Change in the soft tissue profile during and after orthodontic treatment.

The aim of the present study is to describe the changes in the Holdaway angle during and after treatment with a fixed appliance and to search for any possible differences between non-extraction treatment and extraction treatment. Thirty-five randomly selected Angle Class II. Division I cases with complete records before treatment, at the end of treatment, and at time at least one year out of retention, were collected. The sample was divided into two groups, one consisting of nineteen non-extraction cases and the other group of sixteen extraction cases. All cephalometric radiographs were traced on to acetate film and a computer program developed for cephalometric analysis according to the Bergen Technique was used to evaluate the radiographs. A computer program was used for the statistical evaluation of the data. In conclusion it can be said that no significant differences with regard to the Holdaway angle were found between fixed appliance therapy with or without extraction. A significant influence on the Holdaway angle itemed from the sagittal base relation (ANB) and chin prominence. It seems reasonable to assume that only orthopaedic appliances that influence sagittal base relationship, and especially the lower jaw, can have a profound influence on Holdaway angle.