Assessment of the Effect of Finishing and Polishing and In-Office Bleaching on Surface Roughness of Commercially Available Resin Composites: An In-Vitro Study

Abstract

Aim:The aim of the current study was to evaluate the effect of finishing and polishing and an in-office bleaching gel on the surface roughness of single-shade (Omnichroma) and group-shade (Estelite Alpha) resin composites. Methodology: A total of ten composite disc-shaped specimens; five specimens for each material were prepared using Teflon mold (1-mm thick and 8-mm diameter). The resin composites were cured against mylar strips to produce flat smooth surface of the tested specimens. Then each disk was finished and polished using multi-step finishing and polishing system (Astropol, Ivoclar Vivadent). Each specimen was bleached using an in-office bleaching system two times in a row using 38% hydrogen peroxide (H2O2). The average surface roughness (Ra, in μm) of the specimens was measured using non-contact optical profilometry at baseline, after finishing and polishing, and after bleaching procedure. Intergroup comparison was performed using independent t-test, while intragroup comparison was performed using one-way ANOVA followed by Tukey post-hoc. Results: Comparison between both materials has revealed statistically significant difference at baseline (P = 0.0086), with Estelite Alpha showing higher surface roughness. However, after polishing and bleaching there was no statistically significant difference between both materials (P = 0.5796 and P = 0.3010) respectively. Conclusion: The surface roughness of resin composites is material dependent. Omnichroma demonstrated lower initial Ra value than Estelite Alpha. However, Omnichroma showed significant increase in surface roughness following finishing and polishing, unlike Estelite Alpha. Bleaching with 38% H2O2 showed no effect on the surface roughness of both materials.