Neuromuscular function in healthy occlusion

Abstract

This study aimed to measure neuromuscular function for the masticatory muscles under a range of occlusal conditions in healthy, dentate adults. Forty-one subjects conducted maximum voluntary clenches under nine different occlusal loading conditions encompassing bilateral posterior teeth contacts with the mandible in different positions, anterior teeth contacts and unilateral posterior teeth contacts. Surface electromyography was recorded bilaterally from the anterior temporalis, superficial masseter, sternocleidomastoid, anterior digastric and trapezius muscles. Clench condition had a significant effect on muscle function (P = 0.0000) with the maximum function obtained for occlusions with bilateral posterior contacts and the mandible in a stable centric position. The remaining contact points and moving the mandible to a protruded position, whilst keeping posterior contacts, resulted in significantly lower muscle activities. Clench condition also had a significant effect on the per cent overlap, anterior-posterior and torque coefficients (P = 0.0000-0.0024), which describe the degree of symmetry in these muscle activities. Bilateral posterior contact conditions had significantly greater symmetry in muscle activities than anterior contact conditions. Activity in the sternocleidomastoid, anterior digastric and trapezius was consistently low for all clench conditions, i.e. <20% of the maximum voluntary contraction level. In conclusion, during maximum voluntary clenches in a healthy population, maximum masticatory muscle activity requires bilateral posterior contacts and the mandible to be in a stable centric position, whilst with anterior teeth contacts, both the muscle activity and the degree of symmetry in muscle activity are significantly reduced.

Electromyography assessment in zygomaticomaxillary complex fractures

“…To compare EMG recordings among different subjects, it is necessary to relate all measurements to the electrical muscle activity detected during some standardization recording, like a maximum voluntary contraction (MVC) [19]. In this study, we used a cotton piece covered with tape to achieve maximal voluntary contraction of the masseter and temporalis muscles during recording of muscle activity.…”

Neuromuscular adaptations with flexible fixed functional appliance – a 2-year follow-up study

“…Eine gestörte EMG-Aktivität der Kaumuskulatur soll mit einer Höcker-zu-Höcker-Verzahnung korrelieren, und eine stabile Okklusion bildet die Voraussetzung für eine maximale Muskelaktivität beim Beißen [10,11,16]. Beim Zubeißen in maximaler Okklusion wird eine große Anzahl von Mechanorezeptoren aktiviert, die sich im Ligamentum parodontale der Seitenzähne befinden und der Aktivitätshemmung der Kieferlevatoren entgegenwirkt.…”

“…A correlation has been reported between impaired EMG activity from the masticatory muscles and cusp-to-cusp occlusion, and that stable occlusion is a prerequisite for maximum muscle activity during biting [10,11,16]. During biting in maximum occlusion, a vast number of mechanoreceptors located in the periodontal ligaments of the posterior teeth are activated which diminish the jaw elevator muscle inhibition.…”

Standardized Electromyographic Indexes Allow a Reliable Measurement of Masticatory Muscles Function

“…Indeed, the thickness of the hypodermis, crosstalk from different muscles, the instrumental noise and the position of the electrodes relative to the muscle fibers and the motor point can influence the sEMG signal. Taking into account these technical features, a correct sEMG assessment should be performed only with a reproducible protocol, and with standardized⁄ normalized potentials to remove most of biological and technical noise 2,3,8,9,10,13 . The aim of the present study was to evaluate the repeatability of masticatory muscles STANDARDIZED ELECTROMYOGRAPHIC INDEXES ALLOW A RELIABLE MEASUREMENT OF MASTICATORY MUSCLES FUNCTION normalized indexes obtained during maximal voluntary clenching sEMG acquisitions.…”