Success in pulp revascularization after autotransplantation tends to happen in a tooth with an incomplete root formation, while a tooth with a complete root formation needs a root canal treatment. However, recent studies
showed that apicoectomy facilitated the repair and revascularization process with promising outcomes. This study aimed to compare the incidences of pulp necrosis and root resorption of autotransplanted teeth with a complete root formation which underwent apicoectomy and teeth with an incomplete root formation. Patients with a history of autotransplantation received clinical and radiographic follow-up examination. The autotransplanted teeth were divided into two groups, the incomplete root formation group and the extraoral apicoectomized complete root formation group. Pulp and periradicular outcomes (pulp healing, pulp necrosis and presence of root resorption) were determined with an additional of cone-beam computed tomography investigation. The incidence of each outcome and prognostic factors were statistically compared. The result showed that the incomplete root formation group presented 40 % (4 of 10) pulp necrosis and 10 % (1 of 10) root resorption, while the extraoral apicoectomized complete root formation group presented 77.8 % (7 of 9) pulp necrosis and 66.7 % (6 of 9) root resorption. The periradicular status between the two groups was significantly different. No prognostic factor was found to be related to pulp outcome, however apicoectomy and recipient socket were found to be related to the periradicular outcome. Autotransplanted teeth with complete root formation undergoing extraoral apicoectomy increased the risk of pulp necrosis and root resorption. A totally prepared recipient socket without remaining periodontal ligament was also found to be related to root resorption.