Amalgam: Statements of Support

September 3, 2002

Agency for Toxic Substances and Disease Registry

Removal of dental amalgams in people who have no indication of adverse effects is not recommended and can put the person at greater risk, if performed improperly. [Public Health Statement for Mercury. March 1999]

Alzheimer’s Association

In 1991, the U.S. National Institutes of Health (NIH) funded a study at the University of Kentucky to investigate the relationship between amalgam fillings and Alzheimer’s disease. The study, a collaboration involving the university’s Sanders-Brown Center on Aging and the College of Dentistry, enrolled hundreds of participants from central Kentucky as well as some from Wisconsin. . . .

The amalgam study research team obtained an extremely detailed dental history documenting how many fillings each participant had, where in the mouth the fillings were located, how long the fillings had been present, and how much surface area they covered. Participants also agreed to have their brains autopsied to confirm their Alzheimer diagnosis or lack of brain pathology and to measure levels of mercury in their brain tissue. Over the length of the study, the researchers collected data from 68 individuals with Alzheimer’s and 33 without the disease who met all study criteria. Data analysis by University of Kentucky statisticians revealed no significant association between Alzheimer’s disease and any aspect of silver fillings — their number, location, duration, or surface area. Furthermore, brain tissue samples revealed no correlation between Alzheimer’s disease and brain levels of mercury. The researchers analyzed the tissue samples with a highly sensitive technique capable of detecting extremely low levels of mercury. [The results of the study were published in Saxe SR and others. Alzheimer’s disease, dental amalgam, and mercury. Journal of the American Dental Association 130:191-199, 1999.]

Many scientists consider this study compelling evidence that dental amalgam is not a major risk factor for Alzheimer’s disease. Public health agencies — including the FDA, the U.S. Public Health Service, and the World Health Organization — endorse the continued use of amalgam as a safe, strong, inexpensive material for dental restorations. [Q&A about dental fillings and Alzheimer’s disease. Alzheimer’s Association fact sheet, October 2001]

American Academy of Pediatrics

Although dental amalgams are a source of mercury exposure and are associated with slightly higher urinary mercury excretion, there is no scientific evidence of any measurable clinical toxic effects other than rare hypersensitivity reactions. An expert panel for the National Institutes of Health has concluded that existing evidence indicates dental amalgams do not pose a health risk and should not be replaced merely to decrease mercury exposure. [Goldman LR, Shannon MW. Technical report: Mercury in the environment: implications for pediatricians. Pediatrics 108:197-205, 2001]

Autism Society of America

Although a single specific cause of autism is not known, current research links autism to biological or neurological differences in the brain. In many families there appears to be a pattern of autism or related disabilities — which suggests there is a genetic basis to the disorder — although at this time no gene has been directly linked to autism. The genetic basis is believed by researchers to be highly complex, probably involving several genes in combination. [What is autism. Autism Society of America, 2002]

National Multiple Sclerosis Society

While the cause of MS remains unknown, there is no evidence that heavy metal poisoning is responsible. There have been some claims that mercury leaking from amalgam dental fillings damages the immune system, and causes a broad range of diseases, including MS, by contributing to the demyelinating process. A demyelination process destroys the myelin sheath that surrounds and protects nerve fibers.

There is no scientific evidence to connect the development of MS with dental fillings containing mercury. Although poisoning with heavy metals — such as mercury, lead, or manganese — can damage the nervous system and produce symptoms such as tremor and weakness, the damage is inflicted in a different way and the course of the disorder is also different. [The MS Information Sourcebook, 2001]

New England Journal of Medicine Editorial

In the assessment of patients with possible mercury exposure, the three key determinants of clinical toxicity are the form of mercury, the route of exposure and the dose. Unfortunately, it is often very difficult for both laypeople and health care providers to understand these essential distinctions. Despite the lack of scientific evidence, claims have been made that the mercury in dental amalgams is responsible for such disorders as coronary artery disease and multiple sclerosis. Thousands of people have had their dental fillings removed out of fear of mercury toxicity. After an exhaustive investigation and review of the evidence, including the form of mercury in question, the route of exposure, and the dose, the Public Health Service concluded that dental amalgams do not pose a serious health risk. [Kulag K. A tragic reminder about organic mercury. New England Journal of Medicine 338: 1692-1693, 1998]

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This page was revised on September 3, 2002.