Quantitative analysis of masticatory activity during unilateral mastication using muscle fMRI

Yamaguchi, Satoshi; Itoh, S.; Watanabe, Yoshihiko; Tsuboi, Akito; Watanabe, Makoto

doi:10.1111/j.1601-0825.2010.01767.x

Cited by 14 publications

(15 citation statements)

References 32 publications

(51 reference statements)

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“…Thus, mfMRI evaluates skeletal muscle activity differently from EMG; however, exercise-induced shifts in T2 correlate with integrated EMG, exercise intensity and workload (6)(7)(8)(9)(10)(11). In a previous study, we observed high activities of the ipsilateral masseter, ipsilateral medial pterygoid and contralateral lateral pterygoid muscles during unilateral gum-chewing using mfMRI (12).…”

Section: Introductionmentioning

confidence: 87%

Evaluation of masticatory activity during unilateral single tooth clenching using muscle functional magnetic resonance imaging

Okada

Yamaguchi

Watanabe

et al. 2016

J of Oral Rehabilitation

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Masticatory muscle activity during teeth clenching is affected by occlusal pattern. However, few studies have performed simultaneous evaluation of all masticatory activities during teeth clenching under various occlusal conditions. The aim of this study was to use muscle functional magnetic resonance imaging (mfMRI) to evaluate the effects of changes in occlusal point on masticatory activity during single tooth clenching. Changes in mean proton transverse relaxation time (∆T2) as an index of activity in all masticatory muscles during left unilateral clenching at the first molar or first premolar for 1 min were examined in nine healthy volunteers. Bite force was maintained at 40% of the maximum voluntary clenching force. The ∆T2 values of the masseter and lateral pterygoid muscles were analysed separately for superficial and deep layers, and for superior and inferior heads. The ∆T2 values for the ipsilateral deep masseter were significantly lower, and for the superior head of the ipsilateral lateral pterygoid muscles were significantly higher, after left first premolar clenching compared to left first molar clenching. These results quantitatively demonstrate a significant increase in activity of the superior head of the ipsilateral lateral pterygoid muscle and a significant decrease in activity of the ipsilateral deep masseter muscle with forward displacement of the occlusal contact point during unilateral tooth clenching.

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Section: Introductionmentioning

confidence: 87%

Evaluation of masticatory activity during unilateral single tooth clenching using muscle functional magnetic resonance imaging

Okada

Yamaguchi

Watanabe

et al. 2016

J of Oral Rehabilitation

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show abstract

“…From 9 of 11 subjects, scans were acquired after 2 sets of swallowing exercises with an interval of 20 minutes' rest between tasks. As a positive control, the remaining 2 subjects performed a prolonged bite (80 seconds) to demonstrate that the change in T2 signal does localize to active muscle (13). …”

Section: Methodsmentioning

confidence: 99%

Evaluating Swallowing Muscles Essential for Hyolaryngeal Elevation by Using Muscle Functional Magnetic Resonance Imaging

Pearson

Hindson

Langmore

et al. 2013

International Journal of Radiation Oncology*Biology*Physics

114

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Summary Elevation of the larynx is critical to swallowing function, an observation supported by the fact that radiation therapy-induced dysphagia is associated with reduced laryngeal elevation. We investigated muscles underlying hyolaryngeal elevation by using muscle functional MRI. We acquired scans from 11 healthy subjects to determine whole-muscle T2 signal profiles pre-swallowing, post-swallowing, and after performing swallowing exercises. Results demonstrate muscles essential to laryngeal elevation and exercises that target them. Purpose Reduced hyolaryngeal elevation, a critical event in swallowing, is associated with radiation therapy. Two muscle groups that suspend the hyoid, larynx, and pharynx have been proposed to elevate the hyolaryngeal complex: the suprahyoid and longitudinal pharyngeal muscles. Thought to assist both groups is the thyrohyoid, a muscle intrinsic to the hyolaryngeal complex. Intensity modulated radiation therapy guidelines designed to preserve structures important to swallowing currently exclude the suprahyoid and thyrohyoid muscles. This study used muscle functional magnetic resonance imaging (mfMRI) in normal healthy adults to determine whether both muscle groups are active in swallowing and to test therapeutic exercises thought to be specific to hyolaryngeal elevation. Methods and Materials mfMRI data were acquired from 11 healthy subjects before and after normal swallowing and after swallowing exercise regimens (the Mendelsohn maneuver and effortful pitch glide). Whole-muscle transverse relaxation time (T2 signal, measured in milliseconds) profiles of 7 test muscles were used to evaluate the physiologic response of each muscle to each condition. Changes in effect size (using the Cohen d measure) of whole-muscle T2 profiles were used to determine which muscles underlie swallowing and swallowing exercises. Results Post-swallowing effect size changes (where a d value of >0.20 indicates significant activity during swallowing) for the T2 signal profile of the thyrohyoid was a d value of 0.09; a d value of 0.40 for the mylohyoid, 0.80 for the geniohyoid, 0.04 for the anterior digastric, and 0.25 for the posterior digastric-stylohyoid in the suprahyoid muscle group; and d values of 0.47 for the palatopharyngeus and 0.28 for the stylopharyngeus muscles in the longitudinal pharyngeal muscle group. The Mendelsohn maneuver and effortful pitch glide swallowing exercises showed significant effect size changes for all muscles tested, except for the thyrohyoid. Conclusions Muscles of both the suprahyoid and the longitudinal pharyngeal muscle groups are active in swallowing, and both swallowing exercises effectively target muscles elevating the hyolaryngeal complex. mfMRI is useful in testing swallowing muscle function.

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“…The masseter muscle is an important component of the stomatognathic system, being one of the major muscles related to the bite 1,2 . Due to its morphological constitution and important participation in mandibular kinetics, it can be considered one of the basis of the stomatognathic system 3 .…”

Section: Introductionmentioning

confidence: 99%

Relação da espessura e da atividade elétrica do músculo masseter com a força de mordida: um estudo morfológico e eletrofisiológico

et al. 2016

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RESUMO: Objetivo: estudar a relação da espessura e da atividade elétrica do músculo masseter com a força de mordida. Métodos: participaram do estudo 17 adultos jovens (21,3 ( 1,4 anos), sendo 7 do gênero feminino e 10 do gênero masculino, saudáveis e clinicamente assintomáticos, quanto a disfunções temporomandibulares. Foi efetuada a medida da espessura do músculo masseter unilateralmente, durante o repouso e contração voluntária máxima. Também foi quantificada a força de mordida para cada lado com um transdutor de força posicionado na região do primeiro molar e simultaneamente avaliou-se atividade elétrica do masseter durante a mordida unilateral. A análise foi baseada na comparação das amostras, sendo utilizados o test t, Wilcoxon, Mann-Whitney e regressão linear multivariada. Resultado: a espessura do músculo masseter foi maior nos homens, tanto no repouso quanto em contração. Observou-se uma simetria entre os lados com os músculos em repouso e em contração. A frequência mediana do sinal eletromiográfico, para o músculo masseter em contração voluntária máxima, não apresentou diferença estatisticamente significante intra-indivíduos e na comparação entre os gêneros. Foi encontrada maior força de mordida nos indivíduos do gênero masculino. Não foi encontrado um modelo de regressão linear multivariada entre as variáveis estudadas. Conclusão: neste estudo, não foi possível encontrar um modelo linear com as variáveis estudadas.

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Quantitative analysis of masticatory activity during unilateral mastication using muscle fMRI

Abstract: These results affirm the importance of the ipsilateral masseter muscle and quantitatively demonstrate the important contribution of the ipsilateral medial pterygoid and contralateral lateral pterygoid muscles during unilateral mastication.

Cited by 14 publications

References 32 publications

Evaluation of masticatory activity during unilateral single tooth clenching using muscle functional magnetic resonance imaging

Evaluation of masticatory activity during unilateral single tooth clenching using muscle functional magnetic resonance imaging

Evaluating Swallowing Muscles Essential for Hyolaryngeal Elevation by Using Muscle Functional Magnetic Resonance Imaging

Relação da espessura e da atividade elétrica do músculo masseter com a força de mordida: um estudo morfológico e eletrofisiológico

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