Vertical jaw separation and masseter muscle electromyographic activity: a comparative study between asymptomatic controls & patients with temporomandibular pain & dysfunction

Temporomandibular dysfunction (TMD) is a complex disturbance that involves the masticatory muscles and/or temporomandibular joint, causing damage to the masticatory function. This study evaluated the electromyographic activity of the masseter muscle during habitual mastication of bread, apple, banana, cashew nut and paraffin film (Parafilm M) in 25 adult subjects, of both gender, with TMD. The results were compared to those of a control group, composed of 15 adult subjects, of both sexes, free of signs and/or symptoms of TMD. The MYO-TRONICS Inc., K6-I computer software was used for electromyographic processing and analyzed the following parameters: duration of the act, duration of the masticatory cycle and number of cycles. No significant differences were found between subjects in the control group and individuals with TMD as to duration of the masticatory act and of the masticatory cycle, considering all materials used for mastication. The duration of the masticatory act and cycle was longer during mastication of paraffin film in both groups. The number of masticatory cycles was higher for mastication of apple in comparison to mastication of banana, in both groups. It can be concluded that the consistency of foods influences the duration parameters of the act, duration of the cycle and the number of masticatory cycles, and the behavior of the masticatory muscles in individuals with TMD during habitual mastication is similar to that verified in individuals without TMD.

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Electromyographic activity of the jaw-closing muscles during jaw opening - comparison of cases of masseter muscle contracture and TMJ closed lock

Journal of Oral Rehabilitation ◽

10.1046/j.1365-2842.2002.00965.x ◽

2002 ◽

Vol 29 (11) ◽

pp. 1063-1068 ◽

Cited By ~ 9

Author(s):

T. Yamaguchi ◽

K. Satoh ◽

K. Komatsu ◽

K. Kojima ◽

N. Inoue ◽

...

Keyword(s):

Masseter Muscle ◽

Electromyographic Activity ◽

Muscle Contracture ◽

Jaw Opening ◽

Closed Lock

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Bite force and masseter muscle electromyographic activity during onset of an isometric clench in man

Archives of Oral Biology ◽

10.1016/0003-9969(85)90035-4 ◽

1985 ◽

Vol 30 (3) ◽

pp. 213-215 ◽

Cited By ~ 21

Author(s):

H. Devlin ◽

D.G. Wastel

Keyword(s):

Masseter Muscle ◽

Bite Force ◽

Electromyographic Activity

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Stomathognatic system function in indigenous people from Brazilian Xingu villages: An electromyographic analysis

PLoS ONE ◽

10.1371/journal.pone.0243495 ◽

2020 ◽

Vol 15 (12) ◽

pp. e0243495

Author(s):

Carla Moreto Santos ◽

Marcelo Palinkas ◽

Wilson Mestriner-Júnior ◽

Isabela Hallak Regalo ◽

Paulo Batista de Vasconcelos ◽

...

Keyword(s):

Postural Balance ◽

Masseter Muscle ◽

Masticatory Muscles ◽

Electromyographic Activity ◽

System Function ◽

Masticatory Efficiency ◽

Indigenous Group ◽

Electromyographic Analysis ◽

Student’S T ◽

Student’S T Test

The maintenance of postural balance can be influenced by the lifestyle of a population. This study aimed to determine the electromyographic activity of the masseter and temporalis muscles during mandibular tasks and habitual and non-habitual chewing in indigenous individuals to reveal the differences among white Brazilian individuals. Sixty Brazilians (18 and 28 years) were divided into two groups: 30 Xingu indigenous individuals and 30 white Brazilian individuals, with 20 men and 10 women in each group. The individuals were assessed using the normalized electromyographic activity of mandibular tasks (rest, protrusion, right and left laterality) and electromyographic activity of masticatory cycles in habitual (peanuts and raisins) and non-habitual (Parafilm M) chewing. Data were analyzed using Student’s t-test (p < .05). Comparisons between the groups demonstrated significant differences. Indigenous individuals group presented a decrease in the normalized electromyographic activity of the masticatory muscles during mandibular rest [right masseter (p = .002) and left masseter (p = .004) muscles]. There was increase in the normalized electromyographic activity during protrusion [left temporal (p = .03) muscle]. There was increase in the electromyographic activity during chewing: peanuts [right masseter (p = .001), left masseter (p = .001) and right temporal (p = .01) muscles], raisins [right masseter (p = .001), left masseter (p = .002), right temporal (p = .008), left temporal (p = .01) muscles] and Parafilm M [left masseter muscle (p = .05)]. From the findings of this study, we concluded that in the comparison between indigenous and white individuals, positive changes were observed in the electromyographic pattern of the masticatory muscles in the mandibular postural conditions, with greater masticatory efficiency in the indigenous group.

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Integrated electromyographic activity and biting force during rapid isometric contraction of fatigued masseter muscle in man

Archives of Oral Biology ◽

10.1016/0003-9969(81)90175-8 ◽

1981 ◽

Vol 26 (10) ◽

pp. 795-801 ◽

Cited By ~ 18

Author(s):

Y. Kawazoe ◽

H. Kotani ◽

T. Maetani ◽

H. Yatani ◽

T. Hamada

Keyword(s):

Isometric Contraction ◽

Masseter Muscle ◽

Electromyographic Activity

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Mental Stress-induced Physiological Changes in the Human Masseter Muscle

Journal of Dental Research ◽

10.1177/154405910408300308 ◽

2004 ◽

Vol 83 (3) ◽

pp. 227-231 ◽

Cited By ~ 33

Author(s):

O. Hidaka ◽

M. Yanagi ◽

K. Takada

Keyword(s):

Mental Stress ◽

Masseter Muscle ◽

Potential Role ◽

Nervous Activity ◽

Masticatory Muscles ◽

Sympathetic Nervous Activity ◽

Electromyographic Activity ◽

Hemodynamic Changes ◽

Stress Task ◽

Sympathetic Nervous

The effect of a long mental stress on the hemodynamics of masticatory muscles has not been investigated to date. We hypothesized some hemodynamic and electromyographic changes in jaw-closure muscles related to sympathetic nervous system activity. While healthy adult female volunteers performed a two-hour mental stress task, electromyographic activity of the temporal and masseteric muscles was recorded, and hemodynamic changes of the masseter muscle were measured non-invasively. Autonomic function was assessed by heart rate spectral analysis. Integrated electromyographic activity of the temporalis muscle, but not the masseter muscle, showed an increase that coincided with the increase in sympathetic nervous activity. In the masseter muscle, despite little change in integrated electromyographic activity, notable changes were found in hemodynamic parameters. These results suggest that hemodynamics of jaw muscles is susceptible to mental stress, implying a potential role in the etiology of jaw muscle dysfunction associated with mental stress.

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