Variations in activities of human jaw muscles depend on tooth-tipping moments

S. Uchida, L. R. Iwasaki, David B Marx, Y. Yotsui, H. Inoue, J. C. Nickel

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Static mechanical analyses of the masticatory apparatus often assume that jaw muscle activity, as measured using electromyography (EMG), is linearly and constantly related to magnitude of bite force during biting, regardless of bite force-induced tooth-tipping moments. The objective of this study was to test the hypothesis that the relationship between EMG of the jaw muscles and bite force varies with the magnitude and sign of tooth-tipping moments. Seven healthy male subjects produced unilateral static occlusal forces at five biting positions, resulting in sequential changes from buccal (+) to lingual (-) tipping moments on the mandibular first molar. Jaw muscle activities were recorded bilaterally using surface (for temporalis and masseter muscles) and indwelling (for lateral pterygoid muscles) electrodes. Bite forces were recorded and controlled using custom devices. EMG versus bite force data were plotted and regression relationships were calculated for each subject, muscle and biting position. Linear regression analysis, analysis of variance and Bonferroni adjusted least significant difference tests were used to determine the effects of muscle, side (ipsilateral, contralateral) and biting position within subjects. It was found that the relationship between EMG and bite force for different tipping moments differed significantly within a subject and muscle. This was most common in the lateral pterygoid and temporalis muscles (all P ≤ 0.042), where slopes of the EMG:bite force relationship varied between 3:1 and >25:1. In the masseter muscle, the EMG:bite force relationship for different tipping moments differed significantly in one subject (P < 0.008); slopes varied up to 4.6:1. In conclusion, the relationship between EMG and bite force was linear. However, the slopes of the relationship changed significantly depending on sign (+, -) and magnitude of tipping moments acting on the molars.

Original languageEnglish (US)
Pages (from-to)199-205
Number of pages7
JournalArchives of Oral Biology
Volume53
Issue number2
DOIs
StatePublished - Feb 1 2008

Fingerprint

Bite Force
Jaw
Human Activities
Tooth
Electromyography
Muscles
Pterygoid Muscles
Masseter Muscle
Cheek
Tongue
Linear Models
Analysis of Variance
Healthy Volunteers
Electrodes
Regression Analysis

Keywords

  • Bite force
  • EMG
  • Human
  • Jaw muscle

ASJC Scopus subject areas

  • Dentistry(all)

Cite this

Uchida, S., Iwasaki, L. R., Marx, D. B., Yotsui, Y., Inoue, H., & Nickel, J. C. (2008). Variations in activities of human jaw muscles depend on tooth-tipping moments. Archives of Oral Biology, 53(2), 199-205. https://doi.org/10.1016/j.archoralbio.2007.10.002

Variations in activities of human jaw muscles depend on tooth-tipping moments. / Uchida, S.; Iwasaki, L. R.; Marx, David B; Yotsui, Y.; Inoue, H.; Nickel, J. C.

In: Archives of Oral Biology, Vol. 53, No. 2, 01.02.2008, p. 199-205.

Research output: Contribution to journalArticle

Uchida, S, Iwasaki, LR, Marx, DB, Yotsui, Y, Inoue, H & Nickel, JC 2008, 'Variations in activities of human jaw muscles depend on tooth-tipping moments', Archives of Oral Biology, vol. 53, no. 2, pp. 199-205. https://doi.org/10.1016/j.archoralbio.2007.10.002
Uchida, S. ; Iwasaki, L. R. ; Marx, David B ; Yotsui, Y. ; Inoue, H. ; Nickel, J. C. / Variations in activities of human jaw muscles depend on tooth-tipping moments. In: Archives of Oral Biology. 2008 ; Vol. 53, No. 2. pp. 199-205.
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