effect of chemical and mechanical degradation on surface roughness, topography, gloss, and polish retention of three composites polished with five polishing systems

objective: finishing and polishing (f/p) of composites is a fundamental step influencing the clinical service of restorations. the aim of this study was to evaluate the effect of different f/p systems on surface roughness, gloss, and polish retention of composite resins. materials and methods: one-hundred and five disc-shaped specimens (4×4 mm) were made from nanofilled, microhybrid, and microfilled composites (n=35). the specimens were divided into five subgroups (n=7) for f/p with sof-lex (4-step), shofu (4-step), cosmedent (3-step), diacomp composite-pro (2-step), and opti1step systems. the surface roughness values (ra and rz) were measured before and after ph-cycling and simulated toothbrushing. surface topography was assessed by using a scanning electron microscope (sem) at three magnifications. for assessment of surface gloss, 45 rectangular specimens (10×8×2 mm) were fabricated from three composites (n=15) and randomly allocated to five subgroups (n=3). surface gloss was measured before and after aging. the mean values were calculated and analyzed by two-way anova, tukey, and t-test. level of significance was set at 0.05. results: the composite type had no significant effect on surface roughness (p 0.05); however, the type of f/p system significantly affected it (p 0.05). the ph-cycling and simulated toothbrushing had no significant effect on gloss or polish retention of the three composites (p 0.05). conclusion: type of f/p system had a greater effect on surface roughness and gloss of composite resins than the type of composite.