Avaliação da rugosidade de superfície com o uso da perfilometria em diferentes regiões de overlays em dissilicato de lítio, após três tratamentos: glaze, acabamento e polimento

Abstract

This aim in vitro study to evaluate the surface roughness of non-flat specimens after using a finishing and polishing system using contact profilometry. Using the computer-aided design (CAD) and computer-aided manufacturing (CAM) system, milled overlays were manufactured in lithium disilicate (IPS e.max CAD, Ivoclar Vivadent AG, Schaan, Liechtenstein). For each sample (N=5), three specific regions were selected: an external smooth slope (VE), an internal grinding slope (VI), and a proximal area between the marginal crest and the proximal fossa (Niche), and three different treatments, namely: glazing (G), finishing (A), and polishing (P). The finishing system used was fine and ultrafine diamond burs, and the polishing system used was Optragloss-type rubbers (Ivoclar Vivadent AG, Schaan, Liechtenstein). Through contact profilometry, it was possible to generate a quantitative assessment through roughness profiles and a qualitative assessment through three-dimensional (3D) images. Data normality was assessed using the Shapiro-Wilk test, with all groups showing a normal distribution and a significance level of 5% (p > 0.05). All collected data were subjected to a two-factor analysis of variance with repeated measures and Tukey's post hoc test. The results revealed that the polishing was efficient and that there was a statistically significant difference between the finish and polishing in VE and VI and between the glaze and the finish in VE. However, there was no statistically significant difference between the glaze and the finish. Furthermore, these results were confirmed by 3D images. It is concluded that the VE region presented the best performance for both laboratory polishing (G) and intraoral polishing (P), with values close to the clinically acceptable limit in the literature. While the N region presented Ra values that were statistically equal to Ra in all protocols evaluated, suggesting that this region, due to the complexity of its topography, requires different finishing and polishing methods.