Dental Cement System with Chelating Agent for Stable Setting

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Solution Overview

Problem

Dental and orthopedic cement systems require improved bioactivity, reduced microleakage, and stable setting properties while maintaining rapid hardening and corrosion resistance, which existing materials fail to consistently achieve across a wide powder-to-liquid ratio range.

Innovation Solution

A cement system comprising 40-60 wt % calcium aluminate, 8-15 wt % polyacrylic acid, 0.5-5 wt % tartaric acid, 25-45 wt % strontium-fluoro-alumino-silicate glass, and 2.5-10 wt % strontium fluoride, mixed with an aqueous hydration liquid containing deionized water and a Ca2+ scavenging chelating agent like Na3-NTA, allowing for robust properties and compliance with ISO 9917:2003 standards across various ratios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If rapid hardening is achieved, then setting time is reduced, but heat generation increases and may cause detrimental effects

Engineering Contradiction:
Improvesetting timeVSAvoidheat generation
Core Design Contradiction:
Loss of timeVSTemperature

Solution Approach 1:

The patent modifies the chemical composition parameters of the cement system by incorporating specific ratios of calcium aluminate, polyacrylic acid, tartaric acid, and strontium-fluoro-alumino-silicate glass. This compositional adjustment enables the system to achieve rapid setting while controlling the exothermic reaction through the buffering effect of the glass phase and organic acid components, thus resolving the contradiction between fast setting and heat generation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite cement system combining inorganic calcium aluminate with organic polyacrylic acid and tartaric acid, along with strontium-fluoro-alumino-silicate glass. This composite structure allows the inorganic phase to provide rapid hardening while the organic and glass phases moderate the heat of reaction, achieving both quick setting and controlled temperature rise

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If powder to liquid ratio is varied to optimize properties, then material adaptability improves, but setting time and film thickness control becomes difficult

Engineering Contradiction:
Improvepowder to liquid ratio rangeVSAvoidsetting time control
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent designs a universal cement system where the strontium-fluoro-alumino-silicate glass phase and chelating agents create a buffer zone that maintains stable setting characteristics across a broad powder-to-liquid ratio range (2.8:1 to 3.5:1). This multi-functional formulation allows the same mix design to adapt to different handling requirements while maintaining consistent setting behavior, eliminating the need for precise ratio control

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

3Manufacturing precision

If film thickness is reduced to meet low demands, then bonding precision improves, but setting time increases and handling becomes difficult

Engineering Contradiction:
Improvefilm thicknessVSAvoidsetting time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent adjusts the chemical parameters by incorporating tartaric acid and polyacrylic acid in specific amounts (0.5-5 wt% and 8-15 wt% respectively) which modify the setting kinetics. These compositional changes enable the cement to set rapidly even when applied in thin films, decoupling the relationship between film thickness and setting time that typically exists in conventional cements

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 system exhibits improved bioactivity, minimal microleakage, and stable net setting time, film thickness, and compressive strength, enabling its use in dental luting cements for thin layers with enhanced long-term stability and bioactivity, suitable for use with capsule mixing systems.

Implementation Method 1

an aqueous hydration liquid based on deionized water... containing a Ca2+ scavenging chelating agent like Na3-NTA

Methodology Applied
Scientific EffectChelation:

Implementation Method 2

a powdered material that essentially consists of an inorganic cement system, which powdered material has the capacity to form a complex, chemically bonded material with inorganic as well as organic phases

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 3

an aqueous hydration liquid based on deionized water... stable net setting time

Methodology Applied
Scientific EffectHydration: Mineral Hydration

Data Source

PatentUS7867329B2Dental cement system, a powdered material and a hydration liquid therefor, and ceramic material formed therefrom
Publication Date: 2011.01.11 DOXA AB

AI summary

A dental cement system, including an aqueous hydration liquid and a powdered material that essentially consists of an inorganic cement system, which powdered material has the capacity to form a complex, chemically bonded material with inorganic as well as organic phases with properties suitable for cementation of implant to another implant and/or to tooth or bone tissue.