[Comparison of condylar position between Angle Class I and Class II malocclusion in teenagers].

Purpose: To analyze and compare the difference of condylar position between Angle Class I and Class II malocclusion patients using cone-beam CT (CBCT).

Methods: Thirty Class I patients, 30 Class II division 1 patients and 30 Class II division 2 patients were selected in this study. Each patient underwent CBCT. The images in the oblique position perpendicular to the condyloid process were reconstructed by Examvision software. The joint space was measured by Exam Vision software. The data were processed with SPSS17.0 software package.

Results: The upper joint space was larger in Class II, the posterior joint space was smaller in Class II patients; and in Class II division 1 patients, both of the upper and anterior joint spaces were larger than in Class II division 2 patients，the differences were significant (P<0.05). The length of condyle was longer in Class I patients than in Class II patients.

Conclusions: The condylar position in Class II division 2 patients was lower and further backward. The length of condyle is shortest in Class II division 2 patients.