The passive activator: Case selection, treatment response, and corrective mechanics

Abstract

A brief description of the design, function, and clinical control of the activator has been presented. In order to build a basis for the effective clinical use of the activator, and to know what can be expected from the activator, an experiment was designed around thirty-one Class II, Division 1 patients selected empirically by Eastwood's criteria and treated to “activator completion.” Also considered were Steiner and Ricketts analyses to determine cephalometric features common to this sample. Treatment effects were derived by the use of RMDS growth forecasts. The models were also analyzed to record changes in molar relationship, intermolar width, intercanine width, arch length, and overjet. Overbite was measured from the cephalograms. To record any rotation of the mandible during treatment, the Jarabak index was used. Lower incisor behavior was followed closely to record any movement. Finally, to investigate treatment timing, the sample's starting times were superimposed on Woodside's growth and velocity curves. Many skeletal and dental activator-induced changes were noted to be highly significant statistically. Ten mechanisms involved in the correction were described, along with nine clinical implications. Five cases were presented to illustrate some of the points.