Effect of polishing on surface roughness and morphology of composites

Method: A total of 240 composite dics, 30 from each type, 5mm in diameter and 2mm thick were polymerized under Mylar matrix according to the manufacturer’s instructions. Each composite group was randomly divided into three subgroups (n=10). 1- Mylar matrix (control); 2- wet polished with Enhance/PoGo; and 3- wet polished with Venus Supra polishing systems, after pre-roughening the Mylar surfaces with 320 grit SIC paper. The quantitative evaluation of the surface roughness was performed with a profilometer (Perthometer Mahr), while the qualitative examinations were done using SEM and AFM. Data were analyzed using one-way ANOVA followed by Tukey's test, two-way ANOVA, and post hoc Bonferroni test at a significance level of p<0.05. 

Result: Surface roughness was significantly influenced by the composite (p<0.0001) and the polishing system (p<0.0001), and the interaction between them was statistically significant (p<0.0001). In each composite group, the smoothest surfaces were obtained under the Mylar matrix (control), whereas both polishing systems created significantly rougher surfaces than their corresponding control groups (p<0.05). For both polishing systems, Estelite Omega and Estelite ∑ Quick presented the lowest surface roughness, while Clearfil Majesty Posterior and Beautifil II presented the highest. Except for G-aenial (p=0.332), Charisma Diamond (p=0.616), and Beautifil II (p=0.411), the differences in surface roughness between the Enhance/PoGo and Venus Supra polishing systems in each composite group were significant, showing smoother surfaces for Enhance/PoGo (p<0.05). 

Conclusion: The effect of polishing systems on surface roughness is dependent upon both the polishing system and the composite resin.