Clareamento caseiro com géis de peróxido de carbamida com concentrações inferiores à 10%: eficácia clareadora e permeabilidade

Abstract

Objectives: To evaluate the bleaching efficacy and permeability of hydrogen peroxide (HP) in the pulp chamber of teeth bleached with lower concentrations of carbamide peroxide gel (CP). Material and Methods: Bleaching gels with lower concentrations (4%, 5% and 7% CP) were synthesized and a gold standard gel, CP 10%, was used as a reference. Fifty-six premolars were randomly divided into four groups. Applications of the bleaching gel were made for 3 hours for 21 days. The bleaching efficacy was evaluated by digital spectrophotometry on days 1, 7, 14 and 21, with analysis in the CIELab, CIEDE 2000 and WID color spaces. The concentration of HP in the pulp chamber was measured in the same periods by UV-Vis spectrophotometry (μg/mL). Two-way repeated analysis of variance (ANOVA) examined bleaching efficacy and HP permeability, followed by Tukey's post-hoc test (α = 0.05). Results: All groups showed significant color changes, with no statistical differences after the second and third week of bleaching (p > 0.05). The ‘time’ factor was statistically different (p < 0.05), increasing the bleaching efficacy throughout the treatment. The 4% CP group had the lowest HP levels in the pulp chamber (p < 0.05). Conclusions: The results seem promising, revealing that low concentration gels are as effective as 10% CP with the benefit of reducing the amount of HP in the pulp chamber. Clinical Relevance: Low concentration carbamide peroxide (4 and 5%) maintains bleaching effectiveness, reduces the penetration of HP into the pulp chamber, and may reduce tooth sensitivity.