The most common complaint that brings the patient to the dental office is pain or discomfort. Besides pain, signs to look for include prolonged sensitivity to heat or cold, discoloration of the tooth, and swelling and tenderness in the nearby gums. Sometimes the tooth becomes sensitive to chewing or to tapping. A tooth that becomes badly decayed or injured may need treatment.

The dentist will do a series of test to isolate the offending tooth. Occasionally a x-ray will show evidence of an abscess at the end of an infected tooth. Results of these tests will indicate whether or not an endodontic procedure is necessary.

A common belief is that by removing the nerve the tooth becomes "dead". This is not true. The tooth may no longer be vital but is very much alive and functioning because it receives a source of blood supply and nerve supply from the surrounding tissues that hold it in place in your jaw bone. The tooth will have no sense of feeling to hot, cold, or sweets but will be responsive to biting pressure etc. With proper restoration the tooth should last as long as your other teeth and can even be used as a anchor tooth for a partial denture or cemented bridge. The success rates for root canal therapy have been reported to be as high as 95 percent.