Endodontics is a branch of dentistry recognized by the American Dental Association involving treatment of the pulp (root canal) and surrounding tissues of the tooth. The word "endodontic" comes from "endo" meaning inside and "odont" meaning tooth. Endodontists are dentists who have specialized in this field. When you look at your tooth in the mirror, what you see is the crown. The rest of the tooth, hidden beneath the gum line, is called the root.