The effect of retention on the relapse of Class II Division 1 cases.
Sixty cases of Class II Division 1 malocclusion were studied; 30 of them had been retained after the completion of orthodontic treatment, the other 30 had not and acted as a control group. Using measurements from lateral skull radiographs and statistical analysis, the two groups were compared in respect of skeletal pattern, soft tissue, overjet, overbite and interincisal angle. Both the retained and the non-retained group showed a tendency to relapse after the completion of active treatment; a tendency to relapse even while in retention was observed. The relapse in overjet was found to be more significant than the relapse in overbite. In both groups the relapse in overjet was found to be associated with the size of the original overjet, the overbite at the end of active treatment and the interincisal angle at the end of active treatment. In both groups the relapse in overbite was found to be associated with the size of the original overbite, the change in maxillary-mandibular planes angle and the interincisal angle at the end of active treatment.