Psychometric and Perceptometric Comparisons of the Perspectives of Orthodontists, Oral and Maxillofacial Surgeons, and Laypeople of Different Ages and Sexes towards Beauty of Female Jaw Angles (Intergonial Widths and Gonial Heights) on Frontal and Three-Quarter Views

Abstract

Objectives. The jaw angle plays an important role in facial beauty. Therefore, this study is aimed at comparatively determining the range of most attractive female intergonial widths and gonial heights on Perceptometric frontal-view and three-quarter-view images, from the perspective of orthodontists, oral maxillofacial (OMF) surgeons, and laypeople of different ages and sexes. Methods. This prospective multivariate Perceptometric study was performed on 4191 esthetic scores given by 127 individuals to 33 Perceptometric face images. Frontal view and three-quarter-view photographs of a normal young woman were modified by image editing software to create two Perceptometric sets, one for the 24 gradual changes of intergonial width on the frontal view, and the other for the 9 vertical changes of the jaw angle on the three-quarter view. An online questionnaire was designed including 24 frontal and 9 oblique view photographs. The questionnaires’ internal consistencies were almost perfect. Enrolled were 127 raters, including 33 orthodontists, 32 OMF surgeons, and 62 laypeople. The esthetics of different images were compared across different professions, across different ages, and between the sexes using 2-way MANCOVA, ANCOVA, and Bonferroni; the zones of esthetic jaw angles and also the sensitivity of judges to Perceptometric anatomical changes were assessed using 2-way RM-ANCOVA and Bonferroni ( $\alpha =0.05$ , $\alpha =0.0056$ , $\alpha =0.0021$ , and $\beta =0.05$ ). Results. Orthodontists and surgeons gave the highest attractiveness scores to intergonial: interzygomatic ratio of 72.53%, while the best ratio was 74.45% for the laypeople. The range of beautiful intergonial is as follows: interzygomatic ratio was 72.53% to 86.03%. OMF surgeons and orthodontists gave the highest score to a gonial height of 4.5 mm above the mouth corner, while the laypeople gave the highest score to the gonial height of 4.5 mm below the mouth corner. The range of beautiful gonial height was from 4.5 mm above the mouth corner to 9 mm below the mouth corner. The education of observers may affect their perception of beauty; orthodontists tended differ from laypeople, overall and also specifically in the case of the highly attractive frontal images concerning the intergonial width changes. However, no such differences were detected between surgeons with orthodontists or laypeople. Although age did not affect the overall esthetic scores, it did affect the sensitivity of the judges to the anatomic changes. So did expertise, i.e., the expertise of judges affected their sensitivity to anatomical changes; orthodontists showed steeper slopes of esthetic preference alterations to anatomical changes, while laypeople had the gentlest slope of preference changes. Judges’ sex did not affect either their overall esthetic preferences or their sensitivity to anatomic changes. Conclusion. Narrower female jaw angles and jaw angles that are vertically close to the level of the mouth corner may be unanimously more desirable. Thus, treatments aiming at widening the jaw angle of a woman or lowering it should be discouraged, at least in Persians. Orthodontists, but not surgeons, are more sensitive than laypeople to anatomic changes of the jaw angle. The judges’ age can affect this perceptive sensitivity, but their sex cannot.