Endodontic instrument with controlled flexibility and method of manufacturing same

A method of making an endodontic instrument from a wire having an outer surface, a longitudinal axis, a proximal end and a distal end, the method comprising:

• removing material from the outer surface of the wire along at least three separate paths extending along the longitudinal axis to form a working length with adjacent first, second and third lengthwise surface portions,
• forming at least three separate edges extending along the working length and each positioned between two adjacent lengthwise surface portions thereby forming a ground wire blank having a major diameter and a smaller, first minor diameter,
• removing at least a portion of two of the edges to form at least fourth and fifth lengthwise surface portions on generally opposite sides of the longitudinal axis for defining a second minor diameter between the fourth and fifth lengthwise surface portions smaller than the first minor diameter, the fourth and fifth lengthwise surface portions being parallel to each other, and
• twisting at least one of the proximal and distal ends with respect to the other and about the longitudinal axis to form said edges and lengthwise surface portions into helically shared edges and surface portions alone the working length.

An endodontic instrument for removing dental tissue, the instrument comprising:

• an elongate member including a longitudinal axis, a proximal end, a distal end, a major diameter and a smaller, minor diameter and a working length with an outer surface generally located between the proximal and distal ends,
• first, second and third lengthwise extending surface portions each forming part of the outer surface and tapering along the longitudinal axis in a direction from the proximal end toward the distal end, said first, second and third lengthwise extending surface portions forming a generally triangular cross sectional shape,
• a lengthwise extending cutting edge lying along the major diameter and formed at a junction between said first and second lengthwise extending surface portions, and
• a fourth lengthwise extending surface portion lying on the minor diameter and formed at a junction between said first and third lengthwise extending surface portions, each of said first, second, third and fourth lengthwise extending surface portions lying in separate planes.

An endodontic instrument for removing dental tissue, the instrument comprising:

• an elongate member including a longitudinal axis, a proximal end, a distal end, a major diameter and a smaller, minor diameter and a working length with an outer surface generally located between the proximal and distal ends,
• first, second and third lengthwise extending surface portions each forming part of the outer surface and tapering along the longitudinal axis in a direction from the proximal end toward the distal end, said first, second and third lengthwise extending surface portions forming a generally triangular cross sectional shape,
• a lengthwise extending cutting edge lying along the major diameter and formed at a junction between said first and second lengthwise extending surface portions, and
• fourth and fifth lengthwise extending surface portions lying on the minor diameter, said fourth lengthwise extending surface portion formed at a junction between said first and third lengthwise extending surface portions and said fifth lengthwise extending surface portion formed at a junction between said second and third lengthwise extending surface portions, said fourth and fifth lengthwise extending surface portions being parallel to each other.

An endodontic instrument for removing dental tissue, the instrument comprising:

• an elongate member including a longitudinal axis, a proximal end, a distal end, a major diameter and a smaller, minor diameter and a working length with an outer surface generally located between the proximal and distal ends,
• first, second, third and fourth lengthwise extending surface portions each forming part of the outer surface and tapering along the longitudinal axis in a direction from the proximal end toward the distal end, said first, second, third and fourth lengthwise extending surface portions forming a generally parallelogram-shaped cross section,
• a first lengthwise extending cutting edge lying on the major diameter and formed at a junction between said first and second lengthwise extending surface portions,
• a second lengthwise extending cutting edge lying on the major diameter and formed at a junction between said third and fourth lengthwise extending surface portions, and
• a fifth lengthwise extending surface portion having a taper less than the respective tapers of the first, second, third and fourth lengthwise extending surface portions said fifth lengthwise extending surface portion formed at a junction between said second and third lengthwise extending surface portions.