关键词: 下颌偏斜, 骨性Ⅱ类, 髁突形态, 横向??平面

Abstract: Objective    To explore the condylar morphology and its association with frontal occlusal plane characteristics in adult skeletal Class Ⅱ patients with mandibular deviation using cone beam CT（CBCT），aiming to provide references for clinical diagnosis and treatment. Methods    Sixty patients（40 in the deviation group：menton deviation > 2 mm；20 in the symmetric group：menton deviation ≤ 2 mm）were enrolled，who were treated in the Department of Stomatology，General Hospital of Northern Theater Command，PLA，from January 2022 to August 2024. Pre-treatment CBCT data were obtained and input into Mimics Research 21.0 software for 3D reconstruction，the condyle was separated and reconstructed，and the condylar volume and surface area were measured. Vertical distances from bilateral maxillary canine/molar cusps to the Frankfort horizontal plane were recorded，with absolute differences defined as OC3（maxillary canine）and OC6（maxillary molar）deviation. The side with the smaller distance was the deviated occlusal plane. The relationship between frontal occlusal plane deviation and  menton deviation was analyzed. Results    There were no statistically significant differences in condylar volume or condylar surface area between the bilateral sides in the symmetric group（P > 0.05）. The mean values of the left and right sides were calculated and then compared with those of the deviation group. In the deviation group，the condylar volume［（1 460.44 ± 425.70）mm3］and condylar surface area［（763.32 ± 158.28）mm2］on the deviated side were smaller than those on the non-deviated side［（1 641.95 ± 395.70）mm3，（839.47 ± 143.83）mm2］（t = 6.106，6.686；P < 0.05），with statistically significant differences. The condylar volume and surface area of the deviated side in the deviation group were lower than those in the symmetric group［（1 682.88 ± 305.96）mm3，（852.61 ± 116.39）mm2］（t = 2.080，2.235；P < 0.05），and the differences were statistically significant. No significant differences were found in condylar volume or condylar surface area between the non-deviated side of the deviation group and the symmetric group（P > 0.05）. OC3 and OC6 in the deviation group［（1.45 ± 0.50）mm，（1.48 ± 0.68）mm］were higher than those of the symmetric group［（0.41 ± 0.23）mm，（0.69 ± 0.39）mm］（t = 8.819，4.803；P < 0.001）. Both OC3 and OC6 were positively correlated with menton deviation（r = 0.773，0.704；P < 0.001），and the occlusal plane deviation direction was associated with the menton deviation direction（P < 0.001）. Conclusion     Compared with adult patients with skeletal Class Ⅱ and mandibular symmetry，adult patients with skeletal Class Ⅱ mandibular asymmetry present smaller condyles on the deviated side and a larger frontal occlusal plane canting. Moreover，frontal occlusal plane canting may be correlated with menton deviation.

Key words: mandibular deviation, skeletal Class Ⅱ, condylar morphology, frontal occlusal plane