I actually fell victim of this when as a child i had some teeth filled with amalgam. I was often very sick, stomach aching, head aching. Thankfully my mother read up on the topic early and about 20 years ago had all of the stuff re-extracted from my teeth and substituted with ceramics. My issues are gone ever since. But still today, i talk to dentists who claim this is a made up issue. It's terrifying.
RE: Must Read Before Your Next Dentist Visit: Is Your Dentist Poisoning You?