Fabrication of novel bioresorbable .BETA.-tricalcium phosphate cement on the basis of chelate-setting mechanism of inositol phosphate and its evaluation

Abstract

We have developed novel bioresorbable ¢-tricalcium phosphate (¢-TCP) cements on the basis of chelate-setting mechanism of inositol phosphate (IP6). The starting cement powders (IP6/¢-TCP powders) were prepared by surface-modifying ¢-TCP particles with IP6. The cement specimen was fabricated by mixing the IP6/¢-TCP powder in pure water at desired powder/ liquid ratios, and examined the effects of powder properties of the IP6/¢-TCP powder on the mechanical strength (compressive strength) of the cement specimens. We focused on the crystalline phase, particle size, specific surface area (SSA), and crystallite size among powder properties. The crystalline phase of resulting cement specimen was ¢-TCP single phase or mixture of ¢-TCP and calcium-deficient apatite (CDAp). The ¢-TCP cement with compressive strength of 13 MPa was fabricated from the finelyground ¢-TCP powders prepared by ball-milling commercially-available ¢-TCP powder for 4 h using zirconia beads with 10 mm in diameter. Meanwhile, the ¢-TCP/CDAp biphasic cement had maximum compressive strength of about 23 MPa among the examined cement specimens, it was fabricated from the ball-milled commercially-available ¢-TCP powder for 3 h using zirconia beads with 10 mm in diameter, and then for 3 h using zirconia beads with 2 mm in diameter. In order to make the determining factors of the compressive strength clear, we examined the relationship between powder properties (particle size, SSA and crystallite size) and compressive strength. The strength of the IP6/¢-TCP cement was not dependent on the particle size of the IP6/¢-TCP powder; meanwhile, the strength was enhanced with increasing SSA and decreasing crystallite size. Thus, the IP6/¢-TCP powder with higher SSA and smaller crystallite size may be useful in the fabrication of chelate-setting ¢-TCP cement with enhanced mechanical properties.

Fabrication of chelate-setting cement from hydroxyapatite powder prepared by simultaneously grinding and surface-modifying with sodium inositol hexaphosphate and their material properties

“…21) Therefore, it is expected that the ¦-potential of HAp particles surface-modified with IP6-Na could also become negative with an increase in the amount of adsorbed IP6. The resulting negative surface charge could therefore change the electrostatic interaction between HAp particles.…”

EFFECT OF THE ADDITION OF VARIOUS POLYSACCHARIDES ON THE MATERIAL PROPERTIES AND CYTOTOXICITY OF CHELATE-SETTING ^|^beta;-TRICALCIUM PHOSPHATE CEMENT

“…Hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ; HAp) and β-tricalcium phosphate (β-Ca 3 (PO 4 ) 2 ; β-TCP) have been used as bioceramics for bone grafting. They are known to be biocompatible and osteoconductive materials.…”

“…One of the present authors and his coworkers have developed a novel CPC using inositol hexaphosphate (C 6 H 6 (OPO 3 H 2 ) 6 ; IP6) as a chelating agent 3,4 . IP6 is found in wheat, rice, corn, and soybean 5 and has a strong chelating capability to calcium ion, for example, ethylenediaminetetraacetic acid (EDTA).…”

“…We have also developed a novel biodegradable cement consisting of a β-TCP single phase based on our previous finding on the fabrication of HAp cement due to chelate-setting mechanism using IP6 3,4,6 . The β-TCP cement could be simply fabricated by mixing starting β-TCP powder surface-modified with IP6 and pure water 6 .…”

Preparation of injectable hydroxyapatite/collagen paste using sodium alginate and influence of additives

“…A biodegradable chelate-setting ¢-tricalcium phosphate (¢-TCP) cement using inositol hexaphosphate was prepared and was absorbed in the living body. 5) This cement showed good properties but still needs much improvement on biodegradability. Recently, clinical trial data of the hydroxyapatite/collagen nanocomposite (HAp/ Col) having similar chemical composition and nanostructure to bone 6)9) conclude that the HAp/Col shows remarkable curative efficacy rate in comparison to ¢-TCP artificial bone, Osferionμ, which is recognized by surgeons as very efficient artificial bone.…”