The dental amalgam controversy refers to the conflicting views over the use of amalgam as a filling material mainly because it contains the element mercury. The concern centers on the health effects of toxicity or allergy which may be associated with constant mercury exposure, particularly as an alleged cause of chronic illnesses, autoimmune disorders, neurodegenerative diseases, birth defects, oral lesions, and mental disorders. Scientists agree that dental amalgam fillings leach mercury into the mouth, but studies vary widely in the amount and whether such amount presents significant health risks. Estimations run from 1-3 µg/day (FDA) up to 27 µg/day (Patterson). The effects of that amount of exposure is also disputed, and currently dental amalgam is approved for use in most countries, although Norway, Denmark and Sweden are notable exceptions.
Dentists who advocate the use of amalgam point out that it is durable, cheap, and easy to use. On average, resin composites last only half as long as dental amalgam, although more recent studies find them comparable to amalgam in durability, and dental porcelain is much more expensive. However, the gap between amalgam and composites may be closing. Further, concerns have been raised about the endocrine disrupting (in particular, estrogen-mimicking) effects of plastic chemicals such as Bisphenol A used in composite resins.
In addition to health and ethics issues, opponents to dental amalgam fillings point to the negative externalities of water contamination and environmental damage of mercury. This concern is especially worrisome since its use and disposal by dentists goes largely unregulated in many places, including the United States. The WHO reports that mercury from amalgam and laboratory devices accounts for 53% of total mercury emissions. Separators may dramatically decrease the release of mercury into the public sewer system, where dental amalgams contribute one-third of the mercury waste, but they are not required by some states in the United States.
Dental amalgam tooth fillings do not adversely affect children's brain development and neurological status, researchers report in the February issue of The Journal of the American Dental Association.
The authors of the report--members of a joint team from the University of Lisbon, Portugal, and the University of Washington, Seattle--studied the possible neurological effects of dental amalgam tooth restorations. Dental amalgam contains elemental mercury combined with other metals such as silver, copper, tin and zinc to form a safe, stable alloy. Dental amalgam has been used for generations to fill decayed teeth that might otherwise have been lost.
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