Stroke: An electromyographic approach to the masseter and temporal muscles, orofacial soft tissue pressure, and occlusal force.

Stroke is a cerebrovascular disease that triggers changes in the central and peripheral nervous systems, and can compromise human body function. This cross-sectional observational study aimed to analyze the electromyographic (EMG) activity of the masseter and temporal muscles, orofacial soft tissue pressure, and strength of occlusal contacts in patients who had suffered a stroke. Twenty-four patients were divided into two groups: stroke (n = 12) and control (n = 12). The EMG of the masseter and temporal muscles was evaluated during mandibular rest, protrusion, right laterality, left laterality, and maximal voluntary contraction. The Iowa Oral Pressure Instrument (IOPI) was used to measure pressure from the tongue, lips, and buccinator muscles. A computerized system for occlusal analysis (T-Scan III) was used to measure the occlusal contact points of the right and left hemiarches (upper and lower) and the upper and lower first molars. Data were subjected to Student's t-test (p < 0.05). The stroke group had lower normalized electromyographic activity, with a significant difference in the left temporal muscle during rest (p = 0.03) when compared to the control group. There was a significant difference between the groups in tongue pressure (p = 0.004) with a lower mean value in the stroke group. There was a significant difference between the groups in the evaluation of the occlusal contact points of the first permanent molars, with a lower mean percentage in the stroke group. The results indicate that stroke negatively affects functional performance of the stomatognathic system.

Evaluation of the electromyographic fatigue of the masseter and temporalis muscles in individuals with osteoporosis.

OBJECTIVES: The objective of this study was to evaluate the electromyographic fatigue of the masseter and temporalis muscles in individuals with and without osteoporosis. METHODS: Median frequency of the initial, mid, and final periods of the electromyographic signal in the 33 subjects with osteoporosis (OG) and 33 subjects without osteoporosis [control (CG)] was analyzed. RESULTS: OG showed a decrease in median frequency along the electromyographic signal, with a significant difference for the right masseter: initial vs. mid periods, initial vs. final periods; left masseter: initial vs. final periods; temporal (right and left): initial vs. mid periods, initial vs. final periods, and mid vs. final periods. Percentage comparison of median frequency between the initial and mid periods and between initial and final periods in the OG showed a significant difference in the masticatory muscles. DISCUSSION: The findings suggest that osteoporosis is associated with changes in the function of masticatory muscles, especially when measured by electromyographic fatigue.