Abstract: An orthodontic teeth alignment correction wire element made of an alloy represented by the chemical formula of Ti.sub.a Ni.sub.b-c C.sub.c, wherein a+b=100, b=50-52, c=0.25-5.0, or an alloy represented by the chemical formula of Ti.sub.a Ni.sub.b-c-d C.sub.c X.sub.d, wherein X is at least one element selected from V, Cr, Fe, Nb, Ta, W, and Al, wherein a+b=100, b=50-52, c=0.25-5.0, d=0.25-2.0, and exhibits pseudoelasticity at the natural human body temperature. The wire has different recovery forces at different sections therealong by heat treating those sections at controlled temperatures of 400.degree.-600.degree. C. and for controlled time periods of 10-150 minutes and thereafter reheat treating them. An orthodontic coil is made of each of the above-described alloy wires for correction of mismatch of the upper and the lower jaws.

Abstract: An orthodontic device comprises a bracket formed of a sintered polycrystal of alumina exhibiting light transmittance of 70 to 80% and an auxilliary bonding member formed of a soft, transparent or translucent, thin, synthetic resin plate having a mounting aperture formed therein for mounting the bracket therein and a plurality of graduations drawn thereon for indicating the depth from a reference point on the free end of a tooth being subjected to orthodontic treatment to the center of the bracket.

Abstract: An orthodontic coil spring is made of a shape-memory alloy wire which is wound into a coil and heat treated into a superelastic state. The coil spring imparts a predetermined spring force within a superelastic zone of deflection.