Biomechanical analysis of a temporomandibular joint prosthesis for lateral pterygoid muscle reattachment.

OBJECTIVE:To analyze the biomechanical properties of a novel temporomandibular joint (TMJ) prosthesis with an attachment area for the lateral pterygoid muscle (LPM). STUDY DESIGN:Three prosthesis models were created and compared using finite element analysis for the displacement, stress, and strain when simulating the maximum bite force loading. A verification experiment and a compression test were conducted. RESULTS:The displacement, stress, and strain of the novel TMJ prosthesis were larger than the solid condylar neck prosthesis and similar to the slotted condylar neck prosthesis, but the values were far less than the yield strength of titanium alloy. The maximum stress and strain in the novel TMJ prosthesis was concentrated in the inner and boundary areas of the LPM reattachment region beside the thinnest part of the prosthesis neck. The difference in the strain values measured using the verification test and those using finite element analysis was <20%. Compression testing of the novel TMJ prosthesis revealed that the mandible fractured when the force reached 588.97 N, whereas the prosthesis itself did not break or deform. CONCLUSIONS:The mechanical distribution of the novel prosthesis was feasible under maximum bite force for potential clinical application.