Reversible Dental Crown Framework with Macro-Retentive Veneer

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Solution Overview

Problem

Current dental prosthesis crowns and bridges have irreversibly connected components, making it impossible to remove the veneer without damaging the framework, leading to unsatisfactory repair options and increased risk of damage to implants due to the brittleness of ceramic veneers.

Innovation Solution

Design and manufacture of a crown or bridge with a macro-retentive composite system, allowing the veneer to be detached from the framework without damaging it, using CAD/CAM processes and materials like metals, plastics, and ceramics, with macro-retentive connections that enable easy replacement and integration of a new veneer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the components are irreversibly connected by sintering or gluing, then the structural stability is improved, but the ease of repair deteriorates because the veneer cannot be removed without damaging the framework

Engineering Contradiction:
Improvestructural stabilityVSAvoidease of repair
Core Design Contradiction:
Stability of the object's compositionVSEase of repair

Solution Approach 1:

The crown is divided into two separate components: a framework and a veneer. These components are connected through a retention system that allows the veneer to be detached and reattached. The framework contains retention elements (such as grooves, undercuts, or mechanical retention features) that engage with corresponding elements on the veneer, enabling reversible connection while maintaining structural stability during normal use.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection system transitions from a static irreversible bond to a dynamic reversible connection. The retention system allows the veneer to be removed and reattached multiple times through controlled mechanical engagement and disengagement, providing adaptability for repair and replacement while maintaining stability during functional loading.

Inventive Principle:
Principle #15Dynamics

2Strength

If ceramic veneers are used to avoid rapid wear and tear, then the hardness is improved, but the reliability deteriorates due to the brittleness of ceramic materials causing cracks and flaking

Engineering Contradiction:
ImprovehardnessVSAvoidreliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The crown is segmented into a framework and a veneer, where the framework provides structural support and the veneer provides aesthetic and wear-resistant surface properties. This segmentation allows the brittle veneer to be replaced if damaged, while the framework remains intact and can retain the same or a different veneer.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The material properties are optimized by selecting different materials for different functions: the framework uses materials with high toughness and ductility to absorb impact forces, while the veneer uses hard ceramic materials for wear resistance. The retention system parameters are designed to distribute stresses away from the veneer-f framework interface to prevent crack propagation.

Inventive Principle:
Principle #35Parameter changes

3Strength

If the veneer is made brittle to maintain hardness and wear resistance, then the hardness is improved, but the loss of substance increases when the veneer cracks and flakes off

Engineering Contradiction:
ImprovehardnessVSAvoidloss of substance
Core Design Contradiction:
StrengthVSLoss of substance

Solution Approach 1:

The design allows the veneer to be discarded when damaged and recovered by reattaching a new veneer to the retained framework. The retention system ensures that the framework remains intact and can be reused, minimizing material loss and waste compared to irreversible bonding methods where the entire crown must be replaced.

Inventive Principle:
Principle #34Discarding and recovering

4Ease of operation

If screw connections are used to allow reversible removal, then the ease of operation is improved, but the sealing deteriorates due to gaps in the screw connection area

Engineering Contradiction:
Improveease of operationVSAvoidsealing
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

A sealing element acts as an intermediary component between the screw connection and the internal cavity. This sealing element fills the gaps created by the screw connection, preventing fluid or debris penetration while allowing the screw to maintain the mechanical connection. The sealing element can be a gasket, O-ring, or sealing compound that conforms to the interface geometry.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2713937A1Composite crown/composite bridge and method for production thereof
Publication Date: 2014.04.09 SCHWEIGER JOSEF

AI summary

The invention relates to a new kind of tooth replacement crown and tooth replacement bridge, of which the components are a framework (3) and a veneer (4), which are reversibly connected to each other by a macro-retentive bonding system (5), and a method for producing the components, in which method these components are preferably produced by means of computer-aided design and computer-aided manufacturing.