Department of Orthodontics, NHC Research Center of Engineering and Technology for Computerized Dentistry, Peking University School and Hospital of Stomatology, Beijing, China.
Department of Orthodontics, NHC Research Center of Engineering and Technology for Computerized Dentistry, Peking University School and Hospital of Stomatology, Beijing, China; National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory for Digital Stomatology & Research Center of Engineering and Technology for Computerized Dentistry Ministry of Health, Beijing, China.
Am J Orthod Dentofacial Orthop. 2023 Nov;164(5):728-740. doi: 10.1016/j.ajodo.2023.04.023. Epub 2023 Jul 28.
This study aimed to compare postsurgical stability between conventional (CSA) and surgery-first (SFA) approaches and investigate its prognostic factors in patients with a skeletal Class Ⅲ extraction.
Twenty and 19 patients treated with LeFort I osteotomy and bilateral sagittal split ramus osteotomy (BSSRO) with premolar extraction were enrolled in SFA and CSA groups, respectively. Serial cone-beam computed tomography images obtained before surgery, immediately after surgery (T1), 3 months after surgery, and 12 months after surgery were used for 3-dimensional quantitative analysis. The condyle was segmented for analyzing volumetric changes. Repeated measures analysis of variance, independent t test, and chi-square test were used to compare time-course and intergroup differences. Pearson and Kendall correlation and multivariate linear regression analyses were used to explore prognostic factors affecting skeletal stability.
In both CSA and SFA, postsurgical relapse mainly occurred in the mandible sagittal and vertical dimensions and during the first 3 months after surgery. Stability in SFA was significantly less than that in CSA. Intraoperatively, inferolateral condylar displacement with proximal segment inwards, clockwise rotation, and return movements after surgery were observed regardless of the treatment approach. The condylar volume remained stable over time. Multivariate regression analysis showed that posterior vertical dimension (VD) at T1 (-1.63 mm), surgical amount of mandibular setback (-10.33 mm), surgical condylar downwards displacement (-1.28 mm), and anterior overjet at T1 (6.43 mm) were the most important predictors of early mandibular relapse (r = 0.593).
The risk of early relapse could be reduced by controlling the anterior, middle, and posterior constraints provided by the prediction model.
本研究旨在比较传统（CSA）和先手术（SFA）方法在接受骨骼 III 类拔牙的患者中的术后稳定性，并探讨其预后因素。
20 名和 19 名接受 LeFort I 截骨术和双侧矢状劈开下颌升支截骨术（BSSRO）伴前磨牙拔除的患者分别纳入 SFA 和 CSA 组。使用术前、术后即刻（T1）、术后 3 个月和术后 12 个月的锥形束 CT 图像进行三维定量分析。对髁突进行分割以分析容积变化。采用重复测量方差分析、独立 t 检验和卡方检验比较时间过程和组间差异。采用 Pearson 和 Kendall 相关分析和多元线性回归分析探讨影响骨骼稳定性的预后因素。
在 CSA 和 SFA 中，术后复发主要发生在下颌矢状和垂直方向，并且在术后 3 个月内。SFA 的稳定性明显低于 CSA。术中观察到无论治疗方法如何，髁突均存在向外侧下的移位，近段向内侧，顺时针旋转以及术后的回退运动。髁突体积随时间保持稳定。多元回归分析显示 T1 时的后垂直距离（VD）（-1.63mm）、下颌后退手术量（-10.33mm）、髁突向下手术位移（-1.28mm）和 T1 时的前覆颌（6.43mm）是早期下颌复发的最重要预测因素（r=0.593）。
通过控制预测模型提供的前、中、后约束，可以降低早期复发的风险。
