Comparative wear ranking of dental restoratives with the BIOMAT wear simulator. Part II. An SEM evaluation

The qualitative wear of amalgam alloys and composite resins opposing cast chromium alloys after impact-sliding wear simulation with the BIOMAT wear simulator was assessed. An impact stress of 28 MPa was adopted to allow for stresses generated during parafunctional activities. The worn specimens were examined using SEM at both impact sites and region of sliding wear. For amalgam alloys, ranking from the smoothest to the roughest surface under SEM observation was as follows: unicompositional alloy>admixed alloy>gallium alloy. For composite resins the ranking was: microfilled composite>small particle composite>hybrid composite. The qualitative SEM assessment results were consistent with our earlier volumetric wear results and supports the hypothesis that surface microstructure affects wear. Composite selection for teeth opposing cast chrome prostheses should be done with caution and knowledge of the composition of the material as three-body wear may occur.