Endodontics is a specialty of dentistry, that deals with the tooth pulp and tissues surrounding the root of a tooth. The pulp (containing nerves, arterioles and venules as well as lymphatic tissue and fibrous tissue) can become diseased or injured and thus is unable to repair itself. The pulp then dies and endodontic treatment is required. The word comes from the Greek words endo meaning inside and odons meaning tooth. Literally taken, it means study of that which is "inside the tooth".
Endodontists are dentists who have specialized in this field. Typically they have completed an additional 2-3 years of training following dental school. Many endodontic residents do original research and earn a Master's degree as well as a specialty certificate. They specialize and limit their practice to root canal therapy and root canal surgery. Patients requiring root canal therapy are either referred by their general dentists to the endodontist or are self referred. Root canal therapy is also a standard procedure for general dentists.
The most common procedure done in endodontics is root-canal therapy. This procedure aims to save a tooth that would otherwise be extracted (pulled) due to infection caused by decay (a cavity in the tooth), a large filling, or trauma to the tooth. Root canal therapy involves the removal of diseased pulp tissue inside the tooth (the area inside the tooth that becomes infected due to the aforementioned reasons). The aim of treatment is to remove irreversibly inflamed, or necrotic pulp tissue before infection sets in (or after it has already set in). When the pulp tissue becomes infected, caused by bacteria from inside the tooth, the infection can leak out of the tooth's root and make the surrounding bone ill and painful or cause an abscess to form. Once the diseased pulp tissues are removed, the body's defense 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 anesthetic to make the procedure pain-free. In most places, it is considered a standard of care to use a rubber dam in order to isolate the tooth and provide a clean environment. An opening is made on the top of the tooth. Then the pulp chamber and root canals are cleaned and shaped for filling and sealing. Often, an intra-pulpal medicament to inhibit bacterial growth is placed and the tooth is filled with a temporary restoration until the second appointment, where the temporary restoration and medicament are removed and the canal(s) are sealed with gutta-percha--thus completing the procedure. Increasingly, however, endodontic treatment is being performed in one appointment as clinicians are finding fewer incidents of infection and pain with one-appointment vs. two appointment treatment.