Revised: April 2007
Dental amalgam (silver filling) is considered a safe, affordable and durable material that has been used to restore the teeth of more than 100 million Americans. It contains a mixture of metals such as silver, copper and tin, in addition to mercury, which binds these components into a hard, stable and safe substance. Dental amalgam has been studied and reviewed extensively, and has established a record of safety and effectiveness.
Issued in late 1997, the FDI World Dental Federation and the World Health Organization consensus statement on dental amalgami stated, "No controlled studies have been published demonstrating systemic adverse effects from amalgam restorations." The document also states that, aside from rare instances of local side effects of allergic reactions, "the small amount of mercury released from amalgam restorations, especially during placement and removal, has not been shown to cause any … adverse health effects."
The ADA’s Council on Scientific Affairs’ 1998ii report on its review of the recent scientific literature on amalgam states: "The Council concludes that, based on available scientific information, amalgam continues to be a safe and effective restorative material." The Council’s report also states, "There currently appears to be no justification for discontinuing the use of dental amalgam."
In an articleiii published in the February 1999 issue of the Journal of the American Dental Association, researchers report finding "no significant association of Alzheimer’s Disease with the number, surface area or history of having dental amalgam restorations" and "no statistically significant differences in brain mercury levels between subjects with Alzheimer’s Disease and control subjects."
In 2002, the U.S.Food and Drug Administration (FDA) and other organizations of the U.S. Public Health Service (USPHS) that continue to investigate the safety of dental amalgams released a consumer update stating that there is “no valid scientific evidence has shown that amalgams cause harm to patients with dental restorations, except in the rare case of allergy.”
A 2003 paper published in the New England Journal of Medicineiv states, “Patients who have questions about the potential relation between mercury and degenerative diseases can be assured that the available evidence shows no connection.”
In 2004, an expert panel reviewed the peer-reviewed, scientific literature published from 1996 to December 2003 on potential adverse human health effects caused by dental amalgam and published a report. The review was conducted by the Life Sciences Research Office (LSRO) and funded by the National Institutes of Dental and Craniofacial Research, National Institutes of Health and the Centers for Devices and Radiological Health, U.S.Food and Drug Administration (FDA). The resulting report states that, “The current data are insufficient to support an association between mercury release from dental amalgam and the various complaints that have been attributed to this restoration material. These complaints are broad and nonspecific compared to the well-defined set of effects that have been documented for occupational and accidental elemental mercury exposures. Individuals with dental amalgam-attributed complaints had neither elevated urinary mercury nor increased prevalence of hypersensitivity to dental amalgam or mercury when compared with controls.” The full report is available from LSRO (www.lsro.org). A summary of the review is published in Toxicological Reviewsv.
In 2006, the Journal of the American Medical Association (JAMA) and Environmental Health Perspectives published the results of two independent clinical trials designed to examine the effects of mercury release from amalgam on the central and peripheral nervous systems and kidney function. The authors concluded that “there were no statistically significant differences in adverse neuropsychological or renal effects observed over the 5-year period in children whose caries are restored using dental amalgam or composite materials”;vi,vii and “children who received dental restorative treatment with amalgam did not, on average, have statistically significant differences in neurobehavioral assessments or in nerve conduction velocity when compared with children who received resin composite materials without amalgam. These finding, combined with the trend of higher treatment need later among those receiving composite, suggest that amalgam should remain a viable dental restorative option for children.”viii
The ADA supports ongoing research in the development of new materials. However, the ADA continues to believe that amalgam is a valuable, viable and safe choice for dental patients.
i.FDI Policy Statement/WHO Consensus Statement on Dental Amalgam . September 1997. (accessed March 8, 2007)
ii. ADA Council on Scientific Affairs. Dental Amalgam: Update on Safety Concerns. J Am Dent Assoc. 1998;129:494-503.
iii. Saxe SR et al. Alzheimer’s disease, dental amalgam and mercury. J Am Dent Assoc. 1999;130:191-9.
iv. Clarkson TW, Magos L, Myers GJ. The toxicology of mercury – Current exposures and clinical manifestations. N Engl J Med. 2003;349:1731-7.
v. Brownawell AM et al. The Potential Adverse Health Effects of Dental Amalgam. Toxicol Rev. 2005;24:1-10.
vi. Bellinger DC, Trachtenberg F, Barregard L, Tavares M, Cernichiari E, Daniel D, McKinlay S. Neuropsychological and Renal Effects of Dental Amalgam in Children: A Randomized Clinical Trial. JAMA 2006;295:1775-83.
vii. Bellinger DC, Daniel D, Trachtenberg F, Tavares M, KcKinlay. Dental Amalgam Restorations and Children’s Neuropsychological Function: The New England Children’s Amalgam Trial. Environ Health Perspect (online 30 October 2006).
viii. DeRouen TA, Martin MD, Leroux BG, Townes BD, Woods JS, Leitao J, Castro-Caldas A, Luis H, Bernardo M, Rosenbaum G, Martins IP. Neurobehavioral Effects of Dental Amalgam in Children: A Randomized Clinical Trial. JAMA 2006;295:1784-92.
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Page Updated: April 06, 2007