Aim

To describe the clinical, radiographic and histological aspects of the retreatment of a second upper molar in which root perforation had occurred during the original treatment.

Clinical case

A 50-year old male was referred for endodontic retreatment of the right second maxillary molar. Radiographic examination revealed the presence of an incomplete root canal treatment, a radiolucent periapical area and a root perforation produced by a threaded post placed outside of the mesiobuccal root canal. After post removal, the root perforation was sealed with Biodentine and the root canals were retreated.

Two years later, the patient returned to the office complaining of severe pain during mastication, in the area of the previously retreated right second maxillary molar. Clinical and radiographic examination revealed the presence of a vertical fracture on the palatal root. Since this kind of root damage non-restorable, the tooth was extracted and submitted to histologic analysis. The laboratory report revealed that the perforation site had healed by the apposition of new calcified tissue, and that the remnants of periodontal tissue which persisted attached to the root were within normal limits. This clinical case highlights the importance of thorough knowledge of the anatomy of the root canal system in order to avoid procedural errors which may compromise the prognosis of the treatment.