Interdental brush

Abstract

To provide an interdental brush which shows excellent cleaning properties and cleaning feeling for users in a wide range of age groups.SOLUTION: An interdental brush includes a brush part in which a plurality of filaments is tightly held between wires which are folded back and twisted, and a plurality of brush bristles made of the filaments protrudes radially around the wire. At least a part of the filament out of the plurality of the filaments is tightly held between the wires in a position shifting to one side relative to the central position in the lengthwise direction of the filament. As the result, the short brush bristles are formed on one side, and the long brush bristles are formed on the other side.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an interdental brush having a brush part in which a plurality of filaments are sandwiched between folded and twisted wires, and a plurality of brush hairs made of filaments radially protrude around the wires.

Background Art

[0002] Conventionally, this type of interdental brush has been provided in which, after forming the brush part, the outer peripheral part thereof is cut and adjusted to a desired outer shape (see, for example, Patent Document 1). In order to clean deep between teeth with an interdental brush, it is necessary to make the length of the brush hairs somewhat long.

[0003] However, when the hair length is long, the hairs tend to bend, and the cleaning power for cleaning dental plaque and the like adhering between teeth tends to decrease. If the brush hairs are made thicker to suppress bending, although the cleaning power improves, there is a problem that it becomes easier to feel irritation (such as pain) and the cleaning feeling deteriorates. Further, when the hair length of the brush hairs is increased or decreased with a conventional interdental brush, the passing diameter (the size of the gap between teeth into which the interdental brush can be inserted) increases due to the overlapping of the brush hairs when passing between teeth, and there is also a problem that it cannot be used by young users with small gaps between teeth. Even though the length of the hair length can be changed by cutting the outer peripheral part, since the passing diameter is limited by the region where the hair length is long, there has been a problem that it is difficult to provide an interdental brush excellent in cleaning performance and cleaning feeling to a wide range of users.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Therefore, in view of the above situation, the problem to be solved by the present invention is to provide an interdental cleaning tool that is excellent in cleanability and cleaning feeling for users of a wide age range.

Means for Solving the Problems

[0006] In view of such a situation, the inventors of the present invention have conducted intensive studies. First, as a structure that cannot be achieved by the conventional cutting of the outer peripheral portion, if long brush hairs and short brush hairs are alternately arranged adjacent to each other, even if the length and thickness of the brush hairs are increased, the amount of overlap between the brush hairs when passing between teeth can be reduced, and it was conceived that the passing diameter can be suppressed. However, it is an extremely difficult task to automatically arrange long filaments and short filaments alternately between wires. Therefore, as a result of further intensive studies by the inventor of the present invention, even if filaments of the same length are arranged adjacent to each other between wires, if the clamping position of each filament is shifted to one side from the center, short brush hairs are formed on one side of each filament, and long brush hairs are formed on the other side. As a result, a brush hair structure of a long and short double helix arrangement composed of a helix arrangement of long brush hairs and a helix arrangement of short brush hairs is formed. Thereby, similar to the case where long filaments and short filaments are alternately arranged between wires, it was found that long brush hairs and short brush hairs can be alternately arranged adjacent to each other, and the amount of overlap between the brush hairs when passing between teeth can be reduced, and the present invention has been completed.

[0007] That is, the present invention includes the following inventions. (1) An interdental brush provided with a brush portion in which a plurality of filaments are clamped between folded and twisted wires, and a plurality of brush hairs made of the filaments protrude radially around the wires, wherein at least a part of the plurality of filaments is clamped between the wires at a position shifted to one side from the central position in the length direction of the filament, whereby short brush hairs are formed on the one side and long brush hairs are formed on the other side. Here, "long" and "short" indicate the relative length relationship where the brush hairs formed on one side are shorter than those on the other side, and the brush hairs formed on the other side are relatively long. Also, in the present invention, the length of the brush refers to the distance from the center of the twisted (twisted) wire to the tip of the filament constituting the brush when the wire is viewed from the tip side.

[0008] (2) A plurality of filaments continuously arranged in the wire axis direction are clamped at displaced positions on the same said one side, whereby a long-short double spiral arrangement of brush hairs composed of a spiral arrangement of long brush hairs formed by the plurality of filaments and a spiral arrangement of short brush hairs also formed by the plurality of filaments. The interdental brush according to (1) above having a brush hair structure.

[0009] (3) The interdental brush according to (1) or also (2) above, wherein the length of the short brush hairs is 1.0 mm or more.

[0010] (4) The interdental brush according to any one of (1) to (3) above, wherein the ratio of the length of the long brush hairs to the length of the short brush hairs ((length of long brush hairs) / (length of short brush hairs)) formed from the same filament is 12 or less.

[0011] (5) The interdental brush according to any one of (1) to (4) above, wherein at least a part of the filaments are filaments having a tapered portion that tapers towards one end side or both end sides, and the long brush hairs or the short brush hairs formed from the filaments are tapered.

[0012] In placing a plurality of filaments cut to a predetermined length between two-folded wires, at least some of the plurality of filaments are sandwiched between the wires at a position shifted to one side from the central position in the longitudinal direction of the filament, and then, by twisting the wire, short brush bristles are formed on one side around the twisted wire, and long brush bristles are formed on the other side, and a method for manufacturing an interdental brush forming a brush part in which a plurality of brush bristles project radially.

[0013] (7) A plurality of filaments arranged continuously in the wire axis direction are sandwiched at positions shifted to the same one side, whereby a long-short double helix arrangement of brush bristles composed of a helical arrangement of long brush bristles formed by the plurality of filaments and a helical arrangement of short brush bristles formed by the plurality of filaments is formed. The method for manufacturing an interdental brush according to (6) above.

Advantages of the Invention

[0014] According to the present invention, since relatively long brush bristles and relatively short brush bristles are alternately arranged in the longitudinal direction of the twisted wire, the relatively long brush bristles can clean deep between the teeth, and the amount of overlap between the brush bristles when passing between the teeth can be reduced. The passage diameter is not restricted by the length of the bristles, the degree of freedom in design is increased, and an interdental cleaning tool excellent in cleaning performance and cleaning feeling can be provided for users of a wide range of age groups.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

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Figure 6

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Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Embodiments for Carrying Out the Invention

[0016] Next, embodiments of the present invention will be described in detail based on the accompanying drawings.

[0017] As shown in FIGS. 1 to 3, the interdental brush 1 according to the present invention includes a brush part 2 in which a plurality of filaments 3 are sandwiched between folded and twisted wires 4, and a plurality of brush hairs 5a, 5b made of the filaments 3 radially protrude around the wire 4. In particular, as also shown in the enlarged view of FIG. 2, the brush hairs 5a, 5b are sandwiched between the wires 4 at a position where the filaments 3 are displaced to one side from the central position in the length direction, so that short brush hairs 5b are formed on one side and long brush hairs 5a are formed on the other side.

[0018] According to such an interdental brush 1, it is possible to clean deep into the interdental space with the long brush bristles 5a, and the short brush bristles 5b support the long brush bristles 5a, so that it is possible to firmly scrape out dental plaque and the like deep in the interdental space without making the bristles too thick. Also, the combination of the long brush bristles 5a and the short brush bristles 5b can efficiently clean along the complex shape of the interdental space. Furthermore, when passing through the interdental space, the overlapping amount of the brush bristles 5a and 5b adjacent in the wire axis direction is reduced, and the passing diameter is suppressed. Therefore, the design freedom to cope with various passing diameters is improved, and it is possible to provide an interdental cleaning tool excellent in cleanability and cleaning feeling for users of a wide age range.

[0019] The filaments 3 can widely adopt filaments used in conventionally known interdental brushes. For example, they can be synthetic resin monofilaments such as polyamide (nylon), polypropylene, polyethylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), mixtures of these resins, and other synthetic resin products, or natural hairs such as animal hairs, which can be appropriately selected.

[0020] The cross-sectional shape of the filament 3 is not particularly limited. Cross-sectional shapes of filaments used in conventionally known interdental brushes such as a substantially circular shape, a substantially equilateral triangle shape, a substantially rhombus shape, a substantially isosceles triangle shape, a substantially parallelogram shape, and other irregular shapes can be appropriately selected. The "substantially equilateral triangle", "substantially rhombus shape", "substantially isosceles triangle shape", and "substantially parallelogram shape" include those with somewhat rounded corners, somewhat bulging sides, or somewhat concave sides of the respective shapes of an equilateral triangle, a rhombus, an isosceles triangle, and a parallelogram, that is, those having some distortion.

[0021] Also, as shown in Fig. 10, it is preferable that the filament 3 has a tapered portion that tapers towards one end or both ends, and the long brush hairs 5a or short brush hairs 5b formed from the filament 3 are configured to taper. Such a tapered portion can be obtained, for example, by dipping the end of a bundle of filaments in a melting solution or by machining, similar to conventionally known filaments. When using a filament having such a tapered portion, it is preferable to set the position where it is clamped by the wire to a straight portion that is not the tapered portion in terms of maintaining the pulling-out strength.

[0022] Particularly, by forming a tapered portion only at one end and tapering the long brush hairs 5a, the long brush hairs 5a can be made lighter, so that the weight balance between the long brush hairs 5a and the short brush hairs 5b can be set in a balanced direction, and it is preferable in that it can prevent the filaments from shifting further towards the long brush hairs 5a due to centrifugal force when the wire is twisted during manufacturing.

[0023] Regarding the wire 4 as well, any wire conventionally known for use in interdental brushes can be widely adopted. An example of the material constituting the wire is stainless steel, ferritic stainless steel, austenitic stainless steel, austenite-ferrite stainless steel, martensitic stainless steel, precipitation-hardening stainless steel, nickel-based alloy, cobalt-based alloy, or titanium-nickel alloy. The diameter of the wire is not particularly limited and can be appropriately set, for example, to about 0.20 to 0.45 mm. Also, those coated with a resin material such as urethane may be used.

[0024] In the interdental brush 1 of this example, a rod-shaped handle portion 6 for embedding and holding the wire base is provided on the proximal end side of the brush portion 2. In this example, the brush portion 2 and the handle portion 6 are provided coaxially, but various forms are possible, such as an L-shaped one in which the brush portion 2 projects laterally from the tip of the handle portion 6, or one in which the brush portion 2 is configured to be detachably replaceable with respect to the handle portion 6.

[0025] In this embodiment, as shown in FIGS. 3(a) and 3(b), a plurality of filaments 3 arranged continuously in the axial direction of the wire 4 are clamped at positions shifted to the same one side, whereby a long brush hair 5a formed by the plurality of filaments 3 has a spiral arrangement 5A, and a short brush hair 5b also formed by the plurality of filaments 3 has a spiral arrangement 5B, and it has a brush hair structure with a long and short double spiral arrangement.

[0026] However, the present invention is not limited to having such a brush hair structure with a double spiral arrangement. It may be configured by clamping only a few filaments, which are not even helical, at positions shifted to the same one side to form a region composed of long brush hairs and short brush hairs. Also, as shown in FIG. 4, only a partial region of the brush part 2, in this example, the central region R1 in the axial direction, has a structure with a long and short double spiral arrangement composed of the arrangement 5A of the long brush hairs 5a and the arrangement 5B of the short brush hairs 5b, and the other regions may of course have a single spiral arrangement structure in which the central positions of the filaments are clamped by the wire as in the prior art.

[0027] Also, in the example of FIGS. 3(a) and 3(b), as the brush hair structure with a double spiral arrangement, the positions of the filaments 3 clamped by the wire 4 are all shifted by the same distance to one side, and the lengths of the brush hairs 5a and 5b are each set to be constant. However, the present invention is not limited to this. For example, as shown in FIG. 5, the positions shifted to the one side are different from each other (the ratio of the length of the long brush hair formed from the filament 3 to the length of the short brush hair ((length of long brush hair) / (length of short brush hair)) is different), and a plurality of regions with a double spiral arrangement structure (regions with a double spiral arrangement composed of the arrangements 5A and 5B, regions with a double spiral arrangement composed of the arrangements 5A' and 5B', and regions with a double spiral arrangement composed of the arrangements 5A'' and 5B'') may be provided.

[0028] Moreover, instead of combining regions of a plurality of double-helix arrays step by step as shown in FIG. 5, as shown in FIG. 6, the shifted position on one side continuously changes (the above ratio also continuously changes), and the lengths of the long brush hairs 5a and the short brush hairs 5b also continuously change, which can also be a double-helix array.

[0029] Furthermore, by changing the length of the filament, other forms can be considered. That is, in FIGS. 5 and 6, the displacement amount of the clamping position of the filaments 3 of the same length was changed. For example, in the example of FIG. 5, by changing the length of the filaments 3 constituting each double-helix array, as shown in FIG. 7, a preferred example is one in which the lengths of the short brush hairs 5b, 5', 5'' constituting each array 5B, 5B', 5B'' are set to be the same.

[0030] With the same idea, as shown in FIG. 8, the length of the filament 3 can be continuously changed, the shifted position on one side continuously changes (the above ratio also continuously changes), and the length of the short brush hair 5b can be set to be constant. Also, in FIGS. 7 and 8, the length of the short brush hair 5b was made constant, but as shown in FIG. 9, the length of the filament 3 can be continuously changed, and the length of the short brush hair 5b can also be continuously changed in the same way as the long brush hair 5a.

[0031] The various modification examples shown in FIGS. 4 to 9 are only examples, and of course, combinations of these and other forms can also be set. Thus, the present invention can take various forms, and for users of various age groups with different sizes of interdental spaces, it can be set to have an optimal passing diameter regardless of the length of the brush hairs, and it is an interdental cleaning tool with a novel structure having a high degree of freedom in design.

[0032] Regardless of the various forms, the length of the short brush hair is preferably 1.0 mm or more, and more preferably set to be 4 mm or less. If it is shorter than 1.0 mm, it may not be able to sufficiently support the adjacent relatively long brush hairs, and it may be difficult to arrange the filaments between the wires during manufacturing.

[0033] The ratio of the length of the long brush hairs formed from the same filament 3 to the length of the short brush hairs ((length of long brush hairs) / (length of short brush hairs)) is preferably 12 or less. When it exceeds 12, the long brush hairs become relatively heavy, making it difficult to twist the wire during manufacturing. Moreover, the long brush hairs become too long, and the passage diameter becomes considerably large. More preferably, it is set to 1.1 or more.

[0034] Similar to the conventional case, after forming the brush part 2 by twisting the wire 4 (twist process), the outer peripheral part can be cut (cut process) to adjust it to a desired outer shape. Its shape can be processed into various shapes such as a cylinder type, taper type, barrel type (barrel shape), drum type, or a shape combining two or more of these shapes, similar to the conventional case. For example, as shown in FIGS. 3(a) and 3(b), by sandwiching a plurality of filaments 3 arranged continuously in the axial direction of the wire 4 so that they are displaced to the same side and twisting (twisting), a helical arrangement 5A of long brush hairs 5a formed by the plurality of filaments 3 and a helical arrangement 5B of short brush hairs 5b also formed by the plurality of filaments 3 are obtained, and a brush part 2 having a cylinder-type double-helix arrangement brush hair structure can be produced. Also, as shown in FIG. 11, by cutting the brush part 2 having a cylinder-type double-helix arrangement brush hair structure produced as described above with a hair clipper, a taper-type brush part 2' can be produced. Also, as shown in FIG. 12, by cutting the brush part 2 having a cylinder-type double-helix arrangement brush hair structure produced as described above with a hair clipper, a barrel-type brush part 2'' can be produced. However, when cutting, since the shaft part made of the folded wire 4 is rotated and machined with a tool, only the short brush hairs 5b cannot be cut, and the long brush hairs 5a will be mainly cut. Therefore, in order not to disrupt the arrangement of the long and short brush hairs, for example, after forming the brush part 2 in a shape close to the target outer contour shape in the form shown in FIGS. 5 to 9 above, it is also preferable to further cut it.

[0035] It is preferable to apply glycerin to the surface of the filament 3 clamped by the wire 4. By applying glycerin, it is possible to prevent the filament from further shifting from the clamping position even when centrifugal force is applied when the wire 4 is twisted, and an interdental brush as designed can be efficiently manufactured.

Example

[0036] Hereinafter, the samples of the examples and comparative examples were prepared, and the results of the passing test and the cleaning test will be described.

[0037] (Sample) In the sample of Example 1, when arranging a plurality of filaments, which were cut to a certain length and had glycerin applied thereto, between the wires (made of stainless steel, diameter 0.25 mm) folded in half, they were clamped between the wires at a position shifted to one side from the central position in the length direction of the filaments. Then, by twisting the wires, as described with reference to FIGS. 1 to 3, around the twisted wire 4, a brush part 2 having a brush hair structure of a long and short double helix arrangement composed of a spiral arrangement of long brush hairs 5a formed by a plurality of filaments 3 and a spiral arrangement of short brush hairs 5b also formed by a plurality of filaments 3 was produced. Next, as shown in "Example 1" of FIG. 13, the ends of the brush hairs 2 were trimmed so that the outer shape of the brush part 2 became a cylinder shape, and it was fixed to a rod-shaped handle body to obtain a sample of an interdental brush. The length A of the long brush hairs was 2.9 mm, and the length B of the short brush hairs was 2.5 mm.

[0038] The sample of Example 2 was the same as that of Example 1 except that the length of the filaments was changed and the position (shift amount) clamped by the wires was changed, and a cylinder-shaped brush part was manufactured in the same manner as in Example 1. The length A of the long brush hairs was 5 mm, and the length B of the short brush hairs was 3 mm.

[0039] The sample of Example 3 was prepared in the same manner as Example 1, except that the length of the filament was changed and the position (displacement amount) where it was clamped with the wire was changed, to produce a brush part having a brush hair structure with a double helix arrangement of long and short brush hairs. Then, as shown in "Example 3" of Fig. 13, the ends of the brush hairs were trimmed so that the outer shape of the brush part became tapered. The length A of the longest brush hair is 3.55 mm, and the length B of the short brush hairs except for the trimmed tip brush hairs is 2.5 mm.

[0040] The sample of Example 4 was prepared in the same manner as Example 1, except that the length of the filament was changed and the position where it was clamped with the wire was changed, to produce a brush part having a brush hair structure with a double helix arrangement of long and short brush hairs. According to the manufacturing method shown in Fig. 12, as shown in "Example 4" of Fig. 13, the ends of the brush hairs were trimmed so that the outer shape of the brush part 2 became barrel-shaped. The length A of the longest brush hair is 2.85 mm, and the length B of the short brush hairs except for the trimmed tip brush hairs is 2.5 mm.

[0041] The sample of Example 5 was prepared in the same manner as Example 1, except that the length of the filament was changed and the position where it was clamped with the wire was changed, to produce a brush part having a brush hair structure with a double helix arrangement of long and short brush hairs. According to the manufacturing method shown in Fig. 11, as shown in "Example 5" of Fig. 13, the ends of the brush hairs were trimmed so that the outer shape of the brush part became tapered. The length A of the longest brush hair is 5.2 mm, and the length B of the short brush hairs except for the trimmed tip brush hairs is 1 mm.

[0042] The sample of Example 6 was prepared in the same manner as Example 1, except that the length of the filament was changed and the position where it was clamped with the wire was changed, to produce a brush part having a brush hair structure with a double helix arrangement of long and short brush hairs. According to the manufacturing method shown in Fig. 11, as shown in "Example 6" of Fig. 13, the ends of the brush hairs were trimmed so that the outer shape of the brush part became tapered. The length A of the long brush hairs is 5.2 mm, and the length B of the short brush hairs except for the trimmed tip brush hairs is 2 mm.

[0043] The sample of Example 7 was prepared in the same manner as Example 1, except that the length of the filaments was changed and the clamping position by the wire was changed, to produce a brush part having a brush hair structure of a double helix array of long and short lengths. As shown in "Example 7" of Fig. 13, the ends of the brush hairs were trimmed so that the outer shape of the brush part 2 became a cylinder shape. The length A of the long brush hairs was 12 mm, and the length B of the short brush hairs was 1 mm.

[0044] The sample of Comparative Example 1 was the same as Example 1, except that it was a conventional type with the clamping position by the wire at the central part of the filament. A conventional type brush part with brush hairs of the same length symmetrically arranged around the wire was produced. As shown in "Comparative Example 1" of Fig. 14, the ends of the brush hairs were trimmed so that the outer shape of the brush part became a cylinder shape. The length A of the brush hairs was 2.6 mm.

[0045] The sample of Comparative Example 2 was the same as Example 2, except that it was a conventional type with the clamping position by the wire at the central part of the filament. A conventional type brush part with brush hairs of the same length symmetrically arranged around the wire was produced. As shown in "Comparative Example 2" of Fig. 14, the ends of the brush hairs were trimmed so that the outer shape of the brush part became a cylinder shape. The length A of the brush hairs was 5 mm.

[0046] The sample of Comparative Example 3 was the same as Example 3, except that it was a conventional type with the clamping position by the wire at the central part of the filament. A conventional type brush part with brush hairs of the same length symmetrically arranged around the wire was produced. According to the manufacturing method shown in Fig. 11, as shown in "Comparative Example 3" of Fig. 14, the ends of the brush hairs were trimmed so that the outer shape of the brush part became a tapered shape. The length A of the longest brush hairs was 3.55 mm.

[0047] The sample of Comparative Example 4 is the same as that of Example 4 except that the clamping position by the wire is at the center of the filament. A conventional brush part with brush hairs of the same length symmetrically arranged around the wire was produced. According to the manufacturing method of FIG. 12, as shown in "Comparative Example 4" of FIG. 14, the ends of the brush hairs were trimmed so that the outer shape of the brush part became a barrel shape. The length A of the longest brush hair is 2.85 mm.

[0048] The sample of Comparative Example 5 is the same as that of Example 5 except that the clamping position by the wire is at the center of the filament. A conventional brush part with brush hairs of the same length symmetrically arranged around the wire was produced. According to the manufacturing method of FIG. 11, as shown in "Comparative Example 5" of FIG. 14, the ends of the brush hairs were trimmed so that the outer shape of the brush part became a tapered shape. The length A of the longest brush hair is 5.2 mm.

[0049] (Passability test) The brush parts of the samples of the above Examples 1 to 7 and Comparative Examples 1 to 5 were inserted into holes having a predetermined diameter simulating the gap between teeth, and the minimum passing diameter allowing smooth movement was measured by inserting and removing them. The obtained results are shown in Table 1.

[0050]

Table 1

[0051] As can be seen from Table 1, in Example 1, although the length of the long brush hair is 11% longer than that of Comparative Example 1, the minimum passing diameter is the same at 1.5 mm. It can be understood that the interdental brush of the present invention can reduce the passing diameter compared to the conventional interdental brush while having long brush hairs. Also, in Example 2 and Comparative Example 2, Example 3 and Comparative Example 3, Example 4 and Comparative Example 4, Example 5 and 6 and Comparative Example 5, the lengths of the long brush hairs are almost the same, but the minimum passing diameters of the samples of Examples 2 to 6 are smaller than those of the corresponding Comparative Examples 2 to 5 respectively. From this point as well, it can be understood that the interdental brush of the present invention can reduce the passing diameter compared to the conventional interdental brush while having long brush hairs.

[0052] Also, the interdental brush of Example 7 has a relatively long length of the long brush bristles of 12 mm, but has the same minimum passing diameter as Comparative Example 2. It can be seen that even as an interdental brush with long brush bristles as in Example 7, the passing diameter can be suppressed.

[0053] (Cleaning test)

[0054] Adjacent tooth row numbers 6 and 7 of a commercially available jaw interdental model (interdental size: diameter 1.5 mm (equivalent to ISO Size 4)) were selected, and artificial plaque was applied to the surfaces of the respective teeth to create interdental dirt. The brush parts of the samples of Example 1 and Comparative Example 1 were inserted between these two tooth row numbers 6 and 7, and the insertion and removal were performed to carry out the cleaning operation. Regarding the evaluation of the cleaning performance, the teeth of tooth row numbers 6 and 7 after cleaning were taken out from the jaw interdental model, and their surfaces were observed with a digital microscope, and the area where the dirt had fallen off was measured. Then, the ratio of the area of Example 1 to that of Comparative Example 1 was calculated as the cleaning performance improvement rate.

[0055] Next, the interdental size of the above tooth row numbers 6 and 7 was changed to a diameter of 1.8 mm (equivalent to ISO Size 5)), the brush parts of the samples of Example 1 and Comparative Example 1 were inserted between the interdentals, and the cleaning operation was performed in the same manner. Then, in the same manner as above, the area where the dirt had fallen off after cleaning was measured for each, and the ratio of the area of Example 1 to that of Comparative Example 1 was calculated as the cleaning performance improvement rate. The results are shown in Table 2.

[0056]

Table 2

[0057] As can be seen from Table 2, for the interdental size equivalent to ISO Size 4, the sample of Example 1 had about 150% improvement in cleaning performance on average for the teeth of tooth row numbers 6 and 7 compared to the sample of Comparative Example 1, and for the interdental size equivalent to ISO Size 5, it had about 230% improvement on average. Therefore, it can be understood that the interdental brush of the present invention has a brush hair structure of a long and short double helix arrangement consisting of a helical arrangement of long brush hairs and a helical arrangement of short brush hairs, thereby improving the cleaning performance and having high cleaning performance and a feeling of cleaning.

Explanation of Symbols

[0058] 1 Interdental brush 2,2’ Brush part 3 Filament 4 Wire 5a Short brush hair 5b Long brush hair 5A Arrangement 5B Arrangement 6 Handle part

Claims

1. An interdental brush having a brush part in which a plurality of filaments are sandwiched between folded and twisted wires, and a plurality of brush hairs made of the filaments protrude radially around the wires, wherein at least some of the plurality of filaments are sandwiched between the wires at a position shifted to one side from the central position in the longitudinal direction of the filament, whereby short brush hairs are formed on the one side and long brush hairs are formed on the other side. An interdental brush characterized by this.

2. A plurality of filaments arranged continuously in the wire axis direction are sandwiched at the same shifted position on the one side, thereby having a brush hair structure of a long and short double helix arrangement consisting of a helical arrangement of long brush hairs formed by the plurality of filaments and a helical arrangement of short brush hairs also formed by the plurality of filaments, The interdental brush according to claim 1.

3. The length of the short brush hairs is 1.0 mm or more, The interdental brush according to claim 1.

4. The ratio of the length of the long brush hairs to the length of the short brush hairs ((length of long brush hairs) / (length of short brush hairs)) formed from the same filament is 12 or less, The interdental brush according to claim 1.

5. At least some of the filaments are filaments having a tapered portion tapering towards one end or both ends, and the long brush hairs or the short brush hairs formed from the filaments are tapered, The interdental brush according to claim 1.

6. When arranging a plurality of filaments cut to a predetermined length between the wires folded in half, at least some of the plurality of filaments are sandwiched between the wires at a position shifted to one side from the central position in the longitudinal direction of the filament, and then the wire is twisted, so that short brush hairs are formed on one side and long brush hairs are formed on the other side around the twisted wire. A method for manufacturing an interdental brush that forms a brush part in which a plurality of brush hairs protrude radially.

7. A plurality of filaments arranged continuously in the wire axis direction are sandwiched at the same shifted position on the one side, The method for manufacturing an interdental brush according to claim 6, which forms a brush hair structure having a long and short double helical arrangement consisting of a helical arrangement of long brush hairs formed by the plurality of filaments and a helical arrangement of short brush hairs also formed by the plurality of filaments.

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