Figure 1

Bleaching methods significantly alter teeth' biochemical profiles. (a) Boxplots of non-normalized whiteness index (WIO) show a significant difference between Control and H2O2/MPS bleaching methods. This is a whiteness index based on human perception studies, − WIO are darker teeth and + WIO are whiter teeth23. Analysis of variance (ANOVA) followed by Tukey’s Honestly Significant Difference (HSD) Test. ***p < 0.05. (b) PCA shows a clear separation between control and bleaching methods according to the Permutational Analysis of Variance (PERMANOVA), R2 = 0.27, p < 0.001. (c) Heatmap of the top 47 features with VIP scores > 1.00 extracted from pairwise PLS-DA models. The asterisks in the scores plots represent group centroids.