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High Early Strength Calcium Phosphate Bone Cement: Effects of Dicalcium Phosphate Dihydrate and Absorbable Fibers

Published

Author(s)

Elena F. Burguera, Hockin D. Xu, Shozo Takagi, Laurence C. Chow

Abstract

Calcium phosphate cement (CPC) sets in situ to form resorbable hydroxyapatite with chemical and crystallographic similarity to the carbonated apatite in human bones, hence is highly promising for clinical applications. The objective of the present study was to develop a CPC with fast setting and high strength in the early stage of implantation. Two approaches were combined to impart high early strength and toughness to the cement: the use of dicalcium phosphate dihydrate with a high solubility (which formed the cement CPCD) instead of dicalcium phosphate anhydrous (which formed the conventional cement CPCA), and the incorporation of absorbable fibers. To investigate the early strength and its dependence on incubation time (cement reaction time), a 2x8 full factorial design was tested with two materials (CPCA and CPCD) and 8 levels of incubation time: 15 min, 30 min, 1 h, 1.5 h, 2 h, 4 h, 8 h, and 24 h. An absorbable suture fiber was incorporated into CPC at 25 % volume fraction.The Gilmore needle method measured a hardening time of 15.8 min for CPCD, five-fold faster than 81.5 min for CPCA, at a powder:liquid ratio of 3:1. SEM revealed the formation of nano-sized rod-like hydroxyapatite crystals and platelet crystals in the cements. At 30 min, the flexural strength (mean sd; n = 5) was 0 MPa for CPCA (the paste did not set), (4.2 0.3) MPa for CPCD, and (10.7 2.4) MPa for CPCD-fiber specimens. The work-of-fracture (toughness) was increased by two orders of magnitude for the CPCD-fiber cement. The high early strength matched the reported strength for cancellous bone and sintered porous hydroxyapatite implants. The composite strength Sc was correlated to the matrix strength Sm: Sc = 2.16 Sm. In summary, substantial early strength and toughness were imparted to a moldable, self-hardening and resorbable hydroxyapatite. The new fast-setting and strong cement may help prevent catastrophic fracture or disintegration in moderate stress-bearing bone repairs.
Citation
Journal of Biomedical Materials Research Part A
Volume
75A
Issue
4

Keywords

absorbable fibers, bone repari, calcium phosphate cement, early strength, fast setting, hydroxyapatite

Citation

Burguera, E. , Xu, H. , Takagi, S. and Chow, L. (2005), High Early Strength Calcium Phosphate Bone Cement: Effects of Dicalcium Phosphate Dihydrate and Absorbable Fibers, Journal of Biomedical Materials Research Part A, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=852448 (Accessed March 3, 2024)
Created August 1, 2005, Updated February 19, 2017