Root migration after coronectomy of impacted mandibular third molars: case reports

Coronectomy is recommended for third molars that require extraction and are located near the inferior alveolar nerve (IAN) or the mandibular base. The procedure is aimed at reducing the risk of complications, but root migration is among the possible sequelae of this surgical technique. This report describes 3 clinical cases of root migration after coronectomy of impacted mandibular third molars. All 3 cases involved women aged 21 to 31 years and followed the surgical principles recommended for the technique: local anesthesia, periodontal ligament detachment, pericoronal ostectomy, sectioning of the dental crown, and crown removal with complete elimination of enamel from the roots, which remain impacted below 3 mm of bone. The patients were followed up with clinical and imaging examinations for 1 year. Panoramic radiographs at 1 year revealed root migration of 3 to 5 mm. None of the patients opted for removal of the residual root fragments because they were not causing any pain. Root migration after coronectomy cannot be perceived as a failure of this relatively safe alternative to extracting mandibular third molars near the IAN because the root always moves away from the nerve and usually causes no additional symptoms. Secondary surgery to remove the residual root should only be performed if migration results in root exposure, pain, or infection.