Endodontics is a form of dentistry concerned primarily with the roots and soft matter below the tooth. Root canals are required when the pulpy portion of the tooth in the roots become diseased. The surface of the tooth may still be healthy, but the roots are no longer so. The dentist specializing in endodontics extracts diseased pulp from below the tooth by drilling through the tooth.
If only one root is affected, a dentist may do a root canal. However, if more than one root requires cleaning out and pulp extraction, the endodontist, may be called in to perform what will be a longer and more complicated root canal. It can sometimes be difficult to wait for an endodontist, since death or infection of the pulp is usually quite painful. Most endodontists put a temporary filling in the hollowed out roots. Teeth that require a root canal then usually require a crown.