Dental amalgam has been used for over 150 years to fill cavities and restore teeth. It is composed of mercury, silver, tin, zinc, and copper. The removal of dental amalgam as treatment is based on the idea that mercury from amalgam is slowly released and causes or exacerbates MS. It is claimed that very small amounts of solid and vaporous mercury are released and, by damaging both the nervous and immune systems, cause MS and other conditions. Furthermore, it has been suggested that diseases can result from allergic reactions – mercury sensitivity, mercury hypersensitivity, mercury toxicity, or micromercurialism – or a small electrical current produced by the mercury –oral galvanism or electrogalvinism.
Before removal, a careful evaluation of the dental work is usually completed. This may include a questionnaire about symptoms, allergy testing, electrical readings of restorations, hair analysis, and mercury-vapor tests. Sometimes a few fillings at a time are removed, a method claimed to release “locked mercury.” After removal, gold or plastic fillings are used for dental work.
Evaluation in MS and Other Conditions
Several claims have implicated dental amalgam as a factor in MS. MS has been associated with dental treatment and the bacterial disease that produces cavities (dental caries). It has also been proposed that MS can be caused by exposure to heavy metals, including mercury.
Dental amalgam has been implicated in the etiology of several other diseases. These include other neurological conditions, including headaches, brain tumors, epilepsy, and Parkinson’s disease. Dental amalgam has also been implicated in other immune-related conditions, such as lupus, arthritis, and chronic fatigue syndrome. It has also been suggested that it is linked to cancer, depression, and heart disease. Mercury toxicity may produce symptoms similar to those MS.
Despite these observations, the available research does not indicate that mercury causes MS nor that amalgam removal is a beneficial treatment for MS. Mercury toxicity and MS share many symptoms, however they are the results of different pathological processes. Also, MS was a recognized disease well before dental amalgam was commonly used, and many people with MS have no dental amalgam.
Dental amalgam does not release high levels of mercury. In order to produce even mild toxic effects, it is estimated that a person would need to have about 200 fillings. Dental amalgam is believed to constitute ten percent or less of total mercury consumption. The rest of the mercury intake comes from fish, other foods, medications, pollution, disinfectants, and paint.
The American Dental Association (ADA) has found unnecessary dental amalgam removal to be an improper and unethical practice. A dentist in Colorado had his licensed revoked for removing dental amalgam from MS patients in 1996. The National Institutes of Health (NIH), the Public Health Service, and the National Multiple Sclerosis Society of the United States also do not support amalgam removal.
Mercury allergies are rare. They have not been linked to other diseases and usually only result in a swelling of the area immediately surrounding the amalgam-filled tooth.
Large-scale clinical studies evaluating dental amalgam removal have not been conducted.
Dental amalgam removal is usually well tolerated. For a brief time following removal, mercury levels in the blood may increase. As with other dental procedures, there is a rare possibility of damaging tooth structures or nerves.
Dental amalgam removal is generally well tolerated, but is relatively expensive. It is hard to definitively determine the amount of risk involved when using compounds like dental amalgam. Rigorous clinical studies in MS are lacking, but from the available evidence it appears that dental amalgam removal is not beneficial for people with MS.
References and Additional Reading
Bowling AC. Complementary and Alternative Medicine and Multiple Sclerosis. New York: Demos Medical Publishing, 2007, pp. 83-86.
Bates MN, Fawcett J, Garrett N, et al. Health effects of dental amalgam exposure: a retrospective cohort study. Int J Epidemiol 2004;33:1–9.
Casetta I, Invernizzi M, Granieri E. Multiple sclerosis and dental amalgam: casecontrol study in Ferrara, Italy. Neuroepidemiology 2001;20:134–137.
Ekstrand J, Bjorkman L, Edlund C, et al. Toxicological aspects on the release and systemic uptake of mercury from dental amalgam. Eur J Oral Sci 1998; 106:678–686.
Eley BM, Cox SW. The release, absorption, and possible health effects of mercury from dental amalgam: a review of recent findings. Brit Dental J 1993; 175:355–362.
Fung YK, Meade AG, Rack EP, et al. Brain mercury in neurodegenerative disorders. J Toxicol Clin Toxicol 1997;35:49–54.
Mackert JR, Berglund A. Mercury exposure from dental amalgam fillings: absorbed dose and the potential for adverse health effects. Crit Rev Oral Biol Med 1997; 8:410–436.
NIH Conference Assessment. Effects and side-effects of dental restorative materials. Adv Dental Res 1992;6:1–144.
Sheridan P. Amalgam restorations and multiple sclerosis. MS Management 1997;4:21–40.