Mechanical properties of sintered hydroxyapatite for prosthetic applications

Akao, Masaru; Aoki, Hideki; Kato, Kuniki

doi:10.1007/bf00552220

Cited by 105 publications

(131 citation statements)

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“…It should be noted that a wide range of values has been proposed in different studies: with the TC molecule values ranging from 0.35 to 12 GPa (Gautieri et al, 2011;Sun et al, 2002) and from 62.75 to 170 GPa for HA mineral (Weiner and Wagner, 1998;Cowin, 1989;Currey, 1969). The failure properties of TC molecules and mineral reported in literature (Akao et al, 1981;Shareef et al, 1993) are shown in Table 1.…”

Section: Mineralized Collagen Microfibrilmentioning

confidence: 94%

Effect of material and structural factors on fracture behaviour of mineralised collagen microfibril using finite element simulation

Barkaoui¹,

Hambli²,

Tavares³

2014

Computer Methods in Biomechanics and Biomedical Engineering

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Bone is a multiscale heterogeneous material and its principal function is to support the body structure and to resist mechanical loads without fracturing. Numerical modelling of biocomposites at different length scales provides an improved understanding of the mechanical behaviour of structures such as bone, and also guides the development of multiscale mechanical models. Here, a three-dimensional nano-scale model of mineralized collagen microfibril based on the finite element method was employed to investigate the effect of material and structural factors on the mechanical equivalent of fracture properties.

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Section: Mineralized Collagen Microfibrilmentioning

confidence: 94%

Effect of material and structural factors on fracture behaviour of mineralised collagen microfibril using finite element simulation

Barkaoui¹,

Hambli²,

Tavares³

2014

Computer Methods in Biomechanics and Biomedical Engineering

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“…Synthetic, phase pure, dense, polycrystalline HA pellets (~1 cm in diameter) were prepared by an aqueous precipitation reaction between calcium hydroxide and phosphoric acid as described previously [5]. The pellets were found to be >98% of the theoretical density (3.13±0.015 g/cm 3 ), highly crystalline, phase pure, and approximately stoichiometric (Ca/P ratio=1.67) as measured by water displacement, wide angle X-ray diffraction, and X-ray fluorescence [6].…”

Section: Methodsmentioning

confidence: 99%

Nanoscale Morphology of Apatite Precipitated onto Synthetic Hydroxyapatite from Simulated Body Fluid

Vandiver¹,

Patel

Bonfield

et al. 2005

KEM

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Abstract. Dense, polycrystalline, synthetic hydroxyapatite (HA) was incubated for 36 days in modified simulated body fluid (SBF) with increased HCO 3 -and reduced Cl -ion concentrations (27 and 120 mM, respectively) closer to actual blood plasma than typical SBF. The resulting precipitated apatite layer was characterized by X-ray photoelectron spectroscopy (XPS) and contact angle measurements and found to be nonstoichiometric, calcium deficient (Ca/P~1.06), noncarbonate containing, and of intermediate hydrophilicity (advancing contact angle, θ a =76.5±1.3°). The nanoscale surface topography of the SBF-incubated HA sample was imaged by tapping mode atomic force microscopy (TMAFM), observed to be =100 nm in thickness, and composed of three distinct morphologies. These topographically distinct regions were localized within individual grains and facets of the initial HA surface and included: hemispherical, globular structures (maximum lateral dimension, d=44.7±12.7 nm, peak-to-valley height, h=3.6±2.7 nm); elongated, needle-like structures (minimum lateral dimension, w=31.0±8.5 nm, d=104.4±31.1 nm, h=5.0±3.2 nm), and regions of larger, irregularly shaped structures that were relatively smooth (d=504.9±219.1 nm, h=104.0±51.7 nm). IntroductionSynthetic hydroxyapatite (HA, Ca 5 (PO 4 ) 3 OH), HA-based biomaterials, and HA coatings are used extensively for hard tissue applications due to their bioactivity [1]. Upon implantation in vivo [2] or incubation in vitro in simulated body fluid (SBF) [3], an apatite layer forms on the surface which is considered essential for the nucleation of biological apatite, the promotion of protein adsorption and cell adhesion, and ultimately, the creation of a strong bond with the surrounding tissue [4]. The objective of this study was to directly visualize and quantify the nanoscale topography of apatite precipitated in vitro from SBF onto dense, polycrystalline, phase pure HA using tapping mode atomic force microscopy (TM AFM) imaging, which enables spatial resolutions of <1 nm. New information is presented on the morphological heterogeneity of the apatite layer, as well as the nature of the transition boundarie s between topographically different regions. Such a methodology has great potential to contribute insights into the physiochemical mechanisms and temporal evolution of HA interfacial apatite layers and molecular origins of their bone bonding capability.

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“…β = σ Akao et al [1981] and Shareef et al [1993], see [Fritsch et al, 2009] for further details, and they amount to 52.2 MPa and 80.3 MPa, respectively (see also Table 2). Beyond the elastic regime, we consider associated ideal plasticity according to Eq.…”

Section: Failure Properties Of Hydroxyapatite Crystals and Collagenmentioning

confidence: 99%

Ductile sliding between mineral crystals followed by rupture of collagen crosslinks: Experimentally supported micromechanical explanation of bone strength

Fritsch

Hellmich

Dormieux

2009

Journal of Theoretical Biology

176

128

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To cite this version:Andreas Fritsch, Christian Hellmich, Luc Dormieux.Ductile sliding between mineral crystals followed by rupture of collagen crosslinks: Experimentally supported micromechanical explanation of bone strength. Journal of Theoretical Biology, Elsevier, 2009, 260 (2) This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.A c c e p t e d m a n u s c r i p t AbstractThere is an ongoing discussion on how bone strength could be explained from its internal structure and composition. Reviewing recent experimental and molecular dynamics studies, we here propose a new vision on bone material failure: mutual ductile sliding of hydroxyapatite mineral crystals along layered water films is followed by rupture of collagen crosslinks. In order to cast this vision into a mathematical form, a multiscale continuum micromechanics theory for upscaling of elastoplastic properties is developed, based on the concept of concentration and influence tensors for eigenstressed microheterogeneous materials. The model reflects bone's hierarchical organization, in terms of representative volume elements for cortical bone, for extravascular and extracellular bone material, for mineralized fibrils and the extrafibrillar space, and for wet collagen. In order to get access to the stress states at the interfaces between crystals, the extrafibrillar mineral is resolved into an infinite amount of cylindrical material phases oriented in all directions in space. The multiscale micromechanics model is shown to be able to satisfactorily predict the strength characteristics of different bones from different species, on the basis of their mineral/collagen content, their intercrystalline, intermolecular, lacunar, and vascular porosities, and the elastic and strength properties of hydroxyapatite and (molecular) collagen. Preprint submitted to Journal of Theoretical Biology 6 May 2009A c c e p t e d m a n u s c r i p t

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Mechanical properties of sintered hydroxyapatite for prosthetic applications

Cited by 105 publications

References 0 publications

Effect of material and structural factors on fracture behaviour of mineralised collagen microfibril using finite element simulation

Effect of material and structural factors on fracture behaviour of mineralised collagen microfibril using finite element simulation

Nanoscale Morphology of Apatite Precipitated onto Synthetic Hydroxyapatite from Simulated Body Fluid

Ductile sliding between mineral crystals followed by rupture of collagen crosslinks: Experimentally supported micromechanical explanation of bone strength

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