Muscle organization in individuals with and without pain and joint dysfunction

J. C. Nickel, Y. M. Gonzalez, W. D. McCall, R. Ohrba, D. B. Marx, H. Liu, L. R. Iwasaki

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Central nervous system organization of masticatory muscles determines the magnitude of joint and muscle forces. Validated computer-assisted models of neuromuscular organization during biting were used to determine organization in individuals with and without temporomandibular disorders (TMD). Ninety-one individuals (47 women, 44 men) were assigned to one of four diagnostic groups based on the presence (+) or absence (-) of pain (P) and bilateral temporomandibular joint disc displacement (DD). Electromyography and bite-forces were measured during right and left incisor and molar biting. Two three-dimensional models employing neuromuscular objectives of minimization of joint loads (MJL) or muscle effort (MME) simulated biting tasks. Evaluations of diagnostic group and gender effects on choice of best-fit model were by analysis of variance (ANOVA) and Tukey-Kramer post hoc tests, evaluations of right-left symmetry were by Chi-square and Fisher's exact statistics, and evaluations of model accuracy were by within-subject linear regressions. MME was the best-fit during left molar biting in +DD individuals and incisor biting in men (all p < 0.03). Incisor biting symmetry in muscle organization was significantly higher (p < 0.03) in healthy individuals compared with those with TMD. Within-subject regressions showed that best-fit model errors were similar among groups: 8 to 15% (0.68 ≤ R2 ≤ 0.74). These computer-assisted models predicted muscle organization during static biting in humans with and without TMDs.

Original languageEnglish (US)
Pages (from-to)568-573
Number of pages6
JournalJournal of dental research
Issue number6
StatePublished - Jun 2012
Externally publishedYes


  • biting
  • human
  • masticatory muscles
  • modeling
  • neuromuscular
  • temporomandibular disorders

ASJC Scopus subject areas

  • General Dentistry


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