IADR Abstract Archives
Resin Cements Containing Thio-Urethane Can Strengthen Ceramic
Objectives: The aim of this study was to evaluate the possible strengthening effect when resin cement containing synthesized thio-urethane (TU) additives was applied to a lithium disilicate glass ceramic.
Methods: Two types of thio-urethanes were synthesized (aromatic or aliphatic backbones). Those were added at 0 (control) or 20 wt% to a BisGMA/UDMA/TEGDMA (50/30/20 mass-ratio) resin, containing 0.2 wt% of dl-camphoroquinone and 0.6 wt% of a tertiary-amine. RelyX Ultimate (RU) was used as the commercial control. Ninety ceramic discs (Empress 2, Ivoclar-Vivadent, 12 mm diameter, 0.6 mm thick) were made according to manufacturer’s instructions and were left. untreated (positive control), acid-etched and silanized (negative control) or acid-etched, silanized, and coated with the resin cements. Biaxial flexural strength (σbf) was tested using a ball-on-ring setup (1.0 mm/min), with the treated surface on the bottom, and calculated at two z-axial positions: z = 0 position (ceramic surface at the bonded interface) and z = -t2 position (luting agent surface resting on ring). Data were analyzed with ANOVA/Tukey’s test (α=0.05).
Results: Results are shown in the table. In general, the σbf of all groups containing resin cements, regardless of the type, were significantly higher than the positive/negative controls. Both TU-modified cements showed statistically greater σbf at either z position compared to the experimental control. The TU modification was able to increase the σbf to statistically similar values to the commercial control, whose composition is vastly optimized by the manufacturer. Allied to the previously described reduction in stress provided by these materials, this might help improve the longevity of the cemented interface.
Conclusions: All resin cements were able to strengthen the ceramic, with the non-optimized TU-modified material presenting similar results to the fully formulated commercial material.
Methods: Two types of thio-urethanes were synthesized (aromatic or aliphatic backbones). Those were added at 0 (control) or 20 wt% to a BisGMA/UDMA/TEGDMA (50/30/20 mass-ratio) resin, containing 0.2 wt% of dl-camphoroquinone and 0.6 wt% of a tertiary-amine. RelyX Ultimate (RU) was used as the commercial control. Ninety ceramic discs (Empress 2, Ivoclar-Vivadent, 12 mm diameter, 0.6 mm thick) were made according to manufacturer’s instructions and were left. untreated (positive control), acid-etched and silanized (negative control) or acid-etched, silanized, and coated with the resin cements. Biaxial flexural strength (σbf) was tested using a ball-on-ring setup (1.0 mm/min), with the treated surface on the bottom, and calculated at two z-axial positions: z = 0 position (ceramic surface at the bonded interface) and z = -t2 position (luting agent surface resting on ring). Data were analyzed with ANOVA/Tukey’s test (α=0.05).
Results: Results are shown in the table. In general, the σbf of all groups containing resin cements, regardless of the type, were significantly higher than the positive/negative controls. Both TU-modified cements showed statistically greater σbf at either z position compared to the experimental control. The TU modification was able to increase the σbf to statistically similar values to the commercial control, whose composition is vastly optimized by the manufacturer. Allied to the previously described reduction in stress provided by these materials, this might help improve the longevity of the cemented interface.
Conclusions: All resin cements were able to strengthen the ceramic, with the non-optimized TU-modified material presenting similar results to the fully formulated commercial material.
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