Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, China.
National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, Beijing, China.
Eur J Orthod. 2022 Mar 30;44(2):155-162. doi: 10.1093/ejo/cjab034.
Quantification and visualization of the location and magnitude of facial asymmetry is important for diagnosis and treatment planning. The objective of this study was to analyze the asymmetric features of the face for skeletal Class III patients using spatially-dense geometric morphometrics.
Three-dimensional facial images were obtained for 86 skeletal Class III patients. About 7160 uniformly sampled quasi-landmarks were automatically identified on each face using template mapping technique. The pointwise surface-to-surface distance between original and mirror face was measured and visualized for the whole face after robust Procrustes superimposition. The degree of overall asymmetry in an individual was scored using a root-mean-squared-error. Automatic partitioning of the face was obtained, and the severity of the asymmetry compared among seven facial regions.
Facial asymmetry was mainly located on, but not limited to, the lower two-thirds of the face in skeletal Class III patients. The lower cheek and nose asymmetry were detected to have more extensive and of a greater magnitude of asymmetry than other facial anatomical regions but with various individual variations. The overall facial asymmetry index and the regional facial asymmetry indices were higher in males and patients with chin deviation.
Soft tissue asymmetry is predominately presented in the lower-third of the face in skeletal Class III patients and with various variations on other facial anatomical regions. Morphometric techniques and computer intensive analysis have allowed sophisticated quantification and visualization of the pointwise asymmetry on the full face.
对面部不对称的位置和程度进行量化和可视化对于诊断和治疗计划非常重要。本研究的目的是使用空间密集型几何形态计量学分析骨骼 III 类患者的面部不对称特征。
对 86 名骨骼 III 类患者的三维面部图像进行了采集。使用模板映射技术，在每张脸上自动识别了大约 7160 个均匀采样的准地标。在稳健的 Procrustes 叠加后，测量和可视化了原始和镜像脸之间的逐点表面到表面距离。使用均方根误差对个体的整体不对称程度进行评分。获得了面部的自动分区，并比较了七个面部区域之间的不对称严重程度。
面部不对称主要位于骨骼 III 类患者的下半部，但不限于下半部。下脸颊和鼻子的不对称被检测到具有更广泛和更大程度的不对称，但存在各种个体差异。男性和颏部偏斜患者的整体面部不对称指数和区域面部不对称指数更高。
在骨骼 III 类患者中，软组织不对称主要表现为面部下半部，其他面部解剖区域也存在各种变化。形态计量技术和计算机密集型分析允许对面部全面的逐点不对称进行复杂的量化和可视化。
