Photoelastic analysis of stress generated by wires when conventional and self-ligating brackets are used: A pilot study

Guilherme Caiado SOBRAL, Mário VEDOVELLO FILHO, Viviane Veroni DEGAN, Milton SANTAMARIA JR

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.

Keywords: Orthodontic brackets. Dental arch. Corrective orthodontics.

How to cite: Sobral GC, Vedovello Filho M, Degan VV, Santamaria Jr M. Photoelastic analysis of stress generated by wires when conventional and self-ligating brackets are used: A pilot study. Dental Press J Orthod. 2014 Sept-Oct;19(5):74-8. DOI: http://dx.doi.org/10.1590/2176-9451.19.5.074-078.oar

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