Visual and Instrumental Color Match Evaluation of Single Shade Composites before and after Bleaching Procedures: A Pilot Study

Background: One of the major challenges in restorative dentistry is to obtain an adequate color match between composite restorations and the surrounding tooth. This match depends on several chromatic variables related to the composite itself but also to the teeth. Bleaching procedures are not to be able to modify the shade of composite restorations to a lighter color as it does on natural teeth. Objective: The objective of this study is to evaluate the visual and instrumental color match of two single-shade resin-based composites in human-extracted teeth before and after bleaching treatment. Methods: Six extracted human posterior sound teeth were used. Round-shaped V-class cavities (2x2x4mm) were prepared buccally 2mm away from the CEJ. Two single-shade resin composites (OM-Omnichroma and VE-Venus Diamond One) were used for the restorations. Tooth color was measured using an intraoral spectrophotometer. Visual analysis was carried out by 16 calibrated observers, and the differences were graded from 0 (excellent match) to 4 (huge mismatch). Teeth were then bleached using 40% H2O2 (Opalescence Boost PF, Ultradent), and visual and instrumental evaluations were performed after 24 hours. Results: Before bleaching, visual analysis showed a mean value of 0.16 for OM and 0.24 for VE. After bleaching, the color match showed a mean value of 0.14 for OM and 0.22 for VE. Regarding the instrumental analysis, each restoration matched the tooth VITA scale grade before bleaching and followed the natural tooth VITA scale grade after bleaching procedures. Conclusion: Within the limits of this pilot study, both composites seem to have excellent color-match properties with the surrounding tooth structure.