Statistical analysis
’ compliance behavior, tooth
Statistical analysis was performed using a statistical software package (IBM SPSS Statistics 22.0; IBM Analytics, Armonk, NY, USA). The Kolmogorov-Smirnov test was used to evaluate the normality of the results. The chi-square test was used between the groups to compare the volunteers’ compliance behavior (usage time). The results for tooth color change and sensitivity were submitted to a two-way analysis of variance (ANOVA), followed by a Tukey post-hoc test. Statistical analysis was performed at a 5% significance level.