The growth trends of Korean adolescents with bialveolar protrusion: a nine year longitudinal cephalometric study.

Bialveolar protrusion and dental crowding seems to have common features in terms of aetiology and treatment method, although they result in different facial profiles and tooth alignment. The aim of this longitudinal study is to determine when children begin to show bialveolar protrusive traits in order to get more clue about the aetiology of bialveolar protrusion. Longitudinal lateral cephalometric data of children followed from 6 to 14 years of age were used. A total of 155 children (81 girls and 74 boys) with showing Class molar relationships at the age of 14 were assigned to either the protrusive group (PG) or the non-protrusive group (NPG), based on 5 cephalometric measurements. The cephalometric measurements of these 2 groups were compared at each age separately in both sexes by independent t-tests. Throughout the entire observation period, there were differences between PG and NPG in both sexes in measurements which were used for classification at 14 years of age. There were differences between sexes in both PG and NPG in several measurements of at several different ages. Individuals with bialveolar protrusive traits at the age of 14 exhibited the signs early in life, at least from the early mixed dentition.