Gradient Ceramic Dental Block for Natural Color Transition
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Solution Overview
Problem
Existing ceramic blocks for dental restorations face challenges in achieving a natural color profile with consistent optical properties, leading to aesthetically unsatisfactory results due to varying shrinkage and bond strengths across differently colored layers, which complicates the production process and final appearance.
Innovation Solution
A ceramic block with a transition area featuring a substantially constant variation gradient of optical properties, where the mixing ratio of ceramic compounds is tailored to minimize stress and enhance translucency, allowing for a more natural color transition and distribution of stress, while maintaining constant optical properties in specific areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If differently colored layers of ceramic compounds are combined to achieve a natural color profile, then the aesthetic appearance is improved, but the shrinkage and bond strength become inconsistent across layers
Solution Approach 1:
The patent applies parameter changes by continuously varying the mixing ratio of ceramic compounds (e.g., lithium disilicate and glass) along the vertical axis of the block. This creates a gradient structure where compositional parameters change systematically from bottom to top, enabling different optical properties in different regions while maintaining consistent sintering behavior through controlled composition transitions.
Solution Approach 2:
The patent implements local quality by assigning different ceramic compound compositions to different regions of the block. The bottom region contains a first composition optimized for structural support, while the top region contains a second composition optimized for aesthetics, with a transition zone providing gradual compositional change. This allows each region to have locally optimized properties without causing global inconsistencies.
2Illumination intensity
If multiple thin layers of ceramic compounds are presintered together to achieve color variation, then the color profile is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent merges multiple discrete layering operations into a single continuous gradient structure. Instead of presintering multiple separate layers and then assembling them, the invention creates a monolithic block with continuous compositional variation achieved through controlled mixing and single-step sintering, thereby simplifying the manufacturing process.
Solution Approach 2:
The patent uses composite materials by combining different ceramic compounds (such as lithium disilicate and glass) in varying proportions throughout the block. This composite approach allows tuning of both mechanical and optical properties through composition control, achieving natural tooth appearance while maintaining structural integrity.
3Illumination intensity
If the mixing ratio of ceramic compounds is changed to achieve natural color transition, then the aesthetic appearance is improved, but stress peaks occur due to varying shrinkage
Solution Approach 1:
The patent applies beforehand cushioning by introducing a transition zone with gradually changing composition between regions of different ceramic compounds. This gradient structure acts as a buffer that distributes and cushions the thermal and mechanical stresses that would otherwise concentrate at sharp interfaces, preventing stress peaks and potential cracking.
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 provides an aesthetically improved ceramic block with a natural appearance, reducing stress peaks and allowing for flexible color adjustment without compromising the harmonious color transition, thereby improving the production and appearance of dental restorations.
Implementation Method 1
blocks are generally prefabricated and are presintered, for example at a temperature of approximately 900° C. to 1100° C.
Implementation Method 2
When producing the shaped article, account has to be taken of the shrinkage that occurs in dense sintering.
Data Source
AI summary
The invention relates to a block (10) made of ceramic compounds, in particular dental compounds, of at least one ceramic compound (15) with predetermined first optical properties and at least a second ceramic compound (17) with predetermined second optical properties, and of a transition area between the two ceramic compounds, which transition area is composed of changing mixtures of the at least two ceramic compounds, the variation gradient of the mixtures being substantially constant. The invention further relating to a process for making such a block.