root canal tooth still painful

I've had pressure pain in a the last molar on the upper left for over 2 years now, which after much treatment is not getting better. I had it filled 3 times, after which I still kept having mild pain. The dentist put a gold inlay and adjusted the bite, no difference. He couldn't tell anything from the X-Rays, but the pain got worse and I asked him to do a root canal this May. The tooth was all dead. After the root canal, my pain got worse - I had severe response to cold and hot and even to movement. After taking antibiotics and painkillers w/o difference I asked to dentist to re-do it, which he did very reluctantly. He took out the filling of the canal and didn't seal it, because I was about to leave for a couple of months. The throbbing pain was now gone, but I still had pressure pain and occasionally pain that came on its own. There was never any swelling, although the gum area is sensitive to pressure. A month ago the dentist filled the root canal again after draining it and said there was some blood in it. The tooth was painful - i was given anesthesia, and no difference again. I am wondering is it possible that there is a 4th canal and that is causing the problem?  Could redoing the root canal again make a difference?  How long can I wait without doing something?  

[Jerome Bogin, D.D.S.]

There is always the possibility of a fourth or accessory canal. I do not know if the dentist is an endodontist, if not it might be a good idea to see a specialist at this point.If the infection is still present it is only going to get worse so I don't think it would make much sense to wait.

[DentalAssitantRCT]

I have worked for a Endodontist (Root canal specialist) for over 6 years now.  I can tell you there can most likely be a 4th canal in that tooth. Also if you are having sens to hot and cold I would consider it may be another tooth. Once the nerve is removed you shoul not be feeling "hot and cold" in that tooth. I would highly reccomend seeing an Endodontist, as they have an additional 2 years of training for Root Canal procedures and most of them have Dental Microscopes in the office so they can locate 4th canals.

[Killerpain]

I would advise you read about Trigeminal Neuralgia. Some people have unnecessary root canals when it is really a nerve issue.