Tooth transplantation and a root submergence technique after enucleation of multiple continuous radicular cysts for implant treatment: a case report

When a radicular cyst-involved tooth is challenging to save, tooth extraction and cyst enucleation are required. Since only thin facial bone is present on the coronal side of cystic defects, bundle bone loss and continuity of the cystic cavity after tooth extraction may result in extensive vertical bone defects. To prevent major bone augmentation, the following procedure was performed: the left maxillary incisor (#9), which exhibited apical lesions was extracted, while the right maxillary incisor (#8), despite having a healthy periodontal ligament but being difficult to save, was transplanted into the extraction socket of the left incisor (#9). After 5 months, the bone defect had completely regenerated without any resorption of the facial bone. The regenerated bone could be used for implant placement without exposure to the implant's rough surface. In addition, the alveolar bone and alveolar contour regenerated by the tooth transplantation showed no significant decrease even two years after the installation of the final prosthesis, and they maintained their esthetic condition. The results indicate that tooth transplantation with healthy periodontal tissue helps regenerate bone defects.