Impact of simulated brushing and abrasiveness of toothpaste on translucency, roughness and surface gloss of glass ceramics and tooth enamel

Abstract

This study aims to evaluate the effect of toothpaste abrasiveness on the surface roughness and gloss of glass-ceramics compared to dental enamel. The study will consist of a 3 x 4 factorial design (n=15), with the factor substrate in 3 levels: Ceramics leucite-reinforced glass-ceramic (LEU); ceramic lithium disilicate - reinforced glass ceramic (DL); and natural enamel (ESM); and the factor toothpaste abrasiveness at four levels: low with RDA equal to 7 (B); medium = 36 (M); coarse = 83 (A); and extra-coarse = 175 (XA). For this, LEU, DL and ESM discs (n=15) will be made (6 mm diameter, 2 mm thickness). The specimens will be polished with P1200, P2400 and P4000 grit silicon carbide sandpaper for 30s, 60s and 120s, respectively. A total of 100,000 brushing strokes will be performed by an automatic brushing machine with slurry containing toothpaste and deionized water in a 1:3 ratio. The Gloss (Gloss Unit - GU) and surface roughness (Ra - µm) will be evaluated before and after brushing simulation. Additional analyzes such as microhardness and scanning electron microscopy will also be performed. The mean and standard deviation will be calculated. Inferential statistics will consist of normality and homoscedasticity tests and, from these, the appropriate statistics will be determined. All with a 5% significance level. (AU)