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    Mercury Fillings: They're Not Risky

    Mercury Vapors Not Easily Absorbed by Body

    Why Mercury Fillings Are Safe

    Mercury amalgam fillings are "100% safe," says J. Rodway Mackert, DMD, PhD, professor of dental materials at the School of Dentistry of the Medical College of Georgia in Augusta. Mackert is a spokesman for the American Dental Association.

    In fact, the World Health Organization, the Alzheimer's Association, and the National Multiple Sclerosis Society have all issued statements with a similar message, Mackert tells WebMD.

    "Dental amalgam restorations are considered safe," says a WHO consensus statement. In rare instances, there is an allergic reaction to the filling, the statement notes. However, "the small amount of mercury released from amalgam restorations, especially during placement and removal, has not been shown to cause any other adverse health effects."

    "According to the best available scientific evidence, there is no relationship between silver dental fillings and Alzheimer's," says the Alzheimer's Association web site.

    "There is no scientific evidence to connect the development of multiple sclerosis (MS) with mercury-based dental fillings," says the National Multiple Sclerosis Society web site. "Poisoning with heavy metals, such as mercury, lead, or manganese, can damage the nervous system and produce symptoms, such as tremor or weakness, similar to those seen in MS. However, the underlying mechanism of nerve damage is different from MS, as is the pattern of illness caused by heavy metal poisoning."

    The Science

    In creating amalgam fillings, mercury is chemically combined with silver, Mackert explains. It's the chemical reaction between powdered silver and tin -- and liquid mercury -- that creates a material stable and safe enough for the human mouth.

    "When liquid mercury is combined with silver, the chemical reaction reduces the amount of mercury that is released by nearly 1 million-fold," Mackert tells WebMD. "That's why it can be used in fillings."

    Questions about mercury fillings began surfacing in 1979, when technology became available to measure the mercury vapor that the fillings emitted, he explains. "When we could measure the vapor, we found it wasn't zero, but it was a very small number. That was the concern. People began looking at how much vapor is released and the effects."

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