Root canals are also a serious concern as a breeding ground for bacteria.
The potential health problems that can arise from dental toxicity span a huge range of mental and physical disease. Investigations into these matters are very recent, and hampered by an unwillingness on the part of official dental bodies to acknowledge the problem, for obvious reasons.
Dentists with the skills to remove amalgam filling safely and replace them are rare as yet. Add to this the need to replace root canals with bridges, and your dentist needs to be a believer as well as skilled. In the National Capital Region I am aware of only two practitioner in some of these disciplines: Dr. Ghislain Dessureault, tel 819-770-8315 (Hull, Que) and Dr. Ronald Morin, tel 819-685-9499 (Aylmer, Que).
One conclusion is clear. Avoid amalgam fillings and root canals, particularly if you currently have none. Find out what you can, including from the sources below. You won't find this information in your dentist's office.