FDA warns of mercury in fillings

WASHINGTON — Silver dental fillings contain mercury, and the government for the first time is warning they might pose a safety concern for pregnant women and young children.

The Food and Drug Administration (FDA) posted the precaution on its Web site this month to settle a lawsuit, making the move a victory for anti-mercury activists.

The warning is not aimed at the general population, only at two groups already urged to limit mercury from another source — seafood — because too much can harm a developing brain.

The fillings, formally known as dental amalgams, "contain mercury, which may have neurotoxic effects on the nervous systems of developing children and fetuses," reads the FDA Web posting.

That doesn't mean it truly harms, and the FDA advises against removing existing fillings.

The agency is studying whether the small amount of mercury vapor released by chewing and brushing is enough to cause neurologic disorders or other problems in youngsters. There have been a handful of rigorous studies comparing children given either amalgam fillings or tooth-color resin composite fillings that are mercury-free — and those studies haven't detected any brain problems.

Nor has that research settled the scientific controversy. Two years ago, the FDA's independent scientific advisers said that while amalgam fillings were safe for most people, more research was needed about potential effects on fetuses and children younger than 6.

And this spring, the FDA put dentists on notice that it is considering additional controls, including whether to require warnings that would advise consumers of the mercury in amalgams before they have a cavity filled or perhaps restrict use in young children and certain other patients. It is accepting public comments until July 28.

"It's an open question what we will do [but] what this says is there's a clear intent on our part on labeling for sensitive subpopulations," FDA Deputy Commissioner Randall Lutter said.

A final ruling is expected by July 28, 2009, a date set by the legal settlement.

"It's a watershed moment," said Michael Bender of the Mercury Policy Project, which, with other advocacy groups, had sued the FDA in hopes of forcing restrictions on amalgams.

"This court settlement signals the death knell for mercury fillings," added Charles Brown, an attorney for Consumers for Dental Choice.

Not so fast, said some dentists who point to medically crucial reasons to use amalgams and worry that people who can't afford more expensive alternatives might avoid dental care. "We don't want these choices taken away based on junk science," said Dr. Edmond Hewlett, a dental professor at UCLA and an American Dental Association adviser.

Amalgam fillings are about 50 percent mercury, joined with silver, copper and tin. The hardened mixture makes the mercury less absorbable by the body than the kind found in fish, Hewlett said.

Amalgams account for about 30 percent of U.S. fillings, which still affects millions of people a year.

They're cheaper than alternatives — roughly $100 for an amalgam filling versus $150 or more for a composite, Hewlett estimated — and they're durable.

Hewlett said two conditions demand amalgams: spots on back teeth that dentists can't keep dry long enough for a composite filling to bond and in people who grind their teeth.