Cephalometric changes in Class II, Division 1 cases after orthopedic treatment with the bioactivator.

The bioactivator is an orthopedic appliance that has been used for 20 years in the treatment of Class II, Division 1 cases. The evaluation of its therapeutic effects was performed in this study of 76 9- to 10-year-old patients (at the beginning of treatment). The treated subjects were separated into two groups: group A (bioactivator only) and group B (bioactivator plus headgear). Group C comprised 14 untreated subjects selected as controls. Various statistical assessments were made to separate growth phenomena from treatment effects. It appears that the bioactivator has an effect not only on the dentition but also on the skeletal structures. In both treated groups, the maxillary changes were related to an increased anterior vertical growth and a posterior sagittal growth. The addition of extraoral force helped to achieve a posterior rotation of the upper jaw. When only the bioactivator was worn, the mandibular changes were more vertical than sagittal. The lower jaw appeared more forward, however. When the bioactivator and the headgear force were used simultaneously, the therapeutic effects seemed to be more sagittal than vertical, as if the occipitally directed force vector inhibits or at least exerts a control on the downward growth tendency. Without being significantly different statistically from one to the other, the treated groups showed a marked improvement of the sagittal jaw discrepancy.