I have been greatly benefited by the discussion on this thread so far. Root canal is out of question now.
2 follow up questions:
(1) Ozone therapy (to sterilize decayed tooth) and do temporary filling and some supplementation to re-mineralize infected tooth: In the long run does it work or this itself becomes source of infection?
(2) Zirconium implant (if decide to extract the decayed tooth): Do they too become source of mild infection in the long run?
Hopefully I'm not too insistent on dental issues, somehow preliminary discussion with 2 biological dentists brought these (these dentists are new to me therefore a bit hesitant to trust everything they say), however I would like to take independent decision based on what is "right" as learned from this thread/forum so far.