JP7796469B2 - toothbrush - Google Patents

Description

The present invention relates to a toothbrush.

When you have periodontal disease, pain occurs when the toothbrush comes into contact with your gums. If bristles with low stiffness are used to improve the feeling of contact with the gums, the basic function of cleaning the oral cavity, is reduced. For example, Patent Document 1 discloses a toothbrush in which bristle bundles with branched bristles, where only the tips of the bristles are branched, are provided on both outer sides of the head in the width direction. Furthermore, Patent Document 2 discloses a toothbrush in which at least one of the outer bristle bundles and the inner bristle bundles has two half-bundle sections with different bristle lengths.

In the toothbrush disclosed in Patent Document 1, the branched bristles at the ends bend and act as cushioning, improving the feel against the gums. Furthermore, because the branched bristles are only located at the tips of the bristles, a decrease in bristles stiffness is suppressed, ensuring oral cavity cleaning power. In the toothbrush disclosed in Patent Document 2, the bristles that make up the brush have three different height levels, allowing the bristles to come into contact with a wide range of areas to be cleaned in the oral cavity, while also ensuring high cleaning performance for each area.

Japanese Patent Application Laid-Open No. 2016-209097 Japanese Patent Application Laid-Open No. 2016-209016

However, in the toothbrush of Patent Document 1, when bristle bundles with branched bristles at the ends are folded symmetrically and implanted, the branched bristles all have the same bristles length, which restricts the range of movement of the bristles and reduces their function as a cushioning material. Patent Document 2 also discloses that branched bristles may be used except for the half-hair bundles of the outer bristles, which have the longest bristles. However, with this configuration, because the half-hair bundles of the outer bristles that are most likely to come into contact with the gums do not have branched bristles at the ends, they are difficult to feel as a cushioning material and do not contribute to improving the comfort of the bristles against the gums.

The present invention was made in consideration of the above points, and aims to provide a toothbrush that is gentle on the gums and contributes to improved cleaning power.

In accordance with a first aspect of the present invention, there is provided a toothbrush having a head portion with multiple bristle bundles planted on the bristle implantation surface, and a handle body extending from the head portion, wherein the bristle bundles have outer bristle bundles arranged at the outermost periphery and inner bristle bundles arranged inside the outer bristle bundles, and the outer bristle bundles are formed by bifurcating bristles whose tips are branched on both sides of the length, and have two half bristle bundle portions with different bristle lengths.

Furthermore, in the toothbrush according to one aspect of the present invention described above, the bristles are tapered bristles that taper toward the tip.

Furthermore, in the toothbrush according to one aspect of the present invention, the inner bristle bundle has a plurality of second bristles, and the second bristles are tapered bristles that taper toward the tip.

Furthermore, in the toothbrush according to one aspect of the present invention described above, the bristles of the inner bristles are longer than the bristles of the outer bristles.

Furthermore, in the toothbrush according to one aspect of the present invention, of the two half hair bundles, the outer half hair bundle is shorter than the inner half hair bundle.

Furthermore, in the toothbrush according to one aspect of the present invention, the difference in bristle length between the two half tufts is 0.5 mm or more and 2.0 mm or less, and when the branched length of the end-branched bristles is L1 and the difference in bristle length between the two half tufts is L2, the numerical value expressed as L2/L1 is 0.08 or more and 4.0 or less.

Furthermore, in the toothbrush according to one aspect of the present invention, the tip of the branched bristles is branched into two or more branches.

Furthermore, in the toothbrush according to one aspect of the present invention, the diameter of the bristles is 6 mil or more and 9 mil or less.

Furthermore, in the toothbrush according to one aspect of the present invention, the diameter of the second bristles that make up the inner bristle bundle is 5 mil or more and 7 mil or less.

The present invention provides a toothbrush that is gentle on the gums and contributes to improved cleaning power.

1 is a diagram showing an embodiment of the present invention, and is a front view showing a part of a toothbrush. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. 10 is a partially enlarged view of the area around the branched portion of the tip-branched hair 22. FIG. 10 is a partially enlarged view of a modified example of the tip-branched hair 22. FIG. 10 is a partially enlarged view of a modified example of the tip-branched hair 22. FIG. 10 is a partially enlarged view of a modified example of the tip-branched hair 22. FIG. 10 is a partially enlarged view of a modified example of the tip-branched hair 22. FIG. 10 is a partially enlarged view of a modified example of the tip-branched hair 22. FIG. 10 is a partially enlarged view of a modified example of the tip-branched hair 22. FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a toothbrush according to the present invention will now be described with reference to FIGS.
The following embodiment shows one aspect of the present invention, does not limit the present invention, and can be modified as desired within the scope of the technical concept of the present invention. In addition, in the following drawings, the scale and number of each structure are different from the actual structure to make each configuration easier to understand.

FIG. 1 is a front view showing a portion of a toothbrush 10 according to the present embodiment.
As shown in FIG. 1, the toothbrush 10 is formed by integrally molding a handle body 2 and a head portion 3 extending from the handle body 2 .

One side of the head unit 3 is the bristle-implanted surface 3a, on which multiple bristle bundles are planted. In this embodiment, the bristle-implanted surface 3a of the head unit 3 is provided with a brush 4 made up of bristle bundles with three different heights.

In the following description, the thickness direction of the head portion 3, which is perpendicular to the bristle-implanted surface 3a, is referred to as the Z direction; the length direction of the head portion 3, which is the direction in which the handle body 2 extends, is referred to as the Y direction; and the width direction of the head portion 3, which is perpendicular to the Y and Z directions, is referred to as the X direction. Furthermore, in the Z direction, the side of the bristle-implanted surface 3a will be referred to as the front side, and the side opposite the bristle-implanted surface 3a will be referred to as the back side, as appropriate.

The thickness, length, and width of the head portion 3 are not particularly limited. The thinner the head portion 3, the easier it is to operate in the oral cavity; however, if it is too thin, the strength of the head portion 3 is likely to be insufficient. Therefore, the thickness of the head portion 3 can be determined taking into consideration the material of the handle body 2, and is preferably, for example, 1.5 mm or more and 5 mm or less, and more preferably 2 mm or more and 3 mm or less.

The brush 4 is composed of a plurality of outer bristle bundles 20 arranged on the outermost periphery and a plurality of inner bristle bundles 30 arranged inside the outer bristle bundles 20.
The outer tufts 20 are implanted in each of the tufting holes 5 provided on the periphery of the implantation surface 3a to form an outer tuft group surrounding the inner tufts 30. The inner tufts 30 are implanted in a plurality of tufting holes 6 provided closer to the center of the implantation surface 3a and more inward than the tufting holes 5 to form an inner tuft group. In this embodiment, the tufting holes 5, 6 are arranged in a lattice pattern.

FIG. 2 is a cross-sectional view taken along line AA in FIG.
2, the outer bristle bundle 20 has a half bristle bundle 21a and a half bristle bundle 21b of different bristle lengths. The bristle length is the distance in the Z direction from the implantation surface 3a to the tip of the outer bristle bundle 20. That is, the outer bristle bundle 20 is composed of a plurality of bristles 22 implanted with a difference in height between the half bristle bundle 21a and the half bristle bundle 21b on either side of the flat line 7.

Specifically, a flat wire 7 is sandwiched between the folded outer hair bundles 20, and this flat wire 7 is driven into the tufting hole 5, thereby implanting the outer hair bundles 20 on the tufting surface 3a of the head unit 3. In this embodiment, as shown in Figure 1, all flat wires 7 are driven into the tufting hole 5 at a predetermined angle with respect to the longitudinal direction (Y direction) of the head unit 3. The orientation of each flat wire 7 is uniform.

The angle of the flat line 7 is not particularly limited, but it is preferably between 0 and 45 degrees relative to the length of the head.

Half hair bundle 21a is positioned on the outer periphery. Half hair bundle 21b is positioned more inward than half hair bundle 21a. The hair length of half hair bundle 21a is shorter than the hair length of half hair bundle 21b. In other words, the outer hair bundle 20, which includes half hair bundle 21a and half hair bundle 21b, is folded asymmetrically across the flat line 7 and implanted.

The inner hair bundle 30 has a half hair bundle portion 31a and a half hair bundle portion 31b. Each of the multiple inner hair bundles 30 is also made up of multiple second bristles 32, with one half hair bundle portion 31a and the other half hair bundle portion 31b planted on either side of the flat wire 7.

Specifically, a flat wire 7 is sandwiched between the folded inner hair bundles 30, and this flat wire 7 is driven into the tufting hole 6, thereby implanting the inner hair bundles 30 on the tufting surface 3a of the head portion 3. In this embodiment, as shown in Figure 1, all flat wires 7 are driven into the tufting hole 6 at a predetermined angle with respect to the longitudinal direction (Y direction) of the head portion 3. The orientation of each flat wire 7 is uniform.

Half hair bundle 31a is positioned further outward than half hair bundle 31b. The hair length of half hair bundle 31a is the same as that of half hair bundle 31b. In other words, the inner hair bundle 30, which includes half hair bundle 31a and half hair bundle 31b, is folded symmetrically across the flat line 7 and implanted.

The bristle length of half bristle bundles 31a and 31b is, for example, 12 mm. The bristle length of half bristle bundles 31a and 31b is longer than the bristle length of half bristle bundles 21a and 21b. Therefore, the brush 4 has the longest bristles in the center in the X direction (width direction), and the bristle length gradually decreases toward the outer periphery in the X direction, resulting in a dome-shaped tip when viewed in the Y direction. In other words, the bristle length of the inner bristle bundles 30 is longer than the bristle length of the outer bristle bundles 20. By making the bristle length of the inner bristle bundles 30 longer than the bristle length of the outer bristle bundles 20, the brush is designed to fit snugly around the cervical area, improving the cleaning feel and cleaning power of periodontal pockets.

The second bristles 32 constituting the inner bristle bundle 30 are not particularly limited, but may include straight bristles, double-ended ST bristles (tapered bristles whose diameter gradually narrows toward the tip), spiral ST bristles (spiral tapered bristles whose diameter gradually narrows toward the tip), and branched bristles (feather bristles, tapered branched bristles) described below. In this embodiment, ST bristles are used as the second bristles 32 constituting the inner bristle bundle 30. By constructing the inner bristle bundle 30 from ST bristles, the cleaning power of periodontal pockets can be improved. Spiral ST bristles are twisted longitudinally to form a helical ridge on the outer periphery. When force or vibration is applied in a bending direction to the multiple bristles in the bundle, the bristles come into contact with each other, generating friction, making the bristles less likely to bend. This provides the bundle of bristles with appropriate rigidity, increasing the strength of the bristles. On the other hand, because the diameter of the bristles tapers towards the tip, the tips of the bristles do not interfere with each other, and the area near the tips of the bristles can reach deep into the periodontal pocket. For this reason, by configuring the inner bristle bundle 30 with spiral ST bristles, the cleaning power of the periodontal pocket can be further improved.

The bristle diameter of the second bristles 32 that make up the inner bristle bundle 30 is not particularly limited, but it is preferably 5 mil or more and 7 mil or less in order to improve the feel on the gums and cleaning power.

In this embodiment, the bristles 22 that make up the outer bristle bundles 20 are bifurcated bristles (hereinafter referred to as bifurcated bristles 22) with the tips of the bristles 22 bifurcated on both sides of the length. By making the outer bristle bundles 20 out of bifurcated bristles 22, it is possible to improve the gentle feel on the gums.

Examples of the branched tip hairs 22 include feathered hairs in which the tip of a hollow filament has been cut, or tapered branched hairs in which the diameter of each branch decreases toward the tip. In this embodiment, tapered branched hairs in which the branched parts taper toward the tip are used as the branched tip hairs 22.

The branched-tip bristles 22 are branched at the tip of the bristles, with each branch having a thin tip. The branched bristles flex to provide cushioning, resulting in less stiffness and less pain when they come into contact with the gums. Furthermore, the branched-tip bristles 22 are folded asymmetrically across the flat line 7, creating a difference in hair length between the half hair bundles 21a and 21b. Creating a difference in hair length between the half hair bundles 21a and 21b reduces interference between the branches, improving cushioning when they come into contact with the gums.

Furthermore, due to the difference in hair length between half hair bundle 21a and half hair bundle 21b, when the bristles come into contact with the gums, half hair bundle 21b, which has a longer hair length, comes into contact first, followed by half hair bundle 21a, which has a shorter hair length. As a result, the bristles rise even lower when they come into contact with the gums, further reducing pain.

In addition, tapered branched bristles are used as the tip branched bristles 22, which improves the feel and contributes to improved cleaning power of periodontal pockets.

The bristle diameter of the branched bristles 22 (the bristles that are not branched) that make up the outer bristle bundles 20 is not particularly limited, but it is preferably 6 mil or more and 9 mil or less in order to improve the feel on the gums and cleaning power.

FIG. 3 is a partially enlarged view of the area around the branched portion of the tip branched hair 22.
3, the tip of the tip-branched hair 22 has a branched portion 22a and a branched portion 22b. The branched portion 22a constitutes a part of the half hair bundle portion 21a. The branched portion 22b constitutes a part of the half hair bundle portion 21b.

The number of branches in branch portions 22a and 22b is not particularly limited, but is preferably two or more branches (three branches in Figure 3), more preferably two or more branches and 20 or less branches, even more preferably two or more branches and 15 or less branches, and even more preferably two or more branches and 7 or less branches. Increasing the number of branches can improve the feel of branches 22a and 22b when they come into contact with the gums.

The branched portion 22a and the branched portion 22b are formed to have the same branch length (length in the Z direction) L1.
The branch length L1 of the branch portions 22a and 22b is preferably 0.5 mm or more, more preferably 1.0 mm or more, and even more preferably 1.5 mm or more. The branch length L1 of the branch portions 22a and 22b is preferably 6.0 mm or less, more preferably 4.0 mm or less, even more preferably 3.0 mm or less, particularly preferably 2.5 mm or less, and most preferably 2.0 mm or less.
The length of the bristles 22 including the branched portion 22a is shorter than the length of the bristles 22 including the branched portion 22b. That is, the length of the half hair bundle 21a is shorter than the length of the half hair bundle 21b.

By making the bristles of half tuft 21a shorter than those of half tuft 21b, the difference in height is gentle no matter which direction you brush, improving the comfort of the brush 4 when it comes into contact with the gums.

The difference L2 between the hair length of the bristles 22 including the branched portion 22a and the hair length of the bristles 22 including the branched portion 22b (the difference between the hair length of the half hair bundle 21a and the half hair bundle 21b) is preferably 0.5 mm or more and 2.0 mm or less, more preferably 0.5 mm or more and 1.5 mm or less, and even more preferably 0.5 mm or more and 1.0 mm or less. That is, the lower limit of the hair length difference L2 is preferably 0.5 mm or more, and more preferably 0.75 mm or more. Moreover, the upper limit of the hair length difference L2 is preferably 2.0 mm or less, more preferably 1.5 mm or less, and even more preferably 1.0 mm or less.
If the bristle length difference L2 is less than 0.5 mm, the area where the branches 22a and 22b interfere with each other in the outer bristle bundle 20 when the bristle tips bend becomes longer, which may reduce the cushioning function and impair the feel of the brush. If the bristle length difference L2 exceeds 2.0 mm, the length over which the branches 22b are supported by the branches 22a in the outer bristle bundle 20 becomes shorter, which reduces the bristle stiffness and may make it difficult to ensure oral cleaning power. Furthermore, even if the bristle tips of the branches 22b bend, the branches 22a are less likely to come into contact with the gums, which may result in localized pressure on the gums and impair the feel of the brush. Therefore, by setting the bristle length difference L2 to 0.5 mm or more and 2.0 mm or less, it is possible to improve the feel of the brush and the cleaning power.

The value represented by L2/L1 is preferably 0.08 or more and 4.0 or less, more preferably 0.17 or more and 3.0 or less, and even more preferably 0.17 or more and 2.0 or less.
That is, the lower limit of the numerical value represented by L2/L1 is preferably 0.08 or more, and more preferably 0.17 or more.
The upper limit of the numerical value represented by L2/L1 is preferably 4.0 or less, more preferably 3.0 or less, and even more preferably 2.0 or less.
If the value represented by L2/L1 is less than 0.08, the area where the branches 22a and 22b interfere with each other in the outer bristle bundle 20 when the bristles bend becomes longer, which may reduce the cushioning function and impair the feel of the brush. If the value represented by L2/L1 exceeds 4.0, the length of the outer bristle bundle 20 supported by the branches 22a becomes shorter, which reduces the bristle stiffness and may result in an inability to ensure oral cleaning power. Furthermore, even if the bristles of the branches 22b bend, the branches 22a are less likely to come into contact with the gums, which may result in localized pressure on the gums and impair the feel of the brush. Therefore, by setting the value represented by L2/L1 to be 0.08 or more and 4.0 or less, it is possible to improve the feel of the brush and the cleaning power.

When the value represented by L2/L1 is less than 1.0, i.e., when the hair length difference L2 is smaller than the branch length L1 of the branch portion 22b that constitutes the maximum hair length, the branch portion 22a and the branch portion 22b overlap in the Z direction (hair length direction).
The overlap amount between branch portion 22a and branch portion 22b (i.e., L1-L2) is preferably 0.1 mm or more and 5.5 mm or less, more preferably 0.5 mm or more and 3.0 mm or less, and even more preferably 0.5 mm or more and 2.0 mm or less.
That is, the lower limit of the overlap amount is preferably 0.1 mm or more, and more preferably 0.5 mm or more.
The upper limit of the overlap amount is preferably 5.5 mm or less, more preferably 3.0 mm or less, and even more preferably 2.0 mm or less.
The overlap amount between branched portion 22a and branched portion 22b is preferably 0.8% or more and 61.1% or less of the maximum hair length, more preferably 3.8% or more and 33.3% or less, and even more preferably 3.8% or more and 22.2% or less.

The hair length of the bristles 22 including the branch portion 22a (hair length of the half hair bundle portion 21a) is, for example, 10 mm. The hair length of the bristles 22 including the branch portion 22b (hair length of the half hair bundle portion 21b) is, for example, 11 mm. Therefore, the hair length of the half hair bundle portion 21a and the half hair bundle portion 21b is shorter than the hair length of the inner hair bundle 30.

As described above, the toothbrush 10 of this embodiment has outer bristle bundles 20 arranged at the outermost periphery and inner bristle bundles 30 arranged inside the outer bristle bundles 20. The outer bristle bundles 20 are formed by folding in half branched bristles 22, which are bristles with branched ends on both sides of their length, into two half-bundle portions 21a, 21b with different bristle lengths, which contributes to improved feel and cleaning power.

[Example]
The present invention will be described in detail below with reference to examples. However, the present invention is not limited to the following examples and can be practiced with appropriate modifications within the scope of the present invention.

(Examples 1 to 6, Comparative Examples 1 to 3)
Samples of Examples 1 to 6 and Comparative Examples 1 to 3 were prepared according to the specifications shown in Table 1.
Specifically, with regard to the folding of the outer hair bundles, the samples of Examples 1 to 6 and Comparative Examples 2 and 3 were asymmetric (the hair lengths of the half hair bundles were different), while the sample of Comparative Example 1 was symmetric (the hair lengths of the half hair bundles were the same).

The bristles used for the inner bristles were branched straight bristles in the samples of Example 1 and Comparative Example 1, branched tapered bristles in the sample of Example 2, tapered bristles in the samples of Examples 3 to 5 and Comparative Example 3, spiral tapered bristles in the sample of Example 6, and straight bristles in the sample of Comparative Example 2.

The hair used for the outer hair bundles was branched straight hair for the samples of Example 1 and Comparative Example 1, branched tapered hair for the samples of Examples 2 to 6, tapered hair for the sample of Comparative Example 3, and straight hair for the sample of Comparative Example 2.

Regarding the relationship between the maximum hair length of the outer hair bundle and the maximum hair length of the inner hair bundle, the samples of Examples 1 to 3 and Comparative Examples 1 to 3 had the same maximum hair length of the outer hair bundle and the maximum hair length of the inner hair bundle, while the samples of Examples 4 to 6 had the maximum hair length of the inner hair bundle longer than the maximum hair length of the outer hair bundle.

Regarding the relationship between the hair lengths of the half hair bundles in the outer hair bundles, in samples of Examples 1 to 4 and Comparative Examples 2 and 3, the hair length of the half hair bundle on the outer periphery is longer than the hair length of the inner half hair bundle on only one side of the head width; in samples of Examples 5 and 6, the hair length of the half hair bundle on the outer periphery is longer than the hair length of the inner half hair bundle on both sides of the head width; and in sample of Comparative Example 1, the hair length of the half hair bundle on the outer periphery is the same as the hair length of the inner half hair bundle.

The dimensions of each example are evaluated below.
Example 1
Inner hair bundle diameter: 6.5 mil
Branched straight hair: 5 branches, L1 = 2 mm
・Maximum hair length = 12mm
Outer hair bundle diameter: 8.0 mil
Branched straight hair: 5 branches, L1 = 2 mm
Folded (asymmetric): L2 = 1 mm, L1 - L2 = 1 mm, as shown in Figure 3.
・Hair length: Half hair bundle 21b = 12mm, Half hair bundle 21a = 11mm

Example 2
Inner hair bundle diameter: 6.5 mil
Branched tapered hair: 3 branches, L1 = 2 mm
・Maximum hair length = 12mm
Outer hair bundle diameter: 8.0 mil
Branched tapered hair: 3 branches, L1 = 2 mm
Folded (asymmetric): L2 = 1 mm, L1 - L2 = 1 mm, as shown in Figure 3.
・Hair length: Half hair bundle 21b = 12mm, Half hair bundle 21a = 11mm

Example 3
Inner hair bundle diameter: 6.5 mil
Tapered hair: Number of branches: 0, L1 = 0 mm
・Maximum hair length = 12mm
Outer hair bundle diameter: 8.0 mil
Branched tapered hair: 3 branches, L1 = 2 mm
Folded (asymmetric): L2 = 1 mm, L1 - L2 = 1 mm, as shown in Figure 3.
・Hair length: Half hair bundle 21b = 12mm, Half hair bundle 21a = 11mm

Example 4
Inner hair bundle diameter: 6.5 mil
Tapered hair: Number of branches: 0, L1 = 0 mm
・Maximum hair length = 12mm
Outer hair bundle diameter: 8.0 mil
Branched tapered hair: 3 branches, L1 = 0 mm
Folded (asymmetric): L2 = 1 mm, L1 - L2 = 1 mm, as shown in Figure 3.
・Hair length: Half hair bundle 21b = 11mm, Half hair bundle 21a = 10mm

Example 5
Inner hair bundle diameter: 6.5 mil
Tapered hair: Number of branches: 0, L1 = 0 mm
・Maximum hair length = 12mm
Outer hair bundle diameter: 8.0 mil
Branched tapered hair: 3 branches, L1 = 2 mm
Folded (asymmetric): L2 = 1 mm, L1 - L2 = 1 mm, as shown in Figure 3.
・Hair length: Half hair bundle 21b = 11mm, Half hair bundle 21a = 10mm

Example 6
Inner hair bundle diameter: 6.5 mil
Spiral tapered hair: Number of branches: 0, L1 = 0 mm
・Maximum hair length = 12mm
Outer hair bundle diameter: 8.0 mil
Branched tapered hair: 3 branches, L1 = 2 mm
Folded (asymmetric): L2 = 1 mm, L1 - L2 = 1 mm, as shown in Figure 3.
・Hair length: Half hair bundle 21b = 11mm, Half hair bundle 21a = 10mm

(Comparative Example 1)
Inner hair bundle diameter: 6.5 mil
Branched straight hair: 5 branches, L1 = 2 mm
・Maximum hair length = 12mm
Outer hair bundle diameter: 8.0 mil
Branched straight hair: 5 branches, L1 = 2 mm
Folding (symmetric): L2 = 0 mm
・Hair length: Half hair bundle 21b = Half hair bundle 21a = 12mm

(Comparative Example 2)
Inner hair bundle diameter: 6.5 mil
Straight hair: 0 branches, L1 = 0 mm
・Maximum hair length = 12mm
Outer hair bundle diameter: 8.0 mil
Straight hair: 0 branches, L1 = 0 mm
Folding (asymmetric): L2 = 1 mm
・Hair length: Half hair bundle 21b = 12mm, Half hair bundle 21a = 11mm

(Comparative Example 3)
Inner hair bundle diameter: 6.5 mil
Tapered hair: Number of branches: 0, L1 = 0 mm
・Maximum hair length = 12mm
Outer hair bundle diameter: 8.0 mil
Tapered hair: Number of branches: 0, L1 = 0 mm
Folding (asymmetric): L2 = 1 mm
・Hair length: Half hair bundle 21b = 12mm, Half hair bundle 21a = 11mm

[Evaluation items]
The samples of Examples 1 to 6 and Comparative Examples 1 to 3 were evaluated for toothbrush feel, cleaning performance, and periodontal pocket cleaning power.

[Evaluation method]
<Evaluation of touch>
A panel of 10 experts cleaned the oral cavity with each toothbrush and evaluated the feel of the toothbrush on the gums using the following evaluation criteria. The following evaluations were made based on the average scores of the 10 experts. An average score of 5.5 or more by the 10 experts was rated as "◎ (Very Good)", an average score of 4.0 to less than 5.5 was rated as "○ (Good)", an average score of 2.5 to less than 4.0 was rated as "△ (Not Bad)", and an average score of less than 2.5 was rated as "× (Bad)".
<Evaluation criteria>
7 points: Very comfortable to touch.
6 points: The feel is quite good.
5 points: The feel is somewhat good.
4 points: Neither.
3 points: The feel is a little uncomfortable.
2 points: The feel is quite bad.
1 point: Very uncomfortable to touch.

<Evaluation of cleaning experience>
A panel of 10 experts cleaned the oral cavity with each toothbrush and evaluated the cleaning sensation (cleaning sensation throughout the oral cavity) using the following evaluation criteria. The following evaluation was made based on the average scores of the 10 experts. An average score of 5.5 or more by the 10 experts was rated as "◎ (Very Good)", an average score of 4.0 to less than 5.5 was rated as "○ (Good)", an average score of 2.5 to less than 4.0 was rated as "△ (Not Bad)", and an average score of less than 2.5 was rated as "× (Bad)".
<Evaluation criteria>
7 points: The cleaning effect is very good.
6 points: The cleaning effect is quite good.
5 points: Cleaning feels fairly good.
4 points: Neither.
3 points: Cleaning effect is somewhat poor.
2 points: The cleaning effect is quite poor.
1 point: The cleaning effect is very poor.

<Evaluation of periodontal pocket cleaning ability>
A panel of 10 experts cleaned the oral cavity with each toothbrush and evaluated the cleaning effect on periodontal pockets using the following evaluation criteria. The following evaluations were made based on the average scores of the 10 experts. An average score of 6.0 or more by the 10 experts was designated as "◎+ (Special Good)," 5.5 to less than 6.0 as "◎ (Very Good)," 4.0 to less than 5.5 as "○ (Good)," 2.5 to less than 4.0 as "△ (Not Bad)," and less than 2.5 as "× (Bad)."
<Evaluation criteria>
7 points: There is a very strong feeling that dirt has been removed from the periodontal pockets.
6 points: I can feel that the dirt in my periodontal pockets has been removed quite strongly.
5 points: There is a strong feeling that dirt has been removed from the periodontal pockets.
4 points: Neither.
3 points: I don't really feel like the dirt in my periodontal pockets has been removed.
2 points: There is almost no feeling that dirt has been removed from the periodontal pockets.
1 point: No feeling of dirt being removed from the periodontal pocket.

As shown in Table 1, the samples of Examples 1 to 6, in which the outer bristle bundles are formed with bristles that branch at the ends and are folded asymmetrically so that the bristle lengths of the half-tufts are different, received favorable ratings in terms of feel, cleaning performance, and periodontal pocket cleaning ability.

In contrast, the sample of Comparative Example 1, in which the outer bristle bundles were folded symmetrically and the bristle lengths of the half-tufts were the same, even though the outer bristle bundles were formed with bristles at the ends, did not receive a good rating for feel. Furthermore, the samples of Comparative Examples 2 and 3, in which the outer bristle bundles were folded asymmetrically but were not formed with bristles at the ends, also did not receive a good rating for feel. Furthermore, the sample of Comparative Example 2, in which the inner bristle bundles were straight, did not receive a good rating for periodontal pocket cleaning ability.

In addition, the samples of Examples 3 to 6, in which the inner bristles are formed with tapered bristles, received better evaluations for periodontal pocket cleaning ability than the samples of Examples 1 and 2, in which the inner bristles are formed with branched bristles at the ends. Furthermore, the samples of Examples 4 to 6, in which the maximum bristles length of the inner bristles is longer than the maximum bristles length of the outer bristles, received better evaluations for cleaning feel than the samples of Examples 1 to 3, in which the maximum bristles length of the outer bristles is the same as the maximum bristles length of the inner bristles.

The samples of Examples 2 to 6, in which the outer bristles were formed with branched tapered bristles, were evaluated as more comfortable to touch than the sample of Example 1, in which the outer bristles were formed with branched straight bristles. The samples of Examples 5 and 6, in which the bristles of the half bristles on the outer periphery were made longer than the bristles of the inner half bristles on both sides of the head in the width direction, were evaluated as more comfortable to touch than the samples of Examples 1 to 4, in which the bristles of the half bristles on the outer periphery were made longer than the bristles of the inner half bristles on only one side of the head in the width direction.
Example 6, in which the bristles of the inner bristle bundle of Example 5 were changed from tapered bristles to spiral tapered bristles, received an even better evaluation than Example 5 regarding the periodontal pocket cleaning power.

The above describes preferred embodiments of the present invention with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to these examples. The shapes and combinations of the components shown in the above examples are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

For example, in the above embodiment, the branched portion 22a and the branched portion 22b have the same branched length L1, and the bristle length of the bristles 22 including the branched portion 22a is shorter than the bristle length of the bristles 22 including the branched portion 22b. However, this configuration is not limited to this. For example, as shown in FIG. 4, the branched length L3 of the branched portion 22a may be shorter than the branched length L1 of the branched portion 22b, and the bristle length difference L2 may be shorter than the branched length L1 of the branched portion 22b.

Alternatively, as shown in Figure 5, the branch length L3 of branch portion 22a may be longer than the branch length L1 of branch portion 22b, and the hair length difference L2 may be shorter than the branch length L1 of branch portion 22b. Furthermore, as shown in Figure 6, branch portion 22a and branch portion 22b may have the same branch length L1, and the hair length difference L2 may be longer than branch length L1. Alternatively, as shown in Figure 7, branch portion 22a and branch portion 22b may have the same branch length L1, and the hair length difference L1 may be the same as branch length L1.

Alternatively, as shown in Figure 8, the branch length L3 of branch portion 22a may be shorter than the branch length L1 of branch portion 22b, and the hair length difference L2 may be longer than the branch length L1 of branch portion 22b. Furthermore, as shown in Figure 9, the branch length L3 of branch portion 22a may be longer than the branch length L1 of branch portion 22b, and the hair length difference L2 may be longer than the branch length L1 of branch portion 22b.

4 and 5, the branch length L1 of the branch 22b that constitutes the maximum bristle length is greater than the bristle length difference L2, so that the branch 22a and the branch 22b overlap in the Z direction as described above. As shown in Fig. 4, when L1 > (L2 + L3), the overlap amount is the branch length L3.
The overlap amount L3 is preferably 0.5 mm or more and 5.5 mm or less, more preferably 0.5 mm or more and 3.0 mm or less, and even more preferably 0.5 mm or more and 2.0 mm or less.
The overlap amount L3 is preferably 3.8% to 61.1% of the maximum hair length, more preferably 3.8% to 33.3%, and even more preferably 3.8% to 22.2%.
In FIG. 4, when L2<L1≦(L2+L3) (that is, in the case of the embodiment of FIG. 5), it is also preferable to select the overlap amount as described above.

2...Handle body, 3...Head portion, 3a...Hair implantation surface, 20...Outer hair bundle, 21a, 21b...Half hair bundle portion, 22...Hair (branched tip hair), 22a, 22b...Branched portion, 30...Inner hair bundle, 32...Second hair bundle

Claims (7)

The brush has a head portion having a plurality of tufts of bristles planted on a bristle planting surface, and a handle body extending from the head portion,
The hair bundles include outer hair bundles arranged on the outermost periphery and inner hair bundles arranged inside the outer hair bundles,
The outer hair bundle is formed by folding in two end-branched hairs, the ends of which are branched on both sides in the length direction, and has two half hair bundle portions with different hair lengths, and the hair length of one half hair bundle portion provided on the outer side is shorter than that of the other half hair bundle portion provided on the inner side,
the tip-branched hairs of the two half hair bundle portions are tapered hairs tapered toward the tip,
When the branched length of the tip-branched hair is L1 and the difference in maximum hair length between the two half hair bundle portions is L2, the numerical value represented by L2/L1 is 0.08 or more and less than 1.0 ,
L1>L2, and the value represented by L1-L2 is 0.1 mm or more and 5.5 mm or less ,
The flat line is sandwiched between the folded outer hair bundles at an angle of 0 to 45 degrees relative to the head length direction,
A toothbrush characterized in that the head portion has at least four rows of bristle holes aligned in the width direction . the inner bristle bundle has a plurality of second bristles,
The second bristles are tapered bristles that taper toward the tip.
The toothbrush of claim 1. The hair length of the inner hair bundle is longer than the hair length of the outer hair bundle.
The toothbrush according to claim 1 or 2. The difference in maximum hair length between the two half hair bundle portions is 0.5 mm or more and 2.0 mm or less.
4. The toothbrush according to claim 1. The tip of the branched hair is branched into two or more.
5. The toothbrush according to any one of claims 1 to 4 . The diameter of the bristles is 6 mil or more and 9 mil or less.
6. The toothbrush according to any one of claims 1 to 5 . The diameter of the second bristles constituting the inner bristle bundle is 5 mil or more and 7 mil or less.
The toothbrush of claim 2 .