Fabrication of Potassium-Substituted Hydroxyapatite Ceramics via Ultrasonic Spray-Pyrolysis Route

Yokota, Tomohiro; Honda, Michiyo; Aizawa, Mamoru

doi:10.3363/prb.33.35

Cited by 12 publications

(11 citation statements)

References 13 publications

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“…Contraction of the lattice parameter "a" takes place as a result of the presence of these created additional hydroxide vacancies. However, another study reported increments in both lattice parameters with the addition of K [166]. Due to the higher ionic radius (1.33 Å), it might be expected that K + would prefer the Ca(2) site for substitution, but the experimental findings show the opposite trend [167].…”

Section: Monovalent Cationsmentioning

confidence: 97%

Doped biphasic calcium phosphate: synthesis and structure

Basu

2019

Journal of Asian Ceramic Societies

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Hydroxyapatite, tricalcium phosphate, and a mixture of these, i.e biphasic calcium phosphate (BCP), are widely employed as ceramic materials in hard tissue engineering, despite their poor mechanical and functional properties. The method of ionic substitution inside their lattice structures has been examined extensively by researchers in their long efforts to develop materials, that closely resemble natural hard tissues. The presence of dopants has a deep impact on the phase assemblage, structural, and functional behaviors of BCP. In this context, the goal of the current article is to cover different aspects of ongoing research on doped biphasic calcium phosphate. Apart from providing brief descriptions of different synthesis routes for producing ion-modified BCPs, the limitations of each technique are also discussed. In addition, particular emphasis has been given to describing the key experimental results, which elucidate the structural changes occurring due to doping. In particular, the preferable substitution sites of different dopant ions and the resulting crystallographic changes are depicted quite elaborately. Finally, the effects of substitution on biological and mechanical properties of BCP are briefly mentioned. In summary, the present review focuses on the ionic substitutions in BCP systems and their collective effects on material behaviors.

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Section: Monovalent Cationsmentioning

confidence: 97%

Doped biphasic calcium phosphate: synthesis and structure

Basu

2019

Journal of Asian Ceramic Societies

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“…In our previous study focused on cation doping, Yokota et al [9,10] fabricated sodium-or potassiumsubstituted HAp. They have also successfully fabricated bone HAp ceramics, including bone minerals with six types of ions; Na + , K + , Mg 2+ , F − , Cl − and CO 3 2− .…”

Section: Introductionmentioning

confidence: 99%

“…As described above, a number of studies have reported the effects of cations in biological apatite [3][4][5][6][7][8][9][10][11]. An artificially obtained material may have promoted bioactivity by the effect of substituted ions; for example, magnesium ions promote bone formation [14].…”

Section: Introductionmentioning

confidence: 99%

Development of nitrogen-doped hydroxyapatite ceramics

Kaneko

Suzuki

Umeda

et al. 2020

Journal of Asian Ceramic Societies

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Hydroxyapatite (Ca 10 (PO 4) 6 (OH) 2 ; HAp) is widely used as a biomaterial due to its high biocompatibility. However, biological apatite present in bone and teeth contains various ions in the HAp crystal structure. Thus, biological apatite has many strains and defects, which may impart high osteoconductivity to apatite. To clarify the effects of the strain and/or defects in the HAp crystal structure on the bioactivity, nitrogen-doped (N-doped) HAp ceramics were fabricated by heating pure HAp ceramics. This N-doped method is well-known as a technique to modify the chemical structure at the surface. Some properties of the N-doped HAp ceramics were examined for optimization of the heating temperature. N-doped HAp ceramics fabricated by heating at 850°C in an NH 3 atmosphere had N 2 O molecules in the crystal structure. Therefore, the N-doped HAp ceramics fabricated by the N-doping method have a rare moleculesubstitution structure. In conclusion, we have developed the N-doped HAp ceramics which have a rare molecule-substitution structure.

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“…The calculation results by the least squares method listed in Table 1 showed a particular decrease for a parameter while c parameter was slightly varied. The a variation was governed by two antagonist effects: firstly, the substitution of K + (0.138 nm) for Ca 2+ (0.100 nm) induced an increase in the a values; however, as it was reported in the literature, the substitution of a divalent cation by a monovalent one decreased the channel diameter of a parameter and in consequence, a markedly decreased [28,29,31]. Secondly, the bibliography on hydroxfluorapatites reported that a parameter increased with a decreasing degree of fluoridation [36,37].…”

Section: Phase Analysismentioning

confidence: 64%

“…Moreover, potassium is indispensable for bone nucleation and biomineralization processes [27]. The literature reports have revealed that doping by potassium has occurred without any significant effects on the structural stability of apatites, and that ~20 atom.% were introduced into the apatite structure [28][29][30]. Meanwhile, lattice parameters slightly decreased when the level of substituted K + increased.…”

Section: Introductionmentioning

confidence: 99%

Sintering of Potassium Doped Hydroxy-Fluorapatite Bioceramics

et al. 2021

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The present study describes the influence of potassium and hydroxyl substitutions on the structural, thermal and mechanical properties of fluorapatite bioceramics. A set of non-stoichiometric ion-substituted compounds, with a chemical formula of Ca10−xKx(PO4)6F(2−2x)(OH)x with 0 ≤ x ≤ 1 synthesized by the wet precipitation method, were found to be single-phase apatites crystallizing in the hexagonal P63/m space group. The structural parameters, as well as the crystallite sizes, increased accordingly to the amount of added dopant-ions. The thermal behavior of these compounds, studied within the temperature range 500–1200 °C, indicated a partial decomposition of the apatitic phase and its transformation to tricalcium phosphate β-Ca3(PO4)2 at temperatures exceeding 750 °C. A relative density of the sintered samples achieved the highest value with x = 0.25 and reached about 95% after sintering at 1050 °C for 1 h. The microstructures of the sintered samples were of a trans-granular aspect and experienced an increase in the radius of their pores as x increased. The prepared bioceramic materials were mechanically characterized by means of Young’s modulus, flexural strength and fracture toughness measurements. The overall trend of these parameters evolved comparably to the relative density, and the maximum values obtained for x = 0.25 were measured to be 96 MPa, 47 MPa and 1.14 MPa·m1/2, respectively.

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Fabrication of Potassium-Substituted Hydroxyapatite Ceramics via Ultrasonic Spray-Pyrolysis Route

Cited by 12 publications

References 13 publications

Doped biphasic calcium phosphate: synthesis and structure

Doped biphasic calcium phosphate: synthesis and structure

Development of nitrogen-doped hydroxyapatite ceramics

Sintering of Potassium Doped Hydroxy-Fluorapatite Bioceramics

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