Perceptions of Buccal Corridor and Smile Line by Laypersons and Professionals

Abstract

Background: Perceptions of smile esthetics often differ between dental professionals and laypersons, particularly regarding the buccal corridor and smile line. These differences may affect treatment planning and patient satisfaction. Objectives: This study aimed to compare the perceptions of dental professionals and laypersons regarding the buccal corridor and smile line across different vertical facial dimensions. Methods: This descriptive-analytical cross-sectional study was conducted in 2022 at the Faculty of Dentistry, Babol University of Medical Sciences, Babol, Iran. Seventy-two participants, including 36 dental professionals and 36 laypersons, evaluated standardized photographs of 3 male patients with short, normal, and long facial heights, classified according to the facial index. The patient inclusion criteria were similar age, completed orthodontic treatment, full dentition, and the absence of anterior tooth rotation. The exclusion criteria were a history of orthognathic or plastic surgery, cleft lip and palate, facial asymmetry, or syndromic conditions. Laypersons had previous dental treatment experience but no orthodontic treatment or professional esthetic training, whereas professionals had specialized expertise in esthetic dentistry. Buccal corridor width and smile arc were digitally modified, and attractiveness was rated using a Visual Analogue Scale (VAS). Data were analyzed using the independent-samples t-test, one-way analysis of variance, the Mann-Whitney U test, and the chi-square test, with the significance level set at 0.05. Results: Professionals demonstrated greater sensitivity than laypersons to differences in buccal corridor width and smile arc, particularly in long-faced patients. In this subgroup, professionals assigned significantly lower attractiveness scores than laypersons for both full-face images (4.41 ± 1.78 vs 5.96 ± 1.62; P < 0.001) and close-up images (4.68 ± 1.83 vs 5.94 ± 1.33; P = 0.001). Laypersons preferred flat smile arcs, whereas professionals favored consonant smile arcs; significant intergroup differences were observed mainly in long-faced subjects (P = 0.049 to P < 0.001). Conclusions: Dental professionals and laypersons differed significantly in their perceptions of the buccal corridor and smile line across vertical facial dimensions. Potential biases related to sample selection and image characteristics were acknowledged; therefore, the findings should be interpreted with caution. These results highlight the importance of integrating clinical expertise with patients’ esthetic perceptions in orthodontic treatment planning.