Abstract
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.
Highlights
INTRODUCTIONThe orthodontic community, in recent years, has been concerned with the disinfection and sterilization of orthodontic instruments, being that the dental work environment represents a high risk of contamination[1,2]
The sterilization and disinfection procedures should be adapted to the chemical profile of the metal alloys present in the instruments
Exposure to the blood and saliva of patients during dental procedures leads to the possibility of acquiring diseases such as Hepatitis B and C, AIDS, among others, and being that the Hepatitis virus can survive for a week and that of AIDS for 72 hours in the environment in this context[4,5], appropriate infection control procedures and sterilization of dental instruments prevent cross-contamination between patients and prevent health problems between dental office staff and the dental surgeon[1,2,6]
Summary
The orthodontic community, in recent years, has been concerned with the disinfection and sterilization of orthodontic instruments, being that the dental work environment represents a high risk of contamination[1,2]. Peracetic acid is a chemical agent, which has shown some advantages over glutaraldehyde in the sterilization/disinfection processes This acid is a viable alternative since it is composed of acetic acid and hydrogen peroxide, its by-products being biocompatible substances[15]. Previous studies have shown that for high-level disinfection, the immersion time varies from 5 to 10 minutes and as a sterilant, they should remain between 15 to 30 minutes, varying according to the concentration and/or type of microorganisms and the presence or not of organic matter[6,17]. Until the present moment, no studies were found in literature that evaluated the action of peracetic acid 0.2% as a method of chemical sterilization in distal cutting pliers, as to the possible damages caused by this process on the active part of the pliers. The hypothesis of this study is that both W1 and W2 exhibit the same behavior (1) against intense use (after 100 cuts of 0.019 “x 0.025” steel rectangular wires) and (2) after 100 cycles of sterilization with peracetic acid 0.2% followed by heavy use
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