HYDROLYTIC STABILITY OF SILANATED ZIRCONIA-SILICA-URETHANE DIMETHACRYLATE COMPOSITES

The effect of the method of silanation of zirconia-silica by 3-methacr yloxypropyltrimethoxysilane (MAPM) and 3-acryloxypropyltrimethoxysilan e (APM) on the diametral tensile and transverse strength of composites made from these silanated fillers and a urethane dimethacrylate was d etermined after 0-108 h of boiling in water. The water sorption of the se composites was also measured at times up to 108 h. Silanation with either silane significantly increased the tensile and transverse stren gths and decreased water sorption relative to comparable unsilanated c ontrols. Silanation with MAPM from ethanol solution at three times the minimum uniform coverage gave the best overall results, and the tensi le strength tests appeared to be most predictive of effectiveness of t he silane treatments.