Ceramic Dental Abutment Fillet Design for Fracture Resistance

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Solution Overview

Problem

Metal dental abutments are aesthetically undesirable due to their visibility through thin gum tissue and are prone to exposure, while ceramic abutments are brittle and challenging to design for structural integrity.

Innovation Solution

A ceramic dental abutment with a fillet at the interface between the head portion and the anti-rotation feature, featuring a closed perimeter and a concave curvature to reduce stress concentrations and prevent fracture, and a radial dimension of at least 0.1 mm to enhance durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metal abutments are used, then structural strength is ensured, but aesthetic appearance deteriorates due to visibility through soft tissue

Engineering Contradiction:
Improvestructural strengthVSAvoidaesthetic appearance
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The abutment is constructed as a composite structure combining metal and ceramic materials. The metal core provides structural strength and rigidity, while the ceramic coating layer provides aesthetic appearance by matching natural tooth color and blocking visibility through soft tissue. This composite approach resolves the contradiction between strength and aesthetics.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If ceramic abutments are used, then aesthetic appearance is improved, but structural strength deteriorates due to brittleness

Engineering Contradiction:
Improveaesthetic appearanceVSAvoidstructural strength
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The abutment uses a composite structure with a metal core providing structural strength and a ceramic outer layer providing aesthetic appearance. The metal substrate prevents catastrophic failure while the ceramic coating delivers natural tooth-like appearance, resolving the strength-aesthetics contradiction.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different regions of the abutment have different material properties: the core region uses metal for strength and load-bearing, while the outer surface uses ceramic for aesthetics. This local differentiation of material quality allows simultaneous optimization of both strength and appearance.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If sharp corners are present at the interface between head portion and anti-rotation feature, then manufacturing is simplified, but stress concentration increases leading to fracture risk

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidfracture resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The fillet replaces sharp corners with curved surfaces at the interface between the head portion and anti-rotation feature. This curvature eliminates stress concentration points while maintaining manufacturability through standard fillet operations, resolving the contradiction between manufacturing simplicity and fracture resistance.

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Reliability

If fillet radius is increased to reduce stress concentration, then fracture resistance is improved, but manufacturing precision requirements worsen

Engineering Contradiction:
Improvefracture resistanceVSAvoidfillet dimension control
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent specifies an optimized fillet radius range (0.05-0.15 inches) that balances stress reduction with manufacturability. This parameter optimization ensures adequate fracture resistance while remaining within standard manufacturing capabilities, resolving the contradiction between reliability and manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2136730B1Dental abutment including fillet
Publication Date: 2016.08.03 DENTSPLY IH AB
  • EP2136730B1 patent drawingFigure 1~2
  • EP2136730B1 patent drawingFigure 3~4
  • EP2136730B1 patent drawingFigure 5

AI summary

Exemplary embodiments relate to a dental abutment and methods of forming the same. The abutment (19) may include a head portion (27) located at an upper end of the abutment and constructed to support a prosthetic tooth replacement and soft tissue adjacent the head portion, an anti-rotation feature (25) located at a lower end of the abutment and constructed to mate with a dental implant, and a fillet (21) located at an interface between the head portion and the anti-rotation feature. The fillet may reduce a risk of fracture at the interface between the head portion and the anti-rotation feature. In some examples, the abutment may be formed at least partially of a ceramic material.