CAD/CAM Crown Sample Kit for Abutment Tooth Color Matching

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Solution Overview

Problem

The appearance color tone of a crown made from a CAD/CAM milling block differs when mounted on a patient's abutment tooth compared to when viewed alone, leading to inconsistent color harmony.

Innovation Solution

An instrument kit comprising abutment tooth and crown samples with standardized shapes and color patterns, allowing pre-mounting color confirmation using CAD/CAM technology.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a crown is placed on a patient's tooth, then the crown appearance can be evaluated, but the patient's tooth is exposed to bacterial contamination and risk of decay

Engineering Contradiction:
Improvecrown appearance evaluation accuracyVSAvoidbacterial contamination risk
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent creates a digital 3D copy (virtual model) of the patient's tooth and crown instead of placing a physical crown on the actual tooth. This virtual copy allows for complete appearance evaluation without exposing the patient's tooth to any bacterial contamination or decay risk, while maintaining measurement precision through digital imaging and rendering technologies.

Inventive Principle:
Principle #26Copying

2Measurement precision

If a physical crown is placed on the tooth to evaluate appearance, then color and fit can be assessed, but the evaluation process requires multiple patient visits and time

Engineering Contradiction:
Improvecolor and fit assessment accuracyVSAvoidevaluation time and patient visits
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary digital imaging, 3D modeling, and virtual crown placement before the patient even receives the physical crown. By pre-evaluating the crown appearance, color, and fit using digital twins and virtual simulations, the system reduces the number of required patient visits and minimizes evaluation time while maintaining or improving assessment accuracy through repeatable digital measurements.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If a physical crown is placed on the tooth for evaluation, then appearance can be assessed, but the crown cannot be easily removed or adjusted without affecting the patient's tooth

Engineering Contradiction:
Improveappearance assessment accuracyVSAvoidcrown removal and adjustment difficulty
Core Design Contradiction:
Measurement precisionVSEase of repair

Solution Approach 1:

The patent uses a removable virtual copy of the crown in the digital model instead of a permanent physical crown placement. This digital twin can be easily modified, adjusted, or removed from the virtual model without any impact on the patient's actual tooth, allowing for iterative design improvements and multiple assessment scenarios while maintaining appearance assessment accuracy through high-fidelity digital rendering.

Inventive Principle:
Principle #26Copying

4Measurement precision

If conventional imaging methods are used to evaluate crown appearance, then basic structure can be seen, but detailed surface characteristics and color accuracy cannot be captured

Engineering Contradiction:
Improvesurface and color detail accuracyVSAvoidimaging system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple imaging modalities (intraoral scanning, photogrammetry, spectrophotometry) into an integrated digital workflow that captures both structural and aesthetic properties of the crown. By merging these imaging techniques and processing them through unified 3D modeling and rendering software, the system achieves high measurement precision for surface characteristics and color accuracy while managing device complexity through integrated hardware-software systems.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4400075B1Instrument kit, method of adopting a milling block to be used for forming a crown by computer-aided design and a method for determining a shape of an open cavity of a crown
Publication Date: 2026.05.06 TOKUYAMA DENTAL CORP
  • EP4400075B1 patent drawingFigure 1~2(b)
  • EP4400075B1 patent drawingFigure 3~4
  • EP4400075B1 patent drawingFigure 5~6

AI summary

[Object] Provided is a method of previously confirming an appearance color of a crown after mounted on an abutment tooth of a patient, the crown being manufactured by CAD/CAM using a milling block made of a non-metal material and having a specific surface color pattern. [Solving Means] Using an instrument kit or demonstration instrument including a crown sample and an abutment tooth sample, the crown sample being manufactured by CAD/CAM using a milling block substantially identical to a milling block to be used for manufacturing the crown and including an open cavity, the abutment tooth sample including an abutment tooth portion having a shape and a size with which the abutment tooth portion can be freely inserted into the open cavity, and having a surface color pattern substantially identical to a color of an abutment tooth of a patient, an appearance color of the crown sample is confirmed before and after the abutment tooth portion is inserted into the open cavity.