Properties And Microstructure Of Root Canal Files Coated With TiZrON Films

Stainless steel and nickel titanium alloy are commonly used in root canal therapy instrument.In their uses,however,due to the precipitation of chromium and nickel ions,it is easy to cause allergic reactions,and even to cause cancer.One of the effective methods to avoid nickel ions and chromium ions is preparing a protective film overlaying the surface of root canal file.This present work is to deposit Ti Zr NO films on nickel titanium root canal file and stainless steel root canal file surfaces using multi arc ion plating technology.With Ti Zr alloy cathodic targets,the deposition experiments of the TiZrON films are performed by changing the substrate bias,the oxygen flow rate,nitrogen flow rate.Scanning electron microscope(SEM)and energy spectrum analysis are used to observe the surface microstructure morphology and to measure the surface composition of the as-deposited TiZrON films.X-ray diffraction test are used in the analysis of the phase composition of the as-deposited TiZrON films.With the help of the Parstat 2273 electrochemical test system,electrochemical corrosion performance analysis for the films is completed.The simulated clinical preparation of root canal tests are also carried out to compare the practical effects of root canal file overlaid by different TiZrON films.The research results show that for Ni Ti root canal files,under the premise of keeping the original elastic performance of the Ni Ti alloy root canal files,TiZrON films with moderate oxygen content is beneficial to enhance abrasion resistance.While,low oxygen content in the TiZrON films can be beneficial to enhance corrosion resistance.In the consideration of both corrosion resistance and wear resistance,the optimized deposition process includes negative bias of-100 ~-150 V,oxygen flow of 13 sccm,deposition time no more than 20 minutes and the deposition temperature not exceeding 230 ?.For stainless steel root canal files,the one overlaid by TiZrON film with lower oxygen content deposited at-100 V bias shows the best abrasion resistance and the one overlaid by TiZrON film with moderate oxygen content deposited at-150 V bias shows the best abrasion resistance.At the same time,compared with the other TiZrON films deposited by different processes,these two kinds of TiZrON films also show stronger corrosion resistance.Above all,the overlaying TiZrON films with optimal abrasion resistance and corrosion resistance can be prepared on nickel titanium root canal file and stainless steel root canal file surfaces by choosing appropriate multi arc ion plating deposition process and the cathode arc source target.The effective protection of root canal file then can be achieved.