Bisphenol A Biomonitoring after Sealant Placement: A Prospective Cohort Study in Schoolchildren

Introduction: Bisphenol A (BPA), known for its endocrine-disrupting properties, is a concern when leaching from dental sealants. This study investigates the systemic BPA exposure following the placement of Bis-GMA-based dental sealants in Thai primary school students.Objectives: The main objective was to evaluate the changes in urinary BPA concentrations after the application of Bis-GMA dental sealants in a cohort of Thai students.Methods: In a prospective cohort of Thai primary school students participating in a voluntary sealant placement program, urinary BPA concentrations were measured at 4 time points: immediately before and on days 1, 7, and 14 after sealant application. BPA levels were measured using high-performance liquid chromatography. Repeated-measures analysis using generalized estimating equations was performed to determine the correlation between BPA concentration and time. Beta coefficient was used to estimate the mean change in BPA concentration following sealant placement. The associated cofactors were evaluated by calculating the incidence rate ratio.Results: Sixty-seven children (50.7% boys) with a mean age of 9.9 +/- 1.3 years and a body mass index of 17.7 +/- 4.4 kg/m2 participated. On average, students had 2.9 +/- 1.9 (range, 1-11) teeth with filled sealants. The median adjusted BPA levels before sealant placement and on days 1, 7, and 14 were 0.01, 0.03, 0.19, and 0.23 mu g/g creatinine, respectively. The analysis showed a significant association between the number of sealed teeth and increased BPA levels at all visits.Conclusion: The application of Bis-GMA-based dental sealants in children results in low-level systemic BPA exposure due to chemical leaching. Despite such a low level of BPA exposure, approved by international health authorities, it could be considered a silent, chronic, and persistent systemic event, the long-term implications of which are yet to be deciphered.Knowledge Transfer Statement: This research shows that Bis-GMA dental sealants cause minimal bisphenol A (BPA) exposure in children, within safe international limits. However, the long-term effects are unknown. This information should inform dental care practices and guide policymakers in assessing the chronic impacts of BPA exposure from dental materials.