INITIAL EFFECTS OF TREATMENT OF CLASS-II MALOCCLUSION WITH THE HERRENACTIVATOR, ACTIVATOR-HEADGEAR COMBINATION, AND JASPER JUMPER

The initial effects of treatment of Class II, Division 1 malocclusion with an activator, according to Herren (27 patients), with an activato r-headgear combination (20 patients), or with the Jasper jumper applia nce (25 patients) were studied on lateral cephalograms from before and after 6 to 8 months of treatment. The patients' ages ranged from 9 to 12 years. At the end of the period of observation, the correction in overjet and molar relationship was more complete in the patients with the Jasper Jumper than in the patients with the activator. Whereas all the patients with the Jasper Jumper showed neutral occlusion, this wa s the case in only 20 of the 47 patients with the activator, The corre ction of the distal occlusion occurred through a combination of skelet al and dentoalveolar adaptations. Skeletal changes accounted for 42%, 35%, and 48% of the overjet correction by the Herren-type activator, t he headgear-activator, and the Jasper Jumper, respectively. The correc tion of the molar relationship occurred to 55%, 46%, and 38% by skelet al changes in the respective groups. Dentoalveolar compensation (dista l movement of the upper molars, mesial movement of the lower molars) a ppeared to be inversely related to skeletal adaptation. The patients w ith the Jasper Jumper showed a marked intrusion of the lower incisors with a consequent reduction in overbite.