Osseointegration of composite calcium phosphate bioceramics

The resistance of macroporous calcium phosphate ceramics to compressive str ength generally is low and depends on, among other factors, porosity percen tage and pore size. A compromise always is adopted between high porosity, r equired for a good integration, and mechanical strength, which increases wi th material density. We improved the strength of macroporous calcium phosph ate ceramics of interconnected porosity by filling the pores with a highly soluble, self-setting calcium phosphate cement made of TCP and DCPD. Cylind ers of the resulting material were implanted in sheep condyles and subjecte d to histological analysis after 20, 60, and 120 days, Microradiographs wer e made of the histological sections. The control material consisted of cera mic that had not been loaded with cement. Progressive ingrowth of hone into the ceramic pores occurred as the cement was degraded during the first imp lantation period. Marked degradation of the cement was apparent after 2 mon ths, with fragmentation of the cement in most of the pores and the presence of bone tissue between the fragments. All the cement had been replaced by bone after 4 months. Some fragments of cement still were embedded in the ne wly formed bone. There was no significant difference between the integratio n of loaded and nonloaded ceramics. Filling the macroporous ceramic pores w ith a calcium phosphate cement significantly improved the mechanical streng th of these ceramics without modifying their integration in the healing bon e. (C) 2000 John Wiley & Sons, Inc.