Instrumental Colorimetric Evaluation of Combined Enamel and Dentin Composite Resins Compared to the Vita Classic Shade Guide

Accurate color determination in dental restorations is crucial for achieving aesthetically pleasing and functional results. Traditionally, color selection has been performed using visual methods, which are subject to observer variability and factors such as lighting and experience. However, the use of instrumental technologies like spectrophotometry has allowed for greater objectivity and reproducibility in color measurement. This study aims to evaluate the accuracy of color determination in composite resin restorations using spectrophotometry, comparing the results obtained with the Vita Classic shade guide. A total of 120 samples were prepared using 4 types of composite resins and 3 enamel/dentin combinations (A2, A3, and A3.5), with 0.7 mm thickness for enamel and 1.3 mm for dentin, achieving a final thickness of 2 mm. Color measurements were taken with a Vita™ Easyshade® spectrophotometer, and the results were expressed in terms of ΔE using the CIE Lab* formula. Normality (Shapiro-Wilk) and homoscedasticity (Levene) tests were applied, and one-way ANOVA was used to assess differences between resin brands and shades. The results showed that, although no statistically significant differences were found in the A2 and A3 shades between brands, the A3.5 shade exhibited significant variations, with Filtek Z350 XT® 3M Espe Solventum being the resin that showed color values closest to the ideal.