FORCE DELIVERY OF NI-TI COIL SPRINGS

Sentalloy springs (GAG, Central Islip, N.Y.) of the open and closed ty pe were investigated with a special designed device. The closed coil s prings were subjected to a tensile and the open coil springs to a comp ression test. After a first measurement, the springs were activated fo r a period of 4 weeks and then reinvestigated with the same procedure. It could be shown distinctly that, with the different coil springs, t he force delivery given by the producer could be achieved only within certain limits. To remain in the martensitic plateau, changed activati on ranges, and for the Sentalloy coil springs white and red of the ope n and dosed type, also changed force deliveries had to be taken into a ccount. There was a distinct decrease in force delivery between the fi rst and second measurement. After considering the loading curves of al l the Sentalloy coil springs and choosing the right activation range r espective to the force delivery, it was found that the coil springs de liver a superior clinical behavior and open new treatment possibilitie s.