The objective was to evaluate the homogeneous myoelectric activity of the maxillofacial area and to identify the myodynamic musculature balance in children of different ages with a physiological dental occlusion. Sixty children, 30 aged 7–9 years and 30 aged 10–12 years, with an Angle Class I relationship and who had no clinical symptoms, temporomandibular disorders, cross bite, deep bite or open bite, and were not bruxers underwent a surface electromyographic examination. The bioelectric potentials of the left and right temporalis, masseter, suprahyoid and sternocleidomastoid muscles were evaluated in maximum clenching. The electroactivity of the muscles measured with root mean square and average rectified value did not present statistically significant differences between the groups, even though different values in relation to age were found. Among the 7- to 9-year-olds, the root mean square index in maximum clenching for the masticatory muscles was 256.5 ± 9.0 μV on the right and 254.0 ± 7.3 μV on the left and for the suprahyoid muscles was 27.3 ± 3.2 μV and 31.6 ± 3.7 μV, respectively. In the group of 10- to 12-year-olds, the values were 374.8 ± 15.5 μV and 354.0 ± 16.4 μV, respectively, for the masticatory muscles and 23.4 ± 1.9 μV and 22.4 ± 2.1 μV, respectively, for the suprahyoid muscles. Any deviation from the values reported in the present study suggests the presence of occlusal and/or postural problems.
KeywordsClinical research protocol; clinical trial; randomized controlled trial; dental occlusion; stomatognathic system; masticatory system; orthodontics