Just had a dental filling? You might be chewing on bisphenol A (BPA), a common plastics ingredient that could have harmful effects on your health.

While the evidence is still sparse, the chemical is suspected of playing a role in heart disease and certain cancers, and of causing abnormal brain development in children.

Writing in the journal Pediatrics, doctors caution that BPA-related compounds are common ingredients in plastic-based dental filling materials and sealants, which are brushed onto teeth to prevent decay.

"We would recommend avoiding sealants during pregnancy," said Dr. Abby Fleisch at Children's Hospital Boston, who led the research.

BPA-related compounds - such as bis-GMA - leech into the spit, where they are converted to pure BPA and can be found up to three hours after the filling was placed, according to the authors.

They note that between 20 percent and 40 percent of U.S. kids have sealants on their teeth, depending on age. But at this point they don't recommend abandoning sealants altogether, because they play an important role in oral health.

"In the case of sealant placements, the BPA exposure is transient and the health benefit to sealants is extensive," Fleisch said.

Still, she recommends a few precautionary steps, such as gargling for 30 seconds and spitting immediately after the sealant or filling has been placed to get rid of most of the free chemicals.
Alternatively, the dentist can rub with pumice on a cotton roll or use an air-water syringe in small children.

Some BPA-related compounds may be less problematic than others, and the authors say bis-GMA-based resins are generally preferable to those containing bis-DMA. But because not all manufacturers list the specific ingredients, it can be hard to know which one to use.

BPA, a man-made chemical, is found in a variety of everyday items - and in most humans, according to a new Canadian study. It is used to stiffen plastic bottles, line cans and make smooth paper receipts.

Exposure from dental materials is likely to be small compared with those sources, said Fleisch.
Because of its estrogen-like effects on the body, BPA is classified as a so-called endocrine disruptor. While such chemicals may cause a host of health problems, most of the direct evidence regarding BPA comes from animal studies that don't automatically translate to humans.

"A lot more research is needed to understand the full effects of BPA," Fleisch told Reuters Health.

Meanwhile, she advised, consumers should limit their exposure to the chemical and manufacturers should start looking for new materials without BPA-related compounds.