Long-term evaluation of the degradation behavior of three apatite …
Therefore, the long-term degradation behavior of two types of α-tricalcium phosphate-based, apatite-forming CPCs was compared to a commercially available apatite-forming cement, that is HydroSet™ . Carboxyl methylcellulose (CMC) was used as cohesion promotor to improve handling properties of the two experimental cements, whereas poly …
CHAPTER 1: Biological Apatites in Bone and Teeth
Most biominerals are inorganic/organic composite materials. 1 This is also the case for the bones and teeth of all vertebrates, which are formed by the combination of an inorganic calcium phosphate phase and an organic matrix 2 ().The inorganic component is a nanocrystalline solid with apatite structure and the chemical …
Transformation of amorphous calcium phosphate to bone …
Mineralisation of calcium phosphates in bone has been proposed to proceed via an initial amorphous precursor phase which transforms into nanocrystalline, …
Apatite
The main difference between the apatite cements consisting of α-TCP and TTCP–DCPA is that the former consist of single calcium phosphate powder whereas the latter consist of two calcium phosphate powders. The Ca/P ratio of TTCP is 2.0 and is higher than that of HAp, which has a Ca/P ratio of 1.67.
A review on the thermal stability of calcium apatites
The multifunctionality of calcium apatite is attributed to a large capability for elemental substitution, the active surface and a range in crystal perfection (low to high crystallinity). ... De Blieck-Hogervorst J. Calcium phosphate and hydroxylapatite ceramics. Plasma-sprayed coatings of calcium phosphate. In: Yamamuro T, Hench LL, Wilson J ...
Structure and formation of amorphous calcium phosphate …
Abstract. We provide a critical review of the chemical composition and structure of synthetic and biogenic (bone/dentin mineral) nanocrystalline hydroxy …
Apatite stones in dogs – Dr. Nelson's Veterinary Blog
Apatite or calcium phosphorous stones are the least common type of stone I see in practice. These rare stones form from the same risk factors responsible for calcium oxalate stones. These include increased amounts of calcium and/or phosphate in the urine. The one big difference is pH. While calcium oxalate stones precipitate out of …
Apatitic calcium phosphates: Synthesis
Ca-HA appeared as the principal apatite, while some amounts of octacalcium bis(hydrogenphosphate) tetrakis(phosphate) pentahydrate (OCP, Ca 8 (HPO 4) 2 (PO …
KIDNEY STONE TYPES | Kidney Stone Program
Here are the names of the crystals that make the stones: CAOX, Calcium Oxalate; CAP, Calcium phosphate; UA, Uric Acid; Cystine; Struvite. The wedges on my …
Hydroxylapatite | Bone Structure, Calcium Phosphate
hydroxylapatite, phosphate mineral, calcium hydroxide phosphate [Ca 5 (PO 4) 3 OH], that forms glassy, often green crystals and masses. It is seldom pure in nature but often occurs mixed with fluorapatite, in which fluorine substitutes for the hydroxyl (OH) group in the molecule. This mixture, called a solid-solution series, is a continuous ...
CALCIUM PHOSPHATE STONES: Causes and Prevention
A minority, more women than men, form calcium phosphate (CaP) stones. Idiopathic calcium phosphate stone formers are dual. Most have hydroxyapatite (HA, like bone mineral) as their stone calcium phosphate. Some have brushite (Br, calcium …
High carbonate level of apatite in kidney stones underlines …
In 51 patients in which the carbonate content of apatite could be measured, carbonate in the apatite was weakly predictive of positive stone culture with an optimal cutoff value of 13.5% carbonate (sensitivity 0.61, specificity 0.80). In positive cultures of stones (all mineral types combined), organisms that characteristically produce urease ...
Place des substituts de l'os dans les pertes de substances …
Leur forme et taille correspondent à ceux de l'apatite de l'os humain. ... L'évolution radiologique a montré pour le phosphate de calcium une résorption progressive au fil du temps allant selon les cas de 100 % à 12 mois à moins de 25 % à 24 mois. En dehors de 5 cas l'utilisation du substitut osseux a évité un prélèvement ...
Influence of apatite seeds on the synthesis of calcium phosphate cement
A number of other combinations between different calcium phosphate salts have been reported. Boudeville et al. [17] used monocalcium phosphate monohydrate (MCPM) and calcium oxide in water to form apatite in 24 h. However, when phosphate buffer was employed as cement liquid, the reaction was incomplete, only about 70% …
The role of collagen in bone apatite formation in the …
Apatite crystals are found within an amorphous calcium phosphate bed, which can still be seen infiltrating into the fibril through the a-band (inset 1, black arrow). Insets 2–5 show crystals ...
Calcium phosphate apatites with variable Ca/P atomic
Single phased apatitic calcium phosphate powders Ca 10−x (PO 4) 6−x (HPO 4) x (OH) 2−x with Ca/P molar ratio ranging from 1.5 to 1.667 (0⩽x⩽1) were synthesised using wet method. Outside this compositional range the powders were biphasic mixtures composed of a calcium phosphate apatite and CaHPO 4 (Ca/P<1.5) or …
Bone Apatite
All calcium phosphate (CaP) apatites have the same formula Ca 5 (PO 4) 3 X where X can be for example an OH − ion (hydroxyapatite) or a CO 2− 3 ion (carbonated apatite). The basic CaP apatite structure is hexagonal with space group P6 3 /m and approximate lattice parameters a=9.4 and c=6.9 Å with two formula units per cell. The apatite ...
Structure and formation of amorphous calcium phosphate …
As illustrated in Fig. 1 a, the archetypal preparation route of apatite and its precursor ACP is direct precipitation by mixing two solutions that comprise Ca and phosphate species, respectively, typically in the 5–20 mM range with respect to each of Ca 2 + and PO 4 3 −, and sometimes arranging [Ca]/[PO 4] ≈ 1.67 to match that of the …
Etude de la precipitation des phosphates de calcium
L'hydroxyapatite de formule Ca10(PO4)6(OH)2 a été élaborée à 100°C et à pH 8 par précipitation à partir d'une solution de calcium, obtenue à partir du carbonate de calcium, et d'une ...
Roles of Fluoride on Octacalcium Phosphate and Apatite
The calcium phosphate composite octacalcium phosphate / calcite was obtained at pH 5–7 from the CaCO 3 /Ca(H 2 PO 4 ) 2 aqueous suspension in a galvanostatic mode at a current density of 20 mA ...
The role of intracellular calcium phosphate in osteoblast
However, despite their requisite function in building bone and decades of observations describing intracellular calcium phosphate, the precise role osteoblasts play in mediating bone apatite formation remains largely unknown. To better understand the relationship between intracellular and extracellular mineralization, we combined a …
Structure of vanadate in calcium phosphate and vanadate apatite …
e Departamento de Química Orgânica, Instituto de Química, Uniersidade Federal do Rio de Janeiro, Departamento de Ciências Naturais, Uniersidade do Rio Janeiro, Brazil Abstract Polycrystalline solid solutions of phosphate and vanadate calcium apatites were synthesized and studied by XRD, XPS, 31 P and 51 V NMR, FTIR and …
Carbonate substitution significantly affects the structure and
1. Introduction. Bone mineral is often described as a kind of hydroxlyapatite (HAP), a hydroxyl-containing calcium phosphate with the formula Ca 10 (PO 4) 6 (OH) 2.However, research has indicated that bone mineral is a highly-substituted calcium-depleted apatite [1], [2], [3].Biogenic apatite is incredibly accommodative in terms of …
Calcium phosphate apatites with variable Ca/P atomic ratio I.
The synthesis of single phased calcium phosphate apatites with variable Ca/P atomic ratio within the range 1.50–1.667 can be performed by the precipitation …
Fourier Transform Infrared Spectroscopy of Developing Bone …
The amorphous calcium phosphate (ACP) component of developing bone may be an apatite precursor when subjected to ex vivo crystallization conditions. The tips of the developing zebrafish caudal fin bones were analyzed and subjected to 24h in a buffer that favors the crystallization of ACP into apatite.
(PDF) Synthèse du phosphate tricalcique apatitique et
L'objectif de ce travail est la synthèse du phosphate. tricalcique par la méthode de la double décomposition, sa. céramisation en β -TCP et l'étude de l'effet de la. température de ...
Phase Transformations in Calcium Phosphate Crystallization
Abstract. Calcium phosphates are widespread in geochemistry, in biomineralization, and as biomaterials, and thus they have solicited great interest among researchers. In this chapter, prenucleation phenomena, amorphous phases, and crystallization processes from amorphous precursors are discussed for the calcium …
Calcium phosphates for biomedical applications
La historia de los fosfatos de calcio en el campo de la medicina comienza en 1769, cuando se descubre la primera evidencia de su existencia en el tejido óseo. ... Apatite was the first calcium phosphate recognized as mineral specie. It was in 1786 when Abraham Gottlob, well-known as the father of German geology, discovered this …
Transformation of amorphous calcium phosphate to bone-like apatite
Herein, we demonstrate a detailed transformation mechanism of amorphous calcium phosphate spherical particles to apatite platelet-like crystals, within the confined nanodomains of a bone-inspired nanocomposite. The transformation is initiated under the presence of humidity, where nanocrystalline areas are formed and crystallisation …
The role of intracellular calcium phosphate in osteoblast
We identified calcium phosphate both within osteoblast mitochondrial granules and intracellular vesicles that transported material to the ECM. Moreover, we …
The role of intracellular calcium phosphate in osteoblast
To investigate the relationship between intracellular calcium phosphate accumulations and extracellular bone apatite formation, we cultured mouse calvarial osteoblasts and marrow stromal cells (MSC) in osteogenic medium according to standard in vitro methods for bone-like nodule formation ().We have previously demonstrated by …
Synthesis of β-tricalcium phosphate
Method of synthesis of phosphate tricalcium (TCP) per neutralisation from CaCO 3 and H 3 PO 4. We also propose to prepare tricalcium phosphate apatite from low-cost reagents available such as calcium carbonate, CaCO 3 as a calcium source and phosphoric acid H 3 PO 4 as a phosphate source using the method established by …
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