Effects of orthodontic treatment on the growth of individuals with Class II division 1 malocclusion.

The purpose of this study was to determine the effects of orthodontic treatment on the growth potential and dentofacial characteristics of individuals with Class II, division 1 malocclusion over a 5-year period. The changes were compared to matched, untreated normal individuals. Lateral cephalograms were available on 91 treated Class II, division 1 cases. Of these, 44 individuals (21 males and 23 females) were treated with first premolar extractions and 47 (20 males and 27 females) were treated nonextraction. The Class II groups were compared to 35 normal individuals (20 males and 15 females) matched for age and sex. Pretreatment, the Class II individuals had larger overjet, deeper overbite, larger ANB angle, more retrusive mandible and a convex soft tissue profile. In addition, the upper and lower lips in males, and the lower lip in females were significantly more protrusive in the subjects that were eventually treated with the extraction of four first premolars. At the end of the 5-year observation period, there was an overall "normalization" of the skeletal relationships of the treated Class II subjects in both the extraction and the nonextraction groups when compared to normals. Treatment had a differential impact on the dental relationships as well as on lip prominence as a result of the extraction decision. At the end of the observation period, both males and females in the extraction group had more retrusive maxillary and mandibular incisors as well as more retrusive lips than the corresponding normals. In the nonextraction groups, there was a tendency for both the incisors and the lips to be relatively more protrusive.