Characterisation of NiTi Orthodontic Archwires Surface after the Simulation of Mechanical Loading in CACO2-2 Cell Culture

Abstract

Nickel-titanium (NiTi) orthodontic archwires are crucial in the initial stages of orthodontic therapy when the movement of teeth and deflection of the archwire are the largest. Their great mechanical properties come with their main disadvantage—the leakage of nickel. Various in vitro studies measured nickel leakage from archwires that were only immersed in the medium with little or minimal simulation of all stress and deflection forces that affect them. This study aims to overcome that by simulating deflection forces that those archwires are exposed to inside the mouth of a patient. NiTi orthodontic archwires were immersed in CACO2-2 cell culture medium and then immediately loaded while using a simulator of multiaxial stress for 24 h. After the experiment, the surface of the NiTi orthodontic archwires were analysed while using scanning electron microscopy (SEM) and auger electron spectroscopy (AES). The observations showed significant microstructural and compositional changes within the first 51 nm thickness of the archwire surface. Furthermore, the released nickel and titanium concentrations in the CACO2-2 cell culture medium were measured while using Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). It was found out that the level of released nickel ions was 1.310 µg/L, which can be assigned as statistically significant results. These data represent the first mention of the already detectable release of Ni ions after 24 h during the simulation of mechanical loading in the CACO2-2 cell culture medium, which is important for clinical orthodontic praxis.

Preparation and Characterization of NiTi/PVA Nanofibers by Electrospinning

“…The high amount of Titanium oxide (TiO 2 ) is attributed to the impure Argon atmosphere (air leaking) of the utilized furnace during the sintering process. Since Ti is more active as compared to Ni [24], when Ti is in contact with oxygen, instantly TiO 2 forms on the surface of the alloy [25,26]. It is composed of TiO 2 as the free enthalpy of formation of TiO 2 is negative, it exceeds the enthalpy of the formation of nickel oxides [25].…”

“…Since Ti is more active as compared to Ni [24], when Ti is in contact with oxygen, instantly TiO 2 forms on the surface of the alloy [25,26]. It is composed of TiO 2 as the free enthalpy of formation of TiO 2 is negative, it exceeds the enthalpy of the formation of nickel oxides [25]. TiO 2 protects the alloy from corrosion, and it creates a physical and mechanical barrier for the oxidation of nickel [25,27].…”

“…It is composed of TiO 2 as the free enthalpy of formation of TiO 2 is negative, it exceeds the enthalpy of the formation of nickel oxides [25]. TiO 2 protects the alloy from corrosion, and it creates a physical and mechanical barrier for the oxidation of nickel [25,27]. On the other hand, the XRD pattern of NiTi nanoparticles (Figure 3) major intermetallic phases are NiTi, Ni 3 Ti, and Ti 2 Ni, which are the stable phases of NiTi alloy [28].…”

Ultrasonic Sensors-Assisted Corrosion Studies on Surface Coated AlSi9Cu3 Alloy Die Castings

“…The acrylic paint ED coatings exhibited higher resistance in AC and lowered resistance in DC; on the other hand, other coatings exhibited lower resistance in AC and higher resistance in DC. In future work, advanced digital-driven transformation technologies (Industry X.0), including artificial intelligence approaches, shall be deployed for overcoming the challenges faced due to corrosion and related issues [25][26][27][28][29][30][31][32][33][34][35][36], thereby improving the quality of the coating longevity. The salt spray test results confirm that 3-coat polyester with epoxy primer coated sample exhibits an oxide film on the surface that temporarily resist the local corrosion attack.…”

On the design strategies for SMA-based morphing actuators: state of the art and common practices applied to a fascinating case study

“…Au-based biomedical [12][13][14][15] Ni-Ti-based medical instruments (medical implants, 16 stent, 17 orthodontics, 18 surgery, 19 rehabilitation devices 20 ), Aerospace devices (rotary actuators, 21 solar sail, 22 morphing wing 23 ) Cu-based 24 pipe couplings, 25 hydraulic fittings, 26 mechanical dampers, 27,28 energy dissipation devices, 29 textiles 30 Fe-based 31 fishplates for crane rails, 32 pipe couplings, 25 civil structures 33 (concrete reinforcement, 34 damping, 35 pre-stressing elements 36 ) aerodynamic devices. In particular, it can be noted that most of the devices are dealing with aircraft components, with specific regard to wings, and focusing on design, fabrication, testing and modeling aspects.…”