Patent ID: 7249414
Filing Date: 2007-07-31
Classification: A61C,Y10T

Abstract:
1. A method for manufacturing a canal instrument having a working cross-section comprising three flutes forming three cutting lips, wherein the three flutes have an “S” shape, and wherein the three cutting lips are located on the working cross-section at positions corresponding to vertices of an isosceles triangle, wherein the canal instrument has a working part with a substantially conical shape which tapers to a tip, wherein the flutes define a spiral having a pitch, and wherein the method comprises the steps of: grinding first and second flutes in a generally cylindrical blank during first and second machining operations, wherein the first and second machining operations are identical and successive machining operations performed at locations on the blank which are separated by an angle of 120°, and thereafter grinding a third flute in the cylindrical blank by performing a third machining operation, wherein the first and second machining operations are performed at a first depth, and wherein the third machining operation is performed at a second depth which is greater than the first depth; and varying the pitch of the spiral during the first, second and third machining operations so that the pitch increases with increased distance from the tip off the canal instrument.