Measurement of vertical anterior teeth display and lip position at smiling in Kurdish population. Age and gender-based evaluation.

Statement of Problem: As part of the overall facial analysis, smile analysis is an essential component of diagnosis and treatment planning in the esthetic rehabilitation of a patient with missing anterior teeth. Purpose: The aim of this study was to investigate the effect of age and gender on the amount of maxillary anterior teeth and associated lip position during smiling in the Kurdish population to establish guidelines for rehabilitating edentulous patients. Material and methods: Video equipment was used to capture images of 80 Kurdish subjects divided into two groups by age and sex: Forty young subjects (20 women and 20 men aged 21-24 years), and another forty old subjects (20 women and 20 men aged 45-65 years). Three frames for each subject were selected: one representing the entire length of maxillary anterior teeth, another the posed smile frame and the third representing the spontaneous widest smile. These images were used to quantify a dentogingival exposure for each anterior tooth on either side using standardized measurement techniques. The Kruskal-Wallis test was used to evaluate and compare differences in teeth and gingival display and the Chi-square test was used to explore the frequency of smile line types (α = 0.05). Results: There were no significant age or sex differences in the anterior teeth display of posed smile. However, women displayed more maxillary anterior teeth in both age groups. The highest display was for lateral incisors, followed by central incisors and canine (61.3%, 58.9%, and 49.05% in the young group vs 62.05%, 54.5%, and 53.3% in the old group). On the other hand, a significant age difference was observed in dentogingival display of maxillary anterior teeth during a spontaneous smile, including mainly the lateral incisors length with their overlying gingiva (98.5%, 1.46 mm in young vs 92.1%, 0.47 mm in old). Women show insignificant excess gingival display than men. Low smile line (class IV) was the predominant type of smile in posed smiles (60%-62.5%). While the average smile line (class III) was the dominant type of young (52.5%) and the high (class II) of old (40%) in spontaneous smiles. Conclusions: Age influences the dental and gingival display of anterior teeth in spontaneous smiles but not in posed smiles. Women generally show more gingiva and teeth in all the parameters evaluated than men. The predominant type of smile changed from (class IV) in posed smile to (class III) of young and to (class II) of old subjects in a spontaneous smile. Dental treatments should be individually planned according to age-related dynamic norms.

Influência do Desvio da Linha Média Superior na Atratividade do Sorriso / Influence of Upper Midline Deviation on Smile Attractiveness / Influencia de la desviación de la línea media superior en el atractivo de la sonrisa

Resumo Introdução e objetivo: a análise do sorriso diante de um tratamento odontológico é imprescindível e deve sempre levar em consideração fatores como: idade do paciente, anomalias de tamanho e forma dos dentes, formato do rosto, lábios, cor, presença de diastemas, desvios de linha média dentária, entre outros. Investigar a possível influência do desvio da linha média superior na atratividade do sorriso em adolescentes. Métodos: foram utilizadas seis fotografias frontais de sorrisos posados de voluntários adolescentes tratados ortodonticamente que apresentavam uma oclusão aparentemente normal e a linha média dentária superior coincidente com a linha média facial e com a inferior. Cada fotografia real foi manipulada com auxílio do Adobe Photoshop 7.0, para obter-se fotografias com desvio de linha média superior de 1 a 4mm, totalizando 30 fotografias. Tais imagens foram analisadas por cirugiões-dentistas, alunos de odontologia e adolescentes leigos, os quais as classificaram levando em consideração a estética do sorriso. Para verificar a atratividade do sorriso foi utilizado a análise de variância (ANOVA) para a avaliação inter e intra-grupos, além da correlação de Pearson. Resultados: os grupos de alunos e cirurgiões-dentistas mostraram correlação negativa entre o desvio da linha media e a atratividade do sorriso (p≤0,05). Foi possível observar que não houve diferença estatisticamente significante na avaliação feita por adolescentes leigos independente do grau de desvio de linha média. Conclusão: desvios de linha média superior prejudicam a atratividade de sorriso quando avaliadas por pessoas que têm conhecimento sobre a área odontológica.

Abstract Introduction and objective: the analysis of the smile in the face of dental treatment is essential and must always take into account factors such as: age of the patient, anomalies in the size and shape of the teeth, face shape, lips, color, presence of diastema, dental midline deviations, between others. To investigate the possible influence of the deviation of the upper midline on the attractiveness of the smile in adolescents. Materials and methods: six frontal photographs in posed smile were selected from orthodontically treated adolescent volunteers who had an apparently normal occlusion and an upper dental midline coincident with facial and lower midline. Each real photograph was manipulated with the aid of Adobe Photoshop 7.0, in order to obtain photographs with an upper midline deviation of 1 to 4mm, totaling 30 photographs. Such images were analyzed by graduated dentists, dentistry students and lay adolescents, who classified them considering the aesthetics of the smile. To check the attractiveness of the smile, analysis of variance (ANOVA) was used for inter and intra-group evaluation, in addition to Pearson's correlation. Results: the groups of students and dentists showed a negative correlation between the deviation from the midline and the attractiveness of the smile (p ≤0.05). It was possible to observe that there was no statistically significant difference in the assessment made by lay adolescents, regardless of the degree of deviation from the midline. Conclusion: deviations from the upper midline impair the smile attractiveness when evaluated by people who are knowledgeable about the dental field.

Resumen Introducción y objetivo: el análisis de la sonrisa de cara al tratamiento odontológico es fundamental y siempre debe tener en cuenta factores como: edad del paciente, anomalías en el tamaño y forma de los dientes, forma de la cara, labios, color, presencia de diastemas, desviaciones de la línea media, entre otros. Investigar la posible influencia de la desviación de la línea media superior en el atractivo de la sonrisa en adolescentes. Materiales y métodos: se utilizaron seis fotografías frontales en sonrisa posada tomadas a adolescentes voluntarios tratados con ortodoncia que tenían oclusión aparentemente normal y línea media dentaria superior coincidente con línea media facial e inferior. Cada fotografía real fue manipulada con la ayuda de Adobe Photoshop 7.0, con el fin de obtener fotografías con una desviación de la línea media superior de 1 a 4 mm, totalizando 30 fotografías. Tales imágenes fueron analizadas por odontólogos graduados, estudiantes de odontología y adolescentes legos, quienes las clasificaron teniendo en cuenta la estética de la sonrisa. Para verificar el atractivo de la sonrisa, se utilizó el análisis de varianza (ANOVA) para la evaluación inter e intra-grupo, además de la correlación de Pearson. Resultados: los grupos de estudiantes y dentistas mostraron una correlación negativa entre la desviación de la línea media y el atractivo de la sonrisa (p ≤0.05). Se pudo observar que no hubo diferencia estadísticamente significativa en la evaluación realizada por los adolescentes legos independientemente del grado de desviación de la línea media. Conclusión: las desviaciones de la línea media superior perjudican el atractivo de la sonrisa cuando son evaluadas por personas que tienen conocimientos sobre el campo dental.

Kinematic Analysis of Smiles in the Healthy Pediatric Population Using 3-Dimensional Motion Capture.

INTRODUCTION: Facial normalcy, as measured with 2-dimensional or 3-dimensional photographs, has been documented in the healthy pediatric population. However, static images convey far from a complete representation of an individual's daily interactions with peers. Craniofacial surgery induces changes to soft or osseous tissues and thereby affects dynamic facial expression. To-date, there has not been rigorous, dynamic quantification of normal facial expression. In this study, we used 4-dimensional (4D) imaging to assess the facial expression of healthy children to provide a normative reference point for craniofacial surgeons. METHODS: A total of 36 healthy pediatric volunteers underwent 4D video recordings while performing a maximal voluntary smile. A face template containing 884 landmarks was registered and tracked throughout the videos using Dimensional Imaging software. Participants were divided into 2 smile groups: open-lip smile and closed-lip smile. Kinematic analysis of smiles was calculated for every landmark from its position in the resting frame to its terminal displacement. RESULTS: Composite smiles and Euclidean distance maps were generated displaying areas of greatest displacement near the oral commissures. There was significant difference between closed-lip and open-lip groups in regions of eyes and cheeks. In addition, the open-lip smile group demonstrated significantly greater displacement in the oral commissure on the left side compared to the right (P < .05); whereas, in the closed-lip group, the eyes and cheeks moved significantly more on the right side. CONCLUSION: This study presents an innovative method that can be used to evaluate facial expressions to help craniofacial surgeons restore functional movement in patients with facial anomalies.

Use of autonomous maximal smile to evaluate dental and gingival exposure.

OBJECTIVE: This study was performed to validate the autonomous maximal smile (AMS) as a new reference for evaluating dental and gingival exposure. METHODS: Digital video clips of 100 volunteers showing posed smiles and AMS at different verbal directives were recorded for evaluation a total of three times at 1-week intervals. Lip-teeth relationship width (LTRW) and buccal corridor width (BCW) were measured. LTRW represented the vertical distance between the inferior border of the upper vermilion and the edge of the maxillary central incisors. Intraclass correlation coefficients (ICCs) for reproducibility, and the m-value (minimum number of repeated measurements required for an ICC level over 0.75), were calculated. RESULTS: LTRW and BCW of the AMS were 1.41 and 2.04 mm, respectively, greater than those of the posed smile (p < 0.05), indicating significantly larger dental and gingival exposure in the AMS. The reproducibility of the AMS (0.74 to 0.77) was excellent, and higher than that of the posed smile (0.62 to 0.65), which had fair-to-good reproducibility. Moreover, the m-value of the AMS (0.88 to 1.05) was lower than that of the posed smile (1.59 to 1.85). CONCLUSIONS: Compared to the posed smile, the AMS shows significantly larger LTRW and BCW, with significantly higher reproducibility. The AMS might serve as an adjunctive reference, in addition to the posed smile, in orthodontic and other dentomaxillofacial treatments.

Use of autonomous maximal smile to evaluate dental and gingival exposure / 대한치과교정학회지

OBJECTIVE: This study was performed to validate the autonomous maximal smile (AMS) as a new reference for evaluating dental and gingival exposure. METHODS: Digital video clips of 100 volunteers showing posed smiles and AMS at different verbal directives were recorded for evaluation a total of three times at 1-week intervals. Lip-teeth relationship width (LTRW) and buccal corridor width (BCW) were measured. LTRW represented the vertical distance between the inferior border of the upper vermilion and the edge of the maxillary central incisors. Intraclass correlation coefficients (ICCs) for reproducibility, and the m-value (minimum number of repeated measurements required for an ICC level over 0.75), were calculated. RESULTS: LTRW and BCW of the AMS were 1.41 and 2.04 mm, respectively, greater than those of the posed smile (p < 0.05), indicating significantly larger dental and gingival exposure in the AMS. The reproducibility of the AMS (0.74 to 0.77) was excellent, and higher than that of the posed smile (0.62 to 0.65), which had fair-to-good reproducibility. Moreover, the m-value of the AMS (0.88 to 1.05) was lower than that of the posed smile (1.59 to 1.85). CONCLUSIONS: Compared to the posed smile, the AMS shows significantly larger LTRW and BCW, with significantly higher reproducibility. The AMS might serve as an adjunctive reference, in addition to the posed smile, in orthodontic and other dentomaxillofacial treatments.

Dimensional analyses of frontal posed smile attractiveness in Japanese female patients.

OBJECTIVE: To identify appropriate dimensional items in objective diagnostic analysis for attractiveness of frontal posed smile in Japanese female patients by comparing with the result of human judgments. MATERIALS AND METHODS: Photographs of frontal posed smiles of 100 Japanese females after orthodontic treatment were evaluated by 20 dental students (10 males and 10 females) using a visual analogue scale (VAS). The photographs were ranked based on the VAS evaluations and the 25 photographs with the highest evaluations were selected as group A, and the 25 photos with the lowest evaluations were designated group B. Then 12 dimensional items of objective analysis selected from a literature review were measured. Means and standard deviations for measurements of the dimensional items were compared between the groups using the unpaired t-test with a significance level of P < .05. RESULTS: Mean values were significantly smaller in group A than in group B for interlabial gap, intervermilion distance, maxillary gingival display, maximum incisor exposure, and lower lip to incisor (P < .05). CONCLUSIONS: Significant differences were observed only in the vertical dimension, not in the transverse dimension. Five of the 12 objective diagnostic items were correlated with human judgments of the attractiveness of frontal posed smile in Japanese females after orthodontic treatment.

Establishment of a new relationship between posed smile width and lower facial height: A cross-sectional study.

OBJECTIVE: The present study is intended to add a new parameter that would be useful in orthodontic clinical evaluation, treatment planning, and determination of vertical dimension (at occlusion). MATERIALS AND METHODS: Standardized videographic recording of 79 subjects during posed smile was captured. Each video was then cut into 30 photos using the free studio software. The widest commissure-to-commissure posed smile frame (posed smile width [SW]) was selected as one of 10 or more frames showing an identical smile. Lower third of the face is measured from subnasale to soft tissue menton using a digital vernier caliper. Two values were then compared. Ratio between lower facial height and posed SW was calculated. RESULTS: The co-relation between smiling width and lower facial height was found to be statistically significant (P < 0.01). The ratio of lower facial height and smiling width was calculated as 1.0016 with a standard deviation (SD) = 0.04 in males and 1.0301 with an SD = 0.07 in females. The difference between the mean lower facial height in males and females was statistically significant with a t = 10.231 and P = 0.000. The difference between the mean smiling width in males and females was also statistically significant with a t = 5.653 and P = 0.000. CONCLUSION: In class I subjects with pleasing appearance, normal facial proportions, normal overjet and overbite, and average Frankfort mandibular angle, the lower facial height (subnasale to soft tissue menton) is equal to posed SW.

Upper canine inclination influences the aesthetics of a smile.

This current study investigated which angle of canine inclination (angle between canine tooth axis (CA-line) and the line between the lateral canthus and the ipsilateral labial angle (EM-line)) is perceived to be most attractive in a smile. The second objective was to determine whether laymen and dental experts share the same opinion. A Q-sort assessment was performed with 48 posed smile photographs to obtain two models of neutral facial attractiveness. Two sets of images (1 male model set, 1 female model set), each containing seven images with incrementally altered canine and posterior teeth inclinations, were generated. The images were ranked for attractiveness by three groups (61 laymen, 59 orthodontists, 60 dentists). The images with 0° inclination, that is CA-line (maxillary canine axis) parallel to EM-line (the line formed by the lateral canthus and the ipsilateral corner of the mouth) (male model set: 54·4%; female model set: 38·9%), or -5° (inward) inclination (male model set: 20%; female model set: 29·4%) were perceived to be most attractive within each set. Images showing inward canine inclinations were regarded to be more attractive than those with outward inclinations. Dental experts and laymen were in accordance with the aesthetics. Smiles were perceived to be most attractive when the upper canine tooth axis was parallel to the EM-line. In reconstructive or orthodontic therapy, it is thus important to incline canines more inwardly than outwardly.

Gender differences in posed smiles using principal component analysis.

OBJECTIVES: The purpose of this study was to clarify gender differences in posed smiles using principal component analysis (PCA). MATERIALS AND METHODS: Fourteen adult volunteers, 7 males and 7 females, were enrolled. Using the motion analyzing system we developed, range images and 5 × 5 virtual grids were produced across the whole sequence while the volunteers were asked to smile. Two sets of all intersections of the virtual grids captured while the subject was smiling were regarded as PCA variables. Discriminate analysis was then applied to compare the males and females. RESULTS: The first and second principal component scores (PCSs) were plotted on the x-axis and y-axis, respectively. The center of gravity of the PCSs is shown by the plus on the x-axis and minus on the y-axis for the males and by the minus on the x-axis and the plus on the y-axis for the females. Discriminate analyses of the PCSs revealed a correct gender classification rate of 74.4% for posed smiles. CONCLUSIONS: While the sample size is too small to extrapolate from these results, we can conclude that PCA can be used to identify gender differences while smiling.

A study on the smile characteristics of the subjects with different types of malocclusion / 实用口腔医学杂志

Objective:To compare the smile characteristics of the subjects with different types of malocclusion.Methods:1 80 sub-jects with classⅠ(n =60),classⅡ(n =60)and class Ⅲ(n =60)malocclusion at the age of 1 8 to 25 years were included.The smile vidioes and posed smile images of the subjects were acquired.Smile quantitative evaluation indexes were measured and analysed.Re-sults:There were statistical differences in smile indexes and the amount of the gingival exposure in classⅡ subjects between the male and female(P classⅠ >classⅢ,smile index of class Ⅲ was greater than that of class Ⅰ and class Ⅱ,the teeth exposure of class Ⅱ was less than that of class Ⅰand class Ⅲ.Conclusion:Malocclusion types may affect smile characteristics.

Three-dimensional intra-rater and inter-rater reliability during a posed smile using a video-based motion analyzing system.

OBJECTIVES: The purpose of this study was to determine the three-dimensional reproducibility of lip movement during a posed smile using a video-based motion analyzing system. MATERIALS AND METHODS: In six adult volunteers (4 males and 2 females), the lip motions during a posed smile were recorded six times. Using our recently-developed motion analyzing system, range images were produced across the whole sequence during the posed smile. Virtual grids of 5 × 5 were fitted onto the surfaces, and the three-dimensional coordinates of the intersections of these grids were then computed. The magnitude of the shift of the intersections during smiling was calculated and summed in each area. Intraclass correlation coefficients (ICC), ICC (1,1) for intra-rater reliability and ICC (2,1) for inter-rater reliability were calculated. The number of repeated measurements necessary for an ICC level beyond 0.8 was determined using the formula of Spearman-Brown. RESULTS: The ICC (1,1) and ICC (2,1) ranged from 0.71 to 0.83 and from 0.77 to 0.99, respectively. The number of repeated measurements necessary for an ICC beyond 0.8 was 2. CONCLUSIONS: From the present study, both the three-dimensional intra-rater and inter-rater reliabilities during a posed smile were considered to be relatively high, and enough reliability could be expected by calculating the average of the values measured two times. However, the sample size was very small, this could not be generalized simplistically.