??????????????????γ????????????Ч???

目的    探讨拔除第一磨牙矫治成人双颌前突错牙合的可行性。方法    选择2003年1月至2008年6月大连市口腔医院正畸科收治的成人双颌前突患者20例，按照磨牙是否存在病变或缺失分为试验组和对照组，每组10例。试验组：患者均存在1颗或多颗第一磨牙严重病损或者早失；矫治设计拔除病损侧的第一磨牙而保留健康的双尖牙，早失磨牙侧不再减数，健康侧常规拔除第一前磨牙。对照组：矫治设计常规减数4颗第一双尖牙。所有病例均使用直丝弓矫治器，采用传统支抗技术，通过头影测量分析各组疗效。结果    试验组和对照组治疗后头影测量显示，面凸角减小、上下唇角增加，反映侧貌突度减小。矫治后硬组织改变主要为上下前牙内收。试验组患者平均疗程（34.5±4.5）个月，磨牙拔牙间隙完全关闭；治疗后第三磨牙与对牙合的第二或第三磨牙均建立良好咬合关系，且第二磨牙与第三磨牙牙根平行状况良好。对照组患者平均疗程（22.5±3.5）个月，上前牙回收幅度较试验组明显。结论    对于第一恒磨牙存在严重龋坏或过早缺失的成人双颌前突患者，经过仔细的支抗设计和精心的临床操作，非常规拔除第一磨牙与常规减数第一双尖牙矫治均可获得较满意的临床治疗效果，但常规减数治疗上前牙回收幅度更大且疗程较短。

A comparison between the unnatural extraction and routine extraction in the treatment of bimaxillary protrusion adult cases

Objective To assess the treatment outcome between the extraction of the unhealthy first molars and first premolars in the treatment of bimaxillary protrusion adult cases.Methods Twenty bimaxillary protrusion adult cases were selected in Dept.of Orthondontics,Da Lian Dental Hospital from Jan.2003 to June 2008,mean age 25.5 years old.Group A：treated with the extraction of unhealthy first molars.Group B：treated with the extraction of four first premolars.The treatment effects were evaluated by pre-and post-cephalometric films.Results The mean values of Ns-Sn-Pos decreased,while the angles of upper and lower lip increased.In Group A,the average treatment duration was 34.5±4.5 months.The extraction spaces of first molars were closed in all cases,good occlusal relationships were achieved,and soft tissue profile modified.The third molars moved into occlusal contact,and the roots of second molars and third molars were paralled.The average treatment duration was 22.5±3.5 months in Group B,and upper incisors moved more backwards than that of group A.Conclusion For those bimaxillary protrusion adult cases,the extraction of the unhealthy first molars would obtain satisfactory results by careful anchorage design and proper clinical operation.But compar with the traditional extraction pattern,the latter ensures more upper incisors retraction,and less time-consuming.