Lee Sung-Tak, Mori Yoshihide, Minami Katsuhiro, An Chang-Hyeon, Park Jin-Woo, Kwon Tae-Geon
Center for Orthognathic surgery, Department of Oral and Maxillofacial Surgery, Kyungpook National University School of Dentistry, Daegu, Korea.
J Oral Maxillofac Surg. 2013 Sep;71(9):1577-87. doi: 10.1016/j.joms.2013.04.008. Epub 2013 Jun 22.
The purpose of the present study was to investigate whether asymmetric mandibular prognathism accompanies a fundamental difference in soft tissue thickness and whether asymmetric mandibular setback surgery would influence the contour and thickness of the soft tissue of the chin.
The present retrospective study included skeletal class III patients with significant mandibular chin deviation greater than 6 mm at the pogonion, who had undergone cone-beam computed tomography before and 6 months after surgery during a 2-year period. The predictor variables were timing (pre- and postoperatively) and side (asymmetric vs contralateral). The outcome measures were the hard and soft tissue contours and soft tissue thickness of the chin at the infradentale, B-point, and pogonion level evaluated with reformatted computed tomography images. The study variables were statistically compared using regression model and correlation analysis.
The present study consisted of 20 patients (10 males and 10 females; average age 20.2 years; range, 18 to 25). Preoperatively, the chin deviation side showed a more prominent hard and soft tissue outline but had a thinner soft tissue thickness, which camouflaged the hard tissue asymmetry. After surgery, the hard and soft tissue outline was greatly improved, and the soft tissue thickness had become nearly symmetric. Most of the soft tissue thickness changes correlated negatively with the hard tissue changes.
Asymmetric mandibular prognathism accompanied the 3-dimensional soft tissue contour and thickness asymmetry. Because the soft tissue responds favorably after skeletal surgery, the correction of 3-dimensional asymmetry of bone should be emphasized in patients with asymmetric mandibular prognathism.
本研究旨在调查下颌不对称前突是否伴随着软组织厚度的根本差异，以及下颌不对称后退手术是否会影响颏部软组织的轮廓和厚度。
本回顾性研究纳入了骨骼Ⅲ类患者，这些患者在颏前点处下颌颏部偏差大于6mm，在2年期间内于手术前和术后6个月接受了锥形束计算机断层扫描。预测变量为时间（术前和术后）和侧别（不对称侧与对侧）。通过重新格式化的计算机断层扫描图像评估的结果指标为颏部在龈下、B点和颏前点水平的硬组织和软组织轮廓以及软组织厚度。使用回归模型和相关性分析对研究变量进行统计学比较。
本研究包括20例患者（10例男性和10例女性；平均年龄20.2岁；范围18至25岁）。术前，颏部偏差侧显示出更突出的硬组织和软组织轮廓，但软组织厚度较薄，这掩盖了硬组织的不对称性。术后，硬组织和软组织轮廓有了很大改善，软组织厚度几乎变得对称。大多数软组织厚度变化与硬组织变化呈负相关。
下颌不对称前突伴随着三维软组织轮廓和厚度的不对称。由于骨骼手术后软组织反应良好，对于下颌不对称前突患者，应强调纠正骨的三维不对称。
