Robert S. Baratz, MD, DDS, PhD
If amalgam waste from dental offices poses an environmental risk, how can amalgam in the mouth be safe?
One really doesn't have much to to with the other.
To properly report a risk, one should include how likely it is to occur. When mixed, the ingredients in amalgam form a solid compound that does not readily come apart. Amalgam can be safely put into landfills and buried because it stays as amalgam. Amalgam scrap that is mishandled can wind up in an incinerator where the extreme heat vaporizes it so that its original ingredients enter the earth's atmosphere.
Amalgam put into teeth stays largely as amalgam. Body temperature is far lower than incinerator temperature. Amalgam doesn't vaporize at body temperature. Trace amounts of mercury can come out when you grind your teeth, mostly from surface wear. These amounts are similar to those found in food, air, and water. They are considered harmless by every responsible health agency that has studied them. The most important consideration in determining the potential effect of any foreign substance introduced into the body is dose. Chewing and grinding can cause amalgam fillings to release tiny amounts of elemental mercury. There is no scientific evidence that this amount (perhaps 1-2 micrograms/day inhaled and 1.5 micrograms/day swallowed) has any adverse health effects. The body deactivates this mercury just as it does the mercury in food, air and water. Eventually it is excreted.
Although mercury from amalgam represents less than 1% of the mercury released into the environment, the dental community has developed safe ways to handle amalgam waste. Since amalgam waste contains considerable silver, it is usually recycled. Its mercury is also recycled. Amalgam waste becomes an environmental problem only if it is mishandled.
This page was posted on November 15, 2004.