先天缺失2颗下切牙患者侧貌特征和拔牙矫治前后侧貌变化

Facial profile of patients with congenitally missing 2 mandibular incisors and changes of facial profile before and after orthodontic treatment by extraction of 2 maxillary premolars

目的:分析先天缺失2颗下切牙患者的侧貌特征,探讨该类患者拔牙矫治前后的侧貌变化。方法:收集64例先天缺失2颗下切牙患者的头颅侧位片。64例患者的初诊侧位片用于分析患者的侧貌特征,其中38例患者拔除上颌2颗前磨牙进行矫治,初诊和治疗结束侧位片用于比较矫治前后的侧貌变化。对侧位片进行头影测量(包括硬组织和软组织项目),并对结果进行统计学分析。结果:与正常值比较,先天缺失2颗下切牙患者覆盖、覆牙合、ANB、U1-NA角、面角、Y轴角、Pg-NB、面突角、软组织面角、H角和颏唇沟至H线距较大,SNB、L1-NB角、L1-NB距、L1-MP、牙合平面角和颏唇沟角较小,差异均有统计学意义(P<0.05);拔牙矫治后,覆盖、覆牙合、U1-NA角、U1-NA距、U1-SN、H角和鼻唇沟至H线距变小,L1-NB角、L1-NB距、L1-MP、牙合平面角、Pg-NB和颏唇沟角变大,差异均有统计学意义(P<0.05)。结论:先天缺失2颗下切牙患者下颌发育不足但颏部发育充足,覆牙合覆盖较大,下颌切牙舌向倾斜,颏唇沟较深较锐。拔除上颌2颗前磨牙矫治后患者侧貌整体面型基本未变,但前牙咬合关系明显改善。

Objective:To analyze the facial profile of the patients with congenitally missing 2 mandibular incisors,and to investigate the changes of facial profile of the patients before and after orthodontic treatment by extraction of 2 maxillary premolars.Methods:The cephalometrics of 64 patients with congenitally missing 2 mandibular incisors were collected.The initial cephalometrics of 64 patients were used to characterize the facial profile.A total of 38 cases among all the 64 patients underwent the orthodontic treatment by extraction of 2 maxillary premolars,and the initial and final cephalometrics were used to compare the changes of facial profile before and after treatment.The cephalometric measurement(including hard tissue and soft tissue items)was performed and the results were analyzed statistically.Results:Compared with the normal values,the overjet,overbite,ANB,U1-NA angle,face angle,Y axis,Pg-NB,face convexity,soft tissue facial angle,H angle,and mentolabial sulcus to H-Line in the patients with congenitally missing 2 mandibular incisors were increased;SNB,L1-NB angle,L1-NB distance,L1-MP,occlusal plane angle,mentolabial sulcus angle were decreased,and the differences were statistically significant(P <0.05).After orthodontic extraction treatment,the overjet,overbite,U1-NA angle,U1-NA distance,U1-SN,H angle,and subnasale to H-Line of the patients were decreased;the L1-NB angle,L1-NB distance,L1-MP,occlusal plane angle,Pg-NB,and mentolabial sulcus angle were increased;the differences were statistically significant(P<0.05).Conclusion:The mandibular development is insufficient but the chin development is adequate in the patients with congenitally missing 2 mandibular incisors,with larger overjet and overbite,lingually inclined mandibular incisors,deeper and sharper mentolabial sulcus.After treatment by extraction of2 maxillary premolars,the overall appearance of the lateral profile of the patients remains unchanged,but the occlusion of anterior teeth is significantly improved.