Polymerizable Thiourea Redox Initiator for Dentin Bonding

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing initiator systems for curing polymerizable compositions containing acidic components, particularly resin modified glass ionomer cements, face challenges in achieving adequate bond strength to dentin and are not suitable for aqueous environments, while also requiring improved toxicological safety and compatibility with hydrophilic and hydrophobic components.

Innovation Solution

An initiator system comprising a hydroperoxide component, a transition metal component, and a polymerizable thiourea component with a (meth)acrylate moiety through a C3-11 alkyl chain, which functions as a reducing agent in a redox-initiator system, enhancing bond strength to dentin and maintaining compatibility in aqueous conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional initiator systems are used for curing polymerizable compositions containing acidic components, then the composition can be cured, but the bond strength to dentin is insufficient

Engineering Contradiction:

Improvebond strength to dentinVSAvoidcuring effectiveness

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The initiator system combines three different components (hydroperoxide, transition metal, and polymerizable thiourea) into a composite redox-initiator system. This composite approach allows the system to effectively cure polymerizable compositions containing acidic components while simultaneously achieving adequate bond strength to dentin, resolving the contradiction between curing effectiveness and bond strength.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical parameters of the initiator system by using a polymerizable thiourea component with specific structural features (C3-11 alkyl chain). This parameter change enables the initiator system to work effectively in aqueous environments and achieve both proper curing and improved bond strength to dentin.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If conventional initiator systems are used, then the composition can be cured, but the system is not suitable for aqueous environments

Engineering Contradiction:

Improvesuitability for aqueous environmentsVSAvoidcuring performance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the initiator components to make them suitable for aqueous environments. The hydroperoxide component, transition metal component, and polymerizable thiourea component are selected and formulated to maintain stability and reactivity in the presence of water, allowing the system to cure RMGICs effectively in aqueous conditions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The polymerizable thiourea component acts as an intermediary that bridges the hydroperoxide and transition metal components in the redox reaction. This intermediary enables the initiator system to function properly in aqueous environments by mediating the electron transfer process while remaining stable in water.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If existing initiator systems are used, then the composition can be cured, but toxicological safety requires improvement

Engineering Contradiction:

Improvetoxicological safetyVSAvoidcuring effectiveness

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent uses a polymerizable thiourea component that is designed to be consumed during the polymerization reaction. The thiourea component reacts with the hydroperoxide and transition metal to initiate polymerization, and its derivatives are incorporated into the polymer matrix, reducing the amount of free toxic substances remaining in the final product.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent converts the potential harmful effect of thiourea derivatives by making them polymerizable. The thiourea component and its reaction products become part of the polymerized matrix, transforming from potentially toxic free substances into integrated structural elements of the cured material, thereby improving toxicological safety while maintaining curing effectiveness.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 initiator system effectively cures resin modified glass ionomer cements, improving bond strength to dentin and ensuring compatibility with both hydrophilic and hydrophobic components, while maintaining suitable curing conditions and safety.

Implementation Method 1

a polymerizable thiourea component which functions as a reducing agent in a redox-initiator system

Methodology Applied

Scientific EffectRedox reactions: Redox Reactions

Data Source

PatentEP4329704B1Initiator system with polymerizable thiourea component, dental composition and use thereof

Publication Date: 2025.10.08 SOLVENTUM INTELLECTUAL PROPERTIES CO

AI summary

The invention relates to an initiator system for curing a dental composition, the initiator system comprising a hydroperoxide component, a transition metal component, a polymerizable thiourea component, the polymerizable thiourea component comprising a thiourea moiety which is attached to a (meth)acrylate moiety through a C3-11 alkyl chain. The invention also relates to a dental composition comprising such an initiator system, and curable components, in particular curable components comprising acidic moieties.