Smile esthetics represents an important component of facial appearance and may influence self-confidence, social interaction, and psychological well-being.¹ The alignment, position, shape, and visibility of the teeth contribute substantially to the overall perception of a smile.² Consequently, abnormalities such as crowding, spacing, increased overjet, open bite, and irregularity of the anterior teeth may influence an individual's perception of dental attractiveness.¹

Malocclusion is traditionally evaluated using objective clinical measures that quantify the presence and severity of occlusal abnormalities.³ Such indices are useful for epidemiological assessment, comparison between populations, and estimation of orthodontic treatment need.⁴ However, the numerical severity of malocclusion does not necessarily correspond directly to the patient's perception of their own dental appearance.¹ The perception of dental esthetics is subjective and may be influenced by age, sex, cultural background, socioeconomic characteristics, previous orthodontic experience, psychological factors, and individual expectations. Thus, individuals with apparently similar occlusal conditions may demonstrate substantially different levels of satisfaction with their smiles.⁵

The Dental Aesthetic Index (DAI) is one of the commonly used standardized indices for assessing dental appearance and malocclusion severity. It incorporates several occlusal and aesthetic characteristics into a single numerical score and categorizes individuals according to the severity of their malocclusion.⁶ Previous research has demonstrated that malocclusion may have psychosocial consequences and may negatively influence oral-health-related quality of life. However, the relationship between objectively assessed malocclusion and subjective perception is not necessarily linear. Some individuals with objectively significant malocclusion may report relatively little dissatisfaction, whereas others with relatively minor irregularities may perceive considerable aesthetic impairment.⁷ This distinction is particularly relevant in orthodontic practice. Treatment planning should not rely exclusively on an objective index; rather, the patient's concerns, expectations, perceived aesthetic problem, and treatment goals should also be considered.⁸

The present study was therefore designed to investigate the association between objectively assessed malocclusion severity and self-perceived smile esthetics among adults.

Study design: A cross-sectional analytical study design was used. The study was structured according to the general reporting principles recommended for observational cross-sectional research. Study setting: The study was conducted in the Department of Orthodontics of a dental teaching hospital in Pakistan after obtaining the ethical approval vide # 1371-ERC/AMCS. The data-collection period was January 2026 to June 2026. Study population: The study population consisted of adults aged 18–50 years attending the dental outpatient department. Inclusion criteria Participants were considered eligible if they: • were 18 years of age or older; • had erupted permanent anterior teeth sufficient for aesthetic assessment; • were able to understand the questionnaire; • provided informed consent; and • were willing to undergo clinical assessment. Exclusion criteria Participants were excluded if they: • were currently undergoing active orthodontic treatment; • had extensive anterior restorations that substantially altered dental appearance; • had extensive loss of anterior teeth; • had craniofacial syndromes or congenital anomalies affecting occlusion; • had severe dental disease preventing adequate assessment; or • were unable to complete the questionnaire. Sample size A sample size of 240 participants was selected to provide an adequate number of observations across the different malocclusion-severity categories and permit multivariable statistical analysis. Sampling technique A consecutive sampling technique was used. Eligible adults attending the study setting during the study period were considered for inclusion until the predetermined sample size was reached. Data collection instrument A structured data-collection proforma was used. It consisted of three sections: 1. Sociodemographic information; 2. Clinical assessment of malocclusion; and 3. Self-perceived smile-esthetic assessment. Assessment of malocclusion Malocclusion severity was assessed using the Dental Aesthetic Index (DAI). The DAI incorporates ten occlusal and aesthetic characteristics, including: • missing visible teeth; • crowding; • spacing; • midline diastema; • anterior maxillary irregularity; • anterior mandibular irregularity; • anterior maxillary overjet; • anterior mandibular overjet; • vertical anterior open bite; and • anteroposterior molar relationship. The weighted DAI score was calculated according to the standard scoring system. Participants were classified into four categories: DAI score Interpretation ≤25 Normal/minor malocclusion 26–30 Definite malocclusion 31–35 Severe malocclusion ≥36 Very severe/handicapping malocclusion Assessment of self-perceived smile esthetics Self-perceived smile esthetics was assessed using a five-point rating scale. Participants were asked to rate their satisfaction with the appearance of their smile. The response categories were: 1. Very satisfied 2. Satisfied 3. Neutral 4. Dissatisfied 5. Very dissatisfied For statistical analysis, the score was treated as an ordinal/approximately continuous outcome, with higher scores indicating greater dissatisfaction. Statistical analysis Data have been analyzed using IBM SPSS Statistics version 28. Continuous variables were summarized using mean and standard deviation, while categorical variables were summarized using frequencies and percentages. The distribution of the self-perceived esthetic score was assessed before selection of inferential tests. Because the self-perceived esthetic score was ordinal, the Kruskal-Wallis test was used to compare scores among the four DAI categories. Spearman's rank correlation coefficient was used to determine the relationship between DAI score and self-perceived esthetic dissatisfaction. A multivariable linear regression model was additionally used to examine whether DAI score remained independently associated with the esthetic score after adjustment for age, sex, and previous orthodontic treatment. Statistical significance was set at p < 0.05.

A total of 240 participants were included  The mean age was 30.9 ± 8.6 years, with participants ranging from 18 to 50 years. There were 108 (45.0%) males and 132 (55.0%) females. Thirty-eight participants (15.8%) reported previous orthodontic treatment, whereas 202 (84.2%) had no history of orthodontic treatment.

Table 1. Sociodemographic and orthodontic characteristics of participants

The mean DAI score in the was 29.6 ± 8.3. Of the 240 participants, 77 (32.1%) had normal/minor malocclusion, 64 (26.7%) had definite malocclusion, 46 (19.2%) had severe malocclusion, and 53 (22.1%) had very severe malocclusion.

Table 2. Distribution of participants according to DAI category

The mean self-perceived esthetic dissatisfaction score was 2.52 ± 0.70. Many participants reported either satisfactory or neutral perceptions of their smiles, while a smaller proportion reported substantial dissatisfaction.

Table 3. Distribution of participants according to self-perceived smile esthetics

A progressive increase in mean esthetic dissatisfaction was observed with increasing malocclusion severity. Participants with normal/minor malocclusion had a mean score of 1.97 ± 0.63, compared with 2.47 ± 0.60 among those with definite malocclusion, 2.73 ± 0.59 among those with severe malocclusion, and 3.14 ± 0.68 among those with very severe malocclusion. The difference between the four groups was statistically significant (Kruskal-Wallis H = 78.78, p < 0.001).

Table 4. Self-perceived esthetic dissatisfaction according to DAI category

A significant positive correlation was identified between DAI score and self-perceived esthetic dissatisfaction. Spearman's correlation analysis demonstrated a moderate positive correlation (ρ = 0.599, p < 0.001). This indicated that participants with higher DAI scores generally reported greater dissatisfaction with the appearance of their smiles.

Table 5. Correlation between malocclusion severity and self-perceived esthetic dissatisfaction

A multivariable linear regression model was constructed with self-perceived esthetic dissatisfaction as the dependent variable. The model explained approximately 36.7% of the variance in esthetic dissatisfaction (R² = 0.367; adjusted R² = 0.356). DAI score remained a significant independent predictor of esthetic dissatisfaction after adjustment for age, sex, and previous orthodontic treatment. For each one-point increase in DAI score, the esthetic dissatisfaction score increased by approximately 0.057 points (β = 0.057, 95% CI: 0.047–0.066, p < 0.001).

Table 6. Multivariable linear regression analysis of factors associated with self-perceived esthetic dissatisfaction

*Reference categories: female sex and no previous orthodontic treatment.

Model R² = 0.367; adjusted R² = 0.356; p < 0.001.

The present study investigated whether objectively assessed malocclusion severity was associated with self-perceived smile-esthetic dissatisfaction among adults. The principal finding was a statistically significant positive association between DAI score and esthetic dissatisfaction. Participants with progressively more severe malocclusion reported progressively greater dissatisfaction with their smiles. The mean esthetic dissatisfaction score increased from 1.97 among participants with normal/minor malocclusion to 3.14 among those with very severe malocclusion. Furthermore, the correlation analysis demonstrated a moderate positive association between DAI score and esthetic dissatisfaction. The observed association is clinically plausible because several components included in the DAI directly influence the visible appearance of the dentition. Crowding, spacing, anterior irregularity, excessive overjet, and open bite can alter smile appearance and may therefore be recognized by individuals themselves.9 Nevertheless, the correlation was not perfect. This is an important finding because self-perceived smile esthetics is inherently subjective. If DAI score and self-perception were completely equivalent, an almost perfect correlation would be expected. Instead, the moderate correlation observed in this dataset suggests that other factors may contribute to an individual's perception of their smile.10 Psychological and social factors may influence perceptions of dental attractiveness. Individuals may differ in their expectations regarding an ideal smile, their awareness of dental irregularities, and the importance they assign to physical appearance.11 Cultural norms and exposure to idealized facial images through conventional and social media may also influence aesthetic expectations.12 Previous orthodontic experience may represent another potential influence. Individuals who have previously undergone orthodontic treatment may have different expectations regarding dental alignment and may be more aware of residual irregularities.13-15 However, previous orthodontic treatment was not independently associated with esthetic dissatisfaction in the present regression model. Sex was also not independently associated with esthetic dissatisfaction after adjustment for DAI score and other variables. This suggests that, within this dataset, the clinical severity of malocclusion was a stronger predictor of perceived dissatisfaction than sex.14 The multivariable analysis further strengthened the primary finding. DAI score remained significantly associated with esthetic dissatisfaction after adjustment for age, sex, and previous orthodontic treatment. The model explained approximately 36.7% of the variance in the outcome, indicating that malocclusion severity represents an important, but not exclusive, determinant of self-perceived smile esthetics. Limitations Several limitations should be acknowledged. First, the cross-sectional design does not permit determination of causality. Although greater malocclusion severity was associated with greater esthetic dissatisfaction, the direction of the relationship cannot be established from cross-sectional data. Secondly, self-perceived smile esthetics is subjective and may be influenced by psychological, social, and cultural factors.

In this cross-sectional, greater malocclusion severity was significantly associated with greater self-perceived smile-esthetic dissatisfaction among adults. The progressive increase in dissatisfaction across DAI categories and the moderate positive correlation between DAI score and subjective dissatisfaction suggest that objective malocclusion severity is an important determinant of perceived dental appearance. However, the association was not perfect, indicating that subjective perception is influenced by factors beyond clinical malocclusion severity.

Therefore, orthodontic assessment should incorporate both standardized clinical indices and patient-reported perceptions of dental appearance.