Bisphenol-A Release from Modern Resin-Based Dental Composites: A Time-Dependent In Vitro Assessment

Resin-based dental composites are widely used in restorative dentistry; however, concerns persist regarding their potential release of Bisphenol-A (BPA), a compound with recognized endocrine-disrupting activity. This in vitro study evaluated the time-dependent release of BPA from four contemporary resin-based dental filling composites immersed in artificial saliva under different thermal conditions. Disk-shaped specimens (5.5 mm diameter and 2 mm thickness) of Estelite Sigma Quick, Clearfil Majesty ES-2, Omnichroma Flow, and Luna 2 were incubated in artificial saliva at physiological pH (6.8) at 37 °C and 44 °C. BPA concentrations were quantified after 1, 7, and 28 days using a validated UHPLC-MS/MS method. BPA release was observed for all materials except Luna 2, for which it remained below the limit of quantification (LOQ) at all time points and temperatures. Across all BPA-releasing composites, the highest concentrations were observed after 1 day of immersion, particularly at 44 °C. Estelite Sigma Quick exhibited the highest BPA release, followed by Clearfil Majesty ES-2 and Omnichroma Flow. BPA release decreased progressively over time for all materials. Statistical analysis confirmed significant effects of material type, temperature, and exposure duration on BPA release (p < 0.001). Within the limitations of this in vitro study, BPA release appears to be material-dependent and influenced by thermal conditions and immersion time. Although absolute BPA concentrations were low, these findings highlight the importance of material-specific evaluation and continued monitoring of potential sources of cumulative BPA exposure from restorative dental materials.