JP2021061993A - 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 reduced from a base end part over a tip part, and a node 122 between the first and second linear parts 112-113 and a node 123 between the second and third linear parts 113-114 are positioned on the furthermore inside than the virtual circle 101, and an angle A11 formed between a diameter passing a node 121 and the first linear part 112 is set large from the base end part over the tip part.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 and the connection point between the second linear portion and the third linear portion are located inside the virtual circle. Set,
It is characterized in that the diameter formed by the diameter passing through the connection point between the arcuate portion and the first linear portion and the angle formed by the first linear portion are set large from the base end portion to the tip end portion. ..

As a result, for example, when the dental file rotates from the arcuate portion to the first linear portion, the cutting is performed mainly on the arcuate portion and the first line while the arcuate portion is along the inner surface of the cutting hole. It is performed by the connection point with the shape portion, and the angle formed by the diameter passing through the connection point between the arcuate portion and the first linear portion and the first linear portion is from the base end portion to the tip end portion. By setting a large value toward the base end, for example, it is possible to improve the cutting performance, the discharge performance, and the flexibility toward the base end portion while suppressing the cutting force near the tip end.

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

It is a plan view of the dental file of Embodiment 1. 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. FIG. 3 is a cross-sectional equivalent view taken along line III-III of FIG. 1 in the second embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments and modifications, components having similar functions are designated by the same reference numerals and description thereof will be omitted.

(Embodiment 1)
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 is often used, but the material is not limited to this, and stainless steel materials, various alloys, and plastics are used. Etc. may also be applied.

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 shape is formed in a spiral shape. 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 and the connection point 123 between the second linear portion 113 and the third linear portion 114 are the virtual circle 101. It is set to be located inside. Further, although not particularly limited, for example, the first linear portion 112 and the third linear portion 114 are formed in parallel with 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, the arcuate portion 111 and The connection point 121 with the first linear portion 112 causes a cutting action as the dental file 100 rotates. 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, the angles A11 and A12 formed by 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 first linear portion 112 are angles (angles at the tip portion). For example, A11) is set to be larger than the angle at the base end (for example, A12). The size of the absolute angles A11 and A12 is not particularly limited, but is set in the range of, for example, 10 ° to 40 °.

In the setting of the angles A11 and A12 as described above, for example, the relative distance (distance ratio) from the center O of the virtual circle 101 to the first linear portion 112 with respect to the diameter of the virtual circle 101 is set at the tip portion. This can be done by setting the distance L11 of the above to be longer than the distance L21 at the proximal end.

Further, although it is not equivalent to the above setting, it actually defines the ratio of the distances L21 and L22 between the first linear portion 112 and the third linear portion 114 with respect to the diameter of the virtual circle 101. It can also be set by. That is, for example, the cross-sectional shape of the dental file 100 is line-symmetrical with respect to the straight line passing through the center O of the virtual circle 101, and the first linear portion 112 and the third linear portion 114 are formed in parallel. In the case, the ratio of the distances L21 and L22 between the first linear portion 112 and the third linear portion 114 with respect to the diameter of the virtual circle 101 is from the base end portion to the tip end portion of the dental file 100. It may be set large. Further, the central angles A21 and A22 corresponding to the arcuate portion 111 may be set large from the base end portion to the tip end portion of the dental file 100.

As a result, it becomes easy to exert an effect on improving the followability at a stage where the cutting force near the tip is desired to be slightly suppressed (initial stage of root canal formation, etc.) or at a root canal where the vicinity of the apex is bent. Further, the cutting performance and the discharging performance are improved toward the shank portion, and the flexibility is also improved toward the shank portion, so that both machinability and operability can be achieved. Further, there is a so-called "stiffness" near the tip, which makes it easy to improve the rotational transmission force.

(Embodiment 2)
The same angle relationship as the angles A11 and A12 between the tip and the base of the dental file 100 as described above can be set by forming the cross-sectional shape at the base as shown in FIG. .. That is, the angle formed by the perpendicular line drawn from the center O of the arcuate portion 111 to the first linear portion 112 and the perpendicular line drawn down to the third linear portion 114 (the angle on the arcuate portion 111 side) is the tip. The angle A31 at the portion is set to be smaller than the angle A33 at the proximal end portion. As a result, the angles A11 and A13 formed by 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 first linear portion 112 are the angles at the tip portion. (For example, A11) can be set to be larger than the angle at the base end (for example, A13).

As a result, not only can an appropriate cutting performance be obtained at the stage where you want to suppress the cutting force near the tip a little (initial stage of root canal formation, etc.), but it is also effective in the finishing stage and cases where the overall cutting force is required. It becomes easy to exert. In addition, it is possible to increase the cutting force over the shank while providing high followability to the bent root canal. Further, the cutting performance and the discharging performance are improved toward the shank portion, and the flexibility is also improved toward the shank portion, so that it is possible to achieve both machinability and operability.

(Other matters)
In the cross-sectional shape of the dental file 100 as described above, the distances from the center O of the virtual circle 101 to two or more of the first to third linear portions 112 to 114 are set to be equal to each other, or these lines. The shaped portions 112 to 114 may be made to be in contact with the same inscribed circle having the same center as the center O of the virtual circle 101. 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.

100 Dental file 100a Working part 100b Shaft 101 Virtual circle 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 and the connection point between the second linear portion and the third linear portion are located inside the virtual circle. Set,
It is characterized in that the diameter formed by the diameter passing through the connection point between the arcuate portion and the first linear portion and the angle formed by the first linear portion are set large from the base end portion to the tip end portion. Dental file. The dental file of claim 1.
A dental file characterized in that the ratio of the distance from the center of the virtual circle to the first linear portion with respect to the diameter of the virtual circle is set large from the base end portion to the tip end portion. The dental file of claim 2.
The first linear portion and the third linear portion are formed in parallel, and the distance between the first linear portion and the third linear portion with respect to the diameter of the virtual circle. A dental file characterized in that the ratio is set large from the base end portion to the tip end portion. The dental file of claim 2.
A perpendicular line drawn from the center of the virtual circle to the first linear portion,
A dental file characterized in that the angle on the arcuate side formed by a perpendicular line drawn from the center of the virtual circle to the third linear portion is set small from the base end portion to the tip end portion. .. The dental file of claim 1.
A dental file characterized in that the central angle corresponding to the arcuate portion is set large from the base end portion to the tip end portion.
The dental file of claim 1.
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.

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