Dear EarthTalk: Are silver dental fillings, which contain mercury, toxic?
Despite their name, “silver” fillings are actually composed of about 50 percent mercury and 30 percent silver, with the remaining components divided among copper, tin, zinc and sometimes cadmium. Dozens of Americans have complained that the fillings have damaged their health through mercury poisoning, from causing shortness of breath, loss of energy, memory damage and even partial paralysis.
Silver fillings, which are also called amalgam, are cheap and easy to install, and the American Dental Association (ADA) reports that 76 percent of dentists use them. Although the ADA concedes that “a very small number of people” are allergic to the fillings, the group staunchly maintains, “Studies have failed to find any link between amalgam restorations and any medical disorder.”
The ADA has long claimed that mercury remains chemically locked within the “extremely stable” fillings, but according to the U.S. Agency for Toxic Substances and Disease Registry, “Very small amounts are slowly released from the surface of the filling due to corrosion or chewing or grinding motions.” Although the agency agrees with the ADA that there is not yet scientific agreement on whether this exposure actually does cause health problems, it suggests that fillings may be risky for pregnant women, children and those with impaired kidney or immune function.
The citizen group, Consumers for Dental Choice, argues that mercury fillings do pose a significant threat to public health, and they are campaigning to end the practice. And despite strong industry opposition, Congresswoman Diane Watson (D-CA) introduced still-pending legislation in April 2002 that would ban all mercury-based dental amalgam within five years.
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