Factors associated with the beauty of soft-tissue profile

Introduction: Factors affecting the attractiveness of soft-tissue profile have been assessed in only a few studies, with limited methodologies (such as few variables, small sample sizes) and bivariable analyses. Therefore, this study was conducted to elucidate esthetic factors of profile silhouettes among a long list of cephalometric variables with the use of multivariable analyses for the first time. Methods: Profile silhouettes of 70 Iranians (35 men and 35 women) with Class I/good occlusions and balanced faces were rated twice by 10 Iranian laypersons, and were given overall profile beauty scores (from 10 to 50). After careful landmark identification by 3 orthodontists, unrepeated cephalometric measurements (from Holdaway, Ricketts, Z-Merrifield, Epker, and Legan-Burstone analyses) were traced twice on all cephalographs. The effects of these variables (plus sex and age) on profile beauty scores were assessed with the use of Pearson coefficient and multiple linear regression. Cephalometric characteristics of Persian attractive profiles (scores from 40 to 50) were compared with Caucasian orthodontic norms (alpha = 0.05). Results: The following variables were significant in the best models: soft-tissue facial angle (beta = -0.348, P = 0.016), nose prominence (beta = -0.245; P = 0.044), skeletal profile convexity (beta = 0.255; P = 0.052), upper lip curvature (beta= 0.405; P = 0.042), nasolabial angle (beta = 0.546; P = 0.000), nasofacial angle (beta = 0.259; P = 0.028), Z-angle (beta = 0.557; P = 0.015), H-angle (beta = -0.360; P = 0.013), upper lip to E-plane (beta = 0.691; P = 0.001), lower lip to E-plane (beta = -0.674; P = 0.002), Sn-lower lip (beta = 0.338; P = 0.055), lower lip-menton (beta = -0.299; P = 0.025), Sn FH-perp to upper lip (beta = -0.425; P = 0.001), Sn-Stms:Stms-Me' (beta = -0.372; P = 0.016), facial convexity angle (beta = 0.710; P = 0.000), lower lip protrusion (beta = -0.342; P = 0.005), and interlabial gap (beta = -0.179; P = 0.050). Sex and age were not associated with profile attractiveness (P > 0.75). More convex skeletal and soft-tissue profiles, less prominent noses with higher tips, subnasales anterior to the upper lip, more protruded upper lips, less prominent lower lips, smaller interlabial gaps, and more protruding chins might improve profile esthetics.