Influence of Nasolabial Angle on Facial and Smile Attractiveness.

Objective: To identify the effect of the nasolabial angle (NL) on smile and facial profile attractiveness.

Study design: A cross-sectional study. Place and Duration of the Study: Department of Surgery, Section of Dentistry (Orthodontics), The Aga Khan University Hospital, Karachi, Pakistan, from 31 November 2021 to 28 March 2022.

Methodology: Profile photographs of one adult male and one female subject at rest and on smile were altered by the Photoshop software to NL angles of (85°, 90°, 95°, 100°, 105°, and 110°). These photographs were shown to a panel of raters comprising of three groups, laypersons (LP), general dentists (GD), and orthodontists (OD). The Kruskal-Wallis test was used to compare the NL angle scores among raters. Mann-Whitney U test was used for pairwise comparison between groups and gender-wise comparison of raters. Wilcoxon signed-rank test was used to analyse the effect of smile on the NL angle.

Results: Statistically significant differences (p ≤0.05) were seen between rest and smile scores in three groups of raters. LP gave the highest scores to 95° for males (p <0.001) and females (p = 0.011). GD found 90° for both males (p = 0.009) and females (p = 0.014) to be attractive, while OD gave the highest scores to 95° for both males (p <0.001) and females (p = 0.002).

Conclusion: There was a significant difference in preference of nasolabial angle between male and female raters. All groups of raters gave the highest scores to smiling photographs. The clinical significance is to ensure that, upon completion of orthodontic treatment, the nasolabial angle should be finished in a manner that enhances rather than detracts the attractiveness of the smile.

Key words: Nasolabial angle, Smile, Facial aesthetics, Profile photographs.