Endodontic Instrument

Abstract

A method of manufacturing endodontic instruments is disclosed. Each of the instruments includes a substantially non-cutting pilot portion, a relatively short working portion, and a flexible shank portion which is of a substantially smaller average circumferential span than the working portion. The working portion of one instrument may have a maximum circumferential span as that of the blank from which it is made. The instrument may be treated with either a surface treatment and/or a bulk treatment. The instrument may have a handle at its distal end for manual manipulation, or may be adapted for attachment to a mechanical handpiece. The non-cutting pilot, the short length of the working portion, and the flexibility of the shank combine to allow the instrument to be used in curved root canals without causing undue change in the natural root canal contours.

1 . A method for manufacturing an endodontic instrument comprising: 
 providing a blank for making an instrument, said blank having a circumferential span;    grinding said blank to form a non-working shank portion having a proximal end and a distal end, at least a portion of the shank having a substantially smaller circumferential span than that of the blank;    forming a working portion extending not more than the length of the non-working shank on said blank adjacent the distal end of the non-working shank, and having a maximum circumferential span substantially corresponding to the circumferential span of the blank;    forming a pilot portion near one end of the blank close to the working portion;    treating at least a portion of the instrument comprising at least a portion of the shank portion, the working portion, the pilot portion or combinations thereof; and    attaching at least a portion of the treated shank portion to a handle portion.    
   
   
       2 . The method of  claim 1  wherein said pilot portion comprises a non-cutting portion, abrasive surfaces, or a continuous extension of the working portion.  
   
   
       3 . The method of  claim 1  further comprises flattening at least a part of the working portion.  
   
   
       4 . The method of  claim 1  wherein said treating the shank portion comprises roughening the surface.  
   
   
       5 . The method of  claim 1  wherein said treating comprises coating, sandblasting, anodizing, ion implantation, electro-polishing, etching, heat setting, cryogenic treatment or combinations thereof.  
   
   
       6 . The method of  claim 4  further comprises attaching said roughened portion to a handle.  
   
   
       7 . The method of  claim 1  wherein said treating is done prior to grinding or during the manufacturing of the blank.  
   
   
       8 . The method of  claim 1  wherein said working portion has a longitudinal axis and comprises at least one helical working surface; edges forming a continuous curve; edges twisting not more than 359° about the longitudinal axis; curved cutting edges about the longitudinal axis; straight cutting edges along the longitudinal axis; straight cutting edges at an oblique angle of the longitudinal axis; projections that are non-intersecting; or combinations thereof.  
   
   
       9 . The method of  claim 1  wherein said treating imparts a different color onto the treated surfaces.  
   
   
       10 . A method for manufacturing a set of an endodontic instruments comprising: 
 providing a set of blanks, said blanks having varying circumferential spans;    grinding each of said blank to form a non-working shank portion having a length, a proximal end, and a distal end, wherein at least a portion of said shank portion having a substantially smaller circumferential span than that of the blank;    forming a working portion on each blank adjacent to the distal end of said shank portion and extending not more than the length of the non-working shank, said working portion having a maximum circumferential span substantially corresponding to the circumferential span of the blank; and    forming a pilot portion near one end of the instrument close to the working portion.    
   
   
       11 . The method of  claim 10  wherein said pilot portion comprises a non-cutting portion, abrasive surfaces, or a continuous extension of the working portion.  
   
   
       12 . The method of  claim 10  further comprising treating at least a portion of each of the instruments comprising at least a portion of the shank, the working portion, the pilot portion or combinations thereof.  
   
   
       13 . The method of  claim 12  wherein said treating comprises coating, sandblasting, anodizing, ion implantation, electro-polishing, etching, heat setting, cryogenic treatment, or combinations thereof.  
   
   
       14 . The method of  claim 12  wherein said treating is performed prior to the grinding process, or during the manufacturing of the blank.  
   
   
       15 . The method of  claim 10  further comprises flattening at least a part of the working portion.  
   
   
       16 . A method for manufacturing a set of endodontic instruments comprising: 
 providing a set of groups of blanks, the set and groups each having a finite number of blanks, wherein each group having a different circumferential span from another group;    grinding each blank to generate a non-working shank portion having a length, a proximal end and a distal end, each instrument made from the same group of blanks has at least a portion towards the distal end having a substantially smaller circumferential span than that of the blank;    forming a working portion having cutting edges and a circumferential span adjacent said shank portion, said working portion extending not more than the length of the non-working shank portion;    forming a pilot portion adjacent the working portion;    wherein only one instrument in the set made from each group of blanks has a maximum circumferential span substantially corresponding to the circumferential span of each group of blanks.    
   
   
       17 . The method of  claim 16  wherein at least one of said instruments in the set made from the same group of blanks has at least a portion towards the proximal end having substantially the same circumferential span as that of the blank.  
   
   
       18 . The method of  claim 16  wherein the working portion has a longitudinal axis and comprises at least one helical working surface; edges forming a continuous curve; edges twisting not more than 359° about the longitudinal axis; curved cutting edges about the longitudinal axis; straight cutting edges along the longitudinal axis; straight cutting edges at an oblique angle from the longitudinal axis; projections that are non-intersecting; or combinations thereof.  
   
   
       19 . The method of  claim 16  further comprises treating at least a portion of each of the instruments including the shank, the working portion, the pilot portion or combinations thereof.  
   
   
       20 . The method of  claim 19  wherein said treating comprises coating, sandblasting, anodizing, ion implantation, electro-polishing, etching, heat setting, cryogenic treatment or combinations thereof.  
   
   
       21 . The method of  claim 19  wherein said treating comprises roughening the proximal end of the shank portion.  
   
   
       22 . The method of  claim 19  wherein said treating is performed during the manufacturing of the blank.  
   
   
       23 . The method of  claim 16  wherein the pilot portion comprises a non-cutting portion, abrasive surfaces or combinations thereof.  
   
   
       24 . The method of  claim 16  wherein each group has at least two blanks.  
   
   
       25 . The method of  claim 21  further comprises attaching said roughened portion to a handle.  
   
   
       26 . The instrument of  claim 19  wherein said treated portions have a different color from the untreated portions.