Investigation of physicochemical properties of clinically retrieved TriTanium orthodontic archwires


Investigation of physicochemical properties of clinically retrieved TriTanium orthodontic archwires


A. Stoyanova-Ivanova1, V. Petrova1*, I. Ilievska1, M. Gueorgieva2, V. Petrov2, L. Andreeva2, A. Zaleski3, V. Mikli4
1G. Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia, Bulgaria 1*Faculty of Chemical Technology, University of Chemical Technology and Metallurgy, Sofia, Bulgaria
2Faculty of Dental Medicine, Medical University of Sofia, Sofia, Bulgaria
3Institute of Low Temperatures and Structure Research, Polish Academy of Science, Wroclaw, Poland
4Institute of Materials and Environmental Technology, Tallinn University of Technology, Estonia


One of the basic requirements for an orthodontic archwire is to achieve biologically tolerable forces, which is important when choosing a suitable archwire for a certain stage of orthodontic treatment. The orthodontic archwire TriTanium is made out of NiTi alloy and has three distinct thermally activated force regions which release the cor¬rect force in the anterior, premolar, and molar arch-regions in order to efficiently level, align and torque. This work aims to identify the chemical composition, structure and thermal behavior of clinically retrieved (up to 6 and more than 8 weeks) TriTanium (0.41×0.56 mm2) archwires. The studies were conducted in the three regions of elasticity: anterior – including the four incisions teeth, middle teeth – including the canine teeth and the premolars and the posterior e.g. the molars. The following methods are used: XRD, EDX, SEM and DSC. The EDX analysis shows that Ni and Ti are the main elements in the composition of the examined archwires and their ratio is kept 1:1 during treatment. The room temperature XRD patterns show typical peaks for a Ni-Ti alloy with austenite type structure. SEM micrographs show different morphology in the three zones of the investigated archwires. The DSC measurements were conducted in the –50 °C to +50 °C temperature range and revealed three phase transitions (austenite, martensite and R-phase) in the three zones. Тhe wearing of the archwires in the patients’ mouth alters the thermal phase transitions in the three investigated regions of TriTanium archwires.
Key words: TriTanium, clinically retrieved, Ni-Ti orthodontic archwires, XRD, DSC