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“Using an interdisciplinary approach, the current position in the dental amalgam controversy and the potential impact of amalgam mercury on human health are reviewed. Aspects of materials science, corrosion, mercury exposure, toxicology, neurology and immunology are included. New data on mercury exposure from corroded amalgam fillings in vivo are presented. The exposure can reach levels considerably over known threshold limit values. Also, measurements of mercury absorption from intraoral air are presented. The vital importance of avoiding a galvanic amalgam-gold coupling is emphasized. The symptomatology of a disabled patient, who recovered after amalgam removal, has been included. It is concluded that discussion of the dental amalgam issue has suffered from the lack of an interdisciplinary approach. It would be wise to learn from the lesson of acrodynia, and consider amalgam mercury among other possible factors in neurological and immunological diseases of unclear etiology.”

“Urinary mercury (U-Hg) and plasma mercury (P-Hg) levels were higher in 244 dental personnel than in 81 matched referents (U-Hg: 1.8 and 1.1 mumol/mol creatinine, respectively; p less than .001; P-Hg: 6.7 and 6.2 nmol/l, respectively; p = .03). The amalgam in the mouth influenced mercury levels in whole blood (B-Hg), plasma, and urine. The association was nonlinear: the more amalgam, the larger the relative increase in mercury levels. The number of amalgam surfaces accounted for more of the variance in blood and urine mercury levels than did the number of fillings (e.g., U-Hg: 44% and 36%, respectively). The estimated increases in mercury level with rising amalgam load were 3.0%, 2.0%, and 0.8% per filled surface for U-Hg, P-Hg, and B-Hg, respectively (p less than .0001 in all cases). The impact of occupational exposure on U-Hg in the dental personnel corresponded to approximately 19 amalgam surfaces. Ceramo metallic restorations were associated with higher (31%) U-Hg.”

“These data raise serious doubts abour the reliability of statements from the Canadian and American Dental Associations. Experiments in primates clearly demonstrate that Hg [mercury] released from ‘silver’ tooth fillings concentrates in body tissues in amounts sufficient to alter cell function.'”

“Individuals who are xenobiotically sensitive to chemicals comprise a living indicator system that enables us to identify that group in the population that is also mercury sensitive. There is a spectrum of xenobiotic intolerance in the general population that is a function of, among other things, the spectrum of efficiency of the cytochrome P-450 system that exists in the population due to a spectrum of genetic polymorphism. Dental mercury inactivates those groups, whose function is protection of the cytochrome P-450 system. This inactivation and consequent loss of protection induces xenobiotic intolerance in individuals who are already compromised due to genetic polymorphism and who are the most susceptible individuals in the genetic population to further compromise. These compromised individuals will exhibit a variety of diagnostically confusing heterogenous symptoms. On March 15, 1991, the Food and Drug Administration convened a hearing on the “Potential Toxicity of Dental Amalgam”. I was one of the invited speakers. The following is based on the speech I delivered at that meeting. My purpose in this presentation is to
make three points:
1. Mercury from dental amalgam induces symptoms in a sensitive group of the population that has also been observed to be sensitive to xenobiotic substances. (Xenobiotic substances are substances which are foreign to the natural state of an organism. Examples of such foreign substances are petrochemical vapors, chlorinated hydrocarbons, sulfites, and metals which are not metabolically useful.)
2. This sensitive group serves as a marker that warns of the potential danger of dental mercury to the rest of the population who are also at risk but may not yet exhibit symptoms.
3. Dental mercury should be banned.”

“Saccharomyces cerevisiae and Candida albicans were incubated with 0.25, 0.5, or 0.75 micrograms of Hg (as HgCl2) per ml of Nelson’s medium in the presence of trace amounts of oxygen at 28 degrees C for 12 days. Two control media were used, one without added Hg and one without yeast inoculum. Yeast cell growth was estimated after 1, 2, 3, and 8 days of incubation. The contents of organomercury in the system and of elemental mercury released from the media and collected in traps were determined at the end of the experiments. The results were as follows. (i) C. albicans was the more mercury-resistant species, but both yeast species failed to grow in the media containing 0.75 micrograms of Hg per ml. (ii) The amounts of organomercury produced by the two species were proportional to the amount of HgCl2 added to the medium. In all cases C. albicans produced considerably larger amounts of methylmercury than S. cerevisiae. (iii) The amounts of elemental Hg produced were inversely proportional to the HgCl2 level added in the case of S. cerevisiae but were all similar in the case of C. albicans. (iv) Neither organomercury nor elemental Hg was produced in any of the control media.”

“A WHO Task Group on Environmental Health Criteria for Inorganic Mercury met in Bologna, Italy, at the County Council Headquarters (Provincia) from 25 to 30 September 1989.  The meeting was sponsored by the Italian Ministry of the Environment and organized locally by the Institute of Oncology and Environmental Sciences with the assistance of the County Council…The Task Group reviewed and revised the draft document and made an evaluation of the human health risks from exposure to inorganic mercury.”

“The pathogenesis of Alzheimer’s Disease (AD) is unknown. Using SDS-PAGE and autoradiography the authors’ laboratory has shown: (1) that the tubulin in AD brain is less photolabeled by ({sup 32}P)8N{sub 3}GTP than is tubulin from control brain and (2) that low {mu}M levels of preformed Hg{sup 2+}EDTA specifically blocked interactions of tubulin-({sup 32}P)8N{sub 3}GTP in control human brain homogenates giving a photolabeling profile identical to AD brain. Elevated levels of Hg{sup 2+} have been reported in AD brain by others. Earlier work using ({sup 32}P)8N{sub 3}GTP with Al{sup 3+} treated rat and rabbit brain showed no differences from control with regards to tubulin photolabeling. However, our latest data show that brain samples from Hg{sup 2+} fed rats display an abolished GTP-tubulin interaction similar to AD brain samples as determined by ({sup 32}P)8N{sub 3}GTP photolabeling profiles. Removal of Hg{sup 2+} from treated rats did not reverse the effect. These results suggest that certain complexed forms of Hg{sup 2+} must be considered as a potential source for the etiology of AD.”

“Exposure to mercury contamination in the dental office poses a potential hazard for dental personnel. Although many precautions for containing the poisonous metal vapors are routinely observed, dental personnel may place themselves at risk by failing to use proper cleaning techniques. Researchers from the National Institute for Occupational Safety and Health (NIOSH) have discovered that vacuum cleaners designed for the home are sometimes used to clean dental office carpets, which might be contaminated with mercury. Since ordinary vacuum cleaners increase airborne mercury concentrations, dental personnel should use a specially designed vacuuming system for mercury recovery.”

“In humans Hg vapor is released from “silver” amalgam fillings that contain 50% Hg by weight. Previous studies show that when 12 such fillings are placed in sheep teeth, the kidneys will concentrate amalgam Hg at levels ranging from 5 to 10 micrograms Hg/g renal tissue 4-20 wk after placement. In the present study 12 occlusal fillings were placed in each of six adult female sheep under general anesthesia, using standard dental procedures. Glass ionomer occlusal fillings (12) were inserted in two control sheep. At several days before dental surgery, and at 30 and 60 days after placement of fillings, renal function was evaluated by plasma clearance of inulin and by plasma and urine electrolytes, urea, and proteins. An average plasma inulin clearance rate of 69.5 +/- 7.2 ml/min before amalgam placement was reduced to 32.3 +/- 8.1 ml/min by 30 days and remained low at 27.9 +/- 8.7 ml/min after 60 days. Inulin clearance did not change in controls. After amalgam placement urine concentration of albumin decreased from 93.0 +/- 20.5 to 30.1 +/- 15.3 mg/l and urine Na+ concentration increased steadily from 24.8 +/- 7.7 to 82.2 +/- 20.3 mmol/l at 60 days. Concentrations of K+, urea, gamma-glutamyl transpeptidase, alkaline phosphatase, and total protein did not change significantly from 0 to 60 days in urine. Plasma levels of Na+, K+, urea, and albumin remained unchanged from 0 to 60 days after amalgam. Renal histology remained normal in amalgam-treated animals.” (ABSTRACT TRUNCATED AT 250 WORDS)

“This article gives a toxicological risk analysis of occupational diseases in dentistry that are related to chronic exposure to inorganic mercury, especially metallic mercury vapour. Studies have indicated that dental work involving mercury may be an occupational hazard with respect to reproductive processes, glioblastoma (brain cancer), renal function changes, allergies and immunotoxicological effects. The correlation of chronic exposure to mercury in dentistry to the health situation of dental workers’ health situation needs to be further studied.”