BRUXING-TYPE DENTAL WEAR SIMULATOR FOR RANKING OF DENTAL RESTORATIVE MATERIALS

An instrumented dental wear test simulator was developed to simulate j aw movement in the chewing process between two molar teeth. It simulat ed the natural impact with sliding masticatory action, known as bruxin g (defined as the gnashing, grinding, or clenching of teeth) type of w ear, in order to simulate a worst-case dental wear scenario. III vitro wear testing of dental restorative materials was performed. Impact an d sliding wear were simulated on the machine, with water as the lubric ant, on three metal alloys (Tytin, Valiant Ph.D., Galley) and three co mposite resins (Silux Plus, Z100, P50), The impact force for each mach ine cycle was brought closer to the maximum natural masticatory forces by the use of a shock absorbing layer. To replicate the natural masti catory action, the specimens had a surface profile with the shape of a conical depression, Ranking of the materials' performance on the wear test simulator was seen to be consistent with published clinical rank ing, Metal alloys showed greater wear resistance than composite resins , Among the different metal alloys, those with lower hardness and comp ressive strengths exhibited greater wear. Composite resins with large filler particles wore worse than those with small filler particles, Re sults were compared with previous work on impact with sliding on a fla t surface without a cushioning layer, It was concluded that the magnit ude of the impact force and the angle of approach during impact with s liding wear are important parameters in the in vitro wear ranking of d ental restorative materials. (C) 1998 John Wiley & Sons, Inc.