Cumulative Bisphenol A Release and Elution Kinetics from Pediatric Restorative and Orthodontic Resin-Based Materials: An In Vitro LC–MS/MS Investigation

Background: Bisphenol A (BPA) release from resin-based dental materials is a growing concern due to its potential endocrine-disrupting effects, particularly in pediatric patients. This in vitro study evaluated cumulative BPA release and elution kinetics from commonly used pediatric resin-based materials, due to the limited evidence available. Methods: Three restorative materials (Clearfil Majesty ES-2, Estelite Sigma Quick, and Stela Automix) and one orthodontic material (Transbond XT) were investigated. Eighteen disk-shaped specimens (5.5 mm in diameter and 2 mm in thickness) were prepared for each material and immersed in artificial saliva (pH 6.8) at 37 °C for 1, 7, and 28 days. BPA concentrations were quantified using liquid chromatography–tandem mass spectrometry (LC–MS/MS). BPA release kinetics were evaluated during the early (1–7 days) and late (7–28 days) release phases. Results: All investigated materials released measurable BPA concentrations, with cumulative BPA release progressively increasing up to 28 days. Clearfil Majesty ES-2 and Estelite Sigma Quick exhibited the highest cumulative BPA concentrations, whereas Stela Automix showed markedly lower values. Transbond XT also demonstrated measurable BPA release. For all materials, BPA release kinetics were significantly higher during the early phase than during the late phase (p < 0.001), indicating a non-linear release behavior over time. Conclusions: BPA release from pediatric restorative and orthodontic resin-based materials is material-dependent and characterized by progressive cumulative accumulation associated with significantly higher early-phase release rates. These findings highlight the importance of assessing the safety of resin-based materials used in pediatric dentistry.