Lithium Silicate Diopside Glass Ceramic Machinability
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Solution Overview
Problem
Existing dental glass ceramics lack adjustable translucence and sufficient mechanical strength for aesthetically demanding restorations, and are difficult to machine after crystal phase formation.
Innovation Solution
A lithium silicate-diopside glass ceramic with a composition of 53.0 to 75.0 wt.-% SiO2, 10.0 to 23.0 wt.-% Li2O, and 1.0 to 13.0 wt.-% CaO, which allows for controlled crystallization of lithium silicate and diopside phases, enabling adjustable translucence and improved mechanical properties, and can be easily processed using CAD/CAM techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If glass ceramics are heat treated to form lithium disilicate phase for high strength, then mechanical strength is improved, but machining becomes time-consuming and associated with high tool wear
Solution Approach 1:
The patent changes the crystal phase composition from lithium disilicate to lithium silicate-diopside system, fundamentally altering the material parameters to achieve both high strength and improved machinability. The specific compositional ranges (53-75 wt% SiO2, 10-23 wt% Li2O, 1-13 wt% CaO) create a unique phase structure that maintains mechanical properties while reducing tool wear during CAD/CAM processing
2Strength
If multiple crystal phases are present in glass ceramics, then mechanical strength is improved, but translucence decreases due to high opacity
Solution Approach 1:
The patent applies local quality by creating a specific two-phase structure where lithium silicate and diopside coexist in controlled proportions and distributions. This localized phase arrangement allows different regions to contribute differently to overall properties: lithium silicate provides strength while diopside control opacity, achieving a balance between mechanical strength and translucence that single-phase or multi-phase systems cannot achieve
3Strength
If glass ceramics contain diopside as crystal phase, then mechanical properties are improved, but translucence cannot be adjusted over a broad range
Solution Approach 1:
The patent introduces dynamics by enabling continuous adjustment of translucence through compositional variations within the lithium silicate-diopside system. By varying the ratios of lithium oxide (10-23 wt%), calcium oxide (1-13 wt%), and silicon dioxide (53-75 wt%), the material's optical properties can be dynamically tuned for different dental restoration applications while maintaining diopside's mechanical benefits
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 glass ceramic achieves a desirable combination of optical and mechanical properties, allowing for precise shaping and high strength, making it suitable for various dental restorations while maintaining chemical resistance and ease of machining.
Implementation Method 1
allows for controlled crystallization of lithium silicate and diopside phases
Data Source
AI summary
Lithium silicate-diopside glass ceramics are described which are characterized by a controllable translucence and can be satisfactorily processed mechanically and therefore can be used in particular as restoration material in dentistry.