Surface Roughness of Commercial Composites after Different Polishing Protocols: An Analysis with Atomic Force Microscopy

BACKGROUND AND AIMS: Polishing may increase the surface roughness of composites, with a possible effect on bacterial growth and material properties. This preliminary in vitro study evaluates the effect of three different polishing systems (PoGo polishers, Enhance, Venus Supra) on six direct resin composites (Gradia Direct, Venus, Venus Diamond, Enamel Plus HFO, Tetric Evoceram, Filtek Supreme XT). MATERIALS AND METHODS: For each composite, 12 square specimens were prepared: 9 specimens were polished, three for each different method, while three specimens were used as controls. Surface roughness was determined with AFM by measuring Root Mean Square (RMS) of average height. RESULTS: PoGo polisher determined a significantly rougher surface, versus controls, in 5 out of 6 composites evaluated. Some significant differences from unpolished controls were observed also for Enhance polishing. Polishing with Venus Supra did not result in any significant difference in surface roughness versus controls. No differences were observed between different polishing systems. CONCLUSIONS: These preliminary results suggest that Venus Supra polishing system could determine a smoother composite surface if compared to the other polishing systems tested. On this basis, we are conducting an in vivo study to evaluate bacterial colonization on some combinations of composites and polishing protocols.