Effects of laterality on esthetic preferences of orthodontists, maxillofacial surgeons, and laypeople regarding the lip position and facial convexity: a psychometric clinical trial

Effects of facial forms and midline deviations and rolls on female facial beauty according to laypeople, orthodontists, and prosthodontists or restorative dentists

No study has examined the simultaneous effect of facial forms, midline deviations and midline angulations on facial beauty. Therefore, this comprehensive study aimed to evaluate these and many other hypotheses. This psychometric study was performed on 15,042 observations. A female frontal photograph was edited to 45 perceptometric images with controlled anatomical alteration: 3 facial forms (euryprosopic [brachyfacial], mesoprosopic [mesofacial], leptoprosopic [dolichofacial]), each having either 9 bidirectional midline deviations (0, 1, 2, 3, and 4 mm deviated to the left and right) or 7 bidirectional midline angular deviations (0°, 5°, 10°, and 15° deviated to the left and right). One of the photographs were repeated. These 46 images were esthetically judged by 327 participants (243 laypeople, 49 orthodontists, and 35 'prosthodontists or restorative dentists'). Hierarchical mixed-model multiple linear regressions and post hoc tests were adopted to evaluate the simultaneous impacts of the photomodel's facial forms, midline deviations to the right or left, and midline rolls to the right or left plus sex, age, experience, and dental specialty of the referees on their perception of facial beauty as well as the tolerable zones of midline alterations. These were also done separately for each specialty group, and also for each facial face. Ideal combinations of anatomic features were determined using repeated-measures ANOVAs. Differences between esthetic preferences of different groups in terms of each image were assessed using one-way ANOVAs and t-tests (α = 0.05, α = 0.008, α = 0.001). All 5 anatomical features significantly and independently influenced perception of facial beauty. The tolerance threshold for midline deviations was 1 mm deviations to the right and left sides. For midline rolls, the only tolerable form was the no-roll ('on') midline; the judges preferred right-oriented defects over left-sided ones. The most beautiful facial form was mesoprosopic, followed by leptoprosopic. Men perceived the female face slightly more attractive than did women. The viewers' specialty (or lack of it), their age, or their experience did not affect their esthetic preferences. Predictors of esthetic preferences were all 5 anatomical features plus views' sex, but not their dental specialty, age, or experience. Zones of acceptability and also the ideal range of anatomical features were determined.

Attractive combinations of female gingival displays, buccal corridor sizes, and facial heights according to orthodontists, dentists, and laypeople of different ages and sexes: a psychometric study

INTRODUCTION

Esthetics plays a crucial role in orthodontics and many other dental and medical fields. To date, no study has assessed the combined effects of the 3 facial features 'facial height, gingival display (GD), and buccal corridor size (BC)' on facial/smile beauty. Therefore, this study was conducted for the first time.

METHODS

In this psychometric diagnostic study, beauty of 27 randomized perceptometric images of a female model with variations in facial heights (short, normal, long), gingival displays (0, 2, 4, 6 mm), and buccal corridor sizes (2%, 10%, 15%, 20%, 25%) were evaluated by 108 judges (36 orthodontists, 36 dentists, 36 laypeople) using a 5-scale Likert scale (1 to 5). Combined effects of facial heights, GDs, BCs, judges' sexes, ages, and jobs, and their 2-way interactions were tested using a mixed-model multiple linear regression and a Bonferroni test. Zones of ideal features were determined for all judges and also for each group using repeated-measures ANOVAs and the Bonferroni test (α=0.05).

RESULTS

Judges' sex but not their age or expertise might affect their perception of female beauty: men gave higher scores. The normal face was perceived as more beautiful than the long face (the short face being the least attractive). Zero GD was the most attractive followed by 4 mm; 6 mm was the least appealing. BCs of 15% followed by 10% were the most attractive ones, while 25% BC was the worst. The zone of ideal anatomy was: long face + 0mm GD + 15% BC; normal face + 2mm GD + 15% BC; long face + 2mm GD + 15% BC; normal face + 0mm GD + 15% BC.

CONCLUSIONS

Normal faces, zero GDs, and 15% BCs may be the most appealing. Facial heights affect the perception of beauty towards GDs but not BCs.

Influence of lip position on esthetics perception with respect to profile divergence using silhouette images

BACKGROUND

The aim of the study was to determine the facial divergence and lip position combinations that are most and least preferred, and to investigate whether age or gender has an impact on these preferences.

METHODS

The current investigation was carried out on a sample of 1077 individuals who were not experts in the field (253 men and 824 females). The research employed black silhouette photographs of profiles featuring different lip locations and profile divergences. The recruitment of participants was conducted in order to assess the attractiveness of the profiles, employing a Likert scale. The various positions of the lips and variations in facial profiles were thoroughly categorized. Results were analyzed using the Chi-square test.

RESULTS

The findings of the research demonstrated that aesthetic perceptions displayed diversity when considering different lip locations and profile divergences. It was shown that neutral lip positions were predominantly favored, accounting for approximately 40.2% of the total frequencies in the anterior diverging group. It is noteworthy to highlight the aesthetically pleasing features exhibited by those with the most prominent lip position, occurring at a frequency of 10.9% in straight-diverging group. In the posterior divergent group, the most protruded lip position, showed very attractive aesthetics with frequency (7.1%). Gender, age, region, and level of education had significant influence on aesthetic perception.

CONCLUSIONS

The variety of aesthetic preferences is influenced by the location of the lips and the divergence of the facial profile, resulting in different outcomes within the categories of anterior, straight, and posterior divergence. Clinicians are advised to customize the treatment regimen in order to correspond with the unique desires and preferences of the patient.

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

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 (α = 0.05, α = 0.0056, α = 0.0021, and β = 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.

Influence of Lip Projection and Chin Position on Facial Profile Preferences Among Various Layers of Polish Population. Part 1

Purpose

This study aims to evaluate how the extent of altering lip projection in women and chin position in men influences the 22-year-old Caucasian's facial profile attractiveness, in relation to respondents' sex, age and place of residence.

Materials and Methods

One female and one male orthognathic (SNA angle = 79-85°, Z angle = 75-78°) face profiles, with lips correctly positioned in relation to the E-line were photographed and digitally modified. This processing resulted in 30 photographs varying as for 1. the SNA angle determining orthognathic, prognathic (SNA angle >85°), or retrognathic (SNA angle <79°) profile and 2. lip projection/chin position: normal or protruded/retruded by 1 or 2 mm. The photographs were always shown in the same order to 418 respondents (306 women and 112 men) aged between 15 and 73 years, who provided their place of residence. The 11-point visual analogue scale (VAS) was used for the assessment of the facial profile attractiveness.

Results

All respondents found the prognathic profile with correct lip position in woman and correct chin position in man most attractive. Each major deviation from the norm resulted in a decrease in the scores awarded. Men ranked rethrognathic profiles significantly (p < 0.05) higher than women. The respondents under and over 25 years also differred (p < 0.05) in their evaluation: the older viewers were more critical regarding all female profiles with an exception of the retrognathic profile with 2 mm lips protrusion. The respondents' place of residence did not affect the rating.

Conclusion

1 mm modification of lip projection and chin position significantly alter ranking the face profile attractiveness, thus any aesthetic medicine applied in this area requires extreme caution. Moreover, visualizing the results should be mandatory, especially in women older than 25 years of age, who are the most critical evaluators.

The Diversity Bonus in Oral and Maxillofacial Surgery

The diversity bonus theorem developed by Scott Page postulates that in specific environments, diversity is an absolute necessity to creating the most successful team. The theorem dispels the myth that institutions must choose between diversity and excellence. Within oral and maxillofacial surgery, this bonus is captured through expanded access to care, more equitable and relevant research, and attracting the best and brightest to the specialty. To capture the bonus, oral and maxillofacial surgery must invest in policy changes to admissions and hiring practices, and offer training in communication, cultural competency, and implicit bias.

Evaluation of Perceptions of Smile Esthetics by Dental Students

Background/Aim: The aim of this study was to investigate in the esthetic perceptions of 2nd grade dental students before and after training.

Material and Methods: A total of 16 photographs which contain golden ratio, buccal corridor, midline deviation, incisal embrasure, lip line, midline diastema, dark triangles and smile arc were shown to 78 dental students (33 male, 45 female). Immediately after the training about the smile esthetics, the same photos were shown again. The effect of gender on esthetic perception was also examined, in addition to assessing the effects of education on esthetic perception. Pearson Chi-square, Fisher’s Exact test and McNemar test were used in the analysis of the results.

Results: According to the results of the analysis, it was found that the answers of the smile arc before and after the education were statistically significant (p< 0.05). Accordingly, the rate of correct answers of women is statistically higher than that of men. A statistically significant difference was found between the responses to the gingival appearance in the smile before and after the education (p< 0.05).

Conclusions: Based on the limited results of this study, professional dental education may affect the esthetic evaluation of smile. There were differences in the esthetic perception of women and men.

Effects of different surgical techniques and displacement distances on the soft tissue profile via orthodontic-orthognathic treatment of class II and class III malocclusions

Background

Orthognathic surgery can be carried out using isolated mandibular or maxillary movement and bimaxillary procedures. In cases of moderate skeletal malocclusion, camouflage treatment by premolar extraction is another treatment option. All these surgical procedures can have a different impact on the soft tissue profile.

Methods

The changes in the soft tissue profile of 187 patients (Class II: 53, Class III: 134) were investigated. The treatment approaches were differentiated as follows: Class II: mandible advancement (MnA), bimaxillary surgery (MxS/MnA), upper extraction (UpEX), or Class III: maxillary advancement (MxA), mandible setback (MnS), bimaxillary surgery (MxA/MnS), and lower extraction (LowEX) as well as the extent of skeletal deviation (moderate Wits appraisal: − 7 mm to 7 mm, pronounced: Wits <− 7 mm, > 7 mm, respectively). This resulted in five groups for Class II treatment and seven groups for Class III treatment.

Results

In the Class II patients, a statistically significant difference (p ≤ 0.05) between UpEX and moderate MnA was found for facial profile (N′-Prn-Pog’), soft tissue profile (N′-Sn-Pog’), and mentolabial angle (Pog’-B′-Li). In the Class III patients, a statistically significant differences (p ≤ 0.05) occurred between LowEX and moderate MxA for facial profile (N′-Prn-Pog’), soft tissue profile (N′-Sn-Pog’), upper and lower lip distacne to esthetic line (Ls/Li-E-line), and lower lip length (Sto-Gn’). Only isolated significant differences (p < 0.05) were recognized between the moderate surgical Class II and III treatments as well between the pronounced Class III surgeries. No statistical differences were noticed between moderate and pronounced orthognathic surgery.

Conclusions

When surgery is required, the influence of orthognathic surgical techniques on the profile seems to be less significant. However, it must be carefully considered if orthognathic or camouflage treatment should be done in moderate malocclusions as a moderate mandibular advancement in Class II therapy will straighten the soft tissue profile much more by increasing the facial and soft tissue profile angle and reducing the mentolabial angle than camouflage treatment. In contrast, moderate maxillary advancement in Class III therapy led to a significantly more convex facial and soft tissue profile by decreasing distances of the lips to the E-Line as well as the lower lip length.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13005-021-00264-4.