Structural and mechanical characterization of Calcium Phosphate Cements (CTCs) with different powder-liquid ratios

Abstract

Calcium phosphate cements (CPCs) are encouraging osteoconductive bone substitutes for bone grafting. In this study, new bone cements were prepared by mixing powders of tetra calcium phosphate (TTCP), dicalcium phosphate dihydrate (DCPD) andcalciumsulfatedehydrate(CSD)topolymericsolutionincludingCMCandgelatin. Samples with different powder-to-liquid ratio (62.5, 65, 67.5, and 70%) were fabricated and characterized. Scanning Electron Microscopy (SEM), mechanical testing, Fourier Transform Infrared Spectroscopy (FTIR), Thermo-gravimetric Analysis (TGA), and X-raydiffraction(XRD)Analysiswereperformedtocharacterizemechanicalandstructural properties of synthesized composites. FTIR results confirmed the electrostatic interaction between COO− groups in carboxymethyl cellulose (CMC) and Ca2+ ions released from CPCs. Hydroxyapatite (HA) formation was observed and assessed via XRD and SEM analysis on the samples incubated in phosphate buffer saline (PBS) solution for 28 days. Furthermore, the compressive strength values of composites were calculated as 1.63±0.046, 1.53±0.053, 0.91±0.015 and 1.28±0.072 MPa for P62.5, P65, P67.5, and P70, respectively. The overall results show that composite with 65% powder ratio may be appropriate for applications in the field of bone tissue engineering considering that it has the most proper mixture of the powder and liquid phase, high HA formation and sufficient mechanical properties for bone regeneration.|Keywords : Calcium phosphate, carboxymethyl cellulose, composite, mechanic, bone.