Sunday, July 13, 2008
Chew on this: The fillings in your teeth might be hazardous to your health and that of the planet.
Millions of Americans have cavity fillings made of amalgam, a blend of about 50 percent mercury, a neurotoxin, plus tin, silver and other metals. (Fillings called "silver" are actually amalgam.) Although they've been widely used for more than 150 years, some people say amalgam fillings can emit mercury, causing damage to the brain, kidneys or nervous system.
Several studies published in medical journals have linked amalgam fillings to increased levels of bodily mercury. But not everyone is convinced: Matthew Messina, a spokesman for the American Dental Association and a practicing dentist in Ohio, says that "dental amalgam is a stable, solid compound."
A recently settled lawsuit, filed against the Food and Drug Administration by a group led by an organization called Moms Against Mercury, will require the FDA to complete its unfinished process of reviewing and possibly reclassifying amalgam fillings by next July. Now a Class I device, amalgam might be reclassified to Class II, which means that special controls would be issued governing its use. Those could be anything from simply requiring that patients be notified of the potential risks of mercury before receiving fillings to restricting amalgam's use in vulnerable populations such as pregnant women and small children.
The FDA's Web site recently changed its statement on amalgam. The site previously said that government agencies "have found no scientific studies that demonstrate dental amalgam harms children or adults." It now says that mercury in fillings "may have neurotoxic effects on the nervous systems of developing children and fetuses." It also states that "Pregnant women and persons who may have a health condition that makes them more sensitive to mercury exposure, including individuals with existing high levels of mercury bioburden, should not avoid seeking dental care, but should discuss options with their health practitioner."
The World Health Organization's policy paper on mercury released in 2007 states that "In 1991, the World Health Organization confirmed that dental amalgam is the greatest source of mercury vapour in non-industrial settings, exposing the concerned population to mercury levels significantly exceeding those set for food and air." It recommends that countries "support a ban on use of mercury-containing devices."
Should you avoid amalgam for new fillings? It's not a bad idea. Should you have your old ones taken out? It depends; the dental association doesn't recommend that. Many dentists will remove and replace fillings, but the removal must be done carefully, or the risk of exposure will be even greater than that of leaving them in. Mercury from amalgam going down the drain or into a landfill is another environmental issue. The dental association encourages, but does not require, dentists to recycle waste metals. It also suggests that dentists use amalgam separators, which prevent most mercury particles in water from reaching the sewer system and waterways. If you're having fillings removed, ask your dentist about exposure-prevention methods, and make sure the office uses an amalgam separator.
Regardless of whether amalgam fillings will be phased out altogether, the popularity of tooth-colored composite and porcelain fillings has skyrocketed. "That's not because they're green," Messina says, "but because they're white."
-- Eviana Hartman