Transmission electron microscopic study of calcium phosphate formation in supersaturated solutions seeded with apatite

Doi, Yutaka; Eanes, E. D.

doi:10.1007/bf02405292

Cited by 30 publications

(8 citation statements)

References 24 publications

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“…Thus, remineralization of a partially-demineralized collagen matrix is thermodynamically more favorable than homogeneous nucleation within a completely-demineralized collagen matrix. Part of the success reported with the use of contemporary calcium- and phosphate-releasing remineralizing materials may be related to the remineralization of the collagen matrix via epitaxial growth of calcium phosphate salts on remnant seed crystallites [23]. Epitaxial growth may be regarded as a top-down approach according to the classical crystallization theory, via ion-by-ion addition to pre-existing seed crystallites [14].…”

Section: Introductionmentioning

confidence: 99%

Functional biomimetic analogs help remineralize apatite-depleted demineralized resin-infiltrated dentin via a bottom–up approach

et al. 2010

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Natural biominerals are formed through metastable amorphous precursor phases via a bottom-up, nanoparticle-mediated mineralization mechanism. Using an acid-etched human dentin model to create a layer of completely-demineralized collagen matrix, a bio-inspired mineralization scheme has been developed based on the use of dual biomimetic analogs. These analogs help to sequester fluidic amorphous calcium phosphate nanoprecursors and function as templates for guiding homogeneous apatite nucleation within the collagen fibrils. By adopting this scheme for remineralizing adhesive resin-bonded, completely-demineralized dentin, we have been able to redeposit intrafibrillar and extrafibrillar apatites in completely-demineralized collagen matrices that are imperfectly infiltrated by resins. This study utilizes a spectrum of completely- and partially-demineralized dentin collagen matrices to further validate the necessity for using a biomimetic analog-containing medium for remineralizing resin-infiltrated partially-demineralized collagen matrices in which remnant seed crystallites are present. In control specimens in which biomimetic analogs are absent from the remineralization medium, remineralization could only be seen in partially-demineralized collagen matrices probably by epitaxial growth via a top-down crystallization approach. Conversely, in the presence of biomimetic analogs in the remineralization medium, intrafibrillar remineralization of completely-demineralized collagen matrices via a bottom-up crystallization mechanism can additionally be identified. The latter is characterized by the transition of intrafibrillar minerals from an inchoate state of continuously-braided microfibrillar electron-dense amorphous strands to discrete nanocrystals, and ultimately into larger crystalline platelets within the collagen fibrils. Biomimetic remineralization via dual biomimetic analogs has the potential to be translated into a functional delivery system for salvaging failing resin-dentin bonds.

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Section: Introductionmentioning

confidence: 99%

Functional biomimetic analogs help remineralize apatite-depleted demineralized resin-infiltrated dentin via a bottom–up approach

et al. 2010

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“…In the latter study, we suppose that Ca/P of 1.34 indicated that the HOS cells would formed OCP. Ca binding sites and Ca receptors are likely to be involved initial process of OCP formation in vivo (Chattopadhyay N et al, 1996;Nancollas GH et al, 1974;Doi Y et al, 1984). There is a possibility of epitaxial relationship of HA, and HA is present epitaxially on the OCP surface whereas OCP is a precursor to HA (Brown WE et al, 1962, 1966, 1987Cheng PT, 1987).…”

Section: Discussionmentioning

confidence: 99%

Morphological Character of Crystalline Components Present in Saiga Horn

Hashiguchi

Hashimoto

Akao

2001

Okajimas Folia Anatomica Japonica

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Summary: The purpose of this study was to investigate the ultrastructure of saiga-antelope (Saiga tatarica) horn for proposing the mechanism of the initial mineralization. Horn is derived from horny tooth of Cyclostomata. The minerals in saiga horn were identified crystallographically using electron microscopy and X-ray diffraction techniques. Soft X-ray photographs revealed the degree of the mineralization pattern. However, the number of rings did not indicate the age of saiga.Mineral deposites were observed among well banded keratin fibers and composed of powder like crystals. This deposited crystals were found by the X-ray diffraction method to be octacalcium phospate (OCP) by comparing these periodic lattice fringes to JCPDS card data The chemical formula of OCP is Ca8H2(PO4)6 5H2O. Evidences for the presence of OCP in mature hard tissues have never been obtained. This phenomenon described here may be characteristic of saiga horn because we have found no reports on this type of OCP mineralization in any other animal species. It is possible that OCP is the precursor in the initial mineralization step, indicating in a nucleation of mineral on the keratin fibers.

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“…5 and 10) . It has been demonstrated that the morphology of the deposited apatite changes depending on the degree of solution supersaturation 31) . According to this finding, deposition of the plate-like crystals formed on the heated titanium substrate seemed to be due to a high degree of solution supersaturation achieved by increasing the temperature of the metastable solution in contact with the substrate.…”

Section: Morphology Of the Deposited Ha Crystalsmentioning

confidence: 99%

Hydroxyapatite Film Coating by Thermally Induced Liquid-phase Deposition Method for Titanium Implants

et al. 2006

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INTRODUCTIONCalcium phosphate ceramics, especially synthetic apatites, have been studied as biocompatible materials for bone reconstruction and bone filling 1-5） . It has been demonstrated that hydroxyapatite （HA） coatings on titanium implants facilitate rapid bone formation due to their osteoconductive property 6-10） . Plasma-sprayed HA-coated dental implants have been used clinically, and good results have been obtained 11-13） . Physical vapor deposition techniques, such as ion implantation 14） , ion beam mixing 15）, and ion beam dynamic mixing 16） have recently been used for fabricating thin HA layers with strong adherence on titanium substrates. These dry process techniques, including plasma spraying, are suitable for forming uniform HA films on implants with smooth surfaces. However, uniform coatings of thin HA layer on irregularly shaped implants and within the pores of porous-surfaced implants cannot be achieved by using these techniques. The formation of a thin and uniform HA layer on the inner surfaces of pores as well as the outside surface would facilitate bone ingrowth into the porous layer, thus improving the implant fixation due to improved mechanical retention. Wet process techniques for HA film coating are therefore attractive for coating of poroussurfaced implants.Many methods for HA film coating by a wet process, including dip coating 17,18） , electrolytic deposition 19,20） , and anodic oxidation followed by hydrothermal treatment 21） , have been proposed.These methods, however, have not been employed in clinical practice. This is probably because they do not satisfy all the requirements for clinical application, such as sufficient bonding between HA coating and underlying substrate, uniformity of the coated HA layer, a simple and quick coating process, and long-term stability of the coated HA layer. The solubility product of HA decreases with increase in temperature above 16℃ 22）. As such, an HA film can be quickly formed from heterogeneous nucleation on a titanium substrate when the substrate is electrically heated in a metastable calcium phosphate solution. Based on this principle, Kuroda et al.23） demonstrated that HA crystals could be deposited on a polished titanium plate. However, they did not obtain a dense and uniform HA film when the titanium plate was electrically heated at 45 -160℃ in a calcium phosphate solution 23）. This was probably due to insufficient induction of heterogeneous HA nucleation on the polished titanium plate by electrical heating.In the present study, we chemically modified the surface of a titanium substrate prior to heating it in a metastable calcium phosphate solution. The purpose of which was to promote heterogeneous HA nucleation and thus form a uniform HA film rapidly. The titanium substrate was alkaline-treated in 5 M NaOH at 60℃ for 24 hours, and then heated at 60 ℃ for 0.5 -3 hours in a metastable calcium phosphate solution that does not precipitate spontaneously. The HA film that formed on the substrate was examined by scanning electron mic...

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Transmission electron microscopic study of calcium phosphate formation in supersaturated solutions seeded with apatite

Cited by 30 publications

References 24 publications

Functional biomimetic analogs help remineralize apatite-depleted demineralized resin-infiltrated dentin via a bottom–up approach

Functional biomimetic analogs help remineralize apatite-depleted demineralized resin-infiltrated dentin via a bottom–up approach

Morphological Character of Crystalline Components Present in Saiga Horn

Hydroxyapatite Film Coating by Thermally Induced Liquid-phase Deposition Method for Titanium Implants

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