Patent ID: 7431588

Claim:
A sequence of instruments for preparing a root canal, particularly in an apical zone of the root canal, wherein the instruments include proximal portions for receiving a handle which allows the instruments to be used by hand or on a head of a contra-angle handpiece, and distal portions having a pointed tip, and wherein the sequence of instruments comprises at least one instrument having a blade with an active, cutting part having two conical sections which extend from the pointed tip and continuously along the blade, wherein, in combination with the pointed tip, each conical section of the instrument has a conicity which is greater than a conicity associated with a proximally oriented, immediately adjacent portion of the instrument, and wherein the sequence of instruments comprises seven instruments including: a first instrument having an apical diameter of 0.20 mm, wherein the first instrument includes a conical section having a conicity of 6%; a second instrument having an apical diameter of 0.20 mm, wherein the second instrument includes a conical section having a conicity of 4%; a third instrument having an apical diameter of 0.20 mm, wherein the third instrument includes a conical section having a conicity of 2%; a fourth instrument which is identical to the second instrument; a fifth instrument having an apical diameter of 0.20 mm, wherein the fifth instrument includes two conical sections having a first conicity of 6% for a distance of 4 mm along an active length of the fifth instrument, and a second conicity of 3% along remaining portions of the active length; a sixth instrument having an apical diameter of 0.20 mm, wherein the sixth instrument includes two conical sections having a first conicity of 8% for a distance of 4 mm along an active length of the sixth instrument, and a second conicity of 3% along remaining portions of the active length; and a seventh instrument having an apical diameter of 0.20 mm, wherein the seventh instrument includes two conical sections having a first conicity of 10% for a distance of 4 mm along an active length of the seventh instrument, and a second conicity of 2% along remaining portions of the active length.