Self adjusting instrument

Abstract

The invention is an instrument for cleaning and/or shaping and/or widening a channel that exists in or through a solid object. The design of the instrument the superelastic and shape memory properties of the material from which it is made, allow the inner volume enclosed by the instrument, its outer contour, or both to change as a result of the forces exerted upon it while working, thereby shaping the instrument to the three-dimensional contour of the channel. A preferred embodiment of the instrument is an endodontic file for use in the cleaning, shaping, and widening stages of a root canal procedure.

1 . A method for widening a root canal, the method comprising:
 (a) providing an endodontic instrument comprising an elongated narrow balloon;   (b) inserting the endodontic instrument into the root canal;   (c) inflating the balloon with fluid so as to bias the endodontic instrument into contact with the sides of the root canal; and   (d) moving the endodontic instrument in a motion including at least one of rotation and longitudinal reciprocation within the root canal while the balloon maintains contact between the endodontic instrument and the sides of the root canal.   
     
     
         2 . The method of  claim 1 , wherein the endodontic instrument further comprises an abrasive material on an outer surface of the balloon. 
     
     
         3 . The method of  claim 1 , wherein the endodontic instrument further comprises an elongated support element deployed within the balloon. 
     
     
         4 . The method of  claim 3 , wherein said elongated support element is attached to the balloon at a distal end of the balloon. 
     
     
         5 . The method of  claim 1 , wherein the endodontic instrument further comprises a plurality of abrasive elements deployed around the balloon so as to be pressed by the balloon against the wall of the root canal when the balloon is inflated. 
     
     
         6 . The method of  claim 1 , wherein the endodontic instrument further comprises a plurality of cutting elements deployed around the balloon so as to be pressed by the balloon against the wall of the root canal when the balloon is inflated. 
     
     
         7 . The method of  claim 1 , wherein the endodontic instrument further comprises a plurality of flexible elongated elements deployed around the balloon so as to be pressed by the balloon against the wall of the root canal when the balloon is inflated. 
     
     
         8 . The method of  claim 7 , wherein the flexible elongated elements are deployed extending along a longitudinal direction of the balloon. 
     
     
         9 . The method of  claim 1 , further comprising disposing an abrasive slurry between the sides of the root canal and the endodontic instrument. 
     
     
         10 . The method of  claim 1 , wherein said motion is primarily longitudinal oscillation. 
     
     
         11 . The method of  claim 1 , wherein the root canal is non-circular in cross-section, and wherein the fluid pressure in the balloon maintains contact of the endodontic instrument with the wall of the root canal around the non-circular cross-section of the root canal. 
     
     
         12 . The method of  claim 1 , wherein the root canal has a distal portion which is wider than a proximal portion, and wherein the fluid pressure in the balloon maintains contact of the endodontic instrument with the wall of the root canal in both the proximal portion and the distal portion. 
     
     
         13 . The method of  claim 1 , wherein the fluid pressure in the balloon increases a transverse dimension of the endodontic instrument during said moving as material is removed from the wall of the root canal. 
     
     
         14 . The method of  claim 1 , further comprising deflating the balloon prior to removal of the endodontic tool from the root canal. 
     
     
         15 . An endodontic system for widening a root canal, the system comprising:
 (a) an endodontic instrument comprising:
 (i) an elongated narrow balloon, and 
 (ii) at least one material remover selected from the group consisting of an abrasive material on an outer surface of the balloon; a plurality of abrasive elements deployed around the balloon; and a plurality of cutting elements deployed around the balloon; and 
   (b) a dental handpiece to which said endodontic instrument is selectively attachable, said handpiece comprising:
 (i) a fluid connection configured for supplying fluid pressure to said balloon so as to bias said endodontic instrument into contact with the sides of a root canal, and 
 (ii) a drive generating motion of the endodontic instrument including at least one of rotation and longitudinal reciprocation. 
   
     
     
         16 . The endodontic system of  claim 15 , wherein said endodontic instrument further comprises an elongated support element deployed within said balloon. 
     
     
         17 . The endodontic system of  claim 16 , wherein said elongated support element is attached to said balloon at a distal end of said balloon. 
     
     
         18 . The endodontic system of  claim 15 , wherein said at least one material remover comprises an abrasive material on an outer surface of the balloon. 
     
     
         19 . The endodontic system of  claim 15 , wherein said at least one material remover comprises a plurality of abrasive elements deployed around the balloon. 
     
     
         20 . The endodontic system of  claim 15 , wherein said at least one material remover comprises a plurality of cutting elements deployed around the balloon.