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"Dental Amalgam Fillings" is the Number One Source of Mercury in People and
Exposure Exceeds Government Health Standards for Inorganic Mercury (Vapor)
Government agencies and medical studies have found that the largest source of mercury in most people who have several dental amalgam fillings is from amalgam fillings (ref 2-20, 26, 27). Exposure from fillings amounts to from 50 to 90 percent of exposure, with the average being about 80% of total exposure (5-9, 12-15, 19, 20, 26, 27). The studies found that mercury amalgams are unstable due to mercury's low vapor pressure and galvanic action (24), leaking mercury vapor continuously into the lungs and saliva at levels exceeding health standards. The amount of mercury released by a gold alloy bridge over amalgam over a 10 year period was measured to be approx. 101 milligrams (mg) (60% of total) or 30 micrograms (μg) per day (21b), and other studies have found similar results for amalgam fillings (21a, 12, 18, etc.).
Mercury exposure of most people with fillings was found to exceed government health standards and levels found to cause adverse health effects (see below).
The tolerable daily exposure level for mercury developed in a report for Health Canada is .014 micrograms/kilogram body weight (μg/kg) or approximately 1 μg/day for average adult (2) (.04 μg/day for a 6.5 pound infant or .14 μg/day for a 22 pound infant).
The U.S. EPA Health Standard for elemental mercury exposure (vapor) is 0.3 micrograms per cubic meter of air (1). The U.S. ATSDR health standard (MRL) for mercury vapor is 0.2 μg/m3 of air, and the MRL for methyl mercury is 0.3 μg/kg body weight/day (4). For the average adult breathing 20 m3 of air per day, this amounts to an exposure of 4 or 6 μg/day for the 2 elemental mercury standards. For an infant breathing 4 m3 of air per day, this would be 0.8 to 1.2 μg/day and for a child breathing 8 m3 per day of air this would be 1.6 to 2.4 μg/day.
The EPA health guideline for methyl mercury is 0.1 μg/kg body weight per day or 6 μg to 8 μg per day for the average adult (1). This corresponds to a level of 1 μg/gram in hair which is the EPA reference level for mercury hair test. (this amounts to 0.3 μg/day for a 6.6 pound infant and 1 microgram per day for a 22 pound child)
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 500 μg/day in gum chewers or people who grind their teeth (6, 11, 16, 17, 18) or some with large numbers of fillings. The average amount absorbed was above 10 μg/day (ref. 3-18). The average mercury exposure for a Canadian adult with amalgam fillings was found in the Health Canada study to be 9 μg/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 μg/day and over 50% of all those with 6 or more amalgam fillings had daily exposure exceeding the EPA health guideline (6).
Note that the amount of mercury excreted in feces, as opposed to absorbed, is much higher than most of these estimates of mercury absorbed by the body. Daily excretion through feces amounted to from 30 to 190 μg of mercury, being more variable than other paths (7). Other studies had similar findings (9, 12, 17-19). Most with several amalgams had daily fecal excretion levels over 50 μg/day. The reference average level of mercury in feces (dry weight) for those tested at Doctors Data Lab with amalgam fillings is .26 mg/kg, compared to the reference average level for those without amalgam fillings of .02 mg/kg (27). (13 times that of the population w/o amalgam). Other labs found similar results (27). This level of mercury gives a daily excretion of over 30 micrograms per day. There is also evidence that amalgam is also the largest source of methyl mercury in most people with amalgam, based on studies and medical lab tests of those who have amalgam replaced (26, 27, 12). Mercury vapor and inorganic mercury have been documented to be methylated to methyl mercury by mouth and intestinal bacteria, along with candida albicans and other methyl donars (28), so that even people who don't eat fish but do have several amalgam fillings have high levels of methyl mercury in saliva and blood.
Studies have consistently found modern high copper non gamma-two amalgams have greater release of mercury vapor than conventional silver amalgams (21-23, 25). 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, 6). Due to such widespread high exposures the average person with several amalgam fillings has approx. 10 times higher mercury exposure than those without amalgam (1b), and excretes approx. 30 micrograms into the sewer each day, making dental amalgam the largest source of mercury in sewers. The high levels in sewers and sewer sludge result in amalgam being a significant source of mercury in water bodies and fish, and also a significant source of air emissions from out gassing sewer sludge and crematoria (1c).
Common levels found in persons with amalgam fillings are over 10 times the Health Canada TDE, and more than the EPA health standard for mercury vapor. Thus persons with amalgam fillings have levels of intraoral mercury vapor 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 Organzation 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), 1999, "Integrated Risk Information System", National Center for Environmental Assessment, Cincinnati, Ohio. www.asmalldoseof.org/toxicology/mercury.php & (b) Review of Exposure Research, DAMS International www.flcv.com/damspr1.html ; & Environmental Effects of Amalgam Fillings, DAMS Intl, www.flcv.com/damspr2f.html
(2) Mark Richardson, Environmental Health Directorate, Health Canada, Assessment of Mercury Exposure and Risks from Dental Amalgam, 1995, Final Report.
(3) World Health Organization (WHO), 1991, Environmental Health criteria 118, Inorganic Mercury, WHO, Geneva;
(4) Agency for Toxic Substances and Disease Registry, U.S. Public Health Service, "Toxicological Profile for Mercury", March, 1999; & Jan 2003 Media Advisory, New MRLs for toxic substances, MRL: elemental mercury vapor/inhalation/chronic & MRL: methyl mercury/ oral/acute; & www.atsdr.cdc.gov/mrls/index.html
(5) A. Kingman et al, National Institute of Dental Research, "Mercury concentrations in urine and blood associated with amalgam exposure in the U.S. military population", Dent Res, 1998, 77(3):461-71.
(6) Kraub P., Deyhle M., Maier K.H., Roller H.D., "Field Study on the mercury content of saliva", Heavy Metal Bull, vol.3, issue 1, April '96; & Dr. P. Kraub & M. Deyhle, Universitat Tubingen - Institut fur Organische Chemie, "Field Study on the Mercury Content of Saliva", 1997 (20,000 people tested for mercury level in saliva and health status/symptoms compiled) http://www.uni-tuebingen.de/KRAUSS/amalgam.html;
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(11) L. Barregard et al, "People with high mercury uptake from their own dental amalgam fillings", Occup Envir Med, 1995, 52:124-128.
(12) L. Bjorkman et al, "Mercury in saliva and feces after removal of amalgam fillings", Toxicol Appl Pharmacol 1997, 144 (1): 156-162.
(13) Berglund A., Molin M., "Mercury levels in plasma and urine after removal of all amalgam restorations: the effect of using rubber dams", Dent Mater 1997 Sep;13 (5):297-304;& M.Molin et al, "kinetics of mercury in blood and urine after mercury removal" J Dent Research, 1995, 74:420-
(15) J. Begerow et al, "Long Term Mercury Excretion in Urine after Removal of Amalgam Fillings", Int Arch Occup Health, 1994, 66: 209-212.
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(17) I. Skare, "Mass Balance and Systemic Uptake of Mercury Released from Dental Fillings", Water, Air, and Soil Pollution, 80 (1-4):59-67, 1995.
(18) B. Windham, Anotated Bibliography: Exposure and Health Effects from Amalgam Fillings, 2000 (over 800 references & 60,000 clinical replacement cases).
(19) Sandborgh-Englund G., Elinder C.G., Langworth S., Schutz A., Ekstrand J. "Mercury in biological fluids after amalgam removal". J. Dent Res. 1998 Apr; 77 (4): 615-24.
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(21) (a) J. Pleva, "Mercury-A Public Health Hazard", Reviews on Environmental Health, 1994, 10:1-27, & J. Of Orthomol. Medicine 1989, 4:141- 148; & (b) Jackson G.H., Safety and Review Board of North Carolina, "Quantitative analysis of Hg, Ag, Sn, Cu, Zn and trace elements in amalgam removed from an abutment tooth underneath a gol alloy bridge that had been in vivo for nine plus years", www.ibiblio.org/amalgam/
(22) C. Toomvali, "Studies of mercury vapor emission from different dental amalgam alloys", LIU-IFM-Kemi-EX 150, 1988; & A. Berglund,"A study of the release of mercury vapor from different types of amalgam alloys", J. Dent Res, 1993, 72: 939-946; & D.B. Boyer, "Mercury vaporization from corroded dental amalgam" Dental Materials, 1988, 4:89-93; & V.Psarras et al, "Mercury vapour releases from dental amalgams", Swed Dent J, 1994, 18:15-23; & L.E. Moberg, "Long term corrosion studies of amalgams and Casting alloys in contact", Acta Odontal Scand 1985, 43:163-177;
(23) H. Lichtenberg, "Mercury vapor in the oral cavity in relation to the number of amalgam fillings and chronic mercury poisoning", Journal of Orthomolecular Medicine, 1996, 11:2, 87-94.
(24) Momoi Y., et al; "Measurement of glavanic current and electrical potential in extracted human teeth", J. Dent Res, 65 (12): 1441-1444; & Holland R.I., "Galvanic currents between gold and amalgam". Scand J Dent Res, 1980, 88:269-72; & Wang Chen C.P. and Greener E.H., "A galvanic study of different amalgams", Journal of Oral Rehabilitation, 1977, 4:23-7; & Lemons J.E. et al, "Interoral corosion resulting from coupling dental implants and restorative metallic systems", Implant Dent, 1992, 1 (2):107-112.
(25) P.E. Schneider et al, "Mercury release from Dispersalloy amalgam", IADR Abstrats, #630, 1982; & N. Sarkar, "Amalgamtion reaction of Dispersalloy Reexamined", IADR Abstracts #217, 1991; & N.K. Sarkar et al, IADR Abstracts # 895, 1976; & R.S. Mateer et al, IADR Abstracts #240, 1977; & N.K. Sarkar et al, IADR Abstracts, #358, 1978; & N.W. Rupp et al, IADR Abstracts # 356, 1979; & Kedici S.P.; Aksut A.A.; Kilicarslan M.A.; Bayramoglu G; Gokdemir K. Corrosion behaviour of dental metals and alloys in different media. J. Oral Rehabil 1998 Oct;25 (10):800-8
(26) Leistevuo J. et al, "Dental amalgam fillings and the amount of organic mercury in human saliva". Caries Res 2001 May-Jun; 35 (3):163-6;
(27) Doctors Data Inc.; Fecal Elements Test; P.O.Box 111, West Chicago, Illinois, 60186-0111; http://www.doctorsdata.com/repository.asp?id=43 ; & Biospectron Lab, LMI, Lennart Mansson International AB, lmi.analyslab@swipnet.se (Medical Labs)
(28) Heintze et al,"Methylation of Mercury from dental amalgam and mercuric chloride by oral Streptococci". Scan. J. Dent. Res. 1983, 91:150-152; & L.I. Liang et al, "Mercury reactions in the human mouth with dental amalgams" Water, Air, and Soil pollution, 80:103-107.
(29) GreenPeace/Environmental Quality Institute National Mercury Hair Test Survey, http://www.greenpeace.org/usa/press-center/releases2/twenty-one-percent-of-women-te. Accompanying data tables by State and Metropolitan Statistical Area http://www.greenpeace.org/usa/assets/binaries/addendum-to-mercury-report