Dental Composites - a Low-Dose Source of Bisphenol A?

Objectives: Concerns about bisphenol A (BPA) have increased in the last decades due to its hormone-disrupting effects. As dental composite materials often contain Bis-GMA-type monomers with BPA structure in their molecules, they could be a low-dose source of BPA. The purpose of this study was to determine the maximal amounts of BPA released from “BPA-free” and Bis-GMA-containing restorative composites, and the kinetics of BPA release to methanol using liquid chromatography tandem mass spectrometry (LC-MS/MS).
Methods: “BPA-free” composites Charisma Diamond (CD) and Admira Fusion (AF) and Bis-GMA-containing Charisma Classic (CC) and Filtek Ultimate (FU) were used in this study. Specimens (diameter 6 mm, height 2 mm, n=3) were light-cured from one side (20 s, 1000 mW/cm²) and stored at 37 °C in methanol which was changed after 1, 7, 15 and 30 days. BPA concentrations were measured using dansyl chloride derivatization method with LC-MS/MS detection. The amount of BPA was expressed in nanogram per gram of composite (ng/g).
Results: The total amount of BPA released from “BPA-free” composites CD (0.27±0.10 ng/g) and AF (0.37±0.05 ng/g) after 30 days were significantly lower than from CC (6.05±0.28 ng/g) and FU (5.77±0.45 ng/g). Within the first day, all materials showed a high BPA release which decreased to the minimum at 7 days followed by a slight increase. With CD, the BPA values remained close to the lower limit of quantification.
Conclusions: BPA was even detected in “BPA-free” composites, although in significantly lower amounts than in the conventional Bis-GMA composites. As the total amounts of BPA released within 30 days were substantially lower than the tolerable daily intake 4 mg/kg bw/day, these materials should not pose a health risk according to the current criteria if adequately polymerized.