Tomographic assessment of alterations of the temporomandibular joint after surgical correction of mandibular prognathism.

The aims of this study were to identify absolute condylar displacements and temporal fossa changes and to assess alterations in the condyle-fossa relationships after bilateral vertical ramus osteotomy for correction of mandibular prognathism. Twenty-four patients had linear tomograms taken of their temporomandibular joints within 1 week preoperatively and 6 months postoperatively. To ensure identical orientation of the focusing plane, a custom-made headholder was constructed and the head of the patient was positioned on the x-ray table in a standardized way. All radiographs were traced, and superimposition was made on stable structures, such as the mastoid cells of the temporal bone, the auditory meatus, the zygomatic arch, and the anterior cranial base. The results of the study indicated that, 6 months postsurgery, the only statistically significant change existed in the posterior joint space, which showed an average increase of 0.7 mm (P = .003). All other variables showed that the condylar position within the joint tended to approach its preoperative value. Small resorptive alterations in the glenoid fossa were also noticed.