(WASHINGTON) -- A federal advisory panel is trying to decide whether the U.S. Food and Drug Administration relied on adequate science when it determined last year that mercury amalgam can safely be used to fill cavities in healthy people. At the time, the FDA didn't find evidence that dental mercury hurts developing fetuses, young children and those more sensitive to its potential health effects.
The FDA's scientific review of evidence about dental amalgam fillings, commonly called "silver fillings" because of their silver-gray color, found them safe for adults and children at least six years old. Dental amalgam is an approximately 50-50 mixture of liquid mercury and powdered metal alloy of silver, tin and copper. When mixed, it forms a pliable putty-like substance that hardens into place.
The mercury in amalgam fillings, called elemental mercury, releases small amounts of mercury vapor -- a substance that at high levels can be toxic to the brain and kidneys. Vapor levels are highest right after fillings have been placed in a tooth, and later if they're being removed or replaced. People trying to stop the use of mercury in dentistry say mercury vapor levels are boosted by chewing, eating, brushing teeth and drinking hot liquids.
"Even in adults and children ages 6 and above who have 15 or more amalgam surfaces, mercury exposure due to dental amalgam fillings has been found to be far below the lowest levels associated with harm," according to an FDA document titled About Dental Amalgam Fillings.
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