Calcium Phosphate-Sulfate Bone Cement with Ammonium Setting Liquid
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Solution Overview
Problem
Conventional bone cements exhibit low bioresorption rates, high dissolution rates, and inadequate mechanical strength, which hinder their effectiveness in orthopedic and dental applications, and they often have prolonged setting times that complicate their use.
Innovation Solution
A calcium phosphate-calcium sulfate composite bone cement formula with an adjustable bioresorption rate, enhanced mechanical strength, and a controlled setting time is developed by using a specific ratio of tetracalcium phosphate, dicalcium phosphate, and calcium sulfate hemihydrate, along with an ammonium ion-based setting liquid, and incorporating a pore-forming agent to create a porous structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If calcium phosphate is used as bone cement, then mechanical strength and biocompatibility are improved, but bioresorption rate becomes too low
Solution Approach 1:
The patent uses a composite material system combining calcium phosphate (providing strength and biocompatibility) with calcium sulfate (providing controlled bioresorption). This composite approach allows the material to simultaneously achieve high mechanical strength and appropriate bioresorption rates, resolving the contradiction between these two properties.
2Loss of substance
If calcium sulfate is used as bone cement, then bioresorption rate is improved, but mechanical strength becomes too low
Solution Approach 1:
The patent combines calcium sulfate (providing controlled bioresorption) with calcium phosphate (providing mechanical strength) in a composite formulation. This synergistic combination allows the material to achieve both appropriate bioresorption rates and sufficient mechanical strength, resolving the contradiction between these properties.
3Ease of operation
If conventional bone cement paste is used, then ease of application is maintained, but setting time becomes too prolonged
Solution Approach 1:
The patent modifies the chemical composition parameters of the bone cement paste by incorporating specific ratios of calcium phosphate and calcium sulfate, along with appropriate setting agents. This parameter optimization enables the paste to maintain ease of application while significantly reducing setting time to a clinically acceptable range.
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 composite bone cement demonstrates improved bioresorbability, mechanical strength, and adjustable resorption rates, allowing for faster bone growth and enhanced clinical applicability, while maintaining cytotoxicity within safe limits.
Implementation Method 1
a calcium phosphate-calcium sulfate composite bone cement formula... The powder component includes a calcium sulfate source and a calcium phosphate source... The setting liquid component includes ammonium ion
Implementation Method 2
immersing said block of hardened bone cement composite with the pore-forming agent embedded therein in an immersing liquid to dissolve said pore-forming agent in the immersing liquid, creating pores therein
Data Source
AI summary
The present invention provides a bone cement formula having a powder component and a setting liquid component, wherein the powder component includes a calcium sulfate source and a calcium phosphate source with a weight ratio of the calcium sulfate source less than 65%, based on the total weight of the calcium sulfate source and the calcium phosphate source, and the setting liquid component comprises ammonium ion (NH4+) in a concentration of about 0.5 M to 4 M, wherein the calcium phosphate source includes tetracalcium phosphate (TTCP) and dicalcium phosphate in a molar ratio of TTCP to dicalcium phosphate of about 0.5 to about 2.5, and the calcium sulfate source is calcium sulfate hemihydrate (CSH), calcium sulfate dehydrate (CSD), or anhydrous calcium sulfate.