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In situ Compressive Loading and Correlative Noninvasive Imaging of the Bone-periodontal Ligament-tooth Fibrous Joint
Published on: March 7, 2014
Dynamic mechanics in the pig mandibular symphysis
G E J Langenbach1, F Zhang, S W Herring
1Department of Functional Anatomy, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam en Vrije Universiteit, The Netherlands.
Journal of Anatomy
|July 11, 2006
Summary
This study used a dynamic pig jaw model to simulate mastication forces and torques at the jaw symphysis. The model confirmed three loading patterns, revealing key biomechanical events during chewing.
Area of Science:
- Biomechanics
- Mammalian Jaw Function
- Computational Modeling
Background:
- Mastication involves complex biomechanical events at the mammalian jaw symphysis.
- Previous studies analyzed static conditions or surface bone strains, lacking direct measurement of dynamic forces and torques.
- Directly demonstrating forces and torques during dynamic muscle tension changes has been a challenge.
Purpose of the Study:
- To modify a dynamic pig jaw model to predict forces and torques at the symphysis.
- To correlate these forces and torques with simulated muscle tensions and other bite-related forces.
- To investigate dynamic loading patterns at the jaw symphysis during mastication.
Main Methods:
- A dynamic pig jaw model was modified with an artificial rigid joint at the symphysis.
- Tri-axial forces and torques at the symphysis were measured using the model.
- Simulated masticatory muscle tensions, bite, joint, and food bolus forces were incorporated.
Main Results:
- The model confirmed three previously postulated symphysis loading patterns: dorsoventral shear, medial transverse bending, and lateral transverse bending (wishboning).
- Dorsoventral shear correlated with balancing-side adductor forces and working-side bite reaction forces.
- Medial transverse bending was linked to lateral pterygoid tensions during jaw opening, while wishboning involved masseter actions during the power stroke.
Conclusions:
- Dynamic modeling provides a powerful method for studying jaw biomechanics, especially for in vivo unmeasurable parameters.
- The study identified specific muscle actions associated with distinct symphysis loading patterns during mastication.
- The largest predicted force was dorsoventral shear, and the largest torque was a 'wishboning' torque.
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