Capacidade de mascaramento de substratos escurecidos com uso de opacificadores e resina composta

Abstract

The aim of this study was to evaluate the masking ability of a combined application of opaquers and resin composite over discolored backgrounds - A3, A3.5, C2, C3, C4. The groups were divided according to the opaquer brand, number of opaquer coats (one or two) and thickness of the resin composite layer (0.5 or 1.0 mm). The color measurements were made by a reflection spectrophotometer (SP60, EX-Rite). The color difference between the opaquer + resin composite + background and a reference background was calculated using a CIEDE2000 formula. ANOVA and Tukey’s post hoc (p= 0.05) were used to analyze the ΔE00* mean values. A bivariate analysis was used to determine the association between dependent and independent variables. The masking ability was rated by the ΔE00* visual thresholds of acceptability and perceptibility (Excellent Match ≤0.8, Acceptable Match >0.8≤ 1.8, Moderately Unacceptable Mismatch >1.8≤3.6, Clearly Unacceptable Mismatch >3.6≤5.4, Extremely Unacceptable Mismatch >5.4). The mean ΔE00* values ranged from 0.5 to 5.52. Excellent match was observed in six combinations. Overall, the combination of one or two opaquer coats + 1.0-mm resin composite layer presented acceptable masking ability for most of the tested backgrounds. Masking ability was affected by the opaquer brand, the thickness of the resin composite layer and the background shades.