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Patient-Specific TMJ Implants: A Finite Element Study on Placement and Material Effects

Authors :

Aryana Tavakoulnia¹ Mohadese Rajaeirad² Nima Jamshidi³ Sandipan Roy⁴

1- University of Isfahan 2- University of Isfahan 3- University of Isfahan 4- SRM institute of technology

Keywords :

Temporomandibular Joint،Finite Element Analysis،Patient-Specific Prosthesis،Stress Distribution،PEEK،Titanium

Abstract :

The clinical success and long-term durability of total temporomandibular joint (TMJ) prostheses are directly dependent on mechanical stability and the pattern of biomechanical force distribution between the prosthesis and the host bone. Factors such as precise implant positioning and the mechanical properties of the prosthesis material play a critical role in its performance. This computational study aims to quantitatively and comparatively investigate the effect of the prosthesis's positioning and material on stress distribution and mechanical stability using the finite element method. A 3D model of a patient's mandible was reconstructed from high-resolution CT scans, and a patient-specific total joint prosthesis was designed. Two materials were considered: Titanium alloy (Ti-6Al-4V) and Polyetheretherketone (PEEK). For each material, three positioning scenarios were defined: (1) an ideal anatomical reference position, (2) a 2 mm lateral displacement, and (3) a 3 mm medial displacement. The bone-prosthesis assemblies were analyzed in Abaqus under a static chewing load of 262.28 N. The results showed that prosthesis positioning significantly impacts the stress distribution pattern. For the titanium model, the lateral position was identified as biomechanically optimal, as it best protected the host bone from excessive loading while ensuring maximum structural stability. A comparison of materials revealed that while titanium prostheses offer greater stability (less displacement), PEEK prostheses, due to an elastic modulus closer to that of bone, reduce the stress shielding phenomenon and lead to a more physiological load distribution on the bone. The final choice of material depends on prioritizing maximum stability versus the long-term health of the host bone.