Supmaneenukul Yannapat, Khemla Chinnachote, Parakonthun Kulthida
Residency Training in Orthodontics, Orthodontic Division, Department of Pedodontics and Preventive Dentistry, Faculty of Dentistry, Srinakharinwirot University, Bangkok, 10110, Thailand.
Oral Surgery Section, Department of Oral Surgery and Oral Medicine, Faculty of Dentistry, Srinakharinwirot University, Bangkok, 10110, Thailand.
Heliyon. 2024 Mar 7;10(6):e27720. doi: 10.1016/j.heliyon.2024.e27720. eCollection 2024 Mar 30.
This study aimed to evaluate bilateral soft tissue, hard and soft-tissue thickness at various anatomical levels in patients with facial asymmetries. Moreover, we attempted to find out correlation between soft-tissue compensation and severity of asymmetry by using cone-beam computed tomography (CBCT) combined with 3D facial photographs.
Based on menton deviation (MD), twenty-four subjects were divided into: mild-asymmetry group (n=12) and moderate-to-severe-asymmetry group (n = 12). CBCT images were superimposed with 3D facial photographs. Distance from the midsagittal plane to the outermost point of soft-tissue and hard-tissue were measured and calculated soft-tissue thickness. Comparison of soft-tissue thickness between deviated and contralateral side at any anatomical levels were performed within group, and correlation between bilateral soft-tissue thickness subtractions (soft-tissue compensation) and MD values was evaluated.
Within group, Soft- and hard-tissue distances were greater in deviated side than contralateral side at any levels. In moderate-to-severe group, significant differences were found at gonion and body of mandible level, whereas soft-tissue thickness was only found to be higher on deviated side at the level of mandibular ramus. Soft tissue compensation was negatively correlated with MD value at level of mandibular ramus (R = -0.5, P < 0.05).
Asymmetry was found to be larger in the lower third of the face and was notably remarkable in the moderate-to-severe group. Soft-tissue thickness was thicker on the deviated side of the mandibular ramus. Thus, the soft-tissue compensation seems to be minimized in patients with more severe asymmetry.
本研究旨在评估面部不对称患者不同解剖层面的双侧软组织、硬组织及软硬组织厚度。此外，我们试图通过锥形束计算机断层扫描（CBCT）结合三维面部照片，找出软组织代偿与不对称严重程度之间的相关性。
根据颏点偏移（MD），将24名受试者分为：轻度不对称组（n = 12）和中重度不对称组（n = 12）。CBCT图像与三维面部照片进行叠加。测量从中矢状面到软组织和硬组织最外侧点的距离，并计算软组织厚度。在组内对任何解剖层面偏离侧与对侧的软组织厚度进行比较，并评估双侧软组织厚度差值（软组织代偿）与MD值之间的相关性。
在组内，任何层面的偏离侧软组织和硬组织距离均大于对侧。在中重度组中，在下颌角和下颌体水平发现显著差异，而仅在下颌升支水平发现偏离侧的软组织厚度更高。在下颌升支水平，软组织代偿与MD值呈负相关（R = -0.5，P < 0.05）。
发现面部下三分之一的不对称更大，在中重度组中尤为明显。下颌升支偏离侧的软组织厚度更厚。因此，在不对称更严重的患者中，软组织代偿似乎最小化。
