Abstract
Recently, intraoral vertical ramus osteotomy (IVRO) has been applied to patients with jaw deformities as a method for orthognathic surgery in many institutes.
This procedure is relatively easy because the use of special instruments is not necessary and few cases show sensory disturbance in the mental region due to surgical damage of the inferior alveolar nerve. However, the postoperative stability of this method remains unclear. Therefore, to clarify the skeletal (point B) and dental (axis and extrusion) stability of this procedure, the postoperative follow-up data of 12 cases that were treated with IVRO bilaterally were retrospectively investigated.
Point B of the mandible on lateral cephalograms was measured in each case preoperatively, immediately after maxillomandibular fixation (MMF), at MMF removal, and 3 months, 6 months, and 1 year after the operation. In addition, the changes in the upper and lower medial incisors were simultaneously analyzed concerning their axes and extrusion by lateral cephalography and their postoperative occlusal findings were also evaluated.
The results were as follows:
1) The position of point B was remarkably changed posteriorly and inferiorly at MMF removal, and this position was maintained at all follow-up examinations.
2) There were three cases that showed open bite at MMF removal. These cases could obtain good occlusions through postoperative orthodontic treatment.
In conclusion, the results suggested the necessity of skeletal maxillomandibular fixation for good occlusal stability.
