INTERFACIAL PHENOMENA - AN IN-VITRO STUDY OF THE EFFECT OF CALCIUM-PHOSPHATE (CA-P) CERAMIC ON BONE-FORMATION

In previous studies we developed a RF magnetron sputter technique for the production of thin Ca-P coatings. With this technique coatings can be produced that vary in Ca/P ratio as well as in structural appearan ce. The aim of this investigation was to obtain more understanding of the biological behavior of these coatings by way of in vitro experimen ts. The effect of noncoated titanium (Ti) and three different Ca-P-spu ttered surfaces on the proliferation and differentiation (morphology a nd matrix production) of osteoblast-like cells was studied. Proliferat ion was determined using counting procedures; morphology was studied b y scanning electron microscopy (SEM) and transmission electron microsc opy (TEM). Fluorescent markers and energy dispersive X-ra) microanalys is (EDX) were used to obtain quantitative and compositional informatio n about the resultant calcified extracellular matrix (ECM). Results de monstrated that proliferation of the osteoblast-like cells was signifi cantly (p < 0.05) higher on noncoated than on Ca-P-coated samples. On the other hand, more mineralized ECM was formed on the coated surfaces . In addition, TEM confirmed that the cells on the coated substrates w ere surrounded by ECM with collagen fibers embedded in crystallized, n eedle-shaped structures. On the basis of these findings, we concluded that: (1) the investigated Ca-P sputter coatings possess the capacity to activate the differentiation and expression of osteogenic cells, an d (2) bone formation proceeds faster on Ca-P surfaces than on Ti subst rates. Further, this bone-inductive effect appeared to be dependent on the Ca-P ratio of the deposited coatings. (C) 1998 John Wiley & Sons, Inc.