Statistical analysis
The statistician was blinded for both groups and the analysis involved all participants and followed the intent-to-treat protocol. Two one-sided t-tests for paired samples (TOST-P) were performed to test the equivalence of the study groups at the different evaluation points. Regarding the evaluation of color change, a paired Student’s t-test was used for all scales and evaluation time points. The absolute risk of TS was compared using the McNemar test. Odds ratios were also estimated, as well as the confidence interval (CI) and Spearman correlation. The intensity of TS was analyzed using the paired Student’s t-test, and differences between the groups were detected by the Pearson correlation. Aesthetic self-perception was assessed using the paired Student’s t-test. All statistical tests were performed with an alpha of 5%.