Long-term elution of bisphenol A from dental composites

Objectives. BPA release from composites on the short term has been reported in several in-vitro and in-vivo studies. However, it remains unclear whether these materials also leach BPA on the long term. Even though composites may release various (BPA-based) methacrylate monomers up to one year, quantitative data about BPA have not been reported due to the lack of a sensitive method to accurately quantify low levels of BPA. In this context, the aim of the study was to quantify the one-year release of BPA with an optimized analytical method. Methods. Composite disks (n = 6, 6 mm diameter and 2 mm height) from four commercial materials (G-genial Posterior, Venus, Ceram.x mono and Filtek Supreme XTE) were immersed in 1 mL of water or ethanol as extraction solvent and stored in the dark at 37 degrees C. The extraction solvent was renewed weekly for a period of 52 weeks. Samples were derivatized with pyridine-3-sulfonyl chloride before analysis with ultra-pressure liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Results. Derivatizing BPA increased the sensitivity of the analytical method and allowed accurate quantification of very low levels of BPA (i.e. 0.78 pmol BPA). BPA eluted continuously in ethanol from all four tested composites over a period of one year. BPA elution was clearly higher when ethanol was used as extraction solution. In water, BPA eluted could be detected up to one year, but levels could not be accurately quantified anymore after several weeks. Significance. Composites can be considered as a potential long-term source of BPA, and thus should not be neglected when assessing the overall exposure to endocrine disrupting chemicals. (C) 2021 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

Automated summary

The study successfully quantified the one-year release of BPA from four commercial materials using an optimized analytical method. Results showed that BPA continuously eluted from all tested composites over a year when ethanol was used as the extraction solvent, while in water, BPA release could be detected for up to a year but levels could not be accurately quantified after several weeks.