An electron microscopic study of the formation of amorphous calcium phosphate and its transformation to crystalline apatite

Eanes, E. D.; Termine, John D.; Nylen, Marie U.

doi:10.1007/bf02013730

Cited by 195 publications

(121 citation statements)

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“…ACP is thought to be formed at the beginning of the deposition due to a lower surface energy than OCP and apatite. 20 There are small crystalline particles (parallel lines identified with arrows) with a size of 2-3 nm. The FFT pattern (Fig.…”

Section: Resultsmentioning

confidence: 99%

Ultrastructural analyses of nanoscale apatite biomimetically grown on organic template

et al. 2008

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The ultrastructure of nanoscale apatite biomimetically formed on an organic template from a supersaturated mineralizing solution was studied to examine the morphological and crystalline arrangement of mineral apatites. Needle-shaped apatite crystal plates with a size distribution of ~100 to ~1000 nm and the long axis parallel to the c axis ([002]) were randomly distributed in the mineral films. Between these randomly distributed needle-shaped apatite crystals, amorphous phases and apatite crystals (~20-40 nm) with the normal of the grains quasi-perpendicular to the c axis were observed. These observations suggest that the apatite film is an interwoven structure of amorphous phases and apatite crystals with various orientations. The mechanisms underlying the shape of the crystalline apatite plate and aggregated apatite nodules are discussed from an energy-barrier point of view. The plate or needle-shaped apatite is favored in single-crystalline form, whereas the granular nodules are favored in the polycrystalline apatite aggregate. The similarity in shape in both singlecrystalline needle-shaped apatite and polycrystalline granular apatite over a wide range of sizes is explained by the principle of similitude, in which the growth and shape are determined by the forces acting upon the surface area and the volume.

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Section: Resultsmentioning

confidence: 99%

Ultrastructural analyses of nanoscale apatite biomimetically grown on organic template

et al. 2008

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“…In skeletal calcification, ACP is a key intermediate that is formed prior to biological apatite formation 17) . As to what occurs after the spontaneous precipitation of ACP and its subsequent transformation into crystalline apatite, these aspects have also been extensively investigated 23,24) . Hence, since MTA had a high alkalinity at pH>12, it was highly probable that ACP would transform to crystalline apatite instead of octacalcium phosphate 25) .…”

Section: Discussionmentioning

confidence: 99%

Morphological and chemical analysis of different precipitates on mineral trioxide aggregate immersed in different fluids

2010

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The purpose of this study was to analyze the ultrastructures and chemical compositions of precipitates formed on mineral trioxide aggregate (MTA; White ProRoot MTA) immersed in distilled water (DW) or phosphate buffered saline (PBS), based on the attribution that MTA's bioactivity and sealing ability are influenced by its interaction with the external fluid environment. After 1 and 14 days of immersion, precipitates formed on MTA disks were analyzed using wavelength-dispersive X-ray spectroscopy electron probe microanalyzer with image observation function (SEM-EPMA; EPMA1601, Shimadzu, Kyoto, Japan), and Fourier transform-infrared (FT-IR) spectroscopy. On DW specimens, cubic-like crystals containing Ca, O, and C (17, 66, and 17 at% respectively) were produced. State analysis of calcium kβ spectrum also revealed calcium hydroxide. On PBS specimens, acicular-spherical and lath-like crystals with Ca/P molar ratios of 1.42 and 1.58 respectively were produced. In conclusion, the precipitates formed on DW specimens were identified as calcium carbonate and calcium hydroxide primarily, whereas the precipitates on PBS specimens were inferred to be amorphous calcium phosphate.

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“…These components appear to be almost identical to the components of bone nodules which were indicated by Bernard and Pease (1969). These findings lead to the hypothesis that these extracellular matrix components in the primary intramembranous osteogenesis may interact with precursors of HA as suggested by Eanes et al (1973). It can not be excluded the possibility that the matrix components interacting with implanted precursors may involve growth factors such as bone morphogenetic protein (Urist 1976), transforming growth factor f3 and so on (Canalis et al 1988).…”

Section: Light Microscopic Findingsmentioning

confidence: 91%

“…The interaction has been suggested between HA crystals and collagens (Glimcher et al 1957) or noncollagenous proteins in bone and teeth such as osteocalcin (Hauschka et al 1975), osteonectin (Termine et al 1981), bone phosphoproteins including osteopontin (Glimcher et al 1979) and sialoproteins and proteoglycans (Fisher et al 1987). Eanes et al (1973) have suggested that ACP could be the nucleating locus for bone nodules which were described as the developmental units of bone (Bernard and Pease 1969), because of general similarity in appearance between bone nodules and clusters of synthetic HA formed by conversion of ACP. Nelson and Barry (1989) have postulated that the involvement of biological macromolecules with crystal nucleation and growth processes are most probably by steric interactions, adsorption, and crystal growth inhibition or possibly by reducing the energy barrier for nucleation of the OCP seed.…”

Section: Light Microscopic Findingsmentioning

confidence: 99%

“…Termine and Conn (1976) have presented that phosphorylated metabolites and macromolecules are incorporated into ACP, and inhibit amorphous-crystalline conversion in vitro . Although the precursors of HA were suggested to be associated with the nucleating focus in organic matrix components (Eanes et al 1973), functional role of the precursor phases of HA in vivo still remains to be not clear.…”

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Bone Formation on Synthetic Precursors of Hydroxyapatite.

Сузукі

Nakamura

Miyasaka

et al. 1991

Tohoku J. Exp. Med.

261

312

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The aim of this study was to investigate the reaction of skeletal tissue to various synthetic calcium phosphate (Ca-P) compounds in vivo. Five synthetic Ca-P compounds were implanted into the subperiosteal area of the calvaria of 7-week-old BALB/c mice for one to 15 weeks. Synthetic compounds were dicalcium phosphate (DCP), octacalcium phosphate (OCP), amorphous calcium phosphate (ACP), Ca-deficient hydroxyapatile and hydroxyapatile (HA). Implanted DCP, OCP and ACP were found to be converted to apatitic phase by x-ray microdiffraction analysis using undecalcified specimens. Structure of bone was found out on all of Ca-P compounds eventually at late stage under the light microscope, but the rate of bone formation calculated from a number of experiments varied on respective synthetic Ca-P compound. It was high as 80% for DCP, OCP and ACP, but was low as 5.6% for Ca-deficient HA, and no reaction was found for HA at the stage of 3 weeks. Fine filaments and granular materials in the newly formed bone matrix were detected at 7 days around the remnants of OCP particles which already converted to apatitic phase by ultrastructural study of decalcified specimens. These structures were very similar to the components of bone nodules seen in intramembranous osteogenesis. It is postulated that the precursors of HA have an important role in intramembranous osteogenesis.calcium phosphate (Ca-P) compounds ; precursors ; hydroxyapatile ; bone formation ; bone matrix

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An electron microscopic study of the formation of amorphous calcium phosphate and its transformation to crystalline apatite

Cited by 195 publications

References 14 publications

Ultrastructural analyses of nanoscale apatite biomimetically grown on organic template

Ultrastructural analyses of nanoscale apatite biomimetically grown on organic template

Morphological and chemical analysis of different precipitates on mineral trioxide aggregate immersed in different fluids

Bone Formation on Synthetic Precursors of Hydroxyapatite.

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