http://www.mercola.com/2001/may/19/amalgam.htm

*An excerpt from:

Dentists Sue Over Gag Order on Silver Amalgam Fillings
At issue are those silver-colored fillings that dot most people's teeth.
Referred to by the dental profession as silver amalgam, the fillings are
actually about half mercury, with some silver, copper, tin and zinc mixed
in.

Mercury opponents argue that mercury vapor coming from the fillings seeps
into the body, contributing to a range of health problems from fatigue and
immunity suppression to neurological diseases such as Parkinson's and
Alzheimer's.