Radiation-Curable Dental Resin Composition Balancing Strength and Transparency
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Solution Overview
Problem
Current dental materials for producing definitive prosthetic parts and orthopaedic appliances lack sufficient mechanical properties, such as bending fracture and fracture work, and are not suitable for radiation-curing rapid manufacturing or prototyping methods, with existing compositions failing to meet high aesthetic requirements due to transparency issues and limited compatibility with fillers.
Innovation Solution
A polymerisable, radiation-curable composition comprising acrylic acid esters with carboxy and anhydride groups, di-functional acrylates or methacrylates, and inorganic fillers like zirconium-doped silicon dioxide, which provides high transparency and enhanced mechanical properties, allowing for the production of dental prosthetic parts with improved flexural strength, E-modulus, and fracture work, while maintaining transparency and compatibility with additives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional acrylate compositions are used for radiation-curing methods, then the curing process can be completed, but the mechanical properties (bending fracture, fracture work) remain insufficient
Solution Approach 1:
The patent modifies the chemical composition parameters by incorporating specific acrylic acid esters with additional carboxy or anhydride groups, and di-functional acrylates/methacrylates with bivalent alicyclic groups. These compositional changes enable the cured material to achieve bending fracture values of at least 1.1 MPa m1/2 and fracture work of at least 250 J/m2, meeting dental restoration requirements while maintaining radiation-curability.
Solution Approach 2:
The invention creates a composite monomer system combining acrylic acid esters with carboxy/anhydride groups and di-functional acrylates/methacrylates with bivalent alicyclic groups. This composite composition synergistically improves mechanical properties (flexural strength ≥50 MPa, E-modulus ≥1500 MPa) while maintaining the ability to be cured by radiation, resolving the contradiction between curability and mechanical performance.
2Strength
If filler materials are added to improve mechanical properties, then strength increases, but transparency of the composition deteriorates
Solution Approach 1:
The patent selects inorganic fillers with specific physical parameters, particularly particle size (0.1-100 μm) and refractive index matching the polymer matrix. This parameter optimization allows the filled composition to maintain high transparency (≥95% at 1 mm thickness) while achieving flexural strength of at least 50 MPa, resolving the transparency-strength trade-off.
3Ease of manufacture
If conventional monomer mixtures are used, then the composition can be processed, but the fracture work and bending fracture values are too low for dental applications
Solution Approach 1:
The invention optimizes the monomer formulation with specific functional groups (carboxy, anhydride, bivalent alicyclic) and controlled molecular weights to achieve optimal balance between processability and mechanical performance. The resulting composition enables fracture work ≥250 J/m2 while maintaining appropriate viscosity and curing characteristics for dental manufacturing processes.
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 flexural strength of greater than 50 MPa, E-modulus of greater than 1500 MPa, and fracture work of greater than 250 J/m2, ensuring high-quality dental products with excellent transparency and mechanical performance, suitable for rapid prototyping and manufacturing methods.
Implementation Method 1
A polymerisable, radiation curable, in particular UV- Vis-, UV- or Vis-curable, composition comprising (i) monomers and (ii) at least one further component... (d) at least one photoinitiator for the UV and/or Vis spectral region
Data Source
AI summary
A polymerisable, radiation curable composition comprising (i) monomers comprising:(a) at least one acrylic acid ester having an additional carboxy group, acrylic acid ester having at least one additional anhydride group of carboxy groups, and/or derivative of the afore-mentioned acrylic acid esters,(b) at least one di-functional acrylate having a bivalent alicyclic group and/or at least one di-functional methacrylate having a bivalent alicyclic group, and(c) optionally, at least one disubstituted 4,4′-di(oxabenzene) dialkyl methane of formula I, and(ii) at least one further component comprising:(d) at least one photoinitiator for the UV and/or Vis spectral region or a photoinitiator system.The composition is suitable for producing dental prosthetic parts, orthopaedic appliances or dental pre-forms, having a) a flexural strength 50 MPa, b) an E-modulus ≥1500 MPa, c) a bending fracture ≥1.1 MPa m1/2, and/or d) a fracture work >250 J/m2 DIN EN ISO 20795-2.