Osteoclastic resorption of apatite formed on apatite‐ and wollastonite‐containing glass‐ceramic by a simulated body fluid

Abstract

We immersed mirror‐polished apatite‐ and wollastonite‐containing glass‐ceramic (A‐W GC) disks in a simulated body fluid (SBF) for 5 days to form bonelike apatite on their surface. Neonatal rabbit bone cells were cultured on these on plain A‐W GC disks for 10, 24, and 48 h. We observed the substrates by scanning electron microscopy after treating them with pronase E plus EDTA to remove all cells except osteoclasts. Osteoclasts with a non‐motile appearance formed no lacunae on the plain A‐W GC, whereas on the bonelike apatite formed on A‐W GC by the SBF, actively moving osteoclasts made many tracklike resorption lacunae. These were evident even after 10 h of culture and became more extensive after longer culture periods. The bonelike apatite was therefore a more suitable medium than plain A‐W GC for maintaining osteoclast activity. This study demonstrated in vitro osteoclastic resorption of bonelike apatite formed on A‐W GC by an SBF. It suggests that the apatite layer, through which a surface‐active ceramic bonds to bone in vivo, can be resorbed by osteoclasts and subjected to bone remodeling. © 1994 John Wiley & Sons, Inc.