FDA reopens debate on dental amalgam fillings

The safety of dental fillings containing the toxic metal mercury will be debated at public hearings later this year, the U.S. Food and Drug Administration announced Friday.

Mercury-containing material used extensively in Canada, U.S.

The safety of dental fillings containing the toxic metal mercury will be debated at public hearings later this year, the U.S. Food and Drug Administration announced Friday.

Amalgam fillings, which contain mercury and other metals, are commonly used by dentists in Canada and the United States. Both nations have declared the fillings to be safe, but a public outcry in the U.S. has prompted a review of the evidence.

A citizen's petition filed with the FDA in July 2009 asks the agency to "formally ban the use of encapsulated mercury fillings as dental restorative material."

"The scientific community has long known that elemental mercury is a highly toxic heavy metal," says the petition, one of four submitted to the FDA. "Many prominent scientists have recommended the discontinuation of mercury fillings as a dental restorative material."

A second citizen's petition, filed in September 2009, calls on the FDA to require dentists to warn adult patients about the dangers of the fillings and to not allow its use in children under age six, pregnant women, nursing mothers and anyone who has a health condition that makes them sensitive to mercury exposure.

All of the petitions filed with the FDA oppose the use of amalgam fillings. The primary concern is that mercury from the fillings might leach into the body and accumulate, possibly causing damage to the kidneys or central nervous system.

Canadian research raises questions

In 1995, biologist Mark Richardson was commissioned to study the risks of amalgam fillings on behalf of Health Canada's Medical Devices Bureau.

Richardson's 120-page, peer-reviewed report raised serious concerns about the level of mercury leached from fillings and its potential to damage human health.

Richardson suggested a tolerable daily limit of mercury exposure that would prevent potential damage to human health.

The report suggested that toddlers and children get not more than one filling, teens three and adults and seniors four.

In its response to the Richardson report, Health Canada said there was not enough data to link specific exposures to amalgam fillings with potential health problems.

In a second report prepared by Health Canada, titled The Safety of Dental Amalgam, the public health agency acknowledges that dental amalgam is the single largest source of mercury exposure for the average Canadian but concludes that current evidence does not indicate that dental amalgam is causing illness in the general population.

In a position statement on amalgam, the Canadian Dental Association states, "although amalgam fillings release minute amounts of mercury vapour, current scientific consensus supports the position that amalgam does not contribute to illness."

No one from the dental association was available to comment on the FDA's decision on Friday.

However, the vice-president of the Alberta Dental Association told CBC News amalgam fillings are being used less in Canada.

"It's probably more common to use the white composite filling materials now," said Robert Huff, a dentist in Calgary. "Some of that is people have been reading these sort of reports and have concerns, and quite a big part of it is also esthetics because the white ones are a lot nicer looking."

The FDA's advisory panel will meet Dec. 13 and 14 to review the latest scientific evidence.

Sweden and Norway have already banned the use of amalgam fillings.