THE EFFECT OF BIOLOGICAL ENVIRONMENT ON THE SURFACE OF TITANIUM AND PLASMA-SPRAYED LAYER OF HYDROXYLAPATITE

The solubility of titanium samples with different surface coatings, i. e. hydroxylapatite (HA) powders, a two-layer coating of ZrO5+ HA on a titanium substrate in solution and of tooth implants after long-term f unctioning in the human organism, was studied. A minimum difference in solubility of titanium samples with different surface finishes (polis hed or grit blasted) was established. For the HA powders and coatings, the lowest solubility was observed with a coarse-grained HA-B powder and a coating made of that powder. Clinical tests of tooth implants af ter long implantation times were performed. A titanium implant (implan tation 12 y), a titanium implant with a two-layer coating of ZrO5+HA-A (implantation time 4 y) and a titanium implant with a two-layer coati ng of (Al5O3 + 3% TiO2) + HA-A (implantation time 6 y) were studied. T he results show that the titanium surface and HA-A layers were dissolv ed. Nevertheless, after 6 y implantation, total removal of HA-A coatin g from that part of implant set into the bone, was not observed.