Figure 3: Distribution map of the maximal principal stress (a) and the minimal principal stress (b) in the TMJ with orthotropic properties. The pictures show us that the stress uniformly transferred from the surface to the central part of the orthotropic condyle. Stress of the anterior part of the TMJ was mainly compressive and that of posterior part was mainly tensile (the cartilage could not be seen clearly from this direction). Comparisons of the maximal principle stress and the minimal principle stress in TMJ between the finite element analysis model with an orthotropic condyle and isotropic condyle were marked in (c) and (d), in which black curve corresponded with data based on the orthotropic model and the multicolored curve with data based on the isotropic model. It showed that stress values in the condylar neck (point 1, 2), condyle (points 3–11), and cartilage (points 12–20) of the isotropic model were higher than those of the orthotropic model (with ** indicating and * indicating ), whereas values in the disc of the both models showed no differences (points 20–29).