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Dental sealants, plastic coatings that can protect teeth from cavity-causing bacteria, may release the estrogenic chemical bisphenol-A (BPA), which is linked in animal studies to decreased sperm production, early puberty and miscarriage. Recently, BPA was also linked to diabetes and heart disease. Dentists commonly apply sealants to hard-to-clean molars, using them on 32 percent of U.S. children, according to the Centers for Disease Control and Prevention (CDC).

Some sealants contain BPA and can release it into the body during application, according to a study in the March 2006 Journal of the American Dental Association. Researchers tested 14 volunteers immediately after sealant application and found that patients who received Delton Light Cure (LC) Opaque brand absorbed about 110 micrograms of BPA, 20 times that absorbed by recipients of another brand, Helioseal F (5.5 micrograms). Delton Light Cure (LC) leached amounts similar to those that caused developmental toxicity in rodent studies and, at 42.8 parts per billion (ppb), are higher than the highest amount found in canned food, 38 ppb.

"We believe this is because there is incomplete curing of the sealant," says Dana Barr, Ph.D., a research chemist at the CDC. "If the patient doesn't spit it out, he or she will likely swallow it." The American Dental Association's position on BPA states, "there is no evidence to suggest a link between any adverse health condition and BPA leached out of dental sealants."

What You Can Do

• If a dentist suggests sealants for you or your child, ask why, whether it's necessary on baby teeth and whether decay may be avoided by improving diet and hygiene first.
• If you are considering sealants, ask your dentist or call the manufacturer to check for BPA. Composite fillings can also contain this chemical.
• To limit childhood exposures, ask your dentist to help you find BPA-free sealants.
• If you decide on sealants, immediately after the sealant is applied, chew on a cotton pad to induce saliva and then spit out as much as you can into the sink.