Cephalometric determinants of facial attractiveness: A quadratic correlation study

Establishing H Angle Hard Tissue and H Angle Soft Tissue Norms in Skeletal Class I Malay Adult Females and the Correlation between the H Angles and Visual Perception of Laypersons

OBJECTIVES

 This study aimed to establish the cephalometric norms of H angle soft tissue and H angle hard tissue of Malaysian Malay adult females, and to evaluate the correlation between H angles and visual perception in skeletal Class I Malay adult females.

MATERIALS AND METHODS

 Eighty-five lateral cephalograms of skeletal Class I (mean ANB value = 3.15 ± 0.77) Malaysian Malay female patients aged 20 to 40 years (mean age = 28.6 ± 5.86 degrees) taken from October 2017 to December 2021 were measured for H angle soft tissue and H angle hard tissue. Twenty silhouettes were then converted from cephalometric films and were rated according to facial convexity/concavity by 20 laypersons, with re-evaluation after 2 weeks for intra- and interexaminer reliabilities.

RESULTS

 The means of the H angle soft tissue and H angle hard tissue were 15.75 ± 4.16 degrees and 11.64 ± 4.71 degrees, respectively. The intraexaminer reliability test for visual perception ranged from -0.89 to 0.99 indicating poor to excellent reliability, whereas the interexaminer reliability test was 0.82 indicating good reliability. A highly statistically significant association between the H angle soft tissue and H angle hard tissue (r = 0.938; p < 0.01) was found. There was no correlation between H angles and visual perception.

CONCLUSION

 The cephalometric norms of H angle hard tissue and H angle soft tissue in the Malaysian Malay female population were established: 11.64 degrees (±4.71 degrees) and 15.75 degrees (±4.16 degrees), respectively. There was a strong correlation between H angle soft tissue and H angle hard tissue among skeletal Class I Malay adult females. There was no correlation between H angles and the visual perception of laypersons.

Impact of orthodontic-induced facial morphology changes on aesthetic evaluation: a retrospective study

BACKGROUND

The profound influence of orthodontic treatments on facial aesthetics has been a topic of increasing interest. This study delves into the intricate interplay between orthodontic treatments, facial feature alterations, and aesthetic perceptions.

METHODS

A total of 73 patients who had undergone orthodontic treatment were included in this study. Facial photographs were taken before and after treatment. Ten orthodontists provided facial aesthetic ratings (FAR) for each patient's frontal, profile, and overall views. 48 facial landmarks were manually placed by the orthodontists and normalized using Generalized Procrustes analysis (GPA). Two types of phenotypes were derived from facial landmarks. Global facial phenotypes were then extracted using principal component analysis (PCA). Additionally, 37 clinical features related to aesthetics and orthodontics were extracted. The association between facial features and changes in FAR after orthodontic treatment was determined using these two types of phenotypes.

RESULTS

The FAR exhibited a high correlation among orthodontic experts, particularly in the profile view. The FAR increased after orthodontic treatment, especially in profile views. Extraction of premolars and orthognathic surgery were found to result in higher FAR change. For global facial phenotypes, the most noticeable changes in the frontal and profile views associated with FAR occurred in the lip area, characterized by inward retraction of the lips and slight chin protrusion in the profile view, as well as a decrease in lip height in the frontal view. The changes observed in the profile view were statistically more significant than those in the frontal view. These facial changes were consistent with the changes from orthodontic treatment. For clinical features, two profile features, namely pg.sm.hori and pg.n.ls, were found to be associated with FAR following orthodontic treatment. The highest FAR scores were achieved when pg.sm.hori was at 80° and pg.n.ls was at 8°. On the other hand, frontal clinical features had a subtle effect on FAR during orthodontic treatment.

CONCLUSIONS

This study demonstrated that orthodontic treatment improves facial aesthetics, particularly at lip aera in the profile view. Profile clinical features, such as pg.sm.hori and pg.n.ls, are essential in orthodontic treatment which could increase facial aesthetics.