Chromatic influence of value resin composites

The current study evaluated the chromatic influence of high, medium and low value composites on a dentin composite substrate (A2 shade) using spectrophotometric analysis. The specimens were divided into the following four groups: a) control (CG), entirely composed of dentin composite (n = 5); b) high value (GHV), dentin composite and high value composite (n = 20); c) medium value (GMV), dentin composite and medium value composite (n = 20) and d) low value (GLV), dentin composite and low value composite (n = 20). The dentin composite was 2.0 mm thick and the value composite was added in four different thicknesses, dividing the groups into four subgroups: S1 = 1.0 mm, S2 = 0.8 mm, S3 = 0.6 mm and S4 = 0.4 mm. The results were determined using the CIELAB system and differences in brightness of the specimens were analyzed using two-way ANOVA. Significant differences were found between different value resin composites, thicknesses and interactions, as revealed by the Tukey's test (HSD). Adding value composite produced lower brightness, and a gray shade was observed, compared to the control, regardless of the value or thickness of the primary composite. Eleven of the 12 subgroups presented clinically unacceptable chromatic changes, except when the 0.4 mm thickness of high value composite was used.