Nonsurgical orthodontic treatment of an adolescent girl with Class III malocclusion and asymmetric maxillary narrowing

Class III malocclusion is a difficult anomaly to understand. Because not all Class III patients are candidates for surgical correction, patient assessment and selection are especially important in diagnosis and treatment planning. In this article, we report the orthopedic treatment of a teenage girl with a severe skeletal Class III malocclusion. Her ANB angle was −4.5°, and she had a 2-mm anterior crossbite, a 1-mm overbite, and a posterior asymmetric crossbite (greater on the left side). The patient refused surgery. We used a rapid palatal expansion appliance to expand the maxilla, standard edgewise brackets to align the teeth, and reverse headgear to bring the maxilla forward. We performed symmetric expansion, but, because of the asymmetric crossbite in the maxilla, we designed a modified apparatus that permitted greater relapse on 1 side. In this way, the posterior crossbite was ideally corrected by the end of treatment, and ideal overjet and overbite relationships, functional occlusion, and an esthetic facial appearance were all achieved.