Silver concentrations in human tissues. their dependence on dental amalgam and other factors

Human tissue samples (liver, kidney cortex, 5 brain regions: grey matter of cerebrum, white matter of cerebrum, nucleus lentiformis, cerebellum, brain stem) from 173 decreased persons were analysed for silver (Ag) by GF-AAS (Graphite Furnace Atomic Absorption Spectrometry) and the results compared with the number of teeth with amalgam fillings and the concentration of inorganic mercury (Hg), which had been determined in the same tissue samples in a previous study. It was found that the mean Ag concentrations in liver and brain of adult females are approximately twice that of males. Moreover, the Ag concentrations, especially in the brain, depend possibly on age. To exclude these confounding factors as far as possible, the influence of dental amalgam and the correlation of Ag and Hg were evaluated only in a sub-group of 93 males, aged 11-50 years. In this sub-group statistically significant correlations were found between the number of teeth with dental amalgam and the Ag concentrations in the cerebral cortex and the liver. No such correlation was found for the kidney. Ag and inorg. Hg correlate well in this sub-group in the liver, but not in the cerebral cortex or the kidney. Individuals from this sub-group with (i) 0-2 and with (ii) more than 9 teeth with amalgam fillings show mean Ag concentrations (micrograms/kg in tissue wet weight, geom. mean) of 1.59 and 5.41 in the grey matter of cerebrum, 1.42 and 4.25 in the white matter of cerebrum, 1.53 and 4.89 in the nucleus lentiformis, 1.95 and 5.02 in the cerebellum, 1.05 and 3.27 in the brain stem, 3.40 and 8.15 in the liver and 0.42 and 0.44 in the kidney cortex. In contrast, comparing all individuals under investigation with only 0-2 teeth with amalgam no correlation between Ag and inorg. Hg could be found in liver, kidney cortex or cerebral cortex. These results show that amalgam fillings release Ag as well. Considering the different toxicokinetics of Ag and Hg it can be concluded that Ag is a reliable marker for the fact that the elevated concentrations of inorg. Hg found in tissues of individuals with amalgam fillings derive mainly from these fillings and not from other theoretically possible sources.