Condylar development and mandibular rotation and displacement during activator treatment. An implant study.

An analysis of the effects of activator treatment on the spatial development of the mandible over 11 months was performed via the metal implant method for a group of nineteen patients. A series of centers of rotation were derived, the position and effect of which are described and related to observed changes in basal and dentoalveolar structures and the development of the mandibular condyle. A posteriorly directed condylar development, in conjunction with an anterior rotational pattern, was found to be optimal if a basal Class II malocclusion is to be treated by means of a forward developmental displacement of the mandible.