Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. K Ueki), Division of Medicine, Interdisciplinary Graduate School, University of Yamanashi, 1110 Shimokato, Chuo-shi, Yamanashi, 409-3898, Japan.
Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. K Ueki), Division of Medicine, Interdisciplinary Graduate School, University of Yamanashi, 1110 Shimokato, Chuo-shi, Yamanashi, 409-3898, Japan.
J Craniomaxillofac Surg. 2018 Dec;46(12):2103-2107. doi: 10.1016/j.jcms.2018.10.010. Epub 2018 Oct 22.
The purpose of this study was to examine the relationship between occlusal force and condylar morphology in class II and III after sagittal split ramus osteotomy (SSRO) with Le Fort I osteotomy.
The subjects were 42 female patients who underwent bi-maxillary surgery, and were divided into 2 groups (21 class II and 21 class III cases). They were selected randomly from among patients that underwent surgery from 2012 to 2017. Condylar height, ramus height, ramus inclination and condylar square were assessed by computed tomography (CT), preoperatively and 1 year postoperatively. Occlusal contact area and occlusal force were measured pre- and 1, 3, 6 and 12 months post-operative.
Condylar height and ramus height of the class II advancement cases decrease more significantly than those of class III. There were no significant differences in time-course changes of occlusal force and area between the class II and III. In the class II cases, occlusal force at 1 and 3 months was significantly lower than the preoperative value (P = 0.0009, P = 0.0002). On the other hand, in class III, occlusal force at 1, 3 and 6 months (P = 0.0038, P = 0.0031, P = 0.0283) was significantly lower than the preoperative value.
This study suggested that occlusal force of the class II advancement cases reached the pre-operative level earlier than that of the class III setback cases, even though condylar height decreased after surgery in the class II cases. However, a correlation between occlusal force change and condylar height reduction after surgery could not be found.
本研究旨在探讨经 Le Fort I 截骨颏成形术的矢状劈开下颌骨截骨术（SSRO）后 II 类和 III 类错（牙合）患者的（牙合）力与髁突形态之间的关系。
本研究纳入了 42 名接受双颌手术的女性患者，根据术前是否存在 II 类或 III 类错（牙合），将患者分为 2 组（21 名 II 类错（牙合）患者和 21 名 III 类错（牙合）患者）。所有患者均于 2012 年至 2017 年期间接受手术治疗。通过 CT 评估术前和术后 1 年时髁突高度、下颌升支高度、下颌升支倾斜度和髁突四方区的情况。在术前和术后 1、3、6 和 12 个月时测量（牙合）接触面积和（牙合）力。
与 III 类错（牙合）后缩病例相比，II 类错（牙合）前突病例的髁突高度和下颌升支高度下降更为显著。II 类和 III 类错（牙合）患者（牙合）力和（牙合）接触面积的时间变化无显著差异。在 II 类错（牙合）前突病例中，术后 1 个月和 3 个月时的（牙合）力显著低于术前值（P=0.0009，P=0.0002）。而在 III 类错（牙合）后缩病例中，术后 1、3 和 6 个月时的（牙合）力显著低于术前值（P=0.0038，P=0.0031，P=0.0283）。
本研究表明，尽管 II 类错（牙合）前突病例在术后髁突高度下降，但与 III 类错（牙合）后缩病例相比，其（牙合）力更早达到术前水平。然而，术后（牙合）力变化与髁突高度下降之间的相关性并未得到证实。
