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.

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 used to clean and enlarge the endodontic cavity space (ECS), also known as the root canal system, of a human tooth. This document describes novel endodontic instruments that are radially compressible, and methods for their use. Some embodiments include a shank and a body with a working surface. At least a portion of the working surface may define a center of mass path that spirals. The center of mass of a transverse cross-section of the working surface at the shank end can be offset from the axis of rotation of the instrument.

Endodontic instruments are used to clean and enlarge the endodontic cavity space (ECS), also known as the root canal system, of a human tooth. This document describes novel endodontic instruments that are radially compressible, and methods for their use. Some embodiments include a shank and a body with a working surface. At least a portion of the working surface may define a center of mass path that spirals. The center of mass of a transverse cross-section of the working surface at the shank end can be offset from the axis of rotation of the instrument.

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.

The invention relates to a root canal instrument (10) having a blade comprising a plurality of helical cutting edges (20), the blade being conical in shape and extending from a tip (11) towards a mandrel (12) of the instrument, the helical edges (20) having a pitch increasing along a longitudinal axis of the instrument from the tip (11) towards the mandrel (12).

According to the invention, it comprises a ratio between the pitch at the mandrel (12) and the pitch of the end of the tip (11), of between 2 and 4.

The invention relates to a root canal instrument (10) having a blade comprising a plurality of helical cutting edges (20), the blade being conical in shape and extending from a tip (11) towards a mandrel (12) of the instrument, the helical edges (20) having a pitch increasing along a longitudinal axis of the instrument from the tip (11) towards the mandrel (12).

According to the invention, it comprises a ratio between the pitch at the mandrel (12) and the pitch of the end of the tip (11), of between 2 and 4.

An endodontic instrument of this disclosure has less torque strength but greater flexibility and enlarged chip space compared to the prior art. In embodiments. only two flutes are spiraled about the instrument's length L to form two non-landed cutting edges between D2 and D16, the cutting edges merging to form a land at about D1. The tip end is rounded. The helical angle α increases from the handle end toward the tip end, a number of spirals per unit length being at least two times greater toward the tip end than toward the handle end, a cross-section of the length L consisting of two convex portions intersecting at each cutting edge or a wave-shape having one concave portion and one convex portion intersecting at each cutting edge, the cross-section occupying less total area than would a same size endodontic instrument having a triangular cross-section and providing greater chip space.

An endodontic instrument of this disclosure has less torque strength but greater flexibility and enlarged chip space compared to the prior art. In embodiments. only two flutes are spiraled about the instrument's length L to form two non-landed cutting edges between D2 and D16, the cutting edges merging to form a land at about D1. The tip end is rounded. The helical angle α increases from the handle end toward the tip end, a number of spirals per unit length being at least two times greater toward the tip end than toward the handle end, a cross-section of the length L consisting of two convex portions intersecting at each cutting edge or a wave-shape having one concave portion and one convex portion intersecting at each cutting edge, the cross-section occupying less total area than would a same size endodontic instrument having a triangular cross-section and providing greater chip space.