Shape memory orthodontic archwire having variable recovery stresses
AssigneeOrmco Corporation
InventorsRohit Chaman Lal Sachdeva, Farrokh Farzin-Nia
Life of this patent
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Abstract
Orthodontic archwires and methods of making such archwires. The archwire includes a shape memory alloy having a preset shape for exerting forces on teeth during orthodontic treatment. The alloy, which preferably is comprised of at least three elements (e.g., Ni, Ti and Cu), has a transformation temperature (A.sub.f) greater than about 25.degree. C., whereby the orthodontic archwire produces forces at normal mouth temperature which are greater than the forces produced at normal room temperature. The orthodontic archwire also preferably has a variable modulus of elasticity.
Claims39
An orthodontic archwire, comprising:
- a shape memory alloy having a preset shape for exerting forces on teeth during orthodontic treatment, said alloy having a transformation temperature (A.sub.f) greater than about 25.degree. C., whereby said orthodontic archwire produces forces at normal mouth temperature which are greater than the forces produced at normal room temperature,
- said shape memory alloy comprised of at least three elements, each of which is present in an amount equal to or greater than about 2% by weight;
- said present shape including at least one curve outside of the plane of the archwire;
- and
- said archwire having a variable modulus of elasticity.
A method of making an improved orthodontic archwire of a shape memory alloy, comprising the steps of:
- forming a shape memory alloy archwire comprised of at least three elements each of which is present in an amount equal to or greater than about 2% by weight into a preselected arch shape for exerting forces on teeth during orthodontic treatment;
- heat treating said archwire to provide it with a transformation temperature (A.sub.f) greater than about 25.degree. C., whereby said orthodontic archwire produces corrective forces at normal mouth temperature that are greater than the forces produced at normal room temperature;
- and
- selectively thermally treating sections of said archwire to provide it with a variable modulus of elasticity.
A method of orthodontic treatment, comprising the steps of:
- adhering a plurality of orthodontic brackets to a plurality of teeth on a maxillary or mandibular jaw;
- and
- attaching an orthodontic archwire to said brackets, said archwire comprising a shape memory alloy comprised of at least three elements, each of which is present in an amount equal to or greater than about 2% by weight, said archwire having a present shape for exerting forces on teeth during orthodontic treatment, said alloy having a transformation temperature (A.sub.f) in the range of from about 25.degree. C. to about 45.degree. C., whereby said orthodontic archwire produces forces at normal mouth temperature that are greater than the forces produced at normal room temperature, said archwire further having a variable modulus of elasticity and at least one curve outside the plane of the archwire.
Dependencies are inferred from the claim text.