Diagnostic group differences in temporomandibular joint energy densities

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

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Objectives: Cartilage fatigue, due to mechanical work, may account for precocious development of degenerative joint disease in the temporomandibular joint (TMJ). This study compared energy densities (mJ/mm3) in TMJs of three diagnostic groups. Setting and Sample Population: Sixty-eight subjects (44 women, 24 men) gave informed consent. Diagnostic criteria for temporomandibular disorders (DC/TMD) and imaging were used to group subjects according to presence of jaw muscle or joint pain (+P) and bilateral disk displacement (+DD). Material and Methods: Subjects (+P+DD, n = 16; -P+DD, n = 16; and -P-DD, n = 36) provided cone-beam computed tomography and magnetic resonance images, and jaw-tracking data. Numerical modeling was used to determine TMJ loads (Fnormal). Dynamic stereometry was used to characterize individual-specific data of stress-field dynamics during 10 symmetrical jaw-closing cycles. These data were used to estimate tractional forces (Ftraction). Energy densities were then calculated as W/Q (W = work done or mechanical energy input=tractional force × distance of stress-field translation, Q = volume of cartilage). anova and Tukey-Kramer post hoc analyses tested for intergroup differences. Results: Mean ± standard error energy density for the +P+DD group was 12.7 ± 1.5 mJ/mm3 and significantly greater (all adjusted p < 0.04) when compared to -P+DD (7.4 ± 1.4 mJ/mm3) and -P-DD (5.8 ± 0.9 mJ/mm3) groups. Energy densities in -P+DD and -P-DD groups were not significantly different. Conclusion: Diagnostic group differences in energy densities suggest that mechanical work may be a unique mechanism, which contributes to cartilage fatigue in subjects with pain and disk displacement.

Original languageEnglish (US)
Pages (from-to)164-169
Number of pages6
JournalOrthodontics and Craniofacial Research
Issue numberS1
StatePublished - Apr 1 2015
Externally publishedYes


  • Cartilage
  • Fatigue
  • Human
  • Mechanics
  • Temporomandibular joint

ASJC Scopus subject areas

  • Orthodontics
  • Surgery
  • Oral Surgery
  • Otorhinolaryngology


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