Endodontics is a sub-specialty of dentistry, that deals with the tooth pulp or dentine complex. The most common procedure done in endodontics is root-canal therapy. The pulp (containing nerves, blood and lymph vessels) can become diseased or injured and thus is unable to repair itself. The pulp then dies and Endodontic treatment is required. Endodontic treatment is the removal of diseased pulp tissue. The body's defence system can then repair the damage created by disease. Usually, this will require 2-3 visits to your dentist. The dentist will use a local anaesthetic to make the procedure pain-free. A rubber dam isolates the tooth and provides a clean environment. An opening is made in the top of the tooth then the pulp chamber and root canals are cleaned and shaped for filling and sealing. Between visits, the opening is temporarily filled and removed during the next visit for the next step in the treatment. The tooth will need to be restored, usually by a new crown. If required, a support will be added. Dentists specializing in this field are called endodontists and complete an additional 2-3 years of training following dental school. In the image shown below, if the tooth is treated at stage #1 only a small filling will be required. If decay reaches stage #3, root canal therapy will be required. The aim of treatment is to remove infection (e.g. bacteria) from inside the tooth. If left, the infection would leak out of the tooth's root ends and make the surrounding bone ill and painful.