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The Dangers of Dental Amalgam Fillings

by Bernie Windham(more info)

listed in dentistry, originally published in issue 45 - October 1999

Government agencies and medical studies have found that the number one source of mercury in people is dental amalgam fillings.[2-20] Exposure from fillings amounts to from 50 to 90 percent of exposure, with the average being about 80 per cent of total exposure.[5-9],[12-15],[19],[20] The studies found that mercury amalgams are unstable due to mercury's low vapour pressure and galvanic action, leaking mercury vapour continuously into the lungs and saliva at levels exceeding health standards.

Mercury exposure of most people with fillings was found to exceed government health standards and levels found to cause adverse health effects.

The US EPA mercury health standard1 for elemental mercury exposure (vapour) is 0.3 micrograms per cubic meter of air (0.3 ug/M3). For the average adult breathing 20 m3 of air per day,[2] this amounts to an exposure of 6 micrograms (mg) per day. The corresponding tolerable daily exposure developed in a report for the Canadian Health Agency, Health Canada, is .014 mg/kg body weight or 1 mg/day for an average adult.[2] The U.S. Agency for Toxic Substances and Disease Registry (ASTDR) standard (MRL) for acute inhalation exposure to mercury vapour is 0.02 micrograms Hg/m3, which translates to approx. 1.2 mg/day for the average adult.

The range of mercury exposure levels found in people with amalgam fillings by the World Health Organization Scientific Panel on Mercury was 3 to 70 micrograms per day,[3] with other medical studies finding up to 200 mg/day in gum chewers or people who grind their teeth.[6],[11],[16],[17],[18] The average exposure was above 10 mg/day.[3-18] The average mercury exposure for a Canadian adult with amalgam fillings was found in the Health Canada study to be 9 mg/day.[2] In a large German study with 20,000 tested subjects at a University Medical Clinic, the average exposure from fillings was over 10 mg/day and over 50% of all those with 6 or more amalgam fillings had daily exposure exceeding the EPA health guideline.[17]

Studies have consistently found modern high copper non gamma-two amalgams have greater release of mercury vapour than conventional silver amalgams.[21],[22],[23] Recent studies have concluded that because of the high mercury release levels of modern amalgams, mercury poisoning from amalgam fillings is widespread throughout the population.[17],[22],[18]

Common levels found in persons with amalgam fillings are over 10 times the Health Canada limit, and more than the EPA health standard for mercury vapour. Thus persons with amalgam fillings have levels of intraoral mercury vapour and body exposure levels higher than the level considered to have significant health risk.

The studies found that total mercury intake is proportional to the number and extent of amalgam surfaces, but other factors such as chewing gum and drinking hot liquids influence the intake significantly increasing exposure as much as 500%.

A World Health Organization Scientific Panel concluded that a safe level of mercury exposure below which no adverse effects occur has never been established.[3]


1 U.S. Environmental Protection Agency (EPA), Integrated Risk Information System, National Center for Environmental Assessment, Cincinnati, Ohio, 1996 (& web).
2 Richardson, Mark. Environmental Health Directorate, Health Canada, Assessment of Mercury Exposure and Risks from Dental Amalgam, Final Report 1995; & Richardson G.M. et al. A Monte Carlo Assessment of Mercury Exposure and Risks from Dental Amalgam, Human and Ecological Risk Assessment, 2(4): 709-761, 1995.
3 World Health Organization (WHO), Inorganic Mercury, Environmental Health criteria 118 WHO, Geneva, 1991; & Craelium W. J Epidemiology and Community Health, 32: 155-65, 1978.
4 Agency for Toxic Substances and Disease Registry, U.S. Public Health Service, Toxicological Profile for Mercury, ATSDR TP93/10, 1994.
5 Skare I. Mass Balance and Systemic Uptake of Mercury Released from Dental Fillings, Water, Air, and Soil Pollution, 80(1-4): 59-67, 1995.
6 Skare I. et al. Human Exposure to Hg and Ag Released from Dental Amalgam Restorations, Archives of Environmental Health 49(5): 384-394, 1994.
7 Weiner J.A. et al. The relationship between mercury concentration in human organs and predictor variables, 138(1-3): 101-115,1993; & An estimation of the uptake of mercury from amalgam fillings, Sci Total Environment, 168(3), 1995.
8 Lussi A. Mercury release from amalgam into saliva, Schweiz Monatsschrahnmed, 103(6): 722-6, 1993.
9 Vimy M.J. and Lorscheider F.L. Faculty of Medicine, Univ. Of Calgary, July 1991. (Study findings) & J. Trace Elem. Exper. Med., 3, 111-123, 1990.
10 Gay D.D. et al. 1979, Lancet, May 5, 1985; & Svare C.W. et al. The effects of amalgams on mercury levels in expired air, J Dent Res, 60, p1668, 1981.
11 Barregard L. et al. People with high mercury uptake from their own dental amalgam fillings, Occup Envir Med, 52: 124-128, 1995.
12 Bjorkman L. et al. Mercury in saliva and feces after removal of amalgam fillings, Toxicol Appl Pharmacol, 144(1): 156-162, 1997.
13 Molin M. et al. Kinetics of mercury in blood and urine after mercury removal, J Dent Research, 74: 420, 1995.
14 Zander D. et al. Mercury Concentration in Urine in Relation to Number of Amalgam Fillings, Zbl Hyg, 190: 325-334, 1990.
15 Begerow J. et al. Long Term Mercury Excretion in Urine after Removal of Amalgam Fillings, Int Arch Occup Health, 66: 209-212, 1994.
16 Sallsten G. et al. Long term use of chewing gum and mercury exposure from dental amalgam, J Dental Research, 75(1): 594-598, 1996.
17 Kraub P. et al. Universität Tubingen, Institut für Organische Chemie, 1997, & Gerhard I., Roller E., et al. Tubingen Univ. Gynecological Clinic, Heidelberg, 1996, BUND Press Release 1997 & Bundesinstitut fur Arzneimittel un Medizinprodukte, 1997.
18 Windham B. Annotated Bibliography of Exposure and Health Effects from Amalgam Fillings, 1997 (over 400 references).
19 Halbach. Estimation of mercury dose, Int. Archives of Occupational & Environmental Health, 67: 295-300, 1995; & Sandborgh-Englund G. Pharmacokinetics of mercury from dental amalgam, Gotab (Stockholm), 1-49, 1998.
20 Aposhian H.V. Envir. Health Perspectives, Vol 106, Supp 4, Aug, 1998; & Aposhian H.V. et al. FASEB J, 6: 2472 –2476, 1992.
21 Pleva J. Mercury – A Public Health Hazard, Reviews on Environmental Health, 10: 1-27, 1994.
22 Toomvali C. Studies of mercury vapor emission from different dental amalgam alloys, LIU-IFM-Kemi-EX, 150, 1988; & Berglund A. A study of the release of mercury vapor from different types of amalgam alloys, J Dent Res, 72: 939-946, 1993; & Boyer D.B. Mercury vaporization from corroded dental amalgam, Dental Materials, 4: 89-93, 1988; & V. Psarras et al, Mercury vapour releases from dental amalgams, Swed Dent J, 18: 15-23, 1994; & Moberg L.E. Long term corrosion studies of amalgams and casting alloys in contact, Acta Odontal Scand, 43: 163-177, 1985; & Moberg L.E. Corrosion products from dental alloys, Published Dissertation, Stockholm, 1985.
23 Lichtenberg H. Mercury vapor in the oral cavity in relation to the number of amalgam fillings and chronic mercury poisoning, Journal of Orthomolecular Medicine, 11: 2, 87-94, 1996.


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