3-DIMENSIONAL COMPUTED-TOMOGRAPHY EVALUATION OF POSTSURGICAL CONDYLARDISPLACEMENT AFTER MANDIBULAR OSTEOTOMY

Objective. The purpose of this study was to examine both condylar disp lacement of the temporomandibular joint after sagittal split ramus ost eotomy with rigid osteosynthesis and intraoral vertical ramus osteotom y without osteosynthesis in patients with mandibular prognathism by me ans of three-dimensional computed tomography. Study design. In this pi lot study, five patients treated with sagittal split ramus osteotomy a nd 5 patients treated with intraoral vertical ramus osteotomy were eva luated. A technique to superimpose a postoperative three-dimensional c omputed tomography image on its corresponding preoperative image was d esigned. Postoperative condylar displacement, rotation, and tilting we re measured in three-dimensional computed tomography images. Results. Within 3 to 6 months after surgery, changes in the inclination of the condylar axes were distinctly seen, although changes in the position o f the condyles within the joints were minimal. In particular, outward rotation of the condylar long axes after intraoral vertical ramus oste otomy was a frequent finding. Conclusions. The three-dimensional compu ted tomography superimposition technique was a practical method of eva luating postsurgical condylar displacement after mandibular osteotomy.