A case report of a large odontogenic cyst treated by dental implantation with mandibular reconstruction using an iliac bone graft

Odontogenic cysts are comparatively common, but large odontogenic cysts that extend into the unilateral mandible are rare. Here, we present the case of a patient with a large odontogenic cyst extending to the unilateral mandible by enucleation and mandibular reconstruction with an iliac bone graft, followed by occlusal reconstruction by dental implant treatment. The patient was a 69-year-old man who presented to a local dental clinic with swelling and increasing pain in the right mandible. Radiolucency in the right lower molar region and impacted wisdom teeth were identified, and he was referred to our department. A panoramic X-ray showed a well-defined radiolucency extending from the right angle of the mandible to the molar region, including the impacted wisdom tooth, and root resorption of the molars. Following antibiotic treatment to reduce inflammation, tooth extraction, biopsy, and fenestration were performed under general anesthesia. The histopathological diagnosis was radicular cyst. Fenestration treatment was continued, enucleation of the cyst and wisdom tooth extraction were conducted, with immediate mandibular reconstruction by iliac bone grafting. The right lower wisdom tooth was extracted, the cyst was enucleated, and an iliac bone block was grafted into the large defect in the right lower molar region of the mandible and fixed in place with a metal plate. The removed tissue was cystic. Computed tomography 18 months postoperatively showed mandibular bone formation, and the metal plate was removed under general anesthesia. Three years postoperatively, since the mandible had healed well, implants were inserted, and good occlusion was achieved.