关键词: 骨性Ⅱ类错牙合, 上颌磨牙近远中倾斜角度, 锥形束CT, 垂直骨面型

Abstract: Objective: To measures the mesiodistal angulation of maxillary molars of skeletal class II female by CBCT, to provide reference for the clinical treatment. Methods: Thirty patients with skeletal class II malocclusion and 10 cases for normal occlusion were selected. CBCT was taken before treatment and induced into Invivo Dental 5 software. The occlusal plane, frankfort horizontal plane, and the palatal plane were set as the reference plane, the inclinations of the maxillary molars were measured. Individual normal occlusion and skeletal class II malocclusion were examined. One-way ANOVA were used to analyze the differences between high angle group, average angle group, and low angle group of skeletal class II. Pearson correlation analysis was used for different vertical facial types between the measurement items and mandibular plane angle and plane angle. Results: There existed distal inclining trend of the first maxillary molar for the skeletal class II patients. From low-angle group to high-angle group, there existed distally declining trend at the first maxillary molar. When the occlusion plane was for reference, the second maxillary molar has distally inclining trend from high-angle to low-angle. Conclusion: In order to compensate the disharmony between mandible and maxillary, there existed distal trend of maxillary first molar for skeletal class II malocclusion. The first maxillary molar for skeletal class II malocclusion compensated the distal inclination with the increasing of mandible plane angle. However, the distally inclining trend of second molar was not obvious. No matter which kind of skeletal class II vertical facial pattern, the first maxillary molar compensated the inclining movement to maintain the occlusal force to transfer along the long axis of tooth.

Key words: Skeletal class II, Mesiodistal angulation of maxillary molar, Cone beam computed tomography, Vertical skeletal type