Influence of Upper Incisor Inclination on Smiling Profile Aesthetics in Skeletal Class III

This study aimed to assess the influence of upper incisor inclinations on smiling profile aesthetics in skeletal Class III patients, considering the effects of skeletal simulations, the assessor’s expertise, and the assessor’s gender. A smiling profile photograph of a Thai female with normal skeletal, dental, and soft tissue features was digitally adjusted to represent 16 images with 4 skeletal simulations and 4 upper incisor inclinations. The number of assessors was 180, which included orthodontists, general dentists, and laypersons. They were asked to evaluate the smiling profile aesthetics of each image using a numerical rating scale. The aesthetic scores were analysed using a mixed between-within-subjects ANOVA (p < 0.05). The results showed that the interaction effect between orthodontic expertise and upper incisor inclinations was not observed in the skeletal Class III groups. Normal upper incisor inclination had the highest aesthetic score. Proclination of the upper incisors by 3° significantly decreases the aesthetic score, except in the skeletal Class III with prognathic mandible group. The assessor’s gender did not affect the aesthetics score of the smiling profile. In conclusion, upper incisor inclinations and skeletal simulations significantly influenced smiling profile aesthetics in the skeletal Class III simulations. The assessor’s expertise and gender did not affect the evaluations.