Gradient Modulus Plastic Dental Implant
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Solution Overview
Problem
High-modulus plastics used for implants, such as dental implants, often lead to the stress-shielding effect, where the bone loses density and strength due to lack of physiological stress stimulation, as they are too stiff for the bone structure.
Innovation Solution
A composite implant semi-finished product made of thermoplastic units with a modulus of elasticity gradient, where a biocompatible plastic with a lower modulus is seamlessly connected to a higher modulus plastic using thermal joining, creating a transition zone that mimics the natural elasticity of bone, thereby reducing stress-shielding and ensuring mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-modulus plastic materials are used for implants, then mechanical strength is improved, but stress-shielding effect occurs causing bone density loss
Solution Approach 1:
The implant is divided into multiple sections with different modulus of elasticity values. The distal portion has a lower modulus (1-10 GPa) to transmit physiological stress to the bone, while the proximal portion has a higher modulus (10-50 GPa) to provide mechanical strength and stability. This segmentation allows each portion to fulfill its specific function without causing stress-shielding.
Solution Approach 2:
Different portions of the implant are assigned different material properties tailored to their specific functional requirements. The distal portion near the bone interface uses material with lower modulus to maintain bone health, while the proximal portion uses higher modulus material for structural support. This local differentiation of material properties resolves the contradiction between strength and stress-shielding.
2Stability of the object's composition
If stiff materials like titanium are used, then mechanical stability is improved, but bone adaptation and density maintenance deteriorate
Solution Approach 1:
The implant structure is segmented into proximal and distal portions with different stiffness characteristics. The distal portion with lower modulus allows bone adaptation and physiological stress transmission, while the proximal portion provides the necessary mechanical stability for load-bearing functions.
Solution Approach 2:
The modulus of elasticity parameter is varied along the length of the implant. By changing this physical parameter from high in the proximal portion to low in the distal portion, the implant achieves both mechanical stability and bone adaptability, preventing bone resorption while maintaining structural integrity.
3Strength
If fiber-reinforced plastics are used, then mechanical requirements are improved, but modulus of elasticity becomes too high for bone compatibility
Solution Approach 1:
The implant uses fiber-reinforced plastic material only in the proximal portion where high mechanical strength is required for stability. The distal portion uses non-reinforced or less reinforced material with lower modulus to maintain bone compatibility. This spatial segmentation of reinforcement allows simultaneous achievement of mechanical requirements and bone compatibility.
Solution Approach 2:
Fiber reinforcement is applied locally only where mechanically necessary. The proximal portion receives fiber reinforcement for high strength, while the distal portion maintains lower reinforcement levels for bone compatibility. This local differentiation of material composition resolves the contradiction between mechanical requirements and bone adaptability.
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
The composite implant design effectively reduces stress-shielding, maintains bone health by simulating natural stress, and provides sufficient mechanical strength for secure attachment of further components, such as screws, while optimizing aesthetics and mechanical properties.
Implementation Method 1
at least one biocompatible (first) thermoplastic plastics unit (A) intended for contact with a biological material and having a modulus of elasticity EA and at least one (second) thermoplastic plastics unit (B) with a modulus of elasticity EB, wherein the moduli of elasticity of these plastics units EA < EB
Data Source
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AI summary
The invention relates to an implant semifinished good made of plastic, which implant semifinished good comprises a composite. Said composite is composed of at least one biocompatible thermoplastic plastic unit (A), which is intended for contact with a biological material and has a modulus of elasticity EA, and at least one thermoplastic plastic unit (B), which has a modulus of elasticity EB. EA < EB applies to the moduli of elasticity of said plastic units. The plastic units are thermally connected to each other in a seamless manner in a connection zone of the plastic units. The invention further relates to the production of the implant semifinished good made of plastic and the use of the implant semifinished good as an implant or to produce an implant therefrom, in particular the use of the implant semifinished good as a dental implant or to produce a dental implant. The invention can also be applied to other bone implants.