Asymmetry assessment using cone beam CT. A Class I and Class II patient comparison

OBJECTIVE: To estimate possible differences in skeletal asymmetry between patients with skeletal Class I and skeletal Class II relationships. MATERIALS AND METHODS: Cone beam computed tomography (CBCT) images were examined from 70 consecutive patients who presented for orthodontic care and fit the inclusion criteria. Asymmetry was quantified using an asymmetry index developed by Katsumata et al. Anatomic landmarks were defined and reference planes were established to determine the asymmetry of the landmarks using a constructed coordinate plane system. Thirty randomly selected patients were reanalyzed to assess the reliability of the method. RESULTS: Statistical analysis did not find any significant relationship between asymmetry and A-P skeletal relationship for any of the landmarks. Asymmetry index scores were reproducible within a certain range of agreement for each landmark. CONCLUSIONS: Based on this study, the discrepant jaw growth resulting in a Class II skeletal pattern results in no more skeletal asymmetry than Class I skeletal patterns.