Patent ID: 6499996
Filing Date: 2002-12-31
Classification: A61C

Abstract:
Jackscrew for use in correcting misalignments of teeth, comprising two main bodies (1,2), whose mutual separation is adjustable by means of a spindle (3) provided with an operating part (5) and, continuous with that part, one or two screw-thread sections (7,11) the operating part (5) being rotatably mounted in one body (1) and one screw-thread section (11) being rotatably mounted in the other body (2), further comprising straight-line guide elements (22,23) which engage with both bodies (1,2) and guide them in a straight line while also preventing any relative rotation when the separation between the bodies is altered, and a threaded sleeve (13,14) on each of the screw-thread sections (7,11) of the spindle (3) the threaded sleeve (13,14) being guided inside a recess (6,10) in the respective body (1,2) and along the spindle (3) so as not to rotate relative to the body and transmitting its sliding motion to the bodies (1,2) via a spring (18,19) which determines the expansion force, characterized in that the spring (18,19) is made from a shape-memory alloy which is pseudo-elastic at temperatures prevailing inside the mouth.