Blood mercury following DMPS administration to subjects with and without dental amalgam.

The use of DMPS as a diagnostic tool in patients with symptoms allegedly caused by mercury from dental amalgam fillings is disputed. We have previously shown that the mercury concentrations in urine cannot be used in such a way. In the present study, we wished to evaluate the effect on blood mercury levels (B-Hg) following intravenously injected DMPS in four groups of subjects: 19 controls without amalgam experience; 21 healthy controls with amalgam fillings; 20 patients with self-reported symptoms from existing dental amalgams; and 20 patients who had removed amalgam fillings. A single dose of DMPS (2 mg/kg) was injected. Blood samples were collected prior to the injection and after 15, 30, 120 min, and after 24 h, and mercury was analyzed by cold vapor atomic absorption spectrophotometry. All groups showed an initial drop of 24 to 30% in the blood levels, approaching baseline values (2.5-5.5 microg/l) after 2 h. The subjects with no amalgam experience had the lowest mercury values. There was no significant difference between the three groups with such experience. There were no significant differences between the two groups with amalgam fillings present. Patients with symptoms allegedly caused by amalgam were not different from the control groups. There were indications that part of the urinary mercury excreted during the first 30 min originated from blood.