Layered Ceramic Blanks With Preformed Through-Holes for Dental Use

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Solution Overview

Problem

Existing methods for producing dental restorations from zirconium dioxide blanks are time-consuming and do not ensure that the restorations meet aesthetic and strength requirements, particularly under severe loads, and the attachment process is laborious.

Innovation Solution

A method involving the use of a movable pin to create a through-hole in a ceramic material, allowing multiple layers of different compositions to be pressed and optionally sintered, with controlled thermal expansion coefficients and color properties to achieve high strength and translucency, simplifying the production process and attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If manual veneer application and fusing processes are used to produce dental restorations, then aesthetic requirements can be met, but the production process becomes time-consuming and laborious

Engineering Contradiction:
Improveaesthetic requirementsVSAvoidproduction time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention pre-forms the through-hole and multi-layer structure during the initial pressing and sintering of the zirconium dioxide blank, before any aesthetic veneer application. This preliminary structuring eliminates the need for time-consuming manual veneer application and fusing processes, as the restoration framework is already optimized for both strength and aesthetics prior to final processing

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention divides the zirconium dioxide blank into multiple layers with different compositions and properties during the pressing stage. By segmenting the material into distinct layers (e.g., different yttrium oxide percentages, different crystal phase compositions) before sintering, the process enables differentiated functional zones that meet both structural and aesthetic requirements without requiring post-sintering manual assembly

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If conventional pressing methods are used to form zirconium dioxide blanks, then the blank can be produced, but the attachment process remains laborious and post-processing steps are extensive

Engineering Contradiction:
Improveblank productionVSAvoidpost-processing steps
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The movable pin is inserted into the die cavity before the zirconium dioxide material is pressed in, so that the through-hole is pre-formed during the pressing stage itself. This preliminary formation of the through-hole eliminates the need for subsequent drilling, tapping, or other post-sintering hole creation operations, significantly reducing post-processing complexity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention combines multiple operations into a single pressing and sintering cycle: the through-hole formation, multi-layer structure creation, and blank sintering are all accomplished simultaneously or in sequence during one integrated process. The movable pin serves multiple functions (defining hole geometry, supporting material distribution, maintaining layer separation) that would otherwise require separate operations

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If single-layer zirconium dioxide blanks are used, then the production process is simple, but the restorations do not meet strength requirements under severe loads

Engineering Contradiction:
Improveproduction simplicityVSAvoidload-bearing strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The invention creates a composite structure within the zirconium dioxide blank by pressing multiple layers with different compositions (e.g., varying yttrium oxide percentages, different stabilizing agent contents, different crystal phase ratios) onto each other before sintering. This composite arrangement allows different regions to contribute different properties (strength, toughness, translucency) to achieve overall superior load-bearing capacity while maintaining manufacturing simplicity

Inventive Principle:
Principle #40Composite materials

4Manufacturing precision

If multi-layer blanks with different compositions are pressed and sintered, then strength and aesthetic requirements are met, but the process complexity increases

Engineering Contradiction:
Improvestrength and aesthetic propertiesVSAvoidpressing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The movable pin performs multiple functions simultaneously: it defines the through-hole geometry, supports the distribution of powder material during pressing, maintains separation between layers, and ensures proper alignment of the multi-layer structure. This single multi-functional element simplifies the overall device complexity compared to using separate tools for each function

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enables the production of dental restorations with improved strength and aesthetic properties, reducing post-processing steps and facilitating easier attachment, while maintaining high mechanical integrity under load.

Implementation Method 1

A layer of first ceramic material is filled into the cavity and around the movable pin to form a first layer. The movable pin is extended into the cavity either prior to, during, or after filling the cavity with the first ceramic material

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

The first and second ceramic materials are pressed together to form a compacted multi-layer blank with a through-hole extending through both layers

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

The compacted multi-layer blank is then sintered through to form a sintered multi-layer blank with a through-hole extending through both sintered layers

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP4472562B1Method for producing a multi-layer blank with a through-hole
Publication Date: 2025.10.15 DENTSPLY SIRONA INC
  • EP4472562B1 patent drawingFigure 1A
  • EP4472562B1 patent drawingFigure 1B
  • EP4472562B1 patent drawingFigure 1C

AI summary

A method for forming a multi-layer blank of a ceramic material including the steps of: providing a mold that includes at least one side wall surrounding a lower press plunger to form a cavity therebetween, wherein the lower press plunger has a movable pin; filling into the mold a first ceramic material; extending the movable pin from an upper surface of the lower press plunger and into the cavity; pressing a first upper press plunger against the first ceramic material so that a first open cavity is formed while at least a portion of the first upper press plunger is in contact with the movable pin to maintain the through-hole through the first layer; filling into the mold a second ceramic material of a different composition; extending the movable pin from an upper surface of the first layer and into the first open cavity; and pressing a second upper press plunger against the second layer so that a second open cavity is formed in communication with the through-hole that extends through the first and second layers to form the blank.