Quasi-Linear Viscoelastic Model of the Articular Disc of the Temporomandibular Joint

Abstract

A precise characterization of the articular disc of the temporomandibular joint (TMJ) is essential to study the masticatory biomechanics. The disc is responsible for the load distribution over the articular surface and for absorbing impacts during mastication. The main objective of this work is to characterize the mechanical behaviour of the articular disc under compression, the usual stress state during mastication. A quasi-linear viscoelastic (QLV) model, with a hyperelastic response for the elastic function, is proposed to describe the mechanical behaviour of the articular disc. The validity of that simplified model relies on the independence of their constants with the strain level and strain rate. The independence of the strain level was proved in a previous work. In this paper, different loading rates were tested to fully confirm the validity of the model in the physiological range of loads. Moreover, the strong non-linearity of the stress-strain relation made the exponential strain energy function the most suitable of the different models tried to represent the elastic response of the QLV model.