RESUMEN
A 22-year-old male was admitted to our hospital with suspected bone tumor of the right mandible. The patient's facial disharmony indicated class III malocclusion and mandibular prognathism. Biopsy was obtained from the bony lesion, and histological fingings revealed typical characteristics of ameloblastoma. During marsupialization, presurgical orthodontic treatment was given.<BR>A surgical procedure was planned by using his X-rays and presurgical model cast. The right mandible was resected without concominant removal of the neurovascular bundles. Subsequently, the left-side mandible was set back by sagittal split ramus osteotomy and the right-side mandible was simultaneously reconstructed by free illiac bone grafting.<BR>After surgery, the facial proportion and profile were improved. The missing teeth and associated structures were replaced by partial denture. The patient restored normal occlusal function and mastication.