Mechanism of motor coordination of masseter and temporalis muscles for increased masticatory efficiency in mice

T. Yoshimi, Yoshiyuki Koga, A. Nakamura, A. Fujishita, H. Kohara, E. Moriuchi, K. Yoshimi, C. Y. Tsai, Noriaki Yoshida

研究成果: 雜誌貢獻文章同行評審

14 引文 斯高帕斯(Scopus)


The demand for the use of mice as animal models for elucidating the pathophysiologies and pathogeneses of oral motor disorders has been increasing in recent years, as more and more kinds of genetically modified mice that express functional disorders of the stomatognathic system become available. However, the fundamental characteristics of mouse jaw movements during mastication have yet to be fully elucidated. The purpose of this study was to investigate the roles of the masseter and temporalis muscles, and the mechanisms of motor coordination of these muscles for increasing masticatory efficiency in the closing phase in mice. Twenty-two male Jcl:ICR mice were divided into control (n = 8), masseter-hypofunction (n = 7) and temporalis-hypofunction groups (n = 7). Botulinum neurotoxin type A (BoNT⁄A) was used to induce muscle hypofunction. The masticatory movement path in the horizontal direction during the occlusal phase became unstable after BoNT⁄A injection into the masseter muscle. BoNT⁄A injection into the temporalis muscle decreased antero-posterior excursion of the late-closing phase corresponding to the power phase of the chewing cycle. These results suggest that the masseter plays an important role in stabilizing the grinding path, where the food bolus is ground by sliding the posterior teeth from back to front during the occlusal phase. The temporalis plays a major role in retracting the mandible more posteriorly in the early phase of closing, extending the grinding path. Masticatory efficiency is thus increased based on the coordination of activities by the masseter and temporalis muscles.
頁(從 - 到)363-374
期刊Journal of Oral Rehabilitation
出版狀態已發佈 - 5月 1 2017

ASJC Scopus subject areas

  • 一般牙醫學


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