Staining power of natural and artificial dyes after at-home dental bleaching

Abstract

Introduction: Bleached enamel surfaces may undergo changes and retain more dye, which is a reason to recommend the reduction/suspension of foods with dyes during dental bleaching. Aim: Evaluate the effects of the action of natural and artificial dyes on the bleached enamel of extracted human teeth. Materials and methods: Fifty human premolars were used, which were distributed in 5 groups (n = 10) according to the following staining solutions: GW (distilled water); GB (beet); Gca (caramel); GC (carmine); and GR (red 40). After the removal of the root and pulp section, the teeth were embedded in acrylic resin blocks, stored in artificial saliva, and kept at 37°C. At-home bleaching was performed using 16% carbamide peroxide (CP) for 3 hours daily for 3 weeks. After each daily session of bleaching, the specimens were exposed to the dye solution twice a day for 5 min; one of these exposures was performed immediately after bleaching. The color was recorded using a spectrophotometer according to the CIE Lab system (ΔE) for the following periods: baseline, during bleaching (after 1st, 2nd, and 3rd week) and post-bleaching (after 1 week and 1 month). The color was evaluated by two-way analysis of variance and Tukey's test (α=0.05). Results: There was effective dental bleaching for all groups: GW (18.5 ± 6.1), GB (19.9 ± 4.4), Gca (18.9 ± 6.1), GC (20.2 ± 4.6), and GR (19.3 ± 4.2), p < 0.01. No color rebound was observed after 1 week and 1 month (p > 0.05). Conclusion: The exposure to beet, carmine, caramel, and red 40 dyes did not interfere with the effectiveness of dental bleaching using 16% CP. Clinical significance: Dyes consumption during bleaching did not affect the effectiveness of dental bleaching.