Corrosion behavior of surface modifications on titanium dental implant. In situ bacteria monitoring by electrochemical techniques

Abstract

The effects of surface modifications and bacteria on the corrosion behavior of titanium have been studied. Five surface modifications were analyzed: two acid etchings (op V, op N), acid etching1anodic oxidation (op NT), sandblasting1acid etching (SLA), and machined surfaces (mach). The corrosion behavior of the surface modifications was evaluated by following the standard ANSI/AAMI/ISO 10993-15:2000. Cyclic potentiodynamic and potentiostatic anodic polarization tests and ion release by ICP-OES after immersion for 7 days in 0.9% NaCl were carried out. Microbiologically induced corrosion (MIC) of low and high roughness (mach, op V) was assessed in situ by electrochemical techniques. Streptococcus mutans bacteria were resuspended in PBS at a concentration of 3 3 108 bacteria mL21 and maintained at 378C. MIC was measured through the open circuit potential, Eoc, and electrochemical impedance spectroscopy from 2 to28 days. Potentiodynamic curves showed the typical passive behavior for all the surface modifications. The titanium ion release after immersion was below 3 ppb. In situ bacteria monitoring showed the decrease in E oc from 20.065 (SD 0.067) V vs. Ag/AgCl in mach and 20.115 (SD 0.084) V vs. Ag/AgCl in op V, to 20.333 (SD 0.147) V vs. Ag/AgCl in mach and 20.263 (SD 0.005) V vs. Ag/AgCl in op V, after 2 and 28 days, respectively. A reduction of the oxide film resistance, especially in op V (54 MX cm 2 and 6 MX cm 2 , after 2 and 28 days, respectively) could be seen. Streptococcus mutans negatively affected the corrosion resistance of titanium