Self-Etching Dental Primer Composition for Single-Step Bonding
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Solution Overview
Problem
Current dental adhesive systems, particularly all-in-one adhesives, face challenges in achieving sufficient polymerization and adhesion between dental materials and tooth substance due to protonation of amine co-initiators by phosphoric acid groups, leading to reduced adhesion and prolonged treatment times.
Innovation Solution
A self-etching and self-undercoating primer composition comprising polymerizable (meth)acrylate or (meth)acrylamide monomers with acidic and hydrophilic groups, along with polyfunctionality, and the absence of photoinitiators and vanadium compounds, utilizing diffusion-based polymerization initiation and catalysts like copper and iron compounds to enhance adhesion and accelerate curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If phosphoric acid groups are used in all-in-one adhesives to etch tooth substance, then adhesion to dentin and enamel is improved, but amine co-initiators are protonated leading to reduced polymerization and adhesion
Solution Approach 1:
The patent extracts the problematic amine co-initiator from the system by using a redox-initiated polymerization mechanism that relies on persulfate decomposers instead. This eliminates the protonation issue while maintaining adhesion functionality through the acidic monomer groups.
Solution Approach 2:
The patent changes the polymerization initiation mechanism from amine-based chemical initiation to redox-based initiation using persulfate and its decomposers. This parameter change in the initiation pathway avoids the harmful protonation effect while enabling complete polymerization.
2Strength
If multiple curing steps are used to ensure complete polymerization and adhesion, then bond strength is improved, but treatment time is prolonged
Solution Approach 1:
The patent merges the etching, priming, and bonding functions into a single all-in-one adhesive composition that applies all necessary components simultaneously. The redox-initiated polymerization ensures complete curing in one step without requiring multiple separate application and curing cycles.
Solution Approach 2:
The adhesive composition is pre-formulated with all necessary components (acidic monomer, hydrophilic monomer, persulfate, and decomposer) in optimal concentrations. This preliminary preparation enables the dentist to apply a single layer that performs etching, priming, and bonding functions simultaneously, eliminating the need for multiple sequential steps.
3Reliability
If conventional adhesive systems are used to ensure proper adhesion, then bonding reliability is improved, but the risk of early curing is increased
Solution Approach 1:
The patent introduces a persulfate decomposer as an intermediary substance that controls the timing of polymerization. The decomposer prevents premature activation of the persulfate initiator during application, allowing the adhesive to be applied and positioned without early curing, then enables controlled polymerization when the decomposer is introduced or activated.
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 high adhesion values (>10 MPa) even after aging, simplifying the dental treatment process by allowing single-step application and curing of dental materials without early curing risks.
Implementation Method 1
utilizing diffusion-based polymerization initiation
Implementation Method 2
catalysts like copper and iron compounds to enhance adhesion and accelerate curing
Implementation Method 3
comprising a polymerizable (meth)acrylate or (meth)acrylamide monomer (i) of at least one acidic group such as for example a phosphoric acid group
Implementation Method 4
with (ii) at least one hydrophilic group such as for example a terminal hydroxy group
Data Source
AI summary
The invention relates to an aqueous dental single-component primer composition as well as a kit with this primer composition and a composite. The primer composition according to the present invention is self-etching and self-undercoating. It comprises a polymerizable (meth)acrylate or (meth)acrylamide monomer with (i) at least one acidic group such as for example a phosphoric acid group and with (ii) at least one hydrophilic group such as for example a terminal hydroxy group or two polymerizable (meth)acrylate or (meth)acrylamide monomers, wherein one thereof comprises (i) at least one acidic group and one thereof comprises (ii) at least one hydrophilic group. In addition, at least one of the polymerizable (meth)acrylate or methylacrylamide monomers comprises (i) a polyfunctionality, preferably an at least threefold polyfunctionality, particularly preferably a 3-, 4-, 5-, 6-, 7-, 8-, 9- or 10-fold polyfunctionality and/or (ii), or a further polymerizable (meth)acrylate or methylacrylamide monomer (iii) with a polyfunctionality, preferably an at least three-fold polyfunctionality, particularly preferably a 3-, 4-, 5-, 6-, 7-, 8-, 9- or 10-fold polyfunctionality is contained. This polyfunctionality inheres in the capability to polymerize. In particularly, at least three, preferably terminal, (meth)acrylate, (meth)acrylamide and/or allyl groups are present. Furthermore, this primer composition is characterized by the absence of a photoinitiator, a polymerization catalyst, in particularly a polymerization catalyst on the basis of vanadium as well as by the absence of an organic solvent.