Correlation between masseter muscle activity and maximum bite force among various facial divergence pattern.

The reflex response of the masseter muscle to the rapid unloading of a single maxillary incisor tooth was studied. Unloading of a static force of 2 N in the horizontal direction resulted in a short-latency excitation, inhibition, and long-latency excitation of masseter muscle activity occurring at latencies of approximately 13, 20, and 40 ms, respectively, with a corresponding change in bite force occurring slightly later in each case. Following the blocking of periodontal input by the injection of local anesthetic around the stimulated tooth, inhibitory responses were abolished. Therefore, it is concluded that the observed masseteric inhibition was caused by the unloading of periodontal mechanoreceptors and thus that these receptors may contribute to the jaw unloading reflex.

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Jaw Reflexes Evoked by Mechanical Stimulation of Teeth in Humans

Journal of Neurophysiology ◽

10.1152/jn.1999.81.5.2156 ◽

1999 ◽

Vol 81 (5) ◽

pp. 2156-2163 ◽

Cited By ~ 20

Author(s):

J. Yang ◽

K. S. Türker

Keyword(s):

Mechanical Stimulation ◽

Masseter Muscle ◽

Response Pattern ◽

Bite Force ◽

Reflex Response ◽

Incisor Tooth ◽

Jaw Muscles ◽

Reflex Responses ◽

Closing Force ◽

Stimulation Of

Jaw reflexes evoked by mechanical stimulation of teeth in humans. The reflex response of jaw muscles to mechanical stimulation of an upper incisor tooth was investigated using the surface electromyogram (SEMG) of the masseter muscle and the bite force. With a slowly rising stimulus, the reflex response obtained on the masseter SEMG showed three different patterns of reflex responses; sole excitation, sole inhibition, and inhibition followed by excitation. Simultaneously recorded bite force, however, exhibited mainly one reflex response pattern, a decrease followed by an increase in the net closing force. A rapidly rising stimulus also induced several different patterns of reflex responses in the masseter SEMG. When the simultaneously recorded bite force was analyzed, however, there was only one reflex response pattern, a decrease in the net closing force. Therefore, the reflex change in the masseter muscle is not a good representative of the net reflex response of all jaw muscles to mechanical tooth stimulation. The net response is best expressed by the averaged bite force. The averaged bite force records showed that when the stimulus force was developing rapidly, the periodontal reflex could reduce the bite force and hence protect the teeth and supporting tissues from damaging forces. It also can increase the bite force; this might help keep food between the teeth if the change in force rate is slow, especially when the initial bite force is low.

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Effects of orthodontic archwire changes on masseter muscle activity

American Journal of Orthodontics ◽

10.1016/0002-9416(84)90154-4 ◽

1984 ◽

Vol 86 (4) ◽

pp. 353 ◽

Cited By ~ 1

Author(s):

B.R. Smith ◽

C.M. Flanary ◽

C.L. Hurst ◽

J.D. Rugh

Keyword(s):

Muscle Activity ◽

Masseter Muscle

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The power features of Masseter muscle activity in tension-type and migraine without aura headache during open-close clench cycles

PeerJ ◽

10.7717/peerj.3556 ◽

2017 ◽

Vol 5 ◽

pp. e3556 ◽

Cited By ~ 1

Author(s):

Behrouz Alizadeh Savareh ◽

Ali Ghanjal ◽

Azadeh Bashiri ◽

Monireh Motaqhey ◽

Boshra Hatef

Keyword(s):

Muscle Activity ◽

Masseter Muscle ◽

Migraine Without Aura ◽

Mouth Opening ◽

Tension Type Headache ◽

Emg Activity ◽

Statistical Parameters ◽

Signal Energy ◽

Type Headache ◽

Mean Variance

Introduction Different types of headaches and TMJ click influence the masseter muscle activity. The aim of this study was to assess the trend of energy level of the electromyography (EMG) activity of the masseter muscle during open-close clench cycles in migraine without aura (MOA) and tension-type headache (TTH) with or without TMJ click. Methods Twenty-five women with MOA and twenty four women with TTH participated in the study. They matched with 25 healthy subjects, in terms of class of occlusion and prevalence of temporomandibular joint (TMJ) with click. The EMG of both masseter muscles were recorded during open-close clench cycles at a rate of 80 cycles per minute for 15 seconds. The mouth opening was restricted to two centimeters by mandibular motion frame. Signal processing steps have been done on the EMG as: noise removing, smoothing, feature extraction, and statistical analyzing. The six statistical parameters of energy computed were mean, Variance, Skewness, Kurtosis, and first and second half energy over all signal energy. Results A three-way ANOVA indicated that during all the cycles, the mean of energy was more and there was a delay in showing the peak of energy in the masseter of the left side with clicked TMJ in MOA group compared to the two other groups, while this pattern occurred inversely in the side with no-clicked TMJ (P < 0.009). The variation of energy was significantly less in MOA group compared to the two other groups in the no-clicked TMJ (P < 0.003). However, the proportion of the first or second part of signal energy to all energy showed that TTH group had less energy in the first part and more energy in the second part in comparison to the two other groups (P < 0.05). Conclusion The study showed different changes in the energy distribution of masseter muscle activity during cycles in MOA and TTH. MOA, in contrast to TTH, had lateralization effect on EMG and interacted with TMJ click.

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