Effects of clinical use and sterilization on surface topography and surface roughness of three commonly used types of orthodontic archwires.

Abstract

To evaluate the changes in surface topography and roughness of stainless steel (SS), nickel-titanium and beta-titanium (β-Ti) archwires after clinical use and sterilization. Thirty wires each of SS, nitinol, and β-Ti (3M Unitek) were tested in as received, as received and autoclaved, and clinically retrieved then autoclaved conditions. A sterilization protocol of 134°C for 18 min was performed using an autoclave. Surface topography of specimens from each subgroup was examined using an environmental scanning electron microscope (ESEM model Quanta 200, The Netherlands) at ×100, ×1000, and ×2500 magnifications. Surface roughness was measured using arithmetic mean roughness (Ra) values obtained from optical profilometric scanning (Taylor Hobson, Leicester, UK). Data were analyzed by one-way analysis of variance and Tukey's post-hoc procedures. Scanning electron microscope images revealed an increase in surface irregularities in SS and nitinol wires after clinical use. There was a significant increase in Ra values of SS orthodontic wires after intra-oral exposure (P = 0.0002). Surface roughness of SS wires increased significantly after clinical use. Autoclave sterilization did not affect considerably on surface characteristics of any archwire.