Department of Oral Development and Orthodontics, Oulu University Hospital, Oulu, Finland.
Department of Oral Development and Orthodontics, Unit of Oral Health Sciences, Faculty of Medicine, University of Oulu, Oulu, Finland.
Eur J Orthod. 2023 Jul 31;45(4):396-407. doi: 10.1093/ejo/cjad012.
This prospective, population-based cohort study aimed to investigate the development of facial asymmetry up to 6 years of age using a three-dimensional (3D) soft tissue imaging method in a normal population. In addition, the study sought to identify potential predisposing factors to facial asymmetry.
A total of 102 newborns were enrolled in the study at birth. 3D stereophotogrammetric images of the head and face were analysed at the ages of 12 months (T1), 3 years (T2), and 6 years (T3). The surface-based analysis involved the calculation of the average distance (mm) and the symmetry percentage (%) between the original and mirrored surfaces. For landmark-based analysis, the distance of facial landmarks to the facial midline was examined.
The final analysis included 70 (68.6%) subjects. Surface-based analysis showed a significant improvement of facial symmetry from T1 to T3 in all facial areas. Landmark-based analysis showed that upper facial landmarks were located, on average, slightly on the left and lower facial landmarks slightly on the right in relation to the facial midline (P < 0.001).
The size of the study population was limited. Facial posture may affect the reliability of the results, especially in younger children.
Facial asymmetry is detectable in early childhood and tends to reduce with age in young children. The lower face deviates slightly to the right, and the upper face to the left in relation to the facial midline. Possible predisposing factors for facial asymmetry at the age of 6 years include deformational plagiocephaly, sleeping position, and previous facial asymmetry.
本前瞻性、基于人群的队列研究旨在使用三维（3D）软组织成像方法在正常人群中研究面部不对称的发展情况，直至 6 岁。此外，本研究还试图确定导致面部不对称的潜在诱发因素。
本研究共纳入 102 名新生儿，在出生时即入组。在 12 个月（T1）、3 岁（T2）和 6 岁（T3）时对头面部进行 3D 立体摄影图像分析。基于表面的分析包括计算原始和镜像表面之间的平均距离（mm）和对称百分比（%）。对于基于标志点的分析，检查了面部标志点与面部中线之间的距离。
最终分析纳入 70 名（68.6%）受试者。基于表面的分析显示，所有面部区域的面部对称性均从 T1 到 T3 显著改善。基于标志点的分析显示，与面部中线相比，上脸标志点平均位于左侧，下脸标志点位于右侧（P < 0.001）。
研究人群规模有限。面部姿势可能会影响结果的可靠性，尤其是对于年幼的儿童。
在幼儿期可以检测到面部不对称，并且在年幼的儿童中，面部不对称会随着年龄的增长而逐渐减轻。下脸相对于面部中线稍微向右偏，上脸相对于面部中线稍微向左偏。6 岁时导致面部不对称的可能诱发因素包括变形性斜头畸形、睡眠姿势和以前的面部不对称。
