Dental composite materials often contain monomers with bisphenol A (BPA) structure in their molecules, e.g. bisphenol-A glycidyl dimethacrylate (Bis-GMA). In this study, it was examined whether dental restorative composites could be a low-dose source of BPA or alternative bisphenols, which are known to have endocrine-disrupting effects. Bis-GMA-containing composites Charisma Classic (CC) and Filtek Ultimate Universal Restorative (FU) and "BPA-free" Charisma Diamond (CD) and Admira Fusion (AF) were examined. Specimens (diameter 6 mm, height 2 mm, n=5) were light-cured from one side for 20 s and stored at 37 °C in methanol which was periodically changed over 130 days to determine the kinetics of BPA release. BPA concentrations were measured using a dansyl chloride derivatization method with liquid chromatography - tandem mass spectrometry detection. The amounts of BPA were expressed in nanograms per gram of composite (ng/g). BPA release from Bis-GMA-containing CC and FU was significantly higher compared to "BPA-free" CD and AF. The highest 1-day release was detected with FU (15.4+/-0.8 ng/g), followed by CC (9.1+/-1.1 ng/g), AF (2.1+/-1.3 ng/g), and CD (1.6+/-0.8 ng/g), and the release gradually decreased over the examined period. Detected values were several orders of magnitude below the tolerable daily intake (4 microg/kg body weight/day). Alternative bisphenols were not detected. BPA was released even from "BPA-free" composites, although in significantly lower amounts than from Bis-GMA-containing composites. Despite incubation in methanol, detected amounts of BPA were substantially lower than current limits suggesting that dental composites should not pose a health risk if adequately polymerized.

Institute of Dental Medicine 1st Faculty of Medicine of the Charles University and General University Hospital Prague Czech Republic

Institute of Endocrinology Prague Czech Republic

University of Chemistry and Technology Prague Czech Republic

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