Inside each tooth is the pulp which provides nutrients and nerves to the tooth. It runs like a thread down through the root. When the pulp is diseased or injured, usually due to decay or trauma, the pulp tissue dies. . The medical name for a root canal treatment is endodontics and is usually abbreviated to RCT. If the pulp becomes infected the infection may spread through the root canal system of the tooth and this could lead to an abscess.  If this occurs and a root canal treatment is not carried out, the infection will spread and the tooth may need to be extracted. In root canal treatment, the pulp is removed and the root canal is cleaned and sealed off. A filling or crown is then placed on top of the tooth to protect it.