Autogenous Transplantation of an Immature Undersized Third Molar to Rehabilitate a Cyst-associated Lateral Incisor Defect: A 3-Year Case Report.

Severe periapical cysts frequently result in tooth loss with concomitant severe alveolar bone destruction, precluding immediate implant placement. Autogenous tooth transplantation, which involves transplanting the patient's own tooth to the recipient site, offers a biological approach to reconstruct both the dentition and supporting bone structures. This report presents a 25-year-old female with a mobile, discolored maxillary right lateral incisor (#12) exhibiting grade 3 mobility due to a large periapical cyst (extending to #14 on cone-beam computed tomography) with root developmental arrest, secondary to Oehlers type II dens invaginatus. Autogenous transplantation was performed using an immature impacted third molar (#28) with compatible root morphology. Despite pulp necrosis requiring root canal treatment at 1 month, functional stability was achieved by 3 months. Three-year follow-up demonstrated complete bone healing, intact periodontal ligament space, and absence of resorption or ankylosis on cone-beam computed tomography. This case underscores the promising role of autogenous tooth transplantation as a viable treatment option for complex dental scenarios.