Electromyographic Activities of Masticatory Muscles in Class III Patients Treated by Facemask With Miniplate Anchorage

Aim: The aim of this study was to investigate electromyographic (EMG) activities of left and right anterior temporal, masseter, and anterior digastric muscles during resting, maximum voluntary clenching, and swallowing before and after facemask treatment. Materials and Methods: Fifteen patients with Class III malocclusion (mean age, 12.1 6 1.43 years) were included in this study. The patients were treated by means of facemask with miniplate anchorage after 8 weeks of alternate rapid maxillary expansion and constriction (Alt-RAMEC) protocol. Before and after treatment, EMG examinations during resting, maximum voluntary clenching, and swallowing were carried out on all subjects. Total treatment time was 9.9 6 2.63 months. Changes in the activities of right and left anterior temporal, masseter, and anterior digastric muscles were tested by using the Wilcoxon signed rank test. Results: The EMG activities of left and right anterior temporal, masseter, and anterior digastric muscles during resting, maximum voluntary clenching, and swallowing did not show any statistically significant changes after treatment (p..05). Conclusion: The EMG evaluation showed that facemask treatment with miniplate anchorage after the Alt-RAMEC protocol did not change the EMG activities of left and right anterior temporal, masseter, and anterior digastric muscles in patients with Class III malocclusion. (Turkish J Orthod 2013;26:65–71)