Application of superelastic NiTi wires for mandibular distraction

The aim of this work was to apply superelastic springs of NiTi wires into a new concept of a bone distractor based on the assumption of continuous and constant force acting during the process of mandible lengthening. For this purpose it was necessary to select the alloy and suitable thermomechanical treatment of the wires. The superelastic wires were tested by tension and bending and then the U- and Ω-shaped springs were characterised by stretching and unloading in order to determine the range of their deflection where the near constant force action is held. Tests carried out on 6-week-old pigs proved the possibility of 10 mm lengthening of the mandible after 3 weeks of continuous force acting only on decorticated (without osteotomy) bone.