A dental file includes a working portion having a spiral shape, wherein a cross section perpendicular to a longitudinal direction of the working portion has a trapezoidal shape including an upper bottom, a lower bottom, and first and second oblique sides, vertexes at both ends of the lower bottom are located on an imaginary circle having a center at an axis in the longitudinal direction of the working portion, vertexes at both ends of the upper bottom are located inside the imaginary circle, and the imaginary circle has a diameter decreasing from a base end portion toward a leading end portion of the working portion.

Endodontic instruments for use in performing root canal therapy on a tooth are disclosed. In one form, the instruments include an elongate shank having a cutting edge extending from a distal end of the shank along an axial length of the shank. The shank comprises a titanium alloy, and the shank is prepared by heat-treating the shank at a temperature above 25° C. in an atmosphere consisting essentially of a gas unreactive with the shank. In another form, the endodontic instruments have an elongate shank having a cutting edge extending from a distal end of the shank along an axial length of the shank. The shank consists essentially of a titanium alloy selected from alpha-titanium alloys, beta-titanium alloys, and alpha-beta-titanium alloys. The instruments solve the problems encountered when cleaning and enlarging a curved root canal.

Endodontic instruments for use in performing root canal therapy on a tooth are disclosed. In one form, the instruments include an elongate shank having a cutting edge extending from a distal end of the shank along an axial length of the shank. The shank comprises a titanium alloy, and the shank is prepared by heat-treating the shank at a temperature above 25° C. in an atmosphere consisting essentially of a gas unreactive with the shank. In another form, the endodontic instruments have an elongate shank having a cutting edge extending from a distal end of the shank along an axial length of the shank. The shank consists essentially of a titanium alloy selected from alpha-titanium alloys, beta-titanium alloys, and alpha-beta-titanium alloys. The instruments solve the problems encountered when cleaning and enlarging a curved root canal.

Disclosed is a digital measurement apparatus including a mounting part on which a measurement object is placed; and a measuring part for measuring the length of the measurement object and providing the measurement value of the measured measurement object as a reference value for adjusting the length of a new measurement object, wherein the measuring part measures the length of the measurement object using any one selected from among a moving method of converting a distance moved due to interference with the measurement object placed on the mounting part; a radiation method of radiating a measurement signal toward the measurement object and converting information of the detected measurement signal into the length of the measurement object; and a scanning method of scanning the measurement object. With this configuration, accuracy in measuring the length of a measurement object may be improved using a simple structure.

An endodontic instrument (20) for drilling root a canal within a tooth. The instrument has a working area (21) that is arranged so as to form, shape and/or cut the inner wall of the root canal. The instrument has a plurality of flutes wound around a central axis in the form of a spiral, within a conical envelope (25) so as to have a cross-section that becomes narrower from a first end (23) to the second end (26) of the instrument. The working area (21) is sub-divided into adjacent segments (13) such that the flutes alternately have a straight section and a section that is twisted in the form of a spiral and are arranged, in such a way, that the edges of the flutes are located either on the conical envelope (25) or inside the envelope on the straight sections or on the twisted sections.

An endodontic instrument (20) for drilling root a canal within a tooth. The instrument has a working area (21) that is arranged so as to form, shape and/or cut the inner wall of the root canal. The instrument has a plurality of flutes wound around a central axis in the form of a spiral, within a conical envelope (25) so as to have a cross-section that becomes narrower from a first end (23) to the second end (26) of the instrument. The working area (21) is sub-divided into adjacent segments (13) such that the flutes alternately have a straight section and a section that is twisted in the form of a spiral and are arranged, in such a way, that the edges of the flutes are located either on the conical envelope (25) or inside the envelope on the straight sections or on the twisted sections.

A reciprocating endodontic hand tool in which the torque applied to an instrument such as a debriding file can be set at or below an endurance limit of the file below which failure of the instrument will not occur. In preferred embodiments the tool can switch between settings in which the torque applied to the instrument is between the endurance limit of the file and an elastic limit of the file, by setting forward and reverse angles of rotation within specified limits. This reduces or eliminates opportunities for plastic distortion, fatigue and breakage of the file during the canal debriding/cleaning/shaping process in a root canal treatment or retreatment. In some embodiments the torque may be set to at or below a durability limit of the file below which failure of the instrument will not occur through repetitive strain over the course of a particular root canal treatment or retreatment.

A reciprocating endodontic hand tool in which the torque applied to an instrument such as a debriding file can be set at or below an endurance limit of the file below which failure of the instrument will not occur. In preferred embodiments the tool can switch between settings in which the torque applied to the instrument is between the endurance limit of the file and an elastic limit of the file, by setting forward and reverse angles of rotation within specified limits. This reduces or eliminates opportunities for plastic distortion, fatigue and breakage of the file during the canal debriding/cleaning/shaping process in a root canal treatment or retreatment. In some embodiments the torque may be set to at or below a durability limit of the file below which failure of the instrument will not occur through repetitive strain over the course of a particular root canal treatment or retreatment.

The present invention relates to a kit comprising

an endodontic instrument in the form of an endodontic file and
a container with a lower container part, for receiving the working section (3c) of the endodontic instrument, and an upper container part, for receiving the upper axial end region of the instrument,
wherein a holder is provided on the upper side of the lower container part, which holder comprises an axial through-opening through which the working section of the instrument is inserted into the lower container part and in which the instrument, in particular the tool shaft of the instrument, is fixed in a clamping manner,
wherein the upper container part is connected with the lower container part in an airtight manner to form the container, and the interior of the container and the instrument are sterile.

In a dental treatment apparatus, a control circuit controls a drive motor in accordance with a drive sequence. The drive sequence includes a plurality of drive patterns and at least one of the plurality of drive patterns is different from other drive pattern. The plurality of drive patterns include at least one drive pattern having such drive that a cutting tool is rotated in a cutting direction for cutting a treatment portion and drive for rotating the cutting tool in a non-cutting direction which is reverse to the cutting direction.