Tooth germ autotransplantation of open apices of the teeth exhibits high pulpal healing rates, whereas that of mature permanent teeth normally causes irreversible pulpal necrosis. Extraoral root-end resection (EORER) during transplantation may promote pulpal revascularization (PRV) in transplanted mature teeth and reduce endodontic treatment requirement. This study compared the primary outcomes of survival rates, PRV, and root resorption and determined relevant confounders in autotransplanted mature and immature teeth. The medical charts of consecutive patients who underwent tooth autotransplantation between January 2017 and March 2021 were evaluated. Teeth with a documented follow-up of at least 1 year were included. During the study period, 59 teeth were transplanted in 44 patients. Overall, 2 teeth were excluded owing to missing data; 57 teeth were analyzed, including 25 mature teeth additionally treated with EORER. After a mean follow-up of 21.2 ± 16.1 months, no significant differences in primary outcomes were detected. Fifty-five teeth remained in situ (96.5%), and radiological signs of root resorption were detected in 9/57 teeth (15.8%). PRV was positive in 54/57 teeth (94.7%). Surgical duration and PRV failure were significantly associated with high incidences of root resorption. Mature teeth autotransplantation with EORER yielded similar results to immature teeth autotransplantation and is a feasible treatment option. Long surgery and failed revascularization increased root resorption rates. More factors should be evaluated in larger trials with longer observation periods.