How can a dentist tell whether you need a root canal?

X-rays, symptoms +: X-rays often show decay which violates the integrity of the nerve of the tooth, or the presence of an infection in the bone. Certain clinical symptoms such as severe throbbing pain, or pain to hot which is relieved by cold are classical symptoms suggesting the need for rct. Finally, actually seeing decay down to and exposing the nerve of the tooth is justification for rct.

Several Indicators: Many symptoms can indicate a tooth needs a root canal. Among these are swelling around a tooth, radiographic indication of abscess tissue, tenderness of the tooth to percussion, throbbing pain, very extreme heat/cold sensitivity.

Pulp Testing: A dentist or root canal specialist will test your tooth/teeth and see if you have abnormal results in one tooth. You may have something visible on a xray or large decay inside your tooth. You may have severe response to temperature or no response to temperature. You may have sensitivity to biting and pressure on the tooth or the surrounding gum. You may have swelling. Testing will tell.