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Purpose: To determine the degree of conversion (DC), physicochemical properties, and microshear bond strength (μSBS) of experimental self-adhesive resin cements (SARCs) to dentin and yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramic. Materials and Methods: Dual-curing cements were formulated with UDMA, HEMA, bis-GMA, and TEG-DMA as the organic matrix. 2MP (bis 2-(methacryloyloxy)-ethyl-phosphate) and GDMAP (1,3-glycerol dimethacrylate phosphate) were added to impart self-adhesive characteristics. A control group was formulated without self-etch methacrylates. Silanized particles were incorporated. Photoactivation was carried out using an LED light-curing unit (1200 mW/cm2) for 20 s. Infrared spectroscopy assessed the DC immediately and after 24 h. pH was analyzed in real time and recorded after 48 h. Water sorption (Wsp), water solubility (Wsl), and film thickness measurements followed ISO 4049. μSBS of the cements to dentin and Y-TZP was evaluated immediately and after 3 months of water storage. Y-TZP was also tested without a surface treatment and after tribochemical silica coating with subsequent application of a silane agent. The fractures patterns were classified as adhesive, cohesive, and mixed. Data were submitted to analyses of variance and Tukey's tests (α = 0.05). Results: Control (91.7%) and 2MP (92.0%) groups generated the highest DC after 24 h. 2MP (pH = 3.6) showed the lowest pH followed by GDMAP (pH = 4.7) and control (pH = 6.4) after 48 h. The control cement exhibited lower Wsp (41.0 μg/mm³) and Wsl (4.3 μg/mm3) than the other groups. Film thickness was statistically similar (p = 0.266) for all cements. Control (27.0 MPa) and GDMAP (24.1 MPa) showed higher μSBS to dentin than 2MP (13.7 MPa) after water storage. Mixed fractures were predominant in dentin. For all cements, the μSBS to Y-TZP was < 3.0 MPa after water storage, independent of the surface treatment. Conclusion: The results of DC, pH, Wsp and Wsl were material dependent. Only the film thickness was statistically similar for all groups. The cement formulated with GDMAP maintained the bond strengths to dentin even after aging. However, none of the groups were able to generate satisfactory bond strength to Y-TZP, independent of the surface treatment. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate the tensile bond strength (TBS) of repairs in recent fillings of methacrylate- (MBC) or silorane-based composites (SBC) subsequent to different surface treatments. Materials and Methods: Fifty slabs of Filtek P60 (3M ESPE, St Paul, USA) and Filtek P90 (3M ESPE) were stored for 10 days in distilled water at 37°C. The surface of adhesion was abraded with a 600-grit silicone paper and repaired using each respective composite: G1, no treatment (control); G2, application of adhesive; G3, application of silane and adhesive; G4, sandblasting (Al2O3) and adhesive; and G5, sandblasting (Al2O3), silane, and adhesive. Further 10 slabs of each composite were also evaluated for cohesive strength (G6). After 30 days immersion in distilled water at 37°C, the TBS was determined. Results: TBS results were higher for MBC than for SBC (P = 0.00012). The experimental groups were similar for SBC and the TBS was 27% of its cohesive strength. For P60, sandblasting significantly improved the TBS compared to other groups. With MBC, G4 and G5, the TBS was approximately 47% of its cohesive strength. Conclusion: Sandblasting (Al2O3) improves the repair-strength of MBC, whilst for the SBC all treatments succeed. MBC presents higher repair strength than SBC. [ABSTRACT FROM AUTHOR]

This study verified the influence of storage and compressive loads on the microtensile bond strength (µtbs) of an adhesive system when using the conventional technique or collagen removal treatment. Twenty bovine teeth were separated into four groups: G1) adhesive system Prime & Bond NT (PENT) in accordance with the manufacturer's instructions, G2) PBNT after deproteinization with 10% sodium hypochlorite (NaOC1), G3) PBNT in accordance with the manufacturer's instructions + 50,000 compressive cycles and G4) PBNT after deproteinization + 50,000 compressive cycles. After 24 hours, the teeth were sectioned and half of the specimens were stored in water (37°C) for further evaluation (after 60 days). The failure mode was evaluated by scanning electron microscopy (SEM). The bond strength values were separately submitted to two-way ANOVA for each period and the differences among groups were determined by Tukey's test (p=0.05). Comparisons between 24 hours and GO days were determined by multiple paired Student's f-tests (5%). The evaluation at 24 hours revealed that deproteinization did not affect µtbs for the non-cycled groups (G1 = 47.8 ± 4.7 and G2 = 52.4 ± 11.32). For the groups tested after the mechanical cycles, deproteinization produced higher µtbs (G3 = 32.7 ± 9.6 and G4 = 43.3 ± 16.7). At 60 days, deproteinization produced higher µtbs than the manufacturers' recommendations for the cycled and non-cycled groups (GI = 31.5 * 5.8; G2 = 48.8 ± 7.7; G3 = 17.1 ± 7.2 and G4 = 48.8 ± 12.2). In conclusion, the deproteinized groups were less susceptible to degradation than the groups restored with the conventional technique. [ABSTRACT FROM AUTHOR]

Purpose: To determine the degree of conversion (DC), physicochemical properties, and microshear bond strength (µSBS) of experimental self-adhesive resin cements (SARCs) to dentin and yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramic., Materials and Methods: Dual-curing cements were formulated with UDMA, HEMA, bis-GMA, and TEG-DMA as the organic matrix. 2MP (bis 2-(methacryloyloxy)-ethyl-phosphate) and GDMAP (1,3-glycerol dimethacrylate phosphate) were added to impart self-adhesive characteristics. A control group was formulated without self-etch methacrylates. Silanized particles were incorporated. Photoactivation was carried out using an LED light-curing unit (1200 mW/cm2) for 20 s. Infrared spectroscopy assessed the DC immediately and after 24 h. pH was analyzed in real time and recorded after 48 h. Water sorption (Wsp), water solubility (Wsl), and film thickness measurements followed ISO 4049. µSBS of the cements to dentin and Y-TZP was evaluated immediately and after 3 months of water storage. Y-TZP was also tested without a surface treatment and after tribochemical silica coating with subsequent application of a silane agent. The fractures patterns were classified as adhesive, cohesive, and mixed. Data were submitted to analyses of variance and Tukey's tests (α = 0.05)., Results: Control (91.7%) and 2MP (92.0%) groups generated the highest DC after 24 h. 2MP (pH = 3.6) showed the lowest pH followed by GDMAP (pH = 4.7) and control (pH = 6.4) after 48 h. The control cement exhibited lower Wsp (41.0 µg/mm3) and Wsl (4.3 µg/mm3) than the other groups. Film thickness was statistically similar (p = 0.266) for all cements. Control (27.0 MPa) and GDMAP (24.1 MPa) showed higher µSBS to dentin than 2MP (13.7 MPa) after water storage. Mixed fractures were predominant in dentin. For all cements, the µSBS to Y-TZP was < 3.0 MPa after water storage, independent of the surface treatment., Conclusion: The results of DC, pH, Wsp and Wsl were material dependent. Only the film thickness was statistically similar for all groups. The cement formulated with GDMAP maintained the bond strengths to dentin even after aging. However, none of the groups were able to generate satisfactory bond strength to Y-TZP, independent of the surface treatment.