Effect of Facial Height on the Perception of Mandibular Asymmetry by Laypeople, Orthodontists and Oral and Maxillofacial Surgeons Publisher

Summary: Can facial height influence perceived mandibular asymmetry? Research suggests the long-faced may need treatment for smaller rotations. Surprising differences found in laypeople vs specialists. #Orthodontics #FacialAsymmetry

Donyavi H ; Kamali E ; Safari F ; Razmara F ; Geramy A ; Kharazifard M ; Arab S
Source: Clinical and Investigative Orthodontics Published:2026

Abstract

Purpose: This study evaluated how facial height affects perceptions of mandibular asymmetry in individuals with short and long faces, as viewed by three groups of raters. Materials and methods: Long-face and short-face models were selected based on the facial index. Symmetrical frontal-view photographs of the models were altered with mandibular rotations of 0–6 degrees. Seventy laypeople, 24 orthodontists, and 24 oral and maxillofacial surgeons rated the images for aesthetics using a 0–100 visual analogue scale (VAS) and assessed treatment needs. Data were analysed using ANOVA, LSD, Tukey’s HSD and Spearman correlation, with a significance set at p < 0.05. Results: The treatment need threshold for the long-face model was identified at 4, 4 and 5 degrees by orthodontists, surgeons and laypeople, respectively. In contrast, for the short-face model, it was 6 degrees according to orthodontists and surgeons; laypeople did not perceive a need for treatment even at 6 degrees. All groups detected 1-degree rotations in the long-face model. Still, in the short-face model, laypeople and orthodontists noticed 1-degree rotations, while surgeons did not show significant differences for 0-, 1- and 2-degree rotations but were better at detecting higher degrees. Conclusion: All raters identified a 1-degree detection threshold for mandibular rotation in the long-face model. In the short-face model, orthodontists and laypeople noted 1 degree, while surgeons noticed 3 degrees. The long-face model needed treatment for a lower degree of rotation based on all three rater groups. Specialists generally require lower degrees of asymmetry to determine treatment needs compared to laypeople. © 2026 Japanese Orthodontic Society. Published by Informa UK Limited, trading as Taylor & Francis Group.