Wear and Thermal Stress Resistance of Hydrophobic Silanized Resin Composite.

Objectives: This study was carried out to evaluate the thermal stress resistance of resin composites containing the fillers treated with 3-(3-methoxy-4- methacryloyloxyphenyl)propyltrimethoxysilane (p-MBS) having a phenyl group as a hydrophobic group.
Methods: Three experimental light-cure hybrid resin composites were formulated which contain 85 wt% of fillers treated with p-MBS, mixture of 3-methacryloyloxypropyl- trimethoxysilane (3-MPS) and fluoroalkylsilane (4F) or 3-MPS alone. One commercial composite, Clearfil AP-X (Kuraray Medical Co.) was also used. The prepared specimens were stored in room temperature for one day before being finally thermal stressed for 30,000 cycles. Then the specimens were subjected to the two-body-wear test (10,000 cycles, n=10) and to the tensile test. The collected data were analyzed statistically using the one-way ANOVA and Tukey’s multiple comparison test as the post-hoc test.
Results: The amounts of composite wear containing fillers treated with p-MBS and 4F/3-MPS was significantly lower (p<0.05) when compared with the composites containing fillers modified with 3-MPS and Clearfil AP-X. The tensile strengths of the composites containing filler treated with p-MBS or 4F/3-MPS was significantly higher compared with the 3-MPS alone or Clearfil AP-X after thermal cycling test. There were no significant decreases of the tensile strengths for the p-MBS or 4F/3-MPS composite after the thermal cycling test.
Conclusions: The resin composites containing fillers treated with the novel hydrophobic silane showed superior wear and thermal stress resistance. The reason might be that the coupling layers of this silane may have a high affinity with the base resin and improved hydrophobic properties, too. This study was supported by grant (#15592077, 16390548, 16791158, and 16791166) from the Ministry of Education, Science, Sports and Culture of Japan.