The influence of dental amalgam placement on mercury, selenium, and glutathione peroxidase in man

Amalgam restorations were inserted in eight healthy persons, previously unprovided with dental restorations, who had several severe carious lesions. The mean number of surfaces restored were 16.1 (range, 11 to 22). The total mean calculated amount of mercury inserted was 2.9 g (range, 1.5 to 4.3 g). Blood and urinary levels were measured on seven occasions during a 4-month period before and a 3-month period after amalgam placement. One and 3 months after placement, the P-mercury mean values were almost equal to the preplacement values (3.3 nmol/l). After placement U-mercury increased continuously; 3 months after placement a statistically significantly higher (p less than 0.05) mean U-mercury value (0.58 nmol/mmol creatinine) was found compared with the mean preplacement value (0.34 nmol/mmol creatinine). No statistically significant correlation was found between the P- and U-mercury concentrations and the total number of amalgam surfaces. Selenium levels in plasma and urine and erythrocyte glutathione peroxidase showed no systematic change of pattern. The results show that the insertion of amalgam fillings contributed to the U-mercury concentration, but apparently even more extensive amalgam therapy and/or longer exposure periods are needed to affect the P-mercury concentration. No negative effects on the P- and U-selenium or the erythrocyte glutathione peroxidase levels could be found during the 3 months immediately after an extensive amalgam placement. The supplementary blood and urine analyses were not influenced by the insertion of amalgam fillings.