Laypeople's perceptions of frontal smile esthetics: A systematic review

What comes first: teeth or face? Recommendations for an interdisciplinary collaboration between facial esthetic surgery and dentistry

OBJECTIVE

The aim of the present study was to provide recommendations in order to facilitate communication between dental professionals and surgeons who are collaborating in the field of dentofacial esthetics.

CLINICAL CONSIDERATIONS

Smile esthetics are beyond the scope, both of the surgeons who are collaborating with facial esthetics and of the dentists, as a wide range of treatment options from both sides is available. It can be difficult for the surgeon or the dentist that first comes in contact with the patient to conduct an individualized global treatment plan, in order to find out how the various phases of the treatment can be sequenced, as a workflow for an efficient interaction between facial surgery and dentistry still does not exist in the scientific literature.

CONCLUSIONS

Facial cosmetic procedures and dental treatment have to be planned as individual elements of the whole dentofacial esthetic rehabilitation. The treatment has to be initiated with the design of the smile and the intraoral mock-up, followed by the required surgical interventions, and to be finished with the delivery of the definitive dental restoration.

CLINICAL SIGNIFICANCE

Dentofacial esthetics require comprehensive communication between surgeons and dentists. Following the proposed recommendations, an individualized interdisciplinary treatment plan can be conducted, defining the role of each specialty.

White spot lesion-related perception of aesthetics and treatment satisfaction among orthodontic patients, orthodontists and other dental specialists

OBJECTIVE

To investigate the impact of various degrees of white spot lesions (WSLs) of maxillary anterior teeth on the aesthetic perception and treatment satisfaction among orthodontic patients, orthodontists and other dental specialists and to evaluate the differences among the three groups.

METHODS

A total of 45 orthodontic patients (OP), 45 orthodontists (OR) and 45 other dental specialists (OS) were recruited. Subjective evaluations of perceived aesthetics and treatment satisfaction were performed towards eight digitally generated photographs of maxillary anterior teeth with incremental degrees of WSLs using a numerical visual analogue scale (VAS) from 0 to 100. Data were collected and analysed with descriptive statistics, repeated one-way analysis of variance and multivariable generalized estimating equations.

RESULTS

A total of 135 valid questionnaires were collected. Regarding aesthetic scores for WSLs, OP gave more positive scores than OR and OS (p < .05) towards excessive white spot formation without colouration and were more tolerant than OR (p < .05) towards excessive white spot formation with slight colouration. The level of treatment satisfaction for slight to severe WSLs without cavitation was higher in OP than OR. Patients with higher education levels had more negative scores for aesthetic perception and treatment satisfaction (p < .05). Patients who brushed teeth more frequently scored lower in treatment satisfaction (p < .05).

CONCLUSIONS

Orthodontists were the most critical when evaluating aesthetics and treatment satisfaction for slight to severe WSLs without cavitation. For orthodontic patients, better oral hygiene habits and higher education levels were associated with more critical attitudes towards WSLs.

Aesthetic assessment of maxillary lateral and canine implant-supported crowns by laypersons and orthodontists

INTRODUCTION

The objectives of this study were to evaluate how laypersons and orthodontists evaluate and rank aesthetic parameters of an implant-supported crown (ISC) on the canine position (ISC-C) and lateral position (ISC-L).

METHODS

A digital survey of 11 cases, 5 ISC-C, 5 ISC-L and 1 control case without ISC, was distributed to 207 laypersons and 296 orthodontists. All cases included one extraoral photograph and three intraoral photographs. The respondents were asked to identify the ISC and to evaluate the aesthetic parameters regarding colour of the implant (CI), shape of the implant (SI) and gingival colour around ISC (GCI). Differences within and between the groups were tested using Chi-2-test and Independent-Samples t-test.

RESULTS

All invited laypersons and 184 orthodontists (62% response rate) answered the survey. Orthodontists (89%) more correctly identified the ISC, regardless of its position, than laypersons (50%) (p < 0.001). Both laypersons (54%) and orthodontists (23%) rated higher proportions of acceptance of CI, SI and GCI in favour for the ISC-L than ISC-C (laypersons: 40%, orthodontists: 10%) (p < 0.001). Assessing each parameter separately, orthodontists rated higher for ISC-L, compared to the ISC-C (p < 0.001). In general, laypersons and orthodontist ranked tooth colour (mean, standard deviation [SD]:8.0,1.5 and 9.0, 1.0) and tooth shape (mean, SD: 8.0, 1.7 and 8.8, 1.2) as aesthetically higher than the gingival colour (mean, SD: 7.2, 2.2 and 8.0, 1.7) (p > 0.001).  Conclusion: Laypersons and orthodontists consider the ISC-L as aesthetically more preferable, compared to the ISC-C.

Digital resources for surgical and restorative treatment of excessive gingival display in one session

OBJECTIVE

This article aims to showcase the implementation of a digital workflow in addressing a case of multifactorial excessive gingival display in a patient with high esthetic demands, incorporating both surgical and restorative interventions in a single session.

CLINICAL CONSIDERATIONS

A 28-year-old female patient presented with excessive gingival display, attributed to a combination of short teeth due to altered passive eruption, lip hyperactivity, and a sub-nasal depression that lodged the upper lip during spontaneous smiling. The multidisciplinary treatment strategy encompassed surgical crown lengthening, the placement of a biovolume in the maxillary concavity, and the rehabilitation of the six anterior teeth with direct composite resin, all done in a single session. Smilecloud Biometrics was used to digitally plan the smile, and the final wax-up/mock-up was approved by the patient prior to any irreversible procedure. A digital planning center (GuiderLab) enabled the materialization of the virtual planning and the printing of the periodontal surgical guide, the biovolume, and the resin layering guides for the restorative technique.

CONCLUSIONS

Adopting a digital workflow in multidisciplinary cases with excessive gingival display leads to predictable and more expedited outcomes, ensuring a favorable result between soft and hard tissues.

CLINICAL SIGNIFICANCE

Excessive gingival display is a condition with multifactorial etiologies, including dentoalveolar, periodontal, skeletal, or muscular origins, or a combination of these factors. The diagnoses of altered passive eruption and a hypermobile upper lip are common in daily clinical practice and can be successfully managed through surgical crown lengthening and filling of the maxillary concavity, respectively. To achieve the desired outcome, restorative procedures often complement these surgical interventions.

Smile attractiveness in patients treated with or without 4 premolar extractions: A 36-year follow-up

INTRODUCTION

This study aimed to assess the smile attractiveness in patients treated with or without 4 premolar extractions at a 36-year follow-up.

METHODS

The sample comprised 52 patients with Class I and II malocclusion divided into 2 groups. Group 1 consisted of 15 patients treated without extractions (10 females and 5 males), with a mean pretreatment, posttreatment, and long-term posttreatment (T3) age of 13.2, 15.1, and 49.8 years, respectively. The mean treatment time was 1.9 years, and the mean long-term follow-up period was 34.7 years. Group 2 consisted of 37 patients (25 females and 12 males) treated with 4 premolar extractions, with a mean pretreatment, posttreatment, and long-term posttreatment age of 13.3, 15.7, and 53.6 years, respectively. The mean treatment time was 2.3 years, and the mean long-term follow-up period was 37.9 years. The mean retention time was 2 years for both groups. Frontal smiling photographs were obtained at long-term follow-up. Smile attractiveness was evaluated in an online questionnaire in which the evaluator could rate the smiling photographs with a 10-point scale. The randomly selected evaluator sample consisted of 62 laypeople, 33 dentists, and 89 orthodontists. Independent t tests, 1-way analysis of variance, and Tukey tests were used for intergroup comparisons at P <0.05.

RESULTS

The smile attractiveness on the long term was similar in the groups treated with 4 premolar extractions (4.70 ± 1.35) or without extractions (4.51 ± 1.46). Women and orthodontists were more critical in assessing smile attractiveness than men, dentists, and laypeople.

CONCLUSIONS

After long-term posttreatment, the smile attractiveness was similar in patients treated with 4 premolar extractions or without extractions.

The Use of Eye-Tracking Technology in Dento-Maxillofacial Esthetics: A Systematic Review

The use of eye-tracking technology in dental esthetics has gained popularity over the past decade because of its ability to assess observers' visual preferences in an objective manner. The goal of this study was to provide a comprehensive review of eye-tracking studies in dentistry, which could provide a reference for the rational and effective application of eye-tracking technology by dentists in the future. A comprehensive search of articles on eye tracking, published from January 1946 to June 2023, was conducted across several databases using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The major criterion for inclusion was that the study evaluated the use of eye-tracking technology in the field of dentistry. Two independent reviewers screened the eligible studies. A total of 67 articles were identified, 41 of which met our inclusion criteria. The most common application of eye tracking was the assessment of perceptions of changes in specific dental conditions among different classes of observers. Overall differences between groups (different classes of observers, different types of conditions) among different areas or regions of interest were analyzed. This systematic review demonstrated the utility of eye-tracking technology as a quantifiable objective assessment and emerging research tool for evaluating outcomes in several domains of dentistry.

The impact of dental midline angulation towards the facial flow curve on the esthetics of an asymmetric face: Perspective of laypeople and orthodontists

PURPOSE

The objective of the present article was to evaluate the ımpact of dental midline angulation in asymmetrical faces.

MATERIALS AND METHODS

A full-portrait image was used to create a set of digitally modified images with a different degree of facial asymmetry, towards the right and the left side of the face respectively. Half of the images were designed with an equivalent angulation of the dental midline in respect to the curve of the lower third of the face and half of them without. Through a web survey, 250 laypeople and 250 orthodontists were asked to assess the attractiveness of each image separately.

RESULTS

As the asymmetry of the face was increased, facial attractiveness was further decreased both for laypersons and orthodontists. For each one of the modified images, when the dental midline was following the curve that was formed from the inclination of the simulated asymmetry of the face, the smile attractiveness scores were significantly higher compared to a straight dental midline.

CONCLUSION

Facial asymmetries derived from the inclination of the nose, the chin and the commissural line of the lips can significantly affect the smile attractiveness. An orientation of the dental midline towards the facial asymmetry in order to follow the facial curve, can be beneficial for the smile attractiveness compared to a perpendicular to the face dental midline. During the design of a smile, clinicians have to take into consideration deviations in facial midline, in order their restorations to be in harmony with the rest of the face.

CLINICAL SIGNIFICANCE

During the design of a smile, clinicians have to take into consideration deviations in the facial midline, in order their restorations to be in harmony with the rest of the face.

Laypersons' Assessment of Smile Esthetics in Young Individuals in Ha'il, Saudi Arabia

INTRODUCTION

When planning esthetic dental treatments, understanding smile preferences is important for dental professionals. This study aimed to evaluate the impact of selected smile characteristics on the attractiveness of young Saudis as assessed by Saudi laypersons and explore gender-preferred changes in smile attractiveness.

METHODOLOGY

This observational study assessed the dynamic smile attractiveness of 168 Saudi individuals (84 males and 84 females), selected through non-probability convenience sampling. Dynamic smiles were elicited by viewing comedic content and captured with a camera standardized for consistent positioning. Videos were edited and adjusted to images, and the frames with the most pronounced smiles were chosen. The intra-rater reliability was assessed using intra-class correlation coefficients (ICCs) and Cohen's kappa tests (κ). The highest and lowest 25th percentiles were categorized as attractive and unattractive smiles, respectively, on the visual analog scale (VAS) by laypersons. Six smile characteristics - anterior smile line, smile arc, upper lip curvature, posterior teeth displayed, smile index, and smile symmetry - were quantitatively evaluated from these images for each participant and classified into attractive and unattractive groups based on laypersons' VAS evaluations. Continuous variables were tested with the Mann-Whitney U test, and for the categorical variables, the Chi-square test was applied. The significance was set at 5%.

RESULTS

 The four randomly selected out of the 22 raters had good VAS reliability; ICCs varied from 0.661 to 0.94, with an average of 0.737, and Cohen's kappa tests for smile characteristics showed values from 0.617 to 0.89. Good agreement was also found with the smile index, with ICCs of 0.775, and dynamic smile symmetry, with ICCs of 0.872. Laypersons rated female smiles as more attractive compared to male smiles (P = 0.004). Low or average anterior smile lines (P = 0.001 for males; P = 0.03 for females), parallel smile arcs (P = 0.001 for males; P = 0.02 for females), and higher smile indexes (P = 0.001 for males; P = 0.004 for females) were significantly attractive, showing no significant gender differences.  Conclusions: Laypersons reliably rated the young Saudis' dynamic smiles as attractive. Of the rated smile characteristics, those with a low or average anterior smile line, parallel smile arcs, and a larger smile index were deemed more attractive. This study's findings show no significant gender differences in the impact of the studied smile characteristics on attractiveness. This study's findings can help dental professionals customize treatment plans that meet patients' expectations.

Perceptions in Digital Smile Design: Assessing Laypeople and Dental Professionals' Preferences Using an Artificial-Intelligence-Based Application

Digital Smile Design (DSD) is used in many fields of dentistry. This prospective observational study assessed laypeople's and dental professionals' perceptions of a DSD application. SmileCloud, an online DSD platform, was used to create two different designs for three patients; after that, the participants, in a 30-question online illustrated survey, were asked about the most attractive design and other features of the smile. Dentists' and laypeople's perceptions about specific DSD features were assessed. The Kolmogorov-Smirnov normality test was used. Descriptive and crosstab analyses compared the respondents' opinions for each statement. Chi-square tests were used to determine the relationship between the questions and any association with age, gender, and profession. The test results were rated as significant at a p-value < 0.05. A total of 520 participants (dental professionals, students, dental technicians, and laypeople) were enrolled. The statistically significant features were self-esteem related to appearance (p = 0.05), facial and smile symmetry (p = 0.42, p < 0.0001), tooth color (p = 0.012), and symmetry of gums (p < 0.001). For each patient, the design with dominant round upper incisors and perfect symmetry was preferred (p < 0.001). Digital pre-visualization benefits diagnosis and enriches treatment planning. The dentist-dental technician-patient team should be involved in the decision-making process of pre-visualization.

Malocclusion or laterorhinia: Which one impacts aesthetic facial perception the most?

INTRODUCTION

This study aimed to evaluate the perception of facial attractiveness when nose and teeth, together or isolated, present different degrees of disharmony. The secondary objective was to compare the perception of laypersons with that of dentists.

MATERIALS AND METHODS

This cross-sectional observational study included 112 individuals (58 laypersons and 54 dentists) that evaluated 6 manipulated images of the face of the same model, scoring their attractiveness using 10 cm Visual Analogue Scales (VAS), with least and most attractive at the left and right anchors, respectively. The images contained manipulations performed only on the nose (laterorhinia) and mouth (misaligned teeth), as follows: (1) standard photograph, with symmetrical nose + aligned teeth; (2) 2 mm nasal deviation + aligned teeth; (3) 4 mm nasal deviation + aligned teeth; (4) symmetrical nose + misaligned teeth; (5) 2 mm nasal deviation + misaligned teeth and (6) 4 mm nasal deviation + misaligned teeth. We used the repeated measures ANOVA test and Tukey's post-test for intra-group comparison of the images. The independent t-test was used for inter-group comparison of each image.

RESULTS

In the laypersons' group, the highest grades were given to images with aligned teeth and the lowest to misaligned teeth (smallest mean difference = 2.88 cm). For this group, there was no statistically significant difference (P-values ranged from .988 to 1.000) between scores of the three images in which teeth were aligned (range of 7.70-7.78 cm). In the group of dentists, highest grades were given to images with aligned teeth and the lowest to misaligned teeth. Difference between images 3 and 4 was not statistically significant (P = .204). All other differences between any image of straight teeth and any image with misaligned teeth were significant and the smallest mean difference between the two groups of images was 1.87 (P = .039). However, in the images with aligned teeth, there was also a statistically significant difference with higher scores to the images with symmetrical nose in contrast with those with significant laterorhinia (mean difference = 1.03 cm).

CONCLUSION

Teeth disharmonies had a more negative impact on the aesthetic perception of the face than did nose deviations, for both dentists and laypersons.

Influence of facial width on the perception of lip protrusion and its differences between profile and 3-dimensional video clip

INTRODUCTION

This study evaluated the influence of facial width on the perception of lip protrusion and investigated the concordance between 2-dimensional (2D) profile images and 3-dimensional (3D) video clips in assessing lip protrusion.

METHODS

An Asian female standard head model was created using 3D modeling software. Eight head models were constructed by modifying the standard head model in terms of facial width (broad, neutral, and slim) and lip protrusion (retrusive, straight, and protrusive). Overall, 97 Asian raters rated the lip protrusion from the 2D profiles and 3D rotation video clips of the 9 models.

RESULTS

No significant differences were found in the perception of lip protrusion in terms of sex, age, or occupation. Compared with the 2D profiles, the 3D video clips were rated as more protrusive in 8 of the 9 head models, with the retrusive broad, retrusive neutral, straight broad, and straight slim faces showing statistical significance (P <0.01). The rating is significantly higher in slim faces than in broad faces across the 3 groups of 2D profiles (P <0.01). For 3D video clips, the rating was higher in slim faces than in broad faces in all 3 groups, whereas differences were significant in the straight and protrusive groups only (P <0.01).

CONCLUSIONS

In this study, 3D video clips were more sensitive to the perception of lip protrusion than were 2D profiles to some extent. The lips were rated relatively more protrusive in a slim face than in a broad face. Therefore, the relationship between facial width and lip protrusion should be considered in orthodontic treatment goals and treatment plans.

Layperson assessment of smile lines and upper lip combined images in smile esthetics

STATEMENT OF PROBLEM

The esthetic assessment of smile lines by laypersons is a subject of ongoing debate. However, smile lines often appear with different types of upper lip curvature, which further complicates the esthetic assessment process, and studies on this combination are lacking.

PURPOSE

The purpose of this clinical study was to investigate a layperson's esthetic perception of smile lines and upper lip combined images.

MATERIAL AND METHODS

Twenty-six smile images resulting from combinations of 3 upper lip types, 4 anterior smile line types, and 3 posterior smile line types were generated by an image editing software program. Eighty-three laypersons (39 men and 44 women; 18 to 35 years of age) completed rating images using a visual analog scale. Unattractive smiles were designated to be those with scores <50 and attractive ones with scores ≥50. Data were analyzed using 1-way analysis of variance and Bonferroni post hoc tests (α=.05).

RESULTS

High anterior smile line with gingival display >4 mm obtained significantly lower scores of <50 when combined with all upper lip curvatures (upward: 28.29 ±22.79, straight: 38.74 ±23.00, downward: 30.67 ±22.25, P<.01). High anterior smile lines with gingival display ≤4 mm combined with upward and straight upper lip curvature images obtained significantly higher scores, and all were ≥50 (upward: 63.24 ±22.22, straight: 61.40 ±21.58, P<.01).

CONCLUSIONS

From a layperson's perspective, high anterior smile lines with gingival display >4 mm combined with any lip type were determined to be unattractive. If gingival display was ≤4 mm combined with both upward and straight lip types, the smile was assessed as attractive.

Attractive combinations of female gingival displays, buccal corridor sizes, and facial heights according to orthodontists, dentists, and laypeople of different ages and sexes: a psychometric study

INTRODUCTION

Esthetics plays a crucial role in orthodontics and many other dental and medical fields. To date, no study has assessed the combined effects of the 3 facial features 'facial height, gingival display (GD), and buccal corridor size (BC)' on facial/smile beauty. Therefore, this study was conducted for the first time.

METHODS

In this psychometric diagnostic study, beauty of 27 randomized perceptometric images of a female model with variations in facial heights (short, normal, long), gingival displays (0, 2, 4, 6 mm), and buccal corridor sizes (2%, 10%, 15%, 20%, 25%) were evaluated by 108 judges (36 orthodontists, 36 dentists, 36 laypeople) using a 5-scale Likert scale (1 to 5). Combined effects of facial heights, GDs, BCs, judges' sexes, ages, and jobs, and their 2-way interactions were tested using a mixed-model multiple linear regression and a Bonferroni test. Zones of ideal features were determined for all judges and also for each group using repeated-measures ANOVAs and the Bonferroni test (α=0.05).

RESULTS

Judges' sex but not their age or expertise might affect their perception of female beauty: men gave higher scores. The normal face was perceived as more beautiful than the long face (the short face being the least attractive). Zero GD was the most attractive followed by 4 mm; 6 mm was the least appealing. BCs of 15% followed by 10% were the most attractive ones, while 25% BC was the worst. The zone of ideal anatomy was: long face + 0mm GD + 15% BC; normal face + 2mm GD + 15% BC; long face + 2mm GD + 15% BC; normal face + 0mm GD + 15% BC.

CONCLUSIONS

Normal faces, zero GDs, and 15% BCs may be the most appealing. Facial heights affect the perception of beauty towards GDs but not BCs.

Customized planning of the visible maxillary arch width in harmony with interparopia width and smile width for female facial aesthetics

BACKGROUND

The visible maxillary arch width (VAW) is an important aesthetic-determining feature. To date, there is no well-established methodology to determine the aesthetically optimal VAW in customized treatment planning.

METHODS

In this study, the common traits of the dentofacial configuration were investigated in most attractive Asian and Caucasian female smiles. The smiling photo of a subject was digitally modified based on combined variations of VAW, smile width (SW), transverse facial dimensions (TFD), and vertical facial dimensions. These modified photos were assessed for aesthetics. The aesthetically essential parameters were identified, and their mathematic correlations and reference ranges were determined for different vertical facial patterns. Using the obtained results, a mathematic guidance was constructed for customized smile designing. The applicability of this guidance was tested in Asian females.

RESULTS

The most attractive Asian and Caucasian female smiles have intraracial and interracial commonalities in the VAW-to-TFD ratios. The interparopia width (IPD) predominated over facial widths in determining well-matched VAW and SW. For optimal smile aesthetics, the VAW and SW were correlated as simulated by the formula 1.92 IPD ≤ VAW + 2.3 SW ≤ 2.17 IPD, plus the VAW-to-IPD ratio within 0.54 to 0.62 and the SW-to-IPD ratio within 0.61 to 0.71, ranges tailored to vertical facial patterns. This constitutes a mathematic guidance for customized planning of the aesthetically optimal VAW. This guidance was preliminarily validated to be applicable to Asian females.

CONCLUSIONS

The VAW-to-TFD ratios were essential for Caucasian and Asian female smile aesthetics. The mathematic guidance could serve as a reference for customized smile designs for Asian females.

Orthodontic clinicians' attitudes and knowledge of dentogingival aesthetics: A cross-sectional survey of BOS members

OBJECTIVE

To assess orthodontic clinicians' knowledge and attitudes towards dentogingival aesthetics and to explore characteristics that predict the knowledge of dentogingival aesthetics.

DESIGN

Cross-sectional questionnaire.

SETTING

On-line survey of members of the British Orthdontic Society.

MATERIALS AND METHODS

An 11-item online questionnaire was sent to orthodontic practitioners for completion. The questionnaire covered respondent demographics and questions relating to both knowledge and attitudes towards dentogingival aesthetics (six parameters). Descriptive statistics were calculated for study characteristics and summary values for the survey items. Responses to the eight knowledge-based questions were converted to a binary outcome (correct and incorrect answer). The maximum score that could be achieved was eight. Multivariable modelling was used in order to examine associations between the study characteristics and the aggregate score.

RESULTS

A total of 252 responses were obtained resulting in a response rate of 17%. Within this cohort, the respondents were primarily women (52.8%) and aged 30-40 years (35.7%). The mean score for the eight knowledge-based questions was 3.8 ± 1.8 (range = 0-8). Knowledge of the ideal gingival margin position of the anterior teeth was high (92.4%). Knowledge of the other five dentogingival aesthetic parameters was variable. In the multivariable analysis, lower knowledge scores were predicated by respondents who did not have a special interest in dental aesthetics (-0.54; 95% confidence interval [CI] = -1.01 to -0.07; P = 0.02), who could not recall attending courses, lectures or seminars on dental aesthetics in the past five years (-0.80; 95% CI = -1.43 to -0.17; P = 0.01) and with increasing age (-0.43; 95% CI = -0.62 to -0.23; P < 0.001).

CONCLUSION

Knowledge of ideal dentogingival parameters is generally suboptimal among orthodontists in the UK. The reported lack of knowledge of the ideal dentogingival parameters may also influence respondents' attitudes towards the importance of dentogingival aesthetics. Further teaching or courses related to dentogingival aesthetics is desired by orthodontic clinicians.

Reliability of the novel cleft lip and palate smile esthetic index (CLP-SEI)

BACKGROUND/OBJECTIVES

The aim of this research was to determine the reliability of a novel index for the assessment of smile esthetics in patients with cleft lip and/or palate (CL ± P) at the end of their multidisciplinary treatment, for use in clinical and academic settings.

MATERIALS AND METHODS

Five orthodontists, five periodontologists, five general practitioners, five dental students, and five laypeople rated the smiles of 10 patients with CL ± P twice at a 2 weeks interval. The rating scale consisted of four main categories: 1. nasolabial esthetics, 2. gingival esthetics, 3. dental esthetics, and 4. overall esthetics. A total of 15 parameters were rated. Intra- and inter-rater agreements were calculated using SPSS.

RESULTS

The inter-rater agreement varied between good and excellent whereby the orthodontists, periodontists, general practitioners, dental students, and laypeople obtained agreement scores of 0.86, 0.92, 0.84, 0.90, and 0.89, respectively. The intra-rater agreement was good with agreement scores of 0.78, 0.84, 0.84, 0.80, and 0.79, respectively.

LIMITATIONS

Smile esthetics were rated on static pictures, not in real life or by video recordings in a young adult population.

CONCLUSIONS/IMPLICATIONS

The cleft lip and palate smile esthetic index is a reliable tool for the assessment of smile esthetics in patients with CL ± P.

XGBoost-aided prediction of lip prominence based on hard-tissue measurements and demographic characteristics in an Asian population

INTRODUCTION

Prediction of lip prominence based on hard-tissue measurements could be helpful in orthodontic treatment planning and has been challenging and formidable thus far.

METHODS

A machine learning-based cross-sectional study was conducted on 1549 patients. Hard-tissue measurements and demographic information were used as the input features. Seven popular machine learning algorithms were applied to the datasets to predict upper and lower lip prominence. The algorithm that performed the best was selected for the construction of the prediction model. Evaluation of feature importance was conducted using 3 classical methods.

RESULTS

Among the 7 algorithms, the XGBoost model performed the best in the prediction of the distances between labrale superius or labrale inferius to the esthetics plane (UL-EP and LL-EP distances), with root mean square error values of 1.25, 1.49 and r2 values of 0.755 and 0.683, respectively. Among the 14 input features, the L1-NB distance contributed the most to the prominences of the upper and lower lips. A lip prominence predictor was developed to facilitate clinical application by deploying the prediction model into a downloadable tool kit.

CONCLUSIONS

The XGBoost model performed well with high accuracy and practicability in predicting upper and lower lip prominence. The artificial intelligence-aided predictor could serve as a reference for orthodontic treatment planning.

Smile Aesthetics Assessment in Patients Undergoing the Finishing Phase of Orthodontic Treatment: An Observational Cross-Sectional Study

Objective To describe the smile characteristics of patients entering the finishing phase of orthodontic treatment. Methods This observational study involved a non-probabilistic sample of 48 patients. Clinical records served as the basis for determining the type of treatment (with or without extractions). Photographs were analyzed to obtain smile variables. Dental casts and panoramic radiographs were evaluated to ascertain the cast-radiograph evaluation (CRE) index. Univariate and bivariate analyses were conducted at a significance level of 0.05. Results The study evaluated 24 men and 24 women, with an average age of 20.10 ± 6.78 years. Fifty percent of the patients did not undergo extractions, and the average CRE index for the sample was 34.83 ± 9.01. Regarding the smile, a medium smile line was prevalent in 66.7% of cases, and a non-consonant smile arc was observed in 58.3%. Significant differences in the smile arc were found between patients with and without extractions (p=0.019). Right and left buccal corridors measured 2.52 mm ± 1.52 and 2.43 mm ± 1.37, respectively. The upper dental midline deviated by 0.80 ± 0.91 mm and had an angulation of 1.65 ± 2.05º. Both variables showed significant differences between Class I and Class II patients (p=0.020; p=0.027). Symmetrical smiles were also observed (1.05 ± 0.17). Conclusions Based on our findings, clinicians should focus on the smile arc in patients who have not undergone extractions and on the midline inclination in Class II patients. These appear to be the most common areas for improvement in patients who are in the finishing phase of treatment. Additionally, considerable variability exists in the smile characteristics of patients still undergoing orthodontic treatment, leaving room for further enhancement of results.

Perception of laypersons, orthodontists, and oral and maxillofacial surgeons about the transverse occlusal plane

INTRODUCTION

Transverse occlusal plane (TOP) should be parallel to the true horizontal lines of the face (ie, the interpupillary line [IP] and commissural line [CL]). This study aimed to investigate the opinions of laypersons, orthodontists, and oral and maxillofacial surgeons about the impact of imbalanced IP and CL on facial attractiveness.

METHODS

We used a symmetrical face image as the reference. Then, using Photoshop software, we constructed the following 6 photographs: TOP roll relative to CL and IP (3° and 6°) with parallelism of CL and IP, CL roll relative to TOP and IP (3° and 6°) with parallelism of TOP and IP, TOP and CL roll relative to IP (3° and 6°). Consequently, the participants rated the photographs on the basis of their attractiveness. Kruskal-Wallis and Mann-Whitney U tests were used to compare the ratings.

RESULTS

One hundred thirty-one laypersons, 22 orthodontists, and 20 surgeons participated in this study. It was found that 51.1% of laypersons, 86.4% of orthodontists, and 70% of surgeons selected the reference photograph as the most beautiful, followed by the photograph with a 3° roll of CL relative to TOP, with parallelism of TOP and IP (29% of laypersons, 31.8% of orthodontists, and 35% of surgeons).

CONCLUSIONS

Most participants selected the reference photograph as the most beautiful and realized a roll in the horizontal planes up to 3°. The parallelism of the esthetic line of dentition relative to interpupillary is preferred over its parallelism relative to CL.

Maxillary Midline Diastemas in West African Smiles

The maxillary midline diastema (MMD) has experienced a renaissance in popular culture over the last 10 years. Current literature states that MMDs should be eliminated where possible or be reduced to 1 mm or less in width. This literature review explores the evidence for this in a West African population. A systematic search of the literature (Medline and Google Scholar) followed by a hand search was carried out to identify all papers evaluating perceptions of MMDs. In all, 209 papers were identified in the literature search, 8 of which met the inclusion criteria. The review revealed that midline diastemas are desirable in this specific population with a width of 2 to 4 mm deemed as attractive. As many as 95% of participants found the MMD beautiful, and as many as 95% would consider having one created artificially. The literature does not support the position that MMDs larger than 1 mm should always be treated to be perceived as attractive in this population. MMDs are accepted as attractive and should be considered a key feature in smile design for this population.

Perception of smile attractiveness among laypeople and orthodontists regarding the buccal corridor space, as it is defined by the eyes. An innovated technique

OBJECTIVE

To investigate whether there is a relationship between the distance between the iris and pupil with the ideal size of buccal corridors.

MATERIALS AND METHODS

A full-portrait image of a male Caucasian was used to create a set of 11 digitally modified images with different buccal corridor space. A web-based cross-sectional study was designed and distributed via an online survey to 200 laypeople and 200 orthodontists to assess image attractiveness, using a Visual analogue scale. For the statistical analysis, Wilcoxon signed-rank and Mann-Whitney U tests were used. The significance level was set at p < 0.05.

RESULTS

The response rate for laypeople was 70% (n = 139), while the rate for orthodontists was 73% (n = 146). For the layperson group, the maximum smile attractiveness score was 10% of buccal width reduction, compared to the iris-pupillary distance, while for the orthodontists, it was 20%. The attractiveness of the smile was significantly reduced in both groups when the buccal corridor width was increased in comparison to the iris-pupillary distance.

CONCLUSION

The length between the mesial part of the iris and the distal of the pupil, may constitutes a landmark for the estimation of the desired width of the buccal corridor.

CLINICAL RELEVANCE

Inter iris-pupillary distance can be the starting point in the smile designing process, in order to perform a facial driven selection of buccal corridor size.

The effect of torque and vertical position of maxillary canine on smile esthetics

INTRODUCTION

Regarding the key role of the maxillary canine in dynamic occlusion and smile esthetics, this study investigated the relation between smile esthetics and maxillary canine torque and vertical position from the viewpoint of orthodontists, general dentists, and laypersons.

METHODS

In this descriptive cross-sectional study, the close-up smile images have been changed using Adobe Photoshop (Adobe Systems, San Jose, Calif). Then, groups of 21 orthodontists, 20 general dentists, and 33 laypersons evaluated the smile attractiveness of the images using a digital version of a visual analog scale. Statistical analysis was performed using SPSS software (version 25; IBM, Armonk, Calif) and Shapiro-Wilk, analysis of variance, and Tukey post-hoc statistical tests. The significance level was set at 0.05.

RESULTS

There was no significant difference in the mean score between the 3 groups of observers regarding the changes in the canine vertical position in none of the variations (P >0.05). Regarding variations in torque, there was a significant difference between the 3 groups of observers in the bilateral 5° torque change. (P = 0.020).

CONCLUSIONS

Unilateral changes in the vertical position had lower scores, which shows that symmetry is very important in smile esthetics. In addition, laypersons did not find torque changes ranging between -15° to 15° a significant factor in smile esthetics. Overall, some adherence to these values will be acceptable in dental treatments.

An alternative approach for the surgical correction of unilateral crossbite

This case report aims to describe a modified surgically assisted rapid palatal expansion technique to treat an asymmetrical posterior crossbite with no mandibular shift without causing an interincisal diastema. A clinical patient with an asymmetrical crossbite, large tooth-size-arch length, and Bolton discrepancy is used to illustrate the modified technique. Instead of traditional osteotomies, in this technique, the osteotomy is done between the maxillary right canine and lateral incisor (connecting the piriform aperture to the alveolar process) along with a unilateral LeFort I osteotomy. The expansion forces are produced by the activation of a conventional hyrax appliance. The skeletal unilateral crossbite was corrected without major changes to the opposite side and without causing an anesthetic diastema between the maxillary central incisors. A mandibular incisor extraction produced the space needed to treat the tooth size-arch length and corrected the Bolton discrepancy. This allowed a successful treatment of the problems initially presented by the patient.

Factors affecting perception of laypeople and dental professionals toward different smile esthetics

Abstract Background

/purpose: Several factors such as identity, income, and age potentially associated with smile perceptions. This study aimed to identify the factors affecting the smile esthetic perception in different identities (layperson, general dentist and orthodontist) and to detect the extent of their association with smile perception.

Materials and methods

Extraoral photographs in frontal, lateral, and three-quarter views were shot and adjusted on Adobe Photoshop into 95 smile photographs with different smile patterns. Based on these photographs, the investigators were asked to fill the online questionnaire. Pearson chi-square test and logistic regression were used for statistical analyses.

Results

Identity, gender, age, and treatment experience were noted to affect smile esthetic perception. In addition, the perception of smile esthetics was significantly different among frontal, lateral, and three-quarters views regarding the arc ratio, most posterior teeth exposure, upper teeth exposure, and lower teeth exposure.

Conclusion

Identity, gender, age, and treatment experience influence the smile esthetics perception, with a significant difference in the results of the esthetic perception based on the 3 smile views. Of all demographic factors, identity had a strong relation to the perception of smile attractiveness. Nevertheless, additional studies are needed to realize how the demographic factors influence people's perception of smile esthetics, particularly in the three-quarter and lateral views.

Perception of Need for Further Refinement in a Clear Aligner Treatment among Orthodontists, Dentists and Laypeople: A Retrospective Study

Clear aligner treatment often requires further refinement to improve the orthodontic treatment outcome. However, the perceptions of treatment outcomes evaluated by orthodontists and dentists are sparse, and laypeople's perceptions have yet to be explored. Here, we explore the perceptions of orthodontists, dentists, and laypeople concerning the treatment outcomes achieved after completing the first sequence of aligners. This cross-sectional study involved 37 orthodontists, 67 dentists, and 93 laypeople. We administered an online questionnaire containing intra-oral photographs of nine completed cases with pre- and post-first sequences of aligners. As a control, we used a digital prediction system for the treatment outcome. Self-perception was reported using a visual analog scale. Both orthodontists and dentists had similar perceptions about treatment outcomes (p = 0.363) but significantly differed from laypeople (p ≤ 0.0001). Both orthodontists and dentists recommended further treatment; orthodontists were more critical than dentists (p ≤ 0.001). Orthodontists were more critical than dentists in their evaluations of the need for further treatments; however, their perceptions of treatment outcomes were similar. Laypeople were more satisfied with the treatment outcomes, were less concerned with occlusion, and were more focused on the aesthetic results of the treatment.

A digital workflow for pair matching of maxillary anterior teeth using a 3D segmentation technique for esthetic implant restorations

We investigated a state-of-the-art algorithm for 3D reconstruction with a pair-matching technique, which enabled the fabrication of individualized implant restorations in the esthetic zone. This method compared 3D mirror images of crowns and emergence profiles between symmetric tooth pairs in the anterior maxilla using digital slicewise DICOM segmentation and the superimposition of STL data. With the outline extraction of each segment provided by 100 patients, the Hausdorff distance (HD) between two point sets was calculated to identify the similarity of the sets. By using HD thresholds as a pair matching criterion, the true positive rates of crowns were 100, 98, and 98%, while the false negative rates were 0, 2, and 2% for central incisors, lateral incisors, and canines, respectively, indicating high pair matching accuracy (> 99%) and sensitivity (> 98%). The true positive rates of emergence profiles were 99, 100, and 98%, while the false negative rates were 1, 0, and 2% for central incisors, lateral incisors, and canines, respectively, indicating high pair matching accuracy (> 99%) and sensitivity (> 98%). Therefore, digitally flipped contours of crown and emergence profiles can be successfully transferred for implant reconstruction in the maxillary anterior region to optimize esthetics and function.

Effect of Ambient Lights on the Accuracy of a 3-Dimensional Optical Scanner for Face Scans: An In Vitro Study

Most 3D scanners use optical technology that is impacted by lighting conditions, especially in triangulation with structured-light or laser techniques. However, the effect of ambient lights on the accuracy of the face scans remains unclear. The purpose of this study is to investigate the effect of ambient lights on the accuracy of the face scans obtained from the face scanner (EinScan Pro 2X Plus, Shining 3D Tech. Co., LTD., Hangzhou, China). A head model was designed in Rhinoceros 5 software (Rhino, Robert McNeel and Associates for Windows, Washington DC, USA) and printed with 200 micron resolution of polylactic acid and was dented with 2.0 mm of carbide bur to aid in superimposition in software. The head model was measured by a coordinate-measuring machine (CMM) to generate a reference stereolithography (STL) file as a control. The face model was scanned four times under nine light conditions: cool white (CW), warm white (WW), daylight (DL), natural light (NL), and illuminant (9w, 18w, 22w). Scan data were exported into an STL file. The scan STL files obtained were compared with the reference STL file by 3D inspection software (Geomagic Control X version 17, Geomagic, Morrisville, NC, USA). The deviations and root mean square errors (RMSEs) between the reference model (trueness) and within the group (precision) were selected for the statistical analysis. The statistical analysis was done using SPSS 20.0 (IBM Company, Chicago, USA). The trueness and precision were evaluated with the one-way ANOVA with multiple comparisons using the Tukey method. For trueness, the scanner showed the lowest RMSE under the NL group (77.18 ± 3.22) and the highest RMSE under the 18w-DL group (95.33 ± 6.89). There was a statistically significant difference between the NL group and the 18w-DL group (p < 0.05) for trueness. Similarly, for precision, the scanner showed the lowest RMSE under the NL group (56.92 ± 4.56) and the highest RMSE under the 9w-CW group (78.52 ± 10.61). There was statistically significant difference between NL, 18w-WW, 18w-CW, 18w-DL, 22w-WW, 22w-DL, 9w-CW, 9w-WW, and 9w-DL (p < 0.05) for the precision. Ambient lights affected the face scans. Under the natural light condition, the face scanner had the best accuracy in terms of both trueness and precision. The 18w-DL and 9w-WW conditions showed the least trueness whereasthe 9w-CW and 9w-DL conditions showed the least precision.

Smile Design: Mechanical Considerations

Smile designing refers to the cosmetic and esthetic dental reconstruction that is visible during smiling. The use of modern digital tools requires adequate knowledge about the tooth shape and shade principles. Mechanical, biological, and psychological factors should be understood and tailor an individualized treatment accordingly to achieve pleasing esthetic outcomes. Dental therapy is becoming more appearance-driven, and thus, both patients and dental clinicians mainly emphasize on cosmetic dental and facial aspects of treatments.

Subjective and Objective Evaluation of the Symmetry of Maxillary Incisors among Residents of Southwest Poland

Dental aesthetics is an essential factor affecting people’s psychosocial wellbeing. One of the most critical components of an aesthetic smile is symmetry within the dentition. Dentists and orthodontists, unlike laypersons, are critical in assessing dental aesthetics. This study aimed to evaluate the accuracy of patients’ assessment of the symmetry of their maxillary incisors and some factors that influence it. The study was conducted on 83 participants aged from 11 to 39 years. First, the participants filled out a questionnaire to obtain patients’ opinions of the symmetry of their upper incisors. This stage was followed by an intraoral examination, during which we used a digital caliper to measure the width of four maxillary incisors. The data were entered into STATISTICA v. 13.3. The following conclusions were drawn from the study. First, the respondents were generally able to determine the asymmetry of the incisors. Second, among the maxillary incisors, the participants defined the symmetry of maxillary central incisors more accurately than the maxillary lateral incisors. The cut-off value for incisor asymmetry noticeable to a layperson is 0.2 mm for maxillary medial incisors and 0.55 for maxillary lateral incisors. Third, we found no dependence of the accuracy of the assessment of incisor asymmetry on the age of the subjects; however, in our study group, the age range (spread) was not significant, so further studies are recommended. Finally, results concerning the relationship with gender showed that males assess the level of symmetry of their maxillary incisors more accurately than females.

Analysis of Lower Facial Third and Dental Proportions to Predict Maxillary Anterior Teeth Width in the Pakistani Population

Obtaining the size of the maxillary anterior teeth when performing an esthetic smile rehabilitation can be a difficult task. Metrics based on dental proportions to assist in the process are required. This study aimed to evaluate the lower facial third proportions i.e., the interalar, interphiltral, and intercommisural distance with dental proportions in predicting maxillary anterior teeth width in Pakistani citizens. This analytical study was conducted on 230 participants. Front face and retracted smile photographs were captured for all the participants, followed by maxillary impression making. The cast was then converted to 3D models for analysis. The data were entered into SPSS-25. Descriptive statistics were carried out for frequency, mean, standard deviation, and percentage calculation of gender, teeth widths, horizontal mid facial proportions, and age of the participants. Independent t-test was applied for analysis of gender and arch side disparity. Regression analyses were performed to analyze the relationship between independent variables (gender, age, weight, and height) and dependent variables (horizontal facial proportion, dental proportion). A p-value of ≤0.05 was considered statistically significant. The interphiltral distance (IPLD) modified with Preston proportion (PRP) showed no significant difference with combined central incisor width, whereas a significant difference was found with golden proportion (GP), 70% recurrent esthetic dental (RED) proportion, and golden percentage (GM) modification. However, the interalar (IAD) and intercommisural distance (ICoD) modified with dental proportions showed a significant difference with maxillary anterior teeth width. The width of maxillary anterior teeth determined by plaster dental cast and 3D dental cast showed no significant difference. The ICoD, IAD, and IPLD could not be used to determine combined central incisor and intercanine width directly. The interphiltral distance modified with Preston proportion is a reliable method to predict combined central incisor width in the population studied. There was a significant difference in gender disparity when ICD, IAD, and IPLD were modified with dental proportions, except in the case of IPLD by the Preston proportion group. The golden proportion, 70% RED proportion, and golden percentage by lower facial third facial proportions are not reliable methods to predict maxillary anterior teeth width.

The Influence of the Maxillary Posterior Region on Smile Aesthetics in a Chinese Cohort

OBJECTIVES

The aim of this research was to establish standard norms for posterior smile-related characteristics including posterior smile line (PSL), the most posterior teeth displayed, buccal corridor ratio (BCR), and buccal corridor symmetry (BCS) and investigate its aesthetic contributions to smile attractiveness in a Chinese population.

MATERIALS AND METHODS

From digitally recorded dynamic smile videos of young Chinese participants, 188 standardised full-smile images were captured and then aesthetically evaluated by 22 laypersons using a visual analog scale (VAS). Four smile-related variables in the posterior region were analysed. VAS data were compared between subgroups to test the influence of these variables on smile aesthetics with significance level of P < .05.

RESULTS

The VAS scores of participants with high PSL were significantly lower than those with average or low PSL (P < .01), especially when they display average or low anterior smile line (P < .05). Smiles with the second premolar displayed obtained the highest VAS amongst the 3 subgroups (P < .05). No significant differences were found between the VAS scores of BCR and BCS (P > .05).

CONCLUSIONS

Maxillary posterior gingiva and teeth displayed influence smile attractiveness evaluated by laypersons, which should be given attention when treating patients with compromised aesthetics, especially those displaying average or low anterior smile lines.

A Cross-Sectional Online Survey on Knowledge, Awareness, and Perceptions of Hollywood Smile Among the Saudi Arabia Population

Background:

Hollywood smile has gained popularity in recent times to improve aesthetics among the general population. Since patients’ perceptions of dental aesthetics play a vital role in planning and evaluating cosmetic dental treatment, it is essential to understand their knowledge, awareness, and factors that influence their perceptions of dental aesthetics.

Objectives:

The objective of this study was to assess the knowledge, awareness, and perceptions of Hollywood smile among the general population in Saudi Arabia.

Methods:

A close-ended questionnaire consisting of demographic information and 20 questions related to Hollywood smile was circulated through social media in Saudi Arabia. Statistical analyses of the data obtained were performed using Statistical Package for Social Sciences software (SPSS version 17, USA). Frequencies, percentages, and mean and standard deviation were calculated using descriptive statistics. Pearson chi-squared test was employed to test the association between the demographic variables, such as age, gender, and education levels, with the questionnaire items.

Results:

A total of 4104 participants responded to the study questionnaire. The responses to the questionnaire revealed that nearly half of the participants were not satisfied with their dental appearance (48.6%). The majority of the participants had heard or known about Hollywood smile (98%). About 42% of study participants were aware of the complications involved in the procedure. The results revealed that the younger generation (18 to 30 years) had more awareness and felt more need for dental aesthetics (p=0.001). The proportion of male participants who underwent Hollywood smile correction were more than females (p=0.001). Graduates showed more awareness regarding smile, dental aesthetics, and Hollywood smile than the other categories (p=0.001).

Conclusion:

This study has shown that the younger generation, female participants, and graduates had more awareness regarding smile, dental aesthetics, and Hollywood smile.

The perception of smile attractiveness to altered vertical position of maxillary anteriors by various groups

There is a gap in research about the differences in smile attractiveness. The problem the study addresses is how the vertical canine and incisor position affect smile attractiveness. The aim of this study was to assess the perception of the smile attractiveness between Saudi laypersons, orthodontists, non-orthodontist, and various dental students levels, and to determine how the canine and incisor vertical positions affect the attractiveness of smile. The study is a cross-sectional survey and was conducted at King Abdulaziz University, Jeddah, Saudi Arabia. Six groups of subjects participated in the study: Orthodontic residents (n = 31), prosthodontic, restorative, periodontics specialties residents specialties residents (n = 30), interns (n = 31), fifth year students (n = 41), 6th year students (n = 39), and laypeople (n = 39). Participants were asked to rate the attractiveness of a smile of a female subject photographed using a Minolta DiMage 7i digital camera. The image had been manipulated to produce 2 sets of images; 1 to modify the incisors and 1 to change the canines. The subjects were asked to choose the most and least attractive picture. For the best incisor positions, only the laypeople and prosthodontics liked the original picture, the rest liked +0.5 mm which accentuate the smile curve and make it follow the lower lip line. For the worst incisor position, all groups did not prefer the minus 1.5 reversed smile. For the best canine vertical position, all groups preferred the original position where canine was at the level of the incisal plane. For the worst canine position, they all disliked the minus 1.5 reversed smile. Results confirmed past findings that orthodontists are in general more critical about smile attractiveness than laypersons, but just like other dental specialists. The findings can be used in the esthetic dentistry field, but further research on the study population based on other dental design parameters remain necessary.

Multidisciplinary design: Creating a common perspective in complex cases

OBJECTIVE

This clinical report describes and illustrates digital treatment planning and interdisciplinary orthodontic, surgical, and prosthetic treatment in a highly complex clinical case.

CLINICAL CONSIDERATIONS

Analogue design protocols through wax ups are highly variable, technique sensitive, and operator dependent. Digital smile design and treatment planning tools facilitate simplified processes through the use of natural tooth libraries, based on the specific esthetic and functional needs of the individual patient. The vast information compiled in the virtual patient and the treatment plan consolidated in the initial digital design facilitate true interdisciplinary treatment planning and execution, with all dental specialties involved, from orthodontic to surgical and prosthetic treatment.

CONCLUSIONS

Digital protocols and design tools provide clear clinical roadmaps for increased efficiency, precision, and predictability, vastly improving the quality of interdisciplinary patient care.

CLINICAL SIGNIFICANCE

While analogue protocols are technique sensitive and largely dependent on the operator, digital smile design, and treatment planning tools offer opportunities for truly patient-centered individualized care and interdisciplinary treatment.

Finite Element Analysis of Orthodontic Relapse in Different Maxillary Arch Form

Abstract Background: Orthodontic relapse is fairly common; however, the mechanisms between relapse and the dental arch form remain unclear. The purpose of our study was to establish three-dimensional (3D) finite element models of different dental arch forms after orthodontic treatment and to analyze the states of different arches applied with various sagittal forces.Methods: By calculating the equations of different dental arch forms and combining them with a full maxillary arch (14 teeth), 3D finite element models of square, oval, and tapered dental arches were established; they were designed to be subjected to anterior lingual, posterior mesial, and combined forces, respectively.Results: The von Mises stress and displacement of teeth under different forces were calculated for each loading scenario. Under the different forcing scenarios, all incisors had irregularity trends, and the inclination and intrusion of the canines were increased, and the premolars had a tendency to buccal or lingual crown tipping or even intrusion in our study. The tapered arch was the most stable and had the smallest displacement and von Mises stress, followed by the ovoid arch; the most unstable arch was the square arch.Conclusions: To achieve a stable orthodontic effect, a tapered or ovoid arch, rather than a square arch, should be chosen as the final outcome of treatment.

[Esthetic perception of the smile according to gingival exposure in university students in Lima, Peru, 2020]

Objective

To determine the esthetic perception of the smile according to gingival exposure in undergraduate university students of dentistry and other degrees of different ages and sex in Lima, Peru 2020, and descriptively evaluate the main variables such as age and sex.

Methodology

A woman's smile was photographed following esthetic parameters, digitally modifying gingival exposure and obtaining six digital images. The images were rated by 512 students of dentistry and other degrees by means of a virtual survey using the Visual Analog Scale (values 0 to 10).

Results

The students perceived the 0.5 mm gingival exposure smile as more attractive and the 2.5 mm gingival exposure smile as unattractive. According to age, students aged 18 to 23 years perceived the 0.5 mm gingival exposure smile as more attractive and the 2.5 mm gingival exposure smile as less attractive, while students aged 24 to 29 years perceived the 1 mm gingival exposure smile as more attractive and the 2 mm gingival exposure smile as unattractive. According to gender, both found the 0.5 mm gingival exposure smile more attractive and the 2.5mm gingival exposure smile unattractive.

Conclusions

University students of dentistry and other degrees had the same perception of the smile in relation to gingival exposure, with a smile of 0.5 mm gingival exposure being considered attractive and the 2.5 mm smile unattractive. Younger students considered the smile with 0.5 mm gingival exposure more pleasant. Students of both sexes had the same esthetic perception of the smile.

Effect of anterior overbite malocclusion on smile esthetics in adult patients

Objective

To investigate whether overbite affects smile esthetics.

Methods

This study involved 106 patients with complete pretreatment records. Lateral cephalometric tracings were used to measure hard tissue variables. Frontal smile and upper occlusal photographs were used to measure nine smile esthetic variables: arc ratio, number of teeth, upper incisor exposure, upper midline, buccal corridor ratio, smile index, archform index, lower teeth exposure, and interlabial gap. The patients were classified into three groups according to their overbites (B1: 0–4 mm, B2: >4 mm, and B3: <0 mm). Analysis of variance was performed to compare 14 cephalometric measurements and the 9 smile esthetic variables. Multiple linear regression analysis was performed to determine the influencing cephalometric factors.

Results

Only upper incisor exposure was significantly different among the groups. In the multiple linear regression analysis, upper incisor exposure was positively associated with the distance from the upper incisor to the palatal plane in Group B2. No significant correlations were observed between cephalometric measurements and smile variables in Groups B1 and B3.

Conclusions

Smile variables were not significantly different among patients with various overbite malocclusions with the exception of upper incisor exposure. Overbite malocclusions do not appear to influence smile esthetics in adult patients.

Factors influencing the aesthetics of smile: An observational study on clinical assessment and patient's perception

AIM

To clinically assess the aesthetics of smile and the possible influencing factors.

MATERIALS AND METHODS

In this explorative study, an initial questionnaire on demographic variables and perception of own quality of smile (Visual Analogue Scale) was administered by a first examiner. A second blinded assessor examined all patients and recorded clinical data. In addition, for each patient, the Smile Aesthetic Index (SEI) was calculated. Descriptive statistics and multilevel logistic models were performed.

RESULTS

One hundred consecutive subjects were enrolled. The mean SEI was 8.4 ± 1.2, while the mean patient's perception of smile was 7.1 ± 2.0. However, they did not correlate (r = 0.16 from -0.04 to 0.34; p = .12). Gingival recessions were perceived by 21.9% of subjects, tooth alignment by 38.6%, tooth dyschromia by 34.3%, and missing papilla/diastema by 26.7%. In particular, gingival recessions were perceived when they were deeper (p = .0342), located in the upper jaw (p = .0223), and corresponding to incisors (p < .0001) and canines (p = .0159) with respect to molars.

CONCLUSIONS

Clinical assessment and patient perception represent two important diagnostic phases. However, there is no correlation between them. Attention should be given to specific variables to provide the most comprehensive aesthetic analysis of smile.

Smile Attractiveness Evaluation of Patients Selected for a U.S.-Based Board Certification Examination

Objectives The aims of this study were to assess smile attractiveness of a collection of 68 smiling photographs of successfully treated cases submitted to the American Board of Orthodontics (ABO) clinical examination and identify variables that influence the assessment.

Materials and Methods A panel of 81 non-Caucasian assessors from various clinical disciplines were instructed to score the smile attractiveness on a visual analog scale from 1 (least attractive) to 10 (most attractive) and to select which components contributed to a lesser attractive smile. The mean, standard deviations (SDs), and quartiles of the smile attractiveness were obtained with descriptive statistics. Multilinear regression analysis was performed to investigate the scores of the perceived quality of smile attractiveness when the clinical disciplines and gender of the assessors were the factors taken into consideration. Receiver operating characteristic (ROC) curve was generated to establish the relationship between smile attractiveness and the achievement of a perfect smile.

Results The mean (SD) rating of each clinical photograph of the anterior occlusion on smiling ranged from 3.11 (1.47) as the least attractive smile to 7.59 (1.45) as the most attractive smile. The overall mean (SD) score for smile attractiveness was 5.30 (1.10). Problems associated with teeth, gingiva, and lips corresponded with a reduction of the smile attractiveness score by 1.56, 1.82, and 1.47, respectively. Gender was not associated with smile attractiveness ratings. Orthodontists, periodontists, and prosthodontists demonstrated no difference in the ratings, while plastic surgeons were more critical than orthodontists regarding smile attractiveness.

Conclusions This study suggested that only 2 out of 68 AOB validated treatment finishes had a perfect and attractive smile.

Influencing Factors on Aesthetics: Highly Controlled Study Based on Eye Movement and the Forensic Aspects in Computer-Based Assessment of Visual Appeal in Upper Front Teeth

First impressions are formed by the external appearance and, in this respect, essentially by an examination of the face. In the literature, the teeth, especially the maxillary front, are among an eye-catching and sensitive area that plays a significant role in the overall evaluation of appearance. In this study, the first eye fixation of 60 subjects with different levels of dental training (layperson, trained layperson, dental student, and dentist) is recorded using an eye-tracking system, and their subsequent evaluation of the images is recorded. Ten unedited original photographs of different maxillary anterior teeth and ten subsequently edited photographs will be used to evaluate forensic aspects such as the effect of symmetry and color on the overall evaluation. The results will be used to determine which areas of the maxillary anterior are demonstrably viewed and whether knowledge of dental esthetics influences evaluation and viewing.

Comparative analysis of smile aesthetics between top celebrity smile and a Southern European population

STATEMENT OF PROBLEM

The analysis of different parameters involved in the esthetic perception of the smile is important for the correct planning of cosmetic dental treatments.

PURPOSE

The purpose of this study was to analyze the differences in the main parameters of smile esthetics among celebrities identified as having the best esthetic smiles and a young Southern European population.

MATERIAL AND METHODS

The study consisted of a control group of 144 dental students from the University of Seville (69.4% women; 30.6% men) with a mean ±standard deviation age of 23.19 ±0.5 years and photographs of 58 celebrities identified as having the best esthetic smiles (74.1% women; 25.9% men) with a mean ±standard deviation age of 42.09 ±2.25 years. Photographs of the celebrities were obtained from the Internet, and standardized photographs were made of the control group. The variables measured were smile line, smile arc, incisal edges and lower lip relationship, smile width, dental midline deviation and tilting, buccal corridor widths, and angulation discrepancy between interpupillary line and commissural line and between interpupillary line and occlusal plane. The data obtained were processed in a statistical software program for a descriptive statistical analysis and for inferential analysis parametric statistical tests by applying the Wilcoxon, chi-square, Student t, and kappa index tests (α=.05).

RESULTS

Statistically significant differences (P<.01) were found between the groups in terms of smile width, smile arc, midline deviation and tilting, and angulation discrepancy between the interpupillary line and the commissural line. Smile arc was the only variable found to be different (P<.01) in relation to sex.

CONCLUSIONS

Characteristics of the most esthetic smiles were no deviation or tilting of the maxillary midline, showing a greater number of teeth in the smile, displaying incisal edges parallel to the lower lip (particularly in women), and displaying occlusal and commissural planes parallel to the interpupillary line.

Symmetry of crown widths in subjects with unilateral maxillary lateral incisor agenesis

PURPOSE

The aim of this study was to compare mesiodistal width and symmetry of maxillary and mandibular teeth in subjects with and without unilateral maxillary lateral incisor agenesis.

PATIENTS AND METHODS

The study group consisted of 31 patients with unilateral maxillary lateral incisor agenesis (19 females, 12 males, mean age: 16.55 ± 5.24 years), and a control group of 31 patients (19 females, 12 males, mean age: 16.58 ± 4.41 years) without agenesis. Mesiodistal dimensions of all teeth except second molars were measured. Paired samples t‑test and Wilcoxon signed-rank test were used for intragroup comparisons. Independent samples t‑test was used for intergroup comparisons.

RESULTS

In the study group, mesiodistal dimensions of maxillary canine, second premolar, first molar, mandibular second premolar and first molar teeth on the agenesis side were significantly smaller than on the contralateral side (p < 0.05). In the control group, no significant difference was seen in mesiodistal dimensions between right and left sides. In the study group, mesiodistal dimensions of all teeth on the lateral agenesis side were significantly smaller than on the control side (p < 0.05). On the side without lateral agenesis, all teeth except the maxillary and mandibular first molars and mandibular second premolar teeth were significantly smaller than on the control side (p < 0.05). Total mesiodistal dimensions of the maxillary teeth were significantly smaller on the lateral agenesis side than on the contralateral side (p = 0.001). Total tooth size of the study group was significantly smaller than for the control group (p < 0.05).

CONCLUSION

Patients with unilateral maxillary lateral incisor agenesis might have asymmetries in tooth width and have smaller teeth than individuals without agenesis.

Surgical Correction of the "Gummy Smile"

The delineation of excessive gingival display and review of current treatment options. Discussion over periodontal and prosthetic treatments, mucosal stripping procedures, myotomies, Botox therapy, and orthognathic procedures for correction of the "gummy smile."

Influence of upper lip curvature on smile attractiveness in patients with different degrees of gingival smiles: A cross-sectional study with opinions from oral health providers and laypersons

INTRODUCTION

Although there is relative consensus about approaches to gingival smile management, there are still discrepancies as to whether a gingival smile is attractive or not. The purpose of this study was to quantify the influence of upper lip curvature shape and the amount of gingival display on the perception of smile attractiveness assessed by Peruvian orthodontists, dentists, and laypersons.

METHODS

A frontal photograph was digitally altered to generate 3 types of upper lip curvature shapes (upward, straight, and downward) with 5 different levels of gingival smile exposure (0 mm, 2 mm, 3 mm, 4 mm, and 5 mm). Fifteen images were generated. Three groups of evaluators (50 dentists, 50 orthodontists, and 50 laypersons) assessed the images using a visual analog scale. One-way analysis of variance with Bonferroni post-hoc tests and multiple linear regressions were applied.

RESULTS

The downward lip curvature shape had a negative effect on the esthetic evaluation of the smile with gingival exposures of 3 mm or more for all the evaluating groups (approximately 20-30 points less than upward or straight smile curvature shapes, P <0.05). Laypeople gave higher scores of almost 10 points more than dentists and orthodontists when evaluating the upward lip curvature shape with 5 mm of gingival exposure during smile (P = 0.029).

CONCLUSIONS

We found that upward or straight upper lip curvature shapes have a positive impact on perceived smile esthetics. In contrast, downward upper lip curvature shapes have a negative effect on perception when evaluating different degrees of gingival smiles.

Composite resin CAD-CAM restorations for a midline diastema closure: A clinical report

A diastema between the maxillary central incisors affects an esthetic smile and has been treated in various ways. Precise diagnosis is essential to guide the choice of the most appropriate treatment. This clinical report describes closing a maxillary midline diastema with a computer-aided design and computer-aided manufacturing (CAD-CAM) composite resin.

Influence of maxillary lateral incisor width ratio on perception of smile esthetics among orthodontists and laypersons

OBJECTIVE

This study aimed to analyze the impact of different maxillary lateral incisor width ratios on the perception of smile esthetics among orthodontists and laypersons.

METHODS

A smile photograph of a male subject showing the lips and gingival margins was selected. The smile was standardized for maxillary central incisor width proportions and ideally perceived smile esthetics. The maxillary lateral incisor width was symmetrically modified in increments of ratios of the central incisor from a ratio of 4:10 to a ratio of 8:10. The images were analyzed by 283 laypersons and 83 orthodontists who ranked the level of attractiveness using a visual analog scale.

RESULTS

There were significant differences between the esthetic perception of the five different width ratios, and between the orthodontists and laypersons in their evaluations of esthetics (P < 0.0004). There were no significant differences in esthetic evaluations between genders.

CONCLUSIONS

For orthodontists, the most attractive width ratio was 5.7:10, while the highest ranked ratio among laypersons was 8:10, although laypersons ranked all ratios very similarly. Both groups ranked the width ratio of 4:10 the lowest. Orthodontists were more critical in their assessment of esthetics.

CLINICAL SIGNIFICANCE

To what proportions or protocol should a peg-shaped maxillary lateral incisor or missing lateral, that is, to be replaced with an implant/crown be restored? This is an important clinical question that is often encountered by the orthodontist and the restoring dentist. The literature suggests that orthodontists and laypeople have different perceptions of smile esthetics, and it is important to have patient centered goals when treatment planning. Further research is necessary to identify the width ratio of which the lateral incisor is perceived to be esthetic as well as the ideal ratio to consider when restoring lateral incisors. This research assessed and compared the perception that orthodontists and laypeople have on smile esthetics regarding different width ratios of lateral incisors.

The Influence of Varying Gingival Display of Maxillary Anterior Teeth on the Perceptions of Smile Aesthetics

OBJECTIVES

The aim of the study was to investigate the influence of gingival display on perceived smile aesthetics and to compare aesthetic gingival display preference amongst dental professionals and lay people.

METHODS

This cross-sectional study was based on the analysis of quantitative data collected via questionnaires. Two sets of digitally altered smile images with variations of gingival amount and architecture displays were produced. Ranking order scale was used to record aesthetic preferences, from the most attractive to the least attractive.

RESULTS

There were 124 respondents (60 lay people, 32 general dentists [GDPs] and 32 orthodontists). Average smile line, tangent to the zeniths of maxillary anterior teeth, was found to be the most attractive gingival amount (53.2%, χ² = 144.15, p < 0.045) amongst lay people, GDPs and orthodontists. High smile line was ranked as the least attractive amount amongst all respondents (88.7%, χ² = 359.37 p < 0.002). Class III gingival outline, where all gingival levels are symmetrical and in line, was found as the most attractive gingival architecture (65.3%, χ² = 10.87 p < 0.001).

CONCLUSION

No particular amount of gingival display is universally perceived as attractive although high smile lines are generally disliked. Class III gingival architecture is the most preferred gingival archetype when excessive amount of maxillary gingiva is exposed.

CLINICAL SIGNIFICANCE

A general acceptance to smile line variations demonstrates that the harmony amongst all smile components is more important than merely focusing on a single ideal smile constituent. However, when designing the smile with an inherent high lip line, a Class III gingival architecture might be more preferable since it reduces the negative impact of excessive gingival display.

The perceptions of preclinical and clinical dental students to altered smile aesthetics

Introduction

This prospective cohort study was designed to identify which components of a smile make it more or less aesthetically acceptable to dental students.

Aim

To investigate whether students at different stages of their undergraduate dental education held similar views on smile aesthetics. Additionally, to see whether students from the same ethnicity were more likely to have similar perceptions of smile aesthetics than students from different backgrounds.

Methodology

Dental students in either Year 1 (preclinical) or Year 5 (clinical) of their studies at the University of Bristol were asked to complete a questionnaire. Students were asked to rank 12 photographic images in order from most aesthetically pleasing (1) to least pleasing (12). The 12 images included one ‘ideal’ smile and 11 digitally altered images of the same “ideal” smile.

Results

A total of 123 questionnaires were completed. Clinical students were more likely to rank the ‘ideal smile’ as more aesthetically pleasing and identify it as the “best” smile from the set of images. Preclinical students considered retroclined incisors to be significantly less pleasing than clinical year students, whilst clinical year students found a midline diastema significantly less pleasing than preclinical students.

Conclusions

Dental students at different stages of their undergraduate dental education have different perceptions of smile aesthetics. There was no evidence that the perception of dental attractiveness was affected by students’ ethnicities or location of upbringing.

A Communication Guide for Orthodontic-Restorative Collaborations: An Orthodontic Perspective on the Importance of Working in a Team

As both restorative dentists and specialists have their respective realms of expertise, it is important to develop a team of qualified providers to improve treatment outcomes for patients. In many cases, this involves collaboration between a restorative dentist and orthodontist. Effective communication is critical, with the dentist's understanding of basic orthodontic terminology and case planning considerations. Recognizing the context in which to apply normative occlusal and cephalometric values often necessitates comprehensive specialty-level experience. All providers should recognize when to involve the indicated team members when complex multidisciplinary treatment needs are present. The team approach offers an opportunity to optimize excellent patient care.