ABSTRACT
Objective The facial soft tissue features were studied in Urumqi adolescent with skeletal Ⅱ malocclusion by using a polar coordinate system. Methods Sixty samples of Urumqi adolescent with skeletal Ⅱ malocclusion were selected, each one underwent cephalometrics analysis and 32 cephalometric parameters from the samples were measured. The mean and standard deviations of each measurement were compared by statistical analysis (t-test). Results Polar distance in male was larger than female, showing significant difference between male and female. Po-Ns/Po-Li, Po-Ns/Po-Bs, Po-Ns/PoPgs, Po-Ns/Po-Gns, and Po-Ns/Po-Mes showed significant difference between male and female. Polar angles in female were larger than male, with a significant difference between male and female.Conclusion Statisticalstudies on features of facial soft tissue show significant differences between male and female. The polar coordinate analysis system is a good index to study the growth magnititude and direction of facial soft tissue during growth and development or before treatment and after treatment.