Amalgam dental fillings - which contain the highly toxic metal mercury - pose a health risk, the world's top medical regulatory agency has conceded.
After years of insisting the fillings are safe, the US government's Food and Drug Administration (FDA) has issued a health warning about them. It represents a landmark victory for campaigners, who say the fillings are responsible for a range of ailments, including heart conditions and Alzheimer's disease.
Earlier this month, in an unprecedented U-turn, the FDA dropped much of its reassuring language on the fillings from its website, substituting: "Dental amalgams contain mercury, which may have neurotoxic effects on the nervous systems of developing children and foetuses." It adds that when amalgam fillings are "placed in teeth or removed they release mercury vapour", and that the same thing happens when chewing.
The FDA is now reviewing its rules and may end up restricting or banning the use of the metal.