The purpose of this study was to compare the changes in subjects with Class II division 1
malocclusions treated with and without the extraction of four first premolars. Iateral
cephalograms on 91 patients (44 extraction and 47 nonextraction) were evaluated at three
stages: pretreatment, posttreatment, and approximately 2 years after treatment. The present
findings indicate that before treatment, the upper and lower lips were more protrusive
relative to the esthetic plane among the subjects treated with four first premolar extractions …