Effect of plasma-sprayed hydroxyapatite coating on the osteoconductivity of commercially pure titanium implants

Formation of a calcium phosphate layer was studied on the surfaces of plasm a-sprayed hydroxyapatite (PSHA) and sandblasted commercially pure (cp) tita nium in simulated body fluid with ion concentrations similar to those of hu man blood plasma, The PSHA surface induced the formation of calcium phospha te surface layers, while the precipitation of calcium phosphate on sandblas ted cp titanium was not detected. Histologic evaluation of in vivo tests de monstrated that implants with a PSHA coating enabled the growth of bone tis sue into gaps with a depth of up to 1 mm without significant formation of i ntermediate fibrous tissue, In comparison to sandblasted cp titanium, impla nts with PSHA coating exhibited greater tolerance to unfavorable conditions during healing; such as gaps at the interface or primary instability of th e implant. In the case of good primary stability of the implant, filling of the gap with fibrous tissue was observed for sandblasted cp titanium impla nts over the greater part of the surface of gaps with a depth of 0.3 mm. Di rect contact of cp titanium implants with bone was achieved only when the p ress-fit implantation model was used.