Lee Sang Woo, Cho Jeongmok, Kim Kikap, Ahn Seung Hyun
DA Plastic Surgery Clinic, 8F, W Tower, 54, Seocho-daero 77-gil, Seocho-gu, Seoul, Republic of Korea.
Banobagi Plastic Surgery Clinic, Seoul, Republic of Korea.
Aesthetic Plast Surg. 2017 Jun;41(3):641-649. doi: 10.1007/s00266-017-0838-7. Epub 2017 Mar 24.
Orthognathic surgery has become more popular to slenderize a wide lower face and to improve facial esthetics in Asian patients with normal occlusion. Clockwise rotation (CR) of the maxillomandibular complex (MMC) steepens the mandibular plane. This study performed a quantitative analysis on the influence of CR on slenderness of the lower face from the frontal view.
This retrospective study included 36 female patients with Angle Class I occlusion and skeletal Class III pattern. The subjects underwent CR of the MMC without perioperative orthodontic treatment and change in the occlusion only for the purpose of esthetic improvement. Linear and angular variables were measured on a cephalogram and three-dimensional computed tomography (3D CT) obtained before and at least 6 months after surgery. Data were analyzed using paired t tests and Spearman correlations. Univariate regression analysis was used to predict the postoperative change according to the amount of posterior impaction.
The mean posterior impaction was 3.81 mm. All mandibular plane angle (MPA) measurements were increased (ranged from 5.69° to 13.12°, p < 0.001), exhibiting a significant correlation with the amount of posterior impaction. Bigonial width measurements were decreased after surgery (ranged from 4.97 to 5.51 mm, p < 0.001). Among the MPAs derived from the 3D CT, the coronal projection from the frontal view exhibited a discrepancy between right and left side.
The changes in linear and angular measurements in this study indicate that the lower face becomes narrower and more slender as the MMC rotates in a clockwise direction. Orthognathic surgery with CR has the advantage of increasing the MPAs and obtaining natural soft tissue contouring while minimizing the amount of bone resection.
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正颌手术在亚洲咬合正常的患者中越来越受欢迎，用于瘦脸并改善面部美观。上颌下颌复合体（MMC）的顺时针旋转（CR）会使下颌平面变陡。本研究对CR从正面观对下脸细长程度的影响进行了定量分析。
这项回顾性研究纳入了36例安氏I类咬合和骨骼III类模式的女性患者。受试者接受了MMC的CR，未进行围手术期正畸治疗，且仅为改善美观而改变咬合。在术前和术后至少6个月获得的头颅侧位片和三维计算机断层扫描（3D CT）上测量线性和角度变量。数据采用配对t检验和Spearman相关性分析。单因素回归分析用于根据后徙量预测术后变化。
平均后徙量为3.81毫米。所有下颌平面角（MPA）测量值均增加（范围为5.69°至13.12°，p < 0.001），与后徙量呈显著相关性。术后下颌角间宽度测量值减小（范围为4.97至5.51毫米，p < 0.001）。在从3D CT得出的MPA中，正面观的冠状投影在左右侧存在差异。
本研究中线性和角度测量的变化表明，随着MMC顺时针旋转，下脸变得更窄、更细长。采用CR的正颌手术具有增加MPA和获得自然软组织轮廓同时最小化骨切除量的优点。
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