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Dynamics of the human masticatory system.
1Department of Functional Anatomy, Academic Centre for Dentistry Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands. j.h.koostra@amc.uva.nl
Summary
Muscles are the primary drivers of human jaw movement, dictating motion with six degrees of freedom. Biomechanical analysis reveals how muscle forces, jaw inertia, and joint forces determine masticatory system dynamics.
Area of Science:
- Biomechanics
- Human Anatomy
- Kinesiology
Background:
- The human masticatory system's complex movements are crucial for functions like eating and speaking.
- Understanding the biomechanical principles governing jaw motion is essential for diagnosing and treating related disorders.
Purpose of the Study:
- To review the movement characteristics of the human masticatory system from a biomechanical perspective.
- To analyze the forces and torques acting on the mandible to determine the primary drivers of jaw movement.
Main Methods:
- Application of the three fundamental laws of mechanics to the anatomical structures of the masticatory system.
- Analysis of forces and torques exerted by muscles, joints, articular capsules, and teeth on the mandible.
- Introduction of a principle relating forces to the center of gravity of the lower jaw.
Main Results:
- Muscles are identified as the dominant determinants of jaw movement, causing acceleration with six degrees of freedom.
- Jaw movement is influenced by the orientation of muscle lines of action relative to the mandible's center of gravity.
- Articular forces and passive structures like ligaments play significant roles, especially at movement boundaries and during asymmetric loading.
Conclusions:
- The biomechanics of the masticatory system are primarily governed by muscular forces, with passive structures contributing at extremes.
- Understanding these biomechanical determinants is key to comprehending normal and abnormal jaw function.