Dual-Paste Self-Adhesive Dental Composite for Dentin Bonding

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Solution Overview

Problem

Existing self-adhesive paste/paste-based dental materials for dentistry suffer from poor dentin adhesion properties, especially after storage, and are not as effective as powder/liquid systems, with most commercial systems showing dentin adhesion values of 0 to 2 MPa after curing.

Innovation Solution

A dual-curing multi-component dental material is developed, comprising a first paste with acid group-free radically polymerizable monomers and basic fillers, and a second paste with acid group-containing monomers and peroxides, where the pastes are mixed to create a self-adhesive, photo-curable composite that adheres well to tooth enamel and dentin without the need for additional solvents or complex mixing equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If paste/paste dosage form is used for self-adhesive dental material, then ease of operation and dosing flexibility are improved, but dentin adhesion properties deteriorate

Engineering Contradiction:
Improveease of operationVSAvoiddentin adhesion
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention divides the paste system into two separate pastes: Paste A containing basic fillers and acid group-free monomers, and Paste B containing acidic monomers and peroxide initiators. This segmentation prevents premature reaction while maintaining the ease of paste application, resolving the contradiction between ease of operation and adhesion reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The basic fillers in Paste A act as intermediaries that neutralize the acidic monomers from Paste B, controlling the reaction rate and preventing premature polymerization. This intermediary mechanism enables the paste system to maintain stability during handling while achieving reliable adhesion after mixing and application.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If powder/liquid system is used, then dentin adhesion properties are improved, but device complexity and ease of operation deteriorate

Engineering Contradiction:
Improvedentin adhesionVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the advantages of powder/liquid systems (reliable adhesion through acidic monomers) with the advantages of paste systems (ease of operation, no special equipment needed). By formulating both pastes with appropriate viscosity and combining them at the point of use, the invention achieves both high adhesion reliability and operational simplicity without requiring complex mixing devices.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If self-curing system is used, then adaptability to opaque restorations is improved, but storage stability deteriorates

Engineering Contradiction:
ImproveadaptabilityVSAvoidstorage stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The invention segments the curable components into two stable pastes that can be stored separately. Paste A contains basic fillers and acid group-free monomers, while Paste B contains acidic monomers and peroxide. This segmentation maintains storage stability while enabling self-curing functionality when the pastes are mixed and applied, allowing adaptability to opaque restorations without compromising storage stability.

Inventive Principle:
Principle #1Segmentation

4Reliability

If acidic monomers are added to achieve self-adhesion, then dentin adhesion is improved, but storage stability deteriorates

Engineering Contradiction:
Improvedentin adhesionVSAvoidstorage stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The basic fillers serve as intermediaries that neutralize the acidic monomers, preventing premature polymerization and maintaining storage stability. When the pastes are mixed and applied to the tooth surface, the acidic monomers are released to etch the dentin and create reliable adhesion. This intermediary mechanism resolves the contradiction between achieving self-adhesion and maintaining storage stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 material achieves significant improvements in dentin adhesion, with values of at least 4 MPa after self-hardening and up to 9.5 MPa after photohardening, maintaining stability even after storage, and allows for direct application to hard tooth structures without adhesion promoters.

Implementation Method 1

paste (A) contains (i) one or more acid group-free radically polymerizable monomers and (viii) photoinitiator

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Implementation Method 2

have an initiator system for self-curing at room temperature

Methodology Applied
Scientific EffectRadical polymerization:

Data Source

PatentEP2233123B2Self-adhesive multi-component dental material
Publication Date: 2020.03.11 IVOCLAR VIVADENT AG

AI summary

Curable multicomponent dental material comprises a first paste containing at least one acid group-free radically polymerizable monomers and filler; a second paste containing at least one acid group-containing radically polymerizable monomers and non-basic filler, where the multicomponent dental material in at least first paste or second paste contains at least one initiator for radical polymerization. Independent claims are included for following: (1) preparation of a ready-to-use dental material involving mixing first paste and second paste of the curable multicomponent dental material, in a volume ratio of 0.4:0.6 to 0.6:0.4; and (2) double syringe with a first and second reservoir comprising a curable multicomponent dental material, where first paste is contained in the first reservoir and second paste in the second reservoir.