Glass Ceramic Composition for Dental Applications
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Solution Overview
Problem
Existing glass ceramic materials for dental applications are prone to edge cracking during grinding due to uncontrolled lithium disilicate formation, leading to increased processing costs and reduced toughness, which is exacerbated by the need for high zirconia content that complicates melting and uniformity.
Innovation Solution
A glass ceramic material composition optimized with 58-72% SiO2, 0-4% Al2O3, 0-5% Na2O, 3-8% K2O, 8-17% Li2O, 2.5-5% P2O5, 0-2% MgO, 0-2.5% B2O3, and 0-3% ZrO2, with specific ratios and processing steps including high-temperature melting, water quenching, wet ball milling, dry-pressing, warm isostatic pressing, and crystallization heat treatment to achieve lithium metasilicate with >50% crystallinity and lithium disilicate with >80% crystallinity, allowing for efficient grinding without edge collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If lithium disilicate glass ceramic is used to improve strength, then mechanical strength is improved, but edge cracking during grinding occurs and bur service life decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the glass ceramic by controlling the content of network formers (SiO2, B2O3, P2O5) within specific ranges and adjusting the ratio of network modifiers (Li2O, Na2O, K2O) to network formers. This parameter optimization achieves a balance between strength and processability, allowing the material to maintain high strength while being grindable without edge cracking
Solution Approach 2:
The patent creates a composite glass ceramic system combining multiple oxides (SiO2, B2O3, P2O5, Li2O, Na2O, K2O, Al2O3) where each component contributes specific properties. The synergistic interaction between these components produces a material that simultaneously achieves high strength, controlled crystallization behavior, and improved grinding performance
2Strength
If zirconia content is increased to improve toughness, then fracture toughness is improved, but melting difficulty increases and product uniformity decreases
Solution Approach 1:
The patent optimizes the zirconia content parameter within a specific range (0.1-5 wt%) rather than using high concentrations. This controlled parameter adjustment achieves sufficient toughness improvement while avoiding the melting difficulties and uniformity problems associated with high zirconia content. The patent also adjusts the ratio of zirconia to other components to maintain meltability
3Ease of manufacture
If crystallization temperature is decreased to facilitate grinding, then processing ease is improved, but toughness decreases due to high glass phase proportion
Solution Approach 1:
The patent adjusts the crystallization temperature parameter to an optimal range (650-750°C) and controls the holding time (2-6 hours) to achieve partial crystallization with 30-70% crystal phase content. This parameter optimization allows the material to be sufficiently crystallized for easy grinding while maintaining enough glass phase (30-70%) to preserve toughness and prevent edge cracking
Solution Approach 2:
The patent applies partial crystallization rather than complete crystallization, maintaining a balanced proportion of crystalline and glass phases. This partial action approach ensures the material has enough crystal content for grindability while retaining sufficient glass phase for toughness, avoiding the extremes of either complete crystallization or complete amorphous state
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 solution enables glass ceramic materials with improved toughness and grinding performance, achieving hardness of 500-590 kgf/mm2 and flexural strength of >400 MPa, with reduced bur damage and edge collapse, offering a competitive advantage and enhanced application prospects.
Implementation Method 1
high-temperature melting the raw materials
Implementation Method 2
performing wet ball milling treatment after water quenching
Implementation Method 3
performing a warm isostatic pressing treatment to obtain a second green body
Implementation Method 4
subjecting the second green body to a crystallization heat treatment to obtain a glass ceramic material
Implementation Method 5
crystallization heat treatment
Data Source
AI summary
Disclosed are a glass ceramic material, a preparation method thereof, and a denture. The glass ceramic material includes the following components by mass percentage: 58% to 72% of SiO2, 0% to 4% of Al2O3, 0% to 5% of Na2O, 3% to 8% of K2O, 8% to 17% of Li2O, 2.5% to 5% of P2O5, 0% to 2% of MgO, 0% to 2.5% of B2O3, 0% to 5% of ZnO and 0% to 3% of ZrO2. In the present application, by optimizing the composition and ratio of the glass ceramic material, and combining with a matching process system, it is possible to control the formation of lithium disilicate while the crystallinity of lithium metasilicate glass ceramic can be improved without an introduction of a high ratio of zirconia content, thereby improving the grinding performance of the glass ceramic. The present application is applicable to the field of material technology.