An electromyographic study of post retraction orthodontic patients.

19 patients treated by the Begg technique 7 patients treated by the Edgewise technique and 15 cases treated by a functional technique who had been at from 1-10 years without any form of retention were recorded electromyographically and their patterns of activity compared with those of patients who had a normal occlusion and who had not received orthodontic treatment. In the interocclusal position the patients who had received functional treatment had a balanced activity and were similar to those with a normal occlusion but this was not so when biting on cardboard 0.5 mm thick. The Begg cases were balanced but the amount of activity was reduced by half; the Edgewise cases were balanced when biting on cardboards and were then similar to those with a normal occlusion.