JP2006130012A - Toothbrush - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toothbrush capable of effectively exhibiting a dental plaque removing effect and a color stain removal effect, etc. by bristles with lozenge-shaped cross-sections while keeping the excellent using feel. <P>SOLUTION: The toothbrush 10 has a brush part 16 consisting of a plurality of bristle tufts 15a, 15b and 15c. The top line s connecting the tops of the bristle tufts 15a, 15b and 15c has a waveform-shaped part 17 with a small curved recess part 17a whose curving is sharp and a continued large curved recess 17b whose curving is gentle as the brush part 16 is seen from a side. The lozenge-shaped tufts 15a consisting of bristles 14a with lozenge-shaped cross-sections are included in the small curved recess part 17a and the large curved recess part 17b. The lozenge-shaped bristle tufts 15a are planted in the longitudinal direction X of the brush part 16 with another circular tuft 15c, consisting of bristles 14a with circular cross-sections, interposed between the tufts 15a. Further, auxiliary lozenge-shaped bristle tufts 15b consisting of bristles 14a with lozenge-shaped cross-sections are planted at the head end and the rear end in the longitudinal direction X of the brush part 16. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a toothbrush, and more particularly to a toothbrush that includes a bristle bundle made of a diamond-shaped cross-section bristle in a brush portion.

  A toothbrush has a plurality of bristle bundled by fixing a bunch of bristles by, for example, placing a flat wire into a plurality of flock holes provided in a flocking table or fusing them with heat. It is obtained by forming a brush portion made of a bundle. In addition, the toothbrush is designed to efficiently perform appropriate cleaning according to the tooth part such as the tooth surface part, interdental part, and tooth neck part, and the type of tooth such as the front tooth and the back tooth. Various ideas have been made on the arrangement, the overall shape of the brush portion, the shape of the bristle, and the like.

For example, a toothbrush in which the cross-sectional shape of the bristle constituting the bristle bundle has a square shape, a substantially star shape, a hexagonal shape, or the like is disclosed. However, it becomes possible to effectively remove the plaque accumulated in the interdental portion by acting as a scraper (see, for example, Patent Document 1).
JP-A-6-169816

  In addition, a toothbrush using a bristle having a rhombus (including a parallelogram shape similar to a rhombus) as a bristle constituting a bristle bundle has a large contact area with the smooth surface of the tooth, and the tooth Since it is easy for bristles to enter the gaps, it is effective in removing plaque.

  However, when a toothbrush having a bristles with a diamond-shaped cross-section bristles is used, the above-described effects can be obtained. On the other hand, a bunch of bristles with a rhombus-shaped cross-section bristles has a hard feel and a poor feeling of use. . In order to enhance the feeling of use with such a toothbrush, it is conceivable to reduce the bristle bristle diameter and the bundle diameter of the bristle bundle. However, in these methods, the above-described operational effects of the diamond-shaped cross-sectional bristle are sufficiently exhibited. And the durability of the hair bundle is inferior.

  An object of the present invention is to provide a toothbrush that can effectively remove plaque and colored stains by using a diamond-shaped cross-section bristle while maintaining a good feeling of use.

The present invention has a brush portion composed of a plurality of hair bundles, and when the brush portion is viewed from the side, the tip line connecting the tips of the hair bundles has a small curved concave portion with a sharp curve and a gentle curve. A toothbrush having a wave-shaped portion that is continuously connected to a large curved concave portion, and each of the small curved concave portion and the large curved concave portion has a rhomboid hair bundle in which 80 to 100% of all the bristle is a diamond-shaped cross-sectional bristle. The rhombus hair bundle is provided by providing a toothbrush having a hair bundle made of bristles having a regular polygonal cross section of a circle or a hexagon in the longitudinal direction of the brush portion. The above objective has been achieved.
In the present invention, the rhomboid hair bundle means a hair bundle in which 80 to 100% of all the bristle is a rhombus cross-section bristle, and the circular bristle means a hair bundle made of a circular or hexagonal or more regular polygon cross-section bristles. .

  According to the toothbrush of the present invention, it is possible to effectively exhibit the removal of plaque and colored stains by the diamond-shaped cross-section bristle while maintaining a good feeling of use.

  A preferred first embodiment of the present invention will be described. As shown in FIGS. 1A to 1C, the toothbrush 10 according to the first embodiment includes a flocking table of a toothbrush main body including a gripping part (not shown), a flocking table 11, and a neck 12 connecting them. The hair bundles (tufts) 15a, 15b, 15c formed by bundling a plurality of bristles 14a, 14b are respectively planted (planted) in the plurality of hair-planting holes 13a, 13b formed in FIG. Here, according to the first embodiment, the first flocking hole 13a is a circular flocking hole having a large diameter of, for example, 1.7 to 2.5 mm, and the first flocking hole 13a includes The rhombus hair bundle 15a or the auxiliary rhombus hair bundle 15b in which the rhombic cross-sectional bristle 14a is bundled is implanted. The second flocking hole 13a is a circular flocking hole having a diameter smaller than that of the first flocking hole 13a having a diameter of 1 to 1.6 mm, for example. The second flocking hole 13a has a circular shape. A circular hair bundle 15c in which the cross-sectional bristle 14b is bundled is implanted.

  And the toothbrush 10 of this 1st Embodiment has the brush part 16 which consists of several hair | bristle bundle 15a, 15b, 15c, and when the brush part 16 is seen from a side surface (refer FIG.1 (b)), bristle The tip line s connecting the tips of the bundles 15a, 15b, and 15c has a waveform in which a small curved concave portion 17a having a small maximum curvature radius and a sharp curvature and a large curved concave portion 17b having a large maximum curvature radius and a sharp curvature are connected. A shape portion 17 is provided. Each of the small curved concave portion 17a and the large curved concave portion 17b includes a rhombus hair bundle 15a composed of a diamond-shaped cross-section bristle 14a. The rhombic hair bundle 15a has a circular cross section in the longitudinal direction X of the brush portion 16. A circular hair bundle 15c made of bristle 14b is interposed.

  Furthermore, according to the first embodiment, the small curved concave portion 17a is disposed on the front end side in the longitudinal direction X of the brush portion 16, and the large curved concave portion 17b is disposed on the rear end side in the longitudinal direction X of the brush portion 16, An auxiliary rhombus hair bundle 15b made of a diamond-shaped cross-section bristle 14a is provided at the tip of the brush portion 16 in the longitudinal direction X.

  Furthermore, according to the first embodiment, the rhombus hair bundle 15a and the auxiliary rhombus hair bundle 15b are 0.5 to 5 degrees on the center side in the width direction Y or the longitudinal direction X of the brush portion 16. It is inclined and provided from a direction perpendicular to the flocking table 11 (see the arrow in FIG. 1A).

  The toothbrush body is made of, for example, a synthetic resin such as polypropylene or ABS resin. According to the first embodiment, the flat surface of the flocking table 11 has three first flocked holes at the tip in the longitudinal direction X. 13a is formed in the opening, and in the rear part of these first flocking holes 13a, three rows in the width direction Y of the brush portion 16 and a total of eight second flocking holes 13b are formed. In addition, at the rear part of these second flocking holes 13b, one row and two first flocking holes 13a are formed in the width direction Y of the brush portion 16, and further behind these first flocking holes 13a. The part is formed with a total of eight second flocking holes 13 b in three rows in the width direction Y of the brush portion 16. And in the rear part of these 2nd flocking holes 13b, it is located in the rear-end part of longitudinal direction X of brush part 16, and the 1st flocking hole 13a of 1 row and 2 places in the width direction Y of brush part 16 Is formed as an opening.

  These flocked holes 13a and 13b each have a depth of about 2 to 4.5 mm, for example, and each flocked hole 13a and 13b has a rhombus hair bundle 15a, an auxiliary rhombus hair bundle 15b, or a circular hair. The bundle 15c is planted with a bristle length of 7 to 15 mm from the surface of the flocking table 11, for example, by a method of driving a flat wire or a method of fusing with a heat. That is, of the three first flock holes 13a at the tip portion, an auxiliary rhombus hair bundle 15b is planted in the first flock hole 13a at the tip, and the width direction Y of the brush portion 16 is set. A rhombic hair bundle 15a is implanted in the remaining two first flocking holes 13a in one row. Further, circular hair bundles 15c are planted in the eight second flock holes 13b at the back of these rhombic hair bundles 15a, and the two first flock holes 13a at the back of these circular hair bundles 15c are A rhombus 15a is planted. Furthermore, circular hair bundles 15c are implanted in the eight second flock holes 13b behind these rhombic hair bundles 15a, and in the two first flock holes 13a behind these circular hair bundles 15c. The rhombus hair bundle 15a is planted at the rear end of the brush portion 16.

  As described above, the rhombus hair bundle 15a, the auxiliary rhombus hair bundle 15b, and the circular hair bundle 15c are planted on the flock base 11 of the toothbrush 10, so that the rhombus hair bundle 15a and the auxiliary rhombus hair bundle 15b have an area. By ratio, it occupies an area of 25-75% of the sum total of the areas of all the hair bundles 15a, 15b, 15c constituting the brush portion 16. Here, the area of each hair bundle 15a, 15b, 15c is equivalent to the cross-sectional area in the root part of each hair bundle 15a, 15b, 15c, and these 1st flock hole 13a and 2nd flock hole 13b by which these are planted. It is calculated through the opening area. According to the first embodiment, the rhombic hair bundles 15a and 15b including the auxiliary rhombus hair bundle 15b are included in the plurality of hair bundles 15a, 15b and 15c constituting the brush portion 16 in an area ratio of 25 to 50%. It is preferable that it is contained, and it is more preferable that 30 to 45% is contained. Since the rhomboid hair bundles 15a and 15b are included in the whole hair bundles 15a, 15b and 15c in an area ratio of 25 to 75%, an advantage of being effective in removing plaque can be obtained.

  Further, according to the first embodiment, as described above, the rhombic hair bundle 15a, the auxiliary rhombus hair bundle 15b, and the circular hair bundle 15c are planted on the flocking table 11 of the toothbrush 10, so that the rhombus hair The bundle 15a is divided into three rows in the width direction Y perpendicular to the longitudinal direction X of the brush portion 16 (one row for the small curved concave portion 17a and two rows for the large curved concave portion 17b), and a plurality (two in each row in the first embodiment). Place) will be arranged in a row.

  Further, according to the first embodiment, each pair of rhombic hair bundles 15 a arranged continuously in the width direction Y of the brush portion 16 is, for example, twice at the center side of the brush portion 17 in the width direction Y. The auxiliary rhombic hair bundle 15b is inclined at an angle from the direction perpendicular to the flocking table 11, and the auxiliary rhombic hair bundle 15b at the tip is, for example, at an angle of 2 degrees from the vertical direction to the center side in the longitudinal direction X of the brush portion 17. Inclined. According to the first embodiment, the rhombus hair bundle 15 a and the auxiliary rhombus hair bundle 15 b are perpendicular to the center side in the width direction Y or the longitudinal direction X of the brush portion 17 at an angle of 0.5 to 5 degrees. By being inclined from the direction, it is possible to obtain an advantage that the toothbrush is prevented from spreading while being effective in removing plaque.

  The rhombus cross-sectional bristle 14a constituting the rhombus hair bundle 15a or the auxiliary rhombus hair bundle 15b is a filament material made of synthetic resin such as nylon, for example, and as shown in FIG. 2 (a), parallel to the rhombus or rhombus. It has a quadrilateral cross-sectional shape. Moreover, as for the diamond-shaped cross-section bristle 14a, as for the hair diameter, for example, twice the cross-section secondary radius has a thickness of 6 to 10 mil (0.15 to 0.25 mm). By bundling several dozen, a rhombus hair bundle 15a having a bundle diameter of 1.7 to 2.5 mm, for example, corresponding to the opening shape of the first flocking hole 13a, or an auxiliary rhombus hair bundle 15b is formed. become.

  Here, as for the cross-sectional shape of the rhombus cross-sectional bristle 14a, it is preferable that the ratio of the long diagonal to the short diagonal in the two diagonals (long diagonal / short diagonal) is 1.2 to 1.9. When the ratio of the long diagonal line to the short diagonal line is 1.2 to 1.9, the advantage that the bristle easily enters the interdental region and the contact area of the bristle with the teeth is increased. In addition, the rhombus hair bundle 15a or the auxiliary rhombus hair bundle 15b can be used if the diamond cross-section bristle 14a is included in the bristle constituting the hair bundle 15a, 15b by 80 to 100%. The function as 15b can be sufficiently exhibited. In addition, according to this 1st Embodiment, in addition to the round process being given to the front-end | tip of each rhombus cross-sectional bristle 14a, it can also process into a taper shape.

  The circular cross-sectional bristle 14b constituting the circular hair bundle 15c is a filament material made of a synthetic material such as nylon or a natural material such as pig hair, and has a circular cross-section or hexagon as shown in FIG. It has the above regular polygon cross section. Moreover, the circular cross-section bristle 14b has a diameter of, for example, 6 to 10 mil (0.15 to 0.25 mm) as a bristle diameter. A circular hair bundle 15c having a bundle diameter of 1 to 1.6 mm, for example, corresponding to the opening shape of the second flocking hole 13b is formed. In addition, according to the first embodiment, the tip of each circular cross-section bristle 14b can be rounded, for example, or can be processed into a tapered shape or a spherical shape.

  According to the toothbrush 10 of the first embodiment, when the brush portion 16 is viewed from the side, the tip line s connecting the tips of the hair bundles 15a, 15b, and 15c has a sharp curvature and a maximum curvature radius. A corrugated portion 17 is provided in which a small small-curved concave portion 17a and a large-curved concave portion 17b having a large curvature radius and a large maximum curvature radius are connected. That is, according to the first embodiment, the brush portion 16 has the tips of the hair bundles 15a, 15b, and 15c in the cross section along the width direction Y as the same height, and the brush portion 16 is uneven on the tip surface along the width direction. In addition, the tip line s viewed from the side surface draws a waveform having three apexes 18a, 18b, and 18c. Further, a small curved concave portion 17a is formed by a concave portion between the front end top portion 18a and the intermediate top portion 18b so as to be bent, and a lower curved portion between the intermediate top portion 18b and the rear end top portion 18c is curved. The large curved concave portion 17b is formed by the concave portion.

  Furthermore, the small curved concave portion 17a and the large curved concave portion 17b are connected in the longitudinal direction X of the brush portion 16 via the intermediate curved convex surface 19 where the intermediate top portion 18b is located, thereby forming the corrugated portion 17. At the tip of the brush portion 16, an auxiliary rhombus hair bundle 15b is provided at one location adjacent to the rhombus hair bundle 15a disposed in the large curved concave portion 17b.

  Here, according to the first embodiment, the small curvature concave portion 17a has a maximum curvature radius of 0.5 to 2.5 mm, preferably 0.6 to 2 mm, in a portion curved downward. The curved concave portion 17b has a maximum radius of curvature of 2.6 mm or more, preferably 2.6 to 10 mm, at a portion that curves downward. Since the maximum curvature radius of the small curved concave portion 17a is 0.5 to 2.5 mm, an advantage that the concave portion and the interdental portion on the back side of the tooth can be efficiently cleaned is obtained. Further, since the maximum radius of curvature of the large curved concave portion 17b is 2.6 mm or more, an advantage that the smooth surface of the teeth can be uniformly wiped is obtained. In addition, according to this embodiment, the length along the longitudinal direction X of the brush part 16 of the small curved recessed part 17a is 6-8 mm, and it followed the longitudinal direction X of the brush part 16 of the large curved recessed part 17b. The length is 9 to 13 mm. Further, the height difference between the top portions 18a, 18b, 18c of the tip line s and the bottom portions of the small curved concave portion 17a and the large curved concave portion 17b is 0.5 to 4 mm.

  And according to the toothbrush 10 in this 1st Embodiment provided with the above-mentioned structure, the plaque removal effect by the rhombus cross-sectional bristle 14a, the removal effect of a colored stain, etc. are exhibited effectively, maintaining a favorable usability. Can do. That is, the toothbrush 10 according to the first embodiment includes a wave-shaped portion 17 in which a small curved concave portion 17a having a small maximum radius of curvature and a large curved concave portion 17b having a large maximum radius of curvature are provided in series. The curved concave portion 17b includes rhombus hair bundles 15a each having a rhombic cross-sectional bristle 14b, and these rhombus hair bundles 15a are formed in the longitudinal direction X of the brush portion 17 with a circular hair bundle 15b comprising a circular cross-sectional bristle 14b. Even if the rhomboid hair bundle 15a is formed by the diamond-shaped cross-section bristle 14a, which is hard to feel, the circular hair bundle 15b interposed between the rhombic hair bundles 15a makes these hard feels. It is possible to effectively relax and improve the feeling of use. In addition, each of the small curved concave portion 17a and the large curved concave portion 17b includes a rhombus hair bundle 15a including a rhombic cross-sectional bristle 14b that has a large contact area with the smooth surface of the tooth and easily enters the tooth gap. As shown in FIGS. 3A to 3C, for example, the concave portion on the back side of the tooth can be effectively cleaned by the rhombic hair bundle 15a of the small curved concave portion 17a (see FIG. 3A). For example, the tooth surface or gap can be effectively wiped by the rhombic hair bundle 15a of the small curved concave portion 17a and the large curved concave portion 17b (see FIG. 3B). The rhombic hair bundle 15a of the concave portion 17a can be effectively cleaned (see FIG. 3 (c)), and an excellent plaque removal effect, colored stain removal effect, and the like can be obtained.

  Furthermore, according to the first embodiment, since the auxiliary rhombus hair bundle 15b including the diamond-shaped cross-section bristle 14a is provided at the tip of the brush portion 16 in the longitudinal direction X, the auxiliary rhombus hair bundle 15b allows the back teeth of the back teeth. The cleaning can be performed more effectively.

  4A and 4B show a toothbrush 20 according to a second preferred embodiment of the present invention. The toothbrush 20 according to the second embodiment has substantially the same configuration as that of the toothbrush 10 of the first embodiment, while the rhombic hair bundle 15a disposed at the front end portion of the large curved recess 17b and the rear end Circular cross-section bristles 14b provided between the rhombic hair bundles 15a are arranged in two rows and six locations.

  FIGS. 5A and 5B show a toothbrush 30 according to a preferred third embodiment of the present invention. The toothbrush 30 according to the third embodiment has substantially the same configuration as that of the toothbrush 10 of the first embodiment, but the rear end of the brush part 16 is not provided with the rhombus hair bundle 15a, and the brush part. The auxiliary rhombus hair bundle 15b is provided only at the tip of 16.

  6A and 6B show a toothbrush 40 according to a fourth preferred embodiment of the present invention. The toothbrush 40 according to the fourth embodiment has substantially the same configuration as that of the toothbrush 10 of the first embodiment, while the rhombic hair bundle 15a and the large curved recess 17b arranged at the tip of the small curved recess 17a. A circular cross-section bristle 14b provided between the rhombic hair bundle 15a arranged at the front end side portion, a rhombus hair bundle 15a arranged at the front end side portion of the large curved concave portion 17b, and a rhombus hair bundle at the rear end. The circular cross-sectional bristle 14b provided so as to be interposed between 15a and 15a is arranged in two rows and six places. Moreover, the hair | bristle bundle arrange | positioned at the front-end | tip of the brush part 16 is replaced with the auxiliary rhombus hair | bristle bundle 15b, and is the circular hair | bristle bundle 15c.

  The toothbrushes 20, 30, and 40 according to the second to fourth embodiments also provide substantially the same operational effects as the toothbrush 10 of the first embodiment.

  The present invention is not limited to the configuration of each of the above embodiments, and various modifications can be made. For example, it is not always necessary to arrange a plurality of rhombic hair bundles in the width direction perpendicular to the longitudinal direction of the brush part, and the rhombic hair bundles may be arranged in a staggered manner or randomly arranged in the brush part. . Further, it is not always necessary to provide the auxiliary rhombus hair bundle at the tip in the longitudinal direction of the brush portion, and it is not always necessary to plant the rhombus hair bundle or the auxiliary rhombus hair bundle in an inclined manner.

  Hereinafter, although the toothbrush of this invention is demonstrated in detail by an Example and a comparative example, this invention is not limited to these.

[Example 1]
A toothbrush having the same configuration as that of the toothbrush 10 of the first embodiment is used as a toothbrush of Example 1, and “a plaque removing power (removing power of colored stains) with respect to a tooth smooth surface and a tooth gap” and “a feeling of use”. Was evaluated according to the method described below. The evaluation results are shown in Table 1. In addition, the bundle diameter of the rhombus hair bundle and the auxiliary rhombus hair bundle was 1.8 mm, and the hair diameter of the rhombus section bristle constituting the rhombus hair bundle or the auxiliary rhombus hair bundle was 8 mil. The rhombus hair bundle or the auxiliary rhombus hair bundle was inclined from the vertical direction at an angle of 2 degrees toward the center in the width direction or the center in the longitudinal direction. The bundle diameter of the circular hair bundle was 1.6 mm, and the hair diameter of the circular cross-section bristles constituting the circular hair bundle was 8 mil.

[Comparative Examples 1 and 2]
The toothbrush of Example 1 was used as the toothbrush of Comparative Example 1 by aligning the hair height to the highest height in the small curved concave portion or the large curved concave portion. Further, in the toothbrush of Example 1, the circular bristle bundle with the circular cross-section bristle is replaced with the hair bundle with the rhombus cross-section bristle similar to the rhombus bristle bundle and the auxiliary rhombus bristle bundle while maintaining the bundle diameter. A toothbrush was used. Regarding the toothbrushes of Comparative Example 1 and Comparative Example 2, as with the toothbrush of Example 1, “plaque removal power (removal power of colored stains) with respect to the tooth smooth surface and the tooth gap” and “use feeling” Evaluation was made according to the method described below. The evaluation results are shown in Table 1.

[Plate removal for smooth tooth surface and gap between teeth]
The clinical evaluation test was conducted according to the following procedure.
That is, three males with no dentition irregularities in the test teeth were selected as subjects, and the test teeth were polished. After complete removal of the plaque, brushing was stopped and plaque was accumulated. After 24 hours, the plaque was dyed red with a staining solution, and then brushed with each evaluation toothbrush to remove the plaque.
In addition, toothpaste was performed as follows by surgeon brushing.
Brushing method: scraping method Brushing time: 10 seconds for 2 teeth Brushing pressure: 200g
“Good plaque removal” was evaluated as “◯”, “There is plaque remaining in the interdental region” as “Δ”, and “Insufficient plaque removal” as “×”.

[Use feeling]
The above three male subjects were surveyed and evaluated for the feeling of use when brushing their teeth.
In addition, “○” indicates that the teeth and gums are soft and dirt is removed. “Yes” indicates that “the tip of the hair feels the hardness of the tips and is difficult to enter the gap”. "I can't polish because it hurts."

  According to Table 1, the toothbrush of Example 1 according to the present invention is extremely excellent in both “plaque removal power (removal power of colored stains) with respect to the smooth surface of the teeth and the gap between the teeth” and “feeling of use”. It turns out that high evaluation is obtained.

The structure of the principal part of the toothbrush which concerns on preferable 1st Embodiment of this invention is demonstrated, (a) is a top view, (b) is a side view, (c) is a front view. (A) is explanatory drawing of a rhombus cross-section bristle, (b) is explanatory drawing of a circular cross-section bristle. (A)-(c) is explanatory drawing of the condition which brushes out a tooth using the toothbrush which concerns on preferable 1st Embodiment of this invention. The structure of the principal part of the toothbrush which concerns on preferable 2nd Embodiment of this invention is demonstrated, (a) is a top view, (b) is a side view. The structure of the principal part of the toothbrush which concerns on preferable 3rd Embodiment of this invention is demonstrated, (a) is a top view, (b) is a side view. The structure of the principal part of the toothbrush which concerns on preferable 4th Embodiment of this invention is demonstrated, (a) is a top view, (b) is a side view.

Explanation of symbols

10, 20, 30, 40 Toothbrush 11 Flocking table 12 Neck part 13a First flocking hole 13b Second flocking hole 14a Rhombus cross-section bristle 14b Circular cross-section bristles 15a Rhombus hair bundle 15b Auxiliary rhombus bristles 15c Circular follicle bundle 16 Brush section 17 Waveform shape Portion 17a Small curved concave portion 17b Large curved concave portion 18a Tip apex portion 18b Intermediate apex portion 18a Rear end apex portion 19 Intermediate curved convex surface s Tip line connecting tips of hair bundles Longitudinal direction Y of brush portion Y Width direction of brush portion

Claims (9)

When the brush portion is viewed from the side, the tip line connecting the tips of the hair bundle has a sharply curved small concave portion and a large curved concave portion with a gentle curve. A toothbrush having a waveform-shaped portion that is continuously provided,
The small curved concave portion and the large curved concave portion each include a rhomboid hair bundle in which 80 to 100% of all the bristle is a diamond-shaped cross-sectional bristle, and the rhomboid hair bundle is circular in the longitudinal direction of the brush portion. Or a toothbrush planted with a bunch of hexagonal or more regular polygon cross-section bristles interposed.   The toothbrush according to claim 1, wherein the rhombic hair bundle is contained in an area ratio of 25 to 75% in the plurality of hair bundles constituting the brush portion.   The toothbrush according to claim 1 or 2, wherein a maximum curvature radius of the small curved recess is 0.5 to 2.5 mm, and a maximum curvature radius of the large curved recess is 2.6 mm or more.   The toothbrush according to any one of claims 1 to 3, wherein the small curved concave portion is disposed on a distal end side in the longitudinal direction of the brush portion, and the large curved concave portion is disposed on a rear end side in the longitudinal direction of the brush portion.   The toothbrush according to any one of claims 1 to 4, wherein a plurality of the rhombuses are arranged in a row in a width direction perpendicular to the longitudinal direction of the brush portion.   The toothbrush according to any one of claims 1 to 5, wherein the hair bundle at the most longitudinal end of the small curved concave portion is a rhombus hair bundle in which 80 to 100% of all bristle is a diamond cross-section bristle.   The toothbrush in any one of Claims 1-6 by which the auxiliary bristle bundle which consists of a rhombus cross-section bristle is provided in the front-end | tip of the longitudinal direction of the said brush part.   The rhombus hair bundle or the auxiliary rhombus hair bundle is a large-diameter hair bundle having a diameter of 1.7 to 2.5 mm, and the hair bundle composed of the other bristle is a small diameter having a diameter of 1 to 1.6 mm. The toothbrush in any one of Claims 1-7 used as the hair | bristle bundle. The rhombus hair bundle or the auxiliary rhombus hair bundle is provided to be inclined from the vertical direction at an angle of 0.5 to 5 degrees on the width direction center side or the longitudinal direction center side of the brush portion. The toothbrush in any one of 8.