Variation in the convexity of the human maxillary incisor labial surface.

Labial surface convexity of the maxillary central incisors ( ILC ) is classified with a new five grade ranked scale. More than 2,000 individuals representing 20 worldwide populations were studied. Principle findings are 1) sexual dimorphism is not significant, 2) antimere asymmetry is moderate, 3) labial convexity is negatively associated (r = -0.48) with labial surface double- shovelling , and 4) significant differences occur between several populations. Convexity is most marked in African and Asiatic Indian populations, particularly Bushmen . Europeans have intermediate degrees of convexity, and American Indians the least; Eskimos have the highest amount of convexity among Native Americans. Pacific Islanders are intermediate; Melanesians show the strongest expression of incisor labial convexity in the Pacific.