Lithium Silicate Glass Ingot for Dental Restorations
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Solution Overview
Problem
Lithium disilicate glass ceramics used in dental restorations have low initial strength, making them prone to flaking and disruptions during CAD/CAM processing, requiring a two-stage crystallization process that is time-consuming and costly, and lacks sufficient translucence and chemical resistance.
Innovation Solution
Developing glass compositions in the SiO2—Li2O—ZrO2 system with lithium metasilicate as the main crystal phase, allowing direct machining with CAD/CAM systems without flaking, achieving high strength, and ensuring good contour accuracy and chemical stability through partial crystallization at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lithium disilicate glass ceramic is used for dental restorations, then the material can be processed by CAD/CAM systems, but the initial strength is low causing flaking and disruptions during processing
Solution Approach 1:
The patent applies preliminary crystallization to the glass ceramic material before CAD/CAM processing. By performing a first crystallization step that forms lithium metasilicate crystals in advance, the material gains sufficient strength to withstand subsequent machining operations without flaking or disruptions, while still maintaining CAD/CAM processability.
2Strength
If a two-stage crystallization process is used to improve strength, then the final strength increases, but the production time and costs increase
Solution Approach 1:
The patent extracts and eliminates the need for the second crystallization step from the traditional two-stage process. By designing a glass composition that achieves sufficient strength and stability after a single crystallization treatment, the production process is simplified, reducing both time and cost while maintaining the necessary mechanical properties for dental restorations.
3Ease of operation
If traditional glass ceramic composition is used, then the material can be machined, but flaking and disruptions occur during CAD/CAM processing
Solution Approach 1:
The patent changes the chemical composition parameters of the glass ceramic by incorporating specific amounts of Al2O3 (1-10 wt%), TiO2 (0.5-5 wt%), and other oxides in controlled proportions. These compositional modifications alter the material's structural properties and crystallization behavior, enabling it to maintain structural integrity and resist flaking during CAD/CAM machining operations.
4Productivity
If the final crystallization is effected quickly, then production time is reduced, but the contour accuracy cannot be achieved
Solution Approach 1:
The patent performs preliminary crystallization with controlled heating and holding parameters before the final shaping operations. This pre-crystallization step establishes a stable microstructure that allows subsequent rapid crystallization or finishing operations to proceed quickly while maintaining high contour accuracy, as the material has already developed adequate structural framework.
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 method reduces production time and costs by eliminating the need for oven-based heat treatment, enabling direct pressing or casting of dental restorations with improved strength, translucence, and chemical resistance, while maintaining material properties.
Implementation Method 1
at least a partial crystallisation occurs due to increased temperatures
Implementation Method 2
due to increased temperatures
Data Source
AI summary
The invention refers to a method for producing a dental restoration comprising a lithium silicate glass or glass ceramic as well as a dental restoration inself. The invention further refers to a ingot with the same composition having a defined strength.