Root canal help

About 20 months ago I had my teeth cleaned (right after I gave birth to twins) and they noticed a cavity on the top right side.  The dentist fixed it, no problem.  Right away I started to have problems with the tooth and it became infected.  I went back to him and he said I needed a root canal- I had the root canal completed and everything went fine.  I had the temp. crown put in, we waited to make sure there were no more problems and then finally the final crown was placed in place about 3 weeks ago.  It took so long because I wanted to make sure everything was okay in between each step.  Anyway, the tooth started to bother me again about 10 days ago.  The dentist made some adjustments to the crown and it felt much better.  Then, all of a sudden, about 3 days ago I noticed the same tooth has a little swelling in the gums and it looks like there is one small white "bubble."  How could this be infected again?  There is no pain in the tooth at all.  Am I going to need this tooth pulled?  How painful is that?  I am so scared!

[Jerome Tsang, DDS]

The root canal may have failed.  You may need to see the dentist again and get it evaluated.  A re-treatment of the root canal may be necessary.

[erikin]

What is the procedure for a root canal re-treatment?

[jcblandino84]

removal of the gutapercha... re cleaning and re shaping of canals. and filling them up again