Physicochemical Research of Clinically Retrieved CU-NI-TI Orthodontic Archwires

Abstract

In modern orthodontics, thermally activated archwires are used more widely in clinical practice, because they have unique properties like superelasticity and bio-compatibility. The aim of the present study was to characterize commercial 35° C Cu-NiTi archwires in terms of their phase transition behavior, chemical composition, surface topography properties after clinical usage, as well as the influence of the autoclaving process. Materials and methods. 35° C Thermo-Active Copper NiTi (CuNiTi) of ORMCO, Glendora, CA, USA (as-received, as-received autoclaved and clinically retrieved) with rectangular cross-section and dimension 0.016x0.022 inch, were investigated. The physicochemical research was conducted via Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDX) and X-ray Diffraction Analysis (XRD). The autoclaving was done in Runyes model B autoclave. Results. The DSC results revealed the austenite start (9.8° C; 26.47° C) and austenite finish (28° C; 31.74° C) temperatures for the as-received and autoclaved archwires respectively. For clinically retrieved samples the austenite finish temperature (Af) is around 27° C. The XRD patterns of the as-received and clinically retrieved samples show almost identical diffraction patterns. Rough surface of the CuNiTi alloy was revealed by the SEM analysis. Autoclaving process seems to have no effects on archwires’ structure and chemical composition. Chemical content of the investigated as-received CuNiTi are Ni, Ti and Cu: 47.07 wt% and 46.81 wt% and 6.11 wt%, respectively. The autoclaving process seems to have little influence on the transition temperature. The results from our study showed little difference (~7 °C) in the finish transition temperatures (Af), compared to the manufacturer’s claim. No intermediate R phase was detected by DSC. Conclusion. A good knowledge of the structural changes that occur in CuNiTi alloys in the oral cavity is useful for the orthodontists in order to optimize orthodontic treatment.

Multi-Force Bio-Active™ Archwires and Various Contemporary NiTi Multi-Force Archwires: Properties and Characteristics—A Review

“…It is important that independent studies be conducted to verify the information provided by the manufacturer, as manufacturers generally do not openly discuss their proprietary manufacturing techniques. To address this, we carried out studies [ 38 , 39 , 40 , 68 , 69 ], where the mechanical and thermal properties of the Bio-active, along with the TriTanium archwires, were studied and compared. Part of these studies also includes physicochemical characterization [ 38 ], which involves tests such as X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and laser-induced breakdown spectroscopy (LIBS).…”

“…It shows that the Bio-active archwire contains trace amounts (0.3 wt%) of Fe and Cr [ 38 , 68 ], while the TriTanium archwires do not contain any elements other than Ti and Ni [ 68 ]. The presence of Fe and Cr should be taken into account when treating patients allergic to those elements.…”

“…They can be classified into the group of martensite-active wires (heat-activated) because the manufacturers set the Af to be above room temperature and close to the temperature of the oral cavity. In contrast, the TriTanium archwires show different thermal transition temperatures for the austenitic, martensitic, and R phases between the as-received and clinically retrieved TriTanium archwires [ 68 ]. As their clinical use time increases, an Af temperature difference in all regions of the archwire, especially in the premolar region, can be seen at ~8 °C.…”

Impact of Beam Deflection Geometry on the Surface Architecture and Mechanical Properties of Electron-Beam-Modified TC4 Titanium Alloy

“…Titanium-based alloys have been widely used for the production of orthopedic implants and prostheses [1][2][3], as well as for orthodontic archwires and dental instruments [4,5], due to their significant number of exceptional properties (good corrosion resistance, better biocompatibility, and higher specific strength). However, when placing implants in the human body, a number of adverse reactions may occur (fracture of the implant, deterioration of adhesion, release of metal ions, etc.…”