Root canal treatment (also referred to as endodontic therapy) may be necessary to save a tooth for a number of reasons: When a cavity reaches all the way to the pulp or nerve of the tooth and causes an infection. The infection can extend through the root and into the bone causing an abscess. Deep restorations or trauma to a tooth may also cause the nerve to be damaged to the point it needs a root canal.
Root canal treatment cleans out the infected pulp tissue and disinfects the canals. Once the infection is resolved, the canal(s) are filled in attempt to prevent any further infection. A core build-up and crown is recommended for restoring a tooth that has had root canal therapy.