Purpose: Evaluation of pharmaceutical compounds (Ciprofloxacin,  Clotrimazole, Chitosan)  and prepared plant extracts (Clove, Thyme) as corrosion inhibitors for Cu Ni Ti orthodontic arch wire, in acidulated phosphate fluoride solution (APF) (0.5 % NaF + 0.17 % H₃Po₄) adjusted to pH of 3.5. simulating commercial fluoride containing products.
Materials and Methods:Forcorrosion testing, eighty specimens (10 mm in length) were investigated by pontiodynamic method (five specimens for 0.5% NaF (control  group) and five specimens for  different corrosion inhibitors ). For Surface roughness and Scanning electron microscope examination, a representative samples from each group were investigated. ANOVA and Tukey tests were used to compare between groups at significant level (p ≤ 0.05).
Results: Significant differences were found in means of corrosion resistance (I_corr ), between different corrosion inhibitors (ciprofloxacin, clotrimazole, chitosan, clove, thyme) and control  group.
Conclusion: The corrosion rate was significantly decreased by adding different corrosion inhibitors, indicating the formation of protective layer  on the wire surface.