Interaction of acid and alkali treated titanium with dynamic simulated body environment

Interaction of acid and acid+alkali treated titanium samples with simulated body fluid was studied. In case of alkali treated titanium, the dynamic arrangement of the test enabled the detection of primary calcium and phosphate ion adsorption from the solution and later apatite crystal growth (XRD). The induction time for crystal growth was 24.2±0.3 h. On acid-only treated titanium no crystal growth was detected. The calcium phosphate adsorption layer formed on the acid treated samples was detectable by XPS only, however it differed from that one formed on the acid+alkali treated samples. The adsorption layer formed on the acid+alkali treated samples contained larger amount of calcium, especially in the shortest exposure times. Charging of the apatite crystallites during the XPS measurement enabled the determination their Ca/P ratio separately from Ca/P ratio of the adsorption layers. XPS and EDS analyses indicated that the spherulitic crystallites consisted of carbonated hydroxyapatite with the Ca/P ratio close to that one of the stoichiometric hydroxyapatite. It is proposed that the adsorption layer formed spontaneously and immediately on the acid+alkali treated titanium can provide an ideal interface between the metal implant and the apatite cement line, the first structure formed by osteoblast cells during the formation of the new bone on foreign surfaces. This revised version was published online in August 2006 with corrections to the Cover Date.