Synthesis and characterization of magnesium substituted biphasic mixtures of controlled hydroxyapatite/β-tricalcium phosphate ratios

Kannan, S.; Lemos, Isabel Alexandra Fernandes; Rocha, João; Ferreira, J.M.F.

doi:10.1016/j.jssc.2005.08.003

Cited by 138 publications

(123 citation statements)

References 27 publications

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“…Refinements of the site occupancy factors for the calcium and hydroxide sites in the HAp structure did not evidence a nonstoichiometry. All of the refined occupancy parameters were very close to a full site filling, in agreement with the literature, which indicates that the HAp phase is stoichiometric (with a Ca/P ratio of 1.67) when calcined above the temperature of 700°C (10,31,32).…”

Section: Resultssupporting

confidence: 88%

Structural Characterization and Biological Fluid Interaction of Sol−Gel-Derived Mg-Substituted Biphasic Calcium Phosphate Ceramics

Gomes

Renaudin

Jallot

et al. 2009

ACS Appl. Mater. Interfaces

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Sol-Gel chemistry has been used to prepare undoped and Mg-substituted biphasic calcium phosphate (BCP) ceramics composed of hydroxyapatite (HAp) and whitlockite ( -TCP) phases. Different series of samples have been synthesized with different Mg-doping levels (from 0 to 5 atomic % of Ca atoms substituted) and different temperatures of calcination (from 500 to 1100°C). All of the powdered samples were systematically treated by Rietveld refinement to extract the quantitative phase analysis and the structural and microstructural parameters, to locate the Mg crystallographic sites, and to refine the composition of the Mg-substituted phases. The temperature dependence of the weight amount ratio between HAp and -TCP is not monotonic because of the formation of minor phases such as Ca 2 P 2 O 7 , CaO, MgO, and CaCO 3 and certainly an amorphous phase. On the other hand, the Mg stabilizing feature on the -TCP phase has been evidenced and explained. The mechanism of stabilization by small Mg 2+ is different from that by large Sr 2+ . Nevertheless, in both cases, the -TCP stabilization is realized by an improvement of the environment of the Ca4 site unusually face-coordinated to a PO 4 tetrahedron. The substitution of a Mg atom in the Ca5 site allows considerable improvement of the bond valence sum of the unusual Ca4 polyhedron. The temperatures of calcination combined with the amount of Mg atoms introduced allow monitoring of the phase composition of the BCP ceramics as well as their microstructural properties. The bioactivity properties of the BCP samples are improved by the presence of Mg atoms in the structure of the -TCP phase. The mechanism of improvement is mainly attributed to an accelerated kinetic of precipitation of a calcium phosphate layer at the surface comprising HAp and/or -TCP phases.

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Section: Resultssupporting

confidence: 88%

Structural Characterization and Biological Fluid Interaction of Sol−Gel-Derived Mg-Substituted Biphasic Calcium Phosphate Ceramics

Gomes

Renaudin

Jallot

et al. 2009

ACS Appl. Mater. Interfaces

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“…The patterns of MHA and MHF 0.5 A showed the presence of -MTCP, indicating the decomposition of MHA, as has been reported in the literature [19,20,39,40]. This phase remained stable up to 1300˚C [18]. Indeed, it is well-known that the Mg substitution stabilizes the -TCP phase at temperatures above 1300˚C [18].…”

Section: Sintering Of Powderssupporting

confidence: 75%

“…On the other hand, Magnesium has a beneficial effect on the mineralization processes [13,14], osteoporosis [15] and might play a role on the osteoblastic and osteoclastic activities [16,17]. In addition, Mg is known to inhibit the crystallization of the hydroxyapatite, increase its dissolution and affect its thermal stability by lowering its decomposition temperature [18][19][20]. Thus, ceramics designed from hydroxyapatite containing magnesium and fluorine would be more suitable for dental and orthopedic applications.…”

Section: Introductionmentioning

confidence: 99%

Sintering and Mechanical Properties of Magnesium and Fluorine Co-Substituted Hydroxyapatites

Nsar¹,

Hassine²,

Bouzouita³

2013

JBNB

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Biological apatites contain several elements as traces. In this work, magnesium and fluorine co-substituted hydroxyapatites with the general formula Ca 9 Mg(PO 4 ) 6 (OH) 2-y F y , where y = 0, 0.5, 1, 1.5 and 2 were synthesized by the hydrothermal method. After calcination at 500˚C, the samples were pressureless sintered between 950˚C and 1250˚C. The substitution of F − for OH − had a strong influence on the densification behavior and mechanical properties of the materials. Below 1200˚C, the density steeply decreased for y = 0.5 sample. XRD analysis revealed that compared to hydroxylfluorapatite containing no magnesium, the substituted hydroxyfluorapatites decomposed, and the nature of the decomposition products is tightly dependent on the fluorine content. The hardness, elastic modulus and fracture toughness of these materials were investigated by Vickers's hardness testing. The highest values were 622 ± 4 GPa, 181 ± 1 GPa and 1.85 ± 0.06 MPa·m 1/2 , respectively.

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“…3 because of the potential beneficial effects of Mg on the physicochemical properties of the minerals [14,15] and also because the improvement of the bone metabolism [16].…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

“…After 30 min, they were rinsed again and kept in PBS at 4 ºC. After cell fixation, the specimens were dehydrated in ethanol solutions of varying concentration (15,30,50,70,90, and 100 %) for about 30 min at each concentration. The specimens were then dried, using the critical-point dry technique, and subsequently they were coated with carbon using the evaporator Balzers MED-010 (Balzers Union, Liechtenstein), and then coated with gold using metallization K550X…”

Section: Cell Morphologymentioning

confidence: 99%

Magnesium substitution in brushite cements for enhanced bone tissue regeneration

Cabrejos-Azama

Alkhraisat

Rueda

et al. 2014

Materials Science and Engineering: C

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We have synthesized calcium phosphate cements doped with different amounts of magnesium (Mg-CPC) with a twofold purpose: i) to evaluate in vitro the osteoblast cell response to this material, and ii) to compare the bone regeneration capacity of the doped material with a calcium cement prepared without magnesium (CPC). Cell proliferation and in vivo response increased in the Mg-CPCs in comparison with CPC. The Mg-CPCs have promoted higher new bone formation than the CPC (p < 0.05). The cytocompatibility and histomorfometric analysis performed in the rabbit calvaria showed that the incorporation of magnesium ions in CPC improves osteoblasts proliferation and provides higher new bone formation. The development of a bone substitute with controllable biodegradable properties and improved bone regeneration can be considered a step towards personalized therapy that can adapt to patient needs and clinical situations.

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Synthesis and characterization of magnesium substituted biphasic mixtures of controlled hydroxyapatite/β-tricalcium phosphate ratios

Cited by 138 publications

References 27 publications

Structural Characterization and Biological Fluid Interaction of Sol−Gel-Derived Mg-Substituted Biphasic Calcium Phosphate Ceramics

Structural Characterization and Biological Fluid Interaction of Sol−Gel-Derived Mg-Substituted Biphasic Calcium Phosphate Ceramics

Sintering and Mechanical Properties of Magnesium and Fluorine Co-Substituted Hydroxyapatites

Magnesium substitution in brushite cements for enhanced bone tissue regeneration

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