Human temporomandibular joint disc cartilage as a poroelastic material.

OBJECTIVE The hypothesis was tested that a poroelastic material model is potentially able to describe the mechanical behavior of cartilaginous tissues in dynamic indentation experiments.Design. This hypothesis was tested by comparing the results from model predictions with results obtained from cyclic indentation experiments. BACKGROUND The characteristics of cartilaginous tissues in general and of the temporomandibular joint disc in particular are generally identified by static confined or unconfined indentation experiments, while under physiologic circumstances these tissues are mostly loaded dynamically. METHODS Dynamic indentation experiments were simulated using an axisymmetric finite element model. The results from the simulations were qualitatively compared with the experiments. RESULTS The simulations showed several similarities with the experiments when the solid matrix was assumed to be hyperelastic. Both the maximum stress and the amount of energy dissipated decreased in each subsequent cycle. Furthermore, a similar dependency on the indentation frequency and amplitude was found. CONCLUSIONS This qualitative study showed that a poroelastic material model can describe the dynamic behavior of the temporomandibular joint disc, provided that the solid matrix is modeled as hyperelastic. RELEVANCE Temporomandibular disorders are presumably related to joint load distributions. Besides large static, dynamic loads are considered as a risk factor for cartilaginous wear. Dynamical loads, however, are also considered to stimulate the biosynthetic activity of cartilaginous tissues. Biomechanical analysis can be applied to estimate nonmeasurable joint loads. This enables to understand the underlying mechanisms of temporomandibular disorders, necessary to develop methods to prevent, diagnose and cure joint disorders. The present study shows that a poroelastic material model can be applied successfully to model the dynamical behavior of the temporomandibular joint disc in such analyses.