Localized wear of compomer restorative materials

Purpose: To determine and compare the localized wear of six compomer restorative materials. Materials and Methods: Ten specimens of Dyract, Dyract AP, F2000, Compoglass F, Elan and Hytac were prepared in a custom fixture and polished. A pretest surface profile was generated using an MTS 3-D surface profilometer and the specimens were subjected to 400,000 cycles in a Leinfelder wear machine equipped with a conical stylus tip to simulate localized wear. A post-test profile was generated and the before and after profiles were fitted and analyzed using AnSur 3-D software. The total volume loss and depth of the wear facet on each specimen was calculated and statistical analysis was accomplished (ANOVA and Tukey's test). Results: Volume loss (mm³) was as follows: F2000, 0.027 ± 0.002; Hytac, 0.007 ± 0.023; Elan, 0.054 ± 0.013; Compoglass F, 0.135 ± 0.006; Dyract AP, 0.135 ± 0.023; Dyract, 0.185 ± 0.032. Maximum depth of the wear facets (μm) was as follows: F2000, 112.2 ± 10.2; Hytac, 132.8 ± 9.3; Elan, 144.3 ± 23.1; Compoglass F, 168.3 ± 13.0; Dyract AP, 194.0 ± 19.7; Dyract, 220.6 ± 15.8. There was not a difference (P> 0.05) in volumetric loss between F2000 and Hytac or between Hytac and Elan. The volume loss and maximum depth of the wear facets of F2000, Hytac and Elan was significantly less (P<0.05) than Compoglass F, Dyract AP and Dyract The results of this study indicate that there are significant differences in the in vitro wear rates of compomer materials.