骨性Ⅲ类错[牙合]上颌牙弓与基骨的三维代偿研究

Three-dimensional Compensation Study of Maxillary Dental Arch and Basal Bone in Skeletal Class Ⅲ Malocclusion

目的:研究骨性Ⅲ类错[牙合]上颌牙弓相对于基骨的三维代偿,为临床诊疗提供理论支持。方法:选取骨性Ⅲ类错[牙合]和个别正常[牙合]样本各50例,拍摄CBCT影像资料并建立三维坐标系,对二者的上颌牙弓点相对于基骨点的差值坐标进行统计分析。结果:骨性Ⅲ类错[牙合]X轴坐标值在第一前磨牙至第二磨牙区大于个别正常[牙合]组;Y轴坐标值除尖牙与第二磨牙外,绝对值均大于个别正常[牙合]组,方向均为负向;Z轴坐标值在第一前磨牙至第一磨牙处绝对值小于个别正常[牙合]组,第二磨牙处绝对值大于个别正常[牙合]组。结论:骨性Ⅲ类错[牙合]上颌切牙唇向倾斜,后牙颊向和近中向倾斜,后牙区除第二磨牙外垂直距离代偿性降低。

Objective:Study the three-dimensional compensation of maxillary teeth and basal bone of skeletal Class Ⅲ malocclusion to provide theoretical basis for clinical diagnosis and treatment.Methods:50 patients with skeletal Class Ⅲ malocclusion and 50 normal patients were selected to take CBCT images.The image data was converted and a three-dimensional coordinate system of the maxillary region was established.The differences between dental arch points and basal points of upper jaw were analyzed.Results:Compared to normal occlusion,the X coordinate value of the skeletal Class Ⅲ malocclusion was larger in the first premolar to the second molar area.Except for the maxillary canine and second molar,Y coordinates of the other teeth were larger than that of individual normal occlusion,and the direction was negative.The absolute value of the Z coordinates of the first premolar to first molar were smaller than that of normal occlusion,and the height in the vertical direction was decreased,but the absolute value of second molar was larger than the normal occlusion,and the height in the vertical direction was increased.Conclusion:The maxillary incisors of skeletal Class Ⅲ malocclusion incline to labial side.The posterior teeth incline to buccal and mesial,and the height is lowered.So the compensation of maxillary dental arch and basal bone should be considered in orthodontic treatment plan.