Cs2O Lithium Silicate Glass Ceramic Multi-Layer Blocks
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Solution Overview
Problem
Current lithium silicate glass ceramic materials do not facilitate the production of multi-layered milling blocks with high translucency and uniform thermal expansion coefficients, leading to issues with layer adhesion and internal stress during heating.
Innovation Solution
Incorporating Cs2O into the lithium silicate glass ceramic composition, which adjusts the coefficient of thermal expansion (CTE) and refractive index, allowing for the production of multi-layered blocks with high translucency and reduced internal stress, while maintaining x-ray opacity and improved flowability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional lithium silicate glass ceramic materials are used, then the material can be produced, but the production of multi-layered milling blocks with high translucency is not facilitated and layer adhesion is poor
Solution Approach 1:
The patent modifies the chemical composition parameters of the lithium silicate glass ceramic by incorporating specific amounts of Cs2O (6-30 wt.%) along with controlled amounts of other oxides (Li2O: 7-16 wt.%, SiO2: 55-80 wt.%, Al2O3: 1-5 wt.%, P2O5: 1-5 wt.%). This parameter change in composition enables the material to achieve both high translucency and compatible thermal expansion properties, facilitating the production of multi-layered milling blocks with reliable layer adhesion.
2Illumination intensity
If lithium silicate materials with high translucency are used, then esthetic properties are improved, but internal stress and cracking occur during heating
Solution Approach 1:
The patent adjusts the chemical composition parameters to include Cs2O (6-30 wt.%) which modifies the thermal expansion characteristics of the glass ceramic. This parameter change enables the material to maintain high translucency while achieving compatible thermal expansion coefficients across different layers, thereby reducing internal stress and preventing cracking during heating processes.
Solution Approach 2:
The patent creates a homogeneous glass ceramic composition where Cs2O is uniformly distributed throughout the matrix along with other oxides (Li2O, SiO2, Al2O3, P2O5). This homogeneity ensures consistent thermal expansion behavior throughout the material, preventing localized stress concentrations that would lead to cracking while maintaining uniform translucency.
3Illumination intensity
If multi-layered blocks with different translucency are produced, then esthetic properties are improved, but consistent thermal expansion behavior is difficult to achieve
Solution Approach 1:
The patent modifies the base composition parameters to include Cs2O (6-30 wt.%) which provides a foundation for achieving compatible thermal expansion. This parameter change allows different layers with varying translucency (achieved through variations in other oxide contents) to maintain consistent thermal expansion behavior, as the Cs2O-containing base composition stabilizes the overall thermal properties.
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 use of Cs2O-containing lithium silicate materials enables the creation of multi-layered dental milling blocks with consistent thermal expansion behavior, reduced cracking, and enhanced esthetic properties, facilitating the production of complex shapes and stable dental restorations.
Implementation Method 1
Incorporating Cs2O into the lithium silicate glass ceramic composition, which adjusts the coefficient of thermal expansion (CTE)
Implementation Method 2
The lithium silicate glass ceramic can be transformed into a lithium disilicate glass ceramic upon application of a transformation step (e.g., application of a heating step)
Data Source
Figure 1~2
AI summary
The invention relates to a lithium silicate glass ceramic comprising CsO2 in an amount from about 6 to about 30 wt.-%. The invention also relates to a three-dimensional article comprising at least two layers (I) and (II), each layer (I) and (II) comprising a lithium silicate glass ceramic, the lithium silicate glass ceramics of layer (I) having a different translucency than the lithium silicate glass ceramic of layer (II).