Ultrasonography and electromyography of masticatory muscles in a group of adolescents with signs and symptoms of TMD.

The thickness and electrical activity of masseter and anterior temporalis muscles were compared in adolescents with and without signs and symptoms of TMD. Forty individuals were selected using the Cranio Mandibular Index and a questionnaire. There was no significant correlation between thickness and activity (p > 0.05). However, there were correlations between thickness and weight and height (p < 0.05). The effect of signs and symptoms on muscle thickness and activity was weak, considering the low CMI scores found.