Root canal treatment, also referred to as root canal therapy or endodontic therapy, is used to save an infected or damaged tooth before removal becomes necessary. A root canal is needed when a neglected cavity reaches all the way to the pulp at the center of the tooth, causing the pulp to become infected. Regular cleanings and checkups detect and prevent problems early on.
Trauma can also cause deep damage to the nerve of a tooth. Once this occurs, the pulp becomes infected and begins to eat away at the surrounding bone (this is called an abscess). By the time the pulp is infected it must be treated and cannot heal on its own. It can even weaken the entire immune system, making it very dangerous and painful.
Symptoms of infected pulp may include sensitivity to hot/cold or sweets, pain, swelling, pain with biting or pressure, and a bad taste in the mouth. Sometimes, however, there are no symptoms, and you are unaware of any problem until a checkup.
A root canal is performed to clean out the infected tooth pulp and disinfect the canals of the tooth. The only other treatment would be to extract the tooth. Once the infection is resolved, the canal(s) is filled to prevent any further infection. Crowns are usually recommended to cover and restore a tooth after root canal therapy.