Dental Ceramic Mixture Recipe Algorithm for Color Matching

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Solution Overview

Problem

Current methods for determining the exact color of dental ceramics for artificial restorations are error-prone and time-consuming, as they rely on visual comparisons and lack standardized shade standards, leading to inconsistent results across different manufacturers' materials.

Innovation Solution

A method involving specifying a target color using L* a* b* values, providing three stains (red, gray, and yellow) that change specific color components, and using an algorithm to calculate the mixing ratios of dentine ceramic and stains to achieve the desired color, ensuring accurate color reproduction in dental restorations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If visual comparison with standardized shade guides is used to determine tooth color, then the process is simple and quick, but the accuracy and reliability of color determination is poor due to lighting conditions, insufficient color coverage, and lack of uniform standards

Engineering Contradiction:
Improvespeed of color determinationVSAvoidaccuracy of color determination
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent replaces the manual visual comparison method with an automated spectrophotometric measurement system. The spectrophotometer objectively measures the L*, a*, and b* color values of teeth, eliminating subjective visual assessment and its associated errors from lighting conditions and observer variability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transforms color determination from qualitative visual assessment to quantitative parameter measurement. By converting color into numerical L*, a*, and b* values, the system enables precise, objective, and reproducible color data that can be directly used for ceramic mixing calculations.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If multiple raw materials from different manufacturers are mixed to achieve desired color, then the available material variety is extensive, but the time required to determine suitable mixture ratios is very long and the process is complex

Engineering Contradiction:
Improveavailability of raw materialsVSAvoidtime for mixture determination
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent performs preliminary color measurement of the natural tooth before the ceramic mixing process. By obtaining the target L*, a*, and b* values in advance, the system provides a clear quantitative target for the mixing process, eliminating the time-consuming trial-and-error approach.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent establishes a feedback loop where the measured tooth color values (L*, a*, b*) directly inform the ceramic mixing ratios. The algorithm uses these measured values to calculate the precise amounts of dentin ceramic and stains needed, creating a closed-loop system that reduces mixing time.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If classical shade matching methods are used, then the process is straightforward, but the correspondence between determined shade and actual achieved shade is insufficient to meet patient requirements

Engineering Contradiction:
Improvesimplicity of shade matchingVSAvoidcorrespondence between determined and achieved shade
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces subjective visual shade matching with objective spectrophotometric measurement and algorithm-based calculation. This substitution eliminates the variability and inaccuracy inherent in visual comparison while maintaining operational simplicity through automated measurement and computation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transforms the shade matching process from qualitative category matching to quantitative parameter calculation. By using L*, a*, and b* values as precise numerical targets, the system achieves reliable correspondence between the measured tooth color and the achieved ceramic color.

Inventive Principle:
Principle #35Parameter changes

4Adaptability or versatility

If stains are added to dentin ceramic to adjust color, then the color can be modified, but determining the precise ratios of multiple stains and ceramics is challenging and time-consuming

Engineering Contradiction:
Improvecolor adjustment capabilityVSAvoidcomplexity of mixing ratios
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent simplifies the complex multi-component mixing problem by transforming it into a calculation based on L*, a*, and b* parameter changes. Each stain and ceramic is characterized by its effect on these parameters, allowing the algorithm to determine precise ratios through mathematical calculation rather than complex manual mixing.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3616648B1Method for determining a mixture recipe for a dental ceramic with a desired colour
Publication Date: 2023.06.14 HEIN SASCHA
  • EP3616648B1 patent drawingFigure 1
  • EP3616648B1 patent drawingFigure 2

AI summary

A method for determining a mixture recipe for a dental ceramic with a desired color comprises the following steps: i) specifying the target color of the dental ceramic; ii) providing at least one dentin ceramic; iii) providing at least three different stains; iv) providing an algorithm designed to calculate a mixture recipe for a composition containing the at least one dentin ceramic provided in step ii) and the at least three stains provided in step iii) in such quantities that a dental ceramic produced from the composition has the target color specified in step a); and v) determining the mixture recipe for the dental ceramic by performing the algorithm.