骨性Ⅰ类错青少年减数矫治后口咽气道变化的锥形束CT分析

Three-dimensional changes of oropharyngeal airway after orthodontic extraction treatment in skeletal class Ⅰ adolescents

目的探讨减数矫治对青少年上气道形态的影响,为正畸临床矫治提供参考。方法根据随机数字表法随机选取2016年1月至2019年12月就诊于第四军医大学口腔医学院口腔正畸科并行全口直丝弓矫治的骨性Ⅰ类错青少年患者30例,其中男性13例,女性17例,年龄(13.7±1.5)岁(12.2~15.7岁)。所有患者均减数4颗第一前磨牙后在非最大支抗(非种植体支抗或口外弓)下内收上下颌前牙。获取患者减数矫治前后锥形束CT,三维重建上气道模型,测量口咽气道容积和截面积相关测量指标,生成头颅侧位截面并测量牙颌和舌骨位置相关测量指标。比较矫治前后差异,并对口咽气道容积或截面积相关指标变化量与牙颌指标、舌骨位置相关指标变化量进行相关性检验。结果矫治后腭咽气道容积、舌咽气道容积、口咽气道总容积和最小横截面积比矫治前分别增大632(558)、758(549)、1454(955)mm3和14(29)mm2,矫治前后差异均有统计学意义(P<0.05);且口咽气道最小横截面积多位于舌咽部。矫治后悬雍垂尖处气道横截面积及最大前后径分别比矫治前减小(4±10)mm2和(0.4±0.8)mm,矫治前后差异均有统计学意义(P<0.05);但该处最大侧方径的矫治前后差异无统计学意义(P>0.05),矫治后悬雍垂尖处气道最大前后径与最大侧方径的比值[0.535(0.047)]显著小于矫治前[0.589(0.034)](P<0.05)。悬雍垂尖处气道横截面积变化量与下颌中切牙唇倾度变化量、UI-FHp距[上中切牙点(UI点)到过蝶鞍点的眶耳平面垂线(FHp)的距离]变化量和LI-FHp距[下中切牙点(LI点)到过蝶鞍点的眶耳平面垂线(FHp)的距离]变化量均呈正相关(P<0.05)。结论非最大支抗下减数矫治对骨性Ⅰ类错青少年口咽气道的影响总体较小,但可在一定程度上改变气道形态,且悬雍垂尖处气道横截面积的变化与前牙内收量正相关。

Objective To explore the effect of extraction on upper airway in skeletal classⅠadolescents.Methods According to random number table method,30 skeletal classⅠteenagers who underwent orthodontic straight wire treatment were selected randomly in Department of Orthodontics,School of Stomatology,The Fourth Military Medical University between January 2016 and December 2019.There were 13 males and 17 females,aged(13.7±1.5)years(12.2-15.7 years).In all patients,four first premolars were removed and the upper and lower anterior teeth were retracted under non-maximal anchorage(non-implant anchorage or face bow).The cone-beam CT(CBCT)data before and after orthodontic extraction treatments were studied.The three-dimensional model of the upper airway was reconstructed and segmented,and the relevant indexes of oropharyngeal volume and cross-sectional area were measured.Cephalograms was generated to measure tooth-jaw indexes and hyoid position.The changes of each index before and after orthodontic treatment were compared.The correlation between the changes in the volume or sectional area of the oropharyngeal airway and the changes in the dental and maxillary indexes and the hyoid position was tested.Results Compared with those before treatment,palatopharyngeal volume,glossopharyngeal volume,oropharyngeal total volume,and minimum transection area increased by 632(558)mm3,758(549)mm3,1454(955)mm3 and 14(29)mm2 respectively,and statistically significant differences were found(P<0.05).The minimum oropharyngeal area was mostly located in the glossopharynx.The cross-sectional area and the maximum anterior-posterior diameter of uvula tip decreased by(4±10)mm2 and(0.4±0.8)mm respectively,and the difference was statistically significant(P<0.05).There was no significant difference in the maximum lateral diameter before and after treatment(P>0.05).The ratio of the maximum antero-posterior diameter to the maximum lateral diameter at the uvula tip decreased from 0.589(0.034)before treatment to 0.535(0.047)after treatment(P<0.05),indicating that its shape tends to be more elliptic after treatment.In addition,the change of cross-sectional area at the apex of uvula was positively correlated with the changes of mandibular central incisor lip inclination and the distances from the upper and lower central incisor points to the Frankfort plane perpendicular to the sella point(UI-FHp and LI-FHp)(P<0.05).Conclusions The impact of orthodontic extraction treatment on oropharyngeal airway was generally small in skeletal classⅠadolescents.However,it could change the shape of the airway to some extent.The change of airway cross-sectional area at the uvula tip was positively correlated with the retraction of anterior teeth.