An analysis of changes in the dentofacial skeleton following orthodontic treatment in anterior open bite patients

目的 评价正畸治疗对开(牙合)患者牙、(牙合)、牙槽、颅面形态结构的影响,以及这些结构变化对前牙覆(牙合)关系建立的影响程度.方法 共纳入50例前牙开(牙合)患者,其中37例拔除双尖牙,13例拔除或先天缺失第三磨牙.对治疗前后的头颅侧位片进行头影测量分析(28个测量项目).治疗前后测量项目变化应用配对t检验,不同组间项目对比使用独立样本t检验.以治疗后覆(牙合)变化为因变量,应用多元线性回归筛选影响覆(牙合)建立的敏感因素.结果 50例开(牙合)患者治疗后上、下前牙明显内收与直立[U1-NA:(-2.43±3.86)mm,P＜0.001;U1/NA..-8.82°±9.53°,P＜0.001;L1/NB:-6.12°±6.82°,P＜0.001;U1/L1..14.40°±12.17°,P＜0.001],伴随下颌牙槽骨高度的伸长[(1.89±2.43) mm,P＜0.01],拔除及不拔除双尖牙组间测量项目变化无明显差异.线性回归方程显示,正畸治疗后上切牙角度及下牙槽骨高度变化是影响覆(牙合)变化的重要因素.结论 开(牙合)患者正畸治疗后前牙直立伴随下前牙牙槽骨高度伸长,是前牙覆(牙合)关系建立的重要影响因素.Objective The purpose of this study is to investigate the changes of dentofacial skeleton after orthodontic treatment in anterior open bite patients,and explore their influence on anterior overbite.Methods The sample comprised 50 anterior open bite patients with 37 premolar extraction-treated sample and 13 non-extraction-treated sample.The pre-treatment and post treatment cephalograms were measured.Twenty-eight measurements were constructed.Pre-treatment and posttreatment variables were compared using paired t-test.The changes of variables between two groups were compared using independent t-test.Stepwise multiple 1inear regression was used to screen variables that could affect the change of overbite.Results After orthodontic treatment,the upper and lower incisors were significantly retracted [U1-NA:(-2.43±3.86) mm,P＜0.001;U1/NA:-8.82° ±9.53°,P＜0.001;L1/NB:-6.12°±6.82°,P＜0.001;U1/L1:14.40°±12.17°,P＜0.001] with a greater height of lower alveolus [(1.89± 2.43) mm,P＜0.01].There was no significant difference between the premolar extraction-treated group and the non-extraction-treated group.Stepwise multiple linear regression showed that the change of anterior overbite was affected by the change of upper incisor inclination and lower alveolar height.Conclusions Retraction of incisors and elongation of lower alveolar height were observed following orthodontic treatment and affected the overbite in anterior open bite patients.137-412