Evaluation of Effects of Sterilization on Mechanical Properties of Orthodontic Wires

Abstract

The frequency of exposure of dental personnel to infection and of patients to cross infection from contaminated instruments have prompted concern about adequate sterilization of dental instruments. Guidelines have been published by various professional bodies recommending methods of sterilization of dental instruments. Aims and objectives: The purpose of this study was to evaluate the effects of sterilization on the mechanical properties of wires. Materials and methods: Forty samples each of stainless steel, elgiloy, nitinol and -titanium wires of 5 length of 0.016 (round) dimension were subjected to dry heat sterilization, steam autoclave and 2% glutaraldehyde sterilization. Following sterilization, these wires were tested on Lloyds Universal Testing Machine. Graphs from each sample were analyzed to determine the ultimate tensile strength, 0.1% yield strength, modulus of elasticity and percentage elongation at break. Results: Dry heat sterilization, autoclave, 2% glutaraldehyde solution had no effect on ultimate tensile strength, 0.1% yield strength, modulus of elasticity and percentage elongation of stainless steel and elgiloy wires. Tensile strength and yield strength of Nitinol and -titanium wires together with percentage elongation of -titanium wires significantly increased following dry heat sterilization and autoclave. No detrimental effects on properties of wires were observed. These sterilization procedures could be safely recommended for sterilization of orthodontic wires.