Gradient Translucency in Zirconia Dental Restorations
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Solution Overview
Problem
Zirconia dental materials have poor light-transmission properties and inadequate translucency, requiring ceramic veneers for aesthetic purposes, which lead to increased abutment space and poor bond strength, resulting in high failure rates and aesthetic issues.
Innovation Solution
A method involving dipping or brush-coating pre-sintered zirconia with a soluble yttrium salt solution, followed by sintering, to achieve a mixture of tetragonal and cubic phases, enhancing both strength and translucency, thereby eliminating the need for ceramic veneers and achieving a natural, gradient-like translucency similar to natural teeth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If zirconia ceramics are used for anterior teeth restoration, then mechanical strength is improved, but translucency deteriorates
Solution Approach 1:
The patent applies local quality by creating a gradient structure where the incisal portion has higher yttria content (8-10 wt%) for enhanced translucency, while the cervical portion maintains lower yttria content (3-5 wt%) for optimal strength. This spatial variation in composition allows each region to have properties optimized for its specific functional requirements.
Solution Approach 2:
The patent creates a composite zirconia material with non-uniform yttria distribution, forming a gradient composite structure. The material transitions from a stronger, less translucent composition at the base to a more translucent, slightly softer composition at the incisal edge, effectively combining the benefits of both material characteristics in a single restoration.
2Illumination intensity
If ceramic veneer is applied to improve translucency, then aesthetic appearance is improved, but bond strength deteriorates
Solution Approach 1:
The patent extracts and eliminates the ceramic veneer layer entirely by achieving the desired translucency through internal modification of the zirconia material itself. By creating a translucent incisal portion through yttria concentration gradient, the restoration achieves aesthetic appearance without requiring an additional veneer layer, thereby avoiding bond strength issues.
Solution Approach 2:
The patent utilizes color and translucency changes within the zirconia material itself by varying yttria concentration. The incisal portion's higher yttria content creates natural translucency and color gradient effects, mimicking real tooth appearance without external veneers.
3Ease of manufacture
If uniform yttria content is used in zirconia, then manufacturing simplicity is maintained, but aesthetic appearance deteriorates
Solution Approach 1:
The patent applies local quality by creating a gradient structure where the incisal portion has higher yttria content (8-10 wt%) for enhanced translucency, while the cervical portion maintains lower yttria content (3-5 wt%) for optimal strength. This spatial variation in composition allows each region to have properties optimized for its specific functional requirements.
4Illumination intensity
If zirconia with higher translucency is used, then aesthetic appearance is improved, but mechanical strength deteriorates
Solution Approach 1:
The patent applies local quality by creating a gradient structure where the incisal portion has higher yttria content (8-10 wt%) for enhanced translucency, while the cervical portion maintains lower yttria content (3-5 wt%) for optimal strength. This spatial variation in composition allows each region to have properties optimized for its specific functional requirements.
Solution Approach 2:
The patent creates a composite zirconia material with non-uniform yttria distribution, forming a gradient composite structure. The material transitions from a stronger, less translucent composition at the base to a more translucent, slightly softer composition at the incisal edge, effectively combining the benefits of both material characteristics in a single restoration.
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 provides zirconia dental restorations with improved translucency and strength, reducing veneer peeling and breaking issues, while maintaining cost-effectiveness and quality consistency, and allowing for a natural appearance and color gradient effects.
Implementation Method 1
3Y-TZP is a tetragonal phase which exists phase transformation toughening. The content of Y is increased by dipping in or brush-coating with an yttrium salt solution, and a mixture material comprising tetragonal and cubic phases with high strength and high translucency is obtained.
Implementation Method 2
Sintering: sintering the dried pre-sintered zirconia at 1400∼1600°C for 2 hours in a high temperature box resistance fumance
Data Source
AI summary
The present invention relates to a method for changing translucency of zirconia dental materials through applying an yttrium or ytterbium salt solution onto a pre-sintered zirconia material by dipping or brush-coating. Accordingly, the need of young patient in relation to the translucent requirement for incisal portion of anterior teeth is met in which the translucent level from the crown neck to the incisal portion is gradually changed in a natural manner, similar to natural teeth. A color gradient effect of the crown is produced through dipping in or brush-coatinging with yttrium or ytterbium salt solution. Moreover, the present invention involves simple operating steps and low cost while providing high consistency in quality.