Assessment of Smile Index Variation Across Different Malocclusions

Aim: The smile index is a valuable characteristic for comparing smiles between individuals or tracking changes over time in the same person. This study aimed to assess the smile index in untreated patients with different types of malocclusions.
Materials and Methods: The study included 60 participants (25 males, 35 females) aged 16 to 35 years, categorized into three groups of 20 participants each, based on the type of malocclusion. Standardized extraoral photographs with a posed smile were taken, and photogrammetric analysis was performed using specialized image analysis software to determine the smile index for each participant. Statistical analysis was conducted using SPSS version 26.0.
Results:The overall mean value was 7.05 ± 2.26mm. For p >0.05, no significant differences were observed between the three classes of malocclusion. The highest average smile index value was observed in Class I (7.44 ± 3.27mm), while the lowest was in Class III (6.83 ± 1.51mm), with F=0.441, df =2, and p=0.646. The smile index for Class II was 6.89 ±1.64mm. The index was significantly higher in males compared to females in Class I (t(18)= 3.275, p= 0.004). In Class II, the difference was not statistically significant, with females showing a slightly higher value (t(18)= 0.710, p= 0.487), and in Class III, no significant difference was observed (t(18) = 0.041, p= 0.968).
Conclusion: Orthodontists should consider smile aesthetics during diagnosis, treatment planning, and the selection of treatment methods before initiating orthodontic therapy.
Keywords: index, mini-esthetics, smile.