Sun J W, Tang R, Gao J, Li Y M
Department of Orthodontics, School of Stomatology, The Fourth Military Medical University & State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Xi'an 710032, China.
Zhonghua Kou Qiang Yi Xue Za Zhi. 2021 Mar 9;56(3):256-262. doi: 10.3760/cma.j.cn112144-20200430-00241.
To explore the effect of extraction on upper airway in skeletal class Ⅰ adolescents. According to random number table method, 30 skeletal class Ⅰteenagers 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. Compared with those before treatment, palatopharyngeal volume, glossopharyngeal volume, oropharyngeal total volume, and minimum transection area increased by 632 (558) mm, 758 (549) mm, 1 454 (955) mm and 14 (29) mm respectively, and statistically significant differences were found (<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) mm and (0.4±0.8) mm respectively, and the difference was statistically significant (<0.05). There was no significant difference in the maximum lateral diameter before and after treatment (>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 (<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) (<0.05). The impact of orthodontic extraction treatment on oropharyngeal airway was generally small in skeletal class Ⅰ adolescents. 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.
探讨拔牙矫治对恒牙早期安氏Ⅰ类青少年上气道的影响。采用随机数字表法，选取2016年1月至2019年12月在第四军医大学口腔医院正畸科就诊的恒牙早期安氏Ⅰ类青少年患者30例，其中男性13例，女性17例，年龄（13.7±1.5）岁（12.2～15.7岁）。所有患者均拔除4个第一前磨牙，采用非种植支抗（非种植支抗或口外弓）内收上下前牙。研究正畸拔牙治疗前后的锥形束CT（CBCT）数据，重建并分割上气道三维模型，测量口咽腔容积和截面积等相关指标；拍摄头颅定位侧位片测量牙颌指标及舌骨位置，比较正畸治疗前后各指标的变化，并对口咽气道容积或截面积变化与牙颌指标及舌骨位置变化的相关性进行检验。结果显示，与治疗前比较，腭咽腔容积、舌咽腔容积、口咽腔总体积及最小截面积分别增加632（558）mm³、758（549）mm³、1 454（955）mm³和14（29）mm²，差异有统计学意义（P<0.05）。口咽腔最小截面积多位于舌咽平面。悬雍垂尖截面积及前后径最大值分别减小（4±10）mm和（0.4±0.8）mm，差异有统计学意义（P<0.05），左右径最大值治疗前后差异无统计学意义（P>0.05）。悬雍垂尖前后径与左右径比值由治疗前的0.589（0.034）降至治疗后的0.535（0.047），差异有统计学意义（P<0.05），提示治疗后悬雍垂形态更趋于椭圆形。此外，悬雍垂尖截面积变化与下颌中切牙唇倾度及上下中切牙点至垂直于蝶鞍点的Frankfort平面距离（UI-FHp、LI-FHp）变化呈正相关（P<0.05）。结论：恒牙早期安氏Ⅰ类青少年正畸拔牙治疗对其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，悬雍垂尖截面积变化与前牙内收量呈正相关。
