Gradient Zirconia Dental Ceramics Without Layer Demarcation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Zirconia-based dental materials, particularly uncolored ones, have low translucency and esthetic issues, leading to unnatural tooth color and demarcations in layered materials that fail to replicate natural teeth aesthetics.
Innovation Solution
Developed pre-sintered and sintered zirconia dental ceramic materials with a smooth gradient transition of translucency and color between dentin and incisal regions, utilizing a transition zone with a continuous yttria content gradient, eliminating observable layers or demarcations, and maintaining high biaxial flexural strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If layered zirconia materials are used to improve esthetics, then color and translucency variation is achieved, but observable demarcation between layers occurs
Solution Approach 1:
The patent applies parameter changes by creating a continuous gradient in yttria concentration (compositional parameter) across the zirconia material. Instead of discrete layers with abrupt transitions, the yttria content varies continuously from one region to another, producing a smooth gradient in translucency and color without observable demarcation lines. This resolves the contradiction by transforming the abrupt parameter changes in layered materials into continuous parameter variations.
Solution Approach 2:
The patent implements local quality by assigning different yttria concentrations to different regions of the zirconia material to achieve spatial variation in optical properties. The incisal region has higher yttria content for greater translucency, while the dentin region has lower yttria content for appropriate color, with a continuous gradient in between. This local differentiation of composition creates natural-looking esthetics without the harsh boundaries of layered structures.
2Illumination intensity
If gradient transition zone is introduced to eliminate layer demarcation, then esthetics is improved, but material complexity increases
Solution Approach 1:
The patent employs composite materials by combining zirconia particles with different yttria concentrations within a single monolithic structure. Rather than assembling separate layered components, the gradient composition is achieved through controlled distribution of yttria-doped zirconia particles or through compositional grading during sintering. This composite approach creates the desired optical gradient while maintaining structural integrity and avoiding the complexity of multiple discrete layers.
3Illumination intensity
If yttria content is varied to achieve color gradient, then esthetics similar to natural teeth is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies preliminary action by pre-mixing zirconia powders with predetermined yttria concentrations and distributions before sintering. The gradient composition is established in the green body stage through careful powder blending and distribution, ensuring that the desired yttria gradient is achieved before the sintering process begins. This preliminary preparation simplifies the overall manufacturing process by separating the compositional design phase from the sintering phase, reducing the precision requirements during the actual forming process.
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 materials achieve esthetic similarity to natural teeth by providing a seamless transition in color and translucency without visible layers, while retaining the mechanical strength of zirconia.
Implementation Method 1
The present disclosure provides pre-sintered zirconia dental ceramic materials, sintered zirconia dental ceramic materials
Data Source
AI summary
Provided are pre-sintered and sintered zirconia dental ceramic materials. The materials have a gradient in yttria content. The materials may have a gradient in one or more physical/mechanical property and/or one or more optical property. The materials may be made by mixing at least two zirconia ceramic powders having different yttria content. A sintered zirconia dental ceramic material may be in the form of a dental article.