Is Mercury in Fillings Really a Problem?

Medically Reviewed by Jacqueline Brooks, MBBCH, MRCPsych

May 29, 2001 -- Chances are, you have had a tooth cavity that needed to be filled. It's a pretty common occurrence. But how often have you have stopped to wonder what those fillings contain -- and what you carry around in your mouth for decades?

According to the American Dental Association, or ADA, up to 76% of dentists use silver fillings containing mercury when filling a tooth. Although the substance used for silver fillings, known as amalgam, has been in use for more than 100 years, the fillings are controversial because of claims that exposure to the vapor from the mercury can cause a variety of health problems ranging from joint pain to multiple sclerosis.

The ADA maintains the fillings are safe and says studies have failed to find any link between silver fillings containing mercury and any medical disorder.

And the ADA is not alone in its position. The CDC, the World Health Organization, the FDA, and others support the use of silver fillings as safe, durable, and cost-effective. The U.S. Public Health Service has said there is no health reason not to use silver fillings, unless a patient has an allergy to a component in the amalgam. The ADA says fewer than 100 incidents of such allergy have ever been reported.

But Bill DeLong, DDS, a dentist in Ellicott City, Md., says the ADA's claim that the mercury in silver fillings doesn't cause health problems is "bogus."

DeLong, who does not use silver fillings, has been brought before his state dental board twice for talking to patients about the safety precautions he uses in his office -- including a mercury vapor detector -- when removing fillings for people who want or need them replaced.

"I had complaints ... about the fact that I discuss that with patients -- and in both instances they tried to either confiscate my instruments or get me to not discuss anything with my patients unless they bring it up first," says DeLong, one of five dentists who are suing in federal court for the right to discuss the potential harm of mercury in fillings or even post information in their offices informing patients of some of the studies that have linked the fillings to health problems.

"When people are seeking advice I think it's only right that they get to hear that there are other opinions," says DeLong, who had his own silver fillings removed 24 years ago.

DeLong uses the mercury detector to show patients how much mercury vapor is released from their fillings. Chewing and eating or drinking hot foods and beverages increase the amount of vapor that is released, although small amounts of vapor are released all the time.

The ADA insists once the filling is placed in the tooth, a person's exposure to mercury vapors is minimal.

"There have been a number of studies looking at the potential effects of mercury from amalgam in the general population, and the preponderance of evidence is that there is no relationship between the presence of amalgam fillings and any disease condition," says ADA spokesman J. Rodway Mackert, PhD.

"Therefore there's no reason for a patient to avoid placement of amalgam fillings, and there's no reason to have amalgam fillings removed for the purpose of trying to alleviate any disease condition," says Mackert, who is a professor at the Medical College of Georgia in Augusta.

But DeLong says by the standards of the Environmental Protection Agency, the amount of mercury in one filling is enough to contaminate a 10-acre pond, making the fish that live in the pond over the mercury limit for human consumption.

"It's hazardous waste," DeLong says of a filling that has been removed. "You have to dispose of it properly, you have to send it to an EPA-licensed facility that handles mercury waste -- this is the very material that just came out of a person's mouth."

There are numerous options to silver fillings, including tooth-colored resin, porcelain, and gold fillings -- all of which are considerably more expensive. Some dentists say colleagues who encourage patients to have silver fillings removed and replaced with the more expensive fillings are just making money off the controversy.

Charles G. Brown, the Washington attorney who represents DeLong, four other dentists, and seven patients in the lawsuit, says American dentists are dropping the ball on an important health issue.

"They know it is going to harm some people. They know, but they discourage warnings," says Brown. "They're keeping people in the dark ... they're incredibly biased on this issue."

The ADA, which is not named in the lawsuit, denies they ever discourage dentists from talking to patients about the issue.

"What we discourage is dentists misrepresenting to patients the value of any therapeutic treatment," says Kathleen Todd, ADA associate general counsel.

A New York City dentist who uses silver fillings agrees with the ADA that the amount of mercury in the fillings is not harmful and that the controversy over their safety is unwarranted.

"With the fillings of today, it's not a problem at all," says Nikolaos Laoutaris, DDS.

He says many people prefer the tooth-colored fillings to the silver fillings for cosmetic reasons anyway, so it may be becoming less of an issue.

But Laoutaris, director of the General Dentistry Program at New York Weill Cornell Medical Center, says he advises patients with fillings that are more than 25 years old to have them removed because the amount of mercury released increases with the age of the filling. Still, he says he doesn't discourage replacing them with silver fillings because the evidence does not support any harm associated with them.