INFLUENCE OF SURFACE TREATMENTS DEVELOPED FOR ORAL IMPLANTS ON THE PHYSICAL AND BIOLOGICAL PROPERTIES OF TITANIUM .1. SURFACE CHARACTERIZATION

We present an investigation of the physico-chemical surface properties of commercially pure titanium coverslips which were submitted to vari ous treatments designed to optimize their topography in view of applic ation in oral implantology. The surface microroughness, chemical compo sition and water wettability were analyzed on titanium coverslips prep ared by mechanical polishing, acid attack in HCl/H2SO4, after mechanic al polishing or sandblasting, and titanium plasma-spray. The chemical composition has been measured by Auger electron spectroscopy. The trea tments have no major influence on the surface chemical composition and all the samples display a composition approaching that of TiO, with m inor amounts of carbon, sulfur, silicon and calcium as impurities. The roughness has been measured by scanning force microscopy on an area o f 20 mu m x 20 mu m on each sample. Polished titanium is smooth (peak- to-valley roughness 81 nm), whereas the acid-attacked surfaces exhibit a micro-roughness in the pm range (2100 nm for polished and acid atta cked; 3600 nm for sandblasted and acid attacked) which is quite reprod ucible over large areas of the sample. The acid attacked samples prese nt a subsurface layer which contains hydrogen below the native passiva ting oxide layer. Water wettability measurement shows that all surface s are hydrophobic with a slightly higher contact angle for the acid at tacked surfaces. The different treatments analyzed in this study essen tially influence the surface roughness by preserving the chemical comp osition and the wettability properties of titanium native oxide surfac e layer.