Smile makeover and the oral facial harmony concept in a new era: relationship between tooth shape and face configuration

The patient's facial characteristics play an essential role in achieving a customized smile restoration with appropriate individualized tooth shapes. By initially studying the patient's face, an approach can be determined to plan new individual tooth shapes to achieve a satisfactory outcome. The dental esthetic rehabilitation taking the facial proportion into account involves a complex planning process. To successfully realize such a project, several factors must be evaluated when designing the restoration, including dental alignment, crown dimension, color, occlusion, and facial proportions. Understanding all the anatomical parameters is essential to creating a harmonious esthetic restoration. The facial type of a patient is not only defined by facial symmetry, asymmetry or anthropology but also by an awareness of things through the physical senses (perception); the way things seem, look or feel (impression); and the perceiver's personal interpretation of esthetic excellence and attractiveness (beauty). Other aspects of the face that can be defined for the purposes of the restoration project include strong, dynamic, delicate, and calm.1,2 Nowadays, many patients seek a more attractive appearance. There are several techniques available to perform esthetically pleasing restorations. Ongoing research is being conducted in this area, for instance, the concept known as oral facial harmony.3,4 Dentists have been conducting orofacial analyses for decades, a process that involves applying mathematical rules and geometry principles to create parallel or perpendicular lines on a patient's face. The aim is to achieve harmony rather than symmetry in the redefinition of the smile, because people's faces are naturally asymmetric. The idea, then, is to create a balanced harmonious smile in relation to the patient's face, which is more important than trying to create a mathematically perfect symmetrical smile.5.

[Dynamic esthetic analysis of the anterior teeth in normal occlusion in individuals aged 18-49 years]

Objective: To investigate the relationship between age, sex, length of upper lip and the exposure of maxillary central incisor. Methods: A total of 304 participants in normal occlusion (154 males, 150 females, aged 18-49 years) were recruited in this study from patients, visited the Medical Examination Center, Affiliated People's Hospital, Shanxi Medical University from January 2019 to August 2020. Participants were divided into 18-29 years old group (104, 53 males, 51 females), 30-39 years old group (110, 56 males, 54 females) and 40-49 years old group (90, 45 males, 45 females). Facial photography was used to record the facial state during the mandibular postural position, "che" pronunciation position and posed smile. The upper lip length, upper lip thickness and the exposure of maxillary central incisor were measured by ImageJ. The differences of measurement items in each group and the gender differences of each measurement item were analyzed. The length of upper lip and the exposure of upper central incisor in the mandibular postural position were analyzed by Pearson correlation. Results: In the mandibular postural position, the length of upper lip was (21.9±2.2), (22.5±2.5) and (23.1±2.2) mm in the 18-29 years old, 30-39 years old and 40-49 years old groups, and the length of upper lip in the 40-49 years old group was significantly larger than that in the 18-29 years old group (P<0.05). The exposure of upper central incisor in the 40-49 years old group during the mandibular postural position, "che" pronunciation position and posed smile [(1.4±1.2), (4.7±2.4), (7.7±2.4) mm, respectively] were significantly lower than those in the 18-29 years old group [(2.3±1.4), (5.5±2.2) and (8.8±2.0) mm] (P<0.05). The exposure of upper central incisor in the 30-39 years old group during the mandibular postural position and posed smile [(1.8±1.4), (8.2±2.0) mm, respectively] was significantly lower than those in the 18-29 years old group (P<0.05). With the increase of age, the exposure of upper central incisor decreased gradually. In the same group, the exposure of upper central incisor in the female during the mandibular postural position and "che" pronunciation position (except 40 to 49 years old group) were significantly larger than those in the male (P<0.05), and there was no statistically significant difference between the sexes in the posed smile (P>0.05). There was a significant linear correlation between the exposure of upper central incisor and the length of upper lip at the mandibular postural position in normal occlusion aged 18-49 (r=-0.325, P<0.01). Conclusions: Gender factor should be considered in the esthetic design of anterior teeth. The exposure of anterior teeth in the mandibular postural position and "che" pronunciation position is more valuable than that in the posed smile. The length of upper lip in normal occlusion aged 40-49 was significantly shorter than that aged 18-29, and the exposure of upper central incisors was significantly reduced.

Holistic reconstruction of mandible defect, lower lip and chin sensation, and smile reanimation in an advanced gum cancer patient: A case report

Facial deformity, facial paralysis, and sensory loss are inevitable after some head and neck tumor resection and reconstruction, especially in high stage cancer. To overcome these obstacles, we present a case of T4a gum cancer patient (41-year-old) who received holistic reconstruction of the mandible defect via an osteo-peroneal-artery-perforator combined flap for defect coverage and cross-mental nerve graft for lower lip and chin sensation at the primary stage, followed by ipsilateral facial nerve (lower trunk) innervated gracilis functioning free muscle transplantation for facial reanimation and correction of the sunken face 3 years later. After 4.5 years of follow-up, the patient was satisfied with his appearance, and obtained a spontaneous and symmetrical smile without sensory deficit. This experience showed a possible solution to the reconstruction for complicated head and neck cancer patients.

Evaluating the Impacts of Some Etiologically Relevant Factors on Excessive Gingival Display

The literature offers limited and even conflicting information on the etiology of gummy smile. Therefore, this study aimed to evaluate smile line, hypermobile upper lip (HUL), altered passive eruption (APE), and short upper lip (SUL) distribution in a group of patients seeking dental treatment and examine their effects on gummy smile. A total of 501 individuals (265 men, 236 women) were included in the study. The patients were grouped by gingival display, and presence of HUL, APE, and SUL were evaluated. Multivariate Logistic Regression analyses were performed to investigate the impact of possible risk factors on gummy smile. Of the individuals, 173 (34.5%) had a low smile line, 127 (25.3%) had an average smile line, 146 (29.1%) had a high smile line, and 55 (10.9%) were gummy smile patients. Individuals with gummy smile were younger than the individuals with low smile line (P < .001). As for the possible risk factors for gummy smile, age (odds ratio [OR]: 0.936; 95% CI: 0.901 to 0.972; P = .001), HUL (OR: 18.85; 95% CI: 7.82 to 45.44; P < .001), and APE (OR: 8.819; 95% CI: 3.894 to 19.973; P < .001) were found to be significant together. Gender and SUL/upper lip length were not found to have any impact on gummy smile. HUL is the primary factor that increases the probability of having gummy smile, followed by APE as the secondary factor. It seems reasonable to focus on correction of the HUL for treatment in most gummy smile patients.

Oral competence following facial nerve paralysis: Functional and quality of life measures

PURPOSE

Oral competence refers to the maintenance of lip closure with sufficient strength to prevent anterior spillage of saliva, food and fluid, and to clearly articulate labial sounds. Despite facial nerve paralysis having an impact on eating, drinking and communicating, little research has been done in this area.

METHOD

Studies examining oral competence associated with a diagnosis of facial nerve paralysis were considered using Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement checklists and evaluated for their risk of bias using the RevMan Risk of Bias Tool.

RESULT

44 articles were examined. There was an over-representation of case-series and cohort studies. All studies carried a high risk of bias due to lack of (a) validated outcome measures, (b) comparison group and (c) blinding or randomised assessors and participants. Studies primarily examined facial nerve intervention for the purpose of restoring smiling or facial aesthetics rather than oral competence.

CONCLUSION

Whilst oral competence is often compromised after a facial nerve paralysis, it is inconsistently measured, managed and described. Further studies are required to examine the (a) incidence, (b) severity and (c) impact on quality of life relating to oral incompetence using validated measures at consistent time intervals.

Evaluation of Maxillary Anterior Teeth Width and Their Relation to the Calculated Values for Smile Designing

AIM AND OBJECTIVE

The present study was conducted to determine the golden proportion, golden mean, and the Preston proportion of the individuals between the widths of six maxillary anterior teeth and to determine which proportional formula exists in the population.

MATERIALS AND METHODS

This study was conducted among 60 participants between 18 years and 30 years of age with an esthetic smile. They were grouped into 30 females and 30 males. Maxillary arch impressions were made using irreversible hydrocolloid material from each individual. The width of the anterior teeth on the graph paper was analyzed by using digital vernier caliper. The data were statistically analyzed by one way ANOVA test.

RESULTS

The study revealed that the formula of golden proportion and golden mean had no statistical differences between males and females but the Preston proportion has shown statistical differences in the total population.

CONCLUSION

From the current study, it was concluded that the formulas of golden mean and golden proportion proposed by Ward can be used for smile designing and full mouth rehabilitations.

CLINICAL SIGNIFICANCE

Demand for smiles has gained its importance with time. The golden proportion, golden mean, and the Preston proportion are the guidelines used by the professional for better esthetic proportion in the dentition.

Long-term outcomes of dual innervation in functional muscle transfers for facial palsy

BACKGROUND

This study describes a different approach with a 2-stage facial reanimation in patients with long-standing unilateral facial paralysis using free gracilis muscle transfer, innervated by both cross-facial nerve graft and masseteric nerve. The authors present their rationale, surgical technique, and long-term outcomes.

METHODS

Between August 2012 and March 2016, 11 patients (6 female and 5 male patients) underwent a 2-staged dually innervated gracilis muscle transfer. Patients were evaluated with physical examination and needle electromyography. A standardized assessment of preoperative and postoperative photographs and videos was performed using Terzis' smile functional grading system at 48 months following surgery and the Emotrics software to assess improvement in symmetry over a 36-month postoperative period.

RESULTS

Voluntary contraction of the gracilis muscle was observed in all patients at a mean of 4 months and 4 days following muscle transfer. A spontaneous smile produced without teeth clenching was developed in all patients by 18 months postoperatively. Six patients achieved excellent and 5 good results. The difference between the averaged pre- and postoperative scores was statistically significant. With Emotrics, there were significant improvements in the smile angle, upper lip elevation, commissural excursion, and commissural height, with continuous improvement over 36 months. The postoperative electromyography (EMG) confirmed dual innervation of the gracilis muscle by the facial and masseteric donor motor neural sources. We present our results at minimum 48 months postoperatively.

CONCLUSIONS

Dual innervated two-stage gracilis transfer is an effective method for reanimation in long-standing unilateral facial paralysis, providing both rapid reinnervation of the transferred muscle, together with a powerful, synchronous smile.

Lip repositioning surgery for gummy smile: 6-month clinical and radiographic lip dimensional changes

OBJECTIVES

The present case series aimed to examine lip repositioning surgery (LRS) outcomes related to changes in external and internal upper lip (UL) dimensions, utilizing both conventional clinical and novel radiographic approaches.

MATERIALS AND METHODS

Patients (n = 13) diagnosed with hypermobile UL (>8-mm mobility during smile) and excessive gingival display (≥4-mm) were included and assessed at baseline and 6 months postoperatively. Clinical parameters at rest included total lip and internal lip length (vestibular depth). At maximum smile included total lip, philtrum (ergotrid), and vermilion lengths. Cephalometric parameters included anterior maxillary height; lip length; nasolabial angle; anteroposterior lip thickness; internal lip length (vestibular depth); and vestibular fornix position (using novel approach employing radiopaque marker). Linear mixed-effect models, Pearson's correlation, and linear regression were used for statistical analyses.

RESULTS

LRS did not affect total UL length at rest (p = 0.418). It resulted in significant internal UL length decrease (-3.8 ± 2.1 mm, p < 0.001) and significant increases of vermilion length (1.9 ± 1.0 mm, p < 0.001) and anteroposterior lip thickness (0.7 ± 0.7 mm, p = 0.002). The clinical and radiographic measurements of total UL length at rest (r ≥ 0.734) and of internal UL length (r ≥ 0.737), and the two radiographic assessments of vestibular depth (r = 0.842), were strongly correlated.

CONCLUSIONS

LRS resulted in significant decrease of vestibular depth/internal UL length and in significant increases of UL vertical vermilion length and UL anteroposterior thickness, without affecting total UL length at rest.

CLINICAL RELEVANCE

The documented lip dimensional outcomes should help practitioners when treatment-planning LRS and counseling patients seeking treatment for hypermobile UL.

Management of gummy smile using botulinum toxin: a case series

A "gummy smile," considered to be exposure of more than 3.0 mm of gingival tissue during a forced smile, negatively affects smile esthetics. The present case series describes the clinical indications and technique for applying botulinum neurotoxin type A (BoNTA) to correct a gummy smile and assesses the outcomes and satisfaction levels of 3 patients. The patients were told about the risks and benefits of the procedure and advised that their gummy smile was likely to recur within 6 months posttreatment. After the exposed gingival tissue of the patients was measured with a ruler, photographs were taken, and the patients recorded their pretreatment level of satisfaction with their smile on a visual analog scale (VAS), the patients were treated with BoNTA. The BoNTA was diluted in 1 mL of sterile saline according to the manufacturer's instructions, and an extraoral point of application was marked 1 mm lateral to each of the patient's nasal wings, close to the insertion of the elevator muscles of the upper lip and the nasal wings. At each location, 4 U was injected by tilting the syringe 45° in relation to the skin. Fourteen days after treatment, the gingival tissue exposed during a smile was again measured with a ruler, new photographic records were taken, and the patients' level of satisfaction with the treatment and the esthetic result was determined. Repositioning of the upper lip was observed in all patients. No adverse effects or complaints were reported. All 3 patients reported that they were satisfied with the outcome and wanted to continue therapy with BoNTA as needed. The results of the reported cases suggest that the application of BoNTA constitutes a safe, effective treatment for the correction of gummy smile and is well accepted by patients. However, for the treatment to be successful, it is essential that clinicians master the facial topographic anatomy and the technique to be employed.

The Smiles of Older People through Recreational Activities: Relationship between Smiles and Joy

Recreational activities are found to increase people's smiles, arising joy in older people, but there is limited research on this topic within the Japanese context. This cross-sectional study aimed to measure the quality and frequency of smiles in older people living in rural settings using a smile analysis application. The participants comprised 13 females aged over 65 years who lived in Unnan City, Japan, and regularly attended recreational meetings. In this study, the recreational activity that the participants joined was a game called Mattoss. A video camera captured the participants' faces, while a smile assessment application assessed their facial expressions for smiles and joy. A total of 2767 smiles were recorded. For validity, we calculated the Spearman's rho score between smile and joy, which was 0.9697 (p < 0.001), while for reliability, we determined the Spearman's rho score for each participant, which exceeded 0.7 (p < 0.001). Surges of smiles were induced by one's own mistakes, successes, and big mistakes in the game and by severe or mild judgments by the referee. High validity and reliability of smile evaluation were demonstrated. The study found that smiling increased during recreational activities. Therefore, recreational activities can be encouraged for older people living in rural communities.

Determination of Facial References for Esthetic Restorative Treatment

Although it is generally accepted that a prosthetic restoration must take into account the gingiva, smile, and patient's face, it is often difficult to determine precisely what facial references must be considered. The purpose of this study was to determine the correct vertical and horizontal facial reference planes in esthetic prosthetic treatment. Using photographic analysis of 160 individuals, the different facial reference planes (interpupillary, intermeatic, intercommissural, and incisal edge lines; facial midline; and Camper and Frankfort planes) were compared to the ideal prosthetic reconstruction axis. Additional measurements, including the human eye's ability to perceive parallelism, were recorded. Most participants (64%) exhibited facial asymmetry. Asymmetry was horizontal (difference between widths of the right and left sides; 52.4%), vertical (difference between heights of the right and left sides; 6.9%), or mixed (4.7%). The interpupillary line is the main horizontal reference in 88.4% of situations, with the intercommissural line the second most important. In the profile view, the horizontal plane was on average 6.5 degrees above the Camper plane and 9 degrees below the Frankfort plane. The human eye's ability to perceive parallelism between two lines was found to be limited to differences of approximately 1 degree. During anterior tooth reconstruction, it is necessary to take into account the right horizontal and vertical esthetic references. Knowledge of the biometric facial parameters in natural dentition is necessary to define the right reconstruction axes based on the facial symmetry or asymmetry.

Dynamics of facial actions for assessing smile genuineness

Applying computer vision techniques to distinguish between spontaneous and posed smiles is an active research topic of affective computing. Although there have been many works published addressing this problem and a couple of excellent benchmark databases created, the existing state-of-the-art approaches do not exploit the action units defined within the Facial Action Coding System that has become a standard in facial expression analysis. In this work, we explore the possibilities of extracting discriminative features directly from the dynamics of facial action units to differentiate between genuine and posed smiles. We report the results of our experimental study which shows that the proposed features offer competitive performance to those based on facial landmark analysis and on textural descriptors extracted from spatial-temporal blocks. We make these features publicly available for the UvA-NEMO and BBC databases, which will allow other researchers to further improve the classification scores, while preserving the interpretation capabilities attributed to the use of facial action units. Moreover, we have developed a new technique for identifying the smile phases, which is robust against the noise and allows for continuous analysis of facial videos.

The fifth dimension in esthetic dentistry

Every human smile is unique and special, reflecting the different shapes, textures, and colors of the teeth as well as their combinations. This uniqueness conveys a direct and specific message when it comes to creating a new smile design. Dentists need to consider the 'unity of the whole' concept in this task, which involves bringing together biology, structure, function, and esthetics to create the fifth dimension of the smile. This approach is quite different from the traditional one. A smile reflects the personality and emotional state of the patient, and the translation of this into a new smile design occurs in various ways. This can be performed either through analog methods or digitally; however, the use of visual language will assist the dentist and dental technician in the creation of a personalized smile design. Nowadays, with the significant digital advances that have occurred in dentistry, there are systems on the market that help the dental team to create a personalized new smile design for each specific patient. The Rebel system is one example of such a system. It is actually a virtual laboratory that creates individualized smile designs in three dimensions. The system, with its very sophisticated artificial intelligence (AI)-based software, immediately creates a digital wax-up (STL file). It is therefore simple to use for dentists and dental technicians at all skill levels because the direct mock-up and wax-up stages are eliminated.

Does the presence of maxillary midline diastema influence the perception of dentofacial esthetics in video analysis?

OBJECTIVE

To evaluate the influence of a midline diastema on dentofacial esthetic perceptions of orthodontists, restorative dental specialists or prosthodontists, and laypersons in a frontal facial evaluation performed by means of video.

MATERIALS AND METHODS

Two individuals aged between 20 and 25 years, one of each gender, with presence of a midline diastema were selected. An acrylic resin mockup was made of the maxillary anterior region, simulating ideal conditions of smile esthetics. Four standardized frontal view videos of the complete face were filmed of each individual in the following situations: with the ideal smile (unchanged mockup) and with the presence of midline diastemas of 0.5, 1.0, and 1.5 mm created by the mockup. In all videos, the patient said a certain sentence and, at the end, simulated a posed smile. Dentofacial esthetic perceptions of all four videos of each individual were evaluated by 51 orthodontists, 51 restorative dental specialists or prosthodontists, and 51 laypersons by means of visual analog scales. Data were evaluated using analysis of variance and Tukey post hoc test, with the level of significance set at 5%.

RESULTS

The most attractive videos for all groups of examiners were those without diastema and with a diastema of 0.5 mm, for both the woman and the man. For a diastema of 1 mm or 1.5 mm, the dentofacial characteristics were considered unesthetic.

CONCLUSIONS

Diastemas equal to or greater than 1 mm negatively influence dentofacial esthetics in a frontal facial evaluation performed by means of video.

Workflow of digitally guided direct composite resin restorations using ?open source software and 3D printing: a clinical technique

<p>Objective: To describe how to perform, in a simple manner, a digital wax-up with ?open source software for a clinical application involving direct ?composit?e resin restorations. Report: The clinical technique described presents a simple and highly predictable way of performing direct restorations with the help of a digital wax-up made with ?open source software. ?It uses an open source digital tooth library? to reestablish a more harmonious smile architecture, specifically of teeth that were worn due to parafunction, and restored with direct composite resin restorations.<br /> Conclusions: Thanks to the technology that was used in this case, fast, affordable and accurate results c?ould be obtained. In addition, digital files can be stored, saving material, time, and space, and allowing identical replication of the work either virtually or printed at any time, if needed. (Quintessence Int 2021;52:104-110; doi:&nbsp;10.3290/j.qi.a45426)</p>.

The effect of botox for the correction of the gummy smile: A systematic review

PURPOSE

The aim of the systematic review was to analyze the effectiveness of Botox injections for the treatment of the gummy smile.

MATERIALS AND METHODS

The systematic literature search was done in the databases: PubMed, Embase and Cochrane Library. The articles published from 2013 to 2020 were searched. Only studies on humans were included in this systematic literature review.

RESULTS

During the initial search a total number of 139 articles were detected. However, after the removal of duplications 105 articles were left. Regarding the application of inclusion and exclusion criteria, 6 articles were selected for this systematic literature review.

CONCLUSIONS

The results of this study suggested that botulinum toxin was an efficient method to treat the gummy smile.

[Evaluation of the reproducibility of non-verbal facial expressions in normal persons using dynamic stereophotogrammetric system]

OBJECTIVE

To assess the reproducibility of non-verbal facial expressions (smile lips closed, smile lips open, lip purse, cheek puff) in normal persons using dynamic three-dimensional (3D) imaging and provide reference data for future research.

METHODS

In this study, 15 adults (7 males and 8 females) without facial asymmetry and facial nerve dysfunction were recruited. Each participant was seated upright in front of the 3D imaging system in natural head position. The whole face could be captured in all six cameras. The dynamic 3D system captured 60 3D images per second. Four facial expressions were included: smile lips closed, smile lips open, lip purse, and cheek puff. Before starting, we instructed the subjects to make facial expressions to develop muscle memory. During recording, each facial expression took about 3 to 4 seconds. At least 1 week later, the procedure was repeated. The rest position (T0) was considered as the base frame. The first quartile of expressions (T1), just after reaching the maximum state of expressions (T2), just before the end of maximum state of expressions (T3), the third quartile of expressions (T4), and the end of motion (T5) were selected as key frames. Using the stable part of face such as forehead, each key frame (T1-T5) of the different expressions was aligned on the corresponding frame at rest (T0). The root mean square (RMS) between each key frame and its corresponding frame at rest were calculated. The Wilcoxon signed ranks test was applied to assess statistical differences between the corresponding frames of the different facial expressions.

RESULTS

Facial expressions like smile lips closed, smile lips open, and cheek puff were reproducible. Lip purse was not reproducible. The statistically significant differences were found on the T2 frame of the repeated lip purse movement.

CONCLUSION

The dynamic 3D imaging can be used to evaluate the reproducibility of facial expressions. Compared with the qualitative analysis and two-dimensions analysis, dynamic 3D images can be able to more truly represent the facial expressions which make the research more reliable.

Siamese Architecture-Based 3D DenseNet with Person-Specific Normalization Using Neutral Expression for Spontaneous and Posed Smile Classification

Clinical studies have demonstrated that spontaneous and posed smiles have spatiotemporal differences in facial muscle movements, such as laterally asymmetric movements, which use different facial muscles. In this study, a model was developed in which video classification of the two types of smile was performed using a 3D convolutional neural network (CNN) applying a Siamese network, and using a neutral expression as reference input. The proposed model makes the following contributions. First, the developed model solves the problem caused by the differences in appearance between individuals, because it learns the spatiotemporal differences between the neutral expression of an individual and spontaneous and posed smiles. Second, using a neutral expression as an anchor improves the model accuracy, when compared to that of the conventional method using genuine and imposter pairs. Third, by using a neutral expression as an anchor image, it is possible to develop a fully automated classification system for spontaneous and posed smiles. In addition, visualizations were designed for the Siamese architecture-based 3D CNN to analyze the accuracy improvement, and to compare the proposed and conventional methods through feature analysis, using principal component analysis (PCA).

Do I trust you when you smile? Effects of sex and emotional expression on facial trustworthiness appraisal

Background

Trust is a prerequisite for successful social relations. People tend to form a first impression of people‘s trustworthiness based on their facial appearance. The sex of the judging person and its congruency with the sex of the judged people influence these appraisals. Moreover, trustworthiness and happiness share some facial features, which has led to studies investigating the interplay between both social judgments. Studies revealed high correlation in judging happiness and trustworthiness across different facial identities. However, studies are missing that investigate whether this relationship exists on a within-subject level and whether in-group biases such as the congruency between the sex of the judging and judged individual influence this relationship. In the present study, we addressed these questions.

Methods

Data were collected in an online-survey in two separate samples (N = 30, German sample, N = 107 Dutch sample). Subjects assessed the intensity of happiness and trustworthiness expressed in neutral and calm facial expression of the same characters (50% males, 50% females). Statistical analyses comprised rm-Anova designs based on rating scores and estimates of within-subject associations between both judgments.

Results

Our findings replicate high correlations between happiness and trustworthiness ratings across facial identities based on average scores across participants. However, the strength of this association was strongly dependent on the methodological approach and inter-subject variability was high. Our data revealed an in-group advantage for trustworthiness in women. Moreover, the faces’ sex and emotional expressions differentially influenced the within-subject correlation between both judgments in men and women.

Conclusion

Our findings replicate previous studies on the association between happiness and trustworthiness judgments. We extend our understanding of the link between both social judgments by uncovering that within-subject variability is high and influenced by sex and the availability and appraisal of positive emotional facial cues.

[Influence of canine vertical position on smile esthetic perceptions by using 3D digital facial reconstruction]

PURPOSE

To verify the impact of alterations in the vertical position of maxillary canine on smile esthetic perceptions, in order to find an optimal canine position.

METHODS

A volunteer's dentition and facial images were scanned by intra-oral scanning and three-dimensional facial scanning, which were then calibrated. In virtue of dental computer-aided design software, the canine vertical positions were symmetrically modified in a variable of 0.5 mm, creating 4 new 3D virtual digital smile faces varying from 1.0 mm of intrusion to 1.0 mm of extrusion. A total of 5 3D virtual digital smile faces were evaluated from the front and 45°to the right sides by 60 dentists and 60 laypersons on a visual analog scale. The data were input into SPSS 20.0 software package, ANOVA of repeated measurement was used to compare the differences in the assessment scores between two groups and rank sum test was used to analyze the differences from different evaluation angles.

RESULTS

Alterations in the vertical position of maxillary canine had significant influence on the esthetic evaluation of the smile(P<0.05); there was significant difference between the dentists' and laypersons' esthetic evaluations after the canine vertical position being modified(P<0.05), there was no significant difference on the evaluations of smile esthetics from different evaluation perspectives(P>0.05).

CONCLUSIONS

The most attractive smile was the one with canine cusp 0.5 mm vertically higher than the incisal edge of the lateral incisor. The smile is not attractive when the cusp of canine is vertically lower than the incisal edge of lateral incisor. These results can be used as references in the esthetic treatment planning for anterior maxillary teeth.

"Smile pretty and watch your back: Personal safety anxiety and vigilance in objectification theory." Correction to Calogero et al. (2020)

Reports an error in "Smile pretty and watch your back: Personal safety anxiety and vigilance in objectification theory" by Rachel M. Calogero, Tracy L. Tylka, Jaclyn A. Siegel, Afroditi Pina and Tomi-Ann Roberts (Journal of Personality and Social Psychology, Advanced Online Publication, Sep 17, 2020, np). In Table 4, the mean, standard deviation, and range for the Personal Safety Anxiety and Vigilance (PSAVS) variable were incorrect. (The following abstract of the original article appeared in record 2020-69774-001.) Objectification Theory posits that everyday encounters with sexual objectification carry a diffuse nonspecific sense of threat that engenders personal safety anxiety in women. In this article, we provide direct evidence for this tenet across 5 studies and 1,665 participants using multiple methods. Study 1 (N = 207) and Study 2 (N = 161) explored and confirmed the factor structure of the Personal Safety Anxiety and Vigilance Scale (PSAVS), a measure of personal safety anxiety, and provided evidence for the reliability and construct validity of its scores. Study 3 (N = 363) showed that personal safety anxiety is a conceptually different construct for women and men, and differentially mediated the relation between sexual objectification and restricted freedom of movement and the relation between self-objectification and restricted freedom of movement for women and men. Study 4 (N = 460) included a comprehensive test of personal safety anxiety within an expanded Objectification Theory model, which supported personal safety anxiety as a mediator of the links from sexual and self-objectification to women's restricted freedom of movement. Study 5 (N = 474) replicated these results while also adjusting for specific fears of crime and rape. Our findings offer a newly validated assessment tool for future research on safety anxiety, illuminate the real and lasting sense of threat engendered by everyday sexual objectification, and broaden understanding of the mental and physical constraints on women's lived experiences posited in Objectification Theory. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Long-term results of facial animation surgery in patients with Moebius syndrome

Gracilis neuromuscular transplant is considered the gold standard for facial animation in Moebius syndrome patients. However, long-term evaluation of the results has not been critically examined in the international literature. Thus, it remains unknown how the transplanted flap changes with facial growth, and whether contraction (smiling) is maintained. Pediatric patients with Moebius syndrome who underwent facial animation surgery with at least 5 years of follow-up were retrospectively examined. Photographs taken at the 1-year and most recent follow-up visits were analyzed and compared using Emotrics software. Analyses focused on the rest position, and on gentle and maximum smiles. Eighteen patients were enrolled. Seven patients had bilateral and 11 unilateral Moebius syndrome; therefore, 25 gracilis transplants were analyzed. The latest follow-ups ranged from 5 to 13.2 years (mean 7.6 years). The three principal facial expressions that were examined did not differ significantly between 1 year and a mean of 7.6 years after surgery, but tended to improve in most patients. Commissure excursion and smile angle for the maximum smile did improve significantly (p = 0.002 and 0.029, respectively). The series examined in this study supports the limited literature regarding the long-term stability of gracilis transplantation to animate the faces of Moebius syndrome children.

Predictability in Lip Repositioning with Botulinum Toxin for Gummy Smile Treatment: A 3-Year Follow-up Case Series

The aim of this case series was to describe the successful treatment of excessive gingival display (EGD) using a lip repositioning technique (LRT) and botulinum toxin injections (BTIs) for long-term stability. Eight patients diagnosed with EGD were enrolled. A partial-thickness horizontal incision was made from the right first molar to the left first molar along the mucogingival line, leaving the midline frenum intact. The next day, all patients received BTIs. Mean reductions in gingival display between baseline and 3, 6, 12, 18, 24, and 36 months after surgery were considered. BTIs prevent movement of the upper lip during the healing phase of the LRT, improving the results and offering long-term outcomes with a follow-up period of 3 years.

Dimensions of Maxillary Lateral Incisor on the Esthetic Perception of Smile: A Comparative Study of Dental Professionals and the General Population

AIM

To evaluate the effect of the differences in the dimensions of maxillary lateral incisor on the esthetic perception of smile among dental professionals and the general population.

MATERIALS AND METHODS

Two sets of photographs where the maxillary incisor dimensions were modified using computer software (Adobe Photoshop) were created. In the first set, six images were included where the maxillary lateral incisor width was modified. The second set included five images where only the maxillary lateral incisor length was modified keeping the gingival margins same. Three groups of participants formed the sample. Hypodontia patients formed the first group, non-hypodontia patients formed the control group, while the dentists constituted to the third group. A total of 156 participants were recruited, 36 patients with radiographically confirmed hypodontia out of which 22 were female and 14 were male, 54 non-hypodontia "control" patients out of which 29 were female and 24 were male, and 66 dentists out of which 39 were female and 27 were male. Every participant had 15 seconds to view each photograph along with 30 seconds at the end for confirmation.

RESULTS

The "most attractive smile" was the ones with 77% lateral incisor to central incisor width proportion according to 25.0% of the hypodontia group and 40.8% of the dentist's group, while only 4.2% of the control group agreed that it was the most attractive. However, the "least popular" was the 52% lateral incisor to central incisor width proportion according to 40.0% of patients who are hypodontic, 20.8% of participants from control group, and 49.0% of dentists.

CONCLUSION

The golden proportion was not considered as the most attractive among all groups. The esthetic perceptions of the patients might not be same as that of the dentists. In general, reductions in the maxillary lateral incisor width were not all acceptable.

CLINICAL SIGNIFICANCE

This study will help us understand the different perceptions of the patients and the dentists on esthetics, which would further help us in planning the treatment accordingly.

Botulinum Toxin Type-A for the Treatment of Excessive Gingival Display on Smiling

AIM AND OBJECTIVE

To determine the effect of botulinum toxin type-A (BTX-A) in reducing gummy smile.

MATERIALS AND METHODS

This was an interventional case series conducted at a tertiary care setting in Mangaluru, Karnataka, India. Twenty patients with the gingival display of >3 mm were selected through convenience sampling technique. 2.5 units of BTX-A were injected under sterile conditions on either side of the face. The effect of the injection on gingival display was measured at the interval of 2, 4, 12, and 24 weeks. At the end of the treatment, the patient was asked to smile and was photographed and was compared to pretreatment photo. Repeated measures analysis of variance (ANOVA) was used to detect the change at each interval and intergroup comparisons were performed using post hoc Bonferroni test.

RESULTS

The mean gingival exposure reduction from 4.93 to 3.705 mm at week 2. At the end of 24 weeks, the evaluation showed the mean gingival display of 4.755 mm on administration of 2.5 units on either side. The photographs also showed the change in smile at the end of the treatment.

CONCLUSION

From the study, it was inferred that botulinum toxin was effective in eliminating gummy smile along with noticeable decrease in the nasolabial fold despite for the effect lasting only about 24 weeks.

CLINICAL SIGNIFICANCE

A nonsurgical method of correction of gummy smiles when compared to surgical intervention is readily accepted by patients. Botulinum toxin type-A for gummy smiles is an effective, conservative, and satisfactory technique.

[FACIAL NERVE PARALYSIS - THERAPEUTIC APPROACH, FACIAL REANIMATION AND ADJUNCTIVE TREATMENT]

Paralysis of the facial mimetic muscles causes loss of voluntary and non-voluntary muscle function, as well as facial tone. This is a devastating condition with profound functional, aesthetic and psychological consequences. Etiologies include congenital paralysis and acquired paralysis following viral infection, trauma, head and neck tumors, iatrogenic damage and more. Clinical presentation includes ocular symptoms (dry eye, epiphora, corneal irritation), nasal symptoms (nasal obstruction) and oral symptoms (drooling and speech disturbances). Reconstruction of facial nerve function is based on renewing the neural input to the paralyzed face in parallel with transferring a functioning muscle. The gold standard in long term facial paralysis reanimation includes a two-stage procedure that involves cross-face nerve grafting and later on a free gracilis muscle transfer. This method allows reconstruction of a symmetric, spontaneous and voluntary smile. In cases when cross-face nerve grafting is impossible, a free-gracilis muscle transfer is performed with neural coaptation to another cranial nerve, most commonly the motor nerve to the masseter muscle (of the trigeminal nerve). Non-microsurgical methods for facial reanimation exist, however, nowadays they are rarely performed. In addition to the surgical reconstruction, other surgical and non-surgical procedures are performed for functional and aesthetic symmetrization purposes. These include fat injection to the face, botulinum toxin injection, oculoplastic procedures and more. In this article we describe our patient population with facial nerve paralysis, common facial reanimation procedures, considerations in choosing the appropriate reconstruction procedure and the general approach for treatment of facial paralysis in our multidisciplinary facial paralysis clinic.

Classification of facial movements in chronic facial palsy based on intramuscular EMG signals recorded from the paretic side

Patients suffering from chronic facial palsy are frequently impaired by severe life-long dysfunctions. Thus, the loss of the ability to close eyes rapidly and completely bears the risk of corneal damages. Moreover, the loss of smile and an altered facial expression imply psychological stress and impede a healthy social life. Since surgical and conservative treatments frequently do not solve many problems sufficiently, closed-loop neural prosthesis are considered as feasible approach. For it, amongst others a reliable detection of the currently executed facial movement is necessary. In our proof of concept study, we propose a data-driven feature extraction for classifying eye closures and smile based on intramuscular EMGs from orbicularis oculi and zygomaticus muscles of the patient's palsy side. The data-adaptive nature of the approach enables a flexible applicability to different muscles and subjects without patient-or muscle-specific adaptations.

The step further smile virtual planning: milled versus prototyped mock-ups for the evaluation of the designed smile characteristics

BACKGROUND

Mock-up based approach allows the preview of the aesthetic rehabilitation, however, it is crucial that the mock-up does not differ from the expected aesthetic outcomes. With CAD-CAM technologies, it is possible to directly create mock-ups from virtual planned smile project, with greater accuracy and efficiency compared to the conventional moulded mock-ups. In this study, we investigated the trueness of mock-ups obtained with milling and 3D printing technology and a full digital work-flow system.

METHODS

Ten adults subjects were included and digital smile design/digital wax-up were performed to enhance the aesthetic of maxillary anterior region. Ten milled mock-ups and 10 prototyped mock-ups were obtained from the original .stl file and a digital analysis of trueness was carried out by superimposing the scanned-milled mock-ups and the scanned-prototyped mock-ups to the digital wax-up, according to the surface-to-surface matching technique. Specific linear measurements were performed to investigate and compare the dimensional characteristics of the physical manufactures, the 3D project and the scanned mock-ups. All data were statistically analyzed. A clinical test was also performed to assess the fitting of the final manufacture.

RESULTS

The prototyped mock-ups showed a significant increment of the transversal measurements (p < 0.001) while the milled mock-ups showed a significant increment of all vertical and transversal measurements (p < 0.001). The prototyped mock-ups showed good fitting after clinical tests while none of the milled mock-ups showed good adaptation (no fitting or significant clinical compensation required). Deviation analysis from the original 3D project reported a greater matching percentage for the scanned-milled mock-ups (80,31% ± 2.50) compared to the scanned-prototyped mock-ups (69,17% ± 2.64) (p < 0.001). This was in contrast with the findings from linear measurements as well as from the clinical test and may have been affected by a reductive algorithmic computation after digitization of physical mock-ups.

CONCLUSION

Both prototype and milled mock-ups showed a slight dimensional increment comparing to the original 3D project, with milled-mock-ups showing less fitting after clinical tests. Caution must be taken when assessing the trueness of scanned manufacture since an intrinsic error in the system can underestimate the dimensions of the real object.

Imitation recognition and its prosocial effects in 6-month old infants

The experience of being imitated is theorised to be a driving force of infant social cognition, yet evidence on the emergence of imitation recognition and the effects of imitation in early infancy is disproportionately scarce. To address this lack of empirical evidence, in a within-subjects study we compared the responses of 6-month old infants when exposed to ipsilateral imitation as opposed to non-imitative contingent responding. To examine mediating mechanisms of imitation recognition, infants were also exposed to contralateral imitation and bodily imitation with suppressed emotional mimicry. We found that testing behaviours-the hallmark of high-level imitation recognition-occurred at significantly higher rates in each of the imitation conditions compared to the contingent responding condition. Moreover, when being imitated, infants showed higher levels of attention, smiling and approach behaviours compared to the contingent responding condition. The suppression of emotional mimicry moderated these results, leading to a decrease in all social responsiveness measures. The results show that imitation engenders prosocial effects in 6-month old infants and that infants at this age reliably show evidence of implicit and high-level imitation recognition. In turn, the latter can be indicative of infants' sensitivity to others' intentions directed toward them.

Large EEG amplitude effects are highly similar across Necker cube, smiley, and abstract stimuli

The information available through our senses is noisy, incomplete, and ambiguous. Our perceptual systems have to resolve this ambiguity to construct stable and reliable percepts. Previous EEG studies found large amplitude differences in two event-related potential (ERP) components 200 and 400 ms after stimulus onset when comparing ambiguous with disambiguated visual information ("ERP Ambiguity Effects"). These effects so far generalized across classical ambiguous figures from different visual categories at lower (geometry, motion) and intermediate (Gestalt perception) levels. The present study aimed to examine whether these ERP Effects are restricted to ambiguous figures or whether they also occur for different degrees of visibility. Smiley faces with low and high visibility of emotional expressions, as well as abstract figures with low and high visibility of a target curvature were presented. We thus compared ambiguity effects in geometric cube stimuli with visibility in emotional faces, and with visibility in abstract figures. ERP Effects were replicated for the geometric stimuli and very similar ERP Effects were found for stimuli with emotional face expressions but also for abstract figures. Conclusively, the ERP amplitude effects generalize across fundamentally different stimulus categories and show highly similar effects for different degrees of stimulus ambiguity and stimulus visibility. We postulate the existence of a high-level/meta-perceptual evaluation instance, beyond sensory details, that estimates the certainty of a perceptual decision. The ERP Effects may reflect differences in evaluation results.

Mobile dental photography: a simple technique for documentation and communication

Digital photography has already established its irrefutable importance in today's world. It is becoming an indispensable tool in various fields. In dentistry specifically, photography can be employed in several ways that can be beneficial to the patient and the dental community. It allows a simple and clear depiction of an otherwise abstract concept, but high-quality pictures are always required. The evolution of mobile cameras has made an enormous impact on digital photography and its accessibility: high-quality pictures can now be easily taken. This article explains the assets of smartphone cameras' evolution and how it led to the conception of Smile Lite Mobile Dental Photography. Applications of dental photography are presented, such as documentation and communication with the laboratory technician and the patient. Mobile dental photography is not confined to dentistry but can also be used for artistic purposes. (Quintessence Int 2020;51:510-518; doi: 10.3290/j.qi.a44365; Originally published (in German) in Quintessenz Zahnmedizin 2019(12);70:1408-1417).

Smile attractiveness of Persian women after orthodontic treatment

INTRODUCTION

Achieving a balanced, attractive smile is an important goal in contemporary orthodontics. This study aimed to assess the smile attractiveness of Persian women after orthodontic treatment.

METHODS

In this descriptive-analytical study, frontal-view photographs were taken of posed smiles of 100 Persian women 3 months after completion of their orthodontic treatment. A total of 153 laypeople aged over 15 years were requested to score each smile in terms of attractiveness using a visual analogue scale (1-10). Next, 25 photographs that acquired the lowest score (group A) and 25 photographs that acquired the highest score (group B) were chosen and evaluated by 3 orthodontists regarding parameters related to an attractive smile. Data were analyzed using SPSS version 18.

RESULTS

The mean buccal corridor space in group A was significantly greater than that in group B (P = 0.004). The correlation of lip line and study group was significant such that 60% of patients in group B had a moderate lip line (P = 0.005). The difference in other parameters was not significant between the 2 groups (P >0.05).

CONCLUSIONS

The buccal corridor space and lip line are important factors affecting smile attractiveness of Persian women. According to the opinion of the laypeople, smaller buccal corridor space and moderate lip line yield a more attractive smile. Thus, these parameters should be taken into account in the orthodontic treatment of Persian women.

Do various degrees of tooth decalcification affect orthodontists', general dentists' and laypersons' ratings of smile esthetics?

OBJECTIVES

To compare the effect of various degrees of decalcification after orthodontic treatment (white spot lesions) on orthodontists', general dentists', and laypersons' ratings of smile esthetics.

MATERIALS AND METHODS

Eight photographs representing incrementally altered tooth decalcification lesions of maxillary anterior teeth ranging from mild to severe were shown randomly to the study participants. Photographs were rated by a matched sample of orthodontists (N = 42), general dentists (N = 52), and laypeople (N = 58). A visual analogue scale (VAS) was used to assess perceptions of smile esthetics.

RESULTS

The three groups of raters could distinguish between different decalcification levels. Raters gave more negative scores as the decalcification level increased.

CONCLUSIONS

The three groups of raters were able to distinguish between various degrees of decalcification lesions. General dentists were the most critical of all groups when rating decalcification lesions.

Lip Repositioning Surgery Using an Er,Cr:YSGG Laser: A Case Series

Excessive gingival display (EGD) is a common esthetic concern. Lip repositioning surgery (LRS) was introduced as one of the treatment options to manage EGD. LRS can be used for skeletally and/or muscularly induced EGD. The present case series applied LRS using an Er,Cr:YSGG laser to treat 24 patients with minor vertical maxillary overgrowth or a hypermobile lip. At 6 months, the gingival display had decreased by 3.79 ± 1.59 mm (mean ± standard deviation), and the visible lip body when smiling had increased by 1.23 ± 0.74 mm. A questionnaire revealed that the level of satisfaction with the smile increased among the patients and that they had a positive attitude toward Er,Cr:YSGG laser-assisted LRS.

A Modification for Treatment of Excessive Gingival Display: Tooth-Based Lip-Repositioning Technique

Exposure of maxillary gingiva more than 3 mm while smiling is referred to as "excessive gingival display" or "gummy smile." Various treatment options for excessive gingival display are published in the literature, including lip repositioning, crown lengthening, botulinum toxin-A injections, and orthognathic surgeries. This case report aims to present a novel approach to the lip-repositioning procedure for treatment of excessive gingival display. The patient, who visited the department to demand a more esthetic smile, was diagnosed with excessive gingival display caused by hyperactivity of upper lip muscles. Lip repositioning procedure was considered. While evaluating the patient's smile, the amount of gingival display for each tooth region varied. A novel tooth-based modification was planned for the patient for a more precise result. No complication was noted during 10- and 30-day follow-ups. The amount of gingival display while smiling was less than 3 mm for each tooth region. The tooth-based lip-repositioning technique may provide an opportunity to more precisely treat patients with gummy smile.

Applying Classical Esthetic Principles to Create a Predictable Illusion of Symmetry While Using Digital Technology

Having a thorough understanding of classical esthetic principles, including basic tooth shape and form rules, is crucial for clinicians to achieve successful esthetic outcomes, even when implementing digital technologies in their dental offices. The use of advanced, cutting-edge digital tools does not negate the need to adhere to timeless fundamentals of esthetic dentistry. This article reviews key esthetic principles and describes their application in treating a challenging cosmetic case. Showcasing the use of smile design software, the case illustrates the diagnosis, planning, and clinical execution used to mask a congenitally missing lateral incisor while preserving the natural dentition on the contralateral side. The principles of symmetry and harmony are employed to create a smile in which the restorative dentistry would be imperceptible and the remaining dentition protected from structural compromise.

Perceptions of Dentists and Non-Professionals on Some Dental Factors Affecting Smile Aesthetics: A Study from Vietnam

Aim: It is important to meet the aesthetic expectation regarding the smile concept of both dentists and non-professionals after treatment is complete. Therefore, the study aims to evaluate the effects of altered displays in incisors, gingival margin, and other smile-related-factors on dentists’ vs. non-professionals’ aesthetics perceptions. Materials and method: We altered the features of 42 digital smile photographs to generate the changed displays in incisors, gingival margin, and other smile-related-factors. Then, these altered photographs were presented to 51 dentists and 51 non-professionals, and each picture was rated by each participant with a visual analog scale ranging from 0 (very ugly) to 100 (very beautiful). Results: We found that the alterations in incisors, gingival margin, and other factors affected studied groups’ aesthetic perception of smile. The ugly smile threshold rated by both groups for crown length of maxillary central incisors was 2.0 mm. This threshold was 2.5 mm for dentists, with moving the gingival margin of maxillary lateral incisors to the incisal ridge. The ugly thresholds for other smile-related-factors were different between studied groups; for example, the ugly thresholds for gingival exposure levels were 3 and 4mm for dentists and non-professionals, respectively. Thus, our data indicate that altered displays in incisors, gingival margin, and other smile-related-factors affected perceptions of both studied groups on smile aesthetics, but dentists tended to feel more refined than non-professionals. Dentists and non-professionals had significantly different aesthetic perceptions of the alteration of the gingival exposure level. Conclusion: Both dentists and non-professionals’ perceptions should be fully considered during orthodontic and prosthodontic treatment to achieve optimum aesthetic results.

An Improved Direct Injection Technique With Flowable Composites. A Digital Workflow Case Report

This article presents a clinical technique based on a case report for restoring the contours and shape of the upper teeth involved in the smile display of a young patient. After planning the treatment for the patient using digital tools (Digital pictures, Digital Smile Design, digital waxup, three-dimensional [3D] printed models, mockup), the upper teeth were restored using an improved injection technique. This improved technique involves the direct injection of flowable composite resin using clear polyvinyl siloxane molds made from 3D-printed models of the patient. The details and benefits of this new technique are described in the article.

[Application and exploration of Smile Lite MDP portable photography system in aesthetic photography of anterior teeth]

OBJECTIVE

To explore the possibility of the Smile Lite MDP (Smile Lite Mobile Dental Photograph) portable dental photography system applying in anterior teeth aesthetic photography, and to provide the chance to simplify aesthetic photography process and facilitate communication among patients, dentists and dental technitians.

METHODS

The Smile Lite MDP photography system combined with the smartphone were used to photograph the front occlusal phase photos of anterior teeth. The photographic conditions including the color temperature parameter, the Smile Lite MDP light position and the intensity settings were explored. The best photographic conditions were chosen by blind evaluation within experienced dentists and technicians through the method of the visual analogue scale/score (VAS) evaluation, which went through statistical analysis to figure out the optimum photograghic conditions. Smile Lite MDP photography system was used to photograph the front occlusal phase photos of anterior teeth under the optimum parameter by different magnifications. The width/height ratio of the central incisor and the front width ratio of the upper anterior teeth in those photos were measured and calculated respectively. The accuracy of the anterior teeth photos taken by Smile Lite MDP photography system was analyzed based on the photographs taken by digital single lens reflex (DSLR) camera.

RESULTS

The optimum color temperature parameter of Smile Lite MDP portable camera system was 5 000 K, the optimum magnification was 4 times, the best light position was the side lights of Smile Lite MDP, the optimum intensity of lights was 2 grades. Photos taken by the optimum parameters won the highest score during the VAS evaluation and the result of statistical analysis had significant difference compared with other groups (P<0.05). When comparing the photos of the upper anterior teeth taken by the Smile Lite MDP portable photography system using 4 times magnification or by DSLR using the standard parameters, there was no significant difference neither in the width/hieght ratio of the central incisor nor in the front width ratio of the upper anterior teeth (P>0.05).

CONCLUSION

The Smile Lite MDP portable dental photography system applying in anterior teeth aesthetic analysis photography was capable to show the color and shape of anterior teeth in an accurate way by using the right photography parameters. Therefore, Smile Lite MDP portable dental photography system was considered to be a simple and easy photographic tool in clinical work.

The Eye-Tracking Study of the Impact of the Gingival Margin Height of Maxillary Lateral Incisors

The objective of this study was to verify differences in eye-tracking metrics and subjective smile esthetic ratings between general practitioners, orthodontists, and laypersons in cases of maxillary lateral incisor gingival margin deviations. Unilateral apical and incisal gingival margin deviations of 1, 2, and 3 mm were digitally produced in pictures of a man and a woman smiling. Specific areas of interest (AOIs) were created in each picture. Eye-tracking metric data included the time to first fixation (TFF) and number of fixations (NF). A specific sensor and software were used to acquire information on the eye movements. Data on the smile esthetic ratings were obtained using a visual analog scale (VAS). Analysis of variance and Pearson correlation were applied. The TFF on the AOIs in the mouth was shorter for general practitioners and orthodontists, signifying that general practitioners and orthodontists rapidly perceived the features in these areas, while for laypersons, the TFF was shorter for the AOIs of the eyes (P < .05). The NF was greater on the AOIs in the mouth for general practitioners and orthodontists, whereas to the laypersons, the NF tended to be greater on the AOIs in the eyes. Mean VAS scores differed between observer groups (P < .05). For the male picture, the 1-mm and 2-mm apical gingival margin deviations received the highest scores from the laypersons, while for both female and male pictures, the 1-mm apical deviation received the highest scores from the general practitioners and orthodontists. Higher VAS scores resulted in longer times that general practitioners and orthodontists spent looking at the gingival margin changes. General practitioners and orthodontists differ from laypersons in their perceptions of smile esthetics. Eye-tracking metrics revealed that the AOIs in the mouth aroused greater interest from the general practitioners and orthodontists, and this interest became greater as the gingival margin deviations increased to 3 mm. Laypersons fixated more on the AOIs of the eyes. The VAS scores indicated that general practitioners and orthodontists were more critical than laypersons, accepting smaller deviations in the gingival margins of the maxillary lateral incisors.

Ideal vs adapted digital smile diagnosis in multidisciplinary cases during clear aligner treatment

A digital smile diagnosis based on Digital Smile Design (DSD) concepts reinforces the predictability and precision of orthodontic and multidisciplinary cases as it allows more accurate planning from an esthetic point of view. The intention of this clinical case series was to verify the relationship between the ideal and adapted smile in three orthodontic multidisciplinary cases treated using the Invisalign system in order to have a better understanding of the correlation between the several smile components. The ideal smile construction requires face, lips, gingival tissue, and tooth analysis and evaluation, as well as the appreciation of how all these aspects occur together. When the ideal smile line is not achievable in difficult clinical situations, the treatment goal would be an adaptation to the same line that supports a more predictable movement range. These DSD and orthodontic concepts should be primarily applied, since all intermediate involvement, as well as the final outcomes, are essentially planned from the beginning in clear aligner treatments. The presented case series allowed the authors to understand the importance of these digital diagnostic tools in dealing with certain particularities in orthodontic clear aligner treatments, both at the beginning and during the refinement/finishing stages.

Digital dental workflow for a smile makeover restoration

This article describes a novel concept for treatment planning and execution in the digital era. The aim of the presented workflow was to design, plan, communicate, perform, fabricate, deliver, and maintain a smile makeover restoration entirely through digital technology. The interdisciplinary treatment plan is described from the planning through the diagnostic mock-up to the final restoration. In digital designing, the dental morphology and tooth shape seen by the clinician and technician are interpreted by the computer as a 3D geometric mathematic model. Controlling the geometry provides freedom for the clinician to develop a restorative digital plan that can be followed throughout the patient's treatment. Moreover, new ceramic materials used with computer-assisted techniques have considerably broadened the choices for dental teams and have enhanced the results that can be achieved.

Evaluation of the effect of tooth size on smile attractiveness fromthe perspective of art students, dental students, and laypeople in Sanandaj, Iran, 2017

INTRODUCTION

An attractive smile helps people to feel more self-confident and look younger and more attractive. Smile evaluation and smile design are therefore important aspects of restorative and orthodontic diagnosis and treatment planning.

AIM

The purpose of this study was to determine the influence of tooth size on smile attractiveness.

MATERIALS AND METHODS

The study was conducted in 2017 in Sanandaj, Iran. The participants were selected by convenience sampling among 50 dental students, 50 art students, and 50 laypeople. A color photograph of a posed smile was chosen from the internet. The maxillary anterior dentition was digitally altered to produce different tooth sizes with width-to-height ratios of 65%, 70%, 75% (original photograph), 80%, 85%, and 90%. Six images of each subject were paired into 16 possible combinations and presented to three groups (dental students, art students, and laypeople). The Wilcoxon signed-rank test was used for data analysis.

RESULTS

Statistical analysis showed that the width-to-height ratios of 65% and 70% for the maxillary anterior teeth was considered least attractive by the participants in all three groups.

CONCLUSION

Minimal tooth size should be taken into account during restorative treatment planning, and excessive tooth proportions should be considered esthetically problematic.

Harmony of smile design in the facial context

OBJECTIVE

The aim of this study was to create mathematical modeling to generate statistical models that reliably and quickly identify facial type while smiling. This analysis enables the creation of a digital design for the prosthetic restoration of the anterior teeth.

MATERIALS AND METHODS

The study involved the computer analysis of 91 facial images. Through mathematical modeling, digital facial maps were generated consisting of 27 landmark points and 12 basic lines determining the facial type. Four main facial types were defined for the purposes of this study: strong, dynamic, delicate, and calm. Selected data were recorded in a database and analyzed using IBM SPSS Modeler software.

RESULTS

A varying number of combinations characterize the face; 61.5% of people have the features of two facial types, and 38.5% of three facial types. The overall analysis of the data for both genders shows the most accurate model for predicting facial type by digital facial map is the created algorithm C5.1 (classification tree), with a general prediction accuracy of 84.3%.

CONCLUSION

Dental Anatomical Combinations with Rebel Simplicity systems is a constructive way to ensure harmonious unity between the teeth and the facial type. Digital facial maps provide reliable and fast identification of the facial type while smiling. This analysis enables the creation of a digital design for the prosthetic restoration of the anterior teeth.