Endodontics is a special branch of dentistry that involves the tooth pulp and all of the tissues that surround the roots of the teeth. Tooth pulp is at the center of each tooth where there is a hollow area. The pulp connects to the root of the tooth. It does so with canals, between one and four canals.
The tooth pulp is what is responsible for the health of the tooth. It has the blood vessels and nerves in it, which can become damaged or diseased. If this happens, the pulp can die, which then causes the tooth to require endodontic treatment.