From the St. Louis Post-Dispatch on mercury in dental fillings:
...Mercury in its many forms is poisonous, especially to children and pregnant women. The most heinous problems are neurological ones, which can hurt children's ability to learn, even before they're born. [...] many dentists and all of the associations that back them say the fillings are safe. But some medical practitioners, holistic adherents and even the World Health Organization say mercury shouldn't be considered totally safe under any conditions.
Here's the best part:
The answer as to whether you should fear your silver fillings falls to your own comfort level, dentists say.
A health study at the National Institute of Environmental Health Sciences (NIEHS) finds that certain deodorising products including air fresheners, toilet-bowl cleaners, and mothballs may be harmful for your lungs.
"Because people spend so much time indoors where these products are used, it's important that we understand the effects that even low levels might have on the respiratory system," said researcher Leslie Elliott.