Oblique-Layer Dental Blank for Natural Tooth Color Gradients
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Solution Overview
Problem
Existing dental blanks face challenges in replicating the natural tooth color and translucency gradient without visible layer boundaries, require complex layering processes, and suffer from sintering-induced shrinkage and mechanical weakness.
Innovation Solution
A dental blank with two obliquely layered glass, glass-ceramic, or ceramic layers that mimic the color and translucency gradient of natural teeth, allowing for simple shaping and conversion to high-strength restorations without visible boundaries, using materials like lithium silicate glass-ceramic or silicon dioxide glass-ceramic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple layers are layered on top of each other to eliminate visible interfaces, then the natural color and translucency gradient can be reproduced, but the device complexity and manufacturing process become more complex
Solution Approach 1:
The blank is divided into multiple layers with different colors and translucency values, where each layer represents a specific region of a natural tooth (enamel, dentin, cementum). This segmentation allows the color and translucency gradient to be reproduced through the stacking of discrete layers rather than requiring complex continuous filling processes.
Solution Approach 2:
Instead of using complex filling devices to create continuous gradients, the patent uses a systematic approach of stacking multiple discrete layers in the vertical dimension. Each layer contributes to the overall gradient effect, transforming a complex continuous problem into a manageable discrete layering problem.
2Strength
If sintering is applied to achieve high strength in dental restorations, then the mechanical strength is improved, but significant shrinkage occurs that complicates the production process
Solution Approach 1:
The blank is pre-formed with the correct geometry and color gradient before sintering. By establishing the precise shape and multi-layer structure in the green state, the subsequent sintering process only needs to densify the material without causing dimensional changes that would affect the final restoration fit.
Solution Approach 2:
The patent changes the material parameters by using glass-ceramic compositions with controlled crystallization behavior. Through specific heat treatment regimes, the material transforms from a glassy matrix to a glass-ceramic with enhanced strength while maintaining minimal shrinkage, thus achieving high strength without the harmful effects of conventional sintering.
3Device complexity
If monochrome glass-ceramic blocks are used to avoid sintering shrinkage, then the production process is simplified, but the natural tooth appearance cannot be replicated
Solution Approach 1:
Different regions of the blank are assigned different optical properties through the multi-layer structure. The enamel layer has high translucency and light color, the dentin layer has intermediate properties, and the cementum layer has low translucency and darker color. This local differentiation of material properties enables realistic tooth appearance while maintaining a relatively simple single-step sintering process.
Solution Approach 2:
The blank is constructed as a composite structure with multiple layers of glass-ceramic materials, each layer having specific color and translucency characteristics. This composite approach allows the replication of natural tooth appearance through the combination of different material properties rather than requiring complex processing of monochrome materials.
4Ease of manufacture
If horizontally layered blocks are used to imitate posterior teeth, then the production is simplified, but the appearance of anterior teeth with translucent enamel cannot be reproduced
Solution Approach 1:
The boundary surfaces between layers are designed with curved transitions rather than sharp horizontal interfaces. The enamel-dentin and dentin-cementum boundaries feature gradual curvature changes that mimic the natural transitions in tooth structure, enabling realistic anterior tooth appearance while maintaining manufacturability through controlled layering processes.
Data Source
AI summary
The present invention relates to a blank for dental purposes which has a first and a second layer which, independently of each other, are based on glass, glass-ceramic or ceramic, wherein the first layer and the second layer differ in colour and form a boundary surface, wherein the boundary surface runs obliquely.