Mercury inductions in persons with subjective symptoms alleged to dental amalgam fillings

This study was carried out to determine whether health disturbances alleged to mercury release from dental amalgam fillings, i.e. "amalgam disease", m ay be caused by an increased sensitivity to mercury (Hg). In the form of a double-blind test, 39 volunteers who themselves suspected "amalgam disease" inhaled small doses of mercury vapour (0.6-10 mu g) or pure air in a rando m sequence. After the induction procedure, the test persons assessed whethe r they reacted or not, i.e. experienced increased illness or not. The test persons also registered the daily intensity of their various symptoms. Calc ulated on the whole population, there was no statistically significant diff erence between the number of reactions after inhalation of mercury vapour c ompared with after inhalation of air. Two subjects, however, reacted signif icantly more often to mercury vapour than to air. The results do not suppor t that short-term exposure to low doses of Hg vapour in general promotes cl inical illness in subjects who themselves suspect "amalgam disease". The de viating reactions presented by two test persons, however, may support the t heory that occasional individuals can be sensitive to very low doses of Hg.