Surface chemistry analysis of ultraviolet-treated titanium

Abstract

OBJECTIVES: Titanium (Ti) surface chemistry is known to strongly influence the interactions between implant surface and surrounding environment. A clean Ti surface is hydrophilic and contains higher level of Ti and oxygen (O) and lower level of hydrocarbons (C). This study compares the outermost surface chemistry of Ti with smooth and rough surface topographies with and without ultraviolet (UV) treatment. METHODS: Ti discs (8mm diameter) were prepared with 4 different surface treatments: polished, polished+UV, acid-etched, and acid-etched+UV. Polished surfaces were produced by abrasive silicon carbide paper grinding. Acid-etching was done with 67% sulfuric acid at 120ºC for 75 seconds. UV-treatment was performed by 15W Germicidal UVC, 254nm, for a period up to 48 hours. Surface morphology and roughness (Ra) were examined in the 4 groups using Scanning Electron Microscope (SEM) and Surtronic 3+, respectively. Titanium samples were immediately analyzed after preparation by X-ray photoelectron spectroscopy (XPS). The relative atomic concentrations of Ti, O, and C in the 4 groups (n=5) detected by XPS were statistically analyzed by ANOVA. RESULTS: Polished and polished+UV Ti showed a smooth surface topography with Ra values of 0.3±0.1µm and 0.2±0.1µm, respectively. Acid-etched and acid-etched+UV Ti showed micro-roughness consisting of sharp ridges and pits with Ra values of 1.9±0.8µm and 1.5±0.3µm, respectively. The concentrations of Ti, O and C were statistically significantly affected by surface roughness and UV-treatment (P<0.05). The smooth surfaces acquired relatively higher Ti and O and lower C concentrations compared to rough surfaces. UV-treatment substantially decreased C contamination and increased the Ti and O concentrations in the Acid-etched groups (P<0.05). CONCLUSIONS: UV-treatment may be an effective way to produce less carbon clean Ti surface especially after roughening the Ti surface by acid-etching.