Calcium Phosphate Silicate Cement Strength and Bioactivity
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Solution Overview
Problem
Current hydraulic cements, such as Ordinary Portland Cement (OPC), face challenges with low mechanical strength, high calcium hydroxide content, and environmental sensitivity, which affect their durability and compatibility in medical and dental applications.
Innovation Solution
Development of Calcium Phosphate Silicate Cement (CPSC) compositions that incorporate phosphate compounds and calcium silicates, allowing for in-situ precipitation of hydroxyapatite, which replaces calcium hydroxide, enhancing mechanical strength, bioactivity, and biocompatibility, while maintaining adjustable setting times and low hydration heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If phosphate compounds are added to hydraulic cement, then mechanical strength and bioactivity are improved, but setting time control becomes more difficult
Solution Approach 1:
The patent adjusts the chemical composition parameters of the cement system by controlling the ratio of calcium phosphate to calcium silicate, the fineness of grinding, and the water-cement ratio to optimize both strength development and setting time. Specific parameter ranges are provided to achieve desired performance characteristics.
Solution Approach 2:
The patent introduces calcium silicate as an intermediary component that moderates the rapid setting tendency of calcium phosphate cement. The calcium silicate hydrate formation acts as a buffer that controls the overall setting kinetics while contributing to final strength.
2Reliability
If calcium phosphate is used to replace calcium hydroxide, then bioactivity and biocompatibility are enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent creates a composite cement system combining calcium phosphate and calcium silicate components in specific proportions. This composite approach achieves enhanced bioactivity while maintaining manufacturability through established cement production techniques.
Solution Approach 2:
The patent designs a multi-functional cement material that simultaneously provides structural strength, bioactivity, biocompatibility, and controlled setting characteristics. The dual-component system performs multiple functions that would otherwise require separate materials or complex processing steps.
3Reliability
If phosphate compounds are incorporated into cement composition, then corrosion resistance is improved, but hydration heat increases
Solution Approach 1:
The patent modifies the chemical composition parameters to balance corrosion resistance and hydration heat. By optimizing the calcium phosphate content and particle size distribution, the cement achieves improved corrosion resistance while the specific composition formulation moderates the hydration heat generation.
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
CPSC exhibits significantly improved mechanical strength, corrosion resistance, and bioactivity, making it suitable for both structural and medical applications, with enhanced compatibility with living tissues and reduced environmental impact.
Implementation Method 1
the present invention decreases the final content of CH in the set cement, thus resulting in a significantly increased durability and strength... by reactively precipitating calcium phosphates, in particular hydroxyapatite
Implementation Method 2
The mechanism of improvement depends on the silica fume reacting with calcium hydroxide to produce an amorphous C—S—H gel... The present invention discloses an alternative method of in-situ removal of CH from setting cement, by reactively precipitating calcium phosphates
Data Source
AI summary
A hydraulic cement comprising a calcium silicate and at least one phosphate compound. The phosphate compound is included in an amount sufficient to react a major portion of the calcium hydroxide that is produced during hydration of the cement to hydroxyapatite or other calcium phosphates. The phosphate compound is preferably a mono-calcium phosphate. The cement is useful in both bio-medical/dental and engineering applications. The calcium hydroxide is reacted by the phosphate to form hydroxiapatite or other calcium phosphate that is co-precipitated with the calcium silicate hydrate to form a composite-like structure on a nano-scale level. The reduced calcium hydroxide content in the set cement increases its strength and reduces its pH. The hydroxiapatite content and the reduced pH render the cement bio-active and suitable for use in medical and dental implants, for example, for replacement bone and tooth material. Due to its high strength, the cement may also be used for structural/engineering applications.