Enamel Susceptibility to Coffee and Red Wine Staining at Different Intervals Elapsed from Bleaching: A Photoreflectance Spectrophotometry Analysis

Abstract

Objective: This study aimed to investigate bleached enamel susceptibility to coffee and red-wine staining at different time periods after bleaching. Background data: Although hydrogen peroxide is effective for dental bleaching, little is known regarding color stability immediately after bleaching. Materials and Methods: Fifty-four standardized bovine enamel slabs were obtained and assigned to the following treatments (n = 9): (CO) control: sound enamel surface submitted only to bleaching with 35% hydrogen peroxide (HP); (C30') enamel submitted to HP and coffee immersion at 30 min after bleaching; (C150') enamel submitted to HP and coffee immersion at 150 min after bleaching; (W30') enamel submitted to HP and red-wine immersion at 30 min after bleaching; and (W150') enamel submitted to HP and red-wine immersion at 150 min after bleaching. The color of treated enamel was determined by means of photoreflectance spectroscopy at baseline (T0) and after the described treatments (T(f)), and data were statistically analyzed with ANOVA and Tukey tests (p < 0.05). Results: No differences were observed between the exposure times of 30 and 150 min after bleaching for both beverages (p > 0.05). Although coffee did not stain the surface, red wine significantly darkened previously bleached enamel (p < 0.05). Conclusion: Bleached enamel was susceptible to red-wine staining at both 30 and 150 min after bleaching procedures, whereas coffee did not interfere with the bleaching process.