ABSTRACT
Aim: 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. Settings and Design: 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. Materials and Methods: 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). Statistical Analysis: Data were analyzed by one‑way analysis of variance and Tukey’s post‑hoc procedures. Results: 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). Conclusion: Surface roughness of SS wires increased significantly after clinical use. Autoclave sterilization did not affect considerably on surface characteristics of any archwire.
ABSTRACT
Introduction: Elastomeric ligatures reduce chairside time but increase friction. Polymeric coatings and 45° angulations have been introduced to the ligature modules to combat its disadvantages and reduce friction. This in vitro study compared the frictional characteristics of six different types of the most commonly used elastomeric modules. Materials and Methods: Thecoefficient of friction for six ligation methods: the non-coated Mini Stix† and coated Super Slick Mini Stix™ (TP Orthodontics), 45° angulated but non-coated Alastik Easy-To-Tie™ (3M Unitek) elastomerics and non-angulated non-coated Alastik QuiK-StiK * , 0.110'- and 0.120'-diameter elastomerics™ (Reliance Orthodontics) were measured in dry conditions utilizing a jig according to the protocol of Tidy. Results: A significant difference was observed between the various types of elastomeric ligatures (P<.01). Among the six types of elastomeric ligatures, the 45° angulated elastomeric ligatures produced the least friction, followed by the coated Super Slick† elastomers. No difference in the friction was noted when the diameter of the elastomeric ligatures was varied. Conclusions: Polymeric surface coatings and introduction of angulations into elastomeric ligatures reduce the friction during sliding; however, the diameter of the ligature made no difference to sliding friction.