Nur Rahime Burcu, Çakan Derya Germeç, Arun Tülin
Teaching assistant, Department of Orthodontics, Faculty of Dentistry, Yeditepe University, Istanbul, Turkey.
Associate professor, Department of Orthodontics, Faculty of Dentistry, Yeditepe University, Istanbul, Turkey.
Am J Orthod Dentofacial Orthop. 2016 Feb;149(2):225-37. doi: 10.1016/j.ajodo.2015.07.038.
The purposes of this study were to (1) evaluate facial asymmetry 3 dimensionally using cone-beam computed tomography (CBCT) and (2) compare the right and left facial hard and soft tissues volumetrically and their interferences on each other.
The CBCT data of 49 asymmetric (soft tissue menton deviation, ≥4 mm; distance from the facial midline) (mean age, 19.9 ± 5.6 years) and 39 symmetric patients (soft tissue menton deviation, <4 mm) (mean age, 17.8 ± 5.5 years) were exported to the MIMICS software program (version 13.0; Materialise, Leuven, Belgium). Linear, surface distance, angular, volumetric, and surface area measurements were performed 3 dimensionally to assess and compare intragroup and intergroup differences.
In the asymmetry group, linear measurements such as ramus height, mandibular effective and corpus length, and absolute mandibular volumetric measurements were significantly decreased (P <0.001), whereas facial mandibular, and soft and hard tissue volumetric measurements made on 3-dimensional images, and linear measurements on 2-dimensional images were increased (P <0.001) on the deviation side.
Facial hard and soft tissue asymmetries can be precisely quantified using CBCT. However, especially in the gonial region where the surface topography shows alterations caused by asymmetry, many anatomic landmarks should be chosen for the assessment of asymmetry. At the gonial level, the compensation of the soft tissues for the hard tissues was found on 2-dimensional images; nevertheless, 3-dimensional right and left volumetric soft tissue evaluations provide evidence for asymmetry.
本研究的目的是：（1）使用锥形束计算机断层扫描（CBCT）对面部不对称进行三维评估；（2）对面部左右软硬组织进行体积比较以及它们之间的相互干扰情况。
将49例不对称患者（软组织颏下点偏移≥4mm；距面部中线距离）（平均年龄19.9±5.6岁）和39例对称患者（软组织颏下点偏移<4mm）（平均年龄17.8±5.5岁）的CBCT数据导入MIMICS软件程序（版本13.0；Materialise，鲁汶，比利时）。进行三维线性、表面距离、角度、体积和表面积测量，以评估和比较组内及组间差异。
在不对称组中，诸如升支高度、下颌有效长度和体部长度等线性测量值以及下颌绝对体积测量值显著降低（P<0.001），而在三维图像上进行的面部下颌以及软硬组织体积测量值，以及在二维图像上的线性测量值在偏移侧增加（P<0.001）。
使用CBCT可以精确量化面部软硬组织不对称。然而，特别是在角区，其表面形态因不对称而发生改变，在评估不对称时应选择许多解剖标志点。在角区水平，在二维图像上发现软组织对硬组织有代偿情况；尽管如此，左右软组织体积的三维评估为不对称提供了证据。
