JPS5816893B2 - root canal file - Google Patents

Description

[Detailed description of the invention] Specification The present invention relates to a root canal file.

Root canal files are used by dentists in root canal treatment to dilate the root canal.

Three types of such files are known in the art.

The so-called Hedstrom file or H-file is manufactured by forming a spiral groove 3 having a special shape as shown in FIGS. 1 and 2 in a tapered file blank, so that the groove The outer edge forms the helical cutting edge 2 of the file.

The other two types of conventionally known files, the so-called one file and the so-called one reamer (root canal dilator) (hereinafter referred to as both types of files), are first a file blank rectangular cross section or After grinding to a triangular cross-section, the file blank is twisted so that the edges of the square or triangular file blank form cutting edges that extend helically around the circumference of the file.

It is also possible that the file is ground to a helical cross section.

The previously known files mentioned above have various features and partially different functions, and when cutting a root canal it is often necessary to use both files.

The frangible shape of the so-called single file forms a thin, light and flexible root canal instrument used as an "opener".

The K-file is inserted into the root canal by a helical motion.

However, the cutting edge of the file is not extremely sharp, and the file's ability to remove substances is small.

Therefore, so-called H-files are used to widen the root canal after a small passageway has been created in the root canal by means of the K-files.

Although the H-file has a great ability to remove substances in the root canal, it is difficult to find the passageway in the root canal unless it is prepared by one file.

The object of the present invention is to provide a new type of root canal file designed to replace the previously known files mentioned above.

The object of the present invention is that the actuating part has two continuous cutting edges extending spirally along the actuating part, and these cutting edges are offset from each other in the longitudinal direction of the actuating part, As a result, each turn of one marking line is achieved by a root canal file located between two mutually consecutive turns of another cutting edge marking line.

In the root canal file of the present invention, two continuous grooves extending spirally are ground on the outer surface of the file blank, and these grooves are offset from each other in the longitudinal direction of the file blank. As a result, each one marked turn of one groove is located between two mutually continuous marked turns of another groove, and the outer edge of the groove spirals along the file blank. Two continuous cutting edges are formed which extend in a shape, and these cutting edges are offset from each other along the longitudinal direction of the file blank.

Therefore, according to the present invention, there is provided a root canal file that on the one hand has the flexibility and strength to be inserted into a curved tooth root canal without breaking, and on the other hand has a high ability to remove substances from the root canal. .

A detailed description of the invention will now be provided with reference to representative embodiments of the root canal file of the invention shown in FIGS. 3-8 of the drawings.

FIG. 1 shows the operating part of the conventionally known root canal file as described above, and FIG. 2 shows a part of the operating part of the conventionally known root canal file as described above. 3 is an enlarged partial cross-sectional view through the longitudinal axis and a cross-sectional view of the working part through the plane B-B, FIG. 3 is a specific example of the working part of the root canal file of the present invention, and FIG. 4 is the working part of FIG. 3. Part 1 of the
An enlarged partial sectional view along the longitudinal axis of the root canal file and a sectional view of the working part through the plane A-A, FIG. 5 an enlarged view of a part of the working part of FIG. 3, and FIG. 6 a root canal A sectional view of a part of the working part of FIG. 3 along the longitudinal axis of the file, FIG. 7 an enlarged view of a part of FIG. 6, and FIG. 8 a schematic diagram of the working part of the root canal file of the invention. It is a diagram.

The root canal file of the invention shown in Figures 3-8 is produced by grinding two grooves 4, 6 extending helically along a tapered file blank.

See Figures 3 and 4.

The grooves are offset with respect to each other in the longitudinal direction of the file blank, so that each one marked turn of one groove lies between two mutually consecutive marked turns of another groove. and the entrances of the grooves at the tip of the actuating portion are arranged at diametrically opposite points.

That is, they are shifted by 180° with respect to each other.

Furthermore, as shown in FIGS. 3, 4 and 7, the groove is designed to form two continuous helical edges 8, 10.

These index lines are therefore offset relative to each other along the longitudinal direction of the file, so that each turn of one index line is a continuation of each other of another index line. It is located between two turns.

The so-called H-file known in the art, shown in FIGS. 1 and 2, has only one helically extending cutting edge 2. The so-called H-file shown in FIGS.

The cutting edge of the file of the present invention and H- shown in FIGS. 1 and 2.
When the axial distance between the cutting edges of the file is the same, the pitch of the cutting edge marking lines 8 and 10 of the file of the present invention (and the distance between the cutting edges) The helical groove pitch of 4°6) is twice as large as the pitch of the only one marked line of the H-file.

Thus, the files of the present invention can be designed with relatively large pitch grooves and cutting edges so that they are soft and flexible and can be easily inserted into curved root canals without fear of breaking or cracking.

Furthermore, as a result of the large pitch, material scraped within the root canal is efficiently transported out of the root canal by rotation of the file.

As a result, the file acquires a large material removal capacity.

In FIG. 2, part of the working part of a so-called H-file is shown in a partial sectional view along the longitudinal axis and in a sectional view perpendicular to the longitudinal axis.

According to the figure, this conventionally known file has the code 14.
, 16 are staggered with respect to each other.

Conversely, in the file of the present invention, the first and second helical cutting edges are positioned diametrically opposite each other at each axial position, as shown particularly clearly in FIGS. 6 and 7. are doing.

This reduces the risk of the file breaking during use.
The improved strength thus obtained with the files of the invention allows the core to be made considerably thinner, i.e. with deeper grooves.

This leaves more space in the groove between the cutting edges to remove scraped material.

Therefore, the material removal ability of the file is improved and the file is more efficient.

The working part of the root canal file of the present invention is typically conical.

FIG. 8 schematically shows the operating part of the file of the invention.

In the figure, generatrix 18.2 of a cone surrounding the working part of the file.
0 is extended at their intersection point 22.

That is, the apex of the cone is located at point 22.

The distance between the apex 22 of the cone and the tip 12 of the working part of the file is indicated by H6, and the distance between the apex 22 of the cone and the tip 12 of the working part of the file is
The distance between the nth marking line of the actuating part counting from 2 is Hn
It is indicated by.

Furthermore, one of the cone angles in said cone is denoted by α.

Furthermore, as shown in Fig. 5, when the angle (cutting angle) between the cutting edge and a line perpendicular to the longitudinal axis of the actuating part is represented by β, the following relationship exists between Hn, H8, n, α, and β. The relationship holds true.

H=Ho, 1 n ”2 yr °sin α °tan
The cutting angle β can be changed by making the groove between the β cutting edges deeper or shallower.

That is, files with larger cores or files with smaller cores are formed because the cutting angle is greater for files with larger cores than for files with smaller cores.

As a result, the angle β can be changed by changing the depth of the grooves in the file.

In summary, the files of the present invention are oriented 180° with respect to each other.
At each level along the longitudinal direction the file contains two helical cutting edges manufactured by grinding two helical grooves with a deviation of IJ - the smallest mutual It is ensured that the blade has two working cutting edges located opposite to each other.

This way the file is formed with a thinner core,
Moreover, it can resist stress during use.

The thin core of the file, together with the large pitch of its cutting edges or grooves between the cutting edges, makes it soft and flexible, so that it can be easily inserted into curved root canals.

The combination of the deep grooves between the cutting edges (i.e., thin core) and the large pitch of the grooves further increases the file's ability to effectively remove material from between the roots that has been scraped away by rotating the file.

Claims (1)

[Claims] 1. The actuating part has two continuous cutting edges extending helically along the actuating part with an offset relative to each other in the longitudinal direction of the actuating part, so that one A root canal file in which each turn of the cutting edge marking line is located between two mutually continuous turns of another cutting edge marking line. 2. The file according to claim 1, wherein the cutting edge starts from two points that are diametrically opposed or substantially opposed at the tip of the operating portion. Claim 1 or 2: The pitch of the 32 cutting edge marking lines is equal.
Files listed in. 4. The actuating part has two continuous grooves spirally extending in the longitudinal direction of the actuating part. 5. The file according to claim 1, wherein the outer edge of the groove forms two continuous cutting edges. 6. The file according to claim 5, wherein the two spiral grooves are formed at equal pitches.