This study investigates the estrogenic activity of resin-based composites and sealants used in dentistry. The researchers found that a sealant based on bisphenol-A diglycidylether methacrylate (bis-GMA) increased cell yields, progesterone receptor expression, and pS2 secretion in human estrogen-target, serum-sensitive MCF7 breast cancer cells. The estrogenicity was attributed to bisphenol-A and bisphenol-A dimethacrylate, monomers present in the base paste of the dental sealant. Saliva samples from subjects treated with a bis-GMA-based sealant showed the presence of bisphenol-A, confirming its release into the oral environment. The study highlights the potential contribution of bis-GMA-based resins, particularly sealants, to human exposure to xenoestrogens, with implications for health and reproductive systems.This study investigates the estrogenic activity of resin-based composites and sealants used in dentistry. The researchers found that a sealant based on bisphenol-A diglycidylether methacrylate (bis-GMA) increased cell yields, progesterone receptor expression, and pS2 secretion in human estrogen-target, serum-sensitive MCF7 breast cancer cells. The estrogenicity was attributed to bisphenol-A and bisphenol-A dimethacrylate, monomers present in the base paste of the dental sealant. Saliva samples from subjects treated with a bis-GMA-based sealant showed the presence of bisphenol-A, confirming its release into the oral environment. The study highlights the potential contribution of bis-GMA-based resins, particularly sealants, to human exposure to xenoestrogens, with implications for health and reproductive systems.