Self-Etching Dental Primer for Silicate Ceramics
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Solution Overview
Problem
Current dental primer compositions require separate etching and priming steps for silicate ceramic surfaces, which are time-consuming and labor-intensive, and often use toxic hydrofluoric acid, leading to structural damage and impaired bonding.
Innovation Solution
A self-etching primer composition containing alkoxysilane monomers and polyhydrogen fluoride salts that simultaneously etch and prime silicate ceramic surfaces, reducing the number of work steps and eliminating the need for hydrofluoric acid, while ensuring a stable and durable bond.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hydrofluoric acid is used for etching silicate ceramic surfaces, then a retentive surface structure is created that improves bonding, but the process causes structural damage to the ceramic and impairs bond strength
Solution Approach 1:
The invention changes the chemical parameters of the etching process by using polyhydrogen fluoride salts (such as ammonium bifluoride, tetrabutylammonium hydrogen difluoride, or tetrabutylammonium dihydrogen trifluoride) instead of hydrofluoric acid. These salts release fluoride ions that etch the ceramic surface to create micromechanical retention points, but with controlled reactivity that prevents over-etching and structural damage to the ceramic, thereby maintaining bond strength while achieving surface retentivity.
Solution Approach 2:
The invention introduces polyhydrogen fluoride salts as an intermediary substance that mediates between the need for effective etching and the need to preserve ceramic integrity. These salts serve as a safer, more controllable alternative to hydrofluoric acid, providing the necessary fluoride ions for etching while being less toxic and more manageable in terms of reaction control, thus resolving the contradiction between effective bonding and ceramic damage prevention.
2Manufacturing precision
If separate etching and priming steps are used, then thorough surface preparation is achieved, but the process becomes time-consuming and labor-intensive
Solution Approach 1:
The invention merges the etching and priming functions into a single dual-functional composition. The composition contains both polyhydrogen fluoride salts for etching and silane monomers for priming, allowing both surface preparation steps to be performed simultaneously in one application, thereby reducing processing time and labor requirements while maintaining thorough surface preparation quality.
Solution Approach 2:
The invention creates a universal primer composition that performs multiple functions: it etches the ceramic surface to create micromechanical retention, provides silane monomers for chemical bonding, and ensures proper surface preparation. This multi-functional composition eliminates the need for separate etching and priming steps, making the process more efficient without compromising surface preparation quality.
3Strength
If hydrofluoric acid is used for etching, then effective bonding is achieved, but the process introduces toxicity risks and requires careful control of concentration and exposure time
Solution Approach 1:
The invention converts the harmful properties of hydrofluoric acid into beneficial ones by using polyhydrogen fluoride salts. These salts release fluoride ions that provide the same etching capability for strong bonding, but in a safer, less toxic form that is easier to handle and control. The salts provide controlled fluoride ion release that achieves effective bonding without the severe toxicity and safety concerns associated with hydrofluoric acid.
Solution Approach 2:
The invention replaces the dangerous, long-lasting hazardous material (hydrofluoric acid) with safer, more controllable polyhydrogen fluoride salts that can be used and disposed of more safely. The salt-based etchants provide effective bonding capability without the persistent toxicity and environmental hazards of hydrofluoric acid, making them a more acceptable alternative despite requiring similar application precision.
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 primer composition achieves a strong, stable adhesive bond comparable to conventional methods, with improved thermal cycling resistance and reduced toxicity, allowing for faster and more efficient dental restoration procedures.
Implementation Method 1
The primer composition comprises (1) at least one alkoxysilane monomer of the general formula (I)... and (4) water... The alkoxysilane monomer reacts with water to form a crosslinked structure
Implementation Method 2
The roughening serves to create a micro-retentive surface structure... The method commonly used in dental technology for wet chemical erosion ('etching') of silicates primarily uses aqueous hydrofluoric acid solutions
Implementation Method 3
The polymerizable monomer units form a crosslinked structure... The polymerizable groups enable copolymerization with other monomers
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Primer formulation comprises: at least one alkoxysilane monomer (I); at least one polyhydrogenfluoride salt (II); an organic solvent and water. Primer formulation comprises: at least one alkoxysilane monomer of formula ((R1)nSi(OR2)4-n) (I); at least one polyhydrogenfluoride salt of formula ((R9)+>(Hx-1Fx)z->) (II); an organic solvent and water. R1 : an organic group containing at least one ethenylically unsaturated polymerizable group; R2 : 1-8C-alkyl; n : 1-3; R9 : a metal cation comprising alkali, alkaline earth metals, transition metals or an ammonium ion of formula ((R5)(R6)(R7)(R8)N+>) (AA); R5-R8 : H or 1-26C-alkyl, 3-26C-alkylene or 6-26C-aryl, where two of R5-R8 can be linked together with N to form a heterocycle, and three of R5-R8 can be linked together with N to form a pyridinium; x : 2-5, preferably 3; and z : valence of the cationic group R9. An independent claim is included for a dental restoration, where at least one part of its surface is treated with the primer formulation.