Function of the masticatory system in 20 patients with mandibular hypo- or hyperplasia after correction by a sagittal split osteotomy.

Twenty patients with malocclusions were examined for signs and symptoms of craniomandibular disorders (CMD) before surgical correction of their anomalies. Such signs and symptoms were very common and were in many patients the main reason for requesting treatment. Eight patients had rigid and 12 non-rigid fixation. All patients were re-examined 1 year after surgery. This examination showed a statistically significant improvement of signs and symptoms of CMD but those who had had non-rigid fixation showed a statistically significant impairment in maximal mouth opening while no such change was noted in those treated with rigid fixation. Eight patients reported significant reduction of their recurrent headaches. It is concluded that surgical correction of malocclusion has a beneficial effect not only on the aesthetic appearance and dental occlusion but also on signs and symptoms of CMD.