Hydroxylapatite with substituted magnesium, zinc, cadmium, and yttrium. I. Structure and microstructure

Abstract

Hydroxylapatite (HA) was made containing magnesium, zinc, cadmium, and yttrium. Salts of these cations were added to precipitating HA; the precipitates were dried and sintered at 1100 degrees C for 1 h. Lattice parameters from X-ray diffraction spectra showed that these elements were incorporated into the apatite structure at a level of 2% added fraction of calcium in HA and up to 7% for yttrium. The densities of different substituted apatites were close to theoretical for pressed and sintered samples, which is evidence for low bulk porosity. The grain sizes of substituted apatites were smaller than those of pure HA except for cadmium-containing apatite. Surfaces of etched samples showed no second phases, whereas surfaces of unetched samples showed second phases and higher porosity than etched surfaces.

Effect of milk minerals on calf gains and sex differences in mineral composition of milk from Iberian red deer (Cervus elaphus hispanicus)

“…This is clearly not a compensatory response, as males grow faster than females. In addition to other roles, Mg plays an important role in bone formation because it can substitute Ca in bone hydroxyapatite, and in fact, 3% of bone is formed by Mg 3 (PO 4 ) 2 (Doyle 1979, Ergun et al 2002. The reason for a higher Mg content in milk for males might be linked to the role Mg plays in the skeleton because 70% of the body reserves of Mg are in the skeleton (Doyle 1979).…”

“…The reason for a higher Mg content in milk for males might be linked to the role Mg plays in the skeleton because 70% of the body reserves of Mg are in the skeleton (Doyle 1979). In fact, the substitution of Ca by Mg makes the hydroxyapatite more compact and thus can have mechanical consequences for the skeleton (Ergun et al 2002). Similarly, K seems to play an important role in bone formation which has not been recognized until very recently.…”

Fabrication and biological evaluation of hydroxyapatite ceramics including bone minerals

“…6), 7) Magnesium (Mg) activates osteoblasts and osteoclasts, and not only promotes bone remodeling but also affects the nucleation and crystal growth of HAp. 8), 9) Several studies have demonstrated the varied properties of potassium (K) for the control of biochemical processes and the important role K plays in the apatite mineral nucleation process. 10), 11) As concerns anions, it is well known that fluor-ine (F) in the apatite phase is responsible for higher chemical and thermal stability.…”

Magnesium substitution in brushite cements for enhanced bone tissue regeneration

“…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].…”