Case Report: Endodontic management of a fused maxillary lateral incisor and canine with split.

Background: Dental fusion, characterized by the joining of two neighboring tooth germs during odontogenesis, is an uncommon condition affecting approximately 0.1% of the permanent dentition. The unusual anatomy of the pulp chamber and the unpredictable root canal system pose significant challenges during endodontic treatment. Case report: A 47-year-old female patient presented with a 6-month history of spontaneous nocturnal pain in the upper left anterior region. Clinical examination revealed a solitary tooth occupying the positions of teeth 22 and 23; the tooth had a buccal groove and severe distoproximal decay, with no tooth 23. Two pulp chambers joining into one canal in the middle third of the root and a distal periapical radiolucency were found on periapical radiography and cone beam computed tomography imaging. Management: Root canal treatment was performed using nickel-titanium rotary instrumentation with activated irrigation and warm vertical obturation, followed by a split porcelain-fused-metal crown. Conclusion: At the 6-month follow-up, the tooth was asymptomatic tooth with improving periapical condition, thus proving that the interdisciplinary approach guided by imaging provides predictable results in the treatment of permanently fused teeth.