Skeletal and dental arch asymmetries in Class II division 1 subdivision malocclusions.

The aim of this study is to determine whether or not skeletal and/or dental asymmetries were presented in patients with Class II division 1 subdivision malocclusions. Frontal cephalometric radiographs and dental arch casts were obtained from thirty Brazilians from Rio de Janeiro; the mean age of the sample was 11.6 years. Nine bilateral triangles were established on tracings of the radiographs to describe the cranio-dento-facial complex. The area of each triangle was calculated, and the frequency of AP and transverse asymmetries on the dental casts were determined. When comparing Class I and Class II sides on the radiographs, Student t-tests did not show any statistically significant differences in triangle areas. However, the frequency of asymmetries on the dental casts were statistically significant at the 1% level. These asymmetries were more evident in the anteroposterior plane than in the transverse plane and in the lower arches than in the upper arches. It was concluded that Class II division 1 subdivision malocclusions are characterized by dental deviations and not skeletal dysplasia in the frontal plane.