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“The concentrations of 17 elements in the hair and nails of 180 Alzheimer’s disease (AD) and control subjects have been determined by instrumental neutron activation analysis (INAA). Comparisons of trace element levels of properly matched AD and control groups revealed significant imbalances in the concentrations of six elements (Br, Ca, Co, Hg, K, and Zn) between disease and control groups. It is noteworthy that each of these has previously been shown by our group, or others, to be altered in some AD brain region(s). Geometric means for each element in both hair and nails of AD and control subjects are presented, and significant differences noted. The significance of these alterations with regard to the possible role of trace elements in the etiology of AD is discussed.”

“Stock’s (1939) findings that amalgam fillings could release mercury vapor created an intense debate. The question was discussed again as a result of Frykholm’s studies in the 1950s (Frykholm, 1957). By using radio-active mercury he showed that insertion of amalgam in humans could give rise to a considerable uptake of mercury as indicated by high concentrations in urine and feces. Dental amalgams once more have become of interest as a source of mercury vapor exposure to the general public (Enwonwu, 1987).”

“In the ANPRM for mercury-containing drug products for OTC topical antimicrobial use (47 FR 436, January 5, 1982), the Advisory Review Panel on OTC Miscellaneous External Drug Products placed all mercury compounds in Category II for topical antimicrobial use. This included the following ingredients: Ammoniated mercury; calomel (mercurous chloride); merbromin (mercurochrome); mercuric chloride (bichloride of mercury, mercury chloride); mercufenol chloride (ortho-chloromercuriphenol, ortho-hydroxyphenylmercuric chloride); mercuric salicylate; mercuric sulfide (red mercuric sulfide); mercuric oxide, yellow; mercury; mercury chloride; mercury oleate; nitromersol; para-chloromercuriphenol; phenylmercuric nitrate; thimerosal; vitromersol; and zyloxin.”

“The cytotoxic action (CTA) of chemical substances contained as admixtures in medical immunobiological preparations on human diploid cells has been studied. Such chemical substances as rivanol and merthiolate in admissible concentrations show the highest degree of CTA. The results obtained in this investigation indicate that different concentrations of chemical substances may produce equal CTA; thus, thiolate in toxic in a dose of 0.8 microgram/ml; the same CTA is produced by aluminium sulfate in a concentration of 500 micrograms/ml. Small doses of chemical substances, producing no explicit manifestations of the cytotoxic effect, may have latent CTA determined by additional methods of investigation. CTA may be manifested as lethal, sublethal and latent cell lesions. In working out regulations on the test for CTA it is expedient to indicate admissible residual amounts of chemical substances contained in finished medical immunobiological preparations, considering that these amounts must be incapable of producing CTA in cell cultures. The conclusion has been made on the expediency of denoting small amounts of chemical substances capable of producing latent CTA as tentatively tolerable doses.”

“A study of 162 dentists’ and their assistants’ mercury levels in hair and urine, and of questionnaire items regarding mercury consumption, revealed some striking relations. The mercury concentrations in both hair (Hg-H) and urine (Hg-U) were somewhat higher in the dentists than the assistants. There was no relation between concentrations in hair and urine. The method of condensation of amalgam was positively related to Hg-U; the vibration method was negatively related. Hg-U was also positively related to number of fillings and hours in own practice. The relation of Hg-U to ventilation in the surgery applied only to the dentists.”

“Eighty-one women (45 dentists and 36 dental assistants) occupationally exposed to metallic mercury underwent a toxicoclinical examination. Total mercury lebels (TMLs) were determined in scalp and pubic hair by cold vapour AAS. Furthermore a detailed questionnaire study was made concerning adverse reproductive events. TMLs in the hair of the exposed women examined exceeded significantly those determined in the hair of 34 controls not exposed to mercury. All exposed women had continued working during pregnancy. There was a significant, positive association between TMLs in the hair of exposed women and the occurrence of reproductive failures in their history. The relation between TMLs in the scalp hair and the prevalence of menstrual cycle disorders was statistically significant. These findings indicate that dental work could be another occupational hazard with respect to reproductive processes.”

“Data from this project demonstrate a positive correlation between the number of occlusal surfaces of dental amalgam and mercury levels in the brain (p less than .0025 in white matter). This is indirect evidence suggesting that mercury from dental amalgam fillings may contribute to the body burden of mercury in the brain. The toxic levels of mercury in human tissues have not been sufficiently investigated and the amount of mercury in human brain tissue from dental amalgam may or may not be clinically significant. Nevertheless, dental amalgam exposure should be considered in monitoring sources of mercury accumulation in human brain tissue.”

For approximately 150 years, mercury in amalgam has been used as a dental restorative material. Throughout this time the potential toxicity of this metal to patients (1-5) and dental professionals (4-9) has been studied and debated. In these reports and many others, problems with mercury contamination and toxicity were uncovered. Although the extent of the problems may be controversial, the overall impact has led to increased emphasis on mercury hygiene in dental schools and in private practice (10-11).”

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