Osteoclastic resorption of calcium phosphate ceramics with different hydroxyapatite/beta-tricalcium phosphate ratios.
To study the influence of calcium phosphate ceramic solubility on osteoclastic resorption, neonatal rabbit bone cells were cultured for 2 days on hydroxyapatite (HA), beta-tricalcium phosphate (beta-TCP) and two types of biphasic calcium phosphate (BCP) with HA/beta-TCP ratios of 25/75 and 75/25. Solubility was regulated by varying the ratio of less-soluble HA and more-soluble beta-TCP. After removal of stromal cells by pronase E treatment, ceramic surfaces were observed by scanning electron microscopy. Osteoclasts resorbed BCP most extensively, with an HA/beta-TCP ratio of 25/75, producing typical lobulated, zig-zag track-like resorption lacunae. On pure beta-TCP, which had the highest solubility in acid, osteoclasts formed smaller discontinuous island-like lacunae. The resorption pattern may have been modified by the large number of calcium ions released into the acidic microenvironment at the osteoclast-ceramic interface. No resorption lacunae were found on the other specimens. The extent of osteoclastic resorption of calcium phosphate ceramics might, to a certain degree, be proportional to solubility, although this was not the case when solubility was very high. It would appear that ceramic solubility influences osteoclast resorption activity.
Yamada
S
S
UPRES 2159, Faculté de Chirurgie Dentaire, Nantes, France.
Heymann
D
D
Bouler
J M
JM
Daculsi
G
G
D000818:Animals; D000831:Animals, Newborn; D001672:Biocompatible Materials / Q000378:metabolism; D001862:Bone Resorption / Q000378:metabolism*; D002130:Calcium Phosphates / Q000378:metabolism*; D002478:Cells, Cultured; D002516:Ceramics / Q000378:metabolism*; D017886:Durapatite / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D010010:Osteoclasts / Q000378:metabolism* / Q000648:ultrastructure; D011817:Rabbits; D012995:Solubility; D013499:Surface Properties
D001672:Biocompatible Materials; D002130:Calcium Phosphates; C485817:beta-tricalcium phosphate; D017886:Durapatite; C018392:tricalcium phosphate