[Three-dimensional measurement of the maxillary first molar in Australian whites]

The occlusal surfaces of upper first molars of Australian Whites were measured in three dimensions with the aid of moiré contourography. The dental casts had been collected from Australian White twins who were considered to be of European stock and the casts housed in the Department of Dentistry, The University of Adelaide, South Australia. In the present study, our first aim was to describe the three-dimensional features of occlusal surfaces of molars in Australian whites. One cast was selected from each monozygotic twin pair at random. A total of 24 males and 15 females were photographed. The results obtained in the present study were compared with those of other human populations previously reported. Cusp height of Australian Whites showed intermediate mean values among 8 populations, but mean intercuspal distances were smaller. This feature, such as small size of occlusal surface but relatively high cusps, also found in Dutch and Asiatic Indian. Mean cusp heights in this population of showed similar values between sexes. Mean differences were insignificant as in Asiatic Indian, Australian Aboriginals, and Bantu unlike the Mongoloid, Japanese and Eskimo populations, where there were significant sex differences in cusp heights. This sexual dimorphism in cusp height among human populations is discussed phylogenetically and functionally.