The presence of an abscess or infection or detected in the mouth or radiographically usually indicates the need for root canal therapy. A root canal is performed in order to repair and save a traumatized, decayed, broken or infected tooth. The procedure includes the removal of the infected pulpal tissue by cleaning and re-shaping the pulp chambers. After the removal of the infected tissue, the pulpal chamber is filled . In some cases, a metal or plastic rod may be placed in the canal to ensure support of the restoration . The crown of the tooth is then restored to reinforce strength and stability.