Clinical and magnetic resonance findings in the temporomandibular joints of patients before and after orthognathic surgery.

It is difficult to achieve the correct position of the condyle in the temporal fossa during orthognathic surgery in angle class II patients with disorders of the temporomandibular joint. This led us to examine the TMJ of 25 of our own patients before and shortly after orthognathic operations. We recorded the clinical and magnetic resonance imaging findings of the temporomandibular joint preoperatively and three months postoperatively. The patients had skeletal class II dysgnathia and had been treated with fixed orthodontic appliances for a mean of two years and three months before operation. Operation resulted in a mean reduction of maximal incisor distance of 12 mm. In five of the 25 patients, the pattern of mouth-opening changed. Nine patients had less pain than before surgery, and nine had fewer abnormal joint sounds. The magnetic resonance imaging showed displacement of the articular disc in 38 of the 50 joints preoperatively and in 28 postoperatively. Degenerative joint changes were not improved by operation. Improvement of the disc position was achieved by repositioning of the condylar-disc complex during orthognathic surgery in angle class II patients. Clinical and magnetic resonance imaging findings regarding the temporomandibular joint in class II patients correlated significantly both preoperatively and postoperatively.