中文摘要：

目的 对比联合应用前方牵引器关闭拔牙间隙与滑动法关闭拔牙间隙矫治恒牙早期安氏Ⅲ类错[牙合]的临床疗效。方法 选择恒牙早期安氏Ⅲ类错[牙合]患者30例，随机分为两组，每组15例。治疗组口内直丝弓矫治器联合应用前方牵引器关闭拔牙间隙进行矫治。对照组口内直丝弓矫治器滑动法关闭拔牙间隙进行矫治。在治疗前后分别拍摄X线头颅侧位定位片进行头影测量分析。结果 治疗开始后6—12个月，治疗组拔牙间隙关闭，安氏Ⅲ类错[牙合]纠正，上颌骨前方生长明显，下颌骨向前方生长抑制。SNA平均增加1．40°，SNB平均减少2．50°，ANB增大3．90°。对照组拔牙间隙关闭，上下颌骨无明显改变，SNA平均减少0．12°，SNB平均增加0．27°，ANB减少0．150°Ⅲ类骨面型仍存在。结论 在恒牙早期联合应用前方牵引器关闭拔牙间隙并矫治安氏Ⅲ类错[牙合]能促进上颌骨前移，抑制下颌骨向前方生长，可有效改善侧貌外形。

英文摘要：

Objective To compare the clinical effects of combined Straight-wire appliance with protraction facemask and sliding to treat early permanent dentition Class m malocclusion and close the extraction spaces of the second premolars. Methods 30 eases of Class m malocclusion were selected. The patients were divided into two groups. Combined Straight-wire appliance with protraction facemask was used to close the extraction spaces of the second premolars of the treated group. Sliding of Straight-wire appliance was used to close the extraction spaces of the second premolars of the control group. Lateral cephalometric films were taken at the beginning and in the end of the treatment for comparison. Results After 6 - 12 months, the extracted spaces of 15 cases of the treated group have been closed, while corrected Class malocclu sion may improve maxillary growth and inhibit mandibular growth. SNA increased by 1.40° averagely; SNB decreased by 2.50° averagely; ANB was increased by 3.90°. 15 cases extracted spaces have been closed in the control group, but maxillary growth and mandibular growth. SNA decreased by 0.12° averagely; SNB increased by 0.27° averagely; ANB was increased by 0.15°. Class m facial type didn＇t change.Conclusions It suggested that early treatraent by Straight-wire appliance with protraction facemask in Class m malocclusion may improve maxillary growth and inhibit mandibular growth, while it can close the extracted spaces.