A three-dimensional mathematical model of temporomandibular joint loading

Area of Science:

• Biomechanics
• Biomedical Engineering
• Computational Modeling

Background:

• Direct measurement of human temporomandibular joint (TMJ) loading is challenging.
• Previous reliance on animal models, including primates, showed limitations in accuracy for human TMJ studies.
• Mathematical modeling offers a viable alternative for investigating TMJ biomechanics.

Purpose of the Study:

• To develop a three-dimensional mathematical model of the temporomandibular joint (TMJ).
• To analyze the magnitude and direction of compressive forces on the TMJ during clenching.
• To compare TMJ loading in healthy individuals versus those with TMJ disorders.

Main Methods:

• Utilized principles of static equilibrium in a 3D mathematical model.
• Integrated electromyography (EMG) data of masticatory muscles with their cross-sectional areas to determine muscle forces.
• Employed quadratic programming to solve for compressive forces on the TMJ, evaluating objective functions for predictive accuracy.

Main Results:

• Maximum bite forces: normal males (300 N), normal females (210 N), females with TMJ disorders (120 N).
• Calculated TMJ compressive forces: normal males (260 N), normal females (172 N), females with TMJ disorders (152 N).
• Demonstrated reduced bite and TMJ forces in individuals with TMJ disorders.

Conclusions:

• The developed mathematical model effectively estimates temporomandibular joint (TMJ) loading.
• Findings highlight significant differences in TMJ forces related to sex and TMJ disorder status.
• The model provides valuable insights into the biomechanics of the TMJ and the impact of disorders.