Interaction of a plasma-sprayed hydroxyapatite coating in contact with human osteoblasts and culture medium

The loss of calcium from plasma-sprayed calcium phosphate ceramics (CPCs) o n bioinert metal substrate (Ti-6A1-4V) immersed in cell culture medium with or without human osteoblast culture was measured. The ceramics were a CPC and a duplex system composed of a CPC layer on an alumina coating. The diss olution of calcium compounds was monitored by measuring the calcium leaked from the coatings into the culture medium in 15 days. Calcium was measured by flame photometry. The surfaces of the ceramics exposed to the culture me dium and in contact with osteoblasts were analysed by X-ray diffraction (XR D). The dissolution process occurred in the first 6 days of contact, but th e calcium released into the culture medium was only a small fraction of the calcium content of the coatings. The presence or absence of osteoblasts on the surface of the ceramics did not make significant difference for the ca lcium release. The XRD spectra of the ceramics before and after immersion a nd in contact with cells did not show a significant change in the compounds of the coatings. (C) 1999 John Wiley & Sons, Inc. J Biomed Mater Res, 46, 331-336, 1999.