Translucidez e valor: análise do comportamento das propriedades ópticas em resinas compostas estéticas

Abstract

This study aimed to evaluate the translucency and value with different combinations of enamel , dentin and body of each composite regarding a standard thickness (1,5mm). Three different resin composites commercially available with a standard shade (A1), IPS Empress Direct, Charisma Diamond and Filtek Z350 XT were evaluated. A stainless steel matrix was used to prepare ninety disc-shaped specimens with 11mm diameter and 1,5mm thickness. The specimens were randomly allocated in 18 groups (n=5) according to different combinations of enamel , dentin and body presented in each resin composite evaluated. After light curing, specimens were stored in deionized water at 37º C for 24h. Three consecutive readings were performed according to the CIE L*a*b* color scale relative to the standard illuminant D65 on reflection spectrophotometer (SP60 - EX-Rite). The optical properties of translucency and value were measured by the parameters translucency (TP) and lightness in white background (L*w) and black background (L*b), respectively. The mean TP, L*w and L*b were analyzed by ANOVA (General Linear Models) and Tukey s post hoc tests (α =0.05). Scatter plots together with Spearman´s correlation coefficient were used to assess the relationship between TP and L*w and TP and L*b values. The groups had statistical significant different values (p=0.000). The resin composite Empress Direct when only a layer of enamel were employed presented the highest TP value, whereas the resin composite Filtek Z350 XT with a single layer of dentin presented the lowest TP value. A negative and strong correlation between TP and L*b and a positive and weak correlation between TP and L*w were observed. Optical properties as translucency and value rely on the material used. In general, there was statistical difference between the groups for TP and L*