Dual-Cure Dental Cement Composition for Semi-Cured Excess Removal
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Solution Overview
Problem
Existing dual cure dental cements face challenges in achieving a semi-cured state for easy removal of excess cement with reduced light irradiation, and they have insufficient adhesive strength, leading to potential detachment of restorations.
Innovation Solution
A dual cure dental cement composition that includes specific amounts of a polymerizable monomer, filler, chemical polymerization initiator, and photopolymerization initiator, excluding tertiary aromatic amines, with a balanced ratio of thiourea compound and α-diketone, allowing for a wide range of light irradiation conditions and enhanced cured body strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If existing dual cure dental cement is used with conventional light irradiation methods, then the excess cement can be removed in a semi-cured state, but the light irradiation time and intensity must be precisely controlled and the procedure is time-consuming
Solution Approach 1:
The patent changes the chemical parameters of the cement composition by incorporating specific accelerators (tertiary aromatic amines with specific structures, phosphine oxides, or sulfur compounds) to modify the polymerization kinetics. This allows the cement to reach a removable semi-cured state faster under light irradiation, reducing the time required for excess cement removal while maintaining ease of operation.
Solution Approach 2:
The patent applies light irradiation to the excess cement immediately after pressing the restoration into place, before the cement fully cures. This preliminary light exposure initiates surface polymerization, creating a semi-cured state that facilitates easy removal of excess cement while the underlying cement continues to cure chemically, thereby reducing overall treatment time.
2Ease of operation
If existing dual cure dental cement is used, then the cement can be cured chemically without light, but the adhesive strength is insufficient leading to potential detachment
Solution Approach 1:
The patent creates a composite curing system that combines chemical polymerization components (monomers, initiators, accelerators) with photopolymerization components. This composite material formulation ensures that the cement achieves adequate adhesive strength through chemical curing alone, while also being capable of enhanced surface curing with light for easier excess cement removal, thus resolving the strength deficiency.
Solution Approach 2:
The patent modifies the chemical composition parameters by adding specific accelerators (tertiary aromatic amines, phosphine oxides, or sulfur compounds) that enhance the chemical polymerization reaction efficiency and final cure strength. These parameter changes ensure sufficient adhesive bonding strength is achieved through chemical curing, eliminating the weakness of existing dual cure cements.
3Ease of operation
If more light irradiation is applied to achieve better semi-cured state, then excess cement removal is easier, but the risk of over-curing and loss of removability increases
Solution Approach 1:
The patent changes the chemical composition to include accelerators that create a more favorable polymerization rate curve under light exposure. This allows the cement to reach the optimal semi-cured state for removal within a shorter, more predictable time window, reducing the risk of over-curing while maintaining ease of excess cement removal, thereby improving reliability of the process.
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 cement achieves a favorable semi-cured state for easy excess cement removal with reduced light irradiation and maintains high adhesive strength, ensuring effective operability and durability of restorations.
Implementation Method 1
a composition that includes a polymerizable monomer (A), a filler (B), a chemical polymerization initiator (C), and a photopolymerization initiator (D)
Implementation Method 2
chemical polymerization initiator (C), and a photopolymerization initiator (D)
Data Source
AI summary
[Object] To provide dual cure cement with a wide range of a light irradiation amount that allows a favorable semi-cured state in which the excess cement can be easily removed to be maintained for several minutes, the cured body of the dual cure cement having a significantly higher strength than that of the existing dual cure cement. [Solving Means] Dental cement includes: a composition that includes a polymerizable monomer, a filler, a chemical polymerization initiator, and a photopolymerization initiator, the dental cement being characterized in that a specific tertiary aromatic amine that inhibits photopolymerization, such as N,N-di(1-hydroxyethyl)-p-toluidine, is not substantially included, the chemical polymerization initiator includes a thiourea compound having a specific structure, such as N-benzoylthiourea: 0.4 to 1.5 parts by mass, the photopolymerization initiator includes an α-diketone (d1): 0.3 to 0.8 parts by mass and a photopolymerization accelerator: 0.3 to 0.8 parts by mass, and a ratio of a content: x (parts by mass) of the (d1) to a content: y (parts by mass) of the (c2) is 0.3 to 1.9.