Modulation of Masseteric Reflexes by Simulated Mastication

Abstract

It is well-known that limb muscle reflexes are modulated during human movements. However, little is known about the existence of equivalent masticatory muscle reflex modulation. We hypothesized that masticatory reflexes would be modulated during chewing so that smooth masticatory movements occur. To examine this hypothesis, we studied the modulation of inhibitory reflexes evoked by periodontal mechanoreceptor activation and of excitatory reflexes evoked by muscle spindle activation during simulated mastication. In 28 participants, 1- and 2-N mechanical taps were delivered to the incisor. Reflex responses to these taps were examined in the average masseteric electromyogram. To differentiate between periodontal mechanoreceptor- and muscle-spindle-mediated reflex components, we performed experiments prior to, and in the presence of, periodontal anesthesia. Both periodontal mechanoreceptor and muscle spindle reflexes were reduced during simulated masticatory movements.

Neuromuscular control of balancing side contacts in unilateral biting and chewing

“…Such views are mainly based on unloading reflexes studied in clenching or simulated chewing experiments. These were mostly performed with big jaw gapes [33,[42][43][44][45][46][47][48] and with inhibitory responses elicited by extra-or intraoral stimuli but not by direct tooth contacts. Several arguments question the suitability of reflex control for occlusal protection in masticatory power strokes: Due to latencies, inhibition of muscle force possibly triggered by tooth contacts would be delayed and would counteract the buildup of chewing force [18,33].…”

“…Several arguments question the suitability of reflex control for occlusal protection in masticatory power strokes: Due to latencies, inhibition of muscle force possibly triggered by tooth contacts would be delayed and would counteract the buildup of chewing force [18,33]. Further, inhibitory reflexes lose effectiveness when jaw gapes decrease [42][43][44][45]. Hence, it was supposed that close to occlusion, inhibitory response to unharmful stimuli is reduced so that the required rise of chewing force is not disrupted [33,43,46,49].…”

Alternatives to Radiation Investigations in Orthodontics

“…Muscle spindle reflexes are stronger in short face height individuals 17,34 which may explain the phenomenon with bruxism and brachyfacial tendency. Moreover, this information may translate into better designs for splints and Orthodontic appliances.…”

“…Minimizing artifacts is essential for clear data recording and minimizing movements from adjacent muscles is very helpful. In the study by author 34 , the customized nose rest and the head halo provided stabilization during the chewing and static phases of the experiments (Fig. 3).…”

roefschriften 25 jaar na dato 32. Fysiologische aspecten van het kauwproces

“…Het perifeer geïnduceerde deel begon ongeveer 25 milliseconden na de uitgeoefende externe kracht. Ongeveer 85% van de totale spieractiviteit werd perifeer geïnduceerd, hetgeen betekent dat de spieractiviteit voor het grootste deel wordt opgewekt als gevolg van sensorische informatie over de actuele kauwslag (Ottenhoff et al, 1992;Abbink et al, 1998;Naser-Ud-Dins et al, 2010). Het kauwproces wordt dus voor een groot deel reflexmatig gestuurd.…”