Tooth emergence in Australian Aboriginals.

Patterns of dental development in 125 Australian Aboriginal boys and girls, in a growth study at Yuendumu in the Northern Territory of Australia, were compared with Australians of European origin using mean tooth emergence curves constructed from the emergence times of right and left side permanent teeth. There were two active phases of tooth emergence separated by a quiescent period of 1.4 years in boys and 1.0 years in girls. Phase one included emergence of the first 12 teeth, that is the first permanent molars and all incisors; phase two included emergence of the canines, premolars and second molars. In Aboriginal girls most teeth emerged earlier than in boys. Compared with the European-descended, the Aboriginal children displayed earlier emergence of most teeth during phase two and a shorter quiescent period between the two phases, an emergence pattern similar to that reported in other non-European populations. In Aboriginals the process tooth emergence and subsequent alignment is aided by adequate space and compensatory bone growth growth in the alveolar regions. These factors, as well as the genetic differences between groups, contribute to the earlier emergence of teeth during phase two in the Aboriginal children.