Hydrogen Peroxide in the Pulp Chamber and Color Change in Maxillary Anterior Teeth After In-Office Bleaching

While the literature has noted variations in hydrogen peroxide (HP) permeability, and consequently, tooth sensitivity among different types of anterior teeth, there is a scarcity of research on this specific topic. This study evaluated HP permeability and color change (CC) in different groups of human maxillary anterior teeth (canines, lateral incisors, and central incisors) after in-office bleaching with HP at 35%. Thirty teeth maxillary anterior (n=10) were bleached with HP at 35% gel in one session of three 15-minutes applications. Buccal thickness (mm) was measured from images obtained using cone beam computed tomography. The concentration of HP (µg/mL) that reached the pulp chamber was assessed using UV-Vis spectrophotometry. CC (WID, ∆Eab, and ∆E00) was evaluated before and after bleaching with a digital spectrophotometer. One-way ANOVA and Tukey's test were applied to statistically evaluate the data for buccal thickness, HP permeability, and CC (α=0.05). Comparison between thickness and HP permeability was performed using Pearson's correlation. Thicker teeth, such as canines, had lower HP amounts inside the pulp chamber compared to central and lateral incisors. Despite the significant effect of buccal thickness on HP permeability (p<0.05), no correlation was found between the two factors. CC was similar across tooth types (p>0.05). The difference in buccal thickness among the superior anterior teeth does not interfere with CC. However, a thinner buccal wall thickness is associated with greater HP permeability detected in the pulp after in-office bleaching.