Hydrolytic stability of silanated zirconia-silica-urethane dimethacrylate composites

The effect of the method of silanation of zirconia-silica by 3-methacryloxypropyltrimethoxysilane (MAPM) and 3-acryloxypropyltrimethoxysilane (APM) on the diametral tensile and transverse strength of composites made from these silanated fillers and a urethane dimethacrylate was determined after 0-108 h of boiling in water. The water sorption of these composites was also measured at times up to 108 h. Silanation with either silane significantly increased the tensile and transverse strengths and decreased water sorption relative to comparable unsilanated controls. Silanation with MAPM from ethanol solution at three times the minimum uniform coverage gave the best overall results, and the tensile strength tests appeared to be most predictive of effectiveness of the silane treatments.