Effects of sagittal split ramus osteotomy on temporomandibular disorders in seventy-two patients.

Preoperative and postoperative temporomandibular disorders (TMDs) were observed in 72 patients before surgical-orthodontic treatment and about 2 years after bilateral sagittal split osteotomy. Prevalence and degree of TMD were assessed using the modified clinical dysfunction index of Helkimo. A total of 49 women and 23 men (mean age 32 years) were included in the study. To find out which patients benefit most from the treatment, the sample was classified into subgroups--myogenous, arthrogenous, or both components of TMD. The prevalence of clicking and headache decreased significantly with the treatment, while the incidence of crepitation increased. In general, severity of the dysfunction was greatly reduced. Furthermore, multiple regression analysis showed that patients with excessive overjet and previous occlusal splint therapy benefit most from orthognathic treatment. In addition, patients with signs of mainly myogenous origin got more relief from their dysfunction than patients with mainly arthrogenous components of TMD. The results suggest that in patients with severe maxillomandibular discrepancy surgical-orthodontic therapy is a good choice of treatment for reducing myogenous TMD pain and discomfort.