Dental Prosthesis Support Structure Undercut Retention Elements
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Solution Overview
Problem
Existing dental prosthesis supporting structures fail to achieve a strong bond between the supporting structure and the upper synthetic or porcelain structure, limiting the durability and reliability of the connection.
Innovation Solution
A method involving digital design and manufacturing using Selective Laser Powder Processing to create a surface texture with retention elements, such as protrusions and recesses with undercuts, on the nominal surface of the supporting structure, enhancing the contact area and adhesive power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the surface roughness is increased by sandblasting or plasma treatment to enlarge the contact surface, then the bond strength between supporting structure and upper structure is improved, but the manufacturing complexity and process steps are increased
Solution Approach 1:
The retention elements with undercuts are integrated into the supporting structure design from the beginning, allowing the bond strength enhancement to be achieved through the structure itself rather than requiring subsequent surface treatment steps like sandblasting or plasma treatment
Solution Approach 2:
The function of creating retention elements and the function of forming the supporting structure are merged into a single manufacturing process (selective laser melting), eliminating the need for separate surface treatment operations
2Strength
If a porous top coat is provided on the supporting structure to enhance bonding, then the adhesive power is improved, but the manufacturing precision and structural control are reduced
Solution Approach 1:
The mechanical porous top coat layer is replaced by digitally designed retention elements with precise undercut geometries, allowing for controlled and repeatable structural features that provide mechanical interlocking without requiring additional coating processes
Solution Approach 2:
The surface characteristics are changed from a porous coating layer to defined geometric retention elements with specific dimensions, shapes, and undercut parameters that are precisely controlled through digital modeling
3Ease of manufacture
If granular retention elements are created through lost wax technique, then the surface texture is formed, but the bond strength is insufficient compared to undercut retention elements
Solution Approach 1:
The geometry of retention elements is changed from simple granular protrusions to elements with undercut features, where the undercut parameter (negative slope relative to the nominal surface) provides mechanical interlocking that significantly enhances bond strength while maintaining manufacturability through selective laser melting
4Strength
If the contact surface area is enlarged by increasing surface roughness, then the bond strength is improved, but the amount of material and weight are increased
Solution Approach 1:
Instead of uniformly increasing surface roughness across the entire supporting structure, retention elements with undercuts are placed locally at specific positions where bonding is required, providing enhanced bond strength only where needed without adding unnecessary material and weight throughout the entire structure
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 method significantly improves the bond strength between the supporting structure and the upper structure, ensuring a more reliable and durable connection by increasing the contact surface area through the use of retention elements with undercuts, specifically designed and manufactured using rapid prototyping techniques.
Implementation Method 1
the supporting structure is made by means of a selective laser sintering and melting method, in particular Selective Laser Powder Processing
Implementation Method 2
a selective laser sintering and melting method is applied as said rapid prototyping technique, in particular a Selective Laser Powder Processing
Data Source
Figure 1~2
Figure 3~7
AI summary
The invention concerns a supporting structure for a dental prosthesis and a method for producing this supporting structure, whereby this supporting structure (6) comprises means (7) to be fixed to at least one implant (4) and/or at least one tooth which is set into a person's jawbone, whereby the supporting structure (6) has a nominal surface (9) having a surface texture (8) which is at least partly formed of retention elements (12). Said retention elements retention elements (12) comprise protrusions and/or recesses in relation to said nominal surface (9) each having an undercut (13).