减数拔牙对正畸治疗患者下颌第三磨牙近中倾斜角度和萌出间隙及下颌前部拥挤复发的影响

The Effect of Orthodontic Treatment with Extraction on the Mesial Canting Angle of Mandibular Third Molars,Eruption Gap and the Recurrence of Crowding in the Anterior Part of the Mandible in This Patient

目的:研究牙颌畸形患者正畸治疗中减数拔牙对下颌第三磨牙近中倾斜角度(M3-⊥FH)、萌出间隙(ES)及下颌前部拥挤复发的影响。方法:选取2018年1月-2019年6月于笔者医院就诊的106例牙颌畸形患者为研究对象,均采用直丝弓矫治技术正畸治疗,其中53例实施拔除矫治术(A组,减数第一前磨牙),53例未进行拔牙矫治(B组)。比较两组患者矫治前后CBCT图,并测量M3-⊥FH、ES值及下颌平面角(MP-SN)、ANB角的变化情况及前牙拥挤度。随访3年,比较两组下颌前部拥挤复发率,并Logistic回归分析下颌第三磨牙对M3-⊥FH、ES及下颌前部拥挤复发的影响因素。结果:正畸治疗后,两组M3-⊥FH值较正畸治疗前显著下降,ES值较正畸治疗前显著增大,差异有统计学意义(P<0.05),两组M3-⊥FH、ES值组间比较有差异有统计学意义(P<0.05);A、B两组前牙拥挤度及下颌前部拥挤复发率(71.70%vs 79.25%)比较无统计学意义(P>0.05);A组治疗后,MP-SN、ANB角明显小于对治疗前,差异有统计学意义(P<0.05);治疗后,MP-SN、ANB、M3-⊥FH、ES及是否拔牙与正畸治疗后M3-⊥FH呈负相关(P<0.05),ANB和是否拔牙与正畸治疗后ES呈正相关(P<0.05)。结论:正畸治疗中,下颌第三磨牙对M3-⊥FH、ES有一定影响,拔牙会减小矫治后对M3-⊥FH、ES的影响程度,但与下颌前部拥挤复发无直接关系。

Objective To study the effect of tooth extraction during orthodontic treatment of patients with taurodontism on the mesial inclination angle(M3-⊥FH),eruption gap(ES),and the recurrence of crowding in the anterior part of the mandible.Methods A total of 106 patients with occlusal deformities who visited our hospital from January 2018 to June 2019 were treated orthodontically using the straight wire arch orthosis technique,of which 53 cases were implemented with extraction orthopedics(group A,reduction of four first premolars)and the remaining 53 cases did not undergo extraction(group B).CBCT maps of the two patients before and after correction were compared and the values of M3-⊥FH,ES,and the changes in the plane angle of the mandible(MP-SN),anb angle,and crowdedness of the anterior teeth were measured.Patients were followed up for 3 years,and the anterior mandibular crowding relapse rate was compared.Logistic regression was used to analyze the influencing factors of mandibular third molars on M3-⊥FH,ES and lower anterior teeth crowding relapse.Results After orthodontic treatment,there was decrease in M3-⊥FH value,and an increase in ES value in both groups(P<0.05),and post-treatment values showed significant difference between groups(P<0.05).A,B there was no significant difference in the percentage of crowding on the anterior teeth and the recurrence of crowding on the anterior part of the mandible between the two groups(71.70%vs 79.25%,P>0.05).MP-SN and ANB angles were decreased after treatment(P<0.05).MP-SN,ANB,M3-⊥FH,ES and extraction conditions were negatively correlated with M3-⊥FH after orthodontic treatment(P<0.05),ANB and whether extraction were positively correlated with es after orthodontic treatment(P<0.05).Conclusion In orthodontic treatment,the mandibular third molar has a certain influence on M3-⊥FH and ES,while extraction can reduce influence degree on M3-⊥FH and ES after orthodontic treatment,and it has no direct relationship with the relapse of anterior mandibular crowding.