The U.S. Food and Drug Administration (FDA) website says that dental amalgam “is the silver-colored material used to fill teeth that have cavities.” The mercury concentration in a silver filling is about 50 percent by weight, the FDA reports, and when you chew food the filling emits a minute amount of mercury vapor.
Currently, the FDA is considering reclassifying dental amalgam to include a warning for people hypersensitive to mercury.
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