Does mercury from amalgam restorations constitute a health hazard?
Amalgam is the most extensively used implant material in dentistry. There have been no clinical trials of this substance and there are no epidemiological studies that allow any conclusions on the safety of amalgam fillings. Amalgam restorations continuously emit mercury vapour, which is absorbed in considerable quantities via the lungs. A comparison with dose-effect relationships, obtained in occupational studies, for certain effects on the kidneys and central nervous system (CNS), suggests that individuals with unusually high emission of mercury from amalgam fillings are at risk. It is unclear whether or not clinically significant effects could be expected. The limited sensitivity of available occupational studies, together with insufficient knowledge of possible host factors affecting resistance to mercury, implies that other more severe effects in susceptible individuals cannot be excluded. Information on long-term effects on organs other than brain or kidney is sparse. Animal studies suggest the possibility of immune system reactions to mercury, i.e. development of autoimmunity, that are not primarily dose-dependent, but rather depend on genetic susceptibility. From a toxicological point of view, amalgam is an unsuitable material for dental restorations.