The introduction of graded functionality in commercial superleastic orthodontic archwires (Morelli SE) was analyzed. There are few studies concerning the manufacturing of the functionally graded Ni-Ti orthodontic archwires reported in the literature. The load developed by these wires depends on the geometrical characteristics, the temperature and the strain. Normally, the conventional archwires generate constant forces in a wide range of displacement during the orthodontic treatment [I]. In order to have different forces of actuation in the incisive region (lower) and in the molar region (higher), different fabrication strategies have been proposed, such as (i) laser welding different wire segments [2], or (ii) separate heat treatment of different segments in a special furnace [3]. In the present study, a functional gradient was introduced in a superelastic Ni-Ti orthodontic archwire (Morelli - SE) by localized heat treatment using Joule heat effect. DSC measurements at different positions of the wire show that a microstructural gradient is present in such treated archwires (Fig. 1-a). A localized analysis along the heat-treated archwire, using synchrotron radiation based X-ray diffraction (SR-XRD) was used to identify the microstructure of the heat treated archwire with a finer spatial resolution (Fig. 1-b).
展开▼
