Solid Freeform Fabrication Material Set for Dental Prosthetics

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Solution Overview

Problem

Current methods for manufacturing dental prosthetics, particularly those using zirconia, face challenges such as excessive abrasion, corrosion, aesthetic issues due to uniform coloring, and time-consuming processing requirements for achieving gradation and natural tooth-like appearance.

Innovation Solution

A solid freeform fabrication material set comprising a first liquid material with a solvent, resin A, and inorganic particles, and a second liquid material with resin B and colorants, allowing for precise control of color distribution and gradation through inkjet methods, enabling efficient manufacturing of dental prosthetics with high mechanical strength and natural tooth-like appearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If zirconia is used for dental prosthetics, then mechanical strength and corrosion resistance are improved, but aesthetic appearance deteriorates due to uniform milky white color

Engineering Contradiction:
Improvemechanical strengthVSAvoidaesthetic appearance
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The patent applies local quality by incorporating colorants into specific regions of the zirconia prosthetic structure. The colorant concentration varies spatially to create natural tooth-like gradation, with different colors applied to different areas (incisal, middle, gingival regions) to match natural tooth appearance while maintaining zirconia's mechanical properties throughout the structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent creates a composite material system by combining zirconia particles with colorants (metal oxides such as iron oxide, copper oxide, cobalt oxide) and binders. This composite approach allows the prosthetic to exhibit both the mechanical strength of zirconia and the aesthetic properties of colored regions, achieving a material that simultaneously provides structural integrity and natural appearance.

Inventive Principle:
Principle #40Composite materials

2Strength

If molding processing is used to manufacture zirconia prosthetics, then mechanical strength is improved, but manufacturing time increases due to time-consuming cutting and coloring processes

Engineering Contradiction:
Improvemechanical strengthVSAvoidmanufacturing time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The patent applies preliminary action by incorporating colorants directly into the zirconia material before the molding and sintering processes. This allows coloration to occur during fabrication rather than requiring separate post-processing coloring steps, significantly reducing manufacturing time while maintaining the mechanical strength achieved through proper sintering.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent merges multiple processes into one by combining the molding, coloring, and sintering operations. The colorant is mixed with the zirconia powder and binder, then all components are molded and sintered together in a single process sequence, eliminating the need for separate cutting and coloring operations that characterize traditional manufacturing methods.

Inventive Principle:
Principle #5Merging (Combining)

3Shape

If colorants are added to zirconia, then aesthetic appearance is improved, but color agglomeration occurs leading to non-uniform coloring

Engineering Contradiction:
Improveaesthetic appearanceVSAvoidcolor distribution uniformity
Core Design Contradiction:
ShapeVSManufacturing precision

Solution Approach 1:

The patent uses a binder as an intermediary substance that facilitates uniform dispersion of colorant particles throughout the zirconia matrix. The binder (such as polyvinyl alcohol, carboxymethyl cellulose, or starch) acts as a medium that prevents colorant agglomeration during mixing and maintains homogeneous distribution through the green body and sintered product, ensuring uniform coloration.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent controls color distribution uniformity by optimizing parameters including colorant particle size (0.1-10 micrometers), colorant concentration (1-20 wt%), and binder content. By carefully controlling these parameters, the patent prevents colorant agglomeration while achieving desired color intensity and uniform distribution in the final prosthetic.

Inventive Principle:
Principle #35Parameter changes

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 solution enables the stable and efficient production of dental prosthetics with non-white colorants, achieving high mechanical strength, natural appearance, and reduced processing time, while maintaining dimensional accuracy and preventing color agglomeration.

Implementation Method 1

applying a liquid material to a powder build material in a predetermined area by inkjet method

Methodology Applied
Scientific EffectInkjet printing:

Implementation Method 2

a binder is ejected onto a powdered build material

Methodology Applied
Scientific EffectBinder adhesion: Adhesive

Implementation Method 3

sintering the green body

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP3243500B1Solid freeform fabrication material set, method of manufacturing solid freeform fabrication object, and device for manufacturing solid freeform fabrication object
Publication Date: 2020.02.12 RICOH CO LTD
  • EP3243500B1 patent drawingFigure 1
  • EP3243500B1 patent drawingFigure 2
  • EP3243500B1 patent drawing

AI summary

A solid freeform fabrication material set includes a first solid freeform fabrication liquid material including a solvent, a resin A soluble in the solvent, and an inorganic particle; and a second solid freeform fabrication liquid material including a resin B soluble in water and a colorant.