Dual-Curing Dental Composition Reducing Polymerization Heat and Shrinkage

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Solution Overview

Problem

Current dental composite materials face challenges with excessive heat generation and shrinkage during polymerization, leading to potential tissue damage and inaccuracies in fit, while existing solutions have not effectively addressed these issues through chemical formulation.

Innovation Solution

A dual-curing, multi-component dental composition incorporating photopolymerizable monomers, molecular weight regulators like α-terpinene, and inorganic fillers, which allows for controlled polymerization with reduced heat release and shrinkage, ensuring rapid hardening and optimal fit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional dental composite materials are used for temporary restorations, then the material provides basic protective function, but excessive heat is generated during polymerization causing potential pulp damage

Engineering Contradiction:
Improveheat development during polymerizationVSAvoidthermal damage to pulp
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical parameters of the polymerization system by introducing a redox initiator system (benzoyl peroxide and dimethyl-p-toluidine) that enables low-temperature chemical curing. This alternative initiation mechanism operates at lower temperatures compared to conventional thermal or photoinitiated polymerization, thereby reducing the heat developed during curing and preventing thermal damage to the dental pulp.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the potentially harmful exothermic polymerization reaction into a beneficial low-temperature chemical curing process. By using the redox reaction between benzoyl peroxide and dimethyl-p-toluidine, the polymerization proceeds at controlled lower temperatures, transforming the harmful thermal effect into a beneficial gentle curing mechanism that protects dental tissues.

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

2Manufacturing precision

If conventional dental composite materials are used, then the material provides structural support, but shrinkage during polymerization leads to inaccuracies in fit and edge tightness

Engineering Contradiction:
Improvefit accuracy and edge tightnessVSAvoidshrinkage during polymerization
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent changes the compositional parameters by incorporating specific inorganic fillers (glass powder, barium sulfate) and molecular weight regulators (α-terpinene, γ-terpinene) that modify the polymerization shrinkage characteristics. These additives control the polymerization kinetics and reduce the overall shrinkage, improving fit accuracy and edge tightness while maintaining structural support.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite material system combining organic matrix (UDMA, TEGDMA), inorganic fillers (glass powder, barium sulfate), and molecular weight regulators (terpinenes). This composite formulation balances structural support from fillers with reduced shrinkage from the optimized organic matrix and regulators, achieving both mechanical strength and dimensional stability.

Inventive Principle:
Principle #40Composite materials

3Object-affected harmful factors

If conventional dental composite materials are used, then the material provides adequate mechanical properties, but residual monomers are released into the oral cavity causing potential allergic reactions

Engineering Contradiction:
Improverelease of allergenic monomersVSAvoidmechanical properties of restoration
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent changes the molecular parameters by incorporating molecular weight regulators (α-terpinene, γ-terpinene) that control the polymerization process to achieve higher conversion rates and lower residual monomer content. The regulators modify the polymer chain growth, resulting in a more complete polymerization that reduces free monomers while maintaining adequate mechanical properties through the composite filler system.

Inventive Principle:
Principle #35Parameter changes

4Shape

If light-curable composite materials are used, then the material cures rapidly with light activation, but the surface remains rough and difficult to polish to high gloss

Engineering Contradiction:
Improvesurface smoothness and polishabilityVSAvoidcuring speed
Core Design Contradiction:
ShapeVSProductivity

Solution Approach 1:

The patent uses a composite material formulation with inorganic fillers (glass powder, barium sulfate) that provide a smooth surface structure amenable to polishing. The combination of UDMA and TEGDMA with molecular weight regulators creates a matrix that cures rapidly under light while maintaining surface quality, allowing high-gloss polishability without sacrificing curing speed.

Inventive Principle:
Principle #40Composite materials

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 composition achieves low heat development and minimal shrinkage, providing a stable and accurate fit without residual monomers, ensuring patient safety and dental material integrity.

Implementation Method 1

The curing of light-curable dental composite materials occurs through photoinitiated polymerization. Here, after photochemical activation of an initiator system, chain reactions are initiated, with the liquid monomers being converted into a solid polymer via three-dimensional crosslinking.

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

one or more molecular weight regulators selected from the group consisting of compounds which can be reacted with a radical of a monomer of component (a), the reaction being carried out with abstraction of an H radical

Methodology Applied
Scientific EffectHydrogen abstraction:

Data Source

PatentEP2374445B1Dual hardening multi-component dental composition
Publication Date: 2015.07.29 VOCO GMBH
  • EP2374445B1 patent drawingFigure 1~2

AI summary

The invention primarily relates to a dual-curing, multi-component dental composition comprising: (a) one or more photopolymerizable monomers selected from the group consisting of acrylates and methacrylates, preferably from the group consisting of methacrylates; (b) one or more photoinitiators selected from the group consisting of alpha-diketones, benzoinalkyl ethers, thioxanthones, benzophenones, acylphosphine oxides, acetophenones, ketals, titanocenes, borates, and sensitizing dyes; (c) one or more molecular weight regulators selected from the group consisting of compounds that are reactive with a radical of a monomer of component (a), wherein the reaction takes place by abstraction of an H radical from the molecular weight regulator to the allyl position; (d) one or more polymerization inhibitors to increase the storage stability of the composition, preferably selected from the group consisting of hydroquinone monomethyl ether (HQME), phenols,(e) preferably 2,6-di-tert-butyl-4-methylphenol (BHT) and tert-butylhydroxyanisole (BHA), 2,2-diphenyl-1-picrylhydrazyl radicals, galvinoxyl radicals, triphenylmethyl radicals, 2,3,6,6-tetramethylpiperidinyl-1-oxyl radical (TEMPO) and its derivatives, and phenothiazine and its derivatives, (e) one or more inorganic fillers, (f) one or more initiators for chemical curing at ambient temperature, preferably a redox initiator system, and optionally one or more further additives. The invention further relates to a corresponding process for producing such a composition and the use of certain molecular weight regulators for producing a dual-curing, multi-component dental composition.