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11:51
An Improved Mechanical Testing Method to Assess Bone-implant Anchorage
Published on: February 10, 2014
In situ study on the curing process of calcium phosphate bone cement
Yuxing Song1, Zude Feng, Ting Wang
1Department of Materials Science and Engineering, Xiamen University, Xiamen 361005, China.
Journal of Materials Science. Materials in Medicine
|February 6, 2007
Summary
This study monitored calcium phosphate bone cement (CPC) curing, revealing apatite formation occurs in two steps. The liquid phase significantly influences the reaction, with acidic conditions inhibiting complete apatite conversion.
Area of Science:
- Biomaterials Science
- Materials Chemistry
- Crystallography
Background:
- Calcium phosphate bone cements (CPCs) are vital for bone regeneration.
- Understanding the curing process and the role of the liquid phase is crucial for optimizing CPC performance.
- Modified alpha-TCP cement was investigated to elucidate its curing mechanisms.
Purpose of the Study:
- To comprehensively track the curing process of modified alpha-TCP cement.
- To investigate the influence of different aqueous liquid phases on the cement's curing reaction.
- To correlate chemical and physical changes during CPC setting.
Main Methods:
- In situ X-ray diffraction (XRD) for chemical reaction monitoring.
- pH testing to track changes in the local environment.
- Quantitative ultrasonic measurement (QUS) to assess physical property evolution.
- Analysis of speed of sound (SOS) and ultrasonic attenuation coefficient (UAC).
Main Results:
- CPC powders were fully consumed within 72 hours.
- Apatite formation proceeded in two distinct steps: initial carbonated hydroxyapatite (CHA) precipitation followed by calcium-deficient hydroxyapatite (CDHA) conversion.
- The presence of NaH2PO4 as a liquid phase inhibited complete apatite conversion due to an acidic environment.
- Ultrasonic parameters (SOS and UAC) quantitatively reflected apatite formation and microstructural changes, correlating with the transition from paste to solid.
- The curing mechanism followed a dissolution-precipitation model.
Conclusions:
- The liquid phase composition critically affects the extent of apatite formation in CPCs.
- Quantitative ultrasonic measurements provide valuable insights into the kinetics and mechanisms of CPC curing.
- Modified alpha-TCP cements exhibit a two-step apatite formation process governed by dissolution-precipitation.
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