Effect of different sterilization procedures on frictional properties of Nickel Titanium orthodontic wires

Abstract

The frequency of exposure of dental personnel to infection and of patient to cross contaminated instruments has prompted concern about adequate sterilization of dental instruments. Aim of the present study was to evaluate the changes in the frictional properties of Ni-Ti orthodontic wires after three sterilization methods with autoclave, oven and chemical agents. Materials and methods: In the present study the friction between Ni-Ti wires measuring 16 mm in diameter and 18-slot stainless steel brackets were measured and compared in four groups as follows: 1) without sterilization (as received); 2) after autoclave sterilization; 3) after sterilization in an oven; and 4) after chemical sterilization. Each group consisted of 30 specimens and friction was measured in a Universal testing machine. Kruskal-Wallis test was used to compare the shear stresses between the 4 study groups. Mann-Whitney test was used for the two-by-two comparison of the groups statistical significance was defined at P<0.05. Results: The maximum increase in friction due to sterilization was recorded in the oven group, followed by chemical agent and autoclave groups in descending order. Conclusion: Based on the results of the present study, all the three sterilization techniques increase the friction of Ni-Ti orthodontic wires