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Jaw clenching: muscle and joint forces, optimization strategies
H J Schindler1, S Rues, J C Türp
1Research Group Biomechanics, Faculty for Mathematics, University of Karlsruhe, D-76128, Karlsruhe, Germany. myo.schindler@t-online.de
Journal of Dental Research
|August 28, 2007
Summary
Understanding jaw clenching forces is crucial. The medial pterygoid muscle and temporomandibular joints experience the highest loads during horizontal biting, not vertical biting.
Area of Science:
- Biomechanics
- Craniofacial anatomy
- Musculoskeletal system
Background:
- Forces generated by masticatory muscles and the temporomandibular joint (TMJ) during jaw clenching are not well understood.
- Accurate force estimations are essential for understanding jaw function and dysfunction.
Purpose of the Study:
- To determine the clenching directions that impose the greatest loads on masticatory muscles and the temporomandibular joints.
- To investigate potential motor control strategies during jaw clenching.
Main Methods:
- Utilized feedback-controlled electromyograms of all jaw muscles.
- Incorporated lines of action, skull geometry, and physiological cross-sectional areas from individual subjects.
- Applied objective functions to identify motor control strategies.
Main Results:
- The medial pterygoid muscle was the most heavily loaded muscle across all bite directions.
- Biting with significant horizontal force components resulted in the highest loading of the medial and lateral pterygoids.
- These horizontal biting directions also produced the largest temporomandibular joint forces, while vertical biting yielded the lowest.
Conclusions:
- Horizontal biting components significantly increase masticatory muscle and temporomandibular joint loading.
- The medial pterygoid is consistently the most loaded muscle during jaw clenching.
- Elastic energy optimization strategies align well with the calculated biomechanical results.
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