[Mercury determination in human amniotic fluid]

One of the components of Ag amalgam is mercury which, owing to its organic derivatives, can pass into the organs and biological fluids. One particularly interesting but worrying aspect of this transition is the possibility that mercury may pass through the placental barrier and reach the fetus. The aim of this study was to evaluate the concentration of total mercury in human amniotic fluid and compare it with the number and occlusal extension of fillings using Ag amalgam.

A group of 56 pregnant women were selected due to undergo amniocentesis. A dental check-up was carried out in each patient to identify the number and extension of amalgam fillings. Mercury levels in the amniotic liquid were assayed using a spectrophotometer with atomic absorption and a FIAS-amalgam technique.

Mercury concentrations in the samples examined ranged from a minimum of 0.00 ng/ml to a maximum of 2.55 ng/ml, mean 0.44 +/- 0.53 ng/ml. The correlations between the variables examined were evaluated by calculating the coefficient of linear regression. No direct relationship was found with mercury levels. The data obtained were used to construct a model of logistic regression showing scant statistical significance (p = 0.05) between the number of fillings and mercury levels, whereas the occlusal extension of dental repairs was significantly correlated with metal concentrations (p < 0.05).

The authors recommend that silver amalgam should be used with considerable caution during pregnancy.