Ultrastructural study of mineralization of a strontium-containing hydroxyapatite (Sr-HA) cement in vivo.
The purpose of this study was to investigate the mineralization leading to osseointegration of strontium-containing hydroxyapatite (Sr-HA) bioactive bone cement injected into cancellous bone in vivo. Sr-HA cement was injected into the ilium of rabbits for 1, 3, and 6 months. The bone mineralization area was found to be largest at 3 months, then at 1 month, and smallest at 6 months (p < 0.01) measured with tetracycline labeling. Osseointegration of Sr-HA cement was achieved at 3 months as observed by scanning electron microscopy. A high calcium and phosphorus area was observed at the interface of bone-Sr-HA cement determined by energy-dispersive X-ray analysis. Transmission electron microscopy gave evidence of the mechanism of bone formation. Dissolution of Sr-HA into debris by the bone remodeling process was thought to increase the concentration of calcium and phosphorus at the interface of bone-Sr-HA cement and stimulate bone formation. Crystalline Sr-HA formed an amorphous layer and dissolved into the surrounding solution, then apatite crystallites were precipitated and formed new bone at 3 months. This young bone then becomes mature bone, which bonds tightly to the Sr-HA cement with collagen fibers inserted perpendicularly after 6 months.
Wong
C T
CT
Department of Orthopaedic Surgery, Faculty of Medicine, The University of Hong Kong, Hong Kong SAR.
Chen
Q Z
QZ
Lu
W W
WW
Leong
J C Y
JC
Chan
W K
WK
Cheung
K M C
KM
Luk
K D K
KD
D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000378:metabolism; D001843:Bone Cements / Q000737:chemistry* / Q000378:metabolism; D002113:Calcification, Physiologic / Q000502:physiology*; D006882:Hydroxyapatites / Q000737:chemistry* / Q000378:metabolism; D007085:Ilium / Q000502:physiology / Q000648:ultrastructure; D008422:Materials Testing; D016348:Osseointegration / Q000502:physiology; D011817:Rabbits; D013324:Strontium / Q000737:chemistry* / Q000378:metabolism
D001672:Biocompatible Materials; D001843:Bone Cements; D006882:Hydroxyapatites; D013324:Strontium