序列拔牙与恒牙期拔牙矫治的稳定性比较

目的：比较序列拔牙及恒牙期拔牙矫治的稳定性。方法：20例序列拔牙矫治患者、20例恒牙期拔除4个第一双尖牙矫治患者,均采用直丝弓矫治技术治疗,平均戴用保持器2年。主动治疗结束时（T2）、保持结束后5年（T3）测量下颌模型6项指标、头颅定位侧位片9项指标,用配对t检验对数据进行统计分析。结果：与T2时相比,两组患者在T3时下颌尖牙间宽度、磨牙间宽度、牙弓长度均减小;拥挤度、覆、覆盖有所增大;上中切牙与SN夹角、IMPA、下中切牙与NB距离略有增加;上下切牙夹角减小。组间差异无统计学意义。结论：两组均表现一定程度的复发,序列拔牙与恒牙期拔牙矫治在观察阶段的稳定性无统计学差异。

Evaluation of Serial Extraction Versus Premolar Extraction in Permanent Dentition with Special Reference to Stability

Objective：To assess whether significant difference exists between the postretention stability experienced in serial extraction and late premolar extraction orthodontic treatments.Methods：The sample consisted of 20 patients who had undergone serial extraction of four first premolars.The patients were matched with subjects from the premolar extraction during permanent dentition to form pairs.All patients were treated with straight wire appliance plus two-year retention.Long-term measurements were made on the final records at posttreatment（T2）,and at minimum of 5-year postretention（T3）.The data was analyzed according to the paired t-test.Results：Arch length and arch width typically decreased after retention as crowding,overbite,overjet increased in both groups.During the follow-up period the anterior teeth moved forward for both groups.But all the differences were not statistically significant.Conclusion：Serial extraction patients might be not better aligned postretention than late extraction patients.No statistically significant differences were recorded between the two groups from T2 to T3.