[Maxillary and upper airway changes immediately after mini-screw assisted rapid maxillary expansion in class Ⅲ patients].

Objective: To assess maxillary sagittal and vertical as well as upper airway changes immediately after mini-screw assisted rapid maxillary expansion (MARME) in class Ⅲ patients. Method: A consecutive sample of 48 class Ⅲ patients with maxillary transverse deficiency who visited the Department of Orthodontics, School & Hospital of Stomatology, Wuhan University between January 2013 and March 2023 was retrospectively collected. The sample was comprised of 24 growing patients (cervical vertebra maturation, CVM 1-4) and 24 nongrowing patients (CVM 5-6). Cone-beam CT scans before (T0) and immediately after MARME (T1) were imported into Dolphin Imaging software, and then voxel-based superimposition was conducted on the basis of the anterior cranial base. Sagittal and vertical changes of the maxillary landmarks (A, ANS, PNS, UI and Spr), as well as upper airway changes after MARME were measured on multiplanar reconstruction views. Wilcoxon signed-rank test was employed to analyze the changes after MARME. Mann-Whitney U test was employed to compare the changes between growing and non-growing patients. Results: Some class Ⅲ patients exhibited significant maxillary sagittal and vertical changes immediately after MARME. The amount of changes in midpalatal suture was 4.03 (2.99, 4.87) mm in growing patients, significantly larger than that in non-growing patients [2.27 (1.49, 3.64) mm] (U=3.18, P=0.001). In growing class Ⅲ patients, the forward changes of A, ANS, PNS, UI and Spr were 0.35 (0.06, 0.80), 0.48 (0.11, 0.88), 0.48 (0.13, 0.99), 0.53 (-0.33, 1.04) and 0.40 (0.03, 0.69) mm, respectively. Vertically, the downward changes of A, ANS, PNS, UI and Spr were 1.45 (0.99, 2.13), 1.18 (0.61, 1.95), 1.30 (0.91, 1.96), 1.20 (0.71, 1.83) and 1.30 (0.81, 1.73) mm, respectively. All changes were significantly different from 0 after treatment (P<0.05). In nongrowing patients, PNS moved forward by 0.18 (-0.08, 0.39) mm while other sagittal changes were statistically insignificant (P>0.05); vertically, the downward changes of A, ANS, PNS, UI and Spr were 0.90 (0.51, 1.39), 0.73 (0.41, 1.21), 0.70 (0.55, 1.08), 0.60 (0.36, 1.19) and 0.70 (0.55, 1.23) mm, respectively. Significant immediate increase of the nasopharynx volume and nasal width was obtained in both groups (P<0.05), and the changes of oropharynx volume and minimum cross-sectional area (MCA) presented as statistically insignificant (P>0.05). Conclusions: For growing class Ⅲ patients, besides transverse expansion, significant forward and downward changes of maxilla were obtained immediately after MARME. For non-growing patients, significant downward changes were observed, while sagittal changes were negligible. The nasopharynx volume increased in both growing and nongrowing class Ⅲ patients immediately after MARME, whereas, the changes of oropharynx volume and MCA presented as statistically insignificant.目的： 通过锥形束CT探讨种植体支抗辅助上颌快速扩弓后Ⅲ类错（牙合）患者上颌骨矢状向和垂直向即刻改变及上气道的变化，以期为临床提供参考。 方法： 回顾性收集2013年1月至2023年3月于武汉大学口腔医（学）院正畸一科就诊的伴上颌横向发育不足的48例Ⅲ类错（牙合）患者锥形束CT，其中生长期组（颈椎成熟度1~4期）24例，非生长期组（颈椎成熟度5~6期）24例。将扩弓前（T0期）及扩弓后即刻（T1期）锥形束CT数据导入Dolphin Imaging软件，以前颅底区域为基准进行三维体素重叠。确定上颌骨标志点：上牙槽座点（A点）、前鼻棘点（ANS点）、后鼻棘点（PNS点）、上颌中切牙点（UI点）和上牙槽缘点（Spr点）。在重叠后的多平面重建图中，测量扩弓前后上颌骨相同标志点间距离的矢状向和垂直向投影长度，分别代表该标志点矢状向和垂直向变化量，以及上气道测量项目的变化量。采用Wilcoxon符号秩检验分析扩弓变化量与0的差异，采用独立样本Mann-Whitney U检验分析生长期组与非生长期组扩弓变化量的差异。 结果： 扩弓后即刻部分Ⅲ类错（牙合）患者上颌骨发生一定的矢状向及垂直向移位。生长期组腭中缝变化量为4.03（2.99，4.87）mm，显著大于非生长期组［2.27（1.49，3.64）mm］（U=3.18，P=0.001）。生长期组A点、ANS点、PNS点、UI点和Spr点矢状向变化量分别为前移0.35（0.06，0.80）、0.48（0.11，0.88）、0.48（0.13，0.99）、0.53（-0.33，1.04）和0.40（0.03，0.69）mm，垂直向变化量分别为下移1.45（0.99，2.13）、1.18（0.61，1.95）、1.30（0.91，1.96）、1.20（0.71，1.83）和1.30（0.81，1.73）mm，与0相比差异均有统计学意义（P<0.05）。非生长期组PNS点前移0.18（-0.08，0.39）mm，A点、ANS点、UI点和Spr点矢状向变化量与0相比差异均无统计学意义（P>0.05），垂直向变化量A点、ANS点、PNS点、UI点和Spr点分别为下移0.90（0.51，1.39）、0.73（0.41，1.21）、0.70（0.55，1.08）、0.60（0.36，1.19）和0.70（0.55，1.23）mm。扩弓前后两组鼻腔宽度和鼻咽容积变化量与0相比差异均有统计学意义（P<0.05），口咽容积及口咽最小横截面积变化量与0相比差异均无统计学意义（P>0.05）。 结论： 种植体支抗辅助上颌快速扩弓后生长期Ⅲ类错（牙合）患者上颌骨除发生横向变化外，还发生较显著的向前及向下的变化；非生长期Ⅲ类错（牙合）患者上颌骨无明显的矢状向变化，但伴较明显的垂直向变化。扩弓后即刻生长期及非生长期Ⅲ类错（牙合）患者鼻咽容积均有所增大，口咽容积及口咽最小横截面积均无明显改变。.