Effects of orthognathic surgery on temporomandibular joint dysfunction. A controlled prospective 4-year follow-up study.

A prospective follow-up study was performed to examine the influence of contemporary orthognathic treatment on signs and symptoms of TMJ dysfunction. Sixty consecutive patients were examined once preoperatively and twice postoperatively, and Helkimo's Anamnestic and Dysfunction Indices (Ai and Di) were determined. The prevalence of headache was also assessed. The average follow-up was 4 years from the initial examination. A group of 20 patients with a similar type and grade of dentofacial deformity, who did not wish to have surgery or other occlusal therapy, served as a control group. The majority (73.3%) of the patients had signs and symptoms of TMJ dysfunction (TMD) in the initial phase. At final examination the prevalence of TMD had been reduced to 60% (P=0.013). There was a dramatic improvement in headache: initially 38 (63%) patients reported that they suffered from headache, but at the final visit only 15 (25%) did so. It is concluded that functional status can be significantly improved and pain levels reduced with orthognathic treatment. The risk for new TMD is extremely low. No association, however, could be shown between TMD and the specific type or magnitude of dentofacial deformity.