Method of manufacturing superelastic endodontic files and files made therefrom
AssigneeOrmco Corporation
InventorsFarrokh Farzin-Nia, William Otsen
Life of this patent
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Abstract
A method of forming a superelastic endodontic file by grinding a superelastic wire to form a file blank, and rotating a first end of the blank while preventing rotation of a second end of the blank is disclosed. The file blank is maintained in the austenite phase until twisted to form a stress induced martensite which is plastically deformed by the twisting. A heat treatment step may be performed prior to twisting, during twisting or after twisting of the preform. The method disclosed allows for increased flexibility in the design of files including the production of a rhomboid superelastic file.
Claims30
A superelastic endodontic appliance formed by substantial plastic deformation of a preformed blank comprising the steps of:
- providing a preform having a predetermined cross section and formed of a superelastic material;
- twisting the preform about the longitudinal axis to form an appliance having helically shaped edges;
- and
- maintaining the preform in the austenite phase until the twisting step.
A superelastic endodontic appliance formed by substantial plastic deformation of a preformed blank comprising the steps of:
- providing a preform having a predetermined cross section and formed of a superelastic material;
- twisting the preform about the longitudinal axis to form an appliance having helically shaped edges;
- and
- heating the preform to the austenite phase until twisting.
A superelastic endodontic file comprising a shaft having a working length;
- at least three cutting apices with adjacent cutting apices defining surfaces therebetween, said apices being permanently helically deformed about the working length of said shaft to form helically shaped cutting edges;
- and
- the surfaces of the shaft between adjacent longitudinal cutting edges defining elongated helical surfaces which are flat when viewed in transverse cross section.
A superelastic endodontic file comprising a shaft comprising:
- a handle section at its proximal end and a tip at its distal end a working length therebetween;
- four or more cutting apices helically arranged about said shaft;
- and
- wherein the working length of said shaft has a transverse cross-sectional area which is substantially rhomboidal along its length.
An endodontic file having cutting edges formed at the apices of a predetermined transverse cross-sectional shape, comprising:
- a working length portion, formed of a material exhibiting super-elasticity, having a predetermined transverse cross sectional area, and one or more apices defining cutting edges along the length thereof,
- said working length being permanently plastically deformed about its longitudinal axis to form said cutting edges at the apices thereof.
Dependencies are inferred from the claim text.