Comparison between Corrosion of Stainless Steel Hand k-file and Nickel-Titanium Rotary Instrument following Immersion in 5.25% NaOCL Irrigation Solution: An In Vitro Study

The study was aimed to compare the corrosion of stainless-steel hand K-file and Nickel-titanium rotary instrument following immersion in 5.25% NaOCL irrigation solution, in vitro. A total of 20 new Nickel-titanium (NiTi) rotary files and 20 stainless steel (K file) was selected and immersed in 5.25% NaOCL irrigation solution. All files were subjected to the corrosion test: Record the open circuit potential (OCP) for 1 h on a strip chart with high impedance. The strip chart recording for each file was classified into a stability score: (i) stable, (ii) unstable, or (iii) erratic. The percentage of OCP was measured by a potentiostat and a standard calomel electrode reference. The frequencies of visually observed corrosion were further investigated by scanning electron microscope (SEM). The results of the present study confirmed that stainless steel file showed greater corrosion rate than that of NiTi files. Additionally, both files had pitting and crevice corrosion, as seen by scanning electron microscopy (SEM) analysis. However, NiTi files demonstrated a lower rate of corrosion than stainless steel files. In conclusion, NiTi files showed greater corrosion resistance than that of stainless-steel files.