Temporo-mandibular Prosthesis with Polymeric Glenoid Insert
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Solution Overview
Problem
Conventional temporo-mandibular joint prostheses face challenges in avoiding metallic particle release due to metal-metal contact between the glenoid and condylar parts, while requiring precise fixation for efficient articulation.
Innovation Solution
A temporo-mandibular prosthesis using a polymeric glenoid insert with a metallic glenoid support, where the glenoid insert is fixed after both parts are anchored to the temporal bone and mandible, utilizing a deformable tab for easy immobilization and precise fitting, preventing metal-metal friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal-metal contact is used between glenoid part and condylar part, then efficient and compact fixation is achieved, but metallic particles are released in the patient
Solution Approach 1:
A polymeric insert is introduced as an intermediary element between the metallic glenoid support and the condylar part. This insert acts as a mediator that prevents direct metal-metal contact while maintaining the articulation function, thereby eliminating metallic particle release while preserving fixation efficiency.
Solution Approach 2:
The prosthesis employs a composite material structure combining metallic components (glenoid support, condylar part) with a polymeric insert. This composite approach allows the metal parts to provide structural strength and fixation while the polymer provides a non-wearing, non-corrosive articulating surface that prevents particle generation.
2Ease of manufacture
If glenoid insert is fixed before anchoring parts, then assembly is simplified, but precise fitting between insert and condylar part cannot be ensured
Solution Approach 1:
The metallic glenoid support and condylar part are anchored to the bone structures first as preliminary actions. This establishes a stable reference framework that allows the polymeric insert to be precisely positioned and fitted afterward, ensuring optimal articulation while maintaining assembly simplicity.
Solution Approach 2:
The prosthesis is divided into separable components: the metallic glenoid support anchored to temporal bone, the condylar part anchored to mandible, and the polymeric insert positioned between them. This segmentation allows independent positioning and precise fitting of each component before final assembly.
3Reliability
If complex fixation method is used for glenoid insert, then secure immobilization is achieved, but assembly procedure becomes complicated
Solution Approach 1:
The polymeric insert is designed to be self-retaining through friction fit and geometric interlocking with the glenoid support. The insert's shape and material properties enable it to maintain its position and provide secure immobilization without requiring additional complex fixation mechanisms or multiple assembly steps.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures precise and efficient fixation without metallic particle release, allowing for easy adaptation and definitive fixation of the glenoid insert, ensuring a perfect fit and preventing metallic particle release in the patient's mouth.
Implementation Method 1
a simple change of the position of the tab
Data Source
Figure 1~2
AI summary
The present invention relates to a temporo-mandibular prosthesis comprising a glenoid part (12) and a condylar part (14) intended to be articulated relative to the glenoid part, said glenoid part comprising: - a glenoid support (18) made in a metallic material; and - a glenoid insert (20) made in a non-metallic material, and defining a seat for a head of said condylar part to define said articulation, wherein the glenoid support defines a housing (26) having an opening (28) through which said glenoid insert is insertable into said housing, said opening opening on an external side (E) of said glenoid support, the glenoid support comprising a tab (40) configurable in a passive position and in an active position in which said tab allows and forbids, respectively, the insertion and the extraction, respectively, of said glenoid insert into and out of said housing, respectively.