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The jaw open-close movements predicted by biomechanical modelling
1Department of Functional Anatomy, Academic Centre for Dentistry Amsterdam (ACTA), The Netherlands.
Journal of Biomechanics
|September 26, 1997
Summary
This study modeled human jaw movements, revealing that specific muscle activations control opening and closing. Joint stabilization relies on muscle torques, with their line of action direction distinguishing opening from closing.
Area of Science:
- Biomechanics
- Human Physiology
- Mathematical Modeling
Background:
- Understanding human jaw movement mechanics is crucial for diagnosing and treating temporomandibular joint disorders.
- Previous models often simplified the complex interplay of muscles and joint dynamics.
Purpose of the Study:
- To analyze unloaded human jaw-opening and jaw-closing movements using a dynamic mathematical model.
- To investigate the influence of muscle activation patterns on jaw kinematics and joint loading.
Main Methods:
- Developed a 6-degree-of-freedom dynamical mathematical model of the human masticatory system.
- Incorporated detailed morphology, muscle architecture, and muscle properties into the model.
- Simulated symmetrical jaw movements under various muscle activation schemes.
Main Results:
- Jaw-opening swing and slide depend on digastric and inferior lateral pterygoid muscle activation.
- Temporalis muscle activation is critical for jaw-closing movements.
- Passive jaw-closing muscle forces limit jaw opening; jaw-opening muscle forces have negligible effect on closing.
Conclusions:
- Muscle activation levels critically determine jaw movement direction and extent.
- Jaw muscles generate torques responsible for temporomandibular joint stabilization during movement.
- The opposing lines of action of jaw muscles differentiate opening from closing movements.