[Fundamental studies on superelastic Ni-Ti alloy for wire clasp].

In order to apply Ni-Ti superelastic alloy to wire clasp in dentistry, the bending characteristics and the shape memory treatment of the wire were investigated. The wire cooled in iced water was more easily bent than that stored at room temperature . In both conditions, however, most of the wire specimens were broken by bending before the radius of curvature became less than three times the diameter of the wire . It was emphasized that a new design of the clasp should be developed for this wire. At the shape memory treatment, the gypsum-bonded casting investment material was suc cessfully used to maintain the prepared shape of the wire during the treatment . The optimum treating temperature was 450° C to give the wire superelasticity at the intraoral temperature .