High-performance liquid chromatography analysis of salivary bisphenol A levels from light-cured and chemically cured orthodontic adhesives.

INTRODUCTION: Our objective was to assess the levels of bisphenol A (BPA) released from light-cured and chemically cured resins used for orthodontic bracket bonding in 1 month.

METHODS: Saliva specimens were obtained at 5 time periods from 40 healthy patients treated with orthodontic mechanotherapeutics. The periods of collections were just before bonding orthodontic brackets, followed by 30 minutes, 1 day, 1 week, and 1 month after orthodontic bonding. The specimens were analyzed with the high-performance liquid chromatography/mass spectrometry method for quantitative evaluation of BPA levels.

RESULTS: We observed a large increase in BPA levels 30 minutes after orthodontic bonding in the 2 groups. Thereafter, there was sudden decline in BPA levels as time passed, and the levels reached a statistically significant level at 1 month after orthodontic bonding. Interestingly, the amount of BPA released from chemically cured resin was much higher; this was also significant statistically compared with light-cured resins.

CONCLUSIONS: The results of this in-vivo approach with high-performance liquid chromatography on salivary specimens confirmed continued release of BPA after bonding brackets for 1 month, although in smaller quantities. The release during the initial 30 minutes is high, making it essential to introduce measures to dilute it for better patient safety.