الفهرس 
acknowledgmentOnly 14 pages are availabe for public view
 |  | from | 16 |  |  |
| | | from | 16 | | |
Abstract
One of the most important criteria in selection of the dental material specifically orthodontic alloys is the resistance towards the corrosion. Corrosion of metals in oral cavity leads to leaching of ions in the saliva that may cause a wide range of adverse effects starting ftom burring sensation ending with cytotoxic and carcinogenic effects.
In this study the corrosion resistance of four different orthodontic arch wire alloys (Stainless steel, NiTi, Epoxy coated NiTi and Titanium) and the effect of intraoral usage on their corrosion susceptibility have been investigated using the anodic polarization test which is one of the most common electrochemical tests. The breakdown potential and the critical current density were the parameters in evaluation of the corrosion susceptibility of the different four alloys. The four types of arch wire
alloys were subjected to the anodic polarization tests before being used intraorally (as received) and after being used intraorally for one month (retrieved).
Scanning electron-microscope was used for a topographical scanning of the surfaces of the different specimens for a qualitative analysis.
At the end the followine; has been concluded:
1- Stainless steel orthodontic arch wire alloy showed passivation (formation of a passive film which provide a resistant towards the corrosion) when it used intraorally.
2- However as received NiTi orthodontic arch wire alloy was more corrosion.
Author:
Hany Abdel Hameed El-Khallaf