This article examines some of the differences between successfully and unsuccessfully treated malocclusions. The sample consists of an untreated control group, a successfully treated group, and an unsuccessfully treated group. On both treatment groups an 0.022 edgewise appliance with directional forces mechanics was used. The skeletal and dental differences between these groups at the end of the treatment time interval are studied and discussed. The patient records of unsuccessful correction and of successful correction are presented for comparison. (AM J ORTHOD DENTOFAC ORTHOP 1995;107:434-43.)