Distraction device for palatal expansion

A distraction device for palatal expansion with a central expanding element having an adjustable length, characterised in that it comprises:

• a nut with opposite sides, comprising a first side with an opening with a first inner thread and a second side, opposite the first side, with an opening with a second inner thread having a smaller diameter than the first inner thread,
• a first threaded rod with a thread with a first diameter and a cavity having a smaller diameter than said first diameter, and an external end on one of the sides, with the thread being screwed onto the first inner thread of the nut, and
• a second threaded rod with a thread with a second diameter, and an external end, with the thread being screwed onto the second inner thread of the nut, and the diameter of the thread (8.1) being smaller than the diameter of the cavity of the first rod for insertion into said cavity,
• determining at least two positions, a non-expanded initial position, wherein the external end of the second threaded rod is in contact with the nut and inserted into the cavity of the first threaded rod, determining a minimum length between the two external ends of the device, and an expanded final position, wherein the external end of the second threaded rod is separated from the nut and outside the cavity of the first threaded rod, determining a maximum length between said two external ends.