Dental Composition Particle Distribution for Grinding and Shrinkage
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Solution Overview
Problem
Conventional dental compositions exhibit high polymerization shrinkage, leading to poor adhesiveness, mechanical strength, and increased internal stress, which complicates the formation of accurate dental prostheses and increases the risk of secondary caries, especially when used to fill large cavities or manufactured into dental blocks.
Innovation Solution
A dental composition with a specific particle size distribution, comprising a first largest group of particles with sizes ranging from 0.7 to 1.5 times the representative particle size, and a second largest group, optimized to achieve a low rate of polymerization shrinkage, improved filling properties, and enhanced mechanical strength, allowing for better handling and preservation stability as a paste and reduced sink marks upon curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If dental composition with high rate of polymerization shrinkage is used, then filling property is improved, but adhesiveness and edge sealing deteriorate due to strain and gap at interface
Solution Approach 1:
The patent changes the particle size distribution parameters of the filler, specifically controlling the proportion of particles in the 0.7 to 1.5 times range of the representative particle size to be 0.8 or more. This parameter optimization reduces polymerization shrinkage rate while maintaining good filling property, thereby preventing interface strain and gap formation that would compromise adhesiveness and edge sealing.
2Ease of operation
If dental composition with high rate of polymerization shrinkage is used to fill large cavity, then filling property is improved, but mechanical strength deteriorates due to secondary caries
Solution Approach 1:
The patent optimizes the particle size distribution parameters, specifically setting the ratio of particles with size 0.7 to 1.5 times the representative particle size to 0.8 or more. This reduces polymerization shrinkage rate, preventing the formation of gaps and strain at the tooth-material interface that would lead to secondary caries and mechanical strength deterioration in large cavity restorations.
3Productivity
If dental composition with high rate of polymerization shrinkage is cured outside oral cavity, then production efficiency is improved, but mechanical strength deteriorates due to internal stress and cracks
Solution Approach 1:
The patent changes the filler particle size distribution parameters, specifically controlling the proportion of particles in the 0.7 to 1.5 times range of the representative particle size to be 0.8 or more. This reduces the polymerization shrinkage rate, thereby minimizing internal stress and crack formation during extraral curing, allowing high-strength dental blocks to be produced efficiently outside the oral cavity.
4Strength
If conventional large size quartz particles are used as filler, then mechanical strength is improved, but grinding sensation deteriorates
Solution Approach 1:
The patent changes the particle size distribution of the filler from conventional large size particles to a optimized distribution where particles with size 0.7 to 1.5 times the representative particle size constitute 0.8 or more of the total particle number. This creates a balanced structure that maintains adequate mechanical strength while providing smooth grinding sensation and surface finish comparable to natural teeth.
5Ease of operation
If ultrafine silica particles are used as filler, then grinding sensation is improved, but mechanical strength deteriorates due to high viscosity limiting filler amount
Solution Approach 1:
The patent optimizes the particle size distribution parameters, specifically setting the ratio of particles with size 0.7 to 1.5 times the representative particle size to 0.8 or more. This balanced distribution reduces material viscosity compared to ultrafine particle systems, allowing sufficient filler content to be incorporated while maintaining good grinding sensation and achieving adequate mechanical strength in the cured product.
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 optimized particle size distribution results in a dental composition with reduced shrinkage, improved mechanical strength, and enhanced handling properties, enabling the production of dental prostheses with smoother surfaces and reduced internal stress, suitable for both manual and automated grinding processes.
Implementation Method 1
The dental composition changes from paste to hardened product by curing the resin matrix comprised in the dental compositions
Data Source
AI summary
Provided is a dental composition comprising a first largest group of particles and resin matrix, wherein the first largest group consists of particles whose particle size ranges from 0.7 to 1.5 times the representative particle size of the first largest fraction in a population of particles included in the composition whose particle size ranges from 110 to 1000 μm; and wherein the ratio of the number of particles included in the first largest group to the number of particles whose particle size ranges from 0.5 to 2.0 times the representative particle size of the first largest fraction is equal to or more than 0.8.