In vitro evaluation of OCA wear resistance of posterior composites

Objectives. Posterior composites undergo generalized (CFA) as well as localized (OCA) wear. The latter is caused by the contact of an antagonist cusp on the surface of the restoration. The purpose of this paper was to create OCA wear by means of a three-bodied wear device and also to develop a simple but reliable method for calculating loss of material in occlusal contact areas. Methods. After repeated cycles of loading, the OCA wear loss was measured with a profilometer, and the worn surfaces were observed through scanning electron micrography. Results. The results of this study have demonstrated significant differences in wear values among materials. These findings suggest that the difference in wear characteristics is derived from the mechanism by which the filler particle is bonded to the resin matrix. Significance. If OCA wear is of sufficient magnitude, it can cause appreciable changes in functional occlusion. Thus, knowing the OCA wear resistance of various composites is a prerequisite for developing a new composite with improved longevity and better clinical performance.