How do you determine that a tooth needs a root canal?

After examination and x-ray films, your dentist will let you know if you are a good candidate for a root canal. Depending on your age, health status, etc. Most likely happens when the nerve of the tooth is decaying or becomes infected. you will be on antibiotics for a while until the infection clears. Then depending on above mentioned, it may take a few visits to complete the procedure. The first visit will be the touchiest of most. I'm not going to lie to you, it is painful even with anesthetic. However, after the main root is out, some teeth have several roots and canals. The next 2 or 3 visits should go well. Be patient with the appointments this procedure cannot be rushed. I am 66 and all my life have heard "Horror" stories about the pain associated with Root Canal procedures. About 5 years ago I had to have one in a molar, and I am here to tell you that there was NO more pain involved than occurs during the injection of the local anesthetic!!!!! After the local anesthetic "wore off," there was no actual pain, only about 24 hours of a sensation of "pressure."I have since discussed this with a couple of dentists and have been told that most of the rumors of extreme pain with root canals is exaggeration.