Facial Symmetry: An Illusion?

Abstract

Objective: To investigate the laterality of the normal asymmetry of the human face, examining differences in laterality in relation to sex, and skeletal classification. Materials and methods:A sample of 120 patients (60 males and 60 females; mean age, 15 years; range, 16-22 years) who had received orthodontic clinical examination at AME's Dental College and Hospital were selected. Selection was made in such a way that following malocclusions with equal sexual distribution was possible from the patient database. Patients selected were classified into skeletal Class I (25 males and 25 females), Class II (25 males and 25 females) and Class III (10 males and 10 females) based on ANB angle. The number was predecided to be the same and also was based on the number of patients with following malocclusions reported to the department. Differences in length between distances from the points at which ear rods were inserted to the facial midline and the perpendicular distance from the softtissue menton to the facial midline were measured on a frontofacial photograph. Subjects with a discrepancy of more than three standard deviations of the measurement error were categorized as having left-or right-sided laterality.Results: Of subjects with facial asymmetry, 74.1% had a wider right hemiface, and 51.6% of those with chin deviation had left-sided laterality. These tendencies were independent of sex or skeletal jaw relationships. Conclusion:These results suggest that laterality in the normal asymmetry of the face, which is consistently found in humans, is likely to be a hereditary rather than an acquired trait.

Evaluation and Correlation of Facial Asymmetry in Adults with Class I, Class II, and Class III Skeletal Relation

“…Sample size calculation was based on dFW (L-R) between different skeletal classes retrieved from previous research [14]. Using G power program version 3.1.9.4 to calculate size based on expected difference of 12%, using 2-tailed test, α error = 0.05 and power = 80.0%, the total calculated sample size will be 70 in each group by adding 5% to compensate possible drop out then total sample size will be 75 in each of the three groups (total 225).…”

“…Thus, in order to evaluate these varying levels of facial asymmetry and provide accurate assessment of its characteristics and severity, skeletal classi cations have been utilized by researchers, experts, and practitioners [5].For instance, various facial landmarks and planes can help identify such sections and proportionate points on someone's face. Similarly, symmetry is always considered the hallmark of beauty since it exhibits how each portion of the face share are equally proportionate to one another.…”