Corrosion Behavior of Two cp Titanium Dental Implants Connected by Cobalt Chromium Metal Superstructure in Artificial Saliva and the Influence of Immersion Time

摘要

In this study, we invistegate the effect of connecting two similar cp titanium implant fixtures and theimmersion time on the electrochemical behavior of these implant fixture system using Straumann(Institute Straumann, Basel, Switzerland) coupled with cobalt chrome framework in artificial saliva.The two implant fixtures had the same composition, diameter, length and surface treatment. Thecorrosion measurements were carried out using open-circuit potential, cyclic potentiodynamicpolarization, electrochemical impedance spectroscopy, and chronoamperometric current-timemeasurements. The surface morphology and the elements analysis for the corroded samples wereinvestigated using scanning electron microscope and energy dispersive X-ray analyzer. The effect ofprolonging the period of immersion time on the corrosion of the couple in the saliva from 1 to 24 andfurther to 48 h before measurements was also reported. It has been found that the tested implant systemhas high passivation against corrosion and the intensity of its uniform corrosion increases withincreasing the immersion time in the artificial saliva from 1 to 24 and further to 48 h. This wasconfirmed by the remarkable increase in the values of corrosion current and the decrease in thepolarization resistance values over time. On the other hand, the severity of pitting corrosion wasnoticed to decrease with time, which was indicated via decreasing the area of hysteresis loop andshifting the values of the protection potential to more positive direction.