JP2024117546A - Interdental brushes - Google Patents

Abstract

[Problem] To provide an interdental brush that is highly stable when inserted and has excellent durability even when the neck is tilted relative to the row of teeth during use. [Solution] When the handle is fixed and a force of a predetermined magnitude is applied to the tip of the neck in a direction perpendicular to the axis of the handle, the direction in which the amount of bending of the neck is greatest is direction A, and the direction in which the amount of bending is least is direction B, the ratio (Da/Db) of the amount of bending of the neck in direction A when a force is applied in direction A to the amount of bending of the neck in direction B when a force is applied in direction B is 1.5 to 2.2. [Selected Figure] Figure 1

Description

Application for exception to loss of novelty has been filed

The present invention relates to an interdental brush that includes a handle portion, a neck portion that extends from the tip of the handle portion along the axial direction of the handle portion, and a brush portion in which multiple cleaning bodies are radially protruded around a core portion that extends from the tip of the neck portion along the axial direction of the neck portion.

Conventionally, this type of interdental brush has been proposed in which the shape of the neck is a combination of a straight section and a concave tapered section to improve durability (Patent Document 1). In addition, an interdental brush has been proposed in which the wire is less likely to come loose and durability is improved by using a soft resin for the neck and a hard resin for the handle (Patent Document 2). However, these interdental brushes have a problem in that the cross section of the neck is a perfect circle and there is no directionality in the direction of bending, which makes the brush part prone to wobbling when inserted between the teeth, reducing maneuverability in the mouth and ease of insertion into the interdental space.

To solve this problem, an interdental brush has been proposed that provides directionality in the direction of bending by providing a flat horizontally elongated cross-sectional structure in the neck portion, and allows the neck portion to be repeatedly bent by hand in the direction that is most likely to bend, thereby enabling the brush portion to be inserted straight in the axial direction between the teeth in the molar region (Patent Documents 3 and 4). Because the neck portion of these interdental brushes is bent by hand, the dimensions are set on the assumption that the interdental brush will be parallel to the dentition.

However, in actual use, there are many cases where the neck is used as is without being bent by hand, and is often inserted with the neck tilted relative to the dentition. When attempting to insert the brush part between the teeth with the neck tilted relative to the dentition in this way, the neck does not follow (flex and deform) in response to the deformation of the brush part (core), resulting in poor insertion ability between the teeth, particularly in the molar area, and also causing stress to concentrate at the base of the core, making it more likely to break.

WO2012/011574 JP 2017-144104 A JP 2016-155022 A JP 2018-068512 A

In view of the above situation, the present invention aims to solve the problem of providing an interdental brush that is highly stable when inserted and has excellent durability, even if the neck portion is tilted relative to the dentition during use.

The present invention includes the following inventions.
(1) An interdental brush comprising a handle portion having gripping surfaces on at least the front and rear surfaces of its outer circumferential surface, a neck portion extending from the tip of the handle portion along the axial direction of the handle portion, and a brush portion having a plurality of cleaning bodies protruding radially around a core portion extending from the tip of the neck portion along the axial direction of the neck portion, wherein, when the handle portion is fixed and a force of a predetermined magnitude is applied to the tip position of the neck portion in a direction perpendicular to the axis, the direction in which the amount of bending of the neck portion is greatest is direction A and the direction in which the amount of bending is least is direction B, the ratio (Da/Db) of the amount of bending of the neck portion in direction A when a force is applied in direction A to the amount of bending of the neck portion in direction B when a force is applied in direction B is 1.5 to 2.2.

(2) An interdental brush as described in (1), in which the amount of deflection (Da) of the neck portion in the A direction when a force of 100 gf is applied in the A direction is 1.5 mm or more, and the amount of deflection (Db) of the neck portion in the B direction when a force of 100 gf is applied in the B direction is 0.7 mm or more.

(3) An interdental brush according to (1) or (2), in which the A direction and the B direction are mutually perpendicular directions, and the direction in which the component (da) of the amount of deflection of the neck portion in the A direction and the component (db) of the B direction are equal when a force of a predetermined magnitude is applied to the tip position of the neck portion in a direction perpendicular to the axis is a direction rotated 25 to 35 degrees from the B direction toward the A direction as viewed from the axial direction.

(4) An interdental brush according to any one of (1) to (3), in which the neck portion has a horizontally elongated cross-sectional structure that is flat when viewed in cross section, the A direction is the front-to-back direction, and the B direction is the left-to-right lateral direction perpendicular to the A direction.

According to the interdental brush of the present invention, when the brush portion is inserted parallel to the dentition during use, it is prone to bending in the direction A, so it can be deformed along the dentition and smoothly inserted, and is less prone to deformation in the direction B than in the direction A, which improves operational stability when inserted between the teeth. Furthermore, by setting the ratio (Da/Db) of the bending amount (Da) to the bending amount (Db) to be 1.5 to 2.2, it is highly insertable between the teeth of the molars and has excellent durability, even when the neck portion is tilted relative to the dentition during use.

1 is a perspective view showing an interdental brush according to a representative embodiment of the present invention. FIG. FIG. FIG. 11 is an explanatory diagram of the main parts showing how the neck portion bends when the handle portion of the interdental brush is fixed and a force is applied in the direction A to the tip portion of the neck portion. FIG. 11 is an explanatory diagram of the main parts showing how the neck portion bends when the handle portion of the interdental brush is fixed and a force is applied in the direction B to the tip portion of the neck portion. An explanatory diagram of the main parts viewed from the axial direction, showing how the neck portion bends when a force is applied in a direction perpendicular to the axis and rotated 25 to 35 degrees from direction B toward direction A. Graph showing the results of a deflection test of the sample of Example 1. Graph showing the results of a deflection test of the sample of Example 2. Graph showing the results of a deflection test of the sample of Example 3. Graph showing the results of a deflection test of the sample of Comparative Example 1. Graph showing the results of a deflection test of the sample of Comparative Example 2. Graph showing the results of a deflection test of the sample of Comparative Example 3.

Next, an embodiment of the present invention will be described in detail with reference to the attached drawings.

As shown in Figs. 1 to 3, an interdental brush 1 according to a representative embodiment of the present invention comprises a handle portion 2, a neck portion 3 that extends from the tip of the handle portion 2 along the axial direction of the handle portion 2 and gradually tapers toward the tip, and a brush portion 4 consisting of a core portion 40 that extends from the tip of the neck portion 3 along the axial direction of the neck portion and has multiple cleaning bodies 41 protruding radially around it. The handle portion 2 and the neck portion 3 form a handle body 10 that is held by the user.

The interdental brush 1 according to the present invention is particularly characterized in that, when the handle portion 2 is fixed and a force of a predetermined magnitude is applied to the tip 3a of the neck portion 3 in a direction perpendicular to the axis of the neck portion 3, the ratio (Da/Db) of the amount of bending of the neck portion in the A direction when a force is applied in the A direction to the amount of bending of the neck portion in the B direction when a force is applied in the B direction is 1.5 to 2.2, where the direction in which the amount of bending of the neck portion 3 is greatest is direction A and the direction in which the amount of bending is least is direction B. Taking into account the amount of force actually applied by the user, it is preferable that the applied force be a predetermined force of 100 gf or more, more preferably within the range of 100 to 300 gf.

By having such flexibility, the interdental brush of the present invention has a directional tendency to bend easily in direction A, and when the brush portion is inserted parallel to the dentition during use, it bends easily in direction A, so it deforms along the dentition and can be inserted smoothly, and is less likely to deform in direction B, providing high operational stability when inserted between the teeth. In addition, by setting Da/Db to 1.5 to 2.2, even if the neck portion is tilted relative to the dentition during use, it is highly insertable between the teeth of the molars and has excellent durability.

The brush section 4 is, for example, a core section 40 made of fine metal wire, with multiple cleaning bristles 41 (filaments) radially planted along its length and then trimmed to a desired shape. More specifically, a fine metal wire (wire) is folded in half, multiple filaments are placed between the folded wire, and the fine metal wire is twisted to plant multiple cleaning filaments (bristles 41) radially around the core section 40 made of fine metal wire. The filaments are then trimmed to form a desired outer peripheral shape (in this example, a truncated cone shape).

The base end of the core 40 is provided with a bent anchor portion (not shown), and this anchor portion is embedded in the handle body 10 (the neck portion 3 and the tip portion of the handle portion 2), so that the brush portion 4 will not fall off the handle body 10 during use, even if the brush portion 4 is rotated while inserted between the teeth, for example.

The fine metal wire constituting the core 40 may be made of a metal such as stainless steel or a Co alloy. The diameter of the wire may be set to about 0.20 to 0.45 mm. The filament may be made of a thermoplastic synthetic resin such as polyamide resins such as nylon and aramid (polyamide 610, polyamide 612, polyamide 6, polyamide 66), polyester resins such as polybutylene terephthalate, polypropylene terephthalate, polytrimethylene terephthalate, and polyethylene terephthalate, or polyolefin resins such as polypropylene and polyethylene. There are no particular limitations on the thickness or cross-sectional shape of the filament, and various shapes may be used.

The brush part of the present invention is not limited to being made of such a fine metal wire core 40 and filament bristles 41, but can be made of a variety of materials, such as a core and brush part integrally molded from a synthetic resin material, or a core molded mainly from a synthetic resin material, with multiple cleaning protrusions around it as cleaning bodies molded in two colors from a material such as thermoplastic elastomer, thermosetting silicone rubber, or synthetic rubber.

As shown in Figures 1 to 5, the handle body 10 comprises a rod-shaped handle portion 2 that serves as the main grip, and a bendable neck portion 3 that extends from the tip of the handle portion 2 and tapers toward the brush portion 4; these are integrally molded from synthetic resin. The base side of the core portion 40 is supported by being embedded by insert molding into the neck portion 3 and the tip of the handle portion 2 so that it cannot fall off.

The synthetic resin material of the handle body 10 may be a thermoplastic synthetic resin material such as polypropylene, polyethylene, polyethylene terephthalate, polycyclohexylene dimethylene terephthalate, saturated polyester resin, polymethylmethacrylate, cellulose propionate, polyurethane, polyamide, polycarbonate, or ABS (acrylonitrile butadiene styrene). Polyethylene is particularly suitable because of its excellent durability when repeatedly bent.

The handle portion 2 is configured so that the user can grip it firmly with the fingers. It has a flattened, roughly hexagonal shape in cross section, and as shown in FIG. 2, the middle portion 22 is narrower than the upper portion 21 on the tip side and the lower portion 23 on the base side in front view. The middle portion 22 is provided with a plurality of grooves 22c spaced apart in the axial direction around the entire circumference, and each groove 22c is configured to allow the handle portion 2 to bend easily. In addition, the front and rear surfaces of the upper and middle portions 22 are provided with a plurality of anti-slip grooves 24 extending in the axial direction in parallel. However, the handle portion of the present invention is not limited to this configuration, and various structures are possible.

The neck portion 3 is configured to taper gradually toward the tip so as to be less likely to come into contact with tissues in the mouth, and is configured to have directionality so as to bend easily in a predetermined direction (when the handle portion is fixed and a load is applied to the tip of the neck portion in a direction perpendicular to the axis, the amount of bending of the neck portion differs depending on the direction). In this example, the neck portion 3 has a horizontally elongated, flat cross-sectional shape with a larger left-right width than a front-to-back thickness so that it can bend easily in the front-to-back direction.

In other words, the front-to-back direction is set as the "A direction" of the present invention, and the side, i.e., the left-right lateral direction, is set as the "B direction" of the present invention. Note that the "A direction" and "B direction" of the present invention are not limited to the front-to-back direction and the left-right lateral direction as in this example, respectively, and one or both may be diagonal directions, or the A direction may be the left-right lateral direction and the B direction may be the front-to-back direction. Also, although the mutual angles of the "A direction" and the "B direction" are perpendicular to each other in this example, they are not limited to this.

The front and rear surfaces of the neck portion 3 are provided with multiple widthwise extending grooves 3c arranged in parallel at intervals in the axial direction, and these grooves 3c facilitate bending of the neck portion 3 in the front-rear direction (direction A) and function as a non-slip surface when operated with fingers. In addition, the neck portion 3 of this example has a base end side region R1 along the axial direction in which the rate of change in left-right width and front-rear thickness gradually decreases from the base end side to the tip end side in both front and side views, and the ridgelines L1, L2 are tapered with concave curves (first tapered shape portion 31).

Continuing from the tip of region R1 is region R2 (second tapered portion 32) with linear ridgelines L3 and L4, where the rate of change in left-right width and front-back thickness decreases toward the tip is constant. Continuing from the tip of region R2 is region R3 (semispherical portion 33), which is a substantially hemispherical portion that becomes the tip of neck portion 3.

The length dimension along the axial direction of the first tapered portion 31 (region R1) is preferably set to be greater than the length dimension along the axial direction of the second tapered portion 32 (region R2). The length dimension along the axial direction of the second tapered portion 32 (region R2) is preferably set to 7.0 mm or less, and the left and right width of the second tapered portion 32 (region R2) is preferably a tapered shape that changes within a range of 1.8 to 2.8 mm, and the front and rear thickness of the second tapered portion 32 (region R2) is preferably a tapered shape that changes within a range of 1.6 to 2.6 mm.

In this example, the combination of the first tapered portion 31 and the second tapered portion 32, particularly in the shape described above, sets the amount of deflection (Db) in the B direction to 0.7 mm or more, and the value of Da/Db to 1.5 to 2.2. However, the present invention is not limited to this structure of the neck portion 3, and it goes without saying that other structures are also acceptable as long as the value of Da/Db can be set to 1.5 to 2.2.

The amount of deflection is preferably set so that when a force of 100 gf is applied in the A direction, the amount of deflection in the A direction (Da) is 1.5 mm or more, and when a force of 100 gf is applied in the B direction, the amount of deflection in the B direction (Db) is 0.7 mm or more. Da is more preferably set to 1.6 mm or more, and Db is more preferably set to 0.8 mm or more.

As shown in Figure 6, it is preferable for the neck portion 3 to be in a direction perpendicular to the axis at the tip position of the neck portion 3, and for the direction F in which the component (da) in the A direction and the component (db) in the B direction of the amount of deflection when a force F of a predetermined magnitude is applied are equal (da = db), and the direction F is rotated 25 to 35 degrees from the direction B toward the direction A as viewed from the axial direction. With such an interdental brush, when the neck portion 3 is inclined relative to the dentition during use, it becomes easier to insert the neck portion 3 between the teeth of the molars.

Although the embodiments of the present invention have been described above, the present invention is not limited to these examples, and can of course be embodied in various forms without departing from the spirit of the present invention.

Below, we will explain the results of creating interdental brush samples and testing the effect of deflection on insertion ability.

(sample)
Several interdental brush samples were prepared (a total of six samples: Examples 1 to 3 and Comparative Examples 1 to 3, each with different brush part dimensions). The configurations were the same except for the brush part, with the handle body, including the neck, being made of low-density polyethylene (LLDPE), and the core of the brush part being made by bending a thin metal wire (stainless steel, φ0.25 mm) and twisting it with a filament (nylon, triangular cross section) placed between them.

The shape of the brush part of each sample basically has the shape shown in Figures 1 to 3, and the left-right width and front-to-back thickness at the tip of the second tapered portion 32 (region R2) are set for each sample as shown in Table 1 below, and the shapes and dimensions of the first tapered portion 31 (region R1) and hemispherical portion 33 (region R3) were also fine-tuned accordingly. The front-to-back direction of the brush part of each sample is the "A direction" of the present invention, and the left-to-right lateral direction is the "B direction" of the present invention.

(Calculation of Deflection Amount)
Each sample was placed in a horizontal position with the handle fixed to a table, a 100g weight (F = 100gf) was hung from the tip of the neck (the base of the wire), and the amount of vertical downward displacement of the tip of the neck was measured as the amount of deflection. The sample was rotated around the axis in 15° increments, with the left-right width direction (direction B) of the neck at an angle of 0° and the front-back direction (direction A) at an angle of 90°, and fixed in different orientations for measurement, and the component of the A direction (da) and the component of the B direction (db) of each measured amount of displacement were calculated.

(Test of insertability between teeth)
A total of six levels of analysis were performed for the Examples and Comparative Examples, and a comparison was made based on the results of a questionnaire survey conducted when the product was actually used to evaluate the ease of insertion between the molar teeth. Excellent ease of insertion was marked with a "◎", good ease with a "◯", poor ease with a "△", and poor ease with a "×".

(Test Results)
The test results for each sample are shown in Table 2 below and in FIGS.

All of the samples in Examples 1 to 3 had good interdental insertion properties, with Examples 1 and 2 being particularly good. The samples in Comparative Examples 1 and 3 had a large difference (large Da/Db ratio) between Da (the amount of deflection in A direction when force is applied in A direction (front-back direction)) and Db (the amount of deflection in B direction when force is applied in B direction (left-right side)), and it is believed that when the handle is tilted relative to the dentition, the neck portion does not follow the deformation of the wire, resulting in poor or deteriorated interdental insertion properties.

The sample of Comparative Example 2 has a cylindrical neck cross-sectional shape, so the Da/Db ratio is close to 1.0. For this reason, it is presumed that because the Da/Db value is small, the neck does not bend sufficiently when inserted between the teeth in the molar area, and when the wire hits the interdental area, the angle with respect to the interdental opening becomes large, resulting in poor insertion properties.

These results show that the insertion into the interdental space is improved if the Da/Db ratio is in the range of 1.5 to 2.2. The deflection in the A direction is 1.5 mm or more, and the deflection in the B direction is 0.7 mm or more.

The above results also show that the direction in which force is applied so that the bending components da and db have the same value is also important; if this direction is closer to direction B (the rotation angle from direction B becomes smaller), the handle will be difficult to follow when tilted, reducing interdental insertion ability and durability; and if this direction is around 45 degrees, the direction of bending of the neck will lose directionality, making the brush part more likely to shake when inserted between the teeth, reducing operability in the oral cavity and interdental insertion ability. To improve insertion ability into the interdental space, setting the rotation angle to around 24 to 30 degrees will result in high interdental insertion ability and durability.

REFERENCE SIGNS LIST 1 interdental brush 2 handle portion 3 neck portion 3a tip portion 3c groove 4 brush portion 10 handle body 21 upper portion 22 middle portion 22c groove 23 lower portion 24 groove 31 first tapered portion 33 hemispherical portion 40 core portion 41 bristles

Claims (4)

The brush includes a handle portion, a neck portion extending from a tip of the handle portion along an axial direction of the handle portion and configured to be thinner than the handle portion, and a brush portion having a core portion extending from the tip of the neck portion along the axial direction of the neck portion and including a plurality of cleaning bodies radially protruding from the core portion,
An interdental brush characterized in that, when the handle portion is fixed and a force of a predetermined magnitude is applied to the tip position of the neck portion in a direction perpendicular to the axis of the handle portion, the direction in which the amount of bending of the neck portion is greatest is direction A and the direction in which the amount of bending is least is direction B, the ratio (Da/Db) of the amount of bending of the neck portion in direction A when a force is applied in direction A to the amount of bending of the neck portion in direction B when a force is applied in direction B is 1.5 to 2.2. The interdental brush according to claim 1, wherein the amount of deflection (Da) of the neck portion in the A direction when a force of 100 gf is applied in the A direction is 1.5 mm or more, and the amount of deflection (Db) of the neck portion in the B direction when a force of 100 gf is applied in the B direction is 0.7 mm or more. The interdental brush according to claim 1 or 2, wherein the A direction and the B direction are mutually perpendicular directions, and the direction in which the component (da) in the A direction of the amount of deflection of the neck portion is equal to the component (db) in the B direction when a force of a predetermined magnitude is applied to the tip position of the neck portion in a direction perpendicular to the axis is a direction rotated 25 to 35 degrees from the B direction toward the A direction as viewed from the axial direction. 2. The interdental brush according to claim 1, wherein the neck portion has a horizontally elongated cross-sectional structure that is flat when viewed in cross section, the A direction being a front-back direction, and the B direction being a left-right lateral direction perpendicular to the A direction.

Images