Intra-arch maxillary molar distalization appliances for Class II correction.

C II malocclusion, which affects approximately one-third of patients seeking orthodontic treatment, often reflects both dental and skeletal deviations from the norm.1-3 Because it frequently involves excessive overjet,4 it is easily recognized by lay persons, leading to its overrepresentation in orthodontic practices. According to the National Health and Nutrition Estimates Survey III, in which nearly 14,000 U.S. individuals were studied, an overjet of 5mm or more, suggesting Class II malocclusion, occurs in approximately 23% of children, 15% of adolescents, and 13% of adults.5 Consequently, considerable effort has been devoted to identifying the etiologic factors involved in Class II malocclusion. Although the Angle classification of malocclusion is based solely on an occlusal litmus test, the skeletal and dentoalveolar components of inter arch discrepancy are far more complicated. In planning treatment for a Class II patient, consideration must be given to incisor proclination, space requirements, vertical dimension, transverse relationship, and overall facial esthetics, in addition to the interarch molar relationship. Contemporary edgewise extraction treatment (upper premolars or upper and lower premolars) almost always results in forward displacement of the maxillary molars as the molar relationship is corrected. In contrast, edgewise nonextraction treatment predictably results in an absolute distal displacement (bodily movement and tipping) of the maxillary molars.6 For a variety of reasons, scientific or not, orthodontic treatment in the past few decades has tended toward nonextraction. Today, practitioners have at their fingertips a variety of techniques and interarch appliances that can be employed to distalize maxillary molars. The following is an overview of some of the most commonly used interarch devices.