Assessing soft-tissue characteristics of facial asymmetry with photographs

Introduction Precise diagnosis and treatment of facial asymmetry are important in orthodontics. The aims of this study were to determine the soft-tissue characteristics of patients perceived to have severe asymmetry requiring treatment and the soft-tissue factors affecting the subjective assessment of facial asymmetry. Methods In the first part of this study, 5 observers examined 1000 photographs of patients receiving orthodontic treatment and selected 100 for further assessment. These photographs showed 50 patients who were considered to have little or moderate asymmetry and 50 who were considered to have severe asymmetry. A pilot study was performed to select the reference photographs representing the most symmetric (score of 0) and the most asymmetric (score of 100). A panel of 9 orthodontists then rated the facial asymmetry of the 100 patients on a 100-mm visual analog scale. The scale was divided into 3 equal regions. Region 1 included patients with the least facial asymmetry; according to the orthodontists, these patients did not require treatment. Region 2 included patients with moderate facial asymmetry who did not require treatment. Region 3 included patients with the most facial asymmetry who did require treatment. Results One-way analysis of variance showed that lip canting, chin deviation, body inclination difference, and gonial angle difference had significant differences between the groups. Chin deviation and gonial angle difference were significant factors affecting the assessment of facial asymmetry, according to stepwise linear regression analysis. Conclusions These results will help in the diagnosis and treatment planning for patients with asymmetry.