ELECTROMYOGRAPHIC STANDARDIZED INDICES OF MASTICATION IN HEALTHY BRAZILIAN CHILDREN AND ADULTS

Masticatory muscle EMG was assessed in a group of 13 healthy children (7-12 years old) and a group of healthy adults (21-30 years old) performing 15s unilateral gum chewing. By means of a wireless electromyographic analyzer, masseter and temporalis muscles' standardized activities were investigated, and the two groups' resulting characterization compared. As well as chewing frequency, a bivariate analysis was performed on the simultaneous differential right-left masseter (ΔM) and temporalis (ΔT) activity (Lissajous's plot) to analyze the coordination pattern. Symmetry indices, effort-related parameters and intra-group variability were also assessed. The outcomes showed that healthy children had a good muscular coordination, comparable with adults' condition. Though, in children, the working-side muscular prevalent activity (a physiologic condition) was significantly smaller than in adults, probably due to the neuromuscular immaturity that appears in less selected muscular side recruitment. Children also showed an accentuated divergence in muscular activation variability pattern between the two chewing sides, suggesting the existence of a temporary preferred side of mastication, likely induced by an asymmetric acute state of occlusal development. Different stages of stomatognathic apparatus development could explain the larger variability of children's chewing frequency. Overall, these control data provide reference database for the assessment of patients, either children or adults, with functionally altered stomatognathic conditions.