Soft-Tissue Anthropometric Norms of Iranians with Proper Occlusion and Inter-Ethnic Norm Comparisons

Abstract

Background Photographic soft-tissue norms of Iranian race are not reported previously, nor are they compared with other ethnicities. Besides, sex dimorphism is assessed in only very few studies on soft-tissue profile. The aim of this study was to assess the soft-tissue measurements of Iranians with good occlusion and the existing sex dimorphism and to compare the Iranian norms with other ethnicities. Materials and Methods Twelve anthropometric variables were measured by a dentist in 100 Iranian subjects with good occlusions. The subjects included 50 males and 50 females. The differences between the two genders, as well as the differences between Iranian norms and the norms in all other ethnicities available in the literature were statistically analyzed using a t test (a = 0.05). Results There were significant differences between males and females regarding frontonasal angle (P = 0.0000), mentolabial sulcus (P = 0.0000), vertical height ratio (P = 0.0000), vertical lip-chin ratio (P = 0.0013), nasolabial angle (P = 0.0019), lower vertical height-depth ratio (P = 0.0029), maxillary prognathism (P = 0.0045), and mandibular prognathism (P = 0.0118). The difference in facial convexity was marginally significant (P = 0.0543). Protrusions of both lips and horizontal distance between the lips were not significantly different between sexes (P [ 0.2). Conclusions Unlike Americans and Brazilians but similar to Koreans, there was considerable sex dimorphism in Iranians. Compared to Iranian men, women might have more convex profiles, more advanced mandibles (unlike all other races studied), more protruded maxillae, lips closer to the middle of nose-chin vertical distance, deeper mentolabial sulci, less protruded noses with higher nose tips, and smaller lower faces.