The study of individuals’ preferences for smile aesthetics in frontal, oblique, and lateral view images

Smile aesthetics play a central role in facial attractiveness and often influence patients' expectations in orthodontic treatment. The study aimed to determine individuals’ preferences for smile aesthetics in frontal, oblique, and lateral view images and to compare the preferences of general population (laypeople) and dentists. There were 19 variables of smile photographs were designed respectively in frontal view (8), oblique view (4), and lateral view (7). Each variable was created based on previous studies and standard deviation values using Adobe Photoshop (version CS6) to produce five images, resulting in 95 images in total. Taiwanese laypeople, general dentists, and orthodontists completed an online questionnaire evaluating these images. Statistical analysis included Pearson chi-square tests and logistic regression. This study included 773 participants, comprising 412 women and 361 men. The participants' mean age was 20–40 years. The sample comprised 351 laypeople, 188 general dentists, and 63 orthodontists. Their preferences for the smile aesthetics were strongly influenced by identity, age, and gender, with identity having the greatest influence. The chi-square test revealed differences in preferences between gender and identity subgroups. Preferences for arc ratio, posterior tooth visibility, and maxillary and mandibular tooth exposure varied among the frontal, oblique, and lateral view images. A customized smile chart was designed based on the participants’ preferences for smile aesthetics to provide a reference for orthodontic diagnosis and treatment planning. Identity, gender, and age strongly influenced smile perceptions, with identity having the strongest impact. Accordingly, we propose that the most beautiful smile is one that achieves the greatest consensus in terms of individuals’ preferences for smile aesthetics while maintaining normal physiological function and form.