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Updated: May 28, 2026

A Morphometric and Cellular Analysis Method for the Murine Mandibular Condyle
Published on: January 11, 2018
Dynamic Mechanics and Longitudinal Changes in Temporomandibular Joint Structural Integrity
Jeff C Nickel1,2, Luigi M Gallo3, Yoly M Gonzalez2
1Department of Oral and Craniofacial Sciences, School of Dentistry, Oregon Health & Science University, Portland, Oregon, USA.
Background:
Longitudinal changes in temporomandibular joint (TMJ) structures may reflect joint contact mechanics and jaw loading behaviours (Mechanobehaviour Score, MBS).
Objective:
Test if baseline MBS correlates with longitudinal changes in TMJ structures.
Methods:
According to Institutional Review Board oversight, diagnoses of adult subjects at baseline and follow-up were determined by Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) via clinical examination, cone-beam computed tomography and magnetic resonance imaging. At baseline, subjects recorded in-field jaw muscle electromyography to calculate diurnal and nocturnal muscle duty factors (DF, %) and TMJ energy densities (ED, mJ/mm3) during jaw closing were estimated using computer-modelled joint loads and dynamic stereometry. These data were combined to produce baseline MBS (ED2●DF, (mJ/mm3)2%). General linear hypothesis, Tukey's Honest Significant Difference, and machine learning models tested MBS and component variables for baseline vs. follow-up differences in groups where TMJ integrity stayed the same (Group A), got better (Group B), or got worse (Group C).
Results:
Forty-three subjects (29 female, 14 males) participated. The average time between baseline and follow-up was 8.0 ± 2.5 years. Analyses of 85 TMJs (43 right, 42 left) showed significantly smaller MBS (all p < 0.002) for Group B (n = 18; 71 ± 6 (mJ/mm3)2%) than Group A (n = 42; 197 ± 7 (mJ/mm3)2%) and Group C (n = 25; 650 ± 24 (mJ/mm3)2%). Group prediction accuracy by machine learning modelling was 0.96 (sensitivity, 0.98; specificity, 0.92) for the combination of TMJ stress-field aspect ratio, cartilage volume under the leading edge of the translating stress-field, stress-field translation distance, and velocity of stress-field translation.
Conclusion:
Mechanobehaviour variables accurately predicted changes in TMJ integrity.
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