People with high mercury uptake from their own dental amalgam fillings

To describe people with high mercury (Hg) uptake from their amalgam fillings, and to estimate the possible fraction of the occupationally unexposed Swedish population with high excretion of urinary Hg.

Three case reports are presented. The distribution of excretion of urinary Hg in the general population was examined in pooled data from several sources.

The three cases excreted 23-60 micrograms of Hg/day (25-54 micrograms/g creatinine), indicating daily uptake of Hg as high as 100 micrograms. Blood Hg was 12-23 micrograms/l, which is five to 10 times the average in the general population. No other sources of exposure were found, and removal of the amalgam fillings resulted in normal Hg concentrations. Chewing gum and bruxism were the probable reasons for the increased Hg uptake. Extrapolations from data on urinary Hg in the general population indicate that the number of people with urinary excretion of > or = 50 micrograms/g creatinine could in fact be larger than the number of workers with equivalent exposure from occupational sources.

Although the average daily Hg uptake from dental amalgam fillings is low, there is a considerable variation between people; certain people have a high mercury uptake from their amalgam fillings.