Bending characteristics of nitinol wire

Lopez, Isabelle; Goldberg, J.; Burstone, Charles J.

doi:10.1016/0002-9416(79)90075-7

Cited by 39 publications

(15 citation statements)

References 7 publications

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“…The selection of a wire is not only based on stiffness, but also information on springback, formability, joinability, and temperature-dependency variables. It is furthermore important to realize that wires may react differently in bending and torsion, and that the mode of loading may affect these properties (5).…”

Section: Introductionmentioning

confidence: 99%

Titanium‐niobium, a new finishing wire alloy

Dalstra

Denes

Melsen

2000

Clinical Orthodontics and Research

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The mechanical properties of the newly introduced titanium-niobium finishing wires were investigated. Both in bending and torsional loading mode, the stiffness, yield point, post-yield behavior, and springback of titanium-niobium wires were experimentally determined and compared to those of equally sized stainless steel wires. The experimentally obtained values were also validated with theoretical values from engineering formulas of cantilever deformations. The ratios for these parameters for the two materials proved to be different in bending and torsion. The stiffness of titanium-niobium in bending is roughly half of that of stainless steel, whereas in torsion it is roughly one-third. These characteristics enable the clinician to use titanium-niobium for creative bends without the excessive force levels of steel wires. The springback of titanium-niobium in bending is 14% lower than that of steel, whereas in torsion it is about the same or even slightly higher than that of steel, thus making it possible to utilize the wire for even major third-order corrections. Finally, the weldability of titanium-niobium wires was found to be good, so it is possible to weld wires of different dimensions together for the generation of differentiated force systems.

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Section: Introductionmentioning

confidence: 99%

Titanium‐niobium, a new finishing wire alloy

Dalstra

Denes

Melsen

2000

Clinical Orthodontics and Research

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“…An alloy submitted to constant strain within its elastic limit for a certain period of time can have its crystalline structure changed, which then tries to reorganize itself through stress relaxation by modifying its shape. 4 Such an effect had already been demonstrated in stainless steel, [6][7][8][9] Elgiloy, 9,10 nickeltitanium, 5,[7][8][9]12 and beta-titanium wires, 8,11 in clips of selfligating brackets, 13 and more recently in beta-titanium springs. 3,11 As is characteristic of this phenomenon, 9,10,12 the effect of stress relaxation was gradual, occurring majorly during the first 24 hours and gradually increasing during the 12 remaining weeks.…”

Section: Discussionmentioning

confidence: 98%

Effects of stress relaxation in beta-titanium orthodontic loops: Part II

Júnior

Caldas

Martins

2015

The Angle Orthodontist

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Objective: To determine which regions of beta-titanium T-loop springs (TLSs) are more affected by the stress relaxation over a 12-week period. Materials and Methods: Fifty TLS were previously activated by concentrated bends and divided into five groups of 10 each according to their evaluation periods: immediate assessment (G0), 24 hours (G1), 48 hours (G2), 1 week (G3), and 12 weeks (G4). Groups 1 to 4 were mounted into a structure simulating a clinical situation. After the experimental periods, the springs were scanned for measurement of their angles and numbered from 1 to 9. A two-way analysis of variance was used to detect differences among the angles measured and differences caused by time and also to detect interactions between those two factors. Tukey's test was used to find differences among the groups. Results: Time influenced the angulations of the TLSs (P , .001). Tukey post hoc test showed that G0 (84.1u) presented a different profile, whereas G1 (90.2u), G2 (90.7u), and G3 (91.1u) had similar profiles among each other, with G4 (92.6u) showing a mean value different from all other groups. A significant interaction was detected between activation time and angular deformation in the TLSs (P , .01). Conclusion: Stress relaxation was observed in the TLSs. It was greatest within 24 hours and gradually increased up to 12 weeks. Two regions were identified as responsible for the relaxation of the TLSs: one at the bend between the vertical extensions of the springs and the base arch and the other at the preactivation bends made in the base arch. (Angle Orthod. 2016;86:386-390.)

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“…To demonstrate the differences between the first nitinol wire and the superelastic NiTi wires in 1986, a three-point bending test was introduced by Miura. [ 12 ] However, many other authors have also advocated that the archwire should be tested under restraint so that the wire is not free at both ends to simulate the clinical situation. In addition, higher force values during loading and unloading are obtained, as compared with previous methods.…”

Section: Discussionmentioning

confidence: 99%

Impact of recycling on the mechanical properties of nickel-titanium alloy wires and the efficacy of their reuse after cold sterilization

et al. 2020

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OBJECTIVE: This study aimed to assess the feasibility of reusing nickel–titanium (NiTi) alloy wires after 6 weeks of intraoral use by evaluating the changes in the load-deflection properties and surface characterization of these alloy wires after cold sterilization by immersion in 2% of acidic glutaraldehyde for 10 h. MATERIAL AND METHODS: Twenty wires each in three groups of G1-as-received wires (ARW), G2-unsterilized used wires, and G3-sterilized used wires (SUW) were tested by the three-point bending test and scanning electron microscopy (SEM). The data were subjected to statistics, one-way analysis of variance, and Bonferroni posthoc test for comparison. RESULTS: Recycling of NiTi wires produced statistically insignificant changes in both the loading and unloading properties of the wires. The forces needed to twist the used wires, that is, G2-(UUW) and G3-(SUW) were lower than G1-(ARW), suggesting lowering of the stiffness of the wires. Superelasticity is well-maintained by G2-(UUW) and G3-(SUW) although there is an insignificant lowering of the forces exerted by them during loading and unloading. SEM demonstrated no increase in the pitting of surfaces in both G2-(UUW) and G3-(SUW); multiple areas were seen to be more smoothened over G2-(UUW) and G3-(SUW) NiTi wires surfaces. CONCLUSION: The findings of this study support the reuse of NiTi wires after 6 weeks of use in oral conditions followed by cold sterilization by immersion in 2% acidic glutaraldehyde for 10 h.

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Bending characteristics of nitinol wire

Cited by 39 publications

References 7 publications

Titanium‐niobium, a new finishing wire alloy

Titanium‐niobium, a new finishing wire alloy

Effects of stress relaxation in beta-titanium orthodontic loops: Part II

Impact of recycling on the mechanical properties of nickel-titanium alloy wires and the efficacy of their reuse after cold sterilization

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