Longitudinal analysis of the association between removal of dental amalgam, urine mercury and 14 self-reported health symptoms

Mercury vapor poses a known health risk with no clearly established safe level of exposure [1]. Amalgam dental fillings are one of the largest sources of exposure to mercury in the general population. Our study shows individuals with dental amalgam fillings have double the measured urine mercury compared to a control group of persons who have never had amalgam fillings. Removal of amalgam fillings in persons with urine mercury levels, considered by Health Canada to be too low for adverse health effects, decreases measured urine mercury to levels in persons without amalgam fillings and reduces the odds of deterioration in self-reported health symptoms compared to a sample of persons who did not have their fillings removed within the one year timeframe. The likelihood of symptom improvement in comparison to people who retained their amalgam fillings was also increased. Health Canada’s position statement on amalgam removal indicated that there was not sufficient evidence of adverse health effects due to mercury exposure to support a total ban of amalgam or removal of amalgams from patients. Ultimately our findings suggest that mercury could have toxic effects at low levels of exposure. The use of safer alternative materials for dental fillings should be encouraged to prevent an unnecessary risk of health deterioration associated with mercury exposure from dental fillings.