Chulalongkorn University, 34 Henri Dunant Road, Pathumwan, Bangkok, 10330, Thailand.
Prog Orthod. 2017 Dec;18(1):8. doi: 10.1186/s40510-017-0162-4. Epub 2017 Mar 20.
Age is a factor affecting smile esthetics. Three variables of smile esthetics associated with the maxillary anterior teeth and age-related changes have recently received considerable attention: (i) the incisal edge position of the maxillary central incisors, (ii) the maxillary gingival display, and (iii) the presence of a black triangle between the maxillary central incisors. The aim of this study was to evaluate the influence of age on smile esthetic perception based on these three variables in a group of Thai laypeople.
The smiles were constructed from a photograph of a female smile. Smile photographs were altered in various increments using three variables: the incisal edge position of the maxillary incisors, gingival display, and a black triangle between the maxillary central incisors. The photographs were shown to a group of 240 Thai laypeople. The subjects were divided into two groups: a younger group, 15-29 years old (n = 120) and an older group, 36-52 years old (n = 120). Each subject was asked to score the attractiveness of each smile separately using a visual analog scale.
Smile attractiveness scores concerning the incisal edge positions of the maxillary central incisors were similar between the two groups. However, upper lip coverage was rated as unattractive by the younger group. A gingival display of 0 and 2 mm was rated as most attractive by the younger group. Upper lip coverage and gingival display of 0 and 2 mm were considered attractive by the older group. Excessive gingival display (6 mm) was scored as unattractive by both groups. A black triangle ranging from 1 to 2.5 mm between the maxillary central incisors was scored differently between the two groups. The older group was more tolerant of the black triangle size.
Age impacts smile perception based on maxillary gingival display and the presence of a black triangle between the maxillary central incisors, but not of the incisal edge position of the maxillary central incisors. Due to the variation in esthetic perception of each individual, participation between orthodontists and patients for decision-making and treatment planning is a crucial process to provide successful results.
年龄是影响微笑美观的一个因素。最近，与上颌前牙和年龄相关变化相关的三个微笑美观变量受到了相当大的关注：（i）上颌中切牙切缘位置，（ii）上颌牙龈显露，以及（iii）上颌中切牙之间的黑三角。本研究旨在评估基于这三个变量，年龄对泰国非专业人士对微笑美观感知的影响。
微笑是通过对女性微笑的照片进行构建而成。使用三个变量（上颌切牙的切缘位置、牙龈显露和上颌中切牙之间的黑三角）对照片进行不同程度的修改。将照片展示给一组 240 名泰国非专业人士。受试者分为两组：15-29 岁的年轻组（n=120）和 36-52 岁的较年长年组（n=120）。每位受试者都被要求使用视觉模拟量表分别对每个微笑的吸引力进行评分。
上颌中切牙切缘位置的微笑吸引力评分在两组之间相似。然而，年轻组认为上唇覆盖度不吸引人。0 和 2mm 的牙龈显露被年轻组评为最吸引人。0 和 2mm 的上唇覆盖度和牙龈显露被年长组认为是有吸引力的。两组都认为牙龈显露过多（6mm）不吸引人。上颌中切牙之间 1 至 2.5mm 的黑三角大小评分在两组之间有所不同。年长组对黑三角的大小更为宽容。
年龄会影响基于上颌牙龈显露和上颌中切牙之间黑三角大小的微笑感知，但不会影响上颌中切牙切缘位置。由于每个人对美观的感知存在差异，因此正畸医生和患者之间的参与对于决策和治疗计划至关重要，这是提供成功治疗效果的关键过程。
