For VRS, the data from scores observed in each time of evaluation/session of bleaching will be submitted to the Mann-Whitney rank sum test. Despite the measurement of tooth sensitivity using VAS giving a continuous outcome, data assessed with this scale did not show a normal distribution (Shapiro-Wilk's test). Thus, data from VAS will be also analyzed by the Mann-Whitney rank sum test, while one test per time of evaluation will be carried out. All statistical analyses will be performed considering a 95% significance level (α = 0.05).