Variation of Power Spectral Density and Energy in Electromyogram of Jaw-Closing Muscles in Children with Class II Malocclusion

Functional appliance therapy has become an accepted method for treatment of malocclusion in children. The myofunctional changes that occur during orthodontic treatment with functional appliances have not been sufficiently investigated. The purpose of this study is to evaluate the effect of the Twin-Block and Herbst appliances on jaw-closing muscles in children with class II malocclusion. The study group consists of 20 children aged between 9-15 with Class II malocclusion. Electromyography (EMG) signals of right anterior temporal and right masseter muscles are recorded with and without the appliances in situ. The recordings are done at the start of the treatment to evaluate the effects of the appliances in voluntary clenching activity. Autoregressive modeling (AR) is performed for feature extraction purposes, and the maximum value of the power spectral density (PSD), the energy of the PSD and the Shannon energy are obtained. The findings indicate that the effect of the appliances on jaw closing muscles activity can be evaluated from the electromyographic recordings. The PSD, the energy of the PSD and the Shannon energy are quite successful in showing the change occurred in the muscles