Abstract The aim of this study was to evaluate the load-deflection characteristics of three types of nickel-titanium wires and investigate the effects of recycling on superelastic properties of them. MATERIALS AND METHODS: Thirty specimens for any of the single-strand Ni-Ti (Rematitan \"Lite\'), multi-strand Ni-Ti (SPEED Supercable) and Copper Ni-Ti (Damon Copper Ni-Ti) were tested. Ten specimens of each wire were subjected to three point bending test in the as-received condition (T0). The remaining wires were kept in a simulated oral environment for 2 months. Then, half of these specimens were tested for their load-deflection properties (T1), while the others were autoclave sterilized before testing (T2). Statistical analysis was performed by one-way ANOVA and Tukey test. RESULTS: Rematitan \"Lite\"showed significantly greater force than Damon Copper Ni- Ti and Damon Copper Ni-Ti, demonstrated significantly greater force than Supercable (p < 0.05). The effect of recycling on bending properties of nickel-titanium wires was significant (p < 0.05). T1 wires were generally associated with significantly lower forces than T0 specimens in deflections less than 2.0 mm, while load-deflection characteristics of T2 wires were not considerably different from those of T0 specimens. CONCLUSIONS: Supercable is useful when very light force is needed during orthodontic treatment, for example in severe crowding cases and traumatized teeth. Damon Copper Ni-Ti may be suitable for routine orthodontic treatment in adolescent and adult patients. It is suggested that clinicians who want to recycle nickel-titanium wires use autoclave sterilization.

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