Efeito de dentifrícios clareadores com diferentes concentrações de peróxido de hidrogênio: penetração na câmara pulpar e alteração de cor

Abstract

The desire of smile aesthetics has encouraged individuals to look for different methods of tooth bleaching. Low-cost over-the-counter products, such as toothpaste with varying concentrations of hydrogen peroxide (HP), are often introduced to the market with the promise of providing effective tooth whitening. The aim of this study was to evaluate the efficacy of using whitening toothpaste containing different concentrations of HP in penetrating the pulp chamber and causing color change in human teeth. Additionally, the physicochemical properties of initial HP concentration, pH, and viscosity were assessed. Forty-nine premolars were randomized into seven groups (n = 7): no treatment (control); whitening gel (White Class 6%, 6%BG) evaluated with a single application of 90 minutes (6%BG AH 90min) and 14 applications of 90 minutes each (6%BG AH 14x90min); whitening toothpastes (Colgate Luminous White Glow 3%, 3%TP; Crest 3D White Brilliance 4%, 4%TP; Colgate Optic White Pro Series 5%, 5%TP); and the gel (6%BG TB 14x90s) brushed 14 times for 90 seconds each. The penetration of HP into the pulp chamber was measured by UV-VIS spectrophotometer and converted into equivalent concentration (μg/mL). Color change was assessed with a digital spectrophotometer (ΔEab, ΔE00, and ΔWID). Initial concentration, pH, and viscosity were measured by titration with potassium permanganate oxidizing agent, digital pH meter, and controlled shear rheometer, respectively. Statistical analysis was performed using one-way ANOVA, Tukey's test, and Dunnett's test (α = 0.05). The 6%BG (14x90min) and 4%TP groups showed acidic pH and higher HP concentration in the pulp chamber compared to the other groups (p < 0.05). On the other hand, the 3%TP and 5%TP groups exhibited alkaline pH, higher viscosity among the toothpastes, and lower HP concentrations in the pulp chamber (p < 0.05). The 6%BG AH (14x90min) group exhibited the greatest color change (ΔEab, ΔE00, and ΔWID) (p < 0.05). The results of HP concentration and color change of 6%BG varied according to the application. The application of an acidic pH whitening toothpaste resulted in higher penetration of HP into the pulp chamber. However, even when a high concentrated HP whitening toothpaste was used, a lower whitening effect was observed when compared to a two-week at-home bleaching.