Avaliação imediata e após 6 meses da resistência de união a dentina de restaurações de resina composta classe I in vivo e in vitro

Pós-graduação em Odontologia Restauradora - ICT

Repair bond strength of microhybrid, nanohybrid and nanofilled resin composites: Effect of substrate resin type, surface conditioning and ageing

Objectives: This study evaluated the microtensile bond strength (MTBS) of non-aged and aged resin-based composites (RBC) (nanohybrid and nanofilled) after two surface conditioning methods, repaired using the composite of the same kind or a microhybrid composite. Materials and methods: Nanohybrid (Tetric EvoCeram-TE) and nanofilled (Filtek Supreme-FS) RBC blocks (5 × 5 × 6 mm) (N = 128) were fabricated and randomly divided into two groups: (a) no ageing (control group) and (b) ageing (5.000 thermocycling, 5-55 °C). RBC surfaces were polished by up to 1,200-grit silicone carbide papers and conditioned with either (a) air abrasion with 30-μm SiO2 particles (CoJet Sand) for 4 s + silane coupling agent (ESPE-Sil) + adhesive resin (VisioBond) (n = 16) or (b) adhesive application only (Multilink A+B for TE; Adper ScotchBond 1XT for FS) (n = 16). In half of the groups, repair resin of the same kind with the RBC and, in the other half, a different kind of composite (microhybrid, Quadrant Anterior Shine-AS) with its corresponding adhesive (Quadrant UniBond) was used. The specimens were submitted to MTBS test (0.5 mm/min). Data were analysed using three-way ANOVA and Tukey's tests. Degree of conversion (DC) of non-aged and aged resin composites (TE, FS) (n = 3 per group) was measured by micro-Raman analyses. Results: RBC type (p = 0.001) and ageing affected the MTBS results significantly (p = 0.001). Surface conditioning type did not show significant difference (p = 0.726), but less number of pre-test failures was experienced with the CoJet system compared to adhesive resin application only. Repair strength on aged TE showed significantly less (p < 0.05) MTBS than for FS. FS repaired with the same kind of RBC and adhesive resin presented the highest cohesive failures (43 %). DC was higher for TE (71 %) than for FS (58 %) before ageing. Conclusion: On the aged RBCs, less favourable repair strength could be expected especially for nanohybrid composite. For repair actions, RBC surface conditioning could be accomplished with either adhesive resin application only or with CoJet system, providing that the latter resulted in less pre-test failures. Clinical relevance: Clinicians could condition the resin surface prior to repair or relayering with either CoJet system or adhesive resin application only, depending on the availability of the system. © 2012 Springer-Verlag Berlin Heidelberg.

Effect of fluid resins on the surface roughness and topography of resin composite restorations analyzed by atomic force microscope

The aim of the study was to verify the influence of surface sealants on the surface roughness of resin composite restorations before and after mechanical toothbrushing, and evaluate the superficial topography using atomic force microscope. Five surface sealers were used: Single Bond, Opti Bond Solo Plus, Fortify, Fortify Plus and control, without any sealer agent. The lowest values of surface roughness were obtained for control, Single Bond and Fortify groups before toothbrushing. Fortify and Fortify Plus were the sealer agents that support the abrasive action caused by the toothbrushing although Fortify Plus group remained with high values of surface roughness. The application of specific surface sealants could be a useful clinical procedure to maintain the quality of resin-based composite restorations. (C) 2010 Elsevier Ltd. All rights reserved.

Assessing the surface roughness of a posterior resin composite: effect of surface sealing

This study assessed the in vitro influence of surface sealing on the surface roughness of a posterior resin composite before and after tooth-brushing. Thirty. specimens (13 nun diameter x 1 mm high) were fabricated from Filtek-P60 resin composite and randomly assigned to three groups (n=10): a non-sealed control and two groups sealed with one of the tested materials-a surface-penetrating sealant (Protect-it!-PI) and a one bottle adhesive system (Single Bond-SB). The samples were subjected to a surface roughness reading to determine the initial roughness, then submitted to simulated toothbrushing with 35,600 cycles for 100 minutes. Specimens were then cleaned and a post-abrasion surface roughness reading accomplished. Means (pm), recorded before (B) and after (A) toothbrushing, and standard deviations were: Control-(B): 0.032 (+/-0.005), (A): 0.054 (+/-0.005); PI-(B): 0.034 (+/-0.005), (A): 0.060 (+/-0.034); SB (B): 0.031 (+/-0.004), (A): 0.047 (+/-0.007). Data were tabulated and submitted to two-way ANOVA. No statistically significant difference was observed when the control and experimental groups were compared. However, a significant difference (p<0.05) was found between the measurements performed before and after toothbrushing. Based on these results, it may be concluded that using either a surface penetrating sealant or a one bottle adhesive system did not provide the optimization of superficial integrity. The use of a dentifrice and toothbrush resulted in significant alterations to the surface smoothness of the resin composite.

Deposition of Lead and Cadmium Released by Cigarette Smoke in Dental Structures and Resin Composite

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Bond strength durability of a resin composite on a reinforced ceramic using various repair systems

Objectives. This study compared the durability of repair bond strength of a resin composite to a reinforced ceramic after three repair systems.Methods. Alumina-reinforced feldspathic ceramic blocks (Vitadur-alpha(R)) (N=30) were randomly divided into three groups according to the repair method: PR-Porcelain Repair Kit (Bisco) [etching with 9.5% hydrofluoric acid + silanization + adhesive]; CJ-CoJet Repair Kit (3M ESPE) [(chairside silica coating with 30 mu m SiO2 + silanization (ESPE(R)-Sil) + adhesive (Visio(TM)-Bond)]; CL-Clearfil Repair Kit [diamond surface roughening, etching with 40% H3PO4 + Clearfil Porcelain Bond Activator + Clearfil SE Bond)]. Resin composite was photo-polymerized on each conditioned ceramic block. Non-trimmed beam specimens were produced for the microtensile bond strength (mu TBS) tests. In order to study the hydrolytic durability of the repair methods, the beam specimens obtained from each block were randomly assigned to two conditions. Half of the specimens were tested either immediately after beam production (Dry) or after long-term water storage (37 degrees C, 150 days) followed by thermocyling (12,000 cycles, 5-55 degrees C) in a universal testing machine (1 mm/min). Failure types were analyzed under an optical microscope and SEM.Results. mu TBS results were significantly affected by the repair method (p=0.0001) and the aging conditions (p=0.0001) (two-way ANOVA, Tukey's test). In dry testing conditions, PR method showed significantly higher (p < 0.001) repair bond strength (19.8 +/- 3.8 MPa) than those of CJ and CL (12.4 +/- 4.7 and 9.9 +/- 2.9, respectively). After long-term water storage and thermocycling, CJ revealed significantly higher results (14.5 +/- 3.1 MPa) than those of PR (12.1 +/- 2.6 MPa) (p < 0.01) and CL (4.2 +/- 2.1 MPa) (p < 0.001). In all groups when tested in dry conditions, cohesive failure in the composite accompanied with adhesive failure at the interface (mixed failures), was frequently observed (76%, 80%, 65% for PR, CJ and CL, respectively). After aging conditions, while the specimens treated with PR and CJ presented primarily mixed failure types (52% and 87%, respectively), CL group presented mainly complete adhesive failures at the interface (70%).Significance. Hydrolytic stability of the repair method based on silica coating and silanization was superior to the other repair strategies for the ceramic tested. (C) 2009 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Effect of Carbamide Peroxide Bleaching Gel Concentration on the Bond Strength of Dental Substrates and Resin Composite

Purpose: This study evaluated the effect of bleaching gel containing 10%, 15% and 20% carbamide peroxide (CP) on the bond strength of dental enamel or dentin and resin composite restorations.Methods: The buccal surfaces of 12 bovine tooth crowns were conditioned with 37% phosphoric acid, and the adhesive resin Single Bond 2 and the resin composite Filtek Z350 were used to perform the restorations. The blocks were sectioned to obtain bar specimens. Each specimen group (enamel-E, dentin-D) was divided into four subgroups (n=15): S-artificial saliva; 10-10% CP bleaching; 15-15% CP bleaching; 20-20% CP bleaching. CP was applied for six hours daily for two weeks. The specimens were submitted to the a test in a universal testing machine. The data were analyzed by one-way ANOVA and the Tukey post-hoc test and a correlation analysis (r) was performed.Results: For Group E, the mean value (+/- standard-deviation) was 21.86 (+/- 6.03)a, 18.91 (+/- 8.31)ab, 15.43 (+/- 7.44)b and 10.6 (+/- 4.94)c for ES, E10, E15 and E20, respectively. For Group D, the alpha values were 34.73 (+/- 4.68)a, 35.12 (+/- 13.43)a, 29.67 (+/- 6.84)ab and 24.56 (+/- 6.54)b for DS, D10, D15 and D20, respectively. A negative correlation between the CP concentration and mean values was observed for both the enamel (r=-0.95) and dentin (r=-0.85) groups.Conclusion: In the current study, the bond strength of the restoration to enamel and the restoration to dentin were influenced by the application of CP and was dependent on the CP concentration in the bleaching gel.

A retrospective look at esthetic resin composite and glass-ionomer Class III restorations: A 2-year clinical evaluation

Objective: A restorative material for Class III cavities must, besides being functional, be esthetically satisfactory, providing good working conditions and several shade and color options. A clinical evaluation was initiated to compare the suitability of resin composite and glass-ionomer cement materials for such restorations.Method and materials: Forty-two Class III conservative cavities, esthetically important because of facial extensions, were selected. Resin composite restorations were placed in 21 cavities, and the remaining 21 were restored with glass-ionomer cement. The following characteristics were studied: color or-esthetics, anatomic shape, surface texture, staining, marginal infiltration, dental plaque retention, and occurrence of fracture. After 24 months, the restorations were evaluated.Results: the only statistically significant difference between the resin composite and glass-ionomer cement restorations in the experimental period involved color or esthetics.Conclusion: Resin composites and glass-ionomer materials provide excellent functional and esthetic results in Class III cavities when properly indicated.

Effect of dental surface treatment with Nd:YAG and Er:YAG lasers on bond strength of resin composite to recently bleached enamel

The aim of this work is to evaluate the effect of surface treatment with Er:YAG and Nd:YAG lasers on resin composite bond strength to recently bleached enamel. In this study, 120 bovine incisors were distributed into two groups: group C: without bleaching treatment; group B: bleached with 35% hydrogen peroxide. Each group was divided into three subgroups: subgroup N: without laser treatment; subgroup Nd: irradiation with Nd:YAG laser; subgroup Er: irradiation with Er:YAG laser. The adhesive system (Adper Single Bond 2) was then applied and composite buildups were constructed with Filtek Supreme composite. The teeth were sectioned to obtain enamel-resin sticks (1 x 1 mm) and submitted to microtensile bond testing. The data were statistically analyzed by the ANOVA and Tukey tests. The bond strength values in the bleached control group (5.57 MPa) presented a significant difference in comparison to the group bleached and irradiated with Er:YAG laser (13.18 MPa) or Nd:YAG (25.67 MPa). The non-bleached control group presented mean values of 30.92 MPa, with statistical difference of all the others groups. The use of Nd:YAG and Er:YAG lasers on bleached specimens was able to improve the bond strengths of them.

Surface roughness of enamel and four resin composites

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evaluation of the Cohesive Strength Between Resin Composite and Light-curing Characterizing Materials

Purpose: To evaluate the cohesive strength between composite and different light-curing characterizing materials (LCCM), which were prepared using the intrinsic technique.Materials and Methods: One hundred composite specimens were made by using a prefabricated Teflon device, and a layer of LCCM was applied at the interface. The specimens were divided into 5 groups (n = 20): group 1 (control), no LCCM was used; group 2: application of White Kolor Plus Pigment (Kerr) LCCM; group 3: White Tetric Color Pigment (Ivoclar/Vivadent) LCCM; group 4: Brown Kolor Plus Pigment (Kerr) LCCM; group 5: Black Tetric Color Pigment (Ivoclar/Vivadent) LCCM. All materials were used according to the manufacturers' instructions. Specimens were submitted to a tensile test in a universal testing machine (EMIC DL-200MF) to evaluate the cohesive strength at the composite interface. Data were subjected to one-way ANOVA and Tukey's test (alpha = 5%).Results: ANOVA showed a p-value = 0.0001, indicating that there were significant differences among the groups. The mean values in MPa (+/- standard deviation) obtained for the groups were: G1: 28.5 (+/-2.74)a; G2: 23.5 (+/-2.47)b; G3: 20.3 (+/-2.49)b; G4: 10.5 (+/-2.40)c; G5: 9.66 (+/-3.06)c. The groups with the same letters presented no significant differences. The control group presented statistically significantly higher cohesive strengths when compared to the other groups. The groups in which Brown Kolor Plus Pigment and Black Tetric Color Pigment LCCM were used showed significantly lower cohesive strengths when compared to the groups in which White Kolor Plus Pigment and White Tetric Color Pigment LCMM were used.Conclusion: The use of LCCM produced with the intrinsic technique reduced the cohesive strength of composite.

Polymerization shrinkage: effects of boundary conditions and filling technique of resin composite restorations

Objective: To evaluate the linear polymerization shrinkage (LPS) and the effect of polymerization shrinkage of a resin composite and resin-dentin bond strength under different boundary conditions and filling techniques.Methods: Two cavities (4 x 4 x 2 MM) were prepared in bovine incisors (n = 30). The teeth were divided into three groups, according to boundary conditions: In group TE, the total-etch technique was used. In group EE, only enamel was conditioned, and in group NE, none of the watts of the cavities were conditioned. A two-step adhesive system was applied to all cavities. The resin composite was inserted in one (B) or three increments (1), and tight-cured with 600 mW/cm(2) (80 s). The LPS (%) was measured in the top-bottom direction, by placing a probe in contact with resin composite during curing. Enamel and total mean gap widths were measured (400 x) in three slices obtained after sectioning the restorations. Then, the slices were sectioned again, either to obtain sticks from the adhesive interface from the bottom of the cavity or to obtain resin composite sticks (0.8 mm(2)) to be tested for tensile strength (Kratos machine, 0.5 mm/min). The data was subjected to a two-way repeated measures ANOVA and Tukey's test for comparison of the means (alpha = 0.05).Results: the highest percentage of LPS was found for the TE when bulk fitted, and the lowest percentage of LPS was found in the Hand NE when incrementally fitted. The resin dentin bond strength was higher and the total mean gap width was tower for TE group; no significant effect was detected for the main factor fitting techniques. No difference was detected for the tensile strength of resin composite among the experimental groups.Conclusions: the filling technique is not able to minimize effects of the polymerization shrinkage, and bonding to the cavity watts is necessary to assure reduced mean gap width and high bond strength values. (C) 2004 Elsevier Ltd. All rights reserved.