Formation of Macropores in Calcium Phosphate Cements Through the Use of Mannitol Crystals

Published

January 1, 2001

Author(s)

Milenko Markovic, Shozo Takagi, Laurence C. Chow

Abstract

Mannitol crystals with sizes ranging from {nearly equal to} 100 m to {nearly equal to} 400 m were mixed with calcium phosphate cement (CPC) powders that contained equimolar amounts of tetracalcium phosphate and dicalcium phosphate anhydrous. CPC-mannitol mixtures with mass fractions of (a) 0 % and (b) 10 % mannitol were mixed with cement liquid (1 mol/L Na₂HPO₄ solution) at powder-to-liquid ratio (P/L) of 4 g/mL. The hardening times for the two mannitol-containing cements were (a) 5.3 0.3 and (b) 5.5 0.5 (n = 5). The cement pastes were packed into sample molds with an applied pressure of {nearly equal to} 2 MPa. Samples were removed from molds 4 h later and placed in water for 20 h causing complete dissolution of the mannitol and formation of macropores in the shapes of the mannitol crystals. Properties of the 24-h cement samples are as follows: Densities of dried samples were (a) 2.05 0.03 g/cm³ and (b) 1.83 0.04 g/cm³ and (b) (1.83 0.04) g/cm³ (n=8). Macroporosities were (a) 0% and (b) (10.9 1.17) % (n = 8), and microporosities were (a) (34.3 1.0) % and (b) (30.6 0.6)% (n = 8). Diametral tensile strengths (DTS) were (a) (11.8 1.5) Mpa and (b) (7.6 0.9) Mpa (n - 8). Additional CPC-mannitol samples were prepared with P/L = 10 g/mL under a pressure of {nearly equal to} 660 MPA. The DTS of these samples were (a') (20.6 1.5) Mpa and (b') (13.8 1.2) Mpa (n=3).

Proceedings Title

Proceedings of the 13th International Symposium on Ceramics in Medicine; Bioceramics 13

Conference Dates

November 22-26, 2000

Conference Location

Bologna, IT

Conference Title

International Symposium on Ceramic Materials and Components for Engines

Pub Type

Conferences

Keywords

calcium phosphate cement, hardening time, macropores, mannitol, porosity, strength

Citation

Markovic, M. , Takagi, S. and Chow, L. (2001), Formation of Macropores in Calcium Phosphate Cements Through the Use of Mannitol Crystals, Proceedings of the 13th International Symposium on Ceramics in Medicine; Bioceramics 13, Bologna, IT (Accessed May 7, 2024)