Wear of Alumina Reinforced PMMA Using Different Amount of Silane

Objectives: To evaluate the effects of alumina filler silanized with different amount of silane coupling agent on wear resistance of alumina reinforced methacrylate denture base. Methods: Alumina filler, spherical in shape with diameter 23-35 µm, was silanized with 0, 0.1, 0.2 and 0.4 wt% of gamma-methacryloxypropyltrimethoxysilane (MPS). The 10 wt% of filler with 4 different amounts of silane was mixed with heat polymerizing polymethymethacrylate (PMMA, Triplex hot, Ivoclar Vivadent AG). Heat polymerizing PMMA without alumina reinforced was served as control. Fifty specimens, 10 x 10 x 2.5 mm, were prepared (n=10). The specimens were immersed in distilled water at 37^oC for 24 h prior to the test. The in-vitro 2-body wear-testing apparatus was used in this study. The micro grained aluminum oxide grit bur (Dura-White® Stones, Shofu) diameter 3 mm was used as the antagonist. The antagonist was rotated for 100,000 cycles at speed of 1000 rpm, accompanied with 15 N vertical loading on the specimen. The volume loss (mm³) of each specimen was measured using a profilometer (TalyScan 150, Leicester, UK) and analyzed by ANOVA and Tamhane; P<0.05. Results: The mean of volume loss and (SD) in mm³ of all groups were 0.16(0.02) in control group, 0.070 (0.01) in 0 wt% group, 0.038 (0.01) in 0.1 wt% group, 0.039 (0.01) in 0.2 wt% group, and 0.042 (0.01) in 0.4 wt% group. The statistic analysis showed that volume loss of the three silanized filler reinforced PMMA groups was significantly lower than the others with P< 0.05. Conclusions: Within the limitations of this study, it was concluded that the addition of 10 wt % of alumina filler silanized with 0.1, 0.2, and 0.4 wt % MPS into PMMA was able to increase wear resistance of alumina reinforced PMMA.