Comparative wear ranking of dental restoratives with the BIOMAT wear simulator

Fundamental in vitro wear tests are important for the study of wear mechanisms, provision of data during material development and screening of materials prior to clinical trials. The aim of this project was to compare the wear of six dental restoratives using the BIOMAT wear simulator which was developed to simulate jaw movements and stresses generated in the occlusal contact areas during the chewing process. The correlation of wear to hardness of the restoratives was also assessed. Wear ranking from the least to the most volumetric wear was as follows: high copper unicompositional alloy, Tytin (T) < high copper admixed alloy, Valiant PhD (V) < microfilled composite resin, Silux Plus (S) < gallium alloy, Galloy (G) < heavily filled composite resin, Z100 (Z) < hybrid composite resin, P50 (P). The high copper amalgam alloys had significantly greater wear resistance when compared with all the composite resins. The gallium alloy, microfilled and heavily filled composite resins also exhibited significantly less wear than the hybrid resin. Wear ranking with the BIOMAT simulator was similar to that obtained in vivo. Ranking from the hardest to softest material: high copper unicompositional alloy, T < gallium alloy, G < high copper admixed alloy, V < hybrid composite resin, P < heavily filled composite resin, Z < microfilled 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.