2.2.3. Material Properties

Young's modulus and Poissson's ratio of anatomical components (fossa and mandible bone with teeth), titanium alloy (for condylar component and all screws), and UHMWPE (for fossa component) were selected as listed in Table 3. All anatomical components of the model (i.e., cortical bone, cancellous bone, and teeth) were assigned properties of the cortical bone similar to other researchers [27,28] who have previously followed this practice since variation in material properties of these components have negligible influence on biomechanics of the mandible. All materials used in FE models were assumed to be isotropic, homogeneous, and linearly elastic [26]. Static FE simulations were performed using ABAQUS software. Three repetitions/runs of FE simulation under each loading condition were performed for both types of total TMJ implants to account for any userinduced errors such as variation in selecting exactly the same nodes of FE mesh across different simulations. The results summarized in Tables 4 and 5 are average of three simulations for each loading condition for both types of total TMJ prosthesis.


**Table 3.** Material properties for anatomical and prosthetic TMJ components.

**Table 4.** Peak von Mises stresses developed in condyle/ramus and fossa components, and fixation screws of the simple and notched designs of patient-specific total TMJ prostheses during FE simulations under normal and worst-case/over–loading configurations.


\* Average of three simulations performed under similar constraints and loading at three different times (to account for variations induced by the user/operator).

**Table 5.** Peak stress and strain developed in host bone surrounding the fixation screws of the simple and notched designs of patient-specific total TMJ prostheses during FE simulations under normal and worst-case/over-loading configurations.


\* Average of three simulations performed under similar constraints and loading at three different times (to account for variations induced by the user/operator).
