Except for special populations such as occupationally exposed workers and populations with a high level of fish in the diet, the number one source of mercury in most people has been documented to be dental amalgam fillings[13,24-31]. Most of the thousands of people with several amalgam fillings who have been tested were found to have daily exposure levels of mercury vapor exceeding government safety guidelines. The U.S. ATSDR mercury vapor minimum risk level(MRL) is 0.2 micrograms per cubic meter(ug/M3)[32]. Most people with amalgam fillings who have been tested have been found to have much higher levels of mercury in their oral air than this, with some as high as 100 ug/M3[24,25,28-31].For an adult breathing 0.2 ug/day of mercury and breathing approximately 20 cubic meters per day of air[27], the ATSDR MRL gives a guideline level of exposure of approx. 4 micrograms per day. Most of the many thousands tested who have 9 or more amalgam fillings were found to have exposure levels above this level and above U.S. government health guidelines for mercury[11,13,24-31]. While most studies such as Richardson's analysis for Health Canada[27] that are primarily based on urine measurements use conservative estimates of daily mercury exposure from amalgam in the range 3 to 5 ug/day, studies which measure levels of mercury in feces or saliva found considerably higher daily exposure levels. Two studies found daily exctetion in feces betweeen 30 to 190 ug for subjects with between 18 and 82 amalgam surfaces, with an average of 60 ug/day[25,28].Visit our: Dental Forum
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