[Electromyographic findings on the external pterygoid muscle during activator therapy for distal bite].

First the author describes how the activator after Herren works, and the part played by the masticatory muscles. In a long-term study the functional behaviour of the external pterygoid muscle during activator therapy on children was investigated by electromyographic recording. Its results are discussed and compared to conclusions from experiments carried out by Petrović et al. concerning the growth of condylar cartilage in rats treated with a device of the postural hyperpropulsive type ("hyperpropulseur").