正畸治疗中前磨牙区开的原因分析

Orthodontic treatment premolar-open bite of analysis of causes

对440例非开的错患者采用标准直丝弓矫正技术,正畸治疗进入正畸第三阶段前观察前磨牙区的覆情况。有41例患者出现了前磨牙区的Ⅰ度开。其中男性20例,女性21例,男女之间差异无统计学意义。拔牙矫治患者前磨牙区开的发生率明显高于非拔牙矫治患者,两者之间差异有显著性(P<0.01)。发生开的原因从高到低依次为:前磨牙向拔牙间隙侧倾斜,前磨牙区托槽定位不佳,磨牙升高,不良口腔习惯。因此对于拔牙矫治患者,在关闭间隙过程中要使用硬丝轻力,争取牙的整体移动;前磨牙区的托槽定位要兼顾尖牙和磨牙的临床冠高度;颌间牵引要慎用,使用颌间牵引过程中要用轻力及加强磨牙支抗;要加强口腔卫生宣教,防止患者发生不良的口腔习惯。

Occurrence of premolar area open bite during orthodontic treatment will result in extended corrective course and failure of Spee curve and molar relationship correction,leading to reduction of bite force.440 clinically non-open bite malocclusion patients were recruited in this study.All the patients were treated with standard straight wire technique.Degrees of overbite in premolar area were recorded just before entering the orthodontics phase III treatment.Ⅰ° open bite in premolar area was observed in 41 patients（20 males and 21 females）.There was no statistical significance difference between different genders.Cases with history of extraction of premolar had higher incidence of open bite than those without history of extraction.The difference was significant（P0.01）.The reasons of open bite occurrence in order from highest to lowest were：Tilting of neighboring premolars towards extraction space,poor bracket positioning in premolar areas,hyperocclusion of molars,bad oral habits.Accordingly,precautions should be taken during orthodontic treatment as follows：Applying light force with hard wire during gap closing to achieve whole body movement of teeth;Bracket positioning on premolar should take clinical crown height of both cuspids and molars into consideration;Intermaxillary traction should be used with caution;Applying light force and strengthening molar anchorage in the course of intermaxillary traction;Enhancing oral health education for patients to prevent and correct bad oral habits.