All dentists receive basic training in root canal treatment in dental school. However, because endodontic retreatment can be more challenging than providing first-time treatment, many dentists refer patients needing endodontic retreatment to endodontists. Endodontists are dentists with at least two additional years of advanced specialty education in diagnosis and root canal treatment. Because they limit their practices to endodontics, they treat these types of problems every day. Endodontists are experts in performing nonsurgical and surgical retreatment. They use their special training and experience in treating difficult cases, such as teeth with narrow or blocked canals or unusual anatomy. Endodontists may use advanced technology, such as operating microscopes, ultrasonics and digital imaging to perform these special services.