[Comparative characteristics of masticatory muscle tonus in children with orthognathic and prognathic deep bites before and after orthodontic treatment].

In 99 orthognathic children 7 to 15 years and 83 age-matched children with deep prognathism the masticatory muscles stiffness was measured in a relatively resting state and maximal voluntary contraction. In children with anomalous occlusion the stiffness of relaxed muscles was increased as related to normal values, and their contractility was reduced. After the orthodontic treatment the indices of muscular tonus improved.