Fredin B.

Studies on the Mercury Release from Dental Amalgam Fillings.

Swed J Biol Med no 3, 1988 pp 8-15.


ABSTRACT:
"Several aspects of Hg release from dental Amalgam tooth fillings were examined both in vivo and in vitro. By light microscopy Hg globules (diameter = 1-2 um) were observed on Amalgam surfaces. Hg vapor was measured in exhaled air before and after 5 minutes of gum chewing in 3 groups of subjects with varying numbers of dental Amalgams (Group 1: having symptoms similar to chronic low dose Hg exposure, N=22; Group 2: having no apparent symptoms and considered healthy, N=20; Group 3: controls having no amalgam fillings; N=10).

Groups 1 and 2 both demonstrated a significant 3-fold increase in Hg vapor levels after chewing, while levels in controls remained undetectable. A mouth rinse of hot water (55¡C) in Group 2 resulted in a further increase in Hg vapor levels.

Saliva samples (1 ml) from 17 subjects in group 2, collected before and after chewing, showed a significant 8-fold increase in Hg concentrations after chewing. In a fourth group Hg absorption by the oral mucosa was studied, Group 4, N=10, A notably high absorption was found after 3 minutes.

It is concluded that dental amalgam should be considered an unstable alloy constituting a long term Hg exposure and toxicologically unsuitable as a dental filling material."