Low Viscosity Dental Adhesive with Controlled Acidity
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Solution Overview
Problem
Current dental adhesive systems, particularly self-etch systems, face challenges in achieving adequate bond strength to enamel and compatibility with self-cured resin cements and composite resins, often resulting in inadequate adhesion and sensitivity issues due to acidic monomers and thick adhesive films.
Innovation Solution
A light-curable dental adhesive composition with a controlled acidity and low viscosity, combined with a primer, that forms a thin film, enhancing adhesion to both dentin and enamel without the need for additional activators, ensuring compatibility with self-cured resin cements and composite resins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If self-etch adhesive system is used to eliminate the need for separate acid etchant and reduce technique sensitivity, then ease of operation is improved, but bond strength to enamel deteriorates
Solution Approach 1:
The patent modifies the chemical parameters of the self-etch adhesive by incorporating specific acidic monomers (itaconic acid, methacrylic acid) at controlled concentrations (0.1-5% and 0.1-2% respectively), along with phosphoric acid (0.1-5%). This parameter optimization enables the adhesive to achieve adequate enamel etching capability while maintaining the simplified self-etch application process without requiring separate etching steps.
2Strength
If adhesive contains high concentration of acidic monomers to improve etching efficacy, then bond strength to enamel is improved, but compatibility with self-cured resin cement deteriorates
Solution Approach 1:
The patent carefully balances the concentration of acidic monomers within specific ranges (itaconic acid: 0.1-5%, methacrylic acid: 0.1-2%, phosphoric acid: 0.1-5%) to achieve adequate enamel etching while preventing excessive acidity that would interfere with the redox initiator system of self-cured resin cements. This parameter optimization resolves the contradiction between etching efficacy and cement compatibility.
Solution Approach 2:
The adhesive composition combines multiple acidic monomers (itaconic acid, methacrylic acid, phosphoric acid) with non-acidic monomers and additional functional components to create a composite material system. This composite approach allows the adhesive to provide sufficient etching capability through the synergistic action of multiple acids while the overall composition remains compatible with self-cured resin cements due to the balanced formulation.
3Strength
If adhesive has high viscosity to provide adequate film thickness for adhesion, then bond strength is improved, but interference with seating indirect restoration increases
Solution Approach 1:
The patent optimizes the viscosity parameter of the adhesive to fall within the range of 50-500 cP at 25°C. This viscosity control allows the adhesive to form an adequate film for bonding while remaining thin enough (controlled film thickness) to not interfere with the seating of indirect restorations. The specific viscosity range balances film-forming capability with clinical applicability.
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 solution achieves improved bond strength to both dentin and enamel, reduces tooth sensitivity, and ensures compatibility with self-cured resin cements and composite resins, resulting in a reliable and efficient restorative procedure.
Implementation Method 1
light-curable dental adhesive composition
Data Source
AI summary
A dental adhesive composition comprising (i) at least one non-acidic polymerizable monomer having at least one ethylenically unsaturated group, (ii) optionally one or more acidic compounds, (iii) at least one photoinitiator, (iv) at least one solvent, and (v) about 0-40% by weight of one or more fillers; wherein the weight ratio of non-acidic polymerizable monomers/acidic compounds in the adhesive composition is more than about 4.5; the viscosity of the adhesive composition is less than about 350 centipoise (cP) at 25°C; and the adhesive composition excluding solvent and filler has an acid number of less than about 0.75 mmol NaOH/g. The dental adhesive composition is used with a dental primer composition, which may be provided together in a kit.