支抗控制在双颌前突畸形矫治中的作用

目的 研究支抗控制在滑动直丝弓技术矫治双颌前突畸形中的作用。方法 利用国产直丝弓托槽，滑动技术矫治双颌前突畸形患者30例，使用口外唇弓和不使用口外唇弓者各15例，均拔除4颗第一双尖牙，均采用一步法关闭拔牙间隙。将矫治前后的头颅侧位定位片进行对比分析，其变化量进行独立t检验。结果 矫治后戴口外唇弓组争不戴口外唇弓组上颌磨牙分别前移3．21mm和4．67mm；下颌磨牙分别前移3．32mm和5．21mm；两组的差异有统计学意义（P〈0．01）。前牙内收量戴口外弓组上颌为5．19mm，下颌为4．43mm；不戴口外弓组上颌为3．43mm。下颌为2．62mm。两组的差异有统计学意义（P〈0．01～0．001）。结论 口外唇弓在使用国产直丝弓托槽，运用滑动机制矫治双颌前突畸形中较有效地保护了后牙支抗，从而减少面部突度。

Importance of anchorage control in bimaxillary protrusion correction by straight wire appliance

Objective To investigate the effects of anchorage control in bimaxillary protrusion correction by straight wire appliance.Methods Thirty patients with bimaxillary protrusion treated with straight wire appliance were divided into two groups with and without headgear during treatment according to some criteria. Four premolars in all patients were extracted and extraction spaces were closed with one-step sliding methods. The cephalometric changes of the two groups were examined before and after the treatment.Results The amount of mesial movement of upper and lower first molars was smaller in the group with headgear (3.21mm and 3.32mm) than that in the group without headgear (4.67mm and 5.21mm) (P<0.01). The amount of lingual movement of the tip of upper and lower incisor was larger in the group with headgear (5.19mm and 4.43mm) than that in the group without headgear (3.43mm and 2.62mm) (P<0.01).Conclusion Anchorage control with headgear might help decrease soft tissue convexity in the treatment of bimaxillary protrusions with straight wire appliance.