The above question is a very common, and entirely understandable, one that patients ask when root filled teeth are still giving them problems. The simple answer is -“the tooth may be dead, but you are not”!
The tenderness they feel is coming from inflamed tissue surrounding the tips of the roots, all of which is still very much alive. The inflammation is caused buy bacteria within the canals, which generate a response from the bodies immune system. This response is to send extra blood supply to the area to try and fight the infection, which in turn causes extra fluid to be forced in to the tissues, which we feels as tender swelling. If the bacterial load gets high enough and the bodies response angry enough we develop all the familiar symptoms of an acute swelling – pain, heat, redness, swelling and not forgetting, PAIN!. A lot of the time, fortunately, the response is less dramatic and is a chronic, low grade grumble that never quite goes away. Often patients, and even dentists, will feel that there is nothing more to be done but to take the tooth out but this is a shame because modern endodontics (root fillings) can often win where previous root fillings have failed.
This case is an example of modern endodontics being used to prolong the useful life of a tooth. The tooth in question had the original root filling done 2 years ago and never felt right since it was completed. The dentist at the time made every effort to do the work well but unfortunately did not use a surgical microscope and fine ultrasonic tips so was unable to see and treat the full anatomy of the pulp chamber. As is often the case this left some unexplored canal anatomy that housed sufficient infected debris to cause recurrent infection, which the patient felt as tenderness around the tooth and discomfort on chewing.
Once the tooth was fully explored and disinfected these symptoms settled within 48 hours. Because the tooth was very heavily filled and had developed decay under the old filling the decision was made to prepare the tooth for a cast restoration immediately, rather than wait a few months to see if the second root filling had been successful. It is always tricky to decide when to place an overlay but on this occasion it was felt that the greater risk to the tooth was fracture rather than reinfection.