Human Commercial Models' Eye Colour Shows Negative Frequency-Dependent Selection

Perceived Effects of Orthognathic Surgery versus Orthodontic Camouflage Treatment of Convex Facial Profile Patients

Increased facial profile convexity has a common occurrence in the population and is a primary reason for seeking orthodontic treatment. The present study aimed to compare the perceived changes in facial profile appearance between patients treated with combined orthognathic/orthodontic treatment versus only orthodontic camouflage treatment. For this reason, 18 pairs of before- and after-treatment facial profile photos per treatment group (n = 36 patients) were presented to four types of assessors (surgeons, orthodontists, patients, laypeople). Ratings were recorded on 100 mm visual analogue scales depicted in previously validated questionnaires. All rater groups identified minor positive changes in the facial profile appearance after exclusively orthodontic treatment, in contrast to substantial positive changes (14% to 18%) following combined orthodontic and orthognathic surgery. The differences between the two treatment approaches were slightly larger in the lower face and the chin than in the lips. The combined orthodontic and orthognathic surgery interventions were efficient in improving the facial appearance of patients with convex profile, whereas orthodontic treatment alone was not. Given the significant influence of facial aesthetics on various life aspects and its pivotal role in treatment demand and patient satisfaction, healthcare providers should take these findings into account when consulting adult patients with a convex facial profile.

The effect of orthodontic treatment on smile attractiveness: a systematic review

BACKGROUND

Smile attractiveness is a primary factor for patients to seek orthodontic treatment, however, there is yet no systematic evaluation of this topic in the literature.

OBJECTIVES

To assess the current evidence on the effect of orthodontic treatment on smile attractiveness.

SEARCH METHODS

Seven electronic databases (MEDLINE, Cochrane Library, Virtual Health Library, SCOPUS, Web of Science, Google Scholar and Embase) were searched on 14 September 2022.

SELECTION CRITERIA

Studies evaluating smile attractiveness before and after orthodontic treatment or only after completion of orthodontic treatment.

DATA COLLECTION AND ANALYSIS

Extracted data included study design and setting, sample size and demographics, malocclusion type, treatment modality and method for outcome assessment. Risk of bias was assessed with the ROBINS-I tool for non-randomised studies. Random-effects meta-analyses of mean differences and their 95% confidence intervals (CIs) were planned a priori.

METHODS

After elimination of duplicate studies, data extraction and risk of bias assessment according to the Cochrane guidelines, an evaluation of the overall evidence was performed. The included studies were evaluated based on the characteristics of their study and control groups and based on their main research question. Also, all outcome measures were standardized into a common assessment scale (0-100), in order to obtain more easily interpretable results.

RESULTS

Ten studies were included in this review, nine of which were assessed as being at serious risk of bias and one at moderate risk of bias. The large heterogeneity between the included studies did not allow for a meta-analysis. Orthodontic treatment has a moderately positive effect on smile attractiveness. When compared to no treatment, orthodontic treatment with premolar extractions improves smile attractiveness by 22%. Also, surgical correction of Class III cases increases smile attractiveness by 7.5% more than camouflage treatment. No other significant differences were shown between different types of treatment.

CONCLUSION

Based on the available data, orthodontic treatment seems to moderately improve the attractiveness of the smile. There is significant bias in the current literature assessing the effect of orthodontics on smile attractiveness; therefore, the results cannot be accepted with certainty.

Consistency of Eye Coloration Across Different Relationship Partners

Studies have indicated that people are attracted to partners who resemble themselves or their parents, in terms of physical traits including eye color. We might anticipate this inclination to be relatively stable, giving rise to a sequential selection of similar partners who then represent an individual's "type". We tested this idea by examining whether people's sequential partners resembled each other at the level of eye color. We gathered details of the eye colors of the partners of participants (N = 579) across their adult romantic history (N = 3250 relationships), in three samples, comprising two samples which made use of self-reports from predominantly UK-based participants, and one which made use of publicly available information about celebrity relationship histories. Recorded partner eye colors comprised black (N = 39 partners), dark brown (N = 884), light brown (N = 393), hazel (N = 224), blue (N = 936), blue green (N = 245), grey (N = 34), and green (N = 229). We calculated the proportion of identical eye colors within each participant's relationship history, and compared that to 100,000 random permutations of our dataset, using t-tests to investigate if the eye color of partners across an individual's relationship history was biased relative to chance (i.e., if there was greater consistency, represented by higher calculated proportions of identical eye colors, in the original dataset than in the permutations). To account for possible eye color reporting errors and ethnic group matching, we ran the analyses restricted to White participants and to high-confidence eye color data; we then ran the analyses again in relation to the complete dataset. We found some limited evidence for some consistency of eye color across people's relationship histories in some of the samples only when using the complete dataset. We discuss the issues of small effect sizes, partner-report bias, and ethnic group matching in investigating partner consistency across time.

Facial shape affects self-perceived facial attractiveness

Facial appearance expresses numerous cues about physical qualities as well as psychosocial and personality traits. Attractive faces are recognized clearly when seen and are often viewed advantageously in professional, social and romantic relationships. On the other hand, self-perceived attractiveness is not well understood and has been mainly attributed to psychological and cognitive factors. Here we use 3-dimensional facial surface data of a large young adult population (n = 601) to thoroughly assess the effect of facial shape on self-perceived facial attractiveness. Our results show that facial shape had a measurable effect on self-perception of facial attractiveness in both sexes. In females, self-perceived facial attractiveness was linked to decreased facial width, fuller anterior part of the lower facial third and more pronounced middle forehead and root of the nose. Males favored a well-defined chin, flatter cheeks and zygomas, and more pronounced eyebrow ridges, nose and middle forehead. The findings of this study support the notion that self-perceived facial attractiveness is not only motivated by psychological traits, but objectively measured phenotypic traits also contribute significantly. The role of social stereotypes for facial attractiveness in modern society is also inferred and discussed.

Genetic and phenotypic variability of iris color in Buenos Aires population

The aim of this work was to describe the phenotypic and genotypic variability related to iris color for the population of Buenos Aires province (Argentina), and to assess the usefulness of current methods of analysis for this country. We studied five Single Nucleotide Polymorphisms (SNPs) included in the IrisPlex kit, in 118 individuals, and we quantified eye color with Digital Iris Analysis Tool. The markers fit Hardy-Weinberg equilibrium for the whole sample, but not for rs12913832 within the group of brown eyes (LR=8.429; p=0.004). We found a remarkable association of HERC2 rs12913832 GG with blue color (p < 0.01) but the other markers did not show any association with iris color. The results for the Buenos Aires population differ from those of other populations of the world for these polymorphisms (p < 0,01). The differences we found might respond to the admixed ethnic composition of Argentina; therefore, methods of analysis used in European populations should be carefully applied when studying the population of Argentina. These findings reaffirm the importance of this investigation in the Argentinian population for people identification based on iris color.