Temporomandibular disorders (TMD) are manifested as a group of signs and symptoms that affect a particular population profile. Some variables such as sex and age influence the clinical expression of this condition. This observational descriptive cross-sectional study aimed to correlate the severity of TMD established by the craniomandibular index (CMI) with the variables: age, sex and electromyographic activity of the masseter and anterior temporal muscles. Fifty-four subjects (15 males/39 females) aged between 16 to 65 years (mean age = 41 years) and diagnosed with TMD were evaluated. Severity was determined by the CMI. These subjects also underwent examination by surface electromyography of the masseter and anterior temporal muscles. No correlation was found between age and severity of TMD (p=0.19/r=0.16), however there was a trend of greater severity in young adults (25-50 years). The sex variable in the correlation was positive with the CMI (p=0.03/r=-0.96) and superior to women. A greater EMG activity of the anterior temporal in relation to masseter (p=0.01) was found and the left temporal activity had the highest average (161.5 ± 44.6 Hz). The electromyographic activity of the anterior temporal and right masseter muscles was positively correlated with the Dysfunction Index CMI (p=0.01). The use of CMI to quantify the severity of TMD and of EMG to assess the functionality of the masticatory muscles can be important allies to direct the treatment.
temporomandibular joint dysfunction syndrome; electromyography; severity of illness index
