Denture Base Material Using Aliphatic Urethane Acrylates
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Solution Overview
Problem
Current cold-curing denture base materials lack sufficient fracture resistance and tend to yellow due to the use of elasticizing synthetic rubber molecules, which are unsuitable for auto- or cold-polymerizing compositions and are prone to chipping when subjected to impact, leading to additional costs and work for dental laboratories.
Innovation Solution
A cold-curing denture base material composed of a liquid monomer component, a powdery component containing bead polymers, and an initiator for auto- or cold polymerization, where aliphatic urethane acrylates and methacrylates are used, specifically aliphatic urethane diacrylate resin, to enhance fracture toughness and color stability, eliminating the need for elasticizing synthetic rubber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If elasticizing synthetic rubber molecules (such as butadiene copolymers or butadiene-acrylonitrile copolymers) are added to achieve high fracture resistance, then fracture toughness is improved, but yellowing occurs due to nitrile groups reacting with oxidizing substances
Solution Approach 1:
The patent changes the chemical composition parameters by replacing synthetic rubber molecules containing nitrile groups with aliphatic urethane (meth)acrylate oligomers that have equivalent elasticizing properties but do not contain yellowing-prone nitrile groups. This parameter substitution maintains fracture toughness while eliminating yellowing.
Solution Approach 2:
The patent uses aliphatic urethane (meth)acrylate oligomers as a temporary or alternative solution that provides the necessary elasticizing effect during the polymerization process and in the final product, without the long-term degradation issues of synthetic rubber. These oligomers serve their function without the harmful byproducts.
2Strength
If core-shell particles are used to achieve high fracture resistance, then fracture toughness is improved, but the short swelling time of autopolymerizing or cold-curing polymers is insufficient for adequate bead swelling
Solution Approach 1:
The patent extracts the essential functional property (elasticity) from the core-shell particle structure and achieves it through a different mechanism - using aliphatic urethane (meth)acrylate oligomers that provide elasticizing effects through their molecular structure and flexibility, bypassing the need for time-consuming swelling processes.
Solution Approach 2:
The patent replaces the mechanical swelling process required by core-shell particles with a chemical solution - the aliphatic urethane (meth)acrylate oligomers that inherently provide the necessary elasticity and fracture resistance through their molecular characteristics, eliminating the time-dependent mechanical swelling step.
3Strength
If heat-curing denture materials are used to achieve high fracture resistance, then fracture toughness is improved, but the processing complexity and curing time increase
Solution Approach 1:
The patent replaces the thermal curing mechanism with a chemical polymerization process using aliphatic urethane (meth)acrylate oligomers that can cure at lower temperatures or ambient conditions, maintaining high fracture toughness while simplifying the curing process and reducing equipment requirements.
Solution Approach 2:
The patent changes the curing temperature parameter and chemical composition to achieve fracture-resistant materials through autopolymerization or cold-curing mechanisms, eliminating the need for complex heat-curing equipment and processes while maintaining or improving mechanical properties.
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 fracture toughness greater than 1.8 MPa*m 1/2 and fracture work greater than 400 J/m 2, with minimal yellowing (less than one unit change in yellowness value) after storage in demineralized water, maintaining color stability and avoiding negative effects on Suntest results.
Implementation Method 1
Hardened denture materials tend to chip off thin, tapered areas when removed from the investment material. Furthermore, due to the limited motor skills of typically elderly denture wearers, dentures are sometimes dropped onto hard surfaces (tiles, sinks), which can also lead to chipping.
Implementation Method 2
EP 1923 037 A2 discloses a fracture-resistant denture material based on methyl methacrylate, to which liquid butadiene-(meth)acryl- or -(meth)acrylonitrile oligomers are added as modifiers. The material is obtained by autopolymerization or cold polymerization
Implementation Method 3
One problem is that many elasticizing synthetic rubber molecules contain nitrile groups which tend to yellow, typically in the presence of oxidizing substances such as peroxides or atmospheric oxygen.
Data Source
AI summary
A self-polymerizing or cold-polymerizing composition comprising (A) a liquid monomer component, (B) a powdered component, and (C) at least one initiator or initiator system for self-polymerization or cold polymerization, wherein (A) and/or (B) contain at least one member of the groups of aliphatic urethane acrylates and aliphatic urethane methacrylates, yields a fracture-resistant denture base material which, after curing, exhibits in particular a fracture toughness of > 1.8 MPa*m1/2 and a fracture energy of > 400 J/m2, and preferably also, after 8 weeks of storage in deionized water at 50°C, a difference in the yellow value, the b-value, of a maximum of one unit. Elasticizing synthetic rubber is preferably not present.