Macari Anthony T, Hanna Antoine E, Chekie Michelle El
Division of Orthodontics and Dentofacial Orthopedics, Department of Dentofacial Medicine, Faculty of Medicine, American University of Beirut- Lebanon, Beirut, Lebanon.
Clinical associate, Division of Orthodontics and Dentofacial Orthopedics, Department of Dentofacial Medicine, Faculty of Medicine, American University of Beirut- Lebanon, Beirut, Lebanon.
BMC Oral Health. 2025 Apr 29;25(1):660. doi: 10.1186/s12903-025-06054-7.
The alignment of craniofacial structures in three dimensions-transverse, vertical, and sagittal-determines facial esthetics. While skeletal and dental factors influence these outcomes, soft tissue characteristics, especially facial soft tissue (FST) thickness, are increasingly recognized as important. However, few studies have examined the impact of vertical facial divergence on soft tissue variation, particularly in the middle and lower thirds of the face.
This study aimed to evaluate the association between vertical facial divergence and facial soft tissue characteristics of lower and upper thirds in adult patients.
A total of 120 non-growing individuals (60 men, 60 women) with an average age of 27.87 years (range: 18-56) seeking orthodontic treatment were included. Participants were stratified into four groups based on mandibular plane inclination to anterior cranial base (MP/SN): Group 1: MP-SN ≤ 27°, group 2: 27°< MP-SN ≤ 32º, group 3: 32°< MP-SN < 37°, and group 4: MP-SN ≥ 37°. Lateral cephalometric radiographs were used to measure FST thickness in the horizontal plane at specific anatomical landmarks, including the base of the forehead, nose, lips, and chin. Additionally, lip length, chin projection, and angular inclinations were assessed. Group comparisons were performed using one-way ANOVA followed by the post-hoc Benferroni test. The strength of the linear relationship between variables was investigated using the Pearson correlation test. Statistical significance was set at p = 0.05.
Significant differences in facial soft tissue characteristics were observed across groups. Hyperdivergent individuals (Group 4) exhibited significantly (p < 0.001) increased total facial height (TFH), lower facial height (LFH), and longer upper and lower lips compared to hypodivergent individuals (Group 1). Group 4 also had thinner soft tissue (p < 0.001) at the chin (Gn-Gn' and Me-Me'). Shallower mental sulcus and more obtuse chin angle existed in Group 4. Gender differences were noted in chin extension and throat angle. Positive correlations were found between MP/SN and various soft tissue measurements, including lip length and chin projection. No statistically significant differences were observed among the four groups in the upper face neither in linear nor in angular measurements.
Vertical facial divergence significantly influences soft tissue characteristics, particularly in the lower third of the face. Hyperdivergent individuals exhibit increased lip length and reduced chin thickness. Nose length and projection did not differ between the different divergent groups. These findings have clinical implications for orthodontic treatment planning, highlighting the need for individualized approaches based on vertical facial patterns.
颅面结构在横向、垂直和矢状三个维度上的排列决定了面部美学。虽然骨骼和牙齿因素会影响这些结果，但软组织特征，尤其是面部软组织（FST）厚度，越来越被认为很重要。然而，很少有研究探讨垂直面部差异对软组织变化的影响，特别是在面部的中下部。
本研究旨在评估成年患者垂直面部差异与上下面部三分之一的面部软组织特征之间的关联。
共纳入120名寻求正畸治疗的非生长型个体（60名男性，60名女性），平均年龄27.87岁（范围：18 - 56岁）。根据下颌平面相对于前颅底的倾斜度（MP/SN）将参与者分为四组：第1组：MP - SN≤27°，第2组：27°＜MP - SN≤32°，第3组：32°＜MP - SN＜37°，第4组：MP - SN≥37°。使用侧位头影测量X线片在特定解剖标志处测量水平面上的FST厚度，包括前额基部、鼻子、嘴唇和下巴。此外，评估唇长、下巴突出度和角度倾斜度。组间比较采用单因素方差分析，随后进行事后邦费罗尼检验。使用皮尔逊相关检验研究变量之间线性关系的强度。统计学显著性设定为p = 0.05。
各组之间在面部软组织特征方面观察到显著差异。与低角个体（第1组）相比，高角个体（第4组）的总面部高度（TFH）、下部面部高度（LFH）以及上下唇长度显著增加（p＜0.001）。第4组在下巴处（Gn - Gn'和Me - Me'）的软组织也更薄（p＜0.001）。第4组的颏沟更浅，下巴角度更钝。在下巴伸展和喉角方面存在性别差异。在MP/SN与各种软组织测量值之间发现了正相关，包括唇长和下巴突出度。在上面部，四组在长度和角度测量方面均未观察到统计学上的显著差异。
垂直面部差异显著影响软组织特征，尤其是在面部的下三分之一。高角个体表现出唇长增加和下巴厚度减小。不同差异组之间的鼻长和突出度没有差异。这些发现对正畸治疗计划具有临床意义，强调了基于垂直面部模式采取个性化方法的必要性。
