Properties of injectable apatite-forming premixed cements

Yashushi Shimada, Laurence C. Chow, Shozo Takagi, Junji Tagami

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Previous studies reported premixed calcium phosphate cements (CPCs) that were stable in the package and form hydroxyapatite (HA) as the product after exposure to an aqueous environment. These cements had setting times of greater than 60 min, which are too long to be useful for some clinical applications. The present study investigated properties of fast-setting HA-forming premixed CPCs that initially consisted of two separate premixed pastes: (1) finely ground (1.0 μm in median size) dicalcium phosphate anhydrous (DCPA) mixed with an aqueous NaH 2PO 4 solution, 1.5 mol/L or 3.0 mol/L in concentration, and (2) tetracalcium phosphate consisting of combinations of particles of two different size distributions, 5 μm (TTCP5) and 17 μm (TTCP17) in median size, mixed with glycerin. Equal volume of Pastes 1 and 2 were injected with the use of atwobarrel syringe fitted with a static mixer into sample molds. The molar Ca/P ratio of combined paste was approximately 1.5. Cements were characterized in terms of setting time (Gilmore needle), diametral tensile strength (DTS), and phase composition (powder x-ray diffraction, XRD). Setting times were found to range from (4.3 ± 0.6 to 68 ± 3) min (mean ± sd; n = 3), and 1-d and 7-d DTS values were from (0.89 ± 0.08 to 2.44 ± 0.16) MPa (mean ± sd; n = 5. Both the NaH 2PO 4 concentration and TTCP particle size distribution had significant (p μ 0.01) effects on setting time and DTS. Powder XRD analysis showed that low crystallinity HA and unreacted DCPA were present in the 1-day specimens, and the extent of HA formation increased with increasing amount of TTCP5 in the TTCP paste. Conclusion: Injectable HA-forming premixed CPCs with setting times from 4 to 70 min can be prepared by using DCPA and TTCP as the ingredients. Compared to the conventional powder liquid cements, these premixed CPCs have the advantages of being easy to use and having a range of hardening times.

Original languageEnglish
Pages (from-to)233-241
Number of pages9
JournalJournal of Research of the National Institute of Standards and Technology
Volume115
Issue number4
DOIs
Publication statusPublished - 2010
Externally publishedYes

Keywords

  • Bone graft
  • Crystallinity
  • Dicalcium phosphate anhydrous
  • Dual-paste premixed calcium phosphate cement
  • Tetracalcium phosphate

ASJC Scopus subject areas

  • Engineering(all)

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