Endodontic instrument for drilling the root canals of a tooth

Abstract

An endodontic instrument for drilling the root canals of a tooth. The instrument comprises a working area for forming and/or shaping and/or cutting the wall of the root canal of the tooth. The working area is provided with a supporting endpiece that can be attached to a manual or mechanically driven mounting. The working area is arranged so as to assume a stowed configuration when the instrument is in an inoperative position to the working position, and vice versa, being cause by a predetermined variation in the temperature of the instrument. To this end, the working area is made from a wire of a metal alloy having shape-memory properties or particular elasticity properties.

1 - 14 . (canceled) 
     
     
         15 . An endodontic instrument, particularly an instrument for drilling a root canal in a patient's tooth, the instrument ( 10 ) defining a longitudinal axis and comprising:
 a working area ( 11 ) for at least one of forming, shaping, and cutting a wall of a root canal ( 21 ) of a tooth ( 20 ), and the working area ( 11 ) being equipped with a supporting end piece ( 13 ) that is attachable to a mounting ( 14 ),   at least the working area ( 11 ) having a retracted configuration that is at least partially rectilinear in shape,   when the instrument ( 10 ) is in an inoperative position, the instrument being in a martensitic phase,   when the instrument is in a working position, an expanded structured configuration of the working area ( 11 ) adapting to a shape of the root canal with the instrument then being in an austenitic phase, and   passage from the martensitic phase to the austenitic phase being triggered by a first predetermined variation in a temperature of the instrument, and a return of the instrument, from the austenitic phase to the martensitic phase, being triggered by a second predetermined variation in the temperature of the instrument.   
     
     
         16 . The endodontic instrument according to  claim 15 , wherein at least the first predetermined variation in the temperature of the instrument is triggered during use of the instrument after introduction into the root canal. 
     
     
         17 . The endodontic instrument according to  claim 16 , wherein the first predetermined variation in the temperature of the instrument is a temperature elevation. 
     
     
         18 . The endodontic instrument according to  claim 17 , wherein the temperature elevation that triggers passage from the martensitic phase to the austenitic phase occurs in a temperature ranging from 0° to 60° C. 
     
     
         19 . The endodontic instrument according to  claim 17 , wherein the temperature elevation that triggers passage from the martensitic phase to the austenitic phase occurs in a temperature ranging from 25° to 40° C. 
     
     
         20 . The endodontic instrument according to  claim 15 , wherein the second predetermined variation in the temperature of the instrument is a temperature decrease of the instrument. 
     
     
         21 . The endodontic instrument according to  claim 19 , wherein the temperature decrease to a transformation temperature, which triggers passage from the austenitic phase to the martensitic phase, occurs in a temperature ranging from 60° to 0° C. 
     
     
         22 . The endodontic instrument according to  claim 19 , wherein the temperature decrease to a transformation temperature, which triggers passage from the austenitic phase to the martensitic phase, occurs in a temperature ranging from 40° to 25° C. 
     
     
         23 . The endodontic instrument according to  claim 15 , wherein at least the working area ( 11 ) is made of a metal alloy having shape memory properties allowing the working area ( 11 ) to assume a retracted configuration, at ambient temperature, and an expanded structured configuration, at a higher temperature, either at the time of or after its introduction into the root canal ( 21 ). 
     
     
         24 . The endodontic instrument according to  claim 23 , wherein the metal alloy with shape memory properties is an alloy selected from a group of alloys consisting of: nickel-titanium, copper-zinc-aluminum-nickel, copper-aluminum-nickel, or zinc-cooper-gold-iron or a combination of two or more of these alloys. 
     
     
         25 . The endodontic instrument according to  claim 15 , wherein the working area ( 11 ) on the instrument ( 10 ), in the expanded structured configuration, has a twisted shape. 
     
     
         26 . The endodontic instrument according to  claim 15 , wherein the working area ( 11 ) on the instrument ( 10 ), in the expanded structured configuration, has a generally flat auger shape. 
     
     
         27 . The endodontic instrument according to  claim 15 , wherein the working area ( 11 ) on the instrument ( 10 ), in the expanded structured configuration, has a generally circular corkscrew shape. 
     
     
         28 . The endodontic instrument according to  claim 15 , wherein in the expanded structured configuration, the working area ( 11 ) on the instrument ( 10 ) comprises portions with one of at least one cutting edge, at least one smoothing edge, at least one abrasive surface, and at least one end section forming an angle with the longitudinal axis of the instrument. 
     
     
         29 . The endodontic instrument according to  claim 15 , wherein the working area ( 11 ) on the instrument ( 10 ), in the expanded structured configuration, is tubular and comprises two end sections ( 12   a,    12   b ) forming an angle relative to the longitudinal axis of the instrument, and the two end sections are designed to from a cone during axial rotation by the instrument ( 10 ). 
     
     
         30 . The endodontic instrument according to  claim 15 , wherein the working area ( 11 ), after the working area ( 11 ) is used in the expanded structured configuration, resumes the retracted configuration through a mechanical action. 
     
     
         31 . An endodontic instrument for drilling a root canal in a tooth of a patient, the instrument ( 10 ) defining a longitudinal axis and comprising:
 a working area ( 11 ) for at least one forming, shaping, and cutting a wall of the root canal ( 21 ) of the tooth ( 20 ), and the working area ( 11 ) being connected to a supporting end piece ( 13 );   a mounting couples the supporting end piece which supports the working area;   the working area ( 11 ) having both a martensitic phase and an austenitic phase depending on a temperature of the instrument;   the instrument, in the martensitic phase, being in an inoperative position in which the working area assumes a retracted configuration and is at least partially rectilinear in shape;   the instrument, in the austenitic phase, being in a working position in which the working area assumes an expanded structured configuration and being shaped in a shape of the root canal; and   once the temperature of the instrument experiences a first predetermined variation, the working area transitions from the martensitic phase to the austenitic phase, and once the temperature of the instrument experiences a second predetermined variation the working area transitions from the austenitic phase to the martensitic phase.