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Updated: Apr 16, 2026

Force System with Vertical V-Bends: A 3D In Vitro Assessment of Elastic and Rigid Rectangular Archwires
Published on: July 24, 2018
Photoelastic analysis of stress generated by wires when conventional and self-ligating brackets are used: a pilot
Guilherme Caiado Sobral1, Mário Vedovello Filho2, Viviane Veroni Degan2
1School of Dentistry, University of Araras.
Objective:
By means of a photoelastic model, this study analyzed the stress caused on conventional and self-ligating brackets with expanded arch wires.
Method:
Standard brackets were adhered to artificial teeth and a photoelastic model was prepared using the Interlandi 19/12 diagram as base. Successive activations were made with 0.014-in and 0.018-in rounded cross section Nickel-Titanium wires (NiTi) and 0.019 x 0.025-in rectangular stainless steel wires all of which made on 22/14 Interlandi diagram. The model was observed on a plane polariscope--in a dark field microscope configuration--and photographed at each exchange of wire. Then, they were replaced by self-ligating brackets and the process was repeated. Analysis was qualitative and observed stress location and pattern on both models analyzed.
Conclusions:
Results identified greater stress on the region of the apex of premolars in both analyzed models. Upon comparing the stress between models, a greater amount of stress was found in the model with conventional brackets in all of its wires. Therefore, the present pilot study revealed that alignment of wires in self-ligating brackets produced lower stress in periodontal tissues in expansive mechanics.
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