The Role of Nicotine in the Corrosive Behavior of a Ti-6Al-4V Dental Implant.

BACKGROUND: Metals react chemically/electrochemically in electrolytic solutions, such as that present in the oral cavity, which leads to corrosion of metal dental implants. Corrosion can increase the failure rate of dental implants. PURPOSE: This study evaluated the corrosion behavior of nicotine on Ti-6Al-4V under physiological conditions. It was hypothesized that nicotine in artificial saliva would have an adverse effect on the corrosion of Ti-6Al-4V. METHODS: Ti-6Al-4V discs were electrochemically analyzed using a three-electrode electrochemical cell. The disks were immersed in an electrolytic artificial saliva with varying pH (3.0 and 6.5) and nicotine concentration (control, 1 mg/mL, 5 mg/mL, and 20 mg/mL). Open circuit potential, cyclic polarization, and electrochemical impedance spectroscopy (EIS) tests were conducted. RESULTS: Electrochemical parameters indicated that the presence of nicotine significantly reduced (p < .05) the corrosion rate. For example, there was a decrease in corrosion current density from 2.94 x 10(-3) muA/cm(2) to 1.43 x 10(-3) muA/cm(2) in control compared with 20 mg/mL nicotine at pH 6.5. EIS results exhibited an unexpected trend in that the presence of nicotine decreased polarization resistance. This suggested a decrease in passive film growth. CONCLUSIONS: At certain concentrations, nicotine inhibits local corrosion; however, it also prevents the formation of a protective oxide film.