A Comparative Study of Occlusal Muscle Activity in Patients with Bite Clenching Syndrome and Normal Subjects

<p>  [Purpose] The purpose of this study was to investigate the masseter muscle activity during meals in patients with bite clenching syndrome and normal subjects using a simple electromyograph. [Methods] The subjects were one healthy person who was not under dental treatment and one patient with Dental Disstress Syndrome. Recording electrodes were placed on the right masseter muscle, and electromyogram (EMG) was measured at four different times : a : maximum bite, b : minimum bite, c : during gum chewing, and d : during banana chewing. As a result, the average Root Mean Square (RMS) value of each was calculated. [Results] The mean RMS of healthy subjects was a : 1.21±0.21, b : 0.06±0.01, c : 0.44±0.20, d : 0.23±0.05 (μV), and that of patients was a : 3.35±0.38, b : 0.07±0.01, c : 1.14±0.26, d : 0.40±0.05 (μV). In the case of gum, the myoelectric amplitude decreased as the gum softened from solid to moist. In addition, the timing of biting was periodic and constant, indicating that the patient was able to chew the gum with saliva. On the contrary, the patient’s muscle activity showed that the bite force was not periodic and indefinite. Especially for chewing gum, the myoelectric amplitude increased with repeated chewing of food, indicating that the patient may not be able to grasp the appropriate bite force. [Discussion] The patient’s muscle activity is greater during food chewing, and the patient may not be able to grasp the appropriate bite force themself. If these sensory receptors are blocked due to disease, it is possible to compensate and relearn sensation by using visual feedback such as electromyography, auditory feedback. In the case of a disease, there is a possibility that compensation and sensory relearning can be achieved.</p>