Evaluation of the Biomechanical Properties of Austenitic Stainless Steel Fixed Retainers

Abstract

The insertion of the fixed retention is an important stage of the orthodontic treatment after fixed appliances. The fixed retainers used in orthodontic treatments must be passive towards teeth, without developing any stress. This characteristic is challenging to achieve due to the mechanical properties (bending properties, stiffness) of the materials the retainers are manufactured from. Residual stress might be generated because of their flexibility and because the chemical composition of the stainless steel wires.This study aims to determine the mechanical properties of different austenitic stainlees steel wires used in retention. Also, we have compared the mechanical properties of wires with different sizes, as well as wires with the same size, new and intra-orally used. The results confirm that the mechanical parameters of the two types of wires used in fixed retention (3 braided round wires and 6 braided Flat wires) present statistically insignificant differences. The study also reflects that the mechanical properties of the intra-orally used wires showed decreased values of the parameters.