An endodontic file for dental nerve treatment according to the present invention comprises: a helical shaped blade that is to be inserted into a root canal, remove dental nerve, and enlarge the root canal; a head that is detachably inserted into a rotary power tool, and a connection part extending by a predetermined length between the head and the blade and having a diameter smaller than that of each of a contact end of the blade and the head. According to the endodontic file for dental nerve treatment, by forming the connection part of the endodontic file with an adjusted thickness or shape such as a thin thickness so that stress generated during rotation of the endodontic file is concentrated on the connection part rather than the blade, the endodontic file is induced to be fractured outside the tooth rather than inside the tooth root, thereby allowing fractured pieces to be easily found and removed.

Provided is a dental file with excellent flexibility, cutting performance, and fracture resistance. The dental file (10) of the present invention has a spiral working portion (11) of which cross sections become smaller toward a tip end. At least one of shapes of the cross sections of the working portion (11) is a substantially rectangular shape formed of a single arc (40) and three lines (41, 42, 43), Two points of four points at four corners of the substantially rectangular shape are arranged on a virtual circle (50), which includes the arc (40) as part thereof. The other two points are arranged inside the virtual circle (50). The center position of the virtual circle (50) is inside the substantially rectangular shape. A shortest one of lengths of perpendicular lines each extending from the center position of the virtual circle (50) including the arc (40) as part thereof to the three lines (41, 42, 43) is equal to or greater than 45% and equal to or less than 65% of the radius of the virtual circle (50).

Provided is a dental file with excellent flexibility, cutting performance, and fracture resistance. The dental file (10) of the present invention has a spiral working portion (11) of which cross sections become smaller toward a tip end. At least one of shapes of the cross sections of the working portion (11) is a substantially rectangular shape formed of a single arc (40) and three lines (41, 42, 43), Two points of four points at four corners of the substantially rectangular shape are arranged on a virtual circle (50), which includes the arc (40) as part thereof. The other two points are arranged inside the virtual circle (50). The center position of the virtual circle (50) is inside the substantially rectangular shape. A shortest one of lengths of perpendicular lines each extending from the center position of the virtual circle (50) including the arc (40) as part thereof to the three lines (41, 42, 43) is equal to or greater than 45% and equal to or less than 65% of the radius of the virtual circle (50).

Endodontic instruments are described which have at least a section with a center of mass offset from an axis of rotation so that when the instrument is rotated, the section bends away from the axis of rotation.

Endodontic instruments are described which have at least a section with a center of mass offset from an axis of rotation so that when the instrument is rotated, the section bends away from the axis of rotation.

A dental tool or instrument having a shank located adjacent a first end thereof and a working area located adjacent an opposite second end. At least one elongate cut is formed along the working area and a memorized shape, having at least one protrusion, is formed in the working area. The dental tool or instrument is manufactured from a nitinol wire which initially has a transition temperature that is below room temperature, while the dental tool or instrument, following manufacture, has a final transition temperature of about 90.5±4 degrees Fahrenheit (i.e., 32.5±3 degrees Celsius). When the dental tool or instrument is at a temperature below its final transition temperature, the dental tool instrument is moldable to facilitate insertion into a root canal, but as soon as the dental tool or instrument is at or above the final transition temperature, the dental tool instrument automatically adopts the memorized shape.

A dental tool or instrument having a shank located adjacent a first end thereof and a working area located adjacent an opposite second end. At least one elongate cut is formed along the working area and a memorized shape, having at least one protrusion, is formed in the working area. The dental tool or instrument is manufactured from a nitinol wire which initially has a transition temperature that is below room temperature, while the dental tool or instrument, following manufacture, has a final transition temperature of about 90.5±4 degrees Fahrenheit (i.e., 32.5±3 degrees Celsius). When the dental tool or instrument is at a temperature below its final transition temperature, the dental tool instrument is moldable to facilitate insertion into a root canal, but as soon as the dental tool or instrument is at or above the final transition temperature, the dental tool instrument automatically adopts the memorized shape.

Instruments to bypass fragments of fractured endodontic rotary files are configured for bypassing fractured fragments of endodontic rotary files that have become lodged within a root canal of a tooth during a root canal treatment. An instrument can be an endodontic file having a handle and a working shaft. The active distal portion of which includes a flat, therefore inactive, lateral surface 3. The files have a dual design along the active distal portion with a safe side and a cutting side to ease the penetration of the instrument in the narrow space between the root canal wall and the broken fragment of a NiTi endodontic rotary file.

Instruments to bypass fragments of fractured endodontic rotary files are configured for bypassing fractured fragments of endodontic rotary files that have become lodged within a root canal of a tooth during a root canal treatment. An instrument can be an endodontic file having a handle and a working shaft. The active distal portion of which includes a flat, therefore inactive, lateral surface 3. The files have a dual design along the active distal portion with a safe side and a cutting side to ease the penetration of the instrument in the narrow space between the root canal wall and the broken fragment of a NiTi endodontic rotary file.

Endodontic instruments are described which have at least a section with a center of mass offset from an axis of rotation so that when the instrument is rotated, the section bends away from the axis of rotation.