Facial-Parameter TMJ Condylar Envelope Modeling for Prosthesis Motion
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Solution Overview
Problem
Existing artificial temporomandibular joint (TMJ) prostheses fail to accurately replicate the natural condylar movement envelope surface, leading to inadequate postoperative mandibular movement and potential damage to the natural joint, especially in cases of unilateral TMJR, due to the inability to directly obtain condylar movement envelope surface data.
Innovation Solution
A method and device for generating the condylar movement envelope surface of the TMJ based on facial parameters, involving the measurement of craniofacial features and parameters, construction of a matrix, and generation of cross-sectional curves using inverse operations to create an accurate condylar movement envelope surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If artificial TMJ prostheses are designed with reference to large joints (ball-socket relationship), then the morphological constraints of the articular fossa prosthesis on the articular process prosthesis are increased and dislocation is prevented, but the postoperative TMJ movement is restricted and cannot achieve normal mouth opening and lateral movement
Solution Approach 1:
The invention changes the design parameters of the artificial TMJ prosthesis from traditional ball-socket geometry to a morphology that replicates the natural condylar movement envelope surface. By using medical imaging to obtain the patient's specific condylar movement trajectory and constructing a custom envelope surface model, the prosthesis geometry is optimized to allow physiological movement ranges while maintaining stability, thus resolving the contradiction between dislocation prevention and movement range.
Solution Approach 2:
The invention copies the natural condylar movement envelope surface morphology from healthy individuals or the patient's own pre-disease state. By reconstructing the envelope surface based on medical imaging data and movement trajectory analysis, the artificial prosthesis replicates the complex curved geometry of the natural joint, enabling physiological movement patterns that simple ball-socket designs cannot achieve.
2Stability of the object's composition
If total joint prostheses are designed with reference to the bony structure of the normal TMJ, then the structural integrity is maintained, but the function of the articular disc cannot be simulated and joint movement function is not fully restored
Solution Approach 1:
The invention changes the design approach from static bony structure replication to dynamic movement envelope surface reconstruction. By analyzing the condylar movement trajectory and constructing the envelope surface that encompasses all physiological positions, the prosthesis design incorporates functional parameters that reflect the dynamic interaction between the condyle and articular disc, enabling restored joint movement function while maintaining structural integrity.
Solution Approach 2:
The invention performs preliminary analysis of the patient's condylar movement trajectory using medical imaging before prosthesis design. By obtaining the movement envelope surface data in advance and using it to guide the prosthesis geometry construction, the design process anticipates functional requirements and incorporates them into the structural design, ensuring both integrity and restored movement function.
3Reliability
If unilateral TMJR is performed, then the affected joint is replaced, but the inconsistent joint movement places greater force on the natural TMJ and causes potential damage
Solution Approach 1:
The invention changes the prosthetic joint parameters to match the patient's natural condylar movement envelope surface characteristics. By customizing the prosthesis geometry based on the patient's specific movement trajectory obtained through medical imaging, the prosthetic joint achieves movement consistency with the natural side, balancing the occlusal forces and reducing harmful asymmetric loading on the natural TMJ.
Data Source
AI summary
The present disclosure relates to a method and device for generating a condylar movement envelope surface of a TMJ and its cross-sectional curves based on facial parameters. In the method, reference facial parameters of a TMJ of a healthy person are measured, a matrix is generated based on the reference facial parameters and a reference cross-sectional curve equation of the condylar movement envelope surface, and then a target cross-sectional curve of a specific cross-section of a target condylar movement envelope surface is generated with the matrix and the target facial parameters. Furthermore, a target condylar movement envelope surface may be generated based on a plurality of the target cross-sectional curves.