Factors effecting dental composite wear in vitro.

The wear of posterior dental composite restorations takes place through a complex combination of wear mechanisms. To isolate and measure the contribution of the different tribological phenomena in a controlled manner, an oral wear simulator was employed. Results previously reported demonstrated the simulator's ability to form strong correlations with clinical results for both abrasion and attrition wear. These results were generated with the device configured to mimic masticatory dynamics, specifically employing a human enamel stylus, physiologic load levels, and a foodlike slurry for a third body. In this study the slurry was replaced with water to examine the role of the third body in producing abrasion. The third body was found to reduce wear for most materials. In a separate test the enamel stylus tip was replaced with steatite, a semiporous ceramic with wear characteristics similar to enamel when opposing dental composite. The use of a steatite antagonist increased abrasion for the larger particle filled materials. The adhesive wear mechanism was found to be a contributing factor in dental composite wear.