A new study shows that dental sealants used to treat and prevent cavities may expose children to an oestrogen-like chemical called BPA.
BPA, or bisphenol A, has been linked to a variety of health problems in human and animal studies, says Philip Landrigan, director of the Children's Environmental Health Center at the Mount Sinai School of Medicine in New York, and co-author of a study in Pediatrics, based in the US.
Studies have linked BPA to altered hormone levels in men and an increased risk of diabetes and heart disease in adults.
Depending on a child's age, 20-41% have had their teeth sealed, the study says.
The sealants can break down into BPA after coming in contact with saliva, says co-author Abby Fleisch, a paediatrician at Children's Hospital Boston.
BPA levels in saliva can increase to 88 times higher than normal immediately after a dental sealing, Fleisch says.
Tests can detect BPA in saliva for up to three hours after the procedures, although levels quickly drop off after that.
Doctors don't know how much BPA is absorbed into the body, however, or what its effects might be, Fleisch says.
But dental materials probably cause far less BPA exposure than other consumer goods, such as plastic bottles and the linings of metal cans.
Overall, the benefits of dental sealants outweigh the potential risks of a brief BPA exposure, says co-author Burton Edelstein, president of the Children's Dental Health Project, who continues to recommend the procedures.
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