Time-dependent changes in salivary bisphenol A and bisphenol S concentrations during clear aligner therapy: a...

This prospective clinical study investigated time-dependent changes in salivary bisphenol A (BPA) and bisphenol S (BPS) concentrations during clear aligner therapy. 20 participants were treated with Invisalign® clear aligners. Stimulated saliva samples were collected before aligner insertion at baseline (Day 0) and on Days 3, 7, 14, and 21. BPA and BPS concentrations were measured using commercially available enzyme-linked immunosorbent assay kits. Changes across time points were assessed using the Friedman test, followed by Bonferroni-adjusted Wilcoxon signed-rank tests for pairwise comparisons. BPA concentrations changed significantly over time (p = 0.0021). The highest mean BPA concentration was observed on Day 3 (4.85 ± 1.89 ppb), and the Day 3 concentration was significantly higher than those measured on Days 14 and 21. BPS concentrations also changed significantly over time (p = 0.0063), with the lowest mean concentration observed on Day 14 (2.79 ± 0.10 ppb). This value was significantly lower than those measured at baseline and on Days 3, 7, and 21. These findings indicate time-dependent changes in salivary BPA and BPS concentrations during clear aligner therapy. The observed temporal patterns do not establish material-specific release or systemic exposure.