Surface roughness and wear resistance of ormocer- versus methacrylate-based single-shade resin composites after simulated tooth brushing

To evaluate and compare the surface roughness and wear resistance of ormocer-based and methacrylate-based single-shade resin composites after simulated tooth brushing. Two single-shade composites; an ormocer-based composite (Admira Fusion X-tra, Voco) and a methacrylate-based composite (Omnichroma, Tokuyama), were used in this study. From each material, 20 disc-shaped specimens (3-mm thickness, 5-mm diameter) were prepared (n = 20). Specimens were subjected to 100,000 cycles of tooth brushing with a Colgate Max Fresh dentifrice (Colgate-Palmolive). The surface roughness was assessed before and after tooth brushing, and the changes in weight were determined after tooth brushing. Additional two specimens from each composite underwent scanning electron microscope (SEM) imaging. Paired and unpaired Student’s t-tests were used for statistical analysis (p < 0.05). Surface roughness of both tested composites increased significantly after brushing (p = 0.002 for ormocer-based composite and p = 0.006 for methacrylate-based composite). However, there was no statistically significant difference among the two tested composites regarding surface roughness before brushing (p = 0.928) or after brushing (p = 0.696). The weights of both tested composites decreased significantly after brushing (p = 0.001), and the amount of methacrylate-based composite wear was significantly higher than that of the ormocer-based composite (p < 0.001). After simulated tooth brushing, both tested composites (ormocer-based and methacrylate-based) became rougher, whereas the ormocer-based composite exhibited greater wear resistance than did the methacrylate-based composite.