Abrasive wear testing of dental restorative materials

A tribometer (model ISC-200PC) was modified to form a pin-on-disk type of wear test apparatus. A dental restorative material specimen was used as the pin and a diamond grinding wheel as the abrasive counterface. Both normal and friction forces were recorded during the course of the test. The volumetric wear rate was calculated from the change of length and cross-sectional area of the specimen. The failure mode on the worn surface was analyzed using scanning electron microscopy (SEM) photographs. The specific wear rates and friction coefficients of three commercial dental restorative products, Z-100 (3M), Renamel (Cosmedent) and Clearfil AP-X (Kuraray), were compared. A parametric study of the effects of filler volume fraction and particle size on the wear resistance of a glass bead filled BisGMA/TEGDMA resin showed that relative wear rate increased with the volume fraction and decreased with average particle diameter of the glass beads. The behavior was explained in terms of matrix failure mode, particle pull-out and inter-particle spacing. (C) 1998 Elsevier Science S.A. All rights reserved.