I've been reading with interest this forum, and pardon the pun, it seems most writers here think that root canal is the root of all evil and sickness in the modern world. Most writers here represent an unfortunate grouping of cases where it has gone wrong. In fact, my grandmother lived to be 92 with several root canals, false teeth and whatever, my father is 67 and in excellent health and there is no dental treatment you can think of that he hasn't had, same with my mother and almost everybody I know. There is absolutely no evidence that root canals in themselves cause health problems. Every medical treatment in the book has it's risks. I'm pretty sure that if you checked teenagers with ear infections you'll find out that a large portion of those have had piercing done, so does that mean piercing is evil ? No, it means that in a tiny minority something happened, probably due to poor sanitation.
My guess is that the majority of the cases where it's gone wrong the patients went to regualr dentist instead of specialists.