Endodontists are dentists who specialize in maintaining teeth through endodontic therapy -- procedures, involving the soft inner tissue of the teeth, called the pulp. The word "endodontic" comes from "endo" meaning inside and "odont" meaning tooth. Like many medical terms, it's Greek.
All dentists are trained in diagnosis and endodontic therapy, however, some teeth can be especially difficult to diagnose and treat. That’s why you may have been referred to an endodontic specialist.
In addition to dental school, endodontists receive two or more years of advanced education in this kind of treatment. They study root canal techniques and procedures in greater depth, for diagnosis and treatment of more difficult cases. For this reason, many dentists choose to refer their patients to endodontists.