Clinical analysis of condylar displacement evaluated by 3-D CT under the surgical correction of mandibular prognathism

Nam, Jeong Hun; Son, Jung Hee; Jung, Chang Wook; Jang, Hyun Jung; Lee, Sang Han

Abstract

This study was intended to contemplate the correlation between the amount of mandibular setback and the condylar positional change and to consider the interrelation between the temporomandibular joint dysfunction and the condylar displacement by using 3-D CT after orthognathic surgery in 40 patients(male 18, female 22). We took 3-D CT in centric occlusion 3 weeks before and 6 weeks after operation and measured the intercondylar distance, the distance and angle of condylar horizontal long axis and the amount of set back. The results were as follows : In positional change of condyle, distance values of MM', RLD and LLD and angle values of RCA and LCA were increased and distance values of RMD and LMD were decreased. then, It was found the tendency of medially rotated displacement of the condyle. but there was no statistical significance(p>0.05). In amount of mandibular set back, we found the condylar hange(T2-T1) which had increased tendency from Group 1 to Group 3 and decreased tendency of MM' from Group 1 to 3. but there was no statistical significance (p>0.05). There was some correlation between condylar change and TMJ dysfuction. It seemed that postoperative condylar change had influenced the postoperative TMJ dysfunction, though was no statistical significance (p>0.05). As we have observed the change of condylar axis in the group that complained of TMJ dysfunction after operation in cases of large amount of mandibular set back, do we consider that the more trying to onserve the condylar position will decrease the occurrence rates of the postoperative condylar displacement, TMJ dysfunction and the relapse.