Separately Packed Curable Composition for Dental Adhesion
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Solution Overview
Problem
Dental curable compositions face challenges with low storage stability, delayed curing times, and variations in polymerization activity when stored at room temperature or higher, particularly due to the thermal instability of benzoyl peroxide and the reactivity of peroxides in acidic environments, which affect adhesion strength and pot life.
Innovation Solution
A separately packed curable composition comprising a first pack with a transition metal compound and a second pack containing an aromatic amine compound, sulfinic acid, and a peroxyester or alkyl peroxide, where the transition metal compound is selected from vanadium compounds, ensuring stable polymerization activity and adhesion strength even after long-term storage at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If benzoyl peroxide is used as an oxidizing agent in the first pack, then polymerization activity is sufficient, but storage stability deteriorates and refrigeration is required
Solution Approach 1:
The patent changes the chemical parameter of the oxidizing agent from benzoyl peroxide to a more thermally stable peroxide compound, which fundamentally alters the storage stability characteristics while maintaining polymerization effectiveness
Solution Approach 2:
The patent accepts that the oxidizing agent has limited shelf life at room temperature and designs the system accordingly, allowing the composition to be stored without refrigeration for a practical period before use
2Duration of action of moving object
If the amount of benzoyl peroxide is reduced to extend pot life, then storage stability improves, but polymerization properties deteriorate
Solution Approach 1:
The patent changes the type of peroxide compound used, selecting varieties with different decomposition characteristics that provide both extended pot life and maintained polymerization effectiveness
Solution Approach 2:
The patent uses combinations of different peroxide compounds (e.g., t-butyl peroxide, cumene hydroperoxide) to achieve synergistic effects that extend pot life while ensuring sufficient polymerization activity
3Reliability
If a polymerizable monomer is increased in amount to ensure long-term storage stability, then storage stability improves, but curing may occur during storage at high temperature
Solution Approach 1:
The patent divides the curable composition into separately packed first and second packs, keeping the oxidizing agent and reducing agent apart until use, which prevents premature polymerization while maintaining storage stability
Solution Approach 2:
The patent introduces a coordinating agent as an intermediary that controls the interaction between peroxide and polymerizable monomer, preventing premature curing while ensuring proper polymerization when activated
4Adaptability or versatility
If a redox polymerization initiator is used to achieve curing in deep tooth parts, then adaptability improves, but the number of packs increases to three or more
Solution Approach 1:
The patent combines the oxidizing agent and reducing agent into just two separately packed components that are mixed before use, simplifying the system while maintaining redox polymerization capability for deep tooth applications
Solution Approach 2:
The patent designs a dual-cure system where the same two-pack composition can be activated by either chemical redox reaction or photopolymerization, making it universally applicable to both deep and shallow restorations
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 maintains a sufficient pot life with minimal delay in curing time and preserves polymerization activity, providing excellent adhesion strength and storage stability, making it suitable for various dental applications.
Implementation Method 1
When the first pack including the oxidizing agent and the second pack including the reducing agent are mixed, a redox reaction occurs to generate radicals, which react with a polymerizable monomer to initiate a polymerization reaction
Implementation Method 2
a curable composition including a polymerizable monomer capable of radical polymerization and a radical polymerization initiator is widely used
Data Source
AI summary
Provided is a curable composition that has a sufficient pot life and does not cause a significant delay in curing time even after long-term storage at room temperature or higher. A separately packed curable composition includes: (A) a first pack containing: (a1) a polymerizable monomer having no acidic group, (b) a polymerizable monomer having an acidic group, and (c) a transition metal compound; and (B) a second pack containing: (a2) a polymerizable monomer having no acidic group, (d) an aromatic amine compound, and (e) at least one compound selected from sulfinic acid and a salt thereof.