From offender to replacement: using the adjacent third molar to rebuild a compromised second molar through autotransplantation

Adjacent third molars can contribute to distal caries and periodontal damage of neighboring second molars. This report describes a 22-year-old woman in whom an immature mandibular right third molar (#48) was autotransplanted to replace a compromised mandibular right second molar (#47). A delayed protocol combined CBCT-based digital planning, a 3D-printed donor replica for guided socket preparation, and concentrated growth factors (CGF) for donor preservation and bioactive socket lining. At 12 months, CBCT showed preserved crestal bone, a continuous lamina dura, and a uniform periodontal ligament space without resorption. A positive electric pulp testing response at 12 months suggested possible neurosensory recovery of the transplanted tooth. In this case, delayed autotransplantation of an immature open-apex mandibular third molar to a previously inflamed second-molar site was followed by an asymptomatic, functional transplant at 12 months, with favorable periodontal and osseous healing and no endodontic or prosthetic intervention. Longer follow-up is required.