Diferencias en la morfología ósea entre el lado desplazado y contralateral en pacientes con asimetría facial: Estudio 3D-TC / Bone morphology differences between displaced and contralateral side in patients with facial asymmetry: 3D-CT study / Diferenças na morfologia óssea entre o lado deslocado e o lado contralateral em pacientes com assimetria facial: estudo 3D-CT

Resumen Introducción y objetivo: Las asimetrías faciales son un motivo de consulta estética y funcional frecuente (35%) en la consulta de cirugía maxilofacial. Describir las variaciones morfológicas óseas craneofaciales en pacientes con asimetría facial. Materiales y métodos: Estudio descriptivo, en 53 pacientes (23 hombres, 30 mujeres) con asimetría facial. Mediante tomografía axial computarizada y reconstrucción 3D se describieron las características anatómicas del lado largo que expone la asimetría y del lado contralateral (lado corto hacia donde se desvía la mandíbula), en los planos frontal y sagital. Resultados: Se identificaron cinco categorías de asimetría facial: Elongación hemimandibular, (EH, n = 26; 49%) Hiperplasia hemimandibular (n = 4; 7.5%), Prognatismo mandibular asimétrico (PMA, n = 14; 25,4%), Asimetría de cavidad glenoidea, (n = 2; 3.8%) y laterognatismo funcional (n = 7; 13,2%). En 64.1% de los casos la desviación mandibular era del lado izquierdo. En el plano frontal se observó mayor distancia desde el plano medio sagital a los puntos malar, yugal y gonion en el lado contralateral (p<0.05). En el plano sagital, el ancho de la rama mandibular era mayor en el lado desplazado (p<0.05) y la longitud del cuerpo mandibular era mayor en el lado contralateral (p<0.001). en las asimetrías más prevalentes (EH y PMA), la presencia de una desviación de la sínfisis > 5.1mm da mayor probabilidad de EH [OR: 4.05, IC95%: 1.02-16.0]. Conclusión: Los pacientes con asimetría facial presentaron diferencias morfológicas craneofaciales en los planos frontal y sagital, que ayudan a identificar las diferentes entidades que causan esta alteración.

Abstract Introduction and objetive: Facial asymmetries are a frequent esthetic and functional problem.To describe the craniofacial morphologic variability, in patients with facial asymmetry. Materials and methods: 53 patients (23 men and 30 women) with facial asymmetry were studied using 3D computed axial tomography reconstruction. The long side, exhibiting the asymmetry, and the contralateral side (shorter side presenting mandibular deviation), were compared in frontal and sagittal planes. Results: Five kinds of facial asymmetry were identified: Hemimandibular elongation (HE, n = 26; 49%) Hemimandibular hyperplasia (n = 4; 7.5%), asymmetric mandibular prognathism (PMA, n = 14; 25.4%), glenoid fossa asymmetry (n = 2; 3.8%) and functional laterognathism. (n = 7; 13,2%). 64.1% cases had left side mandibular deviation. In the frontal plane the distance from the mid-sagittal plane to malar, yugal and gonion point was higher in the contralateral side (p<0.05). In the sagittal plane mandibular ramus width was higher in the displaced side (p<0.05) and mandibular body length was higher in the contralateral side (p<0.001). Regarding the two most prevalent groups (HE and AMP), the presence of a symphysis deviation > 5.1mm is associated to higher probability of having HE [OR: 4.05, CI 95%: 1.02-16.0]. Conclusion: Patients with facial asymmetry present craniofacial morphological side differences in the frontal and sagittal planes, useful to identify different entities that cause this alteration.

Resumo Introdução y objectivo: As assimetrias faciais são um motivo frequente de consulta estética e funcional (35%) na cirurgia maxilofacial. Descrever as variações morfológicas do osso craniofacial em pacientes com assimetria facial. Materiais e métodos: Estudo descritivo, em 53 pacientes (23 homens, 30 mulheres) com assimetria facial. Através de tomografia axial computorizada e reconstrução 3D, foram descritas as características anatómicas do lado longo expondo a assimetria e do lado contralateral (lado curto para o qual a mandíbula é desviada), nos planos frontal e sagital. Resultados: Foram identificadas cinco categorias de assimetria facial: alongamento hemimandibular, (EH, n = 26; 49%) hiperplasia hemimandibular, (n = 4; 7,5%), prognatismo assimétrico mandibular, (PMA, n = 14; 25,4%), assimetria da cavidade glenoidal, (n = 2; 3,8%) e laterognatismo funcional, (n = 7; 13,2%). Em 64,1% dos casos, o desvio mandibular foi do lado esquerdo. No plano frontal havia uma maior distância do plano médio sagital aos pontos malar, yugal e gonion do lado contralateral (p<0,05). No plano sagital, a largura do ramo mandibular foi maior no lado deslocado (p<0,05) e o comprimento do corpo mandibular foi maior no lado contralateral (p<0,001). Nas assimetrias mais prevalentes (HD e PMA), a presença de um desvio da sínfise > 5,1mm dá uma maior probabilidade de HD [OU: 4,05, IC 95%: 1,02-16,0]. Conclusão: Os pacientes com assimetria facial apresentaram diferenças morfológicas craniofaciais nos planos frontal e sagital, que ajudam a identificar as diferentes entidades causadoras desta alteração.

Assessment of reproducibility and reliability of facial expressions using 3D handheld scanner.

PURPOSE: The three-dimensional morphological analysis of facial expressions has been becoming increasingly common and hand-held three-dimensional scanners can be advantageous in data acquisition due to their mobility. The aim of the present study was to test intra-subject, intra-observer and inter-observer reproducibility and reliability of a hand-held scanner during facial expressions. MATERIALS AND METHODS: In order to investigate intra-subject reproducibility and reliability, we performed face scanning two times on 30 healthy subjects at three-month intervals. In addition, two observers scanned twice the face of 10 healthy subjects consecutively to evaluate intra-observer and inter-observer differences. Scannings were performed during facial expressions. Face asymmetry and severity of facial expression were determined using root mean square (RMS) value. Repeated-measurement ANOVA was used to test the reproducibility and correlation coefficient to determine the reliability of the facial expressions. RESULTS: The mean RMS values measured at different times were not significantly different for any facial expression (p > 0.05). The reliability of the measurements was variable depending on the facial expression (r = 0.47 and 0.98, p < 0.05). CONCLUSIONS: Our study may contribute to the development of new techniques for examining facial expressions. Hereby, morphological analysis may be possible in the clinic and at the bedside without the need for laboratory conditions.

Identification of five novel genetic loci related to facial morphology by genome-wide association studies.

BACKGROUND: Face morphology is strongly determined by genetic factors. However, only a small number of genes related to face morphology have been identified to date. Here, we performed a two-stage genome-wide association study (GWAS) of 85 face morphological traits in 7569 Koreans (5643 in the discovery set and 1926 in the replication set). RESULTS: In this study, we analyzed 85 facial traits, including facial angles. After discovery GWAS, 128 single nucleotide polymorphisms (SNPs) showing an association of P < 5 × 10- 6 were selected to determine the replication of the associations, and meta-analysis of discovery GWAS and the replication analysis resulted in five genome-wide significant loci. The OSR1-WDR35 [rs7567283, G allele, beta (se) = -0.536 (0.096), P = 2.75 × 10- 8] locus was associated with the facial frontal contour; the HOXD1-MTX2 [rs970797, A allele, beta (se) = 0.015 (0.003), P = 3.97 × 10- 9] and WDR27 [rs3736712, C allele, beta (se) = 0.293 (0.048), P = 8.44 × 10- 10] loci were associated with eye shape; and the SOX9 [rs2193054, C allele, beta (se) (ln-transformed) = -0.007 (0.001), P = 6.17 × 10- 17] and DHX35 [rs2206437, A allele, beta (se) = -0.283 (0.047), P = 1.61 × 10- 9] loci were associated with nose shape. WDR35 and SOX9 were related to known craniofacial malformations, i.e., cranioectodermal dysplasia 2 and campomelic dysplasia, respectively. In addition, we found three independent association signals in the SOX9 locus, and six known loci for nose size and shape were replicated in this study population. Interestingly, four SNPs within these five face morphology-related loci showed discrepancies in allele frequencies among ethnic groups. CONCLUSIONS: We identified five novel face morphology loci that were associated with facial frontal contour, nose shape, and eye shape. Our findings provide useful genetic information for the determination of face morphology.

Identification of new morphological differences between Chinese and Caucasian faces and influence of BMI on these characteristics.

BACKGROUND: Concepts of beauty are more and more globalised leading to the homogenisation of the physical appearance. It is therefore important to identify morphological characteristics of ethnic groups. We compare faces from Chinese and Caucasian women, identify morphological differences that were not documented yet and study the influence of BMI on these differences. METHODS: The study was carried on groups of 60 women: a Chinese and a Caucasian group. Both included two equal sub-groups: normal BMI and higher BMI. Face widths were measured from individual pictures and from reconstructed average faces obtained using a new reconstruction algorithm. Cheek/chin and neck/chin angles were determined from individual pictures. Topography of the cheekbone and temple face was determined by fringe projection technique. Ultrasound analysis allows measurements of hypodermis thickness. RESULTS: Our innovative average face reconstruction algorithm produced images of a yet unequalled quality with width characteristics similar to those of individual pictures. Analysis shows that faces of Chinese women are larger and rounder. They present other differences that were so far unidentified. Finally, overweight impacts differently Chinese and Caucasian women faces and has greater influence on Chinese women faces.

Personality and facial morphology: Links to assertiveness and neuroticism in capuchins (Sapajus [Cebus] apella).

Personality has important links to health, social status, and life history outcomes (e.g. longevity and reproductive success). Human facial morphology appears to signal aspects of one's personality to others, raising questions about the evolutionary origins of such associations (e.g. signals of mate quality). Studies in non-human primates may help to achieve this goal: for instance, facial width-to-height ratio (fWHR) in the male face has been associated with dominance not only in humans but also in capuchin monkeys. Here we test the association of personality (assertiveness, openness, attentiveness, neuroticism, and sociability) with fWHR, face width/lower-face height, and lower face/face height ratio in 64 capuchins (Sapajus apella). In a structural model of personality and facial metrics, fWHR was associated with assertiveness, while lower face/face height ratio was associated with neuroticism (erratic vs. stable behaviour) and attentiveness (helpfulness vs. distractibility). Facial morphology thus appears to associate with three personality domains, which may act as a signal of status in capuchins.