Effect of contemporary polishing systems on hardness and roughness of one-shaded dental composites

Abstract

One-shaded dental composites have gained importance in dental practices because they can match a tooth’s color in a short period of time. Polishing is an important step in dental treatments. Therefore, the aim of the present study is to evaluate the effects of contemporary polishing systems on the hardness and roughness of one-shaded dental composites. Three one-shaded dental composites (Omnichroma (OMN), Charisma Diamond One (CDO), and Vittra Unique APS (VUA)) were used to prepare composite specimens (n = 120). For each group besides the control one (n = 10), the specimens were randomly divided into three polishing systems: Sof-Lex Discs (SLD), Clearfil Twist Dia (CTD), and Optionestep (OSP). Microhardness measurements were performed using Vickers hardness. Surface roughness values were determined using a contact profilometer. The data were analyzed using two-way ANOVA and two-way robust ANOVA tests at a significance level of 0.05 for both results. One representative sample from each group was examined with scanning electron microscopy (SEM) and SEM- Energy Dispersive X-Ray Spectroscopy (EDX). The control group of VUA had the lowest hardness value, while the CDO polished with SLD had the highest hardness value. The control group of CDO had the highest roughness value, while the OMN polished by SLD had the lowest roughness value. All the polishing systems caused some micro-stratches or micro-grooves on the surface of one-shaded dental composites owing to the effect of abrasive particles in the polishing systems. Polishing systems were found to have an important effect on the hardness of the one-shaded dental composites. Two-step polishing may be used instead of four-step polishing systems to shorten dental treatments on one-shaded composites.