THE EFFECT OF DIFFERENT POLISHING METHODS ON THE SURFACE ROUGHNESS OF RESIN COMPOSITES (AN IN-VITRO STUDY)

Abstract

Objective: To evaluate the effect of one-step, two-step, and multi-step polishing systems on the surface roughness of nanofilled and suprananofilled resin composite materials. Materials and Methods: A total of 56 resin composite discs were prepared (divided into 2 main groups of 28 discs each, as nanofilled and suprananofilled resin composite groups, using split Teflon mold and cured against Mylar celluloid strip. Except for control group, samples were ground with wet 600-grit silicon carbide paper, and then subdivided into 3 groups (n = 7) in each main group, as multi-step, two-step, and one-step polishing systems. Each polishing protocol was done according to manufacturer’s instructions using a kitchen scale to maintain pressure of each stroke approximately 30-40 gm. Scanning electron microscope was used to scan all samples, and the images were subjected to Gwyddion 2.56, (An SPM data visualization and analysis tool supported by the Czech Metrology Institute, 2020) to attain surface roughness average data, which were statistically analysed by two-way ANOVA followed by Tukey’s post hoc test. Results: The suprananofill groups as well as the one-step polisher groups had the least statistically significant surface roughness average values (p<0.001). Whereas the multi-step polisher groups had the highest statistically significant surface roughness average values followed by the two-step polisher, then the control groups (p<0.001). Conclusion: The one-step polishing system produces the smoothest surface, even smoother than setting against matrices, whereas polishing pastes produces the roughest surface. The suprananofill resin composite can obtain a smoother surface than the nanofill resin composite. KEYWORDS: Polishing, Surface roughness, nanofilled composite, Suprananofill composite, Omnichroma.