Skeletal and dental changes with nonextraction Begg mechanotherapy in patients with Class II Division 1 malocclusion

This prospective cephalometric study was undertaken to assess the mode and magnitude of Class II correction with nonextraction Begg mechanotherapy in growing children. The sample comprised subjects with similar malocclusion a nd age range (9-12 years) who were specifically selected for nonextraction Begg mechanotherapy. Cephalograms were analyzed to assess the skeletal, den tal, and soft tissue changes that occurred after correction of the molar re lationship, the overjet, and the overbite during the g-month treatment peri od. The results revealed a significant improvement in the anteroposterior j aw relationship, suggested by the significant reduction in the ANB angle (1 .62 degrees) and in Wits AO-BO (1.42 mm). The mandibular length increase of 0.56 mm suggests that the Class II elastics used in nonextraction Begg mec hanotherapy had a minimal stimulatory effect on mandibular growth. There wa s a significant increase in the anterior and posterior facial heights and t he ramal height. Almost all of the dental changes were significant. The mos t striking feature were a significant retraction and extrusion of the maxil lary incisors and proclination and intrusion of the lower incisors accompan ied by extrusion of the mandibular molars. The maxillary incisors extruded by 1.64 mm under the influence of the undesirable downward component of the Class II elastic forces. The major contribution to overjet and molar corre ction was predominantly dentoalveolar.