Comparative wear ranking of dental restoratives with the BIOMAT wear simulator

Fundamental in vitro wear tests are important for the study of wear mechani sms, provision of data during material development and screening of materia ls prior to clinical trials. The aim of this project was to compare the wea r of six dental restoratives using the BIOMAT wear simulator which was deve loped to simulate jaw movements and stresses generated in the occlusal cont act areas during the chewing process. The correlation of wear to hardness o f the restoratives was also assessed. Wear ranking from the least to the mo st volumetric wear was as follows: high copper unicompositional alloy, Tyti n(R) (T) < high copper admired alloy, Valiant PhD(R) (V)< microfilled compo site resin, Silux plus(R) (S) < gallium alloy, Galloy(R) (G) < heavily fill ed composite resin, Z100(R) (Z) < hybrid composite resin, P50(R) (P). The h igh copper amalgam alloys had significantly greater wear resistance when co mpared with all the composite resins. The gallium alloy, microfilled and he avily filled composite resins also exhibited significantly less wear than t he hybrid resin. Wear ranking with the BIOMAT simulator was similar to that obtained in vivo. Ranking from the hardest to softest material: high coppe r unicompositional alloy, T < gallium alloy, G < high copper admired alloy, V < hybrid composite resin, P < heavily filled composite resin, Z < microf illed composite resin, S. The amalgam alloys were significantly harder than the heavily filled and microfilled composite resins. There was no apparent correlation between wear performance and material hardness.