Question of the Week
March 4, 2014
Should dental amalgams be removed due to the concern for mercury toxicity?
Mercury is found in the earth’s crust and is ubiquitous in the environment, so most people have small, measurable amounts of mercury that can be detected in their urine, regardless of whether they have mercury containing amalgams. . However, people with mercury containing amalgams often have slightly higher concentrations of mercury in their urine than those without amalgams. Greatest exposure to mercury occurs during the placement or removal of dental restorations. Once the reaction is complete, far less mercury is released. The amount of mercury released varies with the number of restorations, their surface area, mastication, eating habits and tooth brushing habits etc. Dissolution of mercury from the amalgam does occur and mercury is released as metal ions (which passes into oral fluids and ingested) or evaporates as mercury vapor. Mercury vapor in the oral cavity is either exhaled or inhaled into the respiratory system and distributed by blood to the toxicologically sensitive central nervous system and kidneys. It is excreted by the kidney, sweat and saliva. The concentration remains very low and clinically insignificant.
There are concerns with removing amalgams. One is that the mercury in the amalgams becomes more available for absorption into the body during the removal process. Another is that unnecessary removal of the amalgams subjects the person to risks associated with the procedure, such as those from anesthesia, and to the high costs associated with the procedure. And although dental amalgam removal does lead to reduced mercury concentrations in blood and urine, no differences have been observed in organ function or significant effect on general health. There is lack of evidence of improved health outcomes following removal of dental amalgam fillings.
It is important to remember that whatever the substance, development of poisoning depends on the dose to which one is exposed. In the case of mercury, the amount to which a person is exposed simply from having dental amalgams is just not enough to produce harm. The best thing to do is just leave them alone, unless there is another reason for having the amalgams removed.
The American College of Medical Toxicology has issued a recommendation/commentary based on review of scientific evidence which states: Don’t remove mercury-containing dental amalgams.
This question prepared by: Donna Seger, MD Medical Toxicologist