Force system evaluation of symmetrical beta-titanium T-loop springs preactivated by curvature and concentrated bends

Caldas, Sergei Godeiro Fernandes Rabelo; Martins, Renato Parsekian; Galvão, Marília Regalado; Vieira, Camilla Ivini Viana

doi:10.1016/j.ajodo.2010.11.022

Cited by 15 publications

(23 citation statements)

References 15 publications

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“…Analytical relations among spring characteristics, design, dimension, and activation distance in a given retraction loop must be considered to fully understand its biomechanical behavior (Setiawan et al). Several reports analyzed the effects of different wire crosssections, different pre-activation settings (symmetric arm activation vs. symmetric moments), and different IBD's on T-loops, either experimentally (Burstone;Manhartsberger et al, 1989;Kuhlberg & Burstone;Rose et al, 2009;Setiawan et al;Caldas et al, 2011aCaldas et al, , 2011b, or clinically (Martins et al;Keng et al, 2012;Xia et al, 2013;Li et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

M/F Changes after T-loop Upper Horizontal Bending in Segmented Arch Mechanics

Muñoz-Rendón

Montoya-Góez

Gómez-Gil

2016

Int. J. Odontostomat.

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βTi T-type loops are a frictionless, efficient alternative for extraction space closure. Changes in the upper horizontal portion of T-type loops to improve their mechanical behavior have been proposed, but differences in their biomechanical characteristics have not been well described. This stu dy analyzed the biomechanical differences among three T-type loops with differential bends in their upper horizontal portion. Ninety loops (0.017"x0.025" βTi) were bent and randomly divided in 3 groups according to the form of their upper horizontal portion (T [straight], M [convex], and C-loops [concave]), to evaluate force characteristics up to 6 mm of activation. Stiffness, maximum horizontal loads, total loop moments, and moment-to-force ratios were obtained. Nonparametric statistical analyses were used to test differences among groups. M-loops demonstrated lower force than T-and C-loops, and higher total loop moment than T-loops. A significant increase in M-loop moment-to-force ratio compared with T-or C-loops was obtained. C-and T-loops did not demonstrate significant differences in moment-to-force ratio between them. The convex upper bend in M-loops produced an increased total loop moment compared with T-loops. M-loops demonstrated moment-to-force values slightly higher than translation values, while the other loops reported only controlled inclination values at 6 mm of activation. M-loops are ideal when a higher control of root movement is indicated since the beginning of dental retraction in segmented arch mechanics.

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Section: Discussionmentioning

confidence: 99%

M/F Changes after T-loop Upper Horizontal Bending in Segmented Arch Mechanics

Muñoz-Rendón

Montoya-Góez

Gómez-Gil

2016

Int. J. Odontostomat.

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“…As it has already been suggested for NiTi close coil springs, 22 it may be a good idea to overactivate NiTi T-loops if a more constant force is desired. Compared with a beta-titanium T-loop, 5 where …”

Section: Discussionmentioning

confidence: 99%

“…[1][2][3][4] Despite those favorable characteristics, after 3-4 mm of deactivation 5,6 there is a significant decrease of force produced by the loop, which requires reactivation by the orthodontist or the addition of chain elastics over the loop 4 in order to generate more force. Nickel-titanium (NiTi) alloys are characterized by the presence of a pseudoelastic plateau in the loaddeflection graph during reverse transformation from stress-induced martensitic transformation, 7,8 a property that has been called "superelasticity."…”

Section: Introductionmentioning

confidence: 99%

Nickel titanium T-loop wire dimensions for en masse retraction

Almeida

Ribeiro²,

Martins

et al. 2016

The Angle Orthodontist

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Objective: To compare the force system produced by nickel-titanium T-loop springs made with wires of different dimensions. Material and Methods: Thirty compound T-loop springs were divided into three groups according to the dimensions of the nickel-titanium wire used for its design: 0.016" 3 0.022", 0.017" 3 0.025", and 0.018" 3 0.025". The loops were tested on the Orthodontic Force Tester machine at an interbracket distance of 23 mm and activated 9 mm. The force in the y-axis and the moment in the x-axis were registered while the calculated moment to force ratio was recorded at each .5 mm of deactivation. The data were analyzed by three analyses of variance of repeated measures to detect differences and interactions between deactivation and wire size on force, moment, and moment-force ratios (M/F). Results: All groups had significantly different forces (P , .001). The 0.016" 3 0.022" wire produced 1.78N of force while the 0.017" 3 0.025" and the 0.018" 3 0.025" produced 2.81 N and 3.25 N, respectively. The 0.016" 3 0.022" wire produced lower moments (11.6 Nmm) than the 0.017" 3 0.025" and 0.018" 3 0.025" wires, which produced similar moments (13.9 Nmm and 14.4Nmm, respectively). The M/F produced was different for all groups; 0.016" 3 0.022" T-loops produced 6.7 mm while the 0.017" 3 0.025" and 0.018" 3 0.025" T-loops produced 5.0 mm and 4.5 mm, respectively. An interaction was detected for all variables between deactivation and groups.Conclusion: The larger wires tested produced higher forces with slight increase on the moments, but the M/F produced by the 0.016" 3 0.022" wire was the highest found. (Angle Orthod. 2016;86:810-817.)

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“…In this issue, Blaya et al (2009) compared the mechanical behavior of different orthodontic retraction loops and concluded that the alloy of the wire and the height of the loop would be more important than the loop design (21). In addition to loop height and designs several factors have been shown to affect the force exerted by a loop spring including the alloy of the wire, the cross-section of a wire, the mode of loop preactivation and the temperature (19,22,23). Not to be lost in this discussion, it is worth mentioning that most of the studies on biomechanics of orthodontic loops, addressed closing loops which were activated in mesiodistal direction and the double vertical loop which is activated in buccolingual direction and was applied in this study has not receive much attention in the literature.…”

Section: Discussionmentioning

confidence: 99%

The Role of Loop Height and Design on its Force Characteristics in Alignment of Teeth: A Finite Element Analysis

Shahroudi

2016

Iran J Ortho

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Objectives: The aim of this study was to assess the effects of different orthodontic vertical loop height and design on its force characteristics at different amount of loop activation by means of finite element method (FEM) analysis. Results:The results of this study showed that the minimum amount of force was delivered by double vertical helical open loop with the height of 7 mm at the activation of 0.1 mm which was about 1.06E-01 N. The maximum amount of force was 2.2199 N which was delivered by double vertical open loop with height of 6mm at 1 mm activation. At each amount of activation the value of exerted force followed this order: DVOL 6 mm > DVOL 7 mm > DVHOL 6 mm > DVHOL 7 mm.Conclusions: According to this FEM study, considering its limitations, adding a helix in a double vertical open loop as well as increasing the height of loop can reduce the value of delivered force.

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Force system evaluation of symmetrical beta-titanium T-loop springs preactivated by curvature and concentrated bends

Cited by 15 publications

References 15 publications

M/F Changes after T-loop Upper Horizontal Bending in Segmented Arch Mechanics

M/F Changes after T-loop Upper Horizontal Bending in Segmented Arch Mechanics

Nickel titanium T-loop wire dimensions for en masse retraction

The Role of Loop Height and Design on its Force Characteristics in Alignment of Teeth: A Finite Element Analysis

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