engleski

Activity of craniomandibular muscles during functional movements of the mandible

Activity of craniomandibular muscles during functional movements of the mandible. M. Valentić-Peruzović*, A. Čelebić, M. Cifrek, R. Magjarević (School of Dental Medicine, Faculty of Electrical Engineering-FER, Univ. Zagreb, Zagreb, Croatia, Europe). Electromyography (EMG) is used in dentistry to assess the relationship between the activity of craniomandibular muscles during different functional and border movements and occlusal conditions. The aim of this study was to analyse electromyographic activity of the right and left temporal and masseter muscles during various teeth contacts. Surface electrodes and an 8-channel PC-based programable system were used for EMG registrations and the analysis of the results. Ten (10) subjects (7 males and 3 females) ages 23-45, with natural asymptomatic dentition participated in this study. A series of functional and border movements was registered, such as maximum voluntary clench in the intercuspal position (MIK), unilateral bite in right and left excentric positions (RO, LO), bite in protruded (P) and retruded (R) position, unilateral and frontal chewing of chewing gum (Ch-R, Ch-L, Ch-F), natural and water swallowing (Sw-1, Sw-2) and so on.The results were calculated and expressed in percent of the maximum voluntary clenching force (% MVC). The range of the temporal muscles' border movement activity was between 12.83 % in P and 70.05 % in R. In the lateral position the activity of ipsilateral temporalis was RT 66.64 % and LT 57.50 %, and on the contralateral side 24.10 % and 23.20 %. Masseter muscles showed less variability concerning border movements RO, LO, P, R (36.86 % - 48.86 %). Also lower values were obtained in functional movements such as chewing and swallowing (16.13 % - 33.20 %). These results confirmed that temporal muscle is very sensitive to changes in position of the mandible, showing decreased activity in protrusive position, and increased activity in retruded position. Masseter muscle is almost constant in the activity range < 50 % of MVC. Supported by Ministry of Science and Technology, Republic of Croatia, Project No.65011

Electromyography (EMG); dentistry; temporal and masseter muscles; position of the mandible

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