Evaluation of super-elastic open spring coils (Ni-Ti) in orthodontic applications

The paper presents the main results of a measurement campaign to e valuate the mechanical characteristics of super-elastic open spring coils used in orthodontics. Several Ni-Ti open spring coils were tested in order to verify their mechanical response under planned deformations, by measuring the generated forces. A comparative anal ysis of force -displacement curves of different super elastics spring coil models was carried out in the temperature range 21.5°C to 49.0°C, to simulate their performances into the oral cavity. The results showed significant differences in comparison with manufacturer's indications.