不同正畸方法对成人患者下颌第三磨牙的影响

Effects of different orthodontic treatment methods on mandibular third molar eruption

目的:比较不同的正畸治疗方法对成人患者下颌第三磨牙萌出状况的影响。方法:选取正畸治疗结束的成人患者80例,共有下颌第三磨牙154颗。按照下颌单侧拔牙的情况分为非拔牙组40颗,拔第一前磨牙组66颗,拔第二前磨牙组48颗。对术前、术后的曲面断层片测量下颌第三磨牙角度及萌出间隙,并且根据术后X线片选取116颗下颌第三磨牙判断其萌出水平。结果:正畸前后下颌第三磨牙角度的改变量在各组之间没有统计学差异(P>0.05)。而下颌第三磨牙间隙的变化量在3组之间均有高度的统计学差异(P<0.01),拔第二前磨牙组大于拔第一前磨牙组,拔第一前磨牙组大于非拔牙组。拔第二前磨牙组正畸后下颌第三磨牙的萌出水平显著优于非拔牙组和拔第一前磨牙组(P<0.05)。结论:成人正畸患者治疗前后下颌第三磨牙角度的变化与治疗方法关系不大,但其萌出间隙的变化有显著的差异,支抗越弱,间隙增加越多,萌出状况改善越明显。

Objective：To compare the effects of different orthodontic treatment methods on the eruption of mandibular third molar（M3）.Methods：80 posttreatment adult patients were selected for the study.154 mandibular M3 were divided into three groups according to the extraction conditions of unilateral mandibular teeth.40 were treated without extraction（non-extraction group）,66 were treated with the extraction of first premolar（4-extraction group）,and 48 were treated with the extraction of second premolar（5-extraction group）.The pretreatment and posttreatment panoramic radiographs were analysed.The angulation and the eruption space of mandibular M3 were measured.The eruption levels of 116 third molars were evaluated according to the posttreatment panoramic radiographs.Results：There were no significant differences in the change in mandibular M3 angulation from pretreatment to posttreatment groups（P〉0.05）.But there were significant differences in the change in mandibular M3 space among three groups（P〈0.01）.Space change in 5-extraction group was larger than that in 4-extraction group,and 4-extraction group was larger than non-extraction group.The eruption level of the M3 after orthodontic treatment was significantly higher in 5-extraction group than in non-extraction group and 4-extraction group（P〈0.05）.Conclusion：For adult orthodontic patients,mandibular M3 angulation changes regardless of the method of orthodontic treatment.But the space changes are significantly different,the weaker of the anchorage,the more spaces increased,the more improvement in eruption.