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

Effect of Midline Deviation and Crown Width Disproportion on Perception of Smile Esthetics

OBJECTIVES

To evaluate the effect of maxillary midline deviation and crown width disproportion on the perception of smile attractiveness through full-face images among dentists and laypeople.

METHODS AND MATERIALS

A full portrait image of a smiling 25-year-old female, exhibiting good dental alignment, midline position, and tooth size symmetry, was selected as a model for the present study. The original image was digitally modified using photo editing software (Photoshop CC, Version 25.12.0; Adobe) to simulate three different case scenarios of varying levels: Midline deviation (1-4 mm), single crown width disproportion, separately for central incisor, lateral incisor, and canine (1 and 2 mm), and crown width disproportions distributed to anterior teeth (1-4 mm). In total, 15 modified images were displayed randomly to 180 observers (90 laypeople and 90 dentists) including the original image that served as a control. Each observer scored the level of smile esthetics for each image using a visual analog scale ranging from point 0 (unattractive) to 100 (attractive). Bonferroni Test and Partial Eta Squared were utilized for the statistical data analyses (α < 0.05).

RESULTS

Attractiveness scores were significantly lower for the modified smiles with the single crown width disproportion than distributed crown width disproportion and midline deviation (p < 0.001 for each), of which two presented statistically similar attractiveness (p = 0.278). The highest attractiveness scores were obtained for the control image (90.35 ± 5.56A), midline deviation of 1 mm (88.89 ± 5.93AB), 2 mm (86.80 ± 6.70ABC), and distributed disproportion of crown width of 1 mm (87.75 ± 6.70AB). A single central incisor disproportion of 2 mm (45.51 ± 11.94I) was perceived significantly less attractive, followed by a midline deviation of 4 mm (57.51 ± 12.58H) and a distributed disproportion of crown width of 4 mm (59.11 ± 9.72H). Modified images were perceived as significantly more attractive by laypeople and male observers compared to dentists and female observers (p < 0.001 for each). Older observers between 35 and 50 years old scored significantly higher than younger observers (p = 0.001).

CONCLUSIONS

Dentofacial midline discrepancy had less effect on smile attractiveness compared to crown width disproportions. Midline deviations up to 2 mm were not noticeable for both laypeople and dentists. The deviations of 3 mm were noticeable but still more attractive than the deviations of 4 mm, which were considered the least attractive. A single crown width disproportion was less perceived when moving from the central incisor toward the canine. Distributing the crown width disproportions among anterior teeth can be beneficial for smile attractiveness compared to non-distributed cases.

CLINICAL SIGNIFICANCE

Generating symmetrical crown width proportions of the anterior teeth seems more important for smile esthetics than dentofacial midline harmony. Distribution of crown width disproportions among the anterior teeth can enhance smile esthetics.

Treatment Options for Unilateral Agenesis of the Maxillary Lateral Incisor Combined with Contralateral Microdontic or Peg-Shaped Lateral Incisor: A Systematic Review

Background: Managing unilateral maxillary lateral incisor agenesis (UMLIA) with an associated microdontic or peg-shaped contralateral incisor (Mi or Peg MLI) presents clinical and esthetic challenges. Deciding between orthodontic space opening (OSO) or closure (OSC) and whether to restore or extract the Mi or Peg MLI are critical factors for achieving optimal treatment outcomes. Methods: A systematic review was conducted using a dual strategy across Scopus, Web of Science, Embase, PubMed, and Cochrane Central Register of Controlled Trials databases. The Cochrane RoB2 tool was used for randomized controlled trials (RCTs), the ACROBAT-NRSI tool for non-randomized studies, and the JBI Manual for case reports. High-quality case reports were included when the literature was limited. The GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) tool evaluated the certainty of evidence, considering bias, inconsistency, indirectness, imprecision and other considerations. Results: Thirty-five studies met the inclusion criteria, assessing treatment modalities, esthetic outcomes, periodontal health, and occlusal and temporomandibular joint (TMJ) function. Both OSO and OSC demonstrated similar occlusal and TMJ outcomes, while slight differences in esthetic and periodontal results were noted between the two approaches. Direct composite and indirect ceramic restorations showed comparable effectiveness for reshaping the Mi or Peg MLI. Extraction combined with OSC contributed to improved smile symmetry. Conclusions: A personalized, multidisciplinary approach is essential for treating UMLIA with an Mi or Peg MLI. Both OSO and OSC are viable options, and the choice should be tailored to the patient's specific clinical scenario, with attention to achieving the best esthetic and periodontal outcomes. Further research is needed to refine treatment protocols and support clinical decision-making.

Corrections of Dental Anomalies in the Maxillary Incisors and Their Influence on Perceived Smile Esthetics: A Systematic Review

INTRODUCTION

Dental anomalies present a significant challenge to clinicians due to their impact on both dental function and esthetics. The correction of these anomalies plays a critical role in improving the quality of life of our patients, highlighting the importance of this restorative work.

OBJECTIVE

The purpose of this systematic review is to assess the techniques used to restore various dental anomalies, and their subsequent esthetic impact on the overall dentition.

METHODS

Inclusion criteria consisted of restorative rehabilitations of the permanent dentition in non-syndromic patients with dental anomalies of morphology, structure, size, and number in the maxillary incisors. Exclusion criteria included surgical rehabilitation techniques, endodontic treatments, and anomalies of the primary dentition. The medical literature was systematically searched (Pubmed, PMC, Embase, Cochrane Central Register of Controlled Clinical trials, Scopus and Google Scholar) to identify all relevant articles reporting data regarding the chosen anomalies. ROBINS-I was used to assess the risk of bias tool, and the results were tabulate due to data heterogeneity.

RESULTS

Of the 1821 analyzed articles, 46 articles met the inclusion criteria, and were chosen to go through the final review procedure. Of the selected articles, 3 investigated amelogenesis imperfecta and dentinogenesis imperfecta, 1 analyzed conoid teeth, 1 considered hypodontia (other than MLIA), 3 concerned microdontia (excluding peg laterals and conoid teeth), 10 evaluated peg-shaped laterals, 2 investigated talon cusps and geminated teeth, 15 were regarding maxillary lateral incisor agenesis, and 11 papers were related to the perception of anomalies.

CONCLUSIONS

Pre-visualization using Digital Smile Design, a treatment plan encompassing minimally invasive restorations, and using a multidisciplinary approach among practitioners helps the anomalous patient achieve the best possible esthetic result.

The normal width of the lateral incisors in the maxilla in an European population

OBJECTIVES

Dental anomalies are clinical alterations that originate during the tooth formation process. This prospective study aims to establish the norm and hypoplasia values for maxillary lateral incisors. Additionally, it aims to describe the relationship between the width of the lateral and the central incisors, considering gender, age, and body height.

MATERIALS AND METHODS

The first 103 consecutive patients meeting the inclusion criteria were included in the study. The upper jaw of each patient was scanned, and the scans were saved as standard tessellation language (STL) files. The upper incisors of each digital cast were measured on the computer. Two examiners performed the same measurements independently.

RESULTS

The average size of the maxillary central incisor was 8.59 ± 0.51 mm, while the average size of the maxillary lateral incisor was 6.64 ± 0.46 mm. A formula describing a relationship between the central (x) and lateral (y) incisors was defined with a linear regression analysis y = 1.88 + 0.55 * x. Width of maxillary incisors [11, 12, 21, 22] increased with height (p = 0.028, p = 0.016, p = 0.016, p = 0.046 respectively).

CONCLUSIONS

Hypoplasia of the maxillary lateral incisor can be defined for teeth with a mesiodistal width less than 6.18 mm in a patient that is represented with the test group. A relationship between the maxillary lateral incisors and central incisors could have been established by means of a formula.

CLINICAL RELEVANCE

The width of the maxillary lateral incisors allows a precise orthodontic and prosthetic planning.

Impact of long contact areas for the management of varying levels of interdental papilla loss on the perception of smile esthetics between dentists and laypersons in asymmetric and symmetric situations

PURPOSE

To determine the effect of restorations with long contact areas for the management of interdental papilla deficiencies, in smile attractiveness among laypersons and dentists.

MATERIAL AND METHODS

A full-portrait image was used to create a set of digitally modified images, simulating the management of various levels of interdental papilla loss. In a total of 48 modified images, single as well as multiple loss of interdental papilla among the anterior teeth, treated with a single or multiple restorations were simulated for unilateral and bilateral situations. Through a digital monitor 160 laypeople and dentists were asked to assess the attractiveness of each displayed image utilizing a visual-analog-scale. Multiple Wilcoxon-signed-rank tests followed by Mann-Whitney U tests were performed considering a significance level of 0.05.

RESULTS

The management of an open gingival embrasure due to interdental papilla loss, by simulating the restoration of both central incisors led to a significantly higher mean smile attractiveness compared to the restoration of a single central incisor. Among the investigated regions, the management of open gingival embrasure in the area of central incisors using a restorative approach was perceived as the least esthetic (p < 0.05).

CONCLUSIONS

Despite the restorative management of interdental papilla loss, with the establishment of longer contact areas for the reduction of open gingival embrasures, as the level of the interdental papilla loss is increased, facial esthetics are compromised. When a longer contact area is accomplished through a single restoration, asymmetry among the teeth can be induced, especially in the region of the central incisors.

Esthetic Perception of Different Clinical Situations of Maxillary Lateral Incisor Agenesis According to Populations with Dental and Non-Dental Backgrounds: A Systematic Review and Meta-Analysis

Treatment of unilateral or bilateral maxillary lateral incisor agenesis is challenging, time-consuming, expensive, and requires careful treatment planning, predictability, and esthetics. This review aimed to identify differences in esthetic perception among orthodontists, general dentists, differentiated dentists, and laypersons, which may interfere with treatment options. EBSCO, PubMed, ScienceDirect, Cochrane Library databases, and Google Scholar were searched using keyword pairing and a Boolean expression, "(congenitally missing OR agenesis OR hypodontia) AND (maxillary lateral incisors) AND (esthetic perception OR smile) AND (laypersons OR dental professional OR general dentist OR orthodontists)." Reviews and case studies were excluded. A total of 13 studies were selected for qualitative analysis (adapted ROBINS-I) and 11 were selected for meta-analysis (p < 0.05) after being sub-grouped into "Opening vs. Closure" and "No remodeling vs. Dental remodeling vs. Dental and gingival remodeling" groups. A meta-analysis evaluated the magnitude of the difference between groups based on differences in means and effect sizes (α = 0.05; 95% CI; Z-value 1.96), revealing that the esthetic perception of maxillary lateral incisor agenesis treatment remains controversial even among professionals. Gingival remodeling was not valued compared to isolated dental remodeling. Studies lack rigorously comparable methodologies. Discussion with the patient is pertinent in doubtful situations, as the best treatment option remains unclear, and overtreatment should be avoided.

Effect of smile esthetics on the quality of life in a Han Chinese population

OBJECTIVE

This study aimed to explore the influence of smile esthetics on the quality of life in a Han Chinese population.

METHODS

A total of 110 Han Chinese volunteers (52 males and 58 females, mean age 26.7 years) were recruited, and frontal images of their smiles were collected. A photoediting program was used to evaluate the following components of smile esthetics: the buccal corridor ratios, the angle between the interpupillary and commissural lines, the number of visible teeth, and width-to-length ratios of the maxillary central incisors. Oral health-related quality of life (OHRQoL) in these volunteers was evaluated using the Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ) and Oral Health Impact Profile-14 (OHIP-14). Statistical analyses were performed by using Pearson's correlations and multiple linear regression (α = 0.05).

RESULTS

Compared to males, females scored higher on psychological impact (p = 0.017). Moreover, the number of visible teeth had a significant effect on social impact, psychological impact and esthetic concern (all p < 0.05). However, the buccal corridor ratios, the angle between the interpupillary and commissural lines, and the width-to-length ratios of the maxillary central incisor did not correlate with the OHRQoL (all p > 0.05).

CONCLUSIONS

The number of visible teeth significantly influenced the quality of life in a Han Chinese population. Smile esthetics had a significantly greater psychological impact on females than males.

CLINICAL SIGNIFICANCE

This study highlights the effects of smile esthetics on the quality of life in a Han Chinese population. Female patients may raise more esthetic concerns in clinical practice.

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.