbond XT (3M Unitek). Four photoactivation protocols of the bonding cement were tested (n=15): Control (C) – photoactivation for 10s on each lateral side of the bracket at a time; Simultaneous (S) – photoactivation for 10s on both lateral sides of the bracket at the same time; One side-20s (O20) – photoactivation for 20s at one lateral side of the bracket only; and One side-10s (O10) – photoactivation for 10s only at one lateral side of the bracket only. SBS was tested immediately or after 1000 thermal cycles. Adhesive remnant index (ARI) was classified. Data were subjected to 2-way ANOVA and Student-Newman-Keuls’ test (5%). The Pooled means ±standard deviations for SBS (MPa) were 10.2±4.2 (C)a, 9.7±4.5 (S)a, 5.6±3.1 (O20)b, and 4.6±1.9 (O10)b. Pooled results for immediate and thermal cycled groups were 6.3±2.6b and 8.8±5.2a. A predominance of ARI scores 1-2 and 0-1 was observed for the immediate and thermal cycled groups, respectively. In conclusion, simultaneous photoactivation had the same bonding ability compared to the conventional light-curing method of orthodontic cements. Photoactivation at one side only is not recommended.

Keywords

Bonding, light-curing, orthodontics

128

Development of experimental endodontic sealers based on MTA and salicylate Vitti RP*1, Sinhoreti MAC1, Zanchi CH2,Ogliari FA3, Piva E2.

1Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas, Piracicaba, SP. 2Department of Operative Dentistry, School of Dentistry, Federal University of Pelotas, Pelotas, RS. 3Technology Development Center, School of Materials Engineering, Federal University of Pelotas, Pelotas, RS.

Abstract

The objective of this study were to develop and evaluate physico-mechanical properties of three experimental root canal sealers based on mineral trioxide aggregate (MTA) and resin salicylate. The materials were composed by one base paste and three differents catalyst pastes. The base paste was prepared with bismuth oxide and 1,3-butyleneglycol disalicylate. Three different catalyst pastes were formulated: (G1) Resimpol 8 (RP8) + titanium dioxide (TiO2) + MTA, (G2) RP8 + TiO2 + MTA + hydroxyapatite and (G3) RP8 + TiO2 + MTA + dibasic calcium phosphate dehydrate and titanium dioxide. MTA Fillapex (Angelus) was used as control. Some physico-mechanical properties were analyzed such as: flow and working time (ISO 6876:2001), viscosity and setting time (Brookfield viscometer spindle, SC4-18 model) and diametral tensile strength (Instron 1144), in accordance with the specifications. Data were submitted to one-way ANOVA and means compared by Tukey test (5%). MTA Fillapex showed the highest values for all properties. Regarding the experimental materials, G2 and G3 showed the highest values of working and setting times. Higher flow was found to G3. For viscosity and diametral tensile strength all experimental sealers were statistically similar. The properties analyzed in the experimental materials showed values close to those recommended by the specifications in order to sealers be used clinically.

Keywords

Dental Materials, Viscosity, Calcium Phosphates

Funding

FAPESP

129

Effect of activation method on immediate biaxial flexural strength of dual-cure resin cements

Lima RBW*1, Sartori CG1, Goes MF1.

1School of Dentistry, University of Campinas, Piracicaba, SP

The aim of this study was to evaluate the immediate biaxial flexural strength (BFS) of dual-cure resin cements, submitted to different activation methods. Two resin cements were used: RelyX U 200 automix (self-adhesive) and Variolink II (conventional). The cements were applied in Teflon molds (0,5 mm thickness x 6,5 mm diameter) placed on a controlled temperature surface (35ºC). Forty specimens were made for each material. The specimens were polymerized using the following methods: self-curing mode, direct light-curing and indirect light curing mode (using a 6 mm distance and a 6mm composite resin barrier). Cements were submitted to exposure to visible light for 40s (28 J/cm2). The BFS test was performed using a universal testing machine working at 1.27mm/min speed, 15 min after specimen preparation. The values of BFS were submitted to two-way variance analysis (p<0.05). The direct light-curing mode presented significantly higher values compared within direct light-curing method, regardless the material employed (p=0.00001). The conventional resin cement (133.7MPa) presented significantly higher values compared to self-adhesive cement (119.1 MPa), regardless the light-curing mode employed (p=0.00005). The self-cured mode specimens did not achieve enough chemical polymerization to be submitted to BFS test after 15 minutes. Light curing was essential to obtaining immediate BFS values for the resin cements tested. Indirect curing mode method produced lower BFS for both resin cements.

Keywords

resin cements, light-curing of dental cements, dual-curing of dental cements

130

Stability of masking ability and opacity of ceramic systems with different resin cements Rodrigues RB*1, Lopes CCA1, Roscoe MG2, Lima E2, César PF2, Simamoto-Júnior PC1, Soares CJ1, Novais VR1

1 School of Dentistry, Federal University of Uberlandia, MG 2 School of Dentistry, University of Sao Paulo, Sao Paulo, SP

Abstract

Aimed to evaluate color stability through the masking capabilities (CM) and opacity (OP), of ceramic systems cemented with different resin cements, by calculating the color difference (ΔE) in measuring the coordinates L * a * b * reflectance. Two ceramic (feldspathic and enhanced by Lithium disilicate) and 2 resin cements - color A3 (RelyX ARC and Variolink II) formed 4 experimental groups (n=5). 10 disks were fabricated for each ceramic (10 X 1.5 mm), etched with hydrofluoric acid 10%, and silanized prior to cementation. The color analysis was done 24 hours after cementation and after 6 months storage by spectrophotometry in black and white background. One-Way ANOVA showed no statistical difference between the groups in any of the times evaluated, initial CM (p=0.243) and after 6 months (p=0.427); Initial OP (p=0.527) and at 6 months (p=0.354). Paired t test comparing values before and after storage showed no significance for CM (p=0.434) nor for OP (p=0.489). Pearson correlation between CM and OP showed coefficient C=-0.965, indicating high correlation between CM and OP inversely significant (p<0.050). It was concluded that the ceramic together with resin cements behaved similarly and did not affect CM and OP. Neither group was able to mask the black background, as ΔE values were above the clinically acceptable limit (ΔE<5). The measured optical properties were not affected by storage. There is a strong correlation between CM and OP.

Keywords

Ceramic, Color, Cementation

Funding

FAPEMIG

131

Radiopacity of root canal filling materials used in primary teeth

Casarin RP*1, Pilownic KJ1, Almeida LHS1, Romano AR1, Pappen FG1.

1School of Dentistry, Federal University of Pelotas, Brazil .

Abstract

Radiopacity is one of required properties of root canal filling materials for primary teeth. The aim of this study was to evaluate the radiopacity of different endodontic materials used in primary teeth. The following materials were included in the study: conventional Guedes-Pinto paste; modified Guedes-Pinto paste, replacing Rifocort by Omcilom Orabase; calcium hydroxide paste associated with iodoform (Hydropast); calcium hydroxide paste (Calen) thickened with zinc oxide; and zinc oxide and eugenol cement (ZOE). Standardized Acrylic plates with 5 mm diameter and 1 mm in depth openings were used as molds for the materials. The samples were radiographed and compared with a calibrated aluminium scale, ranging from 0.5 to 5 mm. Occlusal digital sensors with focal length standardized in 30 cm, and exposure time of 0.2 s were used. The radiographic density values obtained using Adobe Photoshop 12.0.4 software were converted into mmAl. The tests were performed in triplicate, and data were analyzed statistically using the ANOVA and Tukey tests (P = 0.05) tests. Calen thickened with zinc oxide and the modified Guedes-Pinto paste were the most radiopaque materials (8.81 mmAl and 8.18 mmAl respectively), followed by conventional Guedes-Pinto paste (7.39 mmAl), ZOE (6.67 mmAl) and Hydropast (6.38 mmAl). It can be concluded that all tested materials presented more than 3 mmAl radiopacity, and all of them are in accordance with ISO determination.

Key words

Primary Teeth, Endodontics, Root Canal Therapy

132

Performance assessment of dental shade guides by dental students Alessandretti R*1, Ribeiro R2, Pecho OE1, Della Bona A1.

1 Post-graduate Program in Dentistry, Dental School, University of Passo Fundo, Brazil

2 Dental School, University of Passo Fundo, Brazil

Abstract

The goal of this study was to evaluate the influence of two shade guides on shade matching performance by dental students (DS). Fifty DS volunteers, approved by the Ishihara's Test for Colour-Blindness, completed the study. A spectrophotometer (EA- Easyshade Advance, Vita) was used to measure the color coordinates CIE L*a*b* of 5 human upper central incisors (ICS) and the shade tabs from the shade guides Vita Classical (VC) and Vita Toothguide 3D-Master (3D) over a gray background (Flexipalette Color Match) in a viewing booth (Macbeth Judge II, X-rite), under D65 illuminant and optical geometry of 0/45º. Teeth were kept moist during the experiment. The average of three measurements performed in the middle third of each tooth and shade tab was recorded. The volunteers were instructed to use the VC and 3D and selected the shade of the ICS, following the same settings used in the evaluation with EA. Color difference values (ΔE*ab) between the selection of the DS and the EA measurements were analyzed. Visual assessment (subjective) showed ≤ΔE*ab values than objective measurements (EA) in four teeth. The ICS showed different color coordinates from those found for the matched shade tab selected by DS. Mostly because the human eye considers all parameters involved in color selection and the instrument only considers the CIE L*a*b* coordinates, indicating the closest Vita shade tab. Thus, the EA should be used with caution, as an auxiliary tool for shade matching in dentistry.

Keywords

Color, color perception, tooth

Funding

FAPERGS (396-2551/14-1) e (1007-2551/13-2), CAPES do Brasil (PNPD 42009014007P4) e Pq-CNPq (304995-2013-4).

133

Evaluation of the bond durability between different resin cements and a glass ceramic

Carvalho RLA*1, Duarte MR2, Carvalho RF2, Leite FPP2, Kimpara ET1

1 Institute of science and technology of São José dos Campos – UNESP, SP 2 School of Dentistry, Federal University of Juiz de Fora, MG

Abstract

The aim of this study was to evaluate the bond durability between different resin cements and a feldspathic ceramic. Twenty feldspathic ceramic blocks (Vita Mark II) were obtained with dimensions 12x7x5mm and duplicated in composite resin (W3D Master). The groups were divided according to the cementation protocol (n=10): HSCp – 10% hidrofluoridric acid, silane, heat treatment and Panavia F and HSCr – 10% hidrofluoridric acid, silane, heat treatment and cement RelyX ARC. After the ceramic cementation on the resin blocks, the sets (ceramic resin cement resin composite) were sectioned with a precision cutting machine, resulting in 18 samples (sticks) block, measuring 8x1x1mm. Half of the samples of each group was aged by thermocycling (10,000 cycles: 5/55°C), by creating groups HSCpT and HSCrT. All specimens were submitted to the microtensile bond strength test using a universal testing machine (EMIC). The results were evaluated using two-way ANOVA. There was no interaction between resin cement and thermocycling (p=0.429). The thermocycling did not influence the bond strenght (p=0.105). The Panavia F cement, HSCp (33.46 ± 5.19 MPa) e HSCpT (29.31 ± 3.81 MPa), showed higher bond strength to the feldspathic ceramic compared to RelyX ARC cement, HSCr (23.87 ± 2.69 MPa) e HSCrT (22.39 ± 2.18 MPa). The values of bond strenght did not change significantly after aging. The Panavia F showed higher bond strength than RelyX ARC in aged and non aged conditions.

Keywords

Ceramics, Resin Cements, Silanes

Funding

134

Effect of irradiation on resin cements diametric tensile strength

TANGO RN*, SILVA MFB, RODRIGUES DMC, COSTA AKF, BORGES ALS, KAMINAGAKURA E

1School of Dentistry, Institute of Science and Techonology/ UNESP, São José dos Campos, SP

Abstract

The aim of this study was to evaluate the effect of irradiation on resin cements diametric tensile strength. Twenty disc-shaped specimens (4mm in diameter x 2mm in high) were obtained of each resin cement (conventional - Rely-X ARC and self-adhesive - Rely-X U200). Half of specimens was light-cured with a LED light-curing unit (1100mW/cm2) and the remainder was polymerized chemically (n=5). After 24h of storage in water in a light-proof container at 37°C, half of specimens was submitted to x-ray irradiation under 60Gy. After additional 24h, specimens were submitted to diametric tensile strength test in a universal testing machine, at a cross-head speed of 0.5mm/s. Control groups were tested at this time as well. Data of tensile strength (N) were submitted to 3-way ANOVA and to Tukey’s test, both with α=0.05. ANOVA showed significance of isolated factors and also in the resin cement type/ polymerization type interaction (p<0.05). Irradiated groups presented higher values of tensile strength (659N) when compared to non-irradiated groups (610N). Conventional resin cement presented higher values of tensile strength compared to self-adhesive cement and light-curing showed to be important to achieve higher tensile strength values. Irradiation with high energy can improve materials immediate tensile strength.

Keywords

Radiotherapy, Resin Cement, Tensile Strength

Funding

PROPE-UNESP

135

Hard machining, glaze firing and hydrofluoric acid etching: do these procedures affect the flexural strength of a leucite glass-ceramic?

Fraga S*1, Valandro LF2, Bottino MA3, May LG2.

1 Dental Science Post Graduate Program, School of Dentistry, Federal University of Santa Maria, RS. 2 Department of Restorative Dentistry, School of Dentistry, Federal University of Santa Maria, RS. 3 Department of Dental Materials and Prosthodontics, School of Dentistry, São Paulo State University - São José dos Campos, SP.

Abstract

This study aimed to evaluate the effect of hard machining, glaze firing and hydrofluoric acid etching on the flexural strength of a CAD/CAM leucite glass-ceramic. 144 discs were machined using Cerec MC XL (Sirona, Germany) and randomly divided into groups (n=24): 1) machining (M), 2) machining and glaze firing (MG), 3) machining and hydrofluoric acid etching (MA), 4) machining, glaze firing and hydrofluoric acid etching (MGA), 5) machining and polishing (MP), 6) machining, polishing and hydrofluoric acid etching (MPA). The roughness after each treatment was measured. The discs were submitted to a piston-on-three ball test (ISO 6872/2008) and the strength data analyzed using Weibull statistics (95% CI). When compared to MP group, machining (M) was able to introduce defects in the ceramic surface, reducing its characteristic strength (σ0) (MP: 177,2 MPa; M: 128,2 MPa). The glaze firing did not affect the roughness, but reduced σ0 (M: 128,2 MPa; MG: 109 MPa). Hydrofluoric acid etching increased the roughness without affecting σ0. Therefore, procedures performed prior to the cementation of leucite glass-ceramic CAD/CAM restorations have different impacts on the material strength, since hard machining and glaze firing are able to reduce glass-ceramic strength, while hydrofluoric acid etching seems not affect the material strength.

Keywords

CAD-CAM, Glass ceramics, Material resistance

Funding

This investigation was supported in part by FIPE ARD 2012 from Federal University of Santa Maria and by FAPERGS/CAPES 009:2011. These authors would like to thank Ivoclar Vivadent for their donation of the ceramic blocks used in the pilot study.

136

Techniques for restoring enlarged canals: an evaluation of fracture resistance and bond strength Aquino SA*, Poskus LT, Pereira KF, Latempa AM.

Insert affiliation here

School of Dentistry, Fluminense Federal University, Niterói - RJ

Abstract

This study evaluated the influence of fibreglass post diameter, as well as use of accessory posts on fracture resistance and bond strength, when used forrestoring enlarged root canals. One hundred maxillary single-rooted canine human teeth were decoronated and root canals were prepared using a nº4 drill (White Post, FGM, Joinville, SC, Brazil). The roots were assigned to five groups: (EC1) post nº1 (Exacto Cônico, Angellus, Londrina, PR, Brazil); (EC2) post nº2 (Exacto Cônico, Angellus); (EC3) post nº3 (Exacto Cônico, Angellus); (ECA) post nº1 (Exacto Cônico, Angellus) plus two accessory posts (Reforpin, Angellus); (WP) post nº4 (White Post, FGM). Posts 1 to 4 have a crescent diameter. Posts were luted (Rely X-Arc, 3M ESPE, USA) and composite resin filling cores were prepared for the fracture resistance test (n=10). For the push-out test (n=10), roots were sectioned into 1mm thick slices. Both tests were performed in a universal testing machine. Data were analyzed using ANOVA and Tukey's test. The results show Groups WP and EC3 had higher fracture resistance than the other groups (p <0.05), which were statistically similar. Root fractures occurred in 14% of the specimens. Groups EC1 and EC2 had lower bond strength values than Groups EC3 and ECA which were lower than the WP Group (p<0.05). Bond strength was lower in the apical and middle third than in the cervical third of root canals (p<0.05). Thicker posts were associated with higher resistance to fracture and bond strength to root canals. Using a post plus two accessory posts improved the bond strength but not the fracture resistance.

Keywords

Tooth Root

Dental Restoration, Permanent

Post and Core Technique

Funding

137

Penetration and citotoxicity of a bleaching gel activated by led/laser in restored teeth

Parreiras SO*1, Serrano AM2, Moreira CG3, Cartagena AF4, Otuki M5, Loguercio AD6, Reis A7.

1 Department of Restorative Dentistry, State University of Ponta Grossa, PR.

2 School of Dentistry, University of the Americas, Quito, Pichincha, EC.

3 Department of Pharmacology, Federal University of Paraná, PR.

4 Department of Restorative Dentistry, State University of Ponta Grossa, PR.

5 Department of Pharmacology, Federal University of Paraná, PR.

6,7 Department of Restorative Dentistry, State University of Ponta Grossa, PR.

Abstract

This study evaluated the amount of hydrogen peroxide (HP) in the pulp chamber of teeth with composite resin and its cytotoxic effect on fibroblast cell line 3T3/NIH. One hundred and twelve human premolars were randomized into 7 groups according to the combination of factors: Restoration (no restoration [NR]; shallow [S]; deep [D]) and Activation by Light (yes [A] or not [NA]). With exception of the groups control and NR, class V cavities (3 mm x 2 mm x 1 mm [S] and 3 mm x 2 mm x 2 mm [D]) were prepared and restored with composite resin. An acetate buffer was placed in the pulp chamber. The bleaching procedure was performed with 35% HP and activated or not with a LED/Laser light. The buffer was mixed with leucocristal violet and peroxide enzyme for the spectrophotometric evaluation of the optical density of the solution. For viability cell assays, different concentrations of HP were applied to fibroblast cell line 3T3/NIH. After 24 h of exposure of HP, the MTT and Neutral Red assays were evaluated. The lethal concentration of 50% of cells (LC50) was determined. Data from each test were submitted to ANOVA and Tukey´s test (α = 0.05). All experimental groups showed HP in the pulp chamber, but higher amount was found in the pulp chamber of teeth with deep restorations (p = 0.026), regardless of light activation. The concentrations of HP that were found in the pulp chamber did not affect cell viability.

Keywords

Tooth bleaching, Hydrogen peroxide, Cytotoxicity.

138

tricalcium phosphate after immersion in cola soft drink

Wermuth SI*¹, Santos PD¹, Genari B1, Leitune VCB1, Collares FM¹, Samuel SMW¹.

1 Dental Materials Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, RS.

Abstract

The aim of this study was to evaluate the influence of immersion in cola soft drink in glass ionomer cement’s surface properties. Two groups were formulated from a commercial restorative glass ionomer cement (Vitremer - 3M, St. Paul, Minesota, USA). The group GCIV was produced from the original material, and the group GCIV from the substitution of 5% by mass of the original cement powder with 5% by mass of αTCP (n=20). The specimens of each group were randomly allocated in two subgroups, depending on they have been immersed in Coca-cola ® or have been immersed only in distilled water (n=10). All specimens were stored in distilled water at 37°C, and the subgroups allocated to Coca-Cola were daily immersed during 1 h in this soft drink. Both roughness, hardness and color stability by CIE L*a*b were evaluated before immersion cycles and after 7 days. Substances’ pH was also evaluated. It was not perceived difference in initial hardness and roughness between groups GCIV and GCIV. After 7 days, GCIV and GCIV had no alteration in roughness, but presented increase in hardness (p<0.05), independently of the immersion solution. Furthermore, color alteration in relation to the initial one (ΔE), had no difference between materials and solutions. Distilled water’s pH was 6.20 and Coca-cola’s was 2.54. Based on these results, it can be realized that the addition of αTCP in glass ionomer cement does not alters its surface properties and that Coca-cola had no interference in these properties.

Keywords

Soft Drinks. Glass Ionomer Cements. Permanent Dental Restoration.

139

Effect to calcium hydroxide on the mechanical properties of root dentin treated

with 2.0% chlorhexidine or 2.5% sodium hypochlorite

Souza SFC*, Ribeiro MRG, Bauer JRO, Tomaz EBAF

1Departamento de Endodontia, 2Departamento de Saúde Coletiva, 3Departamento de Materiais Dentários,

Programa de Pós-graduação em Odontologia, Universidade Federal do Maranhão (UFMA)

Abstract

To evaluate the effect to Calcium Hydroxide (CH) on the mechanical properties of root dentin treated with 2.0%

Chlorhexidine (CHX) or 2.5% Sodium Hypochlorite (NaOCl) after 30, 90 and 180 days. Root dentin bars (DB’s) were

prepared (10x1x1mm) from 90 bovine incisors. The DB’s were randomly divided into three control- (CG’s) and two

experimental groups (EG’s): Deionized and Destilled Water (DDW); NaOCl/EDTA; CHX/DDW; NaOCl/EDTA+CH and

CHX/DDW+CH. The EG’s were subdivided into three subgroups according to the exposure times to CH (T1=30, T2=90 and

T3=180 days). The CG’s were considered baseline (T0). The DB’s were subjected to flexural strength test. The test data

were used to calculate the Ultimate Flexural Strenght (UFS), Modulus of Elasticity (E) and Yield Strength (Off-set 2 %).

The pattern of fractures was evaluated by stereomicroscopic (20x) (α=0.05). For UFS and Off-set 2% the EG2˃EG1 at all

times evaluated (p<0.05), except in T2 for Off-set 2%. For E, EG1=EG2 in T1 and T3, EG2˃EG1 in T0 and T2 (p<0.05). It has

been observed higher frequency of vertical fracture in T3 for EG1 and oblique for EG2 (p<0.05). It was concluded that a

positive synergistic effect between CH and CHX preserved the mechanical properties of root dentin over time.

Key-words: Calcium hydroxide, Chlorhexidine, Sodium hypochlorite, Dentin.

140

Influence of organic acids present in the oral biofilm on durability of

Composite repair bond strength and in their sorption and solubility

Silva S*, Poskus LT, Silva EM, Amaral CM

Analytical Laboratory of Restorative Biomaterials, School of Dentistry, Federal Fluminense University, Niterói, Rio de Janeiro, Brazil.

Abstract

The aim was to evaluate the repair bond strength after storage in lactic and propionic acid for 7 days and 6 months, and the sorption and solubility of composites. Five cylinders of each resin composite (microhybrid, nanofilled and silorane-based composite) were prepared to bond strength test. Specimens were aged with thermocycling (5/55°C) 5000 times. Repair was performed using a sandblasting to air abrasion with 50-µm aluminum oxide plus application of adhesive system Adper Single Bond 2 to microhybrid and nanofilled composite and the Bond of Filtek P90 System Adhesive to silorane-based composite. The new corresponding composite was build-up. Specimens were sectioned in beans and storage in water, propionic acid and lactic acid. After 7 days and 6 months, microtensile bond strength was measured. For sorption and solubility test, 15 specimens (Ø=6mm; h=1mm) of each composite were prepared and assigned into three groups (n=5) according to the immersion media. Data were analyzed using one-way/two-way/three-way ANOVA and Tukey’s test (α=0.05). The resin composites, immersion media and time of immersion did not affect the repair bond strength. The immersion media did not affect the sorption and solubility too. Silorane-based composite presented the lowest sorption and solubility. Regarding solubility, nanofilled and microhybrid methacrylate-based composites did not present statistically difference. These findings showed that repair is a procedure that could be indicates even for areas where presents plaque accumulate.

Keywords

Composite resin, dental plaque, dental restoration repair.

141

Phosphine oxide derivates as alternative photoinitiator for experimental resin-based dental composite

Almeida SM*1, Lovatto ST1, Meereis CTW1, Leal FB1 , Ogliari FA2, Lima GS1. 1 School of Dentistry, Federal University of Pelotas, RS 2 School of Materials Engineering, Federal University of Pelotas, RS

This study evaluated the performance of phosphine oxide derived as photoinitiators to development of dental composites. Bisphenyl (2,4,6-trimethylbenzoyl) - oxide phosphine (BAPO) and diphenyl (2,4,6-trimethylbenzoyl) - oxide phosphine (TPO) were evaluated on the degree of conversion (DC), rate of polimerization (Rp), flexural strength (σ) and elastic modulus (E). Resin composites were formulated with Bis-GMA / TEGDMA (1:1 wt%) and 60% wt% of silanated inorganic particle. The photoinitiators tested were BAPO, BAPO+amine (EDMAB), TPO, TPO+EDMAB and camphorquinone (CQ)+EDMAB (control), using halogen light as photopolimerizer. The DC e Rp was evaluated, in triplicate, by Fourier-transformed infrared spectroscopy FTIR-ATR. For evaluation of σ and E, specimens (n=10) was stored for 24 h at 37º C and submitted to three-point mini-bending test. The data of DC were plotted and curve fitting performed by Hill three-parameter non-linear regression to obtaining Rp. The σ and E were analysed by one-way ANOVA and Holm-Sidak test (p < 0.05). The GC of BAPO (33%), BAPO+EDMAB (28%) and CQ+EDMAB (33%) were similar and higher than TPO (10%) and TPO+EDMAB (10%) after 20 s of photoactivation, however the BAPO obtained the highest Rp. The results of σ (MPa) were statistically similar. The E (GPa) of the CQ+EDMAB (1.7 ± 0.1) was less than BAPO (2.0 ± 0.3) and BAPO+EDMAB (2.0 ± 0.3); and higher than TPO (1.5 ± 0.2) and TPO+EDMAB (1.5 ± 0.2). TPO presented less performance than conventional system (CQ+EDMAB), but BAPO it is a potential photoinitiator for resin-based dental composite.

Keywords

Dental Materials. Photoinitiators. Polymerization.

142

Bond strength of a resin cement to y-tzp and phase transformation after different sandblasting rocatec parameters.

Missau T*1, Pozzobon JL2, Druck CC3, Valandro LF4.

1,2,3,4 School of Dentistry, Federal University of Santa Maria, RS

Abstract

This study evaluated the effect of surface sandblasting parameters (distance and time) on the adhesion between YTZP ceramic and resin-based cements, as well as the t m phase transformation. Forty Y-TZP (In-Ceram YZ, Vita) blocks (4×4×3 mm) were assigned into four groups (n=10), considering the parameters for zirconia surface sandblasting with 110µm particles (Rocatec-Pre) :(T10D10) for 10 seconds and 10 mm in distance between the microetcherhole and YTZP surface; (T10D20) for 10 seconds and 20 mm in distance; (T20D10) for 20 seconds and 10 mm in distance;(T20D20) for 20 seconds and 20 mm in distance. Specimens of composite resin (diameter=3.25mm; height=3mm) were cemented to Y-TZP blocks using resin cement (Relyx ARC). All the specimens were subjected to aging (storage for 90 days and 10,000 thermal cycles) and tested in shear. The tested specimens were analyzed under a stereomicroscope and under SEM. Phase transformation analysis (XDR) was also performed. Bond strength data were submitted to Student tests. For 10mm distance condition, the time had statistical significance (p=0.038), being 10 seconds (12.3 2.1MPa) higher than 20 seconds (10.3 2MPa). For 20mm distance condition, the time was not statistical significance (p=0.6168; T10D20=10.9 2.5MPa, T20D20=10.2 3.2MPa). The phase transformation ranged from 23.78% to 43.69%. The distance factor was not significant, independent from the time. It concludes the sandblasting with10 seconds with 110µm silica particles may promote higher bond strength.

Keywords

Adhesion, Bond strength, Zirconia

143

Influence of colloidal silica and level energy in mechanical properties and shrinkage of composite experimental

Garcia-Silva TC*¹, Souza-Junior EJ¹, Sousa SJ², Brandt WC³, Corer-Sobrinho L¹, Soares CJ², Sinhoreti MAC¹, Consani RLX4

¹ Departament of Restorative Dentistry, Piracicaba Dental School, University of Campinas – UNICAMP, Piracicaba, SP, Brazil ² Departament of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlândia – UFU, Uberlândia, MG, Brazil

³ Departament of Prosthodontics , School of Dentistry, University of Santo Amaro – UNISA, São Paulo, SP, Brazil 4 Departament of Prosthodontics and Periodontics, Piracicaba Dental School, University of Campinas – UNICAMP, Piracicaba, SP, Brazil

Abstract

This study evaluated the effect of the proportion of glass filler particles and colloidal silica in mechanical properties (Knoop hardness (KHN) and modulus of elasticity (E)) and post-gel contraction (GPC) of experimental composites photoactivated with 24J or 48J level of energy. Experimental composite containing BisGMA, BisEMA, UDMA and TEGDMA were manipulated and added camphorquinone / amine as photoinitiator. Composites with filler particles (70 wt%) were evaluated: 100% Ba-Al-Si (C1), the proportion (%) 90:10 Ba-Al-Si / colloidal silica (C2), 80:20 Ba-Al Si / colloidal silica (C3) and 70:30 Ba-Al-Si / colloidal silica (C4). Thus, the bar-shaped specimens were prepared (7x2x1mm). For photoactivation, we used an LED (800 mW/cm²) at two levels of energy (24J and 48J / 30s or 60s). After 24h, KHN was measured in hardness testing machine and E obtained and post-gel shrinkage assessed by Strain Gauges. For statistical analysis, two-way ANOVA and Tukey test (α = 0.05). There was no difference between groups KHN and different levels of energy, since for E was no difference in C2 and C4 with the highest energy. The composites tested showed lower CPG for C1 and C4 than others, when photoactivated with 24J of energy. The 48J of energy promoted higher post-gel contraction to all composites, as compared with the lower dose of energy. The KHN not influenced by protocols evaluated for any group. The E only differed for the C2 and C4 with 48J of energy. The CPG composites C1 and C4 differ from the others in low energy and high energy influence of the CPG all experimental composites.

Keywords

Composite resins, Hardness, Polymerization shrinkage

Funding

--

144

Bond strength of self-adhesive resin cements to artificially-induced caries-affected dentin

Maske TT*1, Peixoto AC2, Bicalho AA3, Isolan CP1, Moraes RR1, Cenci MS1, Soares CJ3, Faria-e-Silva AL2.

1School of Dentistry, Federal University of Pelotas, RS 2School of Dentistry, Federal University of Sergipe, SE 3School of Dentistry, Federal University of Uberlândia, MG

Abstract

The aim of this study was to evaluate the bond strength of two self-adhesive resin cements (RelyX U200 and BisCem), and a regular resin cement (RelyX ARC) to caries-affected dentin induced artificially. A microcosm biofilm from saliva of a donator was formed over dentin samples from 36 caries-free human third molars and cultivated under anaerobic conditions for 14 days. Biofilm model was used with intermittent availability of 1% sucrose in medium culture for 4 h daily. Cylinders of each resin cement were built-up on sound and caries-affected dentin surfaces (n=24). The cylinders were submitted to shear testing after 24 h. Vicker’s hardness (VH, N/mm2) and elastic modulus (E, GPa) were measured in both substrates until the depth of 200 μm using a dynamic microindenter. Bond strength data were submitted to two-way ANOVA followed by Student-Newman-Keuls (SNK) multiple comparisons test, and failure mode was evaluated by Fisher’s Exact and Chi-Square tests. VH and E data were submitted to split-plot ANOVA and SNK’s test (P<0.05). Caries-affected dentin presented lower values of VH and E than sound dentin until the depth of 50 and 100 μm, respectively. Bond strength of all cements was lower to caries-affected dentin than sound dentin. Bond strength of RelyX U200 was similar to RelyX ARC, and both had higher bond strength than BisCem, irrespective of substrate. In conclusion, caries-affected dentin had lower mechanical properties than sound dentin near to surface where the adhesive procedures were performed, imposing challenge to the bond of resin cements.

Keywords

Shear strength; Resin cements; Dental caries

145

Effect of the superficial protection of one commercial glass ionomer cement on its physic-mechanical performance

Priebe T*1, Mirapalhete R1, Isolan CP1, Munchow EA1, Valente LL1, Lacerda HO1, Piva E1.

1School of Dentistry, Federal University of Pelotas, RS.

Abstract

The aim of this study was to investigate the effect of the superficial protection of one glass ionomer cement (GIC) on its flexural strength, flexural modulus, and hardness. Thirty bar-shaped specimens (25x2x2mm) were prepared with the GIC Maxxion R (FGM) and separated in two groups (n=15): experimental (GCC) and control (GSC). After GIC insertion into the mold, specimens from group GCC were maintained at 37°C for 15min, covered with transparent nail polish (Risqué), and finally stored in artificial saliva for 24h; on the other hand, and just after their initial set, specimens from group GSC were directly stored in artificial saliva for 24h. Each specimen was submitted to a three-bend flexural strength test (DL-500, EMIC), and all the fractured specimens were then embedded in epoxy resin, polished, and evaluated by Knoop hardness test (three readings in each specimen). The data were analyzed by t-tests to flexural strength and hardness, and by Mann Whitney to flexural modulus, with 5% level of significance. The mean (standard deviation) are as follow: for flexural strength, in MPa, GCC= 16.7 (7.4)A e GSC= 9.3 (2.9)B; and for hardness, GCC= 76.9 (49.1)A e GSC= 33.7 (11.4)B, and the median for flexural modulus, in GPa, GCC=3,32A e GSC= 2,14B. In conclusion, the superficial protection of the GIC evaluated after its initial set significantly improved all the physic-mechanical properties investigated.

Keywords

Glass Ionomer Cements. Hardness. Elastic Modulus.

146

Effect of the aging methodology on tensile strength value between a resin cement and an indirect resin.

Ferreira TM*1, Miranda RM1, Antunes ANG1, Bonanato K1, Vaz RR1, Vasconcelos WA1

1School of Dentistry, Federal University of Minas Gerais, MG

Abstract

The aim of this pilot study was to evaluate the effect of storage methods on the bond strength between a resin cement and a composite resin. The TPH composite resin (Dentisply) was used to fill a silicone mold (6mm x 10mm) , resulting in two cylindrical blocks . Each base surface were polished with silicon carbide sandpaper (# 600) and coatted with Scotch Bond 2 adhesive (3M ESPE). Fill Magic Dual Cement (Vigodent) was used to cement the two resin blocks. After 24 hours the whole set was sectioned into 15 beams (1mm2 cross sectional area). For the control group, 5 beams (n = 5) were randomly selected and tested under a tensile force (500N and 1mm/min speed). Five beams were randomly selected to form the group of water storage and the remaining 5 assigned to the storage group in alcohol solution. After storage for 2 months, each beam was tested to tensile tension under the same conditions described above. The values were submitted to ANOVA and Tukey at a confidence level of 95 % analysis. The control group, 23.7 ± 6.7 MPa , significantly different to the stored water group (14.2 ± 1.6 MPa , p=0.009) and stored with alcohol group (8.1 ± 2.7 MPa , p <0.05). There was no difference between storage groups (p=0.089). The 2 storage methodologies were able to reduce the value of the bond strength.

Keywords

Resin cement, Tensile strength, Aging.

147

Evaluation of microhardness and roughness in artificial teeth submitted to different procedures for finishing and polishing or lacquer for sealing

Paes-Junior TJA1*, Bonora MS1, Sacorague SCMC1

1 Department of Dental Materials and Prosthodontics, Institute of Science and Technology at São José dos Campos, UNESP - Univ Estadual Paulista, SP

Abstract

The proposal of this study was to verify the roughness surface and microhardness of artificial teeth when submitted to different types of surface treatments. In this case, artificial teeth Classic Heraeus were abraded in 1mm or 2mm depth and submitted to finishing and polishment procedure, according to the following groups: Control group - tooth was abraded and did not receive any type of finishing and polishing; teeth were abraded and submitted to polishing by Trihawk kit; teeth were abraded and submitted to polishing by Viking kit; teeth were abraded and submitted to polishing by sanding strips and sealed by Palaseal adhesive system. Some groups were submitted to 5.000 thermal cycles. To establish the standardization of wear, the teeth were embedded in a PVC with acrylic resin and engaged in a machine polisher, allowing you to control the amount of abraded necessary of the vestibular surface. Specimens were submitted to roughness test (Ra) and hardness Vickers. Data were submitted to 2-way ANOVA and Tukey test, both with α=0.05 for comparison between groups and was possible observed that the Palaseal and control group (2mm depth) showed higher value to roughness. Microhardness test showed the better results to control group (without thermal cycling) and Trihawk (thermal cycled) when abraded in 1mm. It was possible concluded that the quantity of abrasion cause the increase of roughness surface and Trihawk cycled group showed the better result to microhardness, however Palaseal group showed the worst values to roughness when cycled and abraded (1mm).

Keywords

Artificial teeth, Hardness, Dental Polishing

Funding

Research Foundation of the State of São Paulo, FAPESP (process nº2012/21520-0)

148

Evaluation of mechanical properties of an experimental adhesive system containing inhibitors of metalloproteinases

AUTHORS: Carvalho TR*, Rodrigues CUFS, Amaral CM, Silva EM, Matos MPO

Affiliation

LABiom - Laboratory of Biomaterials, School of Dentistry, Fluminense Federal University, Niteroi - RJ

Abstract

The aim of this study was to evaluate the absorption, solubility, degree of conversion (DC) and bond strength (μTBS) to dentin (immediately and after 6 months of storage) of an experimental adhesive system (EXP) containing inhibitors of MMPs (Galardin = GAL, Batimastat = BAT , GM1489 = GM and CHX = chlorhexidine diacetate). For absorption and solubility, samples of each adhesive were prepared and experimental weighed daily until reaching a constant weight. The GC was measured by FT-IR spectroscopy and calculated by the ratio between the area of the signal at 1639 cm-1 to 1609 cm-1 of polymerized and unpolymerized films. For μTBS 36 human molars were used. After applying the adhesive, a block of composite resin was built on the dentin surfaces. After 24 hours of storage in water at 37 ° C, the teeth were cut to obtain sticks 1mm ². Half of toothpicks underwent μTBS immediately, the other half in 6 months. ASB2 was considered the control group. The lowest absorption was observed for CHX. GM, GAL and BAT was similar to ASB2 absorption. EXP absorption was significantly higher than ASB2. With respect to solubility, there were no significant differences between adhesives. All experimental adhesives showed less than ASB2 GC and were able to maintain μTBS after storage for 6 months, but less than ASB2. The addition of MMP inhibitors decreased uptake and did not affect the solubility and GC experimental adhesives. The μTBS experimental dentin adhesives was not reduced after 6 months of storage. Keywords Solubility, Chlorhexidine Funding

FAPERJ

149

Topographic study of the surface of orthodontic archwires composed of stainless steel, nickel titanium and beta titanium alloys.

Holanda TA*1, Pacce MA2, Michelon D, Piva E, Silva RM, Kroning MA.

1School of Dentistry, Federal University of Pelotas, RS

Abstract

Several alloys are used in orthodontic materials and their surface characteristics may decisively influence clinical performance, especially in orthodontic archwires. The aim of this study was to perform measurements of atomic force microscopy (AFM) to provide quantitative information about the roughness at the nanometer level of the three main alloys used in orthodontics: stainless steel (SS), nickel titanium (NiTi) and beta titanium (TMA). Qualitative SEM study was conducted of the surface topography of the archwires. The average surface roughness (Ra) and Maximum Height (Ry) parameters of three specimens of each alloy from five manufacturers were analyzed. The commercially available brands used was Ormco (ORMCO), TP (TP), Morelli (MOR), R & H (RH) and Beijing Smart Technology (BST). Analysis of variance was used second two-way (factors trademarks and alloy type ) and complementary method of Tukey for comparisons between groups (α = 5 %). Just type alloy factor was significant ( p = 0.002 ). Grouped for different types of alloy, independent of trademarks data demonstrated that the TMA alloy (30.73 ± 11.93 , mean ± standard deviation respectively) showed significantly higher values of Ra ( p < 0.05 ) than NiTi ( 16.50 ± 11.96 ) and SS ( 15.19 ± 5.93 ). It was concluded that the arcs of beta titanium alloy have higher roughness which suggests that its use may involve the effectiveness of tooth movement led by arch , the corrosion behavior and aesthetics .

Keywords

Microscopy, Atomic Force , Orthodontic Wires

150

Does the laser improve the clinical success or the pulp healing on pulp exposition?

Silva TM*1, Da Rosa WLO2, Piva E3, Silva AF3

1 Graduate student, School of Dentistry, Federal University of Pelotas, RS, Brazil 2 Master Student, School of Dentistry, Federal University of Pelotas, RS, Brazil 3 Postgraduate Program in Dentistry, Department of Restorative Dentistry, Faculty of Dentistry, Federal University of Pelotas, RS, Brazil

Abstract

The aim of this study was, through a systematic review, to evaluate the effectiveness of the laser as adjunctive therapy on pulpal exposures. The search was conducted in eight databases: MEDLINE ( PubMed ) , Lilacs , IBECS , BBO , Web of Science , Scopus , SciELO and The Cochrane Library. Thus, were included clinical and animal experimental studies which assessed the clinical success rate or the pulp healing, respectively. Initially, 281 studies were identified in all databases. After exclusion of duplicates and analysis, 8 studies were selected by eligibility criteria, it being 3 clinical studies and 5 animal tests. The laser was irradiated prior to insertion of the capping agent. The lasers used were: Diode Laser, CO2, Er: YAG, Er Cr: YSGG and Nd: YAG. Clinical analysis showed, to short and medium term, the laser-treated group showed higher success rate than when compared with the untreated group. Histological analysis revealed that the initial pulp healing was early compared to the untreated group, however, in studies for long periods, it was not achieved consensus among authors. Moreover, it was possible observed that in both models studied the time of application and the type of laser influence in the outcome. It can be concluded that laser therapy seems to contribute to higher rates of initial success, however, studies are required to elucidate the long-term benefits and which of lasers present a better clinical and / or morphological outcome.

Keywords

Laser Therapy, Pulp Capping, Review.

151

Root dentin strain and temperature rise during endodontic treatment and post rehabilitation

Carvalho VF*¹, Amade ES2, Novais VR1, Roscoe MG1, Azevedo FMF1, Bicalho AA1, Soares PBF3, Soares JS1. 1Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlândia, MG. 2Department of Operative Dentistry and Dental Materials, School of Dentistry, School of Science and Technology of Mozambique, MZ. 3Department of Surgery and Traumatology Maxillo-Facial Surgery, School of Dentistry, Federal University of Uberlândia, MG.

Abstract

Endodontic treatment and rehabilitation can change the dentin deformation and heat generation in root surfaces. This study investigated the effects of endodontic treatment procedures and different post systems rehabilitation steps on the strain and temperature rise on apical and cervical root dentin regions. 21 canines were divided into three groups (n=7): FGP, fiber glass post; CPC, cast post-and-core; and PSP, prefabricated steel post. The strain and temperature rise were recorded during the following procedures: root canal preparation, final rinse and drying, root canal filling, canal relief, post-space preparation, post modeling, post trying, and cementation. Data were subjected to a two-way ANOVA followed by Tukey’s test (α=0,05). The values of the temperature variation during the immediate relief in the cervical and apical region were: CPC, 5,2±1,1; 3,2±0,7; PSP, 5,7± 1,7; 2,8±0,8; FGP, 5,5±1,1; 3,7±0,9. The temperature rise reached in post-space preparation procedure was the most dangerous alteration (4.0 – 14.9°C), exceeding the critical values (10°C) even with water irrigation. The average strain (µS) in the cervical and apical, respectively, were: CPC, 215,5±97,6; 217,5±97,6; PSP, 198,2±96,6; 200,0±32,5; FGP, 208,8±92,6; 243,6±131,0. PSP resulted in higher deformation during the trying and cementation. The canal relief and the post-space preparation produced highest temperature rises. These are critical steps and precautions should be taken to avoid mechanical and biological damage to the tooth and the adjacent support structures.

Keywords

Root post, Strain, Temperature

Funding

FAPEMIG

152

Impairment of resin cement application on the bond strength of indirect composite restorations

Poletto-Neto V*1, Porto JAS2, Skupien JA2, Münchow EA2, Cenci MS2, Pereira-Cenci T2

1 School of Dentistry, Federal University of Pelotas, Pelotas, Brazil.

2 Graduate Program in Dentistry, Federal University of Pelotas, Pelotas, Brazil.

Abstract

This study evaluated the impairment of resin cement application on the microtensile bond strength of indirect resin restorations according to cementation and adhesive strategies. Forty-five enamel/dentin discs obtained from bovine teeth were divided into nine groups (n=5). The groups were nominated according to the materials used: R – Regular Cement (RelyX Arc); S – Self-adhesive Cement (RelyX U100); 3 – Three-step Adhesive System (Scotchbond Multi-Purpose); 2 – Two-Step Adhesive System (Adper Single Bond); Im – Immediate Cementation; 5min – 5 minutes of Delayed Cementation; 30min – 30 minutes of Delayed Cementation for groups with Arc and No – Normal Dentin; Dr – Dry Dentin; Mo – Moist Dentin for groups with U100. The microtensile bond strength (μTBS) test was applied using a universal testing machine. Data were analyzed by ANOVA, Tukey’s test and linear regression. Regular cement and three-step etch-and-rinse adhesive system showed the highest values of bond strength (25.21 MPa); however, there was no statistically significant difference for groups that used 3-step adhesive. The same trend occurred for two-step etch-and-rinse adhesive system groups and self-adhesive cement groups. Nevertheless, the linear regression showed that irrespective of the strategy, the use of two-step when compared to three-step adhesive system decreased the μTBS (p<0.001). The failure analysis showed predominant adhesive failures. All groups had comparable values of bond strength to bovine dentin when the same materials were used, even in unfavorable clinical situations.

Keywords

Bonding Agents; Resin Cement; Indirect Restoration.

153

Preliminary results of the survival and fracture load of roots restored with intracanal posts: weakened vs nonweakened roots

Wandscher VF*1, Bergoli CD2, Limberger IF3, Ardenghi TM1, Valandro LF1

1School of Dentistry, Federal University of Santa Maria, RS 2School of Dentistry, Federal University of Pelotas, RS 3School of Mechanical Engeneering, Federal University of Santa Maria, RS

Abstract

This study evaluated the fracture load and survival rate of weakened (WR) and non-weakened roots (NWR) restored with different posts. Eighty teeth (16 mm) were prepared to a length of 10 mm, 50 roots were weakened and 30 were not. The roots were embedded with acrylic resin and the periodontal ligament was simulated. The 50 WR (n=10) were restored with CPC-gold (cast post and core - gold alloy), CPC-Ni (cast post and core - Ni-Cr alloy), FP (glass fiber posts), FP-W (glass fiber posts with a wider coronal diameter), and FP-CR (fiber posts relined with composite resin). The 30 NWR (n=10) were restored with CPC-gold, CPC-Ni, and FP. All the posts were adhesively cemented. All the roots were cycled (37ºC, 45º, 130 N, 2.2 Hz and 1.5 x 106 pulses) and evaluated after every 5 x 104 cycles as the fracture. The specimens that survived cycling were subjected to a fracture load test. Failure mode was classified as favorable and catastrophic. Survival rates were evaluated with Kaplan-Meier method. Fracture load data were analyzed: WR: Kruskal-Wallis, α = 0.05, NWR: one-way ANOVA and Tukey (p < 0.05) and NWR vs WR for the same post: Student t-test (p < 0.05). For the survival results, FP-W showed a higher survival rate when compared with CPC (gold/Ni). For the fracture load, Kruskal-Wallis (p = 0.0001) presented differences for WR: CPC-gold = CPC-Ni > FP = FP-W = FP-RC. No differences were observed for the groups NWR: CPC-gold = CPC-Ni = FP. So, Cast post and cores or fiber posts can be used for restoring NWR and for WR a FP-W appears to be a better alternative when compared with cast post and cores.

Keywords

Survival rate, post and core technique, dental materials

Funding

This study was partially supported by Capes (Brazil).

154

Evaluation of bond strength to dentin of universal adhesives: a systematic review and meta-analysis of in vitro studies

Da Rosa WLO1*, Silva AF2, Piva E2

1 Master Student, Postgraduate Program in Dentistry, Faculty of Dentistry, Federal University of Pelotas, RS, Pelotas, Brazil 2 Professor, Department of Operative Dentistry, Faculty of Dentistry, Federal University of Pelotas, RS, Pelotas, Brazil

Abstract

The universal adhesives can be used with self-etching or conventional technique. The aim of this systematic review was to evaluate whether there is improvement in bond strength to dentin by universal adhesives when used prior acid etching. This study followed the instructions of Prisma Statement. The literature search was conducted until May 2014 in eight databases: PubMed, Web of Science, Scopus, BBO, SciELO, Lilacs, IBECS and The Cochrane Library. It was selected in vitro studies that evaluated the bond strength to dentin of universal adhesives by conventional and self-etching techniques. A global comparison was performed (p=0.01) with fixed-effects and random-effects models. Initially, a total of 3073 studies were identified. After screening all documents, 6 studies were included in the meta-analysis. The values of Cochran‘s Q and I2 tests were p≤0.01 e 94%, while the average value of bond strength by conventional and self-etching technique was, respectively, 36.03MPa and 32.56MPa. The results showed heterogeneity in the comparisons, and no differences were found between the two techniques (p=0:25) with the random-effect model. However, with the fixed-effect model the self-etching technique showed better values in bond strength to dentin (p<0.01). Although the articles showed high heterogeneity, the in vitro literature seems to suggest that there is no improvement in bond strength to dentin by universal adhesives when used prior acid etching.

Keywords

Dental adhesives, dental materials, review

155

Evaluation of resistance of union between infrastructures of zirconia and porcelain of coverage

OLIVEIRA, WLM*²; FREITAS, D. F.²; SERAIDARIAN, P. I¹; MENEZES, L.F.³; JANSEN, W. C.¹

1Professor Adjunto IV do Departamento de Odontologia da Pontifícia Universidade Católica de Minas Gerais – PUCMG, MG.

2Aluno da Graduação do Departamento de Odontologia da Pontifícia Universidade Católica de Minas Gerais – PUCMG, MG.

3Mestre em Clínicas Odontológicas do Programa de Pós Graduação da Pontifícia Universidade Católica de Minas Gerais – PUCMG, MG.

Abstract

Porcelain restorations because of its aesthetics, biocompatibility and resistance have been used instead

of the metal / ceramic with frequency, and the development of infrastructure, with high resistance such

as zirconia, broadened their field for denture partial fixed. The bond strength between veneering

porcelain and ceramic infrastructure determine the longevity of this type of restoration in the oral

environment. The purpose of the current study is to test the bond strength between two infrastructures

zirconia and two types of veneering porcelain. Twenty specimens were made in infrastructure zirconia,

Ceramill ZI® (n = 10) and Lava Frame® (n = 10). The porcelains were applied covering layer and by

condensation and divided into 04 groups: G-1 Lava frame/Vita VM9 (n=5); G-2 Lava frame/e-Max Ceram;

G-3 Ceramill ZI/Vita VM9; G-4 Ceramill ZI/e-Max Ceram. The specimens were subjected to shear test in a

universal testing machine and the results subjected to analysis of variance (ANOVA) to two criterion. The

experiments showed average values of shear force of 792.52N for the G-1 to G-2 741.95N. In Groups 3

and 4 the values were 757.19 and 745.03N, respectively. The results showed no statistically significant

differences between the experimental groups. We can conclude that the type of pottery porcelain factors

and type of coverage did not influence the bond strength.

Keywords

1- Ceramics 2- Dental Materials 3- Bond Strength

156

Influence of pre-silanized glass microfibers on bond strength and nanoleakage of two dentin-bonding agents

Camargo, A, S*; De França, D. M; Vieira, R. M; Klein-Júnior, C. A; Erhardt, M. C. G;

Coelho-de-Souza, F. H. 1Departamento de Odontologia Restauradora, Faculdade de Odontologia, Universidade Federal do Rio Grande do Sul, RS.

ABSTRACT

The aim of this study was to evaluate the microshear bond strength and nanoleakage of two dentin-bonding agents (Adper Single Bond 2 (SB) and Adper Prompt L-Pop (PLP) (3M ESPE) with addition of 10% of pre-silanized glass microfibers. Twelve extracted third molars were used, which had the oclusal enamel totally removed. The modified dentin-bonding agents were applied on the occlusal surface of the teeth, following instructions of the manufacturers. Thus, four groups were obtained: G1 - control SB, G2 - Modified SB, G3 - PLP control and G4 - PLP modified. A 4mm plateau of composite resin was built on the entire area of dentin (Z250-A2 3M ESPE) by incremental technique. The restored teeth were sectioned to obtain sticks (1.2 mm x 1.2 mm 7.0 mm). Two sticks of each group was used for nanoleakage analysis by scanning electron microscopy (SEM). The microshear bond strength was conducted with a cross-head speed of 0.5 mm/min. Data were statistically analyzed by Student's t test, with a significance level set at 5%. The results showed statistically significant differences between G1 and G2 (G1-11.21 MPa +/- 2.69; G2- 18.21 MPa +/- 7.31) and G3 and G4 (G3-6.13 MPa +/- 1.62; G4-18.95 MPa +/- 7.69). The descriptive analysis of SEM images showed less nanoleakage in G2. It is concluded that the addition of 10% of pre-silanized glass microfibers increased the bond strength to dentin of the adhesive systems used and improved the quality of the hybrid layer for Adper Single Bond 2.

Keywords:

Dentin-bonding agents – Composite resins- bond strength

157

Evaluation of different finishing and polishing in temporary filling materials

Reiznautt CM*1, Kreps EL¹, Ribeiro JS¹, Filizola-de-Oliveira DJ¹, Peralta SL¹, Piva E¹, Lund RG¹

Insert affiliation here 1School of Dentistry, Federal University of Pelotas, RS

Abstract

The aim of this study was to evaluate the surface roughness (RA) and the biofilm accumulation (BAT) on temporary materials after different finishing and polishing techniques. The materials tested were: Bioplic (B) and Fermit N (F). Discs (6x1mm) of each material were randomly assigned to one of the following finishing and polishing techniques (n=8): Sof-Lex and (S); polyester strip (P); Glaze (G); or unpolished specimens as control (UP). Profilometer was used to measure the RA before (baseline) and after the biofilm accumulation. For the BAT, eight discs of 6 mm in diameter, were placed into the wells of 24-well plates and a 2-ml volume of BHI supplemented with 10% sucrose and 20 μL of bacteria (1.5 x 108 CFU/ml of S. mutans UA159) were inoculated into each well. After incubation at 37ºC for 72h in an anaerobic chamber, each specimen was sonicated in 1 mL of distilled water and centrifuged, and the supernatants were serially diluted and seeded for posterior determination of the number of viable bacteria. Data were subjected to two-way ANOVA followed by Fisher LSD test (p <0.001). For Ra, both treatment (p=0.001) and material (p=0.001) had statistical difference showing interaction between these variables. G presented statistically lower RA than S, P and UP. For the BAT, there was only statistical differences among techniques (p=0.012), and not for the materials. G presented statistically significant higher biofilm accumulation than S and UP. It was concluded that glazing promoted lowest roughness and highest biofilm accumulation on the materials.

Keywords

Biofilm; polishing; finishing, dental material

158

Comparative analysis of five different techniques of impression in prosthesis implant FREITAS, D. F.²*; OLIVEIRA, WLM²; SERAIDARIAN, P. I¹; RIBAS, F. L.³; JANSEN, W. C.¹

1Professor Adjunto IV do Departamento de Odontologia da Pontifícia Universidade Católica de Minas Gerais – PUCMG, MG.

2Aluno da Graduação do Departamento de Odontologia da Pontifícia Universidade Católica de Minas Gerais – PUCMG, MG.

3Mestre em Clínicas Odontológicas do Programa de Pós Graduação da Pontifícia Universidade Católica de Minas Gerais – PUCMG, MG.

Abstract

The aim of this experimental study was to compare five different direct techniques of molding in implant

(n = 5): group 1-transferents separate group 2-transferees together with acrylic resin, group 3-transferees

together with acrylic resin, targeted and united again acrylic resin group, 4-transferents coated with the

adhesive of the molding material and the 5-transferents together with acrylic resin, separated and united

again with cyanoacrylate and a tube of latex analogous to provide a double plaster casting. To this end,

we fabricated an array of acrylic resin which were fixed on four analogs with implant platform 4.1 mm

external hexagon. The implants were molded using the individualized impression tray, acrylic and

polyether. In total 25 models with 100 measurements. All measurements were made using a comparison

microscope.

The average misfit measures were: 6.42 μm for group 1, group 2 in 11.53 μm, in group 3 was 7.3 μm and

in groups 4 and 5, 5.12 and 6.10 μm respectively. There was no statistically significant difference between

the groups with transferees united and not united. The worst results were shown by group 2.

Keywords

1- Dental Prosthesis 2- Dental Materials 3- Dental Impression Materials

159

Surface roughness and candida adhesion on composite provisional restorative materials Ribeiro JS*1, Oliveira DJF1, Torre EN¹, Peralta SL¹, Piva E¹, Lund RG¹.

1School of Dentistry, Federal University of Pelotas, RS

Abstract

The aim of this study was to evaluate the surface roughness (SR) and the biofilm accumulation test (BAT)

of different composite provisional restorative materials. The materials tested were: Access Crown (AC);

Duralay (D); Protemp (P); Systemp (S); and Revotek LC (R). Eight discs (6x1mm) of each material was

prepared. Profilometer was used to assess the mean SR before and after the BAT. Candida albicans ATCC

62342 inoculum was used for the BAT. Eight discs of 6 mm diameter was placed into the cavities of a 24-

wells plate. A 2-mL vol of Sabouraud dextrose (SD) broth supplemented with 1% sucrose and 20 μL of

fungal suspension had inoculated into each well. After incubation at 37ºC for 24h in an aerobic chamber,

each specimen was sonicated in 1 mL of distilled water and the suspension was serially diluted and plated

on SD agar to determine the number of viable fungi cells. Data were subjected to ANOVA and two-way

ANOVA, followed by a post hoc test (p<0.05). SR showed statistical differences regarding the material

(p=0.001), but no difference regarding time was found (p=0.199), and there is interaction between these

variables(material x time) (p=0.043). D showed higher value of SR than the other materials. For the BAT

assay, AC showed higher value of CFU (Colony-Forming Units) when compared with other groups. The

results showed that the adhesion and biofilm formation of of C. albicans was determined by the material,

followed by the surface roughness except for AC that showed greatest biofilm formation although it did

not presented the highest values of roughness.

Keywords

Biofilm; dental material

160

Influence of stick location and cycling method on the micro-tensile bond strengths

Correr-Sobrinho L*1, Costa AR1, Correr AB1, Sinhoreti MAC1, Soares CJ2 Garcia-Godoy F3, Versluis A3

1Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, SP

2 Department of Operative Dentistry and Dental Materials, Federal University of Uberlândia, MG

3 Department of Bioscience Research, College of Dentistry, University of Tennessee, Memphis, TN

The objective of this study was evaluate if micro-tensile bond-strength was affected by the stick location and cycling method. Fifteen ceramic blocks IPS e.max Press (7x7x5mm) were cemented to composite blocks Tetric N-Ceram. Ceramic surfaces were etched 10% hydrofluoric acid for 20s, the silane was applied and blocks were cemented to the composite blocks with resin cement RelyX ARC and light-activated for 40s. After 24hr, the blocks were divided into 3 groups (N=5): control, thermal fatigue (3,000 thermal cycles (5oC and 55°C), and mechanical fatigue 250,000 mechanical cycles. Afterwards all blocks were cut into 25 sticks with area of 1mm2 cross-sections, and labeled I-V with increasing distance to the center (I=center, V=outermost-corners). Micro-tensile bond strength was determined at 0.5mm/min cross-head speed. Results were analyzed using ANOVA followed by Student-Newman-Keuls post-hoc (p=0.05). The value of micro-tensile bond strength (MPa) was: control: stick location I (42±5), II (37±14), III (28±12), IV (29±10) e V (31±8), thermal fatigue I (31±7), II (28±9), III (27±9), IV (21±7) e V (21±6) and mechanical fatigue I (10±3), II (19±7), III (19±6), IV (22±9) e V (23±10). The thermal fatigue, mechanical fatigue and stick location affected bond-strength results. Highest bond-strengths were found for center sticks (I), except after mechanical fatigue loading, which significantly reduced bond strengths of sticks around the center (I-III). At the outer-surface (IV-V) the results after thermal or mechanical fatigue were not different.

Ceramic, Dental Cements, Dental Materials

CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior), Proc: 3463-10-9.

161

Addition of hydroxyethyl acrylamide in the properties of an experimental adhesive resin Rodrigues SB*1, Leitune VCB1, Ogliari FA2, Petzhold CL3, Samuel SMW1, Collares FM1.

1Dental Materials Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil. 2 Materials Engineering School, Federal University of Pelotas, RS, Brazil. 3Organic Chemistry Department, Chemistry Institute, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.

Abstract

The purpose of this study was to develop an experimental adhesive resin using hydroxyethyl acrylamide (HEAA). Three experimental resin were formulated, GHEAA33% (33.3% HEAA + 66.6% Bisphenol A glycerolate dimethacrylate- BisGMA), GHEAA50% (50% HEAA + 50% BisGMA), and GHEMA (33.3% 2-Hydroxyethyl methacrylate- HEMA + 66.6% of BisGMA). Flexural strength (n= 12), swelling degree (n= 3), glass transition temperature (Tg-n= 3), and softening in solvent (n= 5) were evaluated for each adhesive resin. The polymerization process were evaluated using differential scanning calorimetry (DSC-n= 3), as well as for the homopolymers, BisGMA, HEMA, HEAA, HEMA* without ethyl 4-dimethylaminobenzoate (EDAB), and HEAA* without EDAB. For all resins and homopolymers evaluated, except for homopolymers HEMA, HEMA* and HEAA*, a high rate of polymerization and a high degree of conversion were observed. There was no significant difference (p > 0.05) for the Tg and softening in solvent for the adhesive resins assayed. The GHEAA33% group exhibited less swelling degree (p < 0.05) and reduced flexural strength (p < 0.05) compared to the GHEMA group. The addition of hydroxyethyl acrylamide in an experimental adhesive resin increases the polymerization process, thus it could be an alternative for adhesive resins.

Keywords: Dentine-bonding agents, acrylamides, hydroxyethyl methacrylate

162

Biological effect of contemporary adhesive systems

Rossato TCA*1,Oliveira DJF²,Oliveira HL³, Torre EN4,Peralta SL5, Etges A6, Lund RG7

1School of Dentistry, Federal University of Pelotas, RS – tharsisc@yahoo.com.br 2School of Dentistry, Federal University of Pelotas, RS – dfilizola@gmail.com 3School of Dentistry, Federal University of Pelotas, RS – hellen.loli@gmail.com 4School of Dentistry, Federal University of Pelotas, RS – eliana_torre@hotmail.com 5School of Dentistry, Federal University of Pelotas, RS – solupe@gmail.com 6School of Dentistry, Federal University of Pelotas, RS – aetges@gmail.com 7School of Dentistry, Federal University of Pelotas, RS – rafael.lund@gmail.com

Abstract

This study aimed to evaluate the cytotoxicity (CT) and the antibacterial effect by direct contact test (DCT) of four adhesive systems: Adper Single Bond (SB); Adper Scotchbond Multiporpuse (SBM); Single Bond Universal (SBU); Clearfil SE Bond (CSE); and Clearfil Protect Bond as control (PB). It was assessed the primer+bond (p+b) and only bond (b). For the CT, human keratinocytes (HaCat) were used. The specimens were immersed in RPMI culture medium for 24h for the extraction of eludates. The CT was evaluated by MTT colorimetric assay. The DCT was evaluated against S. mutans UA159, E. faecalis ATCC4083, and S. aureus ATCC19095. For DCT, adhesive systems were applied to the sidewalls of a 96-well plate and cured for 20 s; then, 10μl of the suspension (BHI + S. mutansor E. faecalis or S. aureus) were placed and, subsequently, they were incubated for 1 and 24h. Then, the reaction mixtures were taken for reading in spectrophotometer. Data were subjected to two-way ANOVA followed by Fisher LSD test for DCT, and Kruskall Wallis for CT (p<0.001). For DCT, PB (p+b), SB and PB showed higher antimicrobial activity against S. mutans (p<0.001); SBM (b) and SB were similar to PB (p=0.003) against E. faecalis; and all groups was similar (p<0.001) against S. aureus, except for SBM (p+b) and CSE. The results of CT showed that SB and PB were statistically similar to the control group, while the other groups were more cytotoxic. It was concluded that even adhesive systems with no antimicrobial components showed some antimicrobial effect and, for the cytotoxicity, the SB and PB (b) was similar to control.

Keywords

Cytotoxicity Tests, Immunological; Bacterial Growth; Dental Adhesives.

163

Translucency of different materials used as infrastructure for ceramic fixed partial dentures

Borba M1*, Sonza QN2, Girotto A1.

1School of Dentistry, University of Passo Fundo, RS 2 FASURGS, Passo Fundo, RS.

Abstract

The objective of this study was to evaluate the translucency of different materials used as infrastructure (IE) for ceramic fixed partial dentures. Three IE materials were evaluated: (MC) NiCr alloy; (IZ) alumina-based, zirconia reinforced, glass-infiltrated ceramic (In-Ceram Zirconia); (YZ) yttria stabilized polycrystalline tetragonal zirconia. Square-shaped specimens (2 mm x 2 mm x 0.5 mm) were produced by sectioning CAD-CAM ceramic blocks with a cutting machine (IZ and YZ) and by the conventional casting technique (MC) (n=8). IZ specimens were glass-infiltrated and YZ specimens were sintered, according to the manufacturer instructions. All specimens were polished with 600, 800 and 1200 grit-paper, previously to the analyses. Specimen reflectance was measured using a spectrophotometer (Konica Minolta CM3700D). Contrast Ratios (CR) were calculated from the luminous reflectance of the specimens with a black and a white background, with CIE illuminant D65 and a 2-degree observer function (0.0 = transparent, 1.0 = opaque). Kruskall-Wallis and Dunn’s tests were used to analyze the data with 5% significance level. Statistically significant differences were observed for CR values among groups (p=0.002). MC (0.94) and IZ (0.99) groups showed similar CR values and higher than YZ group (0.82). It was concluded that In-Ceram Zirconia ceramic has similar opacity to the metal. On the other hand, Y-TZP ceramic shows higher translucency than the other evaluated materials. Keywords

Ceramics. Color. Prosthesis.

Funding

164

Evaluation of fracture resistance of cad-cam crowns luted to solid pillars

Stona D, Mildner MD*, Burnett Junior LH1, Spohr AM2

1School of Dentistry, PUCRS 2School of Dentistry, PUCRS

The aim was to evaluate the fracture resistance of ceramic crowns using Cerec CAD-CAM system on solid pillars. Sixty replica synocta implant and RN solid abutment were embedded in acrylic resin, being randomly assigned (n=20 per group). The ceramics Mark II, IPS Empress CAD and IPS e.max CAD were used. The crowns were fabricated by CAD-CAM system using the Cerec software version 4.1, and the crowns were cemented with RelyX U200 resin cement. Half of the specimens was submitted to fracture resistance test in a universal testing machine, and the other half after 1,000,000 cyclic fatigue loading at 100 N. According to two-way ANOVA, the interaction between the material and mechanical cycling was significant (p = 0.0001). According to Tukey test, the fracture resistance without and with cyclic loading, respectively, of Mark II (405N/454N) was statistically lower than IPS Empress CAD (1169N/1240N) and IPS e.max CAD (1378N/1025N) (p<0.05). The ceramics IPS Empress CAD and IPS e.max CAD did not differ statistically between them (p>0.05). According to student t-test, there was no statistical difference in the fracture resistance with and without cyclic loading for Mark II and IPS Empress CAD (p>0.05). For IPS e.max CAD, the fracture resistance without cyclic loading was statistically superior to that obtained with cyclic loading (p<0.05). The ceramic IPS Empress CAD and IPS e.max CAD showed higher fracture resistance compared to Mark II. The cyclic loading negatively influenced only IPS e.max CAD.

ceramics, fracture resistance, dental implant

165

Characterization of a glass ionomer cement containing calcium phosphates

Santos PD*1, Wermuth SI1, Silva FL1, Garcia IM1, Leitune VCB1, Collares FM1, Samuel SMW1.

Insert affiliation here 1 Dental Materials Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, RS.

Abstract

Dentin’s remineralizator pontential seems to complement glass ionomer’s known benefits, specially in clinical situations of partial dentin removal, as long as it does not harm the materials1’s original properties. The aim of this study was to evaluate the effect of the addition of Octacalcium phosphate (OCP), tricalcium phosphate ( TCP) or nanostructuracted hydroxyapatite (HA) on the properties of a commercial restaurative glass ionomer cement (Vitremer - 3M, St. Paul, Minesota, USA), considering comments in academic literature on the remineralizator potential of those materials. The proposed test groups, GOCP, GTCP e GHA, were composed by substituting 5%, by mass, of original cement powder with 5%, by mass, of OCP, of TCP or of HA, respectively. The group GCIV, without alteration, was the control group. Groups were submitted to initial hardening time and radiopacity evaluation according to ISO 9917-2:2003. The results of hardening time were 39.06 (+ 1.15) min for GCIV, 42.64 (+ 8.64) for GHA, 54.17 (+ 1.23) min for GOCP and 58.39 (+ 2.64) min for GTCP, conforming to specification. Regarding radiopacity, there was no statistically significant difference. Furthermore, all groups presented results according to specification and presented radiopacity equivalent to 3mmAl. Thus, it can be supposed that the addition of calcium phosphates appear to be a promising way to enhance the benefits of glass ionomer cements.

Keywords

Glass Ionomer Cements. Permanent Dental Restoration.

166

All-ceramic in vitro test: insights to an ideal scenario to reproduce clinical Benetti P, Meirelles PD *, Della Bona A, Kelly JR

1School of Dentistry, University of Passo Fundo, RS

Abstract

Randomized clinical trials are adequate to evaluate the longevity of restorations. However, there are some limiting factors such as operational cost, observation time, number and collaboration of patients and a lot of organizational effort. Therefore, developing laboratory tests to predict the clinical behavior of materials and structures is important. However, predicting the clinical performance from laboratorial tests is still a challenge. Since many in vitro approaches provide little association to clinical condition, the aim of this study is to describe an in vitro scenario to test ceramic crowns producing loads, stress distribution and fracture patterns that are clinically meaningful. Thus, data was extracted from 455 papers published between 1985 and 2012. The descriptors used were: crown, fracture and ceramic; the inclusion criteria were: in vitro tests, and all-ceramic crowns; the exclusion criteria were: repair, posts and implants. The following aspects were considered important to an ideal scenario and service simulation: (1) presence of water, which propagates pre-existing cracks; (2) fatigue, which has an effect on the mechanical stability; (3) dentin substrate or analog material, to simulate the elastic behavior; (4) a 3-mmcontact area for the piston, which reproduces clinical occlusal contact area; and (5) early detection of fracture, observed by sound emission, change in the stress-strain curve and transillumination.

Keywords: Ceramics, Dental Restoration , In vitro