Micrographic evaluation of different widia compositions of orthodontic pliers submitted to peracetic acid and intensive use

• Published in: Revista de Odontologia da UNESP 2020, Vol.49
• Main Authors: MARCIAL, Érika Zoli, NEVES, José Guilherme, CORRER-SOBRINHO, Lourenço, MENEZES, Carolina Carmo de, GODOI, Ana Paula Terossi de, VEDOVELLO FILHO, Mário, COSTA, Ana Rosa
• Format: Article
• Language: English
• Subjects: orthodontics; peracetic acid; Sterilization
• ISSN: 0101-1774; 1807-2577
• DOI: 10.1590/1807-2577.02120

Abstract Introduction The sterilization and disinfection procedures should be adapted to the chemical profile of the metal alloys present in the instruments. Objective This study aimed to perform a micrographic assessment on the surface characteristics of the widia of orthodontic pliers with two alloy compositions subjected to the action of 0.2% peracetic acid and intensive use. Material and method Twenty distal cutting pliers were divided into two groups (n=10) according to widia composition (%wt): W1- 85% to 87% of tungsten carbide (TC) and other components in the proportion of 13% to 15% and W2 – 87.5% to 88.5% of tungsten carbide and 11.5% to 12.5% for other components. All the pliers were assessed in a stereoscopic magnifying glass (32x) after three treatments: before use (T0); after cutting 100 segments of rectangular stainless-steel wires – intensive use (T1); and after 100 sterilization cycles in 0.2% peracetic acid and intensive use (T2). The cutting sites of all pliers were standardized. Widia regions were defined by line “A” representing T1 and line “B” representing T2. A frequency distribution table and Fisher’s exact test (α=0.05) was performed. We assessed two widia from each composition and treatment in SEM and energy-dispersive X-ray spectroscopy (EDS/SEM). Result The results showed that W1 pliers presented significantly fewer defects after the sterilization cycles with peracetic acid and intensive use than W2 pliers (p=0.0198). There were no differences between both pliers after intensive use (p=1.000). Conclusion The SEM images and EDS analyses showed changes in widia surfaces after the different treatments. Widia composition affected the resistance of the orthodontic pliers after sterilization cycles with 0.2% peracetic acid and intensive use. Resumo Introdução Os procedimentos de esterilização e desinfecção devem ser adaptados ao perfil químico das ligas metálicas presentes nos instrumentos. Objetivo O objetivo do estudo foi realizar uma avaliação micrográfica das características da superfície da widia de alicates ortodônticos com duas composições de ligas submetidas à ação de ácido peracético a 0,2% e uso intensivo. Material e método Vinte alicates de corte distal foram divididos em dois grupos (n=10), de acordo com a composição widia (% em peso): W1- 85% a 87% de carboneto de tungstênio e outros componentes na proporção de 13% a 15% e W2 - 87,5% a 88,5% de carboneto de tungstênio e 11,5% a 12,5% para outros componentes. Os alicates fo