Polymerizable Dental Composition with Oxygen-Inhibition Control
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Solution Overview
Problem
Existing photoinitiator systems for dental compositions, such as camphorquinone and aromatic amines, pose safety concerns and have limitations in polymerization rate, tissue safety, and oxygen inhibition, leading to incomplete curing and potential tissue damage.
Innovation Solution
A polymerizable dental composition using a compound of formula (CQ-Ar) as an initiator, which provides high polymerization rates, tissue safety, and complete curing without causing toxic, inflammatory, allergic, or carcinogenic reactions, while minimizing oxygen inhibition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If camphorquinone and aromatic amines are used as photoinitiator system, then polymerization rate is sufficient for clinical use, but toxicity and safety concerns arise
Solution Approach 1:
The patent extracts and removes the harmful aromatic amine component from the photoinitiator system while retaining camphorquinone as the sole photoinitiator. This extraction eliminates the toxicity and safety concerns associated with aromatic amines while maintaining sufficient polymerization rate through optimized camphorquinone formulation and lighting conditions.
2Productivity
If high intensity light is used for rapid polymerization, then polymerization rate increases, but heat generation damages pulp tissue
Solution Approach 1:
The patent changes the parameters of the photoinitiator system by using camphorquinone with optimized concentration and characteristics that allow polymerization to proceed efficiently at lower light intensities. This parameter change reduces heat generation and prevents pulp tissue damage while maintaining adequate polymerization rate through extended exposure time or optimized formulation.
3Stability of the object's composition
If oxygen is present during polymerization, then composition is stable during storage, but polymerization is inhibited and curing is incomplete
Solution Approach 1:
The patent converts the harmful effect of oxygen inhibition into a beneficial feature by utilizing the controlled presence of oxygen to maintain stability during storage and handling. The camphorquinone-based system is formulated to achieve complete curing despite oxygen presence, turning the inhibition effect into a storage stability mechanism while ensuring reliable polymerization under controlled curing conditions.
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 compound achieves rapid polymerization within 30-40 seconds, ensures safe irradiation intensity, controls heat generation, and prevents incomplete curing, ensuring complete restoration polymerization without adverse health effects.
Implementation Method 1
the photoinitiator compound undergoes excitation by energy absorption with subsequent decomposition of the compound into one or more radicals (Norrish type I), or (2) the photoinitiator compound undergoes excitation and the excited photoinitiator compound interacts with a second compound by either energy transfer or a redox reaction to form free radicals
Implementation Method 2
free radical photocuring may be inhibited by the presence of oxygen. Oxygen inhibition is due to the rapid reaction of propagating radicals with oxygen molecules to yield peroxyl radicals which are not as reactive towards carbon-carbon unsaturated double bonds
Data Source
Figure 1~2
AI summary
A polymerizable composition comprising a mixture of (a) at least one polymerizable monomer having a polymerizable carbon-carbon double bond; (b) an initiator system comprising a compound of the following formula (I), or a salt thereof: CQ-Ar (I) wherein CQ is a group of the following formula (II) and Ar is a group of the following formula (III): wherein R1 represents a hydrogen atom, or a C1-6 alkyl group; R2 represents a hydrogen atom or a group CONR8-Ar', wherein R8 is a hydrogen atom, or a C1-6 alkyl group, and Ar' is independently a group of formula (III); R3, R4, R5, R6, and R7 which may be the same or different, are independently selected from a hydrogen atom, a C1-8 alkyl group, a nitro group, a cyano group, an amino group optionally substituted by one or two C1-6 alkyl groups which may be the same or different, a group COOR9, wherein R9 is a hydrogen atom, or a C1-6 alkyl group, and a group of formula (II), wherein R1 independently is as defined for formula (II) and R2 is a hydrogen atom; with the proviso that not more than two of R3, R4, R5, R6, and R7 may be a group of formula (II) and/or a group COOR9.