ELECTROCHEMICAL BEHAVIOUR OF TITANIUM IN AMMINE AND STANNOUS FLUORIDE AND CHLOREXIDINE 0.2% MOUTHWASHES

Titanium (Ti) is widely used in dentistry. Fluorides at acid pH could destabilize Ti oxide and make it susceptible to corrosion. The behaviour of IV grade machined Ti disks in 5 electrolytic solutions: Fusayama artificial saliva (Fas), ammine fluoride-stannous fluoride (Am-SnF2), 0.2% Chlorexidine (CHX) 0.20%, Fas with 20% Am-SnF2. and Fas with 20% CHX, was evaluated. Open circuit potential E-corr was determined by immersing Ti disks for 24 hours in an electrochemical cell containing the solutions, potential changes were measured until a stable value was obtained. Examination by Scanning Electronic Microscope and Energy Dispersive X-ray Analysis were then performed. One way ANOVA analysis showed a significant difference of E-corr values regarding the 5 solutions (p<0.001). The highest values were observed for Fas (-37.6 mV), intermediate for Am-SnF2 (-81 mV) and lowest for CHX (-87.6mV). SEM analysis of disks after polarization curve in CHX showed a marked localized corrosion, while the other solutions showed no considerable corrosive action on Ti surface. When considering corrosive potential range in oral cavity, Ti had an excellent behaviour on both antiseptics evaluated. The results obtained in this study will enable us to recommend the use of Am-SnF2 mouthwash for patients with dental implants.