Department of Orthodontics, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Dentofacial Deformities Research Center, Research Institute of Dental Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Students' Research Committee, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Am J Orthod Dentofacial Orthop. 2023 Dec;164(6):766-773. doi: 10.1016/j.ajodo.2023.04.022. Epub 2023 Aug 9.
This study aimed to compare the characteristics of pleasant and unpleasant smiles from the perception of laypeople.
Two-hundred posed smile photographs were obtained from adult participants with no anomaly, restoration, or severe crowding and spacing in anterior teeth. Photographs were shown to 26 judges to give each photograph a score for attractiveness. Upper and lower quartiles for the most and least rated smiles were determined, and variables including gingival display, smile arc, midline deviation, buccal corridor, smile width, tooth rotation or malposition, diastema, upper and lower vermilion show, and tooth form were measured. Independent-sample t test and Pearson chi-square analysis were used to determine the differences between the pleasant and unpleasant groups for quantitative and qualitative variables, respectively. The linear regression model revealed variables with the most significant impact on the mean score.
All quantitative and qualitative variables except tooth form significantly differed between pleasant and unpleasant smile groups (P <0.05). The consonant smile arc was associated with an increase of 12.59% in mean scores compared with the inconsonant smile arc. Each tooth reported with malposition was correlated with a decrease of 9.37% in the scores. In the same way, each 1-mm increase in midline diastema and occlusal cant coincided with a drop of 8.73% and 3.59% in scores, respectively.
The results of this study suggested that smile arc, tooth malposition, midline diastema, and occlusal plane canting had the most impact on smile esthetics and should be given priority by orthodontists in the treatment plan of choice.
本研究旨在比较普通人对愉悦和不愉悦微笑特征的感知。
从无牙异常、修复体或前牙严重拥挤和间隙的成人参与者中获得 200 张摆拍微笑照片。将照片展示给 26 名评委，让他们对每张照片的吸引力进行评分。确定最受好评和最不受好评的微笑的上下四分位数，并测量包括牙龈显露、微笑弧、中线偏斜、颊廊、微笑宽度、牙齿旋转或错位、间隙、上、下唇红显露和牙齿形态等变量。使用独立样本 t 检验和 Pearson 卡方分析分别确定定量和定性变量在愉悦和不愉悦组之间的差异。线性回归模型揭示了对平均得分影响最大的变量。
除牙齿形态外，所有定量和定性变量在愉悦和不愉悦微笑组之间均有显著差异（P<0.05）。协调的微笑弧与平均得分增加 12.59%相关，而不协调的微笑弧则相反。每颗错位的牙齿与得分降低 9.37%相关。同样地，中线间隙每增加 1mm 和牙合平面倾斜各对应得分降低 8.73%和 3.59%。
本研究结果表明，微笑弧、牙齿错位、中线间隙和牙合平面倾斜对微笑美观的影响最大，正畸医生在制定治疗方案时应优先考虑这些因素。
