When most of us went to the dentist as children and were told we had a cavity, we usually ended up with a silver amalgam filling. There has been a lot of debate over the past few years about amalgam fillings, because they contain mercury. Mercury is a known neurotoxin and poison. Amalgam fillings containing mercury release minute amounts of vapor into the oral cavity. The American Dental Association says that amalgam fillings are considered safe, based on recommendations from the National Institutes of Health, the U.S. Public Health Service, and the World Health Organization.
Despite these assurances, scientists tell us amalgam fillings contain about 40% to 50% mercury. For over a century, medical experts believed that this amalgam was inert. Now, those against the use of amalgam fillings point out that an average filling contains an estimated 800 milligrams of amalgam, with the average middle-aged adult having eight fillings. The average North American adult has 3.2 grams of potential mercury vapor to go into the lungs, blood, and brain from dental fillings alone.
Some clinical trials have been performed to try to resolve the debate about whether amalgam fillings pose a health risk.
In a recent clinical trial conducted in Germany, researchers took a look at data from a number of autopsy studies. They found that there was two to 12 times more mercury in the body tissues of individuals with dental amalgam. They reported that the autopsy studies show consistently that many individuals with amalgam have toxic levels of mercury in their brains or kidneys and that the half-life of mercury in the brain can last from several years to decades. They concluded that mercury vapor is about 10 times more toxic than lead on human neurons and combines with other metals to create new toxic compounds.
In another exhaustive study done at the Umea University in Sweden, researchers found that the daily absorbed dose from amalgam fillings for the average individual is quite low. The researchers believe that this low dose is unlikely to be a health hazard. They mention that those who have a large number of teeth with amalgam fillings and who chew gum constantly will be exposed to a higher dose of mercury. They conclude the study by saying that it is impossible to prove that any restorative material used for fillings is completely safe.
For now, it would seem that the evidence is that amalgam fillings are safe. If you are concerned about mercury levels in your body, talk to your dentist. If you have to have a cavity filled, here’s some health advice: consider getting a composite filling. That way, if clinical evidence does prove in the end that mercury in fillings is harmful, you’ll have one less to worry about.