An investigation into bisphenol-A leaching from orthodontic materials.

OBJECTIVE: To quantitatively determine the bisphenol-A (BPA) leached from orthodontic materials during simulated intraoral exposure. MATERIALS AND METHODS: Samples of orthodontic materials were subjected to simulated abrasion, immersion in artificial saliva, thermal shock via temperature cycling, and simulated intraoral exposure. Sample aliquots were collected for up to 2 weeks after artificial saliva immersion, derivatized, then analyzed for BPA by gas chromatography/mass spectroscopy. RESULTS: Quantifiable amounts of leached BPA were observed from a thermoformed orthodontic retainer material (7.63 microg/g of material) and an orthodontic adhesive (2.75 microg/g of material). BPA leaching was only observed within the first 3 days of artificial saliva immersion. CONCLUSIONS: Under the test conditions, BPA was observed to leach from two orthodontic materials. While the quantities of leached BPA were below the reference dose for daily intake, existing data of low-dose effects and medical disorders associated with elevated urinary BPA levels suggest that BPA exposure, and thus the use of the leaching materials identified in this study, should be reduced or eliminated.