Effect of the Oral Sensory Function on the Activities of Masticatory Muscles

Yamashina, Toru; Fujii, Hideyo; Munehisa, Nobuhiro; Nagasawa, Tooru; Tsuru, Hiromichi

doi:10.2186/jjps.21.525

Cited by 3 publications

(2 citation statements)

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“…The total masseter electric discharge duration after the anesthetization decreased as compared with that before the anesthetization. Although Yamashina et al 32) did not assess the initial components of masseter electric discharges before and after the anesthetization in the chewing motion in their experiment with the periodontal membrane on the chewing side under anesthetization, they reported that the total masseter electric discharge duration markedly decreases after the anesthetization. This decreased masseter electric discharge duration agreed with our results.…”

Section: Patterns Of Masseter Electric Discharges Before and After Anesthetizationmentioning

confidence: 98%

Changes in cortical negative potential associated with local anesthetization of apex of tooth root

Uchida

Yoshida

Yamaguchi

2006

Pediatric Dental Journal

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To determine whether cortical negative potential (hereafter referred to as CNP), which was recorded from the scalp (sites: T3, CZ and T4), preceding the right-side chewing is affected by input from the periodontal membrane, the CNP and pattern of the appearance of masseter electric discharge before the anesthetization of the apex of the tooth root and those after the anesthetization were compared. 1) CNP preceding the right-side chewing appeared at T4 early both before and after the anesthetization and showed a maximum amplitude immediately before masseter electric discharge. CNP duration and amplitude increased after the anesthetization as compared with those before the anesthetization.2) The initial increase in electromyogram associated with chewing became sharper after the anesthetization than before the anesthetization. From these findings, that the cerebral cortex is in a preparatory state at an early stage when the sensation in the periodontal membrane on the chewing side is blocked, and that, as a consequence, strong chewing is produced.recorded from an outside lateral area corresponding to hand motor function. However, they observed CNP only in one hemisphere, and did not investigate the distribution of CNP appearance in the entire brain in detail.Nakajima et al. 1,2) compared the distributions of CNP appearance ipsilateral and contralateral to the chewing side and reported that the ipsilateral distribution of CNP appearance is predominant. Tanaka et al. 3) recorded the topography of CNP from electrodes placed at 12 sites of the scalp and reported that CNP for the chewing motion is localized to the temporal area ipsilateral to the chewing side 50 to 70 ms before the start of masseter electric discharge.On the other hand, the chewing motion functions to crush food voluntarily 18) . It is easily conceivable therefore that one's sensation of the periodontal membrane has a great effect on one's occlusion force and chewing force depending on one's dental

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Section: Patterns Of Masseter Electric Discharges Before and After Anesthetizationmentioning

confidence: 98%

Changes in cortical negative potential associated with local anesthetization of apex of tooth root

Uchida

Yoshida

Yamaguchi

2006

Pediatric Dental Journal

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“…This was more pronounced in the masseter muscle than in the temporal muscle. D/S values are great in subjects with complete dentures 14) and in subjects with poor masticatory abilities 9) . This suggests that increases in D/S express difficulty in masticating.…”

Section: Electromyograms During Masticatory Movementmentioning

confidence: 99%

An Electromyogram Study on Mandibular Movement in Unilateral Cleft Lip and Palate Patients Before and After Orthodontic Treatment.

Sakamoto

Ohtsuka

Harazaki

et al. 1999

Bull. Tokyo Dent. Coll.

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The purpose of this study is to investigate masticatory muscle function in subjects with unilateral cleft lip and palate compared with normal occlusion and the extents of improvement before and after orthodontic treatment. Subjects were twenty pretreatment patients, thirty posttreatment patients and ten controls. Electromyograms were recorded from their masticatory muscles during masticatory movement and tapping movement.Reduction of duration/stroke ratio (D/S) was observed in electromyograms obtained during masticatory movement after orthodontic treatment. The reduction was especially notable in the masseter muscle. In spite of a significant reduction in coefficient of variation (CV) values, a significant difference between the posttreatment group and the control group indicated some persisting irregularity in masticatory movement. Electromyograms taken during tapping movement showed no change in latency in the posttreatment group, but duration of the silent period (SP) was shortened and SP appearance increased. The findings outlined above reveal electromyographically clear improvements in masticatory muscle functions and jaw reflex mechanisms after orthodontic treatment. Nevertheless, parameters for subjects with cleft lip and palate still differed from those for controls with normal occlusion. The influence of plastic surgery in subjects with the defects discussed here causes maxillary retrusion, which in turn results in skeletal malocclusion. Orthodontic treatment should be designed to compensate this dentally and alveolarly. This design and the need to improve masticatory functions would contribute to eliminate the extreme difficulty of the therapeutic process.

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Differential lissajous EMG of masticatory muscles and its application in man.

Kumai

Nomura

1989

Jpn J Oral Biol

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Abstract:Difference in the activity of masticatory muscles between subjects with normal teeth alighnment and occlusion and patients with disorders at the oral region was investigated using a differential Lissajous EMG method. Surface EMGs were recorded from the right and left temporal and masseter muscles during peanut and chewing gum mastications. The difference of the integrated EMGs between both sides was obtained in both the temporals and masseters, then two differences were synthesized to a Lissajous figure. The figures generally showed the followings. 1) In the normal subjects, the muscle behaviour varied from strkoe to stroke in peanut mastication, while it was constant in chewing gum mastication. 2) Activity of some muscles of the patients was quitely weak, while that of the normal subjects was totally balanced. 3) In the patiens, combination of use between the temporal and masseter muscles and contraction order among the muscles tended to be reversed compared to the normal subjects.

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Effect of the Oral Sensory Function on the Activities of Masticatory Muscles

Cited by 3 publications

References 0 publications

Changes in cortical negative potential associated with local anesthetization of apex of tooth root

Changes in cortical negative potential associated with local anesthetization of apex of tooth root

An Electromyogram Study on Mandibular Movement in Unilateral Cleft Lip and Palate Patients Before and After Orthodontic Treatment.

Differential lissajous EMG of masticatory muscles and its application in man.

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