摘要目的 分析拔除4颗第二双尖牙的Ⅲ类错(牙合)患者正畸治疗前后的软硬组织变化.方法 9例Ⅲ类错(牙合)患者,平均年龄14.8±2.7岁,拔除4颗第二双尖牙应用直丝弓矫治技术矫治,测量治疗前后头颅侧位片中软硬组织测量项目;用SPSS软件做配对T检验,分析治疗前后的差异.结果 矫治前后骨性测量项目ANB,MP-SN,PP-MP,Y轴未见明显改变(P＞0.05);牙性测量项目U1-NA减少4.0°,L1 NB减少8.2°,IMPA减少7.2°,U1-L1增加12.2°(P＜0.05);软组织测量项目LL-SnPg'减少2.0 mm(P＜0.05),UL-SnPg'减少0.5 mm(P＞0.05).结论 经拔除第二双尖牙矫治的Ⅲ类错(牙合)患者咬合关系得以调整,软组织侧貌改善,上下颌骨矢状向和垂直向位置关系未见改变.

abstractsObjective To analyse cephalometric changes after 4 second premolars extraction in Class Ⅲ malocclusion.Methods Pretreatment and posttreatment cephalograms of 9 Class Ⅲ malocclusion cases were selected for the study,average age 14.8 ± 2.7 years,who had four second premolars extracted and straight wire technic treated.Dentoskeletal and soft profile changes were measured and paired t test performed by SPSS.Results Skeletal measurements:ANB,MP SN,PP MP,Y Axis,had no significant changes during treatment.But U1-NA,L1-NB,IMPA decreased by 4.0°,8.2°,7.2° (P＜0.05),respectively,and U1-L1 increased 12.2° (P＜0.05).LL SnPg' decreased 2.0 mm (P ＜ 0.05).Conclusions Occlusion relationship and soft tissue profile were greatly improved in Class Ⅲ malocclusion after treated by four second premolar extraction,while there was no skeletal change in the cases.