Dental Composition Color Stability Using Bisacylphosphine Oxide
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Solution Overview
Problem
Current dental materials using visible light-photopolymerization initiators, such as a-diketone and amine compounds, suffer from significant color tone changes before and after curing, leading to poor aesthetic compatibility and reduced usability, while (bis)acylphosphine oxide compounds exhibit limited wavelength range compatibility and yellowing issues.
Innovation Solution
A visible light-polymerizable dental composition that excludes amine compounds, utilizing a combination of (bis)acylphosphine oxide and a-diketone compounds, specifically 2,4,6-trimethylbenzoyldiphenylphosphine oxide and camphorquinone, with a polymerizable monomer like dipentaerythritol hexaacrylate, which maintains color tone stability and exhibits excellent photopolymerizability across a wide wavelength range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If amine compounds are used as photopolymerization initiators, then photopolymerizability is improved, but color tone changes drastically and yellowing occurs
Solution Approach 1:
The invention extracts and removes the amine compound component from the photopolymerization initiator system. By using only (bis)acylphosphine oxide compounds without amine compounds, the patent eliminates the source of yellowing and color tone changes while maintaining photopolymerization capability through alternative initiator chemistry.
Solution Approach 2:
The invention changes the chemical composition parameters of the photopolymerization initiator system by substituting amine compounds with (bis)acylphosphine oxide compounds. This parameter change in initiator chemistry fundamentally alters the photopolymerization mechanism to avoid yellowing while maintaining curing efficiency.
2Object-generated harmful factors
If (bis)acylphosphine oxide compounds are used, then yellowing is reduced and internal curability is improved, but curing does not occur with narrow wavelength range light sources
Solution Approach 1:
The invention creates a composite photopolymerization initiator system combining (bis)acylphosphine oxide compounds with specific polymerizable monomers and fillers. This composite formulation optimizes the absorption characteristics and extends the effective wavelength range while maintaining the low yellowing properties of (bis)acylphosphine oxide compounds.
3Speed
If conventional visible light photopolymerization initiators are used, then curing speed is improved, but color tone compatibility with natural teeth deteriorates
Solution Approach 1:
The invention converts the typically harmful yellowing effect into a beneficial aesthetic property. By using (bis)acylphosphine oxide compounds that produce minimal yellowing, the cured dental material achieves a color tone that closely matches natural teeth, transforming what was previously a defect into an aesthetic advantage while maintaining adequate curing speed.
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 composition achieves minimal color tone change before and after curing, improved thin-layer surface curability, and extended usability, suitable for dental fillers, adhesives, and restorative materials, with enhanced compatibility across various light sources.
Implementation Method 1
A visible light-polymerizable dental composition which does not substantially contain an amine compound as a photosensitizer, comprising 0.01 to 10 parts by weight of a (bis)acylphosphine oxide compound, 0.01 to 10 parts by weight of an a-diketone compound and 100 parts by weight of a polymerizable monomer
Data Source
AI summary
An object of the present invention is to provide a photopolymerizable dental composition which causes less change in a color tone before and after curing and exhibits excellent photopolymerizability to irradiation in a wide wavelength range, and has also excellent thin-layer surface curability, and to provide a photopolymerization initiator used therefor.Disclosed is a visible light-polymerizable dental composition which does not substantially contain an amine compound as a photosensitizer, comprising 0.01 to 10 parts by weight of a (bis)acylphosphine oxide compound, 0.01 to 10 parts by weight of an α-diketone compound and 100 parts by weight of a polymerizable monomer.