A cephalometric study of Class II Division 1 malocclusions treated with the Jasper Jumper appliance

This lateral cephalometric study investigated the dental and skeletal effects of the Jasper Jumper appliance used in the correction of Class II Division 1 malocclusions. A sample of 36 growing patients treated with the Jasper Jumper appliance was divided into two groups: (1) 24 patients with records obtained at the start and completion of orthodontic treatment, and (2) 12 patients with records available at the beginning and end of the Jumper phase of treatment. Treatment effects were determined by statistical comparisons of cephalometric changes in the patients relative to age-adjusted cephalometric standards, and from structural superimpositions. While the Jumpers were in place, maxillary incisors were retroclined and the molars were moved distally, tipped back, and intruded. The mandibular incisors were proclined and intruded, while the molars were translated mesially, tipped forward, and extruded. Skeletal measures showed reduced forward maxillary displacement and no significant alteration of horizontal mandibular growth. During orthodontic finishing, molar tipping and maxillary incisor retroclination were corrected, although the mandibular incisors remained proclined. In summary, this study found that the Jasper Jumper appliance corrected Class II discrepancies largely through maxillary and mandibular dentoalveolar effects and, to a limited extent, by restraint of forward maxillary growth.