I need a root canal on an infected tooth

[tlcha]

I had a crown that got a hole in it and caused infection, this was 1.5 years ago. My dentist put a crown on back then. Now the same tooth is causing me awlful pain and my dentist says I need root canal. Why would he ever put a crown on a tooth that had an infection. I was treated with antibiotics and I am being treated again 1.5 years later with antibiotics because of that same infection. I think he should have done a root canal then. I have had so many health problems since then I think it's from a tooth that never completely got rid of infection, otherwise I wouldn't need root canal. I just hope the ttoth is worth saving to go through all this. I feel like having it pulled out but can't stand the thought of being toothless.It is a molar tooth.
I am suppose to have a root canal 3 days after being on this antibiotic. Is 3 days enough time on an antibiotic for infection in tooth before having root canal?

[scottma]

Seeing an endodontist to have root canal treatment as soon as possible is advised.

[blackfang]

I have an infection in a tooth that was root canalled many years ago.  I have an infection being treated with Clindamycin  The tooth is upper right molar #3.  If a re-root canal cannot be done, I'd rather not have an apico done, in order to be able to have a better chance of bone for an implant.  I will be seeing my endodontist on Monday.  I assume that I am running out of options for this tooth??