Normative smile esthetic characteristics and sexual dimorphism in young Yemeni adults: a digital photographic analysis

Smile esthetics significantly influence facial attractiveness and are essential for esthetic dental treatment planning. As smile characteristics vary among populations, establishing population-specific normative data is important, particularly for underrepresented groups such as Yemeni adults. This cross-sectional study evaluated smile esthetic characteristics and sexual dimorphism in 119 healthy Yemeni adults (60 males and 59 females) aged 17–30 years using standardized digital photography. The assessed parameters included smile arc, gingival display, lip line, number of visible teeth during smiling, and maxillary incisor display at rest and during smiling, analyzed using Exocad DentalCAD and Adobe Photoshop software. The consonant smile arc was the predominant pattern, observed in 77.3% of participants. Class III gingival display, visibility extending to the second premolars, and average-to-high lip lines were the most frequent characteristics. Females showed a significantly higher prevalence of consonant smile arcs than males ( P < 0.05), while no significant sex differences were observed for gingival display, lip line, number of displayed teeth, or maxillary incisor display. Maxillary incisor display significantly increased during smiling and was significantly associated with smile arc morphology. These findings provide valuable normative data for young Yemeni adults and may enhance esthetic diagnosis, digital smile design, and personalized interdisciplinary treatment planning.