Patient-friendly definition from the DentistsDirectory.org dental glossary.
Endodontics is the dental specialty concerned with the biology, diagnosis, and treatment of the dental pulp and the tissues surrounding tooth roots. "Endo" means inside, and "odont" means tooth — endodontists work on the inner architecture of the tooth. An endodontist completes two to three additional years of advanced specialty training after dental school, focusing on root canal procedures, dental pain diagnosis, and the management of dental trauma.
Root canal treatment is the most common endodontic procedure, but endodontists also perform: endodontic retreatment (reopening and retreating a previously root-canalled tooth when infection persists); apicoectomy (surgical removal of a root tip to treat a persistent periapical infection); treatment of cracked teeth; tooth replantation after traumatic avulsion; and management of complex dental pain that is difficult to diagnose. Their advanced training gives them expertise in highly precise procedures on teeth with complex canal anatomies.
Many general dentists perform root canals on front teeth and premolars. Endodontist referral is typically recommended for: root canals on molars (which have multiple, often curved canals that are technically demanding); cases where previous root canal treatment has failed; teeth with calcified canals; severe dental infections; cracked teeth; and complex pain cases that have been difficult to diagnose. If your general dentist refers you to an endodontist, it usually means the case has a level of complexity where the specialist's skills improve the chances of saving the tooth.