I'm Having Tooth Ache Previous Year And Doctor Had Made

i'm having tooth ache previous year and doctor had made root canal and kept cap on the tooth and after six months the pain started severely and I went to the same doctor and he removed the cap and drilled it again. and after several months I got pain for the same tooth and simultaneously one more tooth is getting severe pain and I consulted the doctor and again he is saying we will do root canal.. now the technology had changed and there will be no problem in the future with this treatment as you had earlier. The tooth which is paining is very strong and the doctor is telling to drill it for root canal.

I'm getting afraid whether this tooth also become as that of previous one if the root canal is done..

what should I do now . Can you suggest me on this please ?