The effect of contemporary finishing and polishing systems on the surface roughness of bulk fill resin composite and nanocomposites

Objective To evaluate the effects of various finishing and polishing (F/P) systems regarding the surface roughness (R-a) value of two nanocomposites and a bulk fill resin composite. Methods and Materials Three resin composites (Filtek Z550, Filtek Ultimate Body, Filtek Bulk Fill Posterior) were tested. Forty disk-shaped specimens of each material were cured under Mylar strip and then randomly divided into four subgroups according to the F/P method (n = 10): Control, Sof-Lex Spiral Wheels, Astropol, and Clearfil Twist Dia. R-a values was measured and the surfaces were examined under scanning electron microscope. The data were analyzed by generalized linear models (p < 0.05). Results The Filtek Bulk Fill Posterior had the highest R-a value while Filtek Ultimate Body was the resin composite with the lowest roughness (p < 0.05). Considering the average R-a values after polishing, while the lowest R-a in all groups was obtained with the control group, the Clearfil Twist Dia showed similar R-a to the control group (p > 0.05). The samples polished with Sof-Lex Spiral Wheels had the highest R-a (p < 0.05). Conclusions In addition to the resin composite type, the F/P technique greatly affected the R-a value of resin composite. The nanocomposites exhibited with the lowest R-a compared to the bulk fill resin composite after F/P. It was observed that the diamond containing-polishing system created smoother surfaces than the aluminum oxide containing- and silicon carbide containing-polishing systems. Clinical Significance In terms of R-a, the nanocomposites exhibited better performance than the bulk fill resin composites. Nowadays, newly developed polishing systems containing diamonds can be successful at a comparable level to existing polishing systems. For this reason, these systems are preferable for polishing both nanocomposites and bulk fill resin composites.