Abstract

Introduction: The present work aims to study the toxicity of orthodontic archwires based on Nickel-Titanium and to evaluate the protective effect of different types of extracts of Celtis australis and Syzygium aromaticum, considered as natural corrosion inhibitors, on Tetrahymena thermophila and Tetrahymena pyriformis. Methods: Tetrahymena thermophila and Tetrahymena pyriformis were cultured in artificial saliva previously incubated in the presence of NiTi or CuNiTi wires with or without the addition of different types of plant extracts (extract, hydrosols, essential oils). The effect of wires and plant extracts on Tetrahymena was evaluated after 2, 4 and 7 days of growth, by the protozoan viability test and the microscopic observation of the shape. Results: For the two Tetrahymena species, NiTi and CuNiTi cause a decrease in Tetrahymena growth by about 50%.