Surface Roughness of Micro-hybrid Composite Using Various Polishing Systems

Objectives: Achieving the smoothest surface roughness of resin-based composites is a primary challenge for their clinical success. In particular, the roughness is known to positively enhance the bacterial adhesion. The aim of this study was to evaluate the effects of seven different polishing systems, from simplest to most complex, on the final roughness of a microhybrid composite.
Methods: Forty-two discs of a microhybrid composite (G-aenial Anterior, GC, Belgium) were made and randomly divided into seven groups (n=6). All the specimens were first roughened by silicon carbide papers (grid P120, P320, P600) prior to being polished by: CompoSystem discs (Komet, Germany), Sof-Lex discs (3M Espe, USA), Twist Dia wheels (Kuraray, Japan), 2-steps composite polishers (Komet, Germany), 1-step polisher Maximus (Kenda, Lichtenstein) and Enamel Plus Shiny kit (Micerium, Germany). The average surface roughness (Ra) was measured before and after polishing by a 3D optical microscope with white light interferometry (WLI). The obtained data were analyzed by a Kruskal-Wallis non parametrical test at a p=0.05 significance level.
Results: The surfaces polished by Maximus, Enamel Plus Shiny kit and Sof-Lex discs were significantly smoother (p<0.5) than surfaces polished by the silicon carbide paper P600 (respectively, Ra=0.12+/-0.03; 0.16+/-0.03; 0.22+/-0.08; 0.82+/-0.22). Maximus and Enamel Plus Shiny kit produced significantly smoother surfaces than the Twist Dia wheel system (Ra=0.36+/-0.02; p<0.5). The average surface roughness of samples polished by the CompoSystem discs and 2-steps polishers system were not statistically different (respectively, Ra=0.28+/-0.05; 0.21+/-0.01; p<0.5).
Conclusions: In our study, the microhybrid composite G-aenial Anterior was best polished respectively with the 1-step system Maximus, Enamel Plus Shiny kit and Sof-Lex discs. The roughest surfaces after polishing were obtained when using rubber wheels. Interestingly, the smoothest surfaces were equally obtained with the simplest and the most complex polishing systems tested.