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Frozen delivery of brushite calcium phosphate cements

Paper ID Volume ID Publish Year Pages File Format Full-Text
1765 90 2008 8 PDF Available
Title
Frozen delivery of brushite calcium phosphate cements
Abstract

Calcium phosphate cements typically harden following the combination of a calcium phosphate powder component with an aqueous solution to form a matrix consisting of hydroxyapatite or brushite. The mixing process can be very important to the mechanical properties exhibited by cement materials and consequently when used clinically, since they are usually hand-mixed their mechanical properties are prone to operator-induced variability. It is possible to reduce this variability by pre-mixing the cement, e.g. by replacing the aqueous liquid component with non-reactive glycerol. Here, for the first time, we report the formation of three different pre-mixed brushite cement formulations formed by freezing the cement pastes following combination of the powder and liquid components. When frozen and stored at −80 °C or less, significant degradation in compression strength did not occur for the duration of the study (28 days). Interestingly, in the case of the brushite cement formed from the combination of β-tricalcium phosphate with 2 M orthophosphoric acid solution, freezing the cement paste had the effect of increasing mean compressive strength fivefold (from 4 to 20 MPa). The increase in compression strength was accompanied by a reduction in the setting rate of the cement. As no differences in porosity or degree of reaction were observed, strength improvement was attributed to a modification of crystal morphology and a reduction in damage caused to the cement matrix during manipulation.

Keywords
Calcium phosphate cement; Ceramic structure; XRD (X-ray diffraction); Brushite; Bone repair
First Page Preview
Frozen delivery of brushite calcium phosphate cements
Publisher
Database: Elsevier - ScienceDirect
Journal: Acta Biomaterialia - Volume 4, Issue 6, November 2008, Pages 1916–1923
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering