Recent estimates of the abundances of the elements in the earth's crust

Fleischer, Michael

doi:10.3133/cir285

Cited by 50 publications

(45 citation statements)

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“…7 Most apatite crystal founded is Ca 10 (PO 4 ) 6 (OH) 2 or known as hydroxyapatite (HA). 2 High concentration levels of fluor on fluorosis enamel suggest the forming of fluorapatite. This forming indicates the substitution OH -by F -on apatite crystal.…”

Section: Discussionmentioning

confidence: 99%

“…1 Fluor is commonly found in volcanoes areas. 2 Most of volcanoes areas were found in Indonesia. This possibility can make the fluorosis spread in some region in Indonesia.…”

Section: Introductionmentioning

confidence: 99%

“…6 Enamel formation is structured by enamel prism which is formed by crystal apatite. 7 Most apatite crystal founded is Ca 10 (PO 4 ) 6 (OH) 2 or known as hydroxyapatite (HA). 2 HA arranged the enamel prism whose length is 120 to 160 nm and width is 25 nm on the narrow side and 40 nm on the wide side.…”

Section: Introductionmentioning

confidence: 99%

“…7 Most apatite crystal founded is Ca 10 (PO 4 ) 6 (OH) 2 or known as hydroxyapatite (HA). 2 HA arranged the enamel prism whose length is 120 to 160 nm and width is 25 nm on the narrow side and 40 nm on the wide side. Each HA crystal is arranged by apatite cell unit in lattice arrangement of P and Ca and also the lattice arrangement of O and H. 8 Every cell unit of apatite suggested Ca ion position on hexagonal corner to form calcium column.…”

Section: Introductionmentioning

confidence: 99%

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Nanostructure of Crystal Hydroxyapatite from Fluorosis: Affected Enamel

Nasution¹

2011

World Journal of Dentistry

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Fluorosis is a condition due to ingestion of excessive amounts of fluor which can cause the change the teeth structure and strength. Currently, a little explanation was available to describe the surface and change of nanostructure crystal hydroxyapatite which contribute to influence the macrocharacteristic of fluorosis enamel. Aims and objectives:To describe the change of surface structure, c-axis, a-axis and grain size of crystal hydroxyapatite on fluorosis enamel. Materials and methods:This research was carried out the fluorosis and normal enamel specimen by using scanning electron microscopy/ energy disperse X-ray (SEM/EDX) to determine fluor concentration and the surfaces structure of fluorosis enamel, and powder X-ray diffraction (XRD) to determine change of c-and a-axis of hydroxyapatite of fluorosis enamel.Results: Fluor concentration were higher in fluorosis enamel and the surface increasingly roughness and porous. SEM/EDX also confirmed gaps areas between enamel rods and visible aprismatic zone in some regions. The axis on fluorosis enamel was a-axis = 9.3786 Å and c-axis = 6.8836 Å. The a-axis on normal enamel was = 9.4148 Å and c-axis = 6.8791 Å. Grain size of fluorosis enamel was 19.59 nm and normal enamel was 20.30 nm. Conclusion:Fluor as most electronegative element changes the c-axis, a-axis, and grain size of crystal hydroxyapatite and generates the internal atomic bonding which influences the stability of enamel strength.

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Section: Discussionmentioning

confidence: 99%

“…1 Fluor is commonly found in volcanoes areas. 2 Most of volcanoes areas were found in Indonesia. This possibility can make the fluorosis spread in some region in Indonesia.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Nanostructure of Crystal Hydroxyapatite from Fluorosis: Affected Enamel

Nasution¹

2011

World Journal of Dentistry

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“…1,200 1,320 1,000 625 595 570 1,000 1,208 1,000 800 40 26 640 779 18 680 635 2, Available data indicate that the earth's crust contains about 00 006 percent lithium (Fleischer, 1953, pe 4 0 table 2) 0 Rankama and Sahama (1950,, p0 422-428) show that igneous rocks contain an average of about 00 0065 percent Iithium0 and sedimentary rocks contain somewhat Iess0…”

Section: History Of Lithium Mining and Productionmentioning

confidence: 99%