socasusie: 21 RCs on 15 teeth?? Good grief. I think I'll invest into intradental toothbrush, water flossed and replace old amalgam fillings with ceramic inlays as soon as $$$ permits it and while I'm still young (I'm 35).

Bryanna:
Yup, I don't know about other people, but I certainly received very little info from all the dentists I've had so far, about anything at all. I usually do my own research online, but only when the need arises, and the need usually needs to stem from chronic, not acute health problem (those we forget quickly and rightly so). One year ago my knowledge about teeth was about 1% of what is it now. I've actually started reading "Clinical Endodontics: A Textbook"...

The situation in upper left quadrant seems bad with two adjacent RC'd teeth, but it's good to get to know the options as other RC'd teech are not adjacent to each other. I recently started using a "private" dentist in addition to "public" one (the one provided as part of public healthcare) and this was the first time I learned about options other than amalgam and composite (white) fillings... the inlays, onlays etc. So now I can actually plan a solution that would include removing a RCd tooth, and change the old fillings on adjacent teeth with inlays = inlay bridge.

I guess the long term viability of RC depends on the magnitude of initial infection, quality of performed procedure and person's immune system? So all RC will "fail" eventually (I now often hear from my mother she has "focal infections" visible on panoramic x-ray according to the dentist - I'd bet many of those teeth were root-canaled...), but not necessarily in 5 or 10 years. Age + general health must be a factor too. 5/6 of my root canals were done without any symptoms other than pulpal pain that wouldn't go away after 2 days (irreversible pulpitis), i.e. no abscess or granuloma. Pain was noticable in 3 of them, and 1 was actually done without any pain whatsoever (dentist saw a cavity on x-ray, tried to fix it, discovered the pulp is already irritated and performed a RC right away - I thought what the hell, but maybe that wasn't such a bad decision after all).