Sep 7, 2010 4:16 PM by Linda Carroll
Widely used dental sealants and tooth repair resins contain substances that degrade into the controversial chemical BPA, but dentists can use the product safely in kids if they make sure to wipe or rinse away residue after treatment, a new study concludes. Pregnant women, however, might do better to wait until after delivery.
The benefits of sealants in preventing kids' cavities outweighed risks associated with bisphenol A, or BPA, the chemical linked to a host of health ills and banned by many plastic bottle manufacturers, researchers find in the report published in the latest issue of the journal Pediatrics.
"People shouldn't be scared by this," said Dr. Burton Edelstein, chairman of social and behavioral sciences at the Columbia University College of Dental Medicine and a co-author on the study. "The amount of exposure is extremely low. And the layer that contains BPA can be wiped off with cotton or rinsed off with a stream of water that can then be suctioned away by the dental assistant."
BPA sparked alarm after several studies linked the chemical to health problems, prompting many manufacturers of plastic bottles, particularly those used by children, to change their formulations to exclude the substance. In January, federal Food and Drug Administration officials called for more research on the chemical, explaining that the agency had "some concern about the potential effects of BPA on the brain, behavior and prostate glands of fetuses, infants and children."
The team of toxicologists and dentists who reviewed the scientific literature for the report concluded that the benefit of making sure children's teeth are protected against decay was greater than the risk posed by brief exposure to BPA. In the U.S., depending on age, between 20 percent and 40 percent of children had been treated with sealants between 1999 and 2004, and the proportion is likely higher now because of aggressive efforts to improve dental hygiene.
But the article also cautioned that pregnant women should wait whenever possible on dental procedures involving BPA-associated resins until after their babies are born.
"If the woman is in serious need of dental work during pregnancy, she should go ahead and get her teeth fixed," said Dr. Philip J. Landrigan, a study co-author and director of the Children's Environmental Health Center at the Mount Sinai School of Medicine and. "If it's something that can wait, in the spirit of precaution, we would encourage the woman to wait till after her baby is born."
BPA derivatives are increasingly used in dental resins and sealants, which have gained in popularity since the mid-1960s, the report noted. They are used for all dental patients, but children, pregnant women and their developing babies are particularly susceptible to the effects of chemicals.
Edelstein and other dentists interviewed by msnbc.com argued that there are ways to protect even pregnant women from BPA, including using rubber "dams" that isolate the tooth being repaired from the rest of the mouth. BPA is released only when certain chemicals in the resins come in contact with saliva, he said.
"Frankly, I think the article is going a bit beyond the current level of evidence when it comes to pregnant women," said Dr. Jim Crall, a professor of pediatric dentistry at the University of California at Los Angeles. "And it's maybe a little overcautious. The science around this is still pretty sketchy as relates to dental exposure."
Both dentists said they worried that women would get the wrong message from the article and skip dental care altogether. Edelstein emphasized the importance of dental hygiene and the potential health impact of untreated gum disease on the developing fetus.
Some toxicologists, however, suggested that the article's recommendations didn't go far enough. Fred von Saal, a leading expert on BPA, believes that children should receive sealants only if they have a clear tendency to develop tooth decay.
"This chemical is one that you should not be exposed to at any level," said von Saal, Curators' professor of biology at the University of Missouri at Columbia. "There are lots of sources of BPA and you want to avoid anything that adds to your body's burden. And the younger you are, the more sensitive you are to this chemical."
National surveys conducted by the federal Center for Disease Control and Prevention have revealed measurable levels of BPA metabolites in the urine of more than 95 percent of U.S. residents, even though the compound has a short half-life and should be eliminated quickly from the body. That indicates that people are repeatedly and frequently exposed to BPA, experts say.
The solution, said Von Saal and others, is for resin manufacturers to come up with a dental product that doesn't lead to BPA exposure.
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