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Баринов, С. М.; Tumanov, S. G.; Фадеева, И. В.; Bibikov, V. Yu.

doi:10.1023/a:1025041817017

Cited by 27 publications

(10 citation statements)

References 7 publications

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“…Among these latter species, Fluorine is known to delay the caries' processes [7], improve the bonds between the bones and the implant [8][9][10], and strengthen the bone structure 2 3 CO  [11]. Furthermore, this element decreases the solubility and enhances the thermal stability of the hydroxyapatite [12]; therefore, when fluorine is incorporated into bone mineral, its resorption is reduced. On the other hand, Magnesium has a beneficial effect on the mineralization processes [13,14], osteoporosis [15] and might play a role on the osteoblastic and osteoclastic activities [16,17].…”

Section: Introductionmentioning

confidence: 99%

Sintering and Mechanical Properties of Magnesium and Fluorine Co-Substituted Hydroxyapatites

Nsar¹,

Hassine²,

Bouzouita³

2013

JBNB

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Biological apatites contain several elements as traces. In this work, magnesium and fluorine co-substituted hydroxyapatites with the general formula Ca 9 Mg(PO 4 ) 6 (OH) 2-y F y , where y = 0, 0.5, 1, 1.5 and 2 were synthesized by the hydrothermal method. After calcination at 500˚C, the samples were pressureless sintered between 950˚C and 1250˚C. The substitution of F − for OH − had a strong influence on the densification behavior and mechanical properties of the materials. Below 1200˚C, the density steeply decreased for y = 0.5 sample. XRD analysis revealed that compared to hydroxylfluorapatite containing no magnesium, the substituted hydroxyfluorapatites decomposed, and the nature of the decomposition products is tightly dependent on the fluorine content. The hardness, elastic modulus and fracture toughness of these materials were investigated by Vickers's hardness testing. The highest values were 622 ± 4 GPa, 181 ± 1 GPa and 1.85 ± 0.06 MPa·m 1/2 , respectively.

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Section: Introductionmentioning

confidence: 99%

Sintering and Mechanical Properties of Magnesium and Fluorine Co-Substituted Hydroxyapatites

Nsar¹,

Hassine²,

Bouzouita³

2013

JBNB

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“…Environmentally assisted crack growth refers to an enhancement in crack growth that takes place due to a stress-enhanced chemical reaction at the highly strained region near a crack tip [11,[109][110][111][112]. In particular, when exposed to water, HA exhibits higher susceptibility to slow crack growth than in air as indicated by n values of 10 ± 4, 11.3, 11 measured in water, which are lower than the n values measured in ambient air (n = 22.5 ± 2, 19.8, 23) [17,20,21].…”

Section: Perturbation From Lateral Cracksmentioning

confidence: 94%

“…Both indirect static/dynamic fatigue tests [16][17][18][19][20][21][22][23][24][25][26] and direct measurements of crack velocity via double torsion tests [27,28] have been used to explore the V-K I behavior of brittle materials. The slow crack growth exponent, n, obtained from either indirect or direct methods, describes a materials' resistance to delayed mechanical fatigue [15].…”

Section: Introductionmentioning

confidence: 99%

Slow growth of microcracks in hydroxyapatite during aging

2012

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Hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 or HA) is a brittle material that is subject to environmentally assisted slow crack growth. While most slow crack growth studies are carried out after aging, this study examines the slow growth of radial cracks induced by Vickers indentation in dense HA (94 % of theoretical density) during aging in ambient air, where the observed crack growth is consistent with a process in which residual stress drives crack growth. For indentation loads of 0.98, 1.96, 2.94, and 4.91 N, the average radial crack length increased exponentially with time for indentation loads of 0.98, 1.96, 2.94, and 4.91 N, with crack lengths saturating within 1 h following indentation. However, no radial crack growth was observed for 9.81 N loads. The load dependence of radial crack growth is proposed to be linked to the partitioning of residual strain energy by the lateral crack growth, which has not been reported in the literature.

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“…Hydroxyapatites were synthesized by the reaction of calcium hydroxide with ammonium hydrogen phosphate and (in the case of FHA synthesis) potassium fluoride [8]. The granules were prepared in a two-phase system.…”

Section: Production Of Porous Granules and Ceramic Blocksmentioning

confidence: 99%

Porous apatite biocompatible scaffolds for cell technology for the repair of tissue defects in surgery

et al. 2005

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The problem of repair of tissue defects resulting from extensive operative intervention is very important in surgery. Recent years have seen the development of a basically new concept based on the use of stromal stem cells, whose proliferation and differentiation ensure tissue regeneration [1][2][3]. The implementation of this technology requires porous scaffolds for cell cultivation followed by their implantation into a tissue defect. A promising approach is the use of calcium phosphate ceramic scaffolds. The ceramic should be osteoconductive, cause no adverse response of the organism, and ensure the optimal conditions for protein adsorption and adhesion of osteogenic cells [4,5]. These conditions are met by materials based on hydroxyapatite (HA) [1,6,7].In this paper, we report the results of the design of scaffolds as spherical granules and ceramic blocks obtained by molding of granules followed by heat treatment and having specified dimensions and degree of porosity. The materials were tested in vitro and in vivo to demonstrate their biocompatibility and good prospects for application in reparative plastic surgery. EXPERIMENTAL Production of Porous Granules and Ceramic BlocksMaterials based on HA and fluorohydroxyapatite (FHA) containing up to 10 wt % of fluorine with respect to hydroxy groups were studied. Hydroxyapatites were synthesized by the reaction of calcium hydroxide with ammonium hydrogen phosphate and (in the case of FHA synthesis) potassium fluoride [8]. The granules were prepared in a two-phase system. Suspensions of HA and FHA powders with specific surface areas of 5.5 and 3.7 m 2 /g and an agglomerate size of less than 1 µ m were mixed with an aqueous solution of P-11 gelatine (GOST 11293-89) and dispersed in a liquid dispersion medium (vegetable oil with a viscosity of 0.585 Pa s at 25°ë ) using a paddle stirrer at 200-1000 rpm. During 1 min, nearly spherical granules were formed. These granules were separated on a Büchner funnel, washed, dried, and subjected to heat treatment at 1200°ë for 1 h. The 320-to 500-µ m fraction was isolated by screening the granules on a sieving stack and used to produce porous ceramics and in the subsequent in vitro and in vivo experiments. The linear shrinkage of the granules was determined; the openpore content and size distribution were measured (mercury porosimetry, a Quantachrome Autoscan 1 instrument); the granule morphology and microstructure were measured by scanning electron microscopy (a JEOL JSM-35-CF microscope); and the size distribution of granules was determined (a Coulter Counter instrument). Pressing followed by sintering gave porous ceramic blocks containing two pore populations, namely, intragranular and intergranular pores. Biological AssaysThe porous ceramic granules and blocks were tested in vitro and in vivo. In the in vitro experiments, the properties of the ceramic scaffolds were studied on the human fibroblast (HF) model. The HF cell culture (clone no. 1608) was obtained from the collection of cultures of the Medical Genetic Research Cent...

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Cited by 27 publications

References 7 publications

Sintering and Mechanical Properties of Magnesium and Fluorine Co-Substituted Hydroxyapatites

Sintering and Mechanical Properties of Magnesium and Fluorine Co-Substituted Hydroxyapatites

Slow growth of microcracks in hydroxyapatite during aging

Porous apatite biocompatible scaffolds for cell technology for the repair of tissue defects in surgery

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