中文摘要：

目的对比不同部位种植支抗治疗露龈笑合并凸面型拔牙患者的正畸效果及疗程,探讨不同方法的临床适用性。方法选取航天中心医院口腔正畸科2007年2月-2012年9月因上颌前部牙槽骨垂直向发育过度造成的露龈笑合并凸面型需拔除四颗双尖牙的患者86例,随机分为两组,每组43例。A组利用前牙区一颗种植钉结合后牙区两颗种植钉同时压低及内收上前牙,并同时弯制弓丝以维持良好的笑弧;B组先利用前牙区两颗种植钉压低上前牙,而后取出前牙区种植钉,利用后牙区两颗种植钉内收上前牙,比较治疗前后头影测量学指标并对比两组疗程、满意度。结果 A组平均（17.4±4.3）岁,男22名,女21名患者;B组平均（16.1±3.8）岁,男21名,女22名患者;两组性别、年龄差异无统计学意义;A组平均矫治时间（30.3±10.3）个月,B组平均矫治时间（35.2±11.2）个月,差异有统计学意义（P=0.036）;两组前牙压低及内收量差异无统计学意义。两组患者及医生对笑弧、笑线、侧貌的满意程度亦无统计学差异。结论前牙区不同部位种植体支抗联合后牙区种植支抗均可有效压低并内收上前牙,且均达到了令人满意的笑容和侧貌;但A组较B组可有效缩短疗程。

英文摘要：

Objective To compare orthodontic treatment course and effects of different sites of mini-implant anchorage on improving gummy smile of patients with convex profile who need teeth extraction, and explore the clinical applicability of these two methods. Methods From February 2007 to September 2012, 86 patients with convex profile and gummy smile due to vertical maxillary excess who were supposed to undergo teeth extraction in Aerospace Center Hospital were enrolled in this study, and they were randomly allocated into 2 groups with 43 cases in each group. Patients in group A were inserted with one miniscrew into anterior alveolar process and two miniscrews in posterior alveolar process. The maxillary anterior teeth were simultaneously retracted and intruded by means of miniscrew anchorage. At the same time, dentist bent arch wire was used to maintain well smile arcs of patients. Patients in group B were inserted with two mini-implants into anterior alveolar process to intrude maxillary anterior teeth. Then, the miniimplants were taken out, and two miniscrews were inserted into posterior alveolar process to retract anterior teeth. The pre-and posttreatment cephalometric measurements were analyzed. Then the courses of treatment and its satisfaction were compared between two groups. Results There was no statistical difference in gender, age, parameters of intrusion and retraction of anterior teeth and satisfaction between two groups. The treatment duration of group A was（30.3±10.3） months, which was significantly less than that in group B [（35.2±11.2） months（P=0.036）]. Conclusion Both two different sites of mini-implant anchorages inserting into anterior alveolar process combining with posterior alveolar process can intrude and retract maxillary anterior teeth effectively. Patients in both groups achieve satisfactory smile arc, smile line and facial profile. Moreover, one mini-implant being implanted between maxillary roots of central incisors and two miniscrews being inserted into posterior alveolar proc