Deflection and Flexural Strength Effects on the Roughness of Aesthetic-Coated Orthodontic Wires.

Cibele Gonçalves De Albuquerque,Américo Bortolazzo Correr,Carlos Alberto Tubel,Giovana Cherubini Venezian,Silvia Amélia Scudeler Vedovello,Milton Santamaria Jr

doi:10.1590/0103-6440201700630

Cibele Gonçalves De Albuquerque, Américo Bortolazzo Correr + Show 4 more

Open Access

https://doi.org/10.1590/0103-6440201700630

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Abstract

The aim was to evaluate the flexural strength and the effects of deflection on the surface roughness of esthetic orthodontic wires. The sample consisted of 70 archwire 0.014-inch: polytetrafluorethylene (PTFE)-coated Nickel-Titanium (Niti) archwires (Titanol Cosmetic-TC, Flexy Super Elastic Esthetic-FSE, esthetic Nickel Titanium Wire-ANT); epoxy resin-coated Niti archwires (Spectra-S, Niticosmetic-TEC); gold and rhodium coated Niti (Sentalloy-STC) and a control group (superelastic Niti (Nitinol-NS). The initial roughness was evaluated with a rugosimeter. After that, the wires were submitted to flexural test in an universal testing machine. Each wire was deflected up to 2 mm at a speed of 1 mm/min. After flexural test, the roughness of the wires was evaluted on the same surface as that used for the initial evaluation. The data of roughness and flexural strength were analyzed by one-way ANOVA and Tukey's test (a=0.05). Student t-test compared roughness before and after deflection (a =0.05). The roughness of S and ANT (epoxy resin and PTFE-coated wires, respectively), before and after deflection, was significantly higher than the other groups (p<0.05). Wire deflection significantly increased the roughness of the wires S and STC (p<0.05). The flexural strength of groups FSE and NS (PTFE and uncoated) was higher compared with that of the other groups (p<0.05). We concluded that the roughness and flexural strength of the orthodontic wires does not depend on the type of the esthetic coating, but it is influenced by the method of application of this coating. The deflection can increase the roughness of the esthetic orthodontic wires.

Highlights

The concern of the patients about esthetics is not restricted to correction of the malocclusion, and with the appearance of the orthodontic appliance
One of the methods is to cover the surface of the metal arch wire with polytetrafluoroethylene (PTFE) or with epoxy resin with a color similar to that of teeth
Surface roughness is an important property of the orthodontic arch wire [2], since they determine the contact area of the wires with the tissues and other orthodontic appliance accessories

Summary

Introduction

The concern of the patients about esthetics is not restricted to correction of the malocclusion, and with the appearance of the orthodontic appliance. One of the methods is to cover the surface of the metal arch wire with polytetrafluoroethylene (PTFE) or with epoxy resin with a color similar to that of teeth. Another method is to cover the orthodontic wires with gold and rhodium, denominated white metals [1]. In addition to esthetic appearance, the development of esthetic orthodontic archwires aim to attain mechanical properties similar to the metallic wires [1]. Problems have been related to esthetic archwires during clinical use such as color change, cracks in the esthetic coating leading exposition of the subjacent metal, causing a negative visual impact and jeopardizing the sliding mechanics [3], since archwires with rougher surfaces generate more friction [4]

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