Smile dynamics: A comparative study of Fijians and NZ Europeans.

BACKGROUND: The Fijian 'Bula Smile' is often described as the world's friendliest; however, its description remains anecdotal. OBJECTIVE: This study aimed to describe and compare the dynamics of Fijians' smiles with those of New Zealand Europeans. METHODS: An observational study was conducted on two ethnic groups, Fijians (FJ; N = 23) and New Zealand Europeans (NZ; N = 23), age- and gender-matched. All participants were asked to watch amusing videos, and their reactions were video recorded. The videos were analysed by software to assess the frequency, duration, intensity and genuineness of smiling episodes. Based on the Facial Action Coding System, Action Unit 6 (AU6-cheek raiser), Action Unit 12 (AU12-lip corner puller) and Action Unit 25 (AU25-lips apart) were assessed. Data were analysed by generalised linear models after adjusting for personality traits. RESULTS: Fijians smiled longer than New Zealand Europeans (+19.9%; p = .027). Mean intensity of AU6 (+1.0; 95%CIs = 0.6-1.5; p < .001), AU12 (+0.5; 95%CIs = 0.1-0.9; p = .008) and AU25 (+22.3%; 95%CIs = 7.3%-37.3%; p = .005) were significantly higher in FJ group than the NZ group. CONCLUSION: Smiling features of Fijians and New Zealanders showed objective differences, the most distinctive being a higher activation of the Duchenne's marker (AU6) in the Fijian group, which is regarded as a sign of smile genuineness.

Malocclusion severity and smile features: Is there an association?

INTRODUCTION: This observational study investigated the relationship between malocclusion and smiling. METHODS: Adolescents and young adults (n = 72; aged 16-25 years) were identified according to their Dental Aesthetic Index (DAI) and allocated to 3 groups: (1) malocclusion group (n = 24; DAI ≥31), (2) retention group (n = 24; pretreatment DAI ≥31) with a prior malocclusion that had been corrected by orthodontic treatment, (3) control group with no-to-minor malocclusion (n = 24; DAI ≤25). Participants were requested to watch an amusing video. Based on the Facial Action Coding System, automated pattern recognition was used to detect smile episodes and assess their frequency, duration, genuineness, intensity, and extent of tooth show. Demographics, Big Five personality dimensions, and self-perceived smile esthetics-related quality of life were collected from all participants via questionnaires. Data were analyzed by mixed-model analysis and adjusted for possible confounders. RESULTS: Patients from the malocclusion and retention groups smiled significantly less than participants from the control group, with the duration of smiles and smiling time being around half those of control subjects. Smile genuineness, smile intensity, and teeth shown did not differ across groups. Personality traits did not differ significantly among the 3 groups, whereas the malocclusion group scored around 30% less for dental self-confidence than the other 2 groups. CONCLUSIONS: Patients with severe malocclusion tend to smile less, but the features of their smiles are similar to those without malocclusion. A lower propensity to smile in patients with a corrected malocclusion may persist after orthodontic treatment.

Automated detection of smiles as discrete episodes.

BACKGROUND: Patients seeking restorative and orthodontic treatment expect an improvement in their smiles and oral health-related quality of life. Nonetheless, the qualitative and quantitative characteristics of dynamic smiles are yet to be understood. OBJECTIVE: To develop, validate, and introduce open-access software for automated analysis of smiles in terms of their frequency, genuineness, duration, and intensity. MATERIALS AND METHODS: A software script was developed using the Facial Action Coding System (FACS) and artificial intelligence to assess activations of (1) cheek raiser, a marker of smile genuineness; (2) lip corner puller, a marker of smile intensity; and (3) perioral lip muscles, a marker of lips apart. Thirty study participants were asked to view a series of amusing videos. A full-face video was recorded using a webcam. The onset and cessation of smile episodes were identified by two examiners trained with FACS coding. A Receiver Operating Characteristic (ROC) curve was then used to assess detection accuracy and optimise thresholding. The videos of participants were then analysed off-line to automatedly assess the features of smiles. RESULTS: The area under the ROC curve for smile detection was 0.94, with a sensitivity of 82.9% and a specificity of 89.7%. The software correctly identified 90.0% of smile episodes. While watching the amusing videos, study participants smiled 1.6 (±0.8) times per minute. CONCLUSIONS: Features of smiles such as frequency, duration, genuineness, and intensity can be automatedly assessed with an acceptable level of accuracy. The software can be used to investigate the impact of oral conditions and their rehabilitation on smiles.

A qualitative meta-synthesis of research into patients' past experiences and perceptions of orthodontic treatment outcomes.

BACKGROUND: There is a growing body of evidence emphasizing the importance of research into patient-centred experience in orthodontics. Benefits following orthodontic treatment are mainly related to improved aesthetics and psychosocial outcomes. However, treatment experience from the perspective of orthodontic patients is yet to be fully understood. OBJECTIVE: To understand the past experiences and current perceptions of treatment outcomes of orthodontic patients. STUDY DESIGN: A qualitative meta-ethnography. SELECTION CRITERIA: Qualitative studies and mixed-methods articles with a distinct qualitative component presenting patients' perception of outcomes and overall experiences after an active course of orthodontic treatment were included. SEARCH METHODS: Comprehensive electronic searches were conducted in MEDLINE, Scopus, Web of Science, PsycINFO, and EMBASE up to May 2021, supplemented by grey literature and manual searches. DATA COLLECTION AND ANALYSIS: Two independent reviewers were involved in study selection, data extraction, and quality appraisal. The Critical Appraisal Skills Programme tool for qualitative research was used to assess the quality of included studies. Analysis of data was conducted using meta-ethnographic methods. RESULTS: Out of 801 retrieved search hits, six studies fulfilled the inclusion criteria and were included in the synthesis. The analysis revealed three main themes and associated sub-themes: (1) Reflection on the past treatment experience, (2) Patient satisfaction with treatment outcomes, and (3) Learning to live with retainers. LIMITATIONS: Results express patients' opinions shortly after treatment, and the long-term impact of orthodontic treatment is yet to be understood. CONCLUSIONS: Orthodontic patients mainly viewed their experiences and treatment results positively. Desirable aesthetic outcomes, psychosocial outcomes, and satisfaction with smiles were often reported in the studies reviewed. However, some barriers to optimal experiences were noticed concerning orthodontic retention. REGISTRATION: PROSPERO (CRD42020180121).

Public faith in science in the United States through the early months of the COVID-19 pandemic.

OBJECTIVES: Given the centrality of science over the course of the COVID-19 crisis, we evaluate changes in people's beliefs in the power of science in the United States over the first four months of the pandemic. STUDY DESIGN: Post-hoc analysis of cross-sectional survey data. METHODS: A convenience sample of 1327 participants was recruited through Amazon's Mechanical Turk service for three surveys carried out in 14-25 January, 27 March to 1 April, and 28-29 May of 2020. Respondents completed a ten-item instrument measuring different aspects of their perceptions of science including trust, interest, and faith (answer to the question: "How much do you agree with the following statement: Science can sort out any problem."). We conducted multivariate analysis of covariance (MANCOVA) with faith, interest, and trust as dependent variables, time as the independent variable, and political orientation and religiosity as between-subjects covariates. RESULTS: The data revealed that public levels of faith in science increased between January (M â€‹= â€‹3.2) and both March (M â€‹= â€‹3.42) and May (M â€‹= â€‹3.4). By contrast, we observed no changes in interest and trust in science over the same time period. CONCLUSIONS: We speculate that increases in faith in science during the first four months of the pandemic helped people cope with the uncertainty and existential anxiety resulting from this public health crisis.

Aversion to organs donated by suicide victims: The role of psychological essentialism.

People are known to be susceptible to psychological essentialism when reasoning about organ transplantation, believing that the mental characteristics of the donor will transfer to the recipient. Because psychological essentialism is exacerbated in negative social contexts (i.e., moral contagion bias), the effect may be especially apparent when people consider the impact of receiving organs from donors who died by stigmatized causes, such as suicide and homicide. In a forced-choice paradigm, participants overwhelmingly ranked a suicide victim as their least preferred donor, with accident victims being the most preferred donors and homicide victims the most common second choice. In a follow-up study, we investigated the psychological mechanisms underlying this unease about suicide donors. Compared to those who imagined receiving a heart from homicide or accident victims, participants who imagined a suicide donor expressed greater unease about the source of their transplant. The effect could not be explained by participants' rumination about the source of the transplant, or by the explicitly perceived stigma of suicide, but did depend on their essentialist beliefs. Those who believed that negative or neutral (but not positive) traits of the donor could transfer to them were more hesitant about receiving a heart from a suicide relative to other donors. These data suggest that the bias against suicide organ donors is moderated by socially relevant essentialist beliefs.