Changes in mandibular position during treatment with disk-repositioning onlays: a roentgen stereophotogrammetric study.

Seven patients with temporomandibular joint disk displacement were treated with disk-repositioning onlays, and changes in the mandibular position were studied by means of roentgen stereophotogrammetry. A wide range of changes in mandibular position was seen at cementation of the onlays and during the observation period. On an average, recapturing of the disk and cementation of the onlays lowered the mandible by 2.5 mm and protruded it by 0.5 mm. During the observation period of 7 months the mandible had a tendency to resume its original position. The relapse was 80% in the sagittal plane, 70% in the transverse plane, and 12% in the vertical plane. It was concluded that disk-repositioning onlays can be used to lower the mandible with a relatively small relapse. Changes in the horizontal plane, however, seem to be less stable.