Computed tomography morphology of the mandibular ramus at the lingual plane in patients with mandibular hyperplasia.

This study investigated the specific morphology of the mandibular ramus at the lingual plane in patients with mandibular hyperplasia using spiral computed tomography. The subjects were 25 patients with mandibular hyperplasia undergoing sagittal split ramus osteotomy and there were 20 patients without dentofacial deformities in the control group. The thickness of the mandible, diameter of the inner mandibular canal, width of the buccal bone marrow space, and the width of the buccal cortex and lingual cortex were measured at the lingual plane, which contained the lowest point of the mandibular foramen. The average thickness of the mandible was 8.5 mm in prognathic patients and 9.6mm in control patients. The average width of the buccal bone marrow space in mandibular hyperplasia patients was 1.5 mm and 2.5 mm in control patients. The mandibular ramus in patients with mandibular hyperplasia was thinner and the width of the buccal bone marrow space was smaller than in the control patients. The width of the buccal bone marrow space and the thickness of the mandible were significantly positively correlated.