Composite Inlay Kit for Chairside Production Without Surface Pretreatment

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Solution Overview

Problem

Conventional dental composite materials face challenges with polymerization shrinkage, leading to internal tensions, detachment from cavity walls, and marginal gaps, and require costly and labor-intensive CAD/CAM systems for indirect production methods, which are not accessible to all dental practices due to high investment costs and the need for mechanical pretreatment for adequate bonding.

Innovation Solution

A kit comprising polymerizable masses for producing denture models and composite inlays with high filler content, specific monomer ratios, and optional acid solutions for etching, allowing for chairside production of composite inlays with non-sandblasted, non-silanized, and non-primed surfaces, achieving high adhesive forces without the need for mechanical pretreatment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional (meth)acrylate-based filling plastics are polymerized directly in cavities, then the material can be applied and hardened in situ, but polymerization shrinkage causes internal tensions, detachment from cavity walls, and marginal gaps

Engineering Contradiction:
Improvedirect polymerization in cavityVSAvoidbonding to cavity walls
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent divides the restoration process into two separate stages: first, the cavity is filled with a polymerizable mass that is polymerized outside the cavity (in a model or laboratory setting); second, the resulting inlay is inserted into the cavity and bonded using a separate polymerizable attaching mass. This segmentation eliminates the polymerization shrinkage problems that occur when polymerizing directly in the cavity, while still allowing for in-situ bonding of the pre-formed inlay.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inlay is prepared and polymerized in advance, outside the oral cavity, before being inserted into the patient's mouth. The polymerizable mass for producing the inlay is prepared and polymerized in a model or laboratory setting before the final bonding step. This preliminary action allows for controlled polymerization without the constraints and problems of in-situ polymerization.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If CAD/CAM systems are used for indirect production of composite inlays, then high manufacturing precision and quality can be achieved, but the high investment costs and complexity make them inaccessible to many dental practices

Engineering Contradiction:
Improveindirect production qualityVSAvoidCAD/CAM system cost
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent employs a disposable, off-the-shelf polymerizable mass for producing inlays that can be mixed and used immediately without requiring expensive CAD/CAM equipment. The system uses conventional dental materials and simple mixing devices that are accessible to most dental practices, replacing the need for high-cost CAD/CAM systems while maintaining acceptable manufacturing precision through standardized formulations and procedures.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention uses a polymerizable mass that can be poured into a model or mold to create a replica of the desired inlay shape. This copying process allows for the production of precise inlays using simple molding techniques rather than complex CAD/CAM machining, making the technology accessible to dental practices without expensive equipment.

Inventive Principle:
Principle #26Copying

3Reliability

If mechanical pretreatment (sandblasting, silanization, priming) is applied to composite inlay surfaces, then adequate bonding to tooth structures is achieved, but the process becomes more complex and time-consuming

Engineering Contradiction:
Improveadhesive force to toothVSAvoidsurface treatment procedures
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The polymerizable attaching mass is formulated to be self-adhesive, eliminating the need for separate mechanical pretreatment steps such as sandblasting, silanization, or priming. The attaching mass contains adhesive components that automatically bond to the inlay surface and tooth structure without requiring additional surface preparation procedures, thereby simplifying the overall process while maintaining reliable bonding.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent combines the functions of multiple separate surface treatment steps (sandblasting, silanization, priming) into a single integrating step by using a polymerizable attaching mass that performs all these functions simultaneously. The attaching mass contains multiple functional components that work together to prepare and bond the surface in one application, reducing complexity and time.

Inventive Principle:
Principle #5Merging (Combining)

4Manufacturing precision

If high filler content is used in polymerizable masses for composite inlays, then polymerization shrinkage and deformation are minimized, but the material becomes more difficult to process

Engineering Contradiction:
Improvepolymerization shrinkage controlVSAvoidmaterial processability
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent carefully adjusts the parameters of the polymerizable mass formulation, including the type, size distribution, and concentration of fillers, to achieve the optimal balance between shrinkage control and processability. By controlling filler particle size (combining fine and coarse particles) and concentration (typically 60-85% by weight), the material maintains low shrinkage while retaining adequate flow and processing characteristics.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses composite materials with carefully designed filler compositions, combining different types of fillers (e.g., glass fibers, ceramic particles, metal oxides) with appropriate size distributions and surface treatments. This composite approach allows for optimized shrinkage control while maintaining processability through the synergistic effects of different filler types and their interactions with the polymer matrix.

Inventive Principle:
Principle #40Composite materials

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 kit enables the production of composite inlays with adhesive forces exceeding 8 MPa, minimizing polymerization shrinkage and deformation, and allowing for rapid, high-quality, cost-effective, and accessible indirect chairside production with reliable bonding to tooth structures.

Implementation Method 1

a polymerizable mass for producing a composite inlay, comprising B.b. a total amount of polymerizable monomers or monomer mixtures in the range from 3 to less than 25% by weight, based on the total mass of the polymerizable mass for producing a composite inlay B

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Implementation Method 2

an acid solution for etching the hard tooth substance is used to increase the adhesive force between the hard tooth structure and the fixing material

Methodology Applied
Scientific EffectEtching: Abrasion

Implementation Method 3

a polymerizable mass for attaching a crosslinked and non-sandblasted, non-silanized, non-etched, non-primed and non-roughened composite inlays in the cavity

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2716276B1Kit and method for indirect chair-side production of composite inlays
Publication Date: 2019.04.24 VOCO GMBH

AI summary

The present invention relates to a kit for the indirect fabrication of composite inlays comprising a polymerizable mass for fabricating a dental model, a polymerizable mass for fabricating an inlay, a polymerizable mass for cementing a cross-linked and non-sandblasted, non-silanized, non-etched, non-primed, and non-roughened composite inlay, the surfaces of which are fully polymerized, into the cavity, and optionally, if, for example, the polymerizable mass for cementing a cross-linked and non-sandblasted, non-silanized, non-etched, non-primed, and non-roughened composite inlay, the surfaces of which are fully polymerized, into the cavity is not self-adhesive, a polymerizable mass for increasing the bond strength between the polymerizable mass for cementing a cross-linked, non-sandblasted, non-silanized, non-etched,The invention relates to unprimed and unroughened composite inlays, the surfaces of which are fully polymerized, placed in the cavity and the tooth structure, and optionally, in the case of a polymerized mass, to increase the bond strength between the tooth structure and the luting material, an acid solution for etching the tooth structure. The invention further relates to methods for producing a composite inlay.