骨性Ⅲ类错牙合上颌拔牙与不拔牙去代偿对双颌手术矫治效果的影响

目的评价骨性Ⅲ类畸形双颌手术患者术前正畸上颌拔牙与不拔牙去代偿的效果及对术后的影响。方法选取36例在中国医科大学口腔医院进行正畸正颌外科联合治疗的骨性Ⅲ类错牙合畸形患者,其中18例术前正畸采取拔牙矫治,另18例未拔牙。对2组病例术前正畸后及治疗结束后的X线头颅定位侧位片进行对比研究。结果术前正畸后,拔牙组的U1-SN、鼻唇角（Cm-Sn-UL）和覆盖都较非拔牙组有明显变化,差异有统计学意义（P<0.05）。拔牙组下颌平均后退（8.66±1.42）mm,非拔牙组下颌平均后退（6.21±3.06）mm,二者间差异有统计学意义（P<0.05）;治疗结束后,拔牙组ANB、U1-SN、NA-PA在正常值范围内（P>0.05）。结论在骨性Ⅲ类畸形的正畸正颌外科联合治疗中,上颌拔牙术前正畸能够更彻底地去代偿,真实反映原有骨性畸形,使下颌能够后退至更加理想的位置,从而更好地矫治凹面型。

The effect of extraction and non-extraction decompensation to bimaxillary orthognathic surgery in skeletal class III malocclusion

Objective To evaluate the effect of extraction and non-extraction decompensation to bimaxillary orthog-nathic surgery in skeletal class Ⅲ malocclusion and the effect on postoperative.Methods Records of 36 completed surgical-orthodontic treatment skeletal class Ⅲ malocclusion patients were obtained from School of Stomatology,China Medical University,18 underwent maxillary premolar extraction,the other 18 underwent non-extraction.Their post-decompensation and postsurgery cephalometric radiographs were analyzed objectively,and their profile scissors-shadows in different groups were evaluated subjectively.Results The cephalometric index of post-presurgical orthodontics showed that there were significant deviations between the extraction and non-extraction groups including U1-SN,Over-jet and Cm-Sn-UL values(P<0.05).During surgery,mandible was retruded(8.66±1.42) mm in extraction group compared with(6.21±3.06) mm in non-extraction group(P<0.05).After surgery,the extraction group achieved more normal ANB, U1-SN,NA-PA values(P>0.05).Conclusion Maxillary premolar extraction can make incisor decompensation more complete so that mandible can be retruded to more ideal position and concave face can be successfully corrected.