Quantification of Bisphenol A in the Saliva of Patients Wearing Clear Aligners

Background/Objectives: To analyze the behavior and release of bisphenol A (BPA) in the saliva of patients wearing clear aligners, and to evaluate differences in BPA levels between patients treated with aligners from the market-leading brand and those treated with in-office aligners. For the in-office group, 0.762 mm (0.30") thick thermoforming sheets from Ortolan^® were used to fabricate the aligners. Methods: Patients about to begin orthodontic treatment with clear aligners in the Master's degree program in Orthodontics at the University of Valencia were recruited for this prospective observational study. Patients were divided into two groups based on the type of aligners: The Invisalign^® group and the In-Office aligner group. Four saliva samples were taken from each patient at different times during treatment, with a one-week follow-up. The samples were stored at -80 °C and analyzed using mass spectrometry. Results: A total of 24 patients were included in the study, with 12 patients in each group. A statistically significant difference was found between baseline BPA levels and the increase observed half an hour after bonding the attachments. After a week, values returned to pre-treatment levels. Furthermore, BPA levels changed significantly during the follow-up period and were similar in both groups. Conclusions: An immediate increase was observed when the attachments were bonded with both treatments; however, differentiation from the 'peak' and recovery to baseline values was faster in patients treated with In-Office aligners. In those treated with Invisalign^®, after the placement of the aligners, values recorded were not significantly different from baseline, nor from the previous peak.