Dental Composite Mill Blanks for Indirect Dentures
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Solution Overview
Problem
Current dental composites with high inorganic filler content face limitations in wear resistance, polymerization shrinkage, and mechanical properties, particularly in larger blocks, leading to potential cracking and porosity issues during curing.
Innovation Solution
A thermally polymerizable dental composite material comprising 60-85% inorganic filler, 10-40% urethane (meth)acrylate monomers, and a thermal initiator system, which allows for high flexural strength and low shrinkage, preventing cracking and porosity in large blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high inorganic filler content (60-85% by weight) is used to improve mechanical properties and reduce polymerization shrinkage, then wear resistance and strength are improved, but the material becomes more difficult to process and may develop cracks or pores during curing
Solution Approach 1:
The patent applies parameter changes by carefully controlling the filler content within 60-85% by weight, using specific particle size distributions (D10, D50, D90 values), and adjusting the monomer composition ratios to achieve optimal mechanical properties while preventing crack and pore formation during curing
Solution Approach 2:
The patent uses composite materials by combining inorganic filler particles with organic monomer matrices, creating a hybrid structure that leverages the strength and wear resistance of inorganic materials while maintaining the processability and flexibility of organic materials through carefully selected monomer compositions
2Adaptability or versatility
If large volume blocks are produced for indirect dentures, then versatility and application range are improved, but polymerization shrinkage increases leading to internal stresses and potential cracking
Solution Approach 1:
The patent applies parameter changes by using low-shrinkage monomers with specific molecular structures, controlling the degree of conversion through initiator system selection, and adjusting curing parameters to minimize polymerization shrinkage and associated internal stresses in large volume blocks
Solution Approach 2:
The patent applies preliminary action by pre-polymerizing the monomer mixture to form pre-polymerized filler particles or by using monomers with pre-established molecular structures that minimize shrinkage upon final curing, thereby reducing internal stresses before the final setting occurs
3Stability of the object's composition
If thermal polymerization is used for large blocks instead of light polymerization, then uniform curing throughout the volume is improved, but processing time and energy consumption increase
Solution Approach 1:
The patent applies continuity of useful action by using thermal polymerization that progresses uniformly throughout the entire material volume without interruption, ensuring continuous and homogeneous curing from the center to the surfaces of large blocks, unlike light polymerization which is limited by light penetration depth
4Stability of the object's composition
If homogeneous monochrome coloring is achieved in large blocks, then aesthetic quality is improved, but pigment dispersion and color uniformity become more difficult to control
Solution Approach 1:
The patent applies parameter changes by optimizing pigment concentration levels, particle size distributions, and dispersion methods to achieve homogeneous monochrome coloring in large blocks while maintaining ease of manufacturing through controlled mixing 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 composite material achieves flexural strength greater than 190 MPa and an elastic modulus of 12-21 GPa, ensuring robustness and minimizing shrinkage-related issues, even in large volumes, with homogeneous coloring and reduced risk of air bubbles during polymerization.
Implementation Method 1
a thermally initiatable peroxide... polymerization is performed at elevated temperature, preferably being in the range of about 90 to 150° C.
Implementation Method 2
to reduce the polymerization shrinkage that occurs during curing... the low shrinkage force and high flexural strength
Data Source
AI summary
A polymerisable dental composite material comprising(i) 70 to 85% by weight of an inorganic filler component comprising at least one dental glass and optionally at least one amorphous metal oxide,(ii) 10 to 30% by weight of at least one monomer comprising 1,3-bis(5′-alkyl-3′,8′-dioxo-2′-aza-4′,7′-dioxa-decyl-9′-en)phenyl and/or 1,3-bis(5′,9′-dialkyl-3′,8′-dioxo-2′-aza-4′,7′-dioxa-decyl-9′-en)phenyl,(iii) 0.01 to 5% by weight of at least one di-, tri-, tetra- or multi-functional monomer not being a urethane (meth)acrylate,(iv) 0.01 to 10% by weight of at least one initiator, of an initiator system and optionally of at least one stabilizer and optionally of at least one pigment, wherein the total composition of the composite material amounts to 100% by weight, and a polymerized composite material having a flexural strength of greater than or equal to 190 MPa and an elastic modulus of 12 to 21 GPa for the production of indirect dentures.