Human jaw and muscle modelling.

Dynamic mathematical modelling is an invaluable method to help understand the biomechanics of the anatomically and functionally complex masticatory system. It provides insight into variables which are impossible to measure directly such as joint loads and individual muscle tensions, and into physical relationships between jaw structure and function. Individual parameters can be modified easily to understand their influence on function. Our models are constructed with best available structural and functional data, and evaluated against human jaw behaviour. Image data provide hard and soft tissue morphology and the jaw's inertial properties. The drive to the system is provided by actuators which simulate active and passive jaw muscle properties. In whole-jaw modelling, muscle models which behave plausibly rather than mimic the ultra-structural cross-bridge interactions are common since they are computationally feasible. Whole-jaw models have recently incorporated flexible finite-elements to explore tissue distortion in the temporomandibular joint and tongue movements. Furthermore, the jaw has been integrated with laryngeal models to explore complex tasks such as swallowing. These dynamic models have helped better understand joint loading, movement constraints and muscle activation strategies. Future directions will include further incorporation of rigid and flexible model dynamics and the creation of subject-specific models to better understand the functional implications of pathology.