JP2021061994A - Dental file - Google Patents

Abstract

To provide a dental file having high flexibility, machinability and/or break resistance.SOLUTION: In a dental file 100, a cross-sectional shape is constituted of an arc-shaped part 111, and first to third linear parts 112-114 connecting therefrom successively, and a diameter of a virtual circle 101 including the arc-shaped part 111 is set small from a base end part over a tip part, and a node 122 between the first linear part 112 and the second linear part 113 is set so as to be positioned on the virtual circle 101, and a node 123 between the second linear part 113 and the third linear part 114 is positioned on the furthermore inside than the virtual circle 101.SELECTED DRAWING: Figure 2

Description

The present invention relates to a dental file used for root canal enlargement and cleaning in dental treatment.

Reamers and files are examples of dental root canal cutting tools used for enlarging and cleaning root canals in dental treatment (see, for example, Patent Document 1). The reamer mainly cuts the inside of the root canal by rotating it, and the file cuts the inside of the root canal by rotating it or pushing and pulling it in the axial direction.

Some general dental files are used by gripping the grip portion by hand, and some are used by connecting the grip portion to the dental handpiece. The dental file has a working portion spirally shaped to taper toward the tip, a shaft connected to the rear end of the working portion, and a grip portion connected to the rear end of the shaft. The main performance required for such a dental file is the flexibility to follow a root canal with a complicated shape, the machinability to cut the root canal properly, and the fracture resistance that does not break during work. And so on. The higher these performances, the easier and faster the root canal formation can be performed, and the burden on the practitioner and the patient can be reduced.

Japanese Unexamined Patent Publication No. 2005-278945

In view of the above circumstances, an object of the present invention is to increase the flexibility, machinability, and / or fracture resistance of a dental file.

In order to achieve the above object, the present invention
A dental file with a spirally formed working part
The cross-sectional shape of the cross section perpendicular to the longitudinal direction is composed of one arcuate portion and three first to third linear portions sequentially continuous from the arcuate portion, and the base end portion to the tip end portion. The diameter of the virtual circle including the arcuate portion is set small, and the diameter is set small.
The connection point between the first linear portion and the second linear portion is set so as to be located on the virtual circle.
The connection point between the second linear portion and the third linear portion is set to be located inside the virtual circle.

Thereby, for example, when the dental file rotates from the arcuate portion to the first linear portion, the cutting is performed in addition to the connection point between the arcuate portion and the first linear portion. Since it is performed by the connection point between the linear portion and the second linear portion, the cutting ability can be easily maintained high. On the other hand, the connection point between the first linear portion and the second linear portion is not on the diagonal of the connection point between the arcuate portion and the first linear portion. It is possible to easily prevent rapid rotation stop and the like, and to prevent breakage due to impact.

According to the present invention, the flexibility, machinability, and / or fracture resistance of dental files can be increased.

It is a plan view of a dental file. FIG. 2 is a cross-sectional view taken along the line II-II of FIG. FIG. 3 is a cross-sectional view taken along the line III-III of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the dental file 100 is attached to the dental handpiece, which is connected to the working portion 100a for cutting the root canal, the shaft 100b connected to the rear end of the working portion 100a, and the rear end of the shaft 100b. It has a grip portion (not shown). As the material of the dental file 100, for example, nickel titanium having high elasticity suitable for treating a complicatedly curved root canal or the like is used.

The working portion 100a of the dental file 100 has a structure in which the envelope surface of the outer surface has a tapered shape in which the cross section becomes smaller toward the tip, and the cross section having a similar or similar shape is formed in a spiral shape. There is. More specifically, the cross-sectional shape of the cross section of the working portion 100a perpendicular to the longitudinal direction is formed, for example, as shown in FIG. 1 or the cross-sectional view taken along the line II-II or the cross-sectional view taken along the line III-III. There is. That is, the cross-sectional shape is composed of one arcuate portion 111 (land portion) and three first to third linear portions 112 to 114 sequentially continuous from the arcuate portion 111, and works. From the base end portion to the tip end portion of the portion 100a, the diameter of the virtual circle 101 including the arc-shaped portion 111 and the center is set to be small. The linear portions 112 to 114 do not necessarily have to be an accurate straight line, and even if they are slightly curved, for example, the effects described below can be obtained. Here, in FIGS. 2 and 3, for convenience, they are drawn on a scale so that the diameters of the virtual circles 101 are equal.

The connection point 122 between the first linear portion 112 and the second linear portion 113 is set to be located on the virtual circle 101. Further, the connection point 123 between the second linear portion 113 and the third linear portion 114 is set to be located inside the virtual circle 101. Further, although not particularly limited, for example, the first linear portion 112 and the third linear portion 114 are formed perpendicular to the chord 103 corresponding to the arcuate portion 111 and parallel to each other. As a result, it becomes easy to facilitate the blade groove grinding process and to improve the blade groove grinding process accuracy.

Here, let the rotation direction in which the cutting chips in the working portion 100a are carried toward the base portion be the main rotation direction R in the normal use of the dental file 100, that is, specifically, for example, for example. When the spiral of the dental file 100 is a right-handed screw, assuming that the rotation direction R is mainly counterclockwise when viewed from the tip side, when rotating in such an R direction, it is virtual as described above. By providing the two connection points 121 and the connection points 122 located on the circle 101, the cutting ability can be easily maintained high by performing the cutting by these. On the other hand, the connection point 122 is located at a position offset from the diameter passing through the connection point 121, and the connection point 123 diagonally opposite to the connection point 121 is inside the virtual circle 101. Rotation stop (lock) and the like are unlikely to occur, and therefore, breakage due to an impact due to the lock can be less likely to occur. The rotation direction of the dental file 100 is not limited to the R direction, and may be used in a mode including reverse rotation or a mode in which the rotation direction changes alternately.

Further, since the connection point 123 between the second linear portion 113 and the third linear portion 114 is provided as described above, the first linear portion 112 and the second linear portion 113 are provided. While setting the angles A21 and A22 formed by the diameter passing through the connection point 122 and the second linear portion 113 to some extent, the length of the arcuate portion 111 is not too long due to the third linear portion 114. Can be easily set to. Therefore, the angles A21 and A22 are set to a certain size to prevent pulling in and impact fracture due to locking, and the arcuate portion 111 is not too long to improve followability and flexibility. It is easy to prevent fatigue fracture from occurring.

Further, the connection point 121 between the arcuate portion 111 and the first linear portion 112 is more connected to the main dental file than the connection point 122 between the first linear portion 112 and the second linear portion 113. It is set to be located on the upstream side of the rotation direction R. Further, in the case of the relationship between the cross-sectional shape and the main rotation direction as described above, the arcuate portion 111 and the arcuate portion 111 are formed on the side portion of the working portion 100a extending from the tip end portion to the base end portion of the dental file 100. The first to third linear portions 112 to 114 are formed so as to appear in order. In the case of such a relationship between the cross-sectional shape and the rotation direction, as the dental file 100 rotates, following the cutting by the connection point 121 at the downstream end of the main rotation direction R in the arcuate portion 111, the virtual portion 111 is virtual. By cutting at the connection point 122 located on the circle 101, it is possible to easily maintain a high cutting ability.

Further, although not particularly limited, for example, the diameter of the virtual circle 101 passing through the connection point 121 between the arcuate portion 111 and the first linear portion 112 and the angles A11 and A12 formed by the first linear portion 112. , The diameter of the virtual circle 101 passing through the connection point 122 between the first linear portion 112 and the second linear portion 113 and the angles A21 and A22 formed by the second linear portion 113 are set to be equal to each other. Has been done. More specifically, for example, each is set to 10 ° or more and 40 ° or less, preferably about 30 ° or the like. Usually, it is easy to set an appropriate cutting ability within such an angle range.

Here, instead of setting the angle as described above, the dimensions of each part can be specified. That is, for example, the distances from the center O of the virtual circle 101 to the first to third linear portions 112 to 114 are set to be equal to each other, or these linear portions 112 to 114 touch the same inscribed circle 102. May be done. Such a shape can be easily formed by equalizing the amount of cutting from the outer circumference of the virtual circle 101 to each of the linear portions 112 to 114. For example, in a program for operating a grinding machine, a predetermined amount of cutting can be formed. Grinding can be easily performed by using the above routines in common.

The cross-sectional shape as described above may be formed in a similar shape over the entire length or a part of the working portion 100a in the longitudinal direction, but may be formed in a shape that changes as shown in FIGS. 2 and 3. .. That is, the angles A11 and A12 formed by the diameter passing through the connection point 121 between the arcuate portion 111 and the first linear portion 112 and the first linear portion 112 are from the base end portion to the tip end portion of the working portion 100a. It is set large toward. Further, the angles A21 and A22 formed by the diameter passing through the connection point 122 between the first linear portion 112 and the second linear portion 113 and the second linear portion 113 are the base end portions of the working portion 100a. It is set large from to the tip. It should be noted that the changes in the angles A11 / A12 and the angles A21 / A22 as described above may be set so that only one of them occurs.

By setting the cross-sectional shape that changes along the longitudinal direction of the dental file 100 in this way, the cutting force near the tip end is kept relatively small, and the cutting force near the base end is set relatively large. can do. Therefore, for example, even when it is used in the initial stage or finishing stage of root canal formation, or in cases where the overall cutting force is required, while ensuring flexibility near the tip and high followability to a bent root canal. It is easily possible to increase the cutting force toward the base end portion. Further, in particular, the ratio of the so-called pocket to the virtual circle 101 is set so that the angles A11 and A12 formed by the diameter passing through the connection point 121 and the first linear portion 112 are set small from the tip end portion to the base end portion. By increasing the number, it becomes easier to discharge cutting chips from the tip to the base, and the ratio of the cross-sectional area (second moment of inertia) to the cross-sectional shape of the virtual circle 101 becomes smaller, which further improves flexibility. It can be easily made to do.

100 Dental file 100a Working part 100b Shaft 101 Virtual circle 102 Inscribed circle 103 String 111 Arc-shaped part 112 First linear part 113 Second linear part 114 Third linear part 121 Connection point 122 Connection point 123 Connection point

Claims (6)

A dental file with a spirally formed working part
The cross-sectional shape of the cross section perpendicular to the longitudinal direction is composed of one arcuate portion and three first to third linear portions sequentially continuous from the arcuate portion, and the base end portion to the tip end portion. The diameter of the virtual circle including the arcuate portion is set small, and the diameter is set small.
The connection point between the first linear portion and the second linear portion is set so as to be located on the virtual circle.
A dental file characterized in that the connection point between the second linear portion and the third linear portion is set to be located inside the virtual circle. The dental file of claim 1.
A dental file characterized in that the first and third linear portions are formed perpendicular to the strings corresponding to the arcuate portions, respectively. The dental file of claim 2.
The diameter of the arc-shaped portion passing through the connection point between the arc-shaped portion and the first linear portion, and the angle formed by the first linear portion.
For dentistry, the diameter passing through the connection point between the first linear portion and the second linear portion and the angle formed by the second linear portion are set to be equal to each other. File. The dental file of claim 2.
A dental file characterized in that the distances from the center of the virtual circle to the first to third linear portions are set to be equal to each other. The dental file of claim 1.
The connection point between the arcuate portion and the first linear portion is upstream of the connection point between the first linear portion and the second linear portion in the main rotation direction of the dental file. A dental file characterized by being located on the side. The dental file of claim 1.
The diameter passing through the connection point between the arcuate portion and the first linear portion, the angle formed by the first linear portion, and the first linear portion and the second linear portion. A dental file characterized in that at least one of the diameter passing through the connection point of the above and the angle formed by the second linear portion is set large from the base end portion to the tip end portion.

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