Amalgam, an alloy of mercury, has been used for over 150 years in dentistry due to its low cost, durability and strength. Amalgam consists of a mixture of mercury, zinc, tin, copper and silver. There has been public concern that the mercury could pose a risk of toxicity in humans with amalgam dental work.
Multiple studies have been done to assess the possible toxicity of dental amalgam and its relation, if any, to mercury toxicity. A study in New Zealand from 1977-1997 of 20,000 patients did not find any association between dental amalgams and chronic fatigue syndrome or chronic kidney disease. Another study in which patients believed their amalgams were making them chronically ill showed that there was no association between measured mercury levels in these patients and their symptoms.
Rarely, some patients can have allergic reactions to mercury. Dental amalgams have been shown to be associated with allergic reactions to mercury. These reactions can consist of white spots in the mouth, skin rashes on the head and neck area, and mild lip swelling. These symptoms typically resolve on their own within a few days of the amalgams being placed, but in rare instances have required removal of the dental implants for resolution of symptoms. Allergy to mercury is quite rare, and reactions typically are limited to skin rashes.
A comprehensive review article published in 2012 evaluating all available studies on the risk of dental amalgams in humans concluded that the current use of dental amalgams did not pose a health risk to humans, except for those who suffered allergic reactions. Additionally, there is not sufficient evidence to justify removal of existing amalgam dental work in patients. Lastly, the authors concluded that there is no evidence that mercury released from amalgams results in adverse health effects in the general population.
In conclusion, multiple large studies have not shown any evidence that mercury released from amalgams results in adverse health effects or human toxicity. Although rarely some people may have allergic reactions to the mercury-containing dental amalgams, there is no evidence to support the removal of these amalgams, or to ban their use in dentistry. Additionally, due to the results of these many studies, the American College of Medical Toxicology included the recommendation not to remove dental amalgams in the Choosing Wisely Campaign. Individuals with dental amalgams are not at higher risk of mercury toxicity, and there is no evidence of a link between dental amalgams and mercury toxicity.
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