Dental Pattern Resin Composite Shrinkage Control
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Solution Overview
Problem
Conventional dental pattern resin composites deform or are difficult to remove due to large shrinkage during curing and expansion when heated, causing damage to the investment material.
Innovation Solution
A composite comprising a liquid formulation with monofunctional and polyfunctional (meth)acrylates, a polymerization accelerator, and a powder formulation with a (meth)acrylate copolymer and flowability-improving agent, optimized to suppress shrinkage and expansion, maintaining usability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a chemically polymerizable resin is used as a dental pattern material, then the material can be easily handled and used, but it deforms and becomes difficult to remove from the model due to large shrinkage during curing
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating (meth)acrylate copolymer particles (5-98 mass%) and controlling the ratio of monofunctional to polyfunctional (meth)acrylates (90:10 to 70:30 mass%). This parameter optimization reduces polymerization shrinkage while maintaining usability. The specific particle size range (40-130 μm) and flowability-improving agent content (0.1-20 mass%) are also carefully controlled to achieve the desired balance between handling properties and shrinkage reduction.
Solution Approach 2:
The patent creates a composite material system combining liquid (meth)acrylate monomers with solid (meth)acrylate copolymer particles and flowability-improving agents. This composite structure allows the material to exhibit both the ease of operation of liquid resins and the shrinkage resistance of polymer-filled systems. The multi-component formulation enables simultaneous achievement of usability and reduced deformation.
2Ease of manufacture
If a conventional composite for dental pattern resin is used, then the material can be molded, but it hugely expands when heated for burning, causing destruction or cracking of the investment material
Solution Approach 1:
The patent modifies the thermal properties by selecting specific (meth)acrylate copolymers with appropriate glass transition temperatures and controlling the copolymer composition (ethyl (meth)acrylate 20-90 mass%, methyl (meth)acrylate 10-80 mass%). These parameter changes result in reduced thermal expansion coefficients, preventing investment material damage during the burning-out process while preserving moldability.
Solution Approach 2:
The patent applies local quality by using a multi-component system where each component serves a specific function: monofunctional (meth)acrylates provide ease of molding, polyfunctional (meth)acrylates control crosslinking density, and (meth)acrylate copolymer particles provide thermal stability. This localized functional distribution allows the material to exhibit low expansion when heated while maintaining good moldability during application.
3Manufacturing precision
If the content of polyfunctional (meth)acrylate is increased to reduce shrinkage, then curing shrinkage decreases, but the material becomes too rigid and loses usability
Solution Approach 1:
The patent optimizes the polyfunctional (meth)acrylate content parameter within the specific range of 10-30 mass% of the total liquid formulation. This parameter control ensures sufficient crosslinking to reduce shrinkage while preventing excessive rigidity. The balanced composition (monofunctional 70-90 mass%, polyfunctional 10-30 mass%) achieves the optimal trade-off between shrinkage control and operational flexibility.
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 composite effectively reduces shrinkage and expansion during curing and heating, ensuring high usability and accuracy in dental precision casting.
Implementation Method 1
a liquid formulation and a powder formulation, wherein the liquid formulation comprises a polymerizable monofunctional (meth)acrylate, a polymerizable polyfunctional (meth)acrylate, and a polymerization accelerator
Data Source
AI summary
To provide a composite for a dental pattern resin whose shrinkage when curing and expansion when heated can be both suppressed as its usability is kept, the composite for a dental pattern resin includes a liquid formulation and a powder formulation, wherein the liquid formulation includes a polymerizable monofunctional (meth)acrylate, a polymerizable polyfunctional (meth)acrylate, and a polymerization accelerator, and the powder formulation includes more than 5 mass % of a (meth)acrylate copolymer on the basis of the total powder formulation.