Color match of single-shade restorations after professional dental bleaching: An in vitro study

Restorative dentistry aims to reproduce natural tooth shades through resin composites that must be layered to obtain colors, opacities, and translucencies, and therefore, clinical success is operator skill dependent.

The purpose of this study is to evaluate the color shift of single-shade composite restorations before and after dental bleaching.

Eighty human extracted posterior teeth were restored with four single-shade composites (Omnichroma OM; Clearfil Majesty ES-2 Universal CL; Essentia Universal ES; Venus Diamond One VE) (n = 20 each). Standardized V class cavities were prepared on buccal side. VITA Easyshade V spectrophotometer was used to register VITA color and color coordinates 24 h before (T₀), 24 h after (T₁), and 1 week after (T₂) dental bleaching (Opalescence Boost PF 40%). Color differences (ΔE_ab) and (ΔWI_D) were calculated and subjected to statistical analysis.

Categorical variables were analyzed using Pearson Chi-square, and data from color coordinates were analyzed using one-way analysis of variance and Tukey's multiple comparison test with Bonferroni correction. Paired t-tests were performed to compare continuous measures between groups and treatment time.

Instrumental evaluations revealed statistically significant differences between materials (P < 0.05) with lower values for ES and VE samples followed by CL and OM at T₀ and T₁. At T₂, OM and CL ΔE_ab values decrease getting closer to ES and VE.

Single-shade composites seem to match with the surrounding bleached tooth.