The Role of the Posed Smile in Overall Facial Esthetics

Objective:To evaluate the role of the posed smile in overall facial esthetics, as determined by laypersons and orthodontists.Materials and Methods:Twenty orthodontists and 20 lay evaluators were asked to perform six Q-sorts on different photographs of 48 white female subjects. The six Q-sorts consisted of three different photographs for each of two time points (pre- and posttreatment), as follows: (1) smile-only, (2) face without the smile, and (3) face with the smile. The evaluators determined a split-line for attractive and unattractive images at the end of each Q-sort. The proportions of attractive patients were compared across Q-sorts using a Wilcoxon signed-rank test for paired data. The evaluators also ranked nine facial/dental characteristics at the completion of the six Q-sorts.Results:Evaluators found the pretreatment face without the smile to be significantly more attractive than the face with the smile or the smile-only photographs. Dissimilar results were seen posttreatment; there was not a significant difference between the three posttreatment photographs. The two panels agreed on the proportion of “attractive” subjects but differed on the attractiveness level of each individual subject.Conclusions:The presence of a malocclusion has a negative impact on facial attractiveness. Orthodontic correction of a malocclusion affects overall facial esthetics positively. Laypeople and orthodontists agree on what is attractive. Overall facial harmony is the most important characteristic used in deciding facial attractiveness.     

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.     

Cephalometric characteristics of postorthodontic female patients with attractive and unattractive frontal posed smiles

Objectives:To identify differences in skeletal, dental, and soft-tissue morphology between postorthodontic patients with attractive and unattractive frontal posed smiles.Materials and Methods:The attractiveness of close-up photographs of frontal posed smiles in 100 adult female patients after conventional orthodontic treatment was evaluated by 20 dental students (10 men, 10 women) using a visual analogue scale. Posttreatment cephalograms of the 20 patients with the most attractive smiles (attractive group; mean age 23.75 ± 3.35 years) and the 20 patients with least attractive smiles (unattractive group; mean age 23.11 ± 4.45 years) were selected, and 41 measurements were made and compared between groups using the Mann-Whitney U-test (P < .05).Results:When compared with the attractive group, the unattractive group exhibited greater values for sella-nasion plane to mandibular plane, palatal plane to mandibular plane, anterior facial height, lower facial height, and lower facial height/anterior facial height as skeletal measurements; for occlusal plane to sella-nasion plane, palatal plane to occlusal plane, and maxillary central incisor to palatal plane as dental measurements; and for lower face, upper lip length, and upper lip superior to palatal plane as soft-tissue measurements.Conclusions:Cephalometric analysis revealed that postorthodontic Japanese female patients with unattractive frontal posed smiles are characterized by a hyperdivergent skeletal pattern with extruded maxillary incisors and a steep occlusal plane, accompanied by a longer upper lip than patients achieving attractive posed frontal smiles.     

Assessment of orthodontic treatment need: a comparison of study models and facial photographs

Abstract – Objectives: The current study aims to examine how orthodontic treatment need is prioritized depending upon whether dental study models or facial photographs are used as the means of assessment. Methods: A group of three orthodontists and three postgraduate orthodontic students assessed: (i) dental attractiveness; and (ii) need for orthodontic treatment in 40 subjects (19 males, 21 females). The 40 subjects displayed a range of malocclusions. Separate assessments were made from study models and facial photographs. Results: There was a bias towards higher scores for dental attractiveness from facial photographs compared with assessment of study casts, for all examiners. This was statistically significant for five of the six examiners (P = 0.001–0.101). The need for orthodontic treatment was rated as 20% higher from study models compared with facial photographs (P < 0.001); overall the level of need for orthodontic treatment was rated as 18.9% higher from study models compared with facial photographs (P < 0.001). Reproducibility analyses showed that there was a considerable variation in the intra‐ and inter‐examiner agreement. Conclusions: This study shows that a group of three orthodontists and three postgraduate students in orthodontics: (i) rated orthodontic treatment need higher from study models compared with facial photographs and; (ii) rated dental attractiveness higher from facial photographs compared with study models. It is suggested that the variable intra‐examiner agreement may result from the assessment of orthodontic treatment need and dental attractiveness in the absence of any specific assessment criteria. The poor reproducibility of assessment of orthodontic treatment need and dental attractiveness in the absence of strict criteria may suggest the need to use an appropriate index.     

The role of the golden proportion in the evaluation of facial esthetics

Objective:To demonstrate if one or more golden relationships between different measurements of the human face exist.Materials and Methods:To make our measurements, we used three-dimensional (3D) stereophotogrammetry, which has proved to be the “gold standard” in the field of facial anthropometry. We obtained 3D stereophotogrammetric facial acquisitions of 400 healthy young adult subjects, then had them scored by an Evaluation Jury. Each subject received an esthetic evaluation ranging from 0 to 40. Individuals with a score larger than 28 were considered very attractive (VA), and individuals with a score lower than 12 were considered not attractive (NA). Fifteen subjects per group were chosen by chance, with a final total group of 60 subjects: 15 VA males, 15 NA males, 15 VA females, and 15 NA females. For each subject, a set of facial distances was obtained from the stereophotogrammetric facial reconstruction, and 10 ratios were computed. The effects of sex and attractiveness were tested by analysis of variance. Additionally, Student''s t-tests verified if the ratios were statistically different from the golden ratio.Results:For nine ratios, no significant effects of sex or attractiveness were found. Only the eye-mouth distance/height of the mandible ratio was significantly influenced by sex (P  =  .035) and attractiveness (P  =  .032). Seven out of 10 ratios were statistically different from the hypothetical value of 1.618, and only three of them were similar to the golden ratio.Conclusions:Ratios between 3D facial distances were not related to attractiveness. Most of the facial ratios were different from the golden ratio.     

The effect of treatment on facial attractiveness.

Pretreatment and posttreatment frontal and profile slides of 13 orthodontic camouflage and 13 orthognathic surgery patients were shown to three panels of judges: an orthodontic, an oral surgery, and a "lay" panel of first-semester dental students. Each judge rated the facial attractiveness of the pretreatment and posttreatment views of each patient using a visual analog scale. A mean pretreatment and posttreatment score was then calculated for each treatment group for each judge. Paired t tests were used to compare the treatment groups and time periods. The orthodontic camouflage group was rated as significantly more attractive than the orthognathic surgery patients before treatment. There was no significant change in the facial attractiveness mean score for the orthodontic group, whereas the orthognathic surgery group was rated as showing a significant improvement. However, the orthognathic surgery group was still rated as being significantly less attractive after treatment than the orthodontics-only group.     

Visual attention during the evaluation of facial attractiveness is influenced by facial angles and smile

Objective:To examine the changes in visual attention influenced by facial angles and smile during the evaluation of facial attractiveness.Materials and Methods:Thirty-three young adults were asked to rate the overall facial attractiveness (task 1 and 3) or to select the most attractive face (task 2) by looking at multiple panel stimuli consisting of 0°, 15°, 30°, 45°, 60°, and 90° rotated facial photos with or without a smile for three model face photos and a self-photo (self-face). Eye gaze and fixation time (FT) were monitored by the eye-tracking device during the performance. Participants were asked to fill out a subjective questionnaire asking, “Which face was primarily looked at when evaluating facial attractiveness?”Results:When rating the overall facial attractiveness (task 1) for model faces, FT was highest for the 0° face and lowest for the 90° face regardless of the smile (P < .01). However, when the most attractive face was to be selected (task 2), the FT of the 0° face decreased, while it significantly increased for the 45° face (P < .001). When facial attractiveness was evaluated with the simplified panels combined with facial angles and smile (task 3), the FT of the 0° smiling face was the highest (P < .01). While most participants reported that they looked mainly at the 0° smiling face when rating facial attractiveness, visual attention was broadly distributed within facial angles.Conclusions:Laterally rotated faces and presence of a smile highly influence visual attention during the evaluation of facial esthetics.     

Evaluation of soft tissue changes around the lips after bracket debonding using three-dimensional stereophotogrammetry

Objective:To evaluate the changes in soft tissue around the lips after orthodontic bracket debonding using three-dimensional (3-D) stereophotogrammetry.Materials and Methods:3-D facial images of 20 subjects (10 men and 10 women; mean age, 26.81 ± 7.23 years) were taken with a white light scanner before and after debonding the labial brackets. Two images acquired from each subject were superimposed, and 15 soft tissue landmarks around the lips were plotted and analyzed. Statistical analysis was performed using both paired and independent t-tests (P < .05).Results:There were no significant changes in position of any landmark on the x (left-right)- or y (vertical)-axes after removal of the brackets. However, the landmarks in the oral commissures and lower lip (LLP, −0.55 mm; Li, −0.44 mm; Ch-L, −0.56 mm, all P < .05) on the z (anteroposterior)-axis showed statistically significant differences. There were no significant positional changes of most landmarks on the x-, y-, or z- axes after bracket removal among the various genders and lip thicknesses.Conclusions:There was a slight retrusion in the oral commissure and lower lip areas after debonding, but no changes were found in the upper lip area. This study showed that 3-D stereophotogrammetry can be useful in evaluating facial soft tissue changes in orthodontic patients.     

Self-Perception of Dentofacial Attractiveness among Patients Requiring Orthognathic Surgery

Objective:To test the hypothesis that the self-perception of dental and facial attractiveness among patients requiring orthognathic surgery is no different from that of control patients.Materials and Methods:Happiness with dental and facial appearance was assessed using questionnaires completed by 162 patients who required orthognathic treatment and 157 control subjects. Visual analog scale, binary, and open response data were collected. Analysis was carried out using a general linear model, logistic regression, and chi-square tests.Results:Orthognathic patients were less happy with their dental appearance than were controls. Class II patients and women had lower happiness scores for their dental appearance. Among orthognathic patients, the “shape” and “prominence” of their teeth were the most frequent causes of concern. Older subjects, women, and orthognathic patients were less happy with their facial appearance. Class III orthognathic patients, older subjects, and women were more likely to have looked at their own face in profile. A greater proportion of Class II subjects than Class III subjects wished to change their appearance.Conclusions:The hypothesis is rejected. The findings indicate that women and patients requiring orthognathic surgery had lower levels of happiness with their dentofacial appearance. Although Class II patients exhibited the lowest levels of happiness with their dental appearance, there was some evidence that concerns and awareness about their facial profile were more pronounced among the Class III patients.     

Artificial Neural Network Modeling for Deciding if Extractions Are Necessary Prior to Orthodontic Treatment

Objective:To construct a decision-making expert system (ES) for the orthodontic treatment of patients between 11 and 15 years old to determine whether extraction is needed by using artificial neural networks (ANN). Specifically, we will uncover the factors that affect this decision-making process.Methods:A total of 200 subjects were chosen; among them, 120 were accepted for extraction treatments, and 80 were chosen for nonextraction treatments. For each case, 23 indices were selected. A 23-13-1 Back Propagation (BP) ANN model was constructed, and the data for 180 patients were aggregated to constitute the training set. Data for the other 20 patients were used as the testing set.Results:When data from the 180 patients that had been trained were tested, the result was 100%, as expected. The untrained data from 20 patients in the testing set were 80% correct (ie, 16 cases were forecasted successfully). In the meantime, the relative contributions of the 23 input indices to the final output index (extraction/nonextraction) were calculated. “Anterior teeth uncovered by incompetent lips” and “IMPA (L1-MP)” were the two indices that gave the biggest contributions sequentially; the index of FMA (FH-MP) gave the smallest contribution.Conclusions:(1) The constructed artificial neural network in this study was effective, with 80% accuracy, in determining whether extraction or nonextraction treatment was best for malocclusion patients between 11 and 15 years old; (2) when the clinician is predicting whether an orthodontic treatment requires extraction, the indices “anterior teeth uncovered by incompetent lips” and “IMPA (L1-MP)” should be taken into consideration first.     

Lip Morphology Changes Following Orthognathic Surgery for Class III Malocclusion

Objectives:To test the hypothesis that there is no difference in the morphology of the lips and to determine the degree of improvement in the smile after orthognathic surgery for Class III malocclusion.Materials and Methods:The sample subjects included 30 adult female patients with dento-skeletal Class III malocclusion and 28 adult female volunteers with normal occlusion. Frontal facial photographs were taken before and after treatment, and 35 landmarks were placed on each tracing made from the frontal facial photograph. Thereafter, the landmarks were digitized into an x and y coordinate system with the subnasal point as the origin. The pretreatment rest and smile conditions were compared with the posttreatment conditions, respectively, using paired t-tests. In addition, two sample t-tests were used to test for differences between groups.Results:Both the upper and lower lips in the smiles of the Class III pretreatment group were positioned downward, and the upward movement of the upper lip and commissure points were smaller compared with the control group. When smiling, the horizontal direction of the mouth corners was statistically significantly different between the pretreatment and posttreatment conditions, whereas these were wider in the posttreatment than in the pretreatment conditions. These characteristics of the Class III smile improved after orthognathic treatment, but the differences with the control group remained unchanged immediately after treatment.Conclusion:The hypothesis is rejected. The soft tissue morphology of patients with dento-skeletal Class III malocclusion shows a significant improvement after orthognathic surgery.     

Influence of lower facial height changes on frontal facial attractiveness and perception of treatment need by lay people

Objective:To test the hypothesis that lower facial height has no influence on frontal facial attractiveness and treatment need perception of lay people.Materials and Methods:Frontal facial silhouettes of a man and a woman with normal lower facial height values (male: 81.5 mm; female: 70.5 mm) were modified by increasing and decreasing their lower facial heights in steps of 1 mm to obtain frontal images with different lower facial height alterations ranging from +6 mm to −6 mm for each sex. A panel of 100 lay people scored each silhouette''s attractiveness on a 100-mm visual analogue scale (VAS) and also indicated whether they would seek treatment if the image represented their own. The Wilcoxon signed rank test was used to compare the VAS scores.Results:Unaltered ±1-mm and ±2-mm silhouettes got the highest VAS scores. Scores were significantly lower (P ≤ .001) as the divergence from the normal value exceeded 2 mm. Beyond +3 mm and −4 mm in females and +4 mm and −3 mm in males the difference between the scores became statistically insignificant. At ±4 mm, more than 75% of the raters elected to have treatment.Conclusion:The hypothesis was rejected.     

Three-dimensional cone beam computed tomographic image reorientation using soft tissues as reference for facial asymmetry diagnosis

Objective:To investigate discrepancies in results of facial asymmetry analysis using different cone beam computed tomography (CBCT) image reorientation methods and the effectiveness of soft tissue as a reorientation reference for analysis of facial asymmetry.Materials and Methods:An asymmetric group of 30 patients with 4 mm or more of chin point (menton [Me]) deviation and a symmetric group of 30 patients with less than 4 mm of deviation of Me were chosen as study subjects. Three orientation methods were used to calculate and compare Me deviation values of the 60 subjects. Two methods used only skeletal landmarks for reference, and one method included the soft tissue landmarks around the eye. Preferences of an expert group for the facial midline as determined by each reorientation method were also examined.Results:The examinations showed significant discrepancies in Me deviation values between the three reorientation methods. The expert group showed the greatest preference for the facial midline reorientation method that incorporated soft tissue landmarks of the eye.Conclusions:These study findings suggest that the inclusion of soft tissue landmarks, especially those around the eyes, is effective for three-dimensional CBCT image reorientation for facial asymmetry analysis.     

The perception of facial aesthetics in a young Spanish population

Improved facial aesthetics is one aim of orthodontic treatment. This study was designed to determine if the faces considered more beautiful in a young population exhibit the same parameters used by orthodontists to assess successful results. A panel of 34 laypeople (30 females and 4 males) evaluated a set containing one frontal, one frontal during smiling, and one profile photograph of 89 students (77 females and 12 males) on a 5-point attractiveness scale, in relation to a set of reference photographs. For each photographic set, the mean and final scores were calculated. Once the sample was established, 11 subjects (9 females and 2 males) with the highest final facial aesthetic score were selected and cephalometric analysis was performed. All cephalometric measurements were within the norm for the total sample. When the sample was divided by gender, Wilcoxon's W non-parametric test showed significant differences between the male and female photographs; while females tended to a Class II malocclusion, with the mandible slightly retrusive to the maxilla, males tended to a Class III and showed a straighter profile with a prominent chin; the face height ratio was higher in males. There were no significant differences between genders for lower lip to E plane. The findings show that the faces considered more attractive fulfilled the cephalometric and facial norms.     

Smile esthetics from odontology students' perspectives

Objectives:To analyze the perception of smile esthetics and its alterations in dental degree students; to determine whether there are differences in that perception among students in different study years on those courses and between genders; and to determine if the circumstance of having received prior orthodontic treatment could influence that perception.Material and Methods:Students (n = 192) in different study years of the dental degree course at the University of Valencia, Spain, analyzed two photographs of a patient in which, by means of computer software, midline diastema, upper and lower midlines, crown length of the maxillary right central incisor, occlusal cant, and “gummy” smile were altered. Students assessed the photographs on a scale from 1 to 10. Statistical analyses for assessing each group''s level of perception were carried out.Results:After checking the validity of the study, it was observed that the students'' ability to detect alterations in smile esthetics did not improve over their degree courses, given that the differences do not present a linear development. There were no differences between genders and between those who had or had not undergone an orthodontic treatment.Conclusions:There are no statistically significant differences between the results of students in different study years or between genders. The circumstance of having undergone prior orthodontic treatment is not a determining factor in the ability to perceive such anomalies.     

Quantifying faces three-dimensionally in orthodontic practice

PurposeThe purpose of this study was to formulate and demonstrate a method for quantifying and visualizing the three-dimensional (3-D) configuration of the soft tissues of the face at rest to facilitate a quantitative and instantaneous understanding of a patient's static facial form characteristics.Materials and methods3-D facial images of 200 Japanese adult volunteers at rest were recorded using a 3-D photogrammetric system. For each participant, a wire mesh fitting was conducted based on the assignment of landmarks to each 3-D facial image. This method generated 6,017 points on the wire mesh (i.e., the nodes of the fitted mesh). For each point, the mean and standard deviation were calculated and used for patient evaluation. The system performance was exemplified with three orthodontic patients with skeletal Class II and III malocclusions and laterotrusion.ResultsThree patients with severe skeletal Class II and III deformities and laterotrusion were evaluated with the proposed method.ConclusionA clinical method for practitioners to quantify and visualize the soft tissues of a patient's face in 3 dimensions has been presented with clinical applications and considerations. This method allows practitioners to evaluate how patients' facial characteristics differ from normative faces.     

Influence of facial type on attractiveness of vertical canine position from the perspective of orthodontists and laypeople

ObjectivesTo evaluate the attractiveness of changes in vertical position of maxillary canines in frontal smiles of different facial types, and to evaluate the esthetic perceptions of orthodontists and laypeople, and the influence of facial type on these perceptions.Materials and MethodsThree adult female volunteers were selected as individuals with normal, vertical, and horizontal growth patterns. Frontal posed smile photographs were digitally altered by adjusting vertical positions of the maxillary canines above, below, or coincident with the incisal line in increments of 0.5 mm within a range of 1 mm of extrusion and intrusion. For assessment, a web-based survey was formed with 18 images (six images for each model). A scale was present underneath each image, graded from 0 to 10 (0: unattractive; 10: the most attractive). Images were rated by 233 participants (105 orthodontists; 128 laypeople).ResultsOrthodontists scored 0-mm images significantly as the highest in all groups. Laypeople scored significantly higher for −0.5 mm images regardless of facial type. The lowest scored images were −1 mm (except for horizontal pattern) and +1 mm images. Mean values of scores given by men were higher (P < .05).ConclusionsOrthodontists favored ideal dental alignment and preferred the incisal edges of central and canine teeth to be at the same level. Laypeople preferred a smoother smile arc than orthodontists and found harmony with the soft tissue more attractive. Facial type affected perceptions of the vertical changes of maxillary canines.     

牙科陶瓷材料疲劳性能的研究进展

牙科全瓷材料的临床应用日趋普及,但全瓷修复体在口腔环境内行使功能时常出现疲劳失效现象,导致使用寿命缩短并限制了其使用范围。因此,全瓷修复体的疲劳性能已经引起越来越多口腔临床工作者的关注。本文对牙科陶瓷材料的疲劳性能的研究方法及疲劳模式的研究现状和影响因素等方面进行综述。     

Standardized portrait photography for dental patients

Photography is becoming an increasingly important tool in the dental profession. But documentation of orthodontic or orthognathic treatment with pretreatment and posttreatment photographs can be misleading if features on one or both photographs are distorted. The dental photographer must be constantly aware of the importance of standardizing photographic variables when documentation of change is important. Although total reproducibility may not be practical, the photographer can establish a reasonably standardized approach to photographing patients. In this article the authors present the major considerations for frontal and profile facial photographs. Lens selection, camera position, subject distance, and position are all variables to be understood and controlled if accurate reproduction is desired. Numerous frontal and lateral photographs were made with head position, camera position, jaw position, and lens focal length changed to allow assessment of their contribution to the final picture. Using easily recognized facial landmarks, dental photographers can standardize frontal and lateral portraits for more consistent comparison.     

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.