Stoichiometric Hydroxyapatite (Ca10(PO)6(OH)2, HAP) foams, have been produced. The porous parts were prepared from a calcined HAP powder and egg white as a bio and nontoxic pore promoter. The colloidal slurry was prepared, poured into cylindrical molds, dried, unmolded, and sintered at 1200 °C. The effects of the concentration of the solid loading, of the dispersing agent, and the foaming agent on the ceramic preparation were examined. X-Ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) were used to evaluate the composition and the structure of the sintered HAP ceramics. Scanning Electron Microscopy (SEM) was used for microstructural analysis. The XRD analysis of the porous parts, prepared under optimized conditions, showed the presence of crystalized HAP (JCPDS 9-432) as a single phase. SEM images showed existence of open and interconnected micro and macro-pores in the ceramics. The use of the egg white protein as pore former provides a total porosity of 86 vol-% and a foam-structure that allows to a micro-porous wall.
Numerous clinical studies have demonstrated the influence of the size, number and shape of pores into calcium phosphate ceramics on the process of bone regeneration.The main objective of this study is to determine the microstructure, the morphological characteristics and classes of pores of the prepared hydroxyapatite bioceramic using an adaptive method based on the mathematical morphological operations. The study was carried out using X-ray microtomography and Scanning Electron Microscopy images. The conventional method of openings alone presents limitation of calculation and not sufficient to achieve our objective. The proposed method allowed us to extract local characteristics and calculate precisely the morphological parameters while preserving the original volume of pores. The number and classes of pores with their size, surface of contact of the component and the number of connected pores to each pore were calculated. The method is subjectively and quantitatively evaluated using different computed phantoms and its efficiency is clearly demonstrated through the different reports and measurements generated. The proposed method can have interesting applications in the characterization of porous materials used in the medical field or in other sectors.
In this work, we report the physico-chemical properties and antibacterial activity of apatite/chitosan composite cements. The biocomposite was prepared by reaction between dihydrated dicalcium phosphate and calcium hydroxide in the presence of chitosan. The characterization of cement was carried out by Infrared Spectroscopy, X-ray diffraction, Transmission Electron Microscopy and X-ray Scanner with computational image processing. The results show that the setting of the paste is due to the formation of a hydrated tri-calcium phosphate that evolves into a hard calcium-apatite. In the presence of chitosan, the fastness of setting time is attributed to the precipitation of chitosan that strengthens the cohesion between grains. The formed complex evolves into hard Apatite-chitosan composite. In an induced bone defect, the hard composite shows radiopaque homogenous microstructure and intimate contact bone/implant. The antibacterial tests of hard cements show a significant reduction in Staphylococci bacterial growth on the surface of composite grains. This reduction is highly dependent on the type of bacteria, and the percentage of the added antibacterial agent. Bio-composite cement shows total inhibition of Staphylococci aureus and low resistance to Staphylococci epidermidis. The apatite/chitosan composite prepared by the way of cements can have interesting applications as bone substitute material.
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