Post Root Canal Infection

I had a root canal several years ago on a fractured tooth, when the dentist did the root canal he said that the canals were completely dry and that the tooth was necrotic.  It felt great after the root canal, but a few weeks later it got sensitive and a little swollen and red on the gums between the teeth.  After I got the crown, it did feel like the fracture was better but it didn't solve the problem.  I moved to a new city and my new  dentist changed the neighboring crown, which also didn't solve the problem.  This swelling and sensitivity to heat just keeps coming back and the dentist keeps telling me to brush and floss my teeth better and prescribed me a rinse.  I always brush and floss my teeth, so it seemed strange.  He also told me that everyone has bacteria and it's nothing to worry about, but it causes me great discomfort and has for several years.  Any suggestions?  

[Jerome Bogin, D.D.S.]

I am not sure if the symptoms are coming from the gum in that area or the tooth that has had the root canal. The sensitivity to heat is more likely a tooth problem and not the gum tissue.I am not sure what type of swelling you are describing. I would suggest that you see a root canal specialist(endodontist) to rule out a recurrent infection from the old rct.