Allogenic Tooth Transplantation Using 3D-Printed Donor-Tooth Replicas: A Case Report

Background: Allogenic tooth transplantation has been reported for several decades, but clinical evidence remains limited, particularly regarding contemporary digital workflows, immunological characterization, and long-term outcomes. Cone-beam computed tomography (CBCT), computer-aided design/computer-aided manufacturing (CAD/CAM), and three-dimensional (3D) printing may facilitate preoperative planning and recipient-site preparation while minimizing manipulation of donor teeth. Case Report: A 48-year-old woman underwent allogenic transplantation of two mature maxillary first premolars donated by her 17-year-old son. The corresponding recipient teeth (14 and 24) had been absent for more than 10 years following unsuccessful endodontic treatment. CBCT-based planning and 3D-printed donor-tooth replicas were used to prepare the recipient sites before donor extraction. Owing to anatomical differences in root morphology and recipient-site dimensions, the teeth were transplanted contralaterally (donor 14 to recipient 24 and donor 24 to recipient 14). The extra-alveolar time was approximately 20 s for each tooth. Clinical, periodontal, radiographic, and immunogenetic assessments were performed during postoperative follow-up. Results: At 12 months, both transplanted teeth remained functional without clinically apparent complications. Periodontal probing depths remained unchanged between the 3- and 12-month examinations (tooth 14: 3.5 mm mesially and 4.0 mm distally; tooth 24: 3.0 mm mesially and 3.5 mm distally), with no bleeding on probing and mobility grade 0. No radiographically apparent pathological root resorption or ankylosis was identified. Post-transplant immunogenetic testing demonstrated donor-specific anti-HLA class I and II reactivity. Anti-MICA antibodies were not detected. In the absence of pre-transplant serum, the detected donor-specific antibodies could not be classified as pre-existing or de novo. Conclusions: CBCT-based planning and 3D-printed donor-tooth replicas facilitated the technically feasible transplantation of two mature allogenic premolars, with favorable short-term clinical findings at 12 months. Despite this clinical stability, donor-directed anti-HLA reactivity was detected after transplantation. These findings neither establish immunological tolerance nor demonstrate that the observed alloimmune reactivity was induced by transplantation. Longer follow-up and prospective immunological monitoring are required to evaluate graft survival and the clinical significance of donor-specific antibodies.