[The clinical use of the new NiTi-SE-steel uprighting spring].

Abstract

In clinical practice the NiTi steel uprighting spring presented in this study has been employed up until now to upright 30 molars. The advantage of this spring is that in large areas the pseudoelastic part of the spring transfers constant moments and forces to the molars. In addition, the steel part makes it possible to simply and easily adjust and fasten alpha-bends. Because of the relatively small uprighting moments of 10 up a maximum of 25 Nmm such an uptighting spring can also be applied without any modifications in cases in which the molars are tipped up to 50 degrees. Going beyond this our study determined that it is possible to exert intrusive forces of 0.4 N over the entire uprighting area by bending-in an 45 degrees alpha-bend. From a 15 degrees tipping on up the uprighting moments applied to molars remain relatively constant and they are only dependent on the bent alpha-activation. An uprighting by intrusive force on the molars can also be achieved through an alpha-activation of 0 degree (90 degrees + 40 degrees), when the vertical length of the pegs is enlarged. An on average 1.43 mm per month root mesialization of the uprighting spring with the Memory Maker, should such for whatever reason be considered desirable, take place only in the final stage. In almost every case of molar uprighting it is possible to fasten a figure eight ligature from the molar to the cross tube. The uprighting spring presented here combined with a cross tube proves to be an effective method for achieving a fast and trouble free uprighting of molars.