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目的探讨直丝弓矫治技术滑动法与关闭曲法关闭拔牙间隙对支抗磨牙位置及疗程的影响。方法选择2006年1月至2009年3月在中国医科大学口腔医学院正畸科拔除4颗第一前磨牙或2颗上颌第一前磨牙的安氏Ⅱ1或安氏Ⅰ类双颌前突患者33例,使用0.46mm(0.018英寸)直丝弓矫治装置充分排齐整平上下牙列后采用两步法关闭拔牙间隙,将上颌第二磨牙纳入矫治序列,且均未采用特殊加强支抗方法。拉尖牙向远中完成后,随机分为滑动法组(17例)和关闭曲法组(16例),分别使用滑动法或关闭曲法关闭剩余间隙,对关闭间隙前后的X线头颅侧位片进行测量分析。结果滑动法组和关闭曲法组的上颌第一磨牙分别近中移动(3.4±1.4)mm和(3.0±1.8)mm,两组差异无统计学意义(P>0.05)。内收4颗前牙,滑动法组疗程为(6.0±2.4)个月,关闭曲法组疗程为(6.4±2.2)个月,两组差异无统计学意义(P>0.05)。结论使用0.46mm(0.018英寸)直丝弓矫治装置排齐整平上下牙列,并在矫治初期即将上颌第二磨牙纳入矫治序列的拔牙病例,正畸医生可根据个人习惯使用滑动法或关闭曲法回收前牙。

Comparison of two methods of closing the extraction space using straight wire appliance

Objective To compare the differences between closing loop and sliding technique in anchorage demand and treatment time. Methods Totally 33 cases of Class Ⅱ division 1 or Class Ⅰbimaxillary protrusion malocclusion,who were treated by 4-premolar-extraction or 2-premolar-extraction,were selected and divided into two groups randomly. In all cases,the second maxillary molars were bonded at the beginning of treatment and no special method was used to improve the anchorage. The 0.46 mm straight wire appliance and two-step method were used. After the alignment and leveling as well as the retraction of canine,closing loops were used in one group（16 cases）and sliding technique was used in the other group（17 cases）for incisor retraction. Cephalometric films before and after treatment were taken and analysed. Results The first maxillary molar moved mesially for（3.4 ± 1.4）mm and（3.0 ± 1.8）mm in sliding technique group and closing loop group respectively. There were no significant differences between the two groups（P 0.05）. The time of incisor retraction was（6.0 ± 2.4）months and（6.4 ± 2.2）months in sliding technique group and closing loop group respectively. The difference was not significant（P 0.05）. Conclusion Orthodontic doctors could use closing loop or sliding technique according to personal habits in space closure with two-step method,using 0.46 mm straight wire appliance while the second maxillary molar is bonded at the beginning of the treatment.