Characterization and comparison of as received and clinically retrieved Bio-active™ orthodontic archwires

Abstract

This study aimed to characterize and compare the latest generation multi-force Bio-active™ orthodontic archwires to determine if there is a change in their physicochemical and mechanical properties during orthodontic treatment. The physicochemical characterization of the archwires was done by X-ray diffraction (XRD), scanning electron microscopy, energy-dispersive X-ray spectroscopy and laser-induced breakdown spectroscopy. A modified dynamic nanoindentation method with depth control was used to determine the mechanical properties. Statistical analysis was done by one-way analysis of variance (ANOVA). The XRD analysis showed that all investigated archwires are made of Ni-Ti alloy with an austenite crystal structure. The surface roughness of the Bio-active™ wires decreases after clinical use. The elemental composition analysis showed that the weight percentage of nickel and titanium is approximately 55 wt.% and 45 wt.%, respectively, and traces of Fe and Cr were registered in some regions. The results from nanoindentation experiments showed that the indentation hardness in the bicuspid part of archwires used for six weeks decreases by about 154%, and the indentation modulus decreases by about 44% compared to as received archwires, probably due to the changes in the morphology. Statistically significant differences in the chemical content are found for the anterior and bicuspid regions, while in the mechanical properties, for the bicuspid and posterior regions of the investigated archwires. The obtained results give orthodontists important information about the physicochemical and mechanical properties of the Bio-active™ multi-force archwires during their clinical use.

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

“…The timeframe includes the average amount of time that the patient's orthodontic wires are in their mouth. Our investigations of the Bio-active™ archwire's chemical composition show similar results-the Ni and Ti wt% remain unchanged even after prolonged use, and trace amounts of Fe and Cr were registered in all regions of the archwire [38]. The deactivation force, also known as the unloading force, of the appliance is what acts to level and align the teeth, not the activation force.…”

“…The archwire’s biomechanical properties (shape memory, force, and superelasticity) can also be attributed to heat-activated archwires. Its shape memory applies progressive forces from the midline to the posterior sections [ 37 , 38 , 39 , 40 ].…”

“…Changes in the ratio of nickel to titanium or the addition of minor amounts of additional elements [ 31 ] can reduce this range. Therefore, the characteristics of the orthodontic archwires are influenced by their elemental composition [ 38 ]. Because DSC enables the determination of the phase transition temperature and the amount of energy emitted or absorbed during the heating or cooling processes, it is one of the most helpful techniques for assessing the TTR of orthodontic archwires [ 42 , 43 ].…”

“…The nanoindentation test has the advantage of providing both elastic modulus and hardness data from a single test; however, it requires that the surface of the studied sample be completely flat [ 55 ]. In one of our previous studies [ 38 ], we used dynamic nanoindentation to test the indentation hardness and modulus of the Bio-active archwire. The test had to be modified, as the sample had a high surface roughness, causing problems for the indenter to detect the surface.…”

Effects of Clinical Use on the Mechanical Properties of Bio-Active® (BA) and TriTanium® (TR) Multiforce Nickel-Titanium Orthodontic Archwires

“…When choosing an appropriate archwire for a certain stage of orthodontic treatment with a fixed technique, information about the mechanical properties is of the utmost importance for the practitioners. In our previous scientific research, we choose to use Nanoindentation as a testing method for mechanical properties [ 16 , 17 ]. This technique allows simultaneous quantitative measurements of hardness.…”