scholarly journals Calcium phosphate crystal forms in human jaw bones of changed osteoporotic structure

2011 ◽  
Vol 58 (1) ◽  
pp. 23-28
Author(s):  
Srdjan Postic
Keyword(s):  
Calcium Phosphate ◽  
Calcium Phosphates ◽  
Chemical Compounds ◽  
Osteoporotic Bone ◽  
X Ray Diffraction ◽  
Crystal Forms ◽  
Jaw Bone ◽  
Jaw Bones ◽  
Human Cadavers ◽  
Hydrated Calcium

Introduction. Calcium phosphates are chemical compounds that can be found in various forms within nature, as well as in human jaws and bones. The aim of this study was to assess the structure of solid chemical compounds which form the structure of normal and osteoporotic jaw-bones. Materials and Methods. The jaw-bones taken from human cadavers were used in the study. Crystalographic forms of calcium phosphate, in the samples of human jaw-bone, were determined using X-ray diffraction technique. The experimental bone samples originated from osteoporotic jaw-bone of cadavers while control samples were taken from dentate jaw-bones of non-osteoporotic cadavers. Results. The results of this study showed that hydroxyapatite was the only phase determined in control non-osteoporotic bone samples. In experimental (osteoporotic) bone samples, the same phase was registered, as well as calcium monophosphate and hydrated calcium phosphate, registered as increments of values on ? axis. Conclusion. Hydroxyapatite was the only compound detected in normal bone while osteoporotic bone contained others crystallographic forms of calcium phosphates.

Carboxymethylchitosan/Calcium Phosphate Hybrid Materials Prepared by an Innovative Auto-Catalytic Co-Precipitation Method

2005 ◽  
Vol 284-286 ◽  
pp. 701-704 ◽  
Author(s):  
S.A. Costa ◽  
J. Miguel Oliveira ◽  
Isabel B. Leonor ◽  
Rui L. Reis
Keyword(s):  
Calcium Phosphate ◽  
Calcium Phosphates ◽  
Precipitation Method ◽  
Porous Scaffolds ◽  
X Ray Diffraction ◽  
Polymer Precipitation ◽  
Acid Bath ◽  
The Fourier Transform ◽  
Xrd Patterns ◽  
Co Precipitation

In this study, it is shown that it is possible to prepare carboxymethyl-chitosan/Ca-P hybrids using an innovative “auto-catalytic” co-precipitation method, namely by using an acid and an oxidant bath. The X-ray diffraction (XRD) patterns evidenced the formation of crystalline calcium-phosphate precipitates when using an acid bath, while amorphous ones were obtained for those produced in the oxidant bath. The Fourier Transform Infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM/EDS) studies revealed that the extent of the polymer precipitation and formation of calcium-phosphates is directly dependent on the pH and composition of the baths. Furthermore, by conducting bioactivity tests in a simulated body fluid (SBF) followed by the SEM/EDS analysis it was possible to detect the formation of an apatite layer with a cauliflower-like morphology on the surface of hybrids prepared by the acid bath, after 7 days of immersion. These results are quite promising because they can allow for the production of bioactive and biodegradable 3D porous scaffolds to be used in bone tissue engineering applications.

scholarly journals Powder bed selective laser process (sintering/melting) applied to tailored calcium phosphate-based powders

2021 ◽  
Author(s):  
Pedro Navarrete-Segado ◽  
Christine Frances ◽  
Mallorie Tourbin ◽  
Christophe Tenailleau ◽  
Benjamin Duployer ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Calcium Phosphate ◽  
Calcium Phosphates ◽  
Process Window ◽  
X Ray Diffraction ◽  
Powder Bed ◽  
Laser Process ◽  
Whole Process ◽  
Vibrational Spectroscopies ◽  
Complex Parts

This paper focuses on the tailoring of calcium phosphate powders for their use as powder bed selective laser process feedstock. Hydroxyapatite and chlorapatite were used as starting powders for the preparation of different blends through the addition of graphite as a laser absorptance additive. A methodical study was conducted to compare the processing windows of the blends containing different amounts of graphite through the laser patterning of circular samples. It was found that the addition of graphite increases the process window of the powder blends being the powder without additive non processable. Hydroxyapatite showed a clear phase transition (decreased when using higher volumetric energy density) into other calcium phosphate phases while chlorapatite was demonstrated to be thermally stable during the whole process (examined through X-ray diffraction and vibrational spectroscopies). In parallel, the study evaluating the powder blend composed of hydroxyapatite and graphite for the production of solid and complex parts was carried out although it required long printing times. The productivity of the process was improved by modification of printing parameters. Then, a series of solid samples were produced for the analysis of the microstructure and mechanical properties. High interconnected porosity was observed in the samples which could improve the bioactivity of the bioceramic scaffolds. A post-treatment of the parts increased their proportion in the hydroxyapatite phase and their mechanical properties. These results are expected to contribute to the application of powder bed selective laser processing of calcium phosphates powders toward bone tissue engineering.

scholarly journals Integrated 3D Information for Custom-Made Bone Grafts: Focus on Biphasic Calcium Phosphate Bone Substitute Biomaterials

2020 ◽  
Vol 17 (14) ◽  
pp. 4931
Author(s):  
Alessandra Giuliani ◽  
Maria Laura Gatto ◽  
Luigi Gobbi ◽  
Francesco Guido Mangano ◽  
Carlo Mangano
Keyword(s):  
Calcium Phosphate ◽  
Biphasic Calcium Phosphate ◽  
Alveolar Bone ◽  
Sintering Temperature ◽  
Calcium Phosphates ◽  
Compressive Loading ◽  
Peak Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Custom Made

Purpose: Several studies showed that the sintering temperature of 1250 °C could affect the formation of α-Ca3(PO4)2, which is responsible for the reduction of the hardness value of biphasic calcium phosphate biocomposites, but they did not evaluate the inference of the sintering time at peak temperature on transition of β-Ca3(PO4)2 to α-Ca3(PO4)2. This analysis explored, in an innovative way, inferences and correlations between volumetric microstructure, mechanical properties, sintering temperature, and time at peak temperature in order to find the best sintering conditions for biphasic calcium phosphate composites grafted in severe alveolar bone defects. Methods: Sintered biphasic calcium phosphates (30%-hydroxyapatite/70%-tricalcium phosphate) were tested by microCT imaging for the 3D morphometric analysis, by compressive loading to find their mechanical parameters, and by X-ray diffraction to quantify the phases via Rietveld refinement for different sintering temperatures and times at the peak temperature. Data were analysed in terms of statistical inference using Pearson’s correlation coefficients. Results: All the studied scaffolds closely mimicked the alveolar organization of the jawbone, independently on the sintering temperatures and times; however, mechanical testing revealed that the group with peak temperature, which lasted for 2 hours at 1250 °C, showed the highest strength both at the ultimate point and at fracture point. Conclusion: The good mechanical performances of the group with peak temperature, which lasted for 2 hours at 1250 °C, is most likely due to the absence of the α-Ca3(PO4)2 phase, as revealed by X-ray diffraction. However, we detected its presence after sintering at the same peak temperature for longer times, showing the time-dependence, combined with the temperature-dependence, of the β-Ca3(PO4)2 to α-Ca3(PO4)2 transition.

Synthesis and Characterization of Hydrated Calcium Phosphate: Precursors for Obtaining Biocements

2014 ◽  
Vol 798-799 ◽  
pp. 443-448
Author(s):  
Priscila Ferraz Franczak ◽  
Nelson Heriberto Almeida Camargo ◽  
Pricyla Corrêa ◽  
Enori Gemelli
Keyword(s):  
Calcium Phosphate ◽  
Biomedical Applications ◽  
Fine Particles ◽  
Calcium Phosphates ◽  
Synthesis Method ◽  
Synthesis Process ◽  
Promising Alternative ◽  
Hydrated Calcium ◽  
Reactive Method

Calcium phosphates biocements are biomaterials that present crystallographic and mineralogical characteristics similar to human skeletal structure. This has led to the development of new calcium phosphates biomaterials for biomedical applications, especially biomaterials for repairing defects and bone reconstruction. Calcium phosphates biocements are a promising alternative in biomedical applications, for they are easy to mold, they have good wettability, hydration and hardening capacity during its application in biological means. This work aimed at the synthesis of hydrated calcium phosphates powder, through a simple reactive method, which will be the basis for the production of calcium phosphate biocimentos with self-setting reaction. Three calcium phosphates compositions were produced via CaCO3/phosphoric acid reactive method in the ratios Ca/P = 1,5; 1,6 e 1,67 molar. The presented results are associated to hydrated powder morphology and synthesis process control. Scanning Electron Microscopy (SEM) helped with the morphological characterization of the powders, the laser analysis method was used for determining particle size and the Fourier Transformed Infrared Spectroscopy (FTIR) gave support to the identification of H2O e PO43-grouping vibrational bands. The work showed that for the different powder compositions the hydrated calcium phosphate phase is formed by clustered fine particles. This demonstrated that the chosen synthesis method permits the obtention of hydrated calcium phosphates, precursors for later biocement production.

Characterization of Calcium Phosphate with an Anodic TiO2 Nanotube Layer on Titanium Screw for Biomedical Application

2014 ◽  
Vol 852 ◽  
pp. 251-255
Author(s):  
Ya Jing Yan ◽  
Yong Huang ◽  
Qiong Qiong Ding ◽  
Xiao Feng Pang
Keyword(s):  
Calcium Phosphate ◽  
Biomedical Application ◽  
Calcium Phosphates ◽  
Alkaline Treatment ◽  
Calcium Phosphate Coating ◽  
X Ray Diffraction ◽  
Titanium Screw ◽  
Phosphate Coatings ◽  
Titanium Screws ◽  
Calcium Phosphate Coatings

The present paper reports a novel solution to develop a calcium phosphates (CaPs) coating with an anodic nanotubular TiO2layer on titanium screw by electrochemical disposition (ECD). The elemental composition of coatings was examined by energy dispersive spectroscopy (EDS), the surface mopholoy was characterized with scanning electron microscopy (SEM), and the functional groups and crystalline phase were analyzed using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Furthermore, the bioactivity was tested by immersion in simulated body fluid (SBF) for 7 days. The results showed that a nanotubular TiO2layer was established which has about 100 mm diameter and the calcium phosphate coatings have higher bioactivity and porosity compared with uncoated titanium screws, which make the coating more conductive to cell adhesion. Using alkaline treatment, the calcium phosphate coating could transform into hydroxyapatite (HAp), making the coating closer to the biological complement. This provides a valuable tool for biomedical applications.

Effects of citrate and NaCl on size, morphology, crystallinity and microstructure of calcium phosphates obtained from aqueous solutions at acidic or near-neutral pH

2012 ◽  
Vol 79 (2) ◽  
pp. 238-248 ◽  
Author(s):  
Omar Mekmene ◽  
Thierry Rouillon ◽  
Sophie Quillard ◽  
Paul Pilet ◽  
Jean-Michel Bouler ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Calcium Phosphates ◽  
Octacalcium Phosphate ◽  
Inhibitory Effect ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
Phosphate Dihydrate ◽  
Constant Ph ◽  
Starting Solutions ◽  
Calcium Phosphate Precipitation

Precipitation of calcium phosphates occurs in dairy products and depending on pH and ionic environment, several salts with different crystallinity can form. The present study aimed to investigate the effects of NaCl and citrate on the characteristics of precipitates obtained from model solutions of calcium phosphate at pH 6·70 maintained constant or left to drift. The ion speciation calculations showed that all the starting solutions were supersaturated with respect to dicalcium phosphate dihydrate (DCPD), octacalcium phosphate (OCP) and hydroxyapatite (HAP) in the order HAP>OCP>DCPD. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analyses of the precipitates showed that DCPD was formed at drifting pH (acidic final pH) whereas poor crystallised calcium deficient apatite was mainly formed at constant pH (6·70). Laser light scattering measurements and electron microscopy observations showed that citrate had a pronounced inhibitory effect on the crystallisation of calcium phosphates both at drifting and constant pH. This resulted in the decrease of the particle sizes and the modification of the morphology and the microstructure of the precipitates. The inhibitory effect of citrate mainly acted by the adsorption of the citrate molecules onto the surfaces of newly formed nuclei of calcium phosphate, thereby changing the morphology of the growing particles. These findings are relevant for the understanding of calcium phosphate precipitation from dairy byproducts that contain large amounts of NaCl and citrate.

Antimicrobiologic Property Hydrated Amorphous Calcium Phosphates Containing Silver

2005 ◽  
Vol 284-286 ◽  
pp. 439-444 ◽  
Author(s):  
O.J. Aimanova ◽  
Racquel Z. LeGeros ◽  
V.A. Sinyayev
Keyword(s):  
Thermal Analysis ◽  
Nuclear Magnetic Resonance ◽  
Differential Thermal Analysis ◽  
Infrared Spectroscopy ◽  
Calcium Phosphate ◽  
Calcium Phosphates ◽  
Antimicrobial Effect ◽  
X Ray Diffraction ◽  
X Ray ◽  
E Coli

The purpose of this study was to determine the microbiologic effect silver (Ag) when incorporated in amorphous calcium phosphate (ACP) prepared from solutions containing calcium, phosphate and pyrophosphate ions. The preparations were obtained from solutions with phosphate/pyrophosphate ratio, P/P2 = 7/3, and characterized as ACP using X-ray diffraction, infrared spectroscopy, nuclear magnetic resonance and differential thermal analysis. The microbes tested were cultures of E. Coli, St. aureus, Ps aerogunosa, C. diphteroides and C. albicans in media alone (control), with ACP without Ag and with ACP containing different Ag concentrations. Results demonstrated the following: (1) Ag in ACP inhibited the growth of microorganisms in all five cultures, with ACP containing 3-6% Ag giving the greatest antimicrobial effect; (2) sensitivity to the antimicrobial action of Ag differed among the bacteria.

Comparison of Calcium CPP, HAp and TeCP Phosphates, Obtained by Direct Reaction

2008 ◽  
Vol 396-398 ◽  
pp. 557-560 ◽  
Author(s):  
Sara Verusca de Oliveira ◽  
Marcus Vinícius Lia Fook ◽  
Elaine Patrícia Araújo ◽  
A.C.B.M. Fook ◽  
R.S.C. Lima ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Data Base ◽  
Calcium Phosphates ◽  
Direct Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Biological Environment

In bioscience, there are several apatites constituteds by differents compositions. In the biological environment, apatites are found in bones and teeth of vertebrates with Ca/P ration from 2.0 to 0.5. It is not easy to determine the exact proportion of Ca2 + and PO43- in solution in the preparation of the process. In this study, apatites with Ca/P ration 1.0, 1.67 and 2.0 were prepared by direct reaction in an solution of H3PO4 in a suspension of Ca(OH)2, of same molarity, evalueting the crystallinity of CPP, Hap e TeCP with 1 mol/l, 3 mol/l and 5 mol/l. The samples characterized by X-ray diffraction (XRD) were compared with the standard of reference of the data base JCPDS. The composition of calcium phosphate for the differents molarity studied, resulted in a combination of phases with the exception of hydroxyapatite Ca/P ration 1.67 at concentrations 1 mol/l and 3 mol/l. But the diffractograms revealed that the increased molarity provided a decrease of some peaks of reflection of calcium phosphates with Ca/P ration 1.67. However, for the Ca/P ration 1.0 increasing the concentration, showed an increase of crystallinity of calcium phosphates. The FTIR confirmed the presence of phosphates in the spectrums around 1045 cm-1. The calcium phosphates obtained through direct reaction showed Ca/P ration is related with the technique employed, consolidating it in the preparation of these bioceramics.

scholarly journals Comparison of the Effect of the Amino Acids on Spontaneous Formation and Transformation of Calcium Phosphates

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 792
Author(s):  
Ina Erceg ◽  
Nadica Maltar-Strmečki ◽  
Darija Domazet Jurašin ◽  
Vida Strasser ◽  
Marija Ćurlin ◽  
...  
Keyword(s):  
Amino Acids ◽  
Calcium Phosphate ◽  
Calcium Phosphates ◽  
Functional Materials ◽  
Precipitation Process ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Transmission Electron ◽  
Electron Paramagnetic Spectroscopy

Understanding the effect that specific amino acids (AA) exert on calcium phosphate (CaPs) formation is proposed as a way of providing deeper insight into CaPs’ biomineralization and enabling the design of tailored-made additives for the synthesis of functional materials. Despite a number of investigations, the role of specific AA is still unclear, mostly because markedly different experimental conditions have been employed in different studies. The aim of this paper was to compare the influence of different classes of amino acids, charged (aspartic acid, Asp and lysine, Lys), polar (asparagine, Asn and serine, Ser) and non-polar (phenylalanine, Phe) on CaPs formation and transformation in conditions similar to physiological conditions. The precipitation process was followed potentiometrically, while Fourier transform infrared spectroscopy, powder X-ray diffraction, electron paramagnetic spectroscopy (EPR), scanning and transmission electron microscopy were used for the characterization of precipitates. Except for Phe, all investigated AAs inhibited amorphous calcium phosphate (ACP) transformation, with Ser being the most efficient inhibitor. In all systems, ACP transformed in calcium-deficient hydroxyapatite (CaDHA). However, the size of crystalline domains was affected, as well as CaDHA morphology. In EPR spectra, the contribution of different radical species with different proportions in diverse surroundings, depending on the type of AA present, was observed. The obtained results are of interest for the preparation of functionalized CaPs’, as well as for the understanding of their formation in vivo.

Effect of Calcination Conditions on Phase Formation of Calcium Phosphates Ceramics Synthesized by Homogeneous Precipitation

2006 ◽  
Vol 530-531 ◽  
pp. 612-617 ◽  
Author(s):  
Dolores Ribeiro Ricci Lazar ◽  
Sandra Maria Cunha ◽  
Valter Ussui ◽  
E. Fancio ◽  
Nelson Batista de Lima ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Calcium Phosphates ◽  
Biological Response ◽  
Phase Evolution ◽  
Atomic Ratio ◽  
Biochemical Properties ◽  
X Ray Diffraction ◽  
Calcium Phosphate Ceramic ◽  
Ammonium Hydrogen ◽  
Ammonium Hydrogen Phosphate

Phase composition of calcium phosphate ceramics is a characteristic directly related to the biological response of implants due to the differences in mechanical and biochemical properties of these compounds. In this sense, it was evaluated in this work the crystalline phase evolution of calcium phosphates samples synthesized by wet precipitation route. Fixing Ca/P atomic ratio as 1.67, precipitation was carried out from heated aqueous solutions of calcium chloride and ammonium hydrogen phosphate, in ammonium medium (pH = 10). After washing and drying steps, calcination was performed at 600 to 1100 oC for 1 and 3 hours. Milled and pressed powders were sintered at 1250 oC for 1 hour. Samples were characterized by X-ray diffraction, chemical analysis, scanning electron microscopy, gaseous adsorption, laser diffraction and apparent density measurements. Results indicate the formation of a biphasic calcium phosphate ceramic containing hydroxyapatite as a major phase and β - tricalcium phosphate, the later obtained by heat treatment above 600 oC.

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