New device
A toothbrush with non-tapered and chemically tapered bristles addresses the challenge of balancing cleaning effectiveness and gum gentleness, providing comprehensive plaque removal and preventing periodontal issues.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2021-12-09
- Publication Date
- 2026-03-19
Abstract
Description
Technical Field
[0001] The present invention relates to a toothbrush, and more particularly to the bristle configuration of a toothbrush head. In particular, the present invention relates to an improved toothbrush bristle configuration having different types of bristles arranged in a specific pattern.
Background Art
[0002] Toothbrushes are established devices for oral hygiene. Toothbrushes are used to clean teeth to remove debris between and on the teeth and to remove dental plaque on the tooth surfaces. Dental plaque is one of the main causes of dental problems such as tooth decay, gingivitis and periodontal diseases such as periodontitis.
[0003] Manual toothbrushes need to be moved by hand movement. Electric toothbrushes perform automatic bristle movements such as rotational vibration or reciprocating vibration. There are also semi-electric toothbrushes, which are designed like manual toothbrushes but have means for vibrating the toothbrush head.
[0004] A toothbrush head can be provided with single-structure bristles such as hard single-structure bristles or soft single-structure bristles. Other toothbrush heads can be provided with tapered bristles. Hard bristles are preferred for efficient cleaning of tooth surfaces, especially exposed tooth surfaces. However, hard bristles are not gentle on the gums and can even cause irritation or damage to the gums. Furthermore, hard bristles do not penetrate into the adjacent spaces between teeth and other hard-to-reach tooth surfaces. Soft single-structure bristles are gentler on the gums but still do not achieve sufficient cleaning and plaque removal of hard-to-reach surfaces. Tapered bristles achieve good penetration into hard-to-reach tooth surfaces. However, due to their flexibility, the brushing pressure by tapered bristles is limited. As a result, longer brushing times may be required to achieve sufficient cleaning and plaque removal.
[0005] Certain types of bristle and toothbrushes equipped with those bristle are disclosed in U.S. Patent Application Publication 2015 / 257525(AA). Disclosed are toothbrush bristles and a method for manufacturing toothbrushes using those bristles, the bristle having a core-sheath dual structure. The core and sheath are made from two separate polymer resins. The polymer resin of the sheath has a higher solubility in the tapering solution than the polymer resin of the core. When the bristle is immersed in the tapering solution, the resin of the sheath dissolves more rapidly than the resin of the core, exposing the core, and as a result, the branched end bristle is chemically tapered. By embedding those bristles into a toothbrush head, a toothbrush equipped with the bristle is produced. Branched end bristles, as disclosed in U.S. Patent Application Publication 2015 / 257525(AA), and toothbrushes made using them are not ideal for quick and effective tooth cleaning. The thin branched end may bend or break under brushing force. As a result, longer brushing times may be necessary to achieve sufficient cleaning and plaque removal. Generally, various types of bristle materials and configurations are known. Each type of bristle has specific advantages but also disadvantages. The inventors are seeking a toothbrush with a bristle configuration that balances effective and rapid cleaning of exposed tooth surfaces with gentleness to the gums. The toothbrush should also provide good penetration into interdental spaces and subgingival margins to remove plaque that causes periodontal symptoms in hard-to-reach areas. The toothbrush should also achieve good plaque removal on the interdental surfaces of teeth, the tooth surfaces near the gingival margins, and the subgingival tooth surfaces. The toothbrush should have a low risk of irritation to the gums. The toothbrush should be particularly suitable for preventing periodontal symptoms such as gingivitis and periodontal disease, such as periodontitis. The toothbrush should also be particularly suitable for situations where periodontal symptoms are already present in order to prevent further deterioration and progression of the disease and to support gum recovery. [Overview of the project] [Means for solving the problem]
[0006] definition The terms "tapered bristle" or "tapered filament" are terms used in the field of toothbrush bristles and are synonymous with "tapered bristle" or "needle-shaped bristle."
[0007] Unless otherwise specified, the length of the bristle is measured from the point where the bristle extends from the bristle surface.
[0008] The disclosure provides a toothbrush head connected to or connectable to a handle so as to define a head-handle longitudinal direction and a width direction perpendicular to the longitudinal direction, the head having a bristle surface having a distal end further from the handle and a proximal end closer to the handle, and having both ends in the width direction, from which a tufted bristle extends, the tufted bristle comprising a first tuft having a first bristle and a second tuft having a second bristle, the first bristle being a non-tapered, rounded-end bristle having a circular cross-section, the second tuft being positioned at the outermost part of the bristle surface closest to the distal end and the outermost part closest to the proximal end, and / or at the outermost part of the bristle surface closest to both ends in the width direction, the second bristle having a stem branching to a branched end, the branched end being chemically tapered.
[0009] The disclosure further provides a toothbrush head connected to or connectable to a handle so as to define a head-handle longitudinal direction and a width direction perpendicular to the longitudinal direction, the head having a bristle surface having a distal end further from the handle and a proximal end closer to the handle, and having both ends in the width direction, and a tufted bristle extending from the bristle surface, the tufted bristle comprising a first tuft having a first bristle and a second tuft having a second bristle, the second tuft being positioned on the bristle surface at the outermost point closest to the distal end or the outermost point closest to the proximal end, or at the outermost point closest to both ends in the width direction, or a combination thereof, the second bristle having a stem branching to a branched end, the branched end being chemically tapered.
[0010] In one embodiment, the second tuft consists only of the second bristle.
[0011] In one embodiment, the second tuft is positioned on the bristle surface at the outermost edge, closest to both ends in the width direction.
[0012] In one embodiment, the second tuft is positioned axially symmetric with respect to the head-handle longitudinal direction on the bristle surface.
[0013] In one embodiment, the length of the second bristle is uniform for all of the second bristle, measured from the position where the second bristle protrudes from the bristle surface.
[0014] In one embodiment, the length of the second bristle is longer than the length of any other bristle on the bristle surface.
[0015] In one embodiment, the stem of the second bristle extends over approximately 80% to 70% of the length of the second bristle, measured from the position where the second bristle protrudes from the bristle surface.
[0016] In one embodiment, the second bristle is approximately 1.5 mm to 2.5 mm longer than the longest first bristle, measured from the position where the first and second bristles protrude from the bristle surface, and the branched end is approximately 2.5 mm to 3.5 mm in length, the length of which is measured from the point where the stem of the first bristle branches into the branched end to the tip of the branched end.
[0017] In one embodiment, the stem of the second bristle branches into 2 to 20 branched ends.
[0018] In one embodiment, the stem of the second bristle branches into 2 to 8 branched ends.
[0019] In one embodiment, the stem of the second filament has a circular cross-section with a diameter of 5 to 8 mils.
[0020] In one embodiment, the first bristle has a diameter of 5 to 8 mils.
[0021] In one embodiment, the bristle surface has only a first tuft and a second tuft, and the first tuft is positioned on the bristle surface at the outermost part closest to the distal end, the outermost part closest to the proximal end, and in the center inward from both ends in the width direction.
[0022] In one embodiment, the length of the first bristle is not uniform in the concave cross section along the head-handle longitudinal direction, measured from the position where the first bristle protrudes from the bristle surface, and the length of the first bristle located closest to the distal end is the same as the length of the first bristle located closest to the proximal end.
[0023] Toothbrushes having toothbrush heads like those disclosed herein are also provided.
[0024] A method for treating gingivitis is also provided, which includes brushing teeth using the toothbrush described in this specification. A method for treating periodontal diseases, such as periodontitis, which includes brushing teeth using the toothbrush described in this specification is also provided. A method for reducing plaque on the tooth surfaces near the adjacent surfaces of teeth and the gum line, which includes brushing teeth using the toothbrush described in this specification is also provided.
[0025] a) providing a first tuft comprising a first bristle that is a single-structured bristle; b) providing a second tuft comprising a second bristle having a chemically tapered branched end; c) fixing the first tuft to the toothbrush head at the outermost part closest to the distal end, the outermost part closest to the proximal end, and at the center inside from both ends in the width direction on the bristle surface of the toothbrush head; d) cutting the first tuft so as to form a concave cut along the head-handle longitudinal direction of the toothbrush head; e) polishing the bristles of the first tuft to provide a first bristle having a single structure and a rounded end; f) fixing the second tuft to the toothbrush head at the outermost part closest to both ends in the width direction on the bristle surface; including in this order, A method for manufacturing a toothbrush is also provided, wherein after fixing the second tuft to the toothbrush head, the length (l1) of the second bristle, measured from the position where the second bristle protrudes from the bristle surface, is longer than the length of any bristle of the first tuft.
[0026] Detailed Description Definitions The term "tapered bristle" or "tapered filament" is a term for a toothbrush bristle and is synonymous with "tapering bristle" or "needle-shaped bristle".
[0027] Unless otherwise specified, the length of the bristle is measured from the point where the bristle extends from the bristle surface.
[0028] Preferably, the bristle surface is flat. The bristle that is assembled into a tuft protrudes from the bristle surface in the bristle direction. The bristle direction can be uniform for all tufted bristles or it can be different for different tufts. It is preferable that the bristle direction is uniform for all tufted bristles. The bristle direction can be perpendicular to the bristle surface. Alternatively, the bristle direction can be inclined with respect to the head-handle longitudinal or width direction for some or all of the tufted bristles. Preferably, the bristle direction of the first tuft is perpendicular to the bristle surface. Preferably, the bristle direction of the second tuft is perpendicular to the bristle surface. It is most preferable that the bristle directions of all first and second tufts are perpendicular to the bristle surface. In embodiments having a flat bristle surface, it is most preferable that all first and second tufts extend from the bristle surface in a bristle direction perpendicular to the head-handle longitudinal and width directions. In embodiments with other types of tufts, it is preferable that, in addition to the first and second tufts, all tufts on the toothbrush head extend from the bristle surface in a bristle direction perpendicular to the bristle surface.
[0029] The teachings of this disclosure are not limited to toothbrush heads having a fixed number of tufts. The teachings can be modified by those skilled in the art to create toothbrush heads of various sizes, and consequently, various numbers of tufts. In some embodiments, a toothbrush head may have 20 to 38 tufts. If it is preferable to provide a wider toothbrush head, there may typically be 30 to 26, for example, 33 tufts. If it is preferable to provide a smaller toothbrush head, there may typically be 22 to 28, for example, 25 tufts.
[0030] Additional types of tufts may exist in addition to the first and second tufts. However, it is preferable that the toothbrush head contains only the first and second tufts. The first and second tufts have different types of bristle. Therefore, the first tuft can be distinguished from the second tuft. The first tuft has a first bristle. The second tuft has a second bristle. The first and second bristles are two different types of bristles. In other words, the first bristle is not the same type of bristle as the second bristle.
[0031] Tufts can be fixed to a toothbrush head in a manner known in the art. Depending on the materials of the bristle and toothbrush head, numerous techniques are known for attaching bristle or tufted bristle to the bristle surface. For example, polymer plastic filaments can be cut, bent into a U-shape to form bristles with doubled ends, and then bundled together with small metal anchors to form a tuft. The anchors can be press-fitted into recesses provided for the tufts in the bristle surface of the toothbrush head. These recesses are often referred to as tuft holes. The toothbrush head can be injection-molded from a thermoplastic elastomer such that the tuft holes are anticipated in the bristle surface. The elasticity of the thermoplastic elastomer of the toothbrush head fixes the anchors, and therefore the tufted bristle, to the bristle surface. Preferably, the first and second tufts are embedded in the toothbrush head using metal anchoring techniques. Small metal anchors are used to bundle individual bristles within the tuft. Next, these metal anchors are inserted into tuft holes in the bristle surface. The toothbrush head is made from plastic material. The elasticity of the plastic material of the toothbrush head holds the metal anchors in place. However, it is emphasized that the specific beneficial bristle arrangements disclosed herein are not limited to any tuft forming and / or embedding method. The bristle arrangements disclosed herein can be realized by any tuft forming and / or embedding method. For example, in another well-known process, the ends of a tufted bristle can be supported so that they extend into the mold cavity in which the toothbrush head will be molded, and molten plastic material can be injected in a fluid state around the ends so that the ends are firmly embedded in the toothbrush head as the injected plastic material hardens.
[0032] The first tuft is positioned in the toothbrush head so as to reach more exposed tooth surfaces while brushing teeth. The first tuft is located in the center of the toothbrush head between the two ends in the width direction. The first tuft can be located directly on or near the axis along the head-handle longitudinal direction, or it can be located to the left and right of the axis. Preferably, the first tuft is arranged axially with respect to the axis along the head-handle longitudinal direction on the bristle surface. As previously described, the teachings of the present invention are not limited to a toothbrush of a particular size having a particular number of tufts. However, in a preferred embodiment, there can be 10 to 20 first tufts. More preferably, there can be 12 to 18 first tufts. In an embodiment having a total of 33 tufts, there are preferably 17 first tufts. In an embodiment having a total of 25 tufts, there are preferably 13 first tufts. The first tuft can typically have a generally circular cross-section, with a diameter of approximately 1 mm to 2 mm.
[0033] The first tuft comprises a first bristle. The first tuft may optionally comprise other bristles. However, it is preferable that the entire first tuft is made from the first bristle. The first bristle is a uniform bristle with rounded ends. The first bristle is made primarily from a filament of polymer plastic material. Many different types of filaments are known for toothbrush bristles. The first bristle can be made from a single polymer material filament, typically from polyamide such as Tynex (e.g., nylon such as nylon 6.12), polybutylene terephthalate (PBT), or polyethylene terephthalate (PET). Preferably, the first bristle is made from a nylon filament. Nylon bristles provide excellent brushing performance. The first bristle is generally of a uniform circular cross-section, not tapered, and with rounded ends; that is, the ends away from the bristle surface are rounded to prevent damage to oral soft tissues such as the gums. The first bristle typically has a diameter of about 5 mils (0.13 mm) to about 8 mils (0.2 mm). A diameter of about 6 mils (0.15 mm) to about 7 mils (0.18 mm) is most preferred. Its strength provides good resilience to the bristle, making it gentle on the gums. At the same time, its strength also ensures satisfactory cleaning and plaque removal. The toothbrush heads and toothbrushes described herein achieve good cleaning, especially of exposed or easily accessible tooth surfaces, by the first tuft of the first bristle. Thus, in one embodiment, the first bristle is a uniform, rounded-end nylon bristle with a diameter of about 5 mils (0.13 mm) to about 8 mils (0.2 mm).
[0034] The first tufts can all be the same length. Preferably, the first tufts have non-uniform lengths. Preferably, the first tufts are cut to form a concave cut along the head-handle longitudinal direction. Thus, the ends of the first bristle of the first tuft form a ridged bristle profile between the distal and proximal ends of the toothbrush head. In one embodiment, the length of the first bristle is non-uniform in the concave cut along the head-handle longitudinal direction, measured from the position where the first bristle protrudes from the bristle surface, and the length of the first bristle located closest to the distal end is the same as the length of the first bristle located closest to the proximal end. The longest first bristle length can be about 8 mm to about 12 mm. The shortest first bristle length can be about 10 mm to about 6 mm. Preferably, the longest first bristle is about 9 mm to about 11 mm in length, and the shortest first bristle is about 2 mm shorter than the longest first bristle. In one embodiment, the lengths of the first bristle differ by about 2 mm at the concave cut along the head-handle longitudinal direction, measured from the position where the first bristle protrudes from the bristle surface. The longest first bristle is positioned at the outermost edge closest to the distal end of the toothbrush head and the outermost edge closest to the proximal end. The concave cut of the first bristle ensures good contact between the first bristle and the tooth surface. This provides better brushing performance. In the toothbrush disclosed herein, the first bristle provides good brushing performance of the exposed tooth surface and sufficient cleaning of easily accessible areas. On the other hand, the second bristle enables good access to hard-to-reach areas, namely the gingival line and subgingival margin.
[0035] By providing a first bristle with a concave cutout along the longitudinal direction of the head-handle, the first bristle remains in direct contact with the tooth surface for a longer period of time during brushing. The concave cutout resembles the natural curvature of the dentition. As a result, the first bristle remains in contact with the tooth surface for a longer period of time during brushing, even without special brushing techniques. Thus, a good surface cleaning effect can be achieved. Importantly, this cleaning effect can be achieved without the need for harder bristles. In the art, harder bristles are usually selected to achieve a better cleaning effect on exposed tooth surfaces. However, as discussed earlier in the background art section, hard bristles can cause irritation to the gums. This problem is overcome by providing the first bristle with a concave cutout along the longitudinal direction of the head-handle, as described above. Thus, a softer first bristle can be used to provide a softer and more gum-friendly toothbrush.
[0036] In a preferred embodiment, there can be 4 to 20 second tufts. More preferably, there can be 10 to 18 second tufts. In an embodiment with a total of 33 tufts, preferably, there can be 16 second tufts. In an embodiment with a total of 25 tufts, preferably, there can be 12 second tufts. The second tufts are positioned on the toothbrush head so that they can reach the gingival margin and subgingival margin while brushing the teeth. In this way, the second bristle provides superior cleaning of the gingival margin and subgingival region of the teeth, complementing the cleaning effect of the first bristle of the first tuft. In a preferred embodiment, the second tufts are positioned at the outermost edges closest to both ends in the width direction. In one embodiment, the second tufts are positioned at the outermost edges closest to the proximal and distal ends. In yet another preferred embodiment, the second tuft is positioned at the outermost edges closest to both ends in the width direction and at the outermost edges closest to the proximal and distal ends, in other words, around the periphery of the bristle surface. In one embodiment, the second tuft is positioned at the edge of the toothbrush head. By positioning it at the outer edge of the bristle surface, the second bristle of the second tuft achieves excellent reach to the gingival margin and the interdental spaces between teeth. Preferably, in one embodiment, the second tuft is positioned axially symmetric with respect to an axis along the head-handle longitudinal direction on the bristle surface. Preferably, the second tuft is positioned to be the second tuft of two lines tangent to both ends and the boundary in the width direction of the toothbrush head. The second tuft can typically have a generally circular cross-section with a diameter of about 1 mm to about 2 mm.
[0037] The second tuft comprises a second bristle. The second tuft may additionally comprise other bristles. However, it is preferable that the second tuft is entirely made from the second bristle. The second bristle has a furcation end. The furcation end is chemically tapered. Thus, the second bristle can be called a bristle with a tapered furcation end. Thin bristles are beneficial for penetration into interdental spaces and subgingival margins, but thin, single-structure bristles have a lower limit of thickness due to constraints on manufacturing, tuft formation, and durability. In contrast, furcation end bristles can have a stem that is appropriately thick for good tuft formation and durability, while preferably having a thin free end. The furcation end is flexible and soft, which is desirable for sensitive gingiva or periodontal conditions. Chemical tapering of the bristle prevents sagging, uneven furcation, and wear. Chemical tapering allows for the creation of extremely fine, thin ends, which cannot be achieved by other techniques. Preferably, the second bristle is chemically treated to achieve stem branching and tapering for branched ends. Preferably, chemical branching is achieved by chemical treatment of the composite filament, and the polymer used in the composite filament has a specific solubility in the tapering solution. The tapering solution can be an acid or a lake. Chemical branching is preferred over mechanical filament branching techniques such as cutting or extrusion using a blade. Mechanically branched bristle may have uneven ends, drooping ends, wear and abrasion of fine plastic particles, and a rough bristle surface with a risk of microbial growth. Furthermore, such chemical branching techniques produce branched and tapered bristle in a single manufacturing step. In one embodiment, the second bristle is a chemically branched, chemically tapered, branched end bristle.
[0038] The second bristle has a stem that branches at the branched end. The stem can branch into 2 to 20 branched ends. Preferably, the stem branches into 2 to 8 branched ends. It is most preferable that the stem branches into 4 branched ends. In a preferred embodiment, the stem has a strength of about 5 mil (0.13 mm) to about 8 mil (0.2 mm). More preferably, the stem has a strength of about 7 mil (0.18 mm) to about 8 mil (0.2 mm). The branched ends are chemically tapered.
[0039] In one embodiment, the stem of the second bristle extends over 99% to 50% of the length (l1) of the second bristle, measured from the position where the second bristle protrudes from the bristle surface. In one embodiment, the stem of the second bristle extends over 60% to 80% of the length of the second bristle, measured from the position where the second bristle protrudes from the bristle surface. In one embodiment, the stem of the second bristle extends over approximately 75% of the length of the second bristle, measured from the position where the second bristle protrudes from the bristle surface. In one embodiment, the second bristle is branched for approximately 20% to 30% of its length, and its length is measured from the position where the second bristle protrudes from the bristle surface. In one embodiment, the second bristle is branched for approximately 25% of its length, and its length is measured from the position where the second bristle protrudes from the bristle surface.
[0040] In one embodiment, the furcation end is approximately 2.5 mm to 3.5 mm in length. In another embodiment, the furcation end is approximately 2.7 mm to 3.2 mm in length. In yet another embodiment, the furcation end is approximately 3 mm in length. The length of the furcation end is measured from the point where the stem of the first bristle branches into the furcation end to the tip or tip of the furcation end. The described second bristle structure provides very fine furcation ends, which are excellent at reaching hard-to-reach tooth areas such as the gingival margin and subgingival margin. Chemically tapered furcation ends provide good reach or penetration into narrow areas. The length and thickness of the furcation end make the second bristle flexible without bending or excessive wear, and therefore gentle on the gingiva. Combined with the features of the first tuft of the first bristle, a balance is found between flexibility and cleaning effectiveness.
[0041] The second bristle can be made from polybutylene terephthalate (PBT). The branched ends are chemically treated to achieve tapering. Therefore, preferably, the second bristle has substantially the same shape, thickness, and tapered branched ends. In other words, preferably, the second bristle has uniformly formed tapered branched ends. Uniformity of the branched ends has an additional positive effect on the cleaning effectiveness of the toothbrush, as all branched ends have the same elasticity and therefore have uniform brushing resistance. This is also preferable because all branched ends wear uniformly. The branched ends preferably have a smooth surface. This is preferable because depressions and irregularities on the surface of the branched ends can become breeding grounds for bacteria. Furthermore, irregularities can cause breakage and shedding of microplastic particles, which may be swallowed or eventually enter the wastewater. Therefore, the toothbrush disclosed herein reduces the shedding of microplastic particles. For example, the second Bristle can be purchased from BBC (Best Bristle Company Co., Ltd., 210 Daedeok-daero 1448beon-gil, Dadeok-gu, Dajeon 34324, South Korea).
[0042] Tufts made from the second bristle are very gentle on the gingiva and gums. Furthermore, they achieve very good penetration and plaque removal in the adjacent space and subgingival region. The second tuft may have an uneven length; however, it is preferable that the second tuft has a uniform length. It is preferable that the second tuft is longer than the first tuft. Preferably, the second tuft is the longest in the bristle surface. In such a configuration, the branched end of the second bristle protrudes beyond any other bristle in the bristle surface. The length of the second bristle can be about 10 mm to about 14 mm. Preferably, the second bristle is about 11 mm to about 13 mm in length. Preferably, the second bristle is about 1.5 mm to about 2.5 mm longer than the longest first bristle. In this way, the second bristle can reach the interdental space and gingival margin while the first bristle is in contact with a more accessible or exposed tooth surface. In one embodiment, the second bristle is about 1.5 mm to 2.5 mm longer than the longest first bristle, measured from the position where the first and second bristles protrude from the bristle surface, with the bifurcation end being about 2.5 mm to 3.5 mm in length, the length of which is measured from the point where the stem of the first bristle bifurcates to the bifurcation end to the tip of the bifurcation end. Thus, the second bristle not only bifurcates in the length beyond the first bristle, but also in the length where it overlaps with the first bristle. In this way, better reach of the bifurcation end of the second bristle can be achieved. When brushing, the first bristle can be in contact with an easily accessible tooth surface, and the second bristle, which is longer than the first bristle, bends to reach the gingival margin. The bifurcation end is softer and more flexible when it is longer than the difference in length between the first and second bristle. This allows for better access to the gingival line and subgingival margin, and therefore cleaning, while also enabling a gentler approach to the gingiva.
[0043] The specific arrangement and combination of the first and second tufts in the toothbrush head, as disclosed, achieves an optimal balance between brushing performance and flexibility or gentleness. Additionally, by adjusting the lengths of the first and second tufts as described, optimal reach to the interdental spaces and gingival margins is achieved. This is particularly useful because plaque, a major cause of periodontal symptoms, tends to accumulate particularly in these tooth surface areas. Therefore, the toothbrush disclosed herein is particularly suitable for preventing and / or treating periodontal disease and periodontal symptoms.
[0044] The toothbrush head may optionally further comprise a tongue cleaner. The tongue cleaner can be realized on the side of the toothbrush head opposite the bristle surface and can be fabricated from a thermoplastic elastomer by injection molding. The tongue cleaner is particularly suitable for use in combination with the bristle arrangement of the present invention because it is efficient in removing bacteria from the tongue. The toothbrush heads disclosed herein, further comprising a tongue cleaner, are particularly suitable for preventing and alleviating gingival problems and periodontal disease.
[0045] The toothbrush head may also optionally be equipped with an impact protector. The impact protector can cover each portion of the outer surface of the toothbrush head and can cushion any impact the toothbrush head may have on the teeth and gums when brushing vigorously. In addition, it provides the toothbrush head with a soft and comfortable feel in the mouth. The impact protector can be manufactured from a thermoplastic elastomer by injection molding. Preferably, the impact protector covers the lateral edges of the toothbrush head. Optionally, in embodiments without a tongue cleaner, the impact protector also covers the surface of the toothbrush head opposite the bristle surface. Embodiments equipped with such an impact protector further reduce the risk of damaging the gums, thereby making those embodiments particularly suitable for combination with the bristle arrangements disclosed herein.
[0046] toothbrush The toothbrush heads of the present disclosure can be manual toothbrushes, i.e., toothbrush heads in contact with the user's teeth that are moved solely by the movement of the hand, or electric toothbrush heads located on the handles, where the head is moved by an electric, for example, battery-operated motor. In the case of electric toothbrushes, the toothbrush heads of the present invention can be permanently connected to or replaceably connected to a toothbrush handle housing a drive motor by means of means well known in the toothbrush field, for example, means adapted to move the toothbrush head to perform a bath-type motion under the operation of a drive motor.
[0047] This disclosure further provides a toothbrush having a toothbrush head as disclosed herein. The toothbrush head may be connected to or be connectable to a handle. The handle may have an ergonomic gripping portion. The ergonomic gripping portion facilitates grasping and holding the toothbrush with one hand and guides the brushing movement of the toothbrush head in the mouth while brushing. The connection portion between the handle and the toothbrush head is often referred to as the neck or neck area. The toothbrush described herein may optionally be equipped with a handle attachment to reduce excessive brushing force. An example of such a handle attachment is a flexible link in the neck area. The handle attachment can alleviate excessive pressure that the user may apply to the teeth by bending the handle attachment. In doing so, the risk of gingival damage due to excessive brushing force is reduced. The flexible link increases the degree of flexibility between the head and the neck area. Such a flexible link is preferably comprised of a thin portion integrated with the neck region, which is thinner in the transverse and / or width directions relative to the portion immediately adjacent to the neck region in the longitudinal direction, or to the portion immediately adjacent to the neck region and the toothbrush head in the longitudinal direction. Alternatively, the flexible link may be located between the neck region and the toothbrush head.
[0048] The flexible link is preferably comprised of a portion integrated with the neck region and the toothbrush head, which is thinner in the transverse and / or widthwise direction relative to the portion immediately adjacent to the neck region and the toothbrush head in the longitudinal direction.
[0049] Preferably, the thin portion is in the form of a spine made of a plastic material that extends longitudinally, with a longitudinal dimension of about 1 mm to about 2 mm, a width dimension of about 2 mm to about 3 mm, and a transverse dimension of about 1.5 mm to about 2.5 mm. The longitudinal cross-section of such a spine is preferably circular or oval. In a preferred embodiment, all surfaces of such a spine, facing transversely and widthwise, are surrounded by a thermoplastic elastomer material, which is preferably spherical in shape, with a diameter of about 6 mm to about 7 mm. These embodiments of the flexible link may be referred to as ball joints.
[0050] method Manufacturing method The method for manufacturing a toothbrush disclosed herein is: a) A step of preparing a first tuft having a first bristle which is a single-structure bristle, b) A step of preparing a second tuft having a second bristle having a chemically tapered branched end, c) A step of fixing a first tuft to the toothbrush head at the outermost edge closest to the distal end and the outermost edge closest to the proximal end, as well as at the center inward from both ends in the width direction, on the bristle surface of the toothbrush head, d) A step of cutting the first tuft so that it forms a concave cut along the longitudinal direction of the toothbrush head and handle, e) The step of polishing the bristle of the first tuft to provide a first bristle that is a single structure and has rounded ends, f) A step of fixing the second tuft to the toothbrush head at the outermost point closest to both ends in the width direction on the bristle surface, This includes in this order, After the second tuft is attached to the toothbrush head, the length of the second bristle (l1), measured from the point where the second bristle protrudes from the bristle surface, is longer than the length of any of the bristle lengths of the first tuft.
[0051] In one embodiment, the method includes the step of preparing a second tuft having a second bristle that is branched for about 20% to about 30% of its length, the length of which is measured from the position where the second bristle protrudes from the bristle surface after the toothbrush head has been fixed in place.
[0052] In one embodiment, the method includes the step of preparing a second tuft having a second bristle, the second bristle being about 1.5 mm to about 2.5 mm longer than the longest first bristle, the length of which is measured from the point where the first and second bristles protrude from the bristle surface, and the branched end of the second bristle being about 2.5 mm to about 3.5 mm in length, the length of which is measured from the point where the stem of the first bristle branches into the branched end to the tip of the branched end.
[0053] The method described enables the economical manufacture of toothbrushes that have both a tapered bristle with a branched end and a single-structure bristle with a desired cut length, all on the same toothbrush head. Previously known methods are more cumbersome and limited, as they usually require a mechanical branching step. Mechanical branching is undesirable due to the resulting uneven branching, as described earlier in the section on the second bristle. Additionally, during the mechanical branching step, the second bristle must be separated from the single-structure bristle with a separator. Furthermore, mechanically branched bristle cannot be tapered afterward. Also, in previously used methods, branching was performed after both types of bristle were fixed to the toothbrush head, so the length of the branched end was limited to the height difference between the branched bristle and the single-structure bristle.
[0054] Brushing teeth with the toothbrush described herein reduces plaque. As previously described, the toothbrush heads and toothbrushes described herein achieve particularly good plaque removal from hard-to-reach tooth surfaces. In particular, they can remove plaque from the interproximal surfaces of teeth and plaque from the surfaces near the gingival line of teeth. Thus, a method is provided for reducing plaque from the interproximal surfaces and tooth surfaces near the gingival line, including brushing teeth with a toothbrush such as the one described herein. In some embodiments, the method may include brushing teeth twice a day with the toothbrush described herein. In some embodiments, the method may include brushing teeth twice a day by a rotational brushing motion with the manual toothbrush described herein.
[0055] Methods for preventing periodontal symptoms are also provided, including brushing teeth using a toothbrush as described herein. In some embodiments, the method may include brushing teeth twice a day using a toothbrush as described herein. In some embodiments, the method may include brushing teeth twice a day by a rotational brushing motion using a manual toothbrush as described herein.
[0056] Methods for preventing the worsening of periodontal symptoms and the progression of disease, as well as methods for supporting the restoration of gums, are also provided. Periodontal symptoms include, for example, gingivitis and periodontal disease, such as periodontitis.
[0057] Since plaque, particularly plaque near the gingival margin, can cause and / or worsen periodontal diseases such as gingivitis and periodontitis, this disclosure also provides methods for treating these conditions. Accordingly, a method for treating gingivitis is disclosed, comprising brushing teeth using the toothbrush described herein. A method for treating periodontal disease, such as periodontitis, is also disclosed, comprising brushing teeth using the toothbrush described herein. In some embodiments, the method may include brushing teeth twice a day using the toothbrush described herein. In some embodiments, the method may include brushing teeth twice a day by a rotational brushing motion using the manual toothbrush described herein.
[0058] Here, the present invention will be described as merely an example, with reference to the attached drawings. [Brief explanation of the drawing]
[0059] [Figure 1] A top view of the toothbrush head in this disclosure. [Figure 2] Figure 1 is a vertical cross-sectional view of a toothbrush head, with the cross-section aligned along the longitudinal direction of the head-handle. [Figure 3] Side view of a toothbrush equipped with the toothbrush head shown in Figure 1. [Figure 4] Figure 1 shows a top perspective view of the toothbrush head and neck. [Figure 5] A diagram showing the first bristle extending from the bristle surface. [Figure 6] A diagram showing a second bristle extending from the bristle surface. [Modes for carrying out the invention]
[0060] Figure 1 shows a top view of the toothbrush head (1) of the present disclosure. The toothbrush head (1) is an oval-shaped plate, with a length of approximately 23 mm in the head-to-handle longitudinal direction (LL) and a width of approximately 10 mm in the width direction (WW). Starting from the left in Figure 1 along the head-to-handle longitudinal direction (LL), the toothbrush head (1) has a blunt, rounded end, then widens into an oval shape, and finally terminates with another rounded end. This end seamlessly joins to the toothbrush neck. Both parts, namely the head and the neck, are manufactured from polypropylene in a single molding process. The neck, (as can be seen in Figure 3) can seamlessly join itself to the handle (2), and is also made of polypropylene. The toothbrush head (1) has a top surface, also called the bristle surface (3), and a bottom surface opposite the bristle surface (3) (the bottom surface is not shown in the figure). The bristle surface (3) is a flat horizontal surface. The bristle surface (3) has 33 recesses, also called tuft holes, into which tuft-shaped bristle is embedded. The tufts are embedded using metal anchoring techniques known in the field of toothbrush technology. The tuft holes have a diameter of approximately 1.7 mm. The bristle surface (3) has a distal end (3A) along the head-handle longitudinal direction (LL), which is further from the handle and closer to the rounded end of the toothbrush head; a proximal end (3B) along the head-handle longitudinal direction (LL), which is closer to the handle (2) and at the end of the toothbrush head (1) opposite the proximal end (3A), and closest to the toothbrush neck; and both ends in the width direction (3C, 3D). The right side (3C) follows the right edge of the bristle surface when viewed from above, and the left side (3D) follows the left edge of the brush surface when viewed from above. The toothbrush head (1) comprises two different types of tufts, a first tuft (5) and a second tuft (7). The first tuft (5) is made from a first bristle (6). The first bristle (6) is a single-structure bristle with rounded ends. In Figure 1, the first tuft (5) is shown as a blank circle. The first bristle (6) is made from a nylon filament with a diameter of approximately 6 mils. When the first tuft (5) fills the tuft hole, its diameter is approximately 1.7 mm.The first tuft (5), when cut to a concave shape as described in detail in Figure 2, extends approximately 8 mm to 10 mm from the bristle surface (3). The first tuft (5) is located in the center of the toothbrush surface (3) between the widthwise ends (3C, 3D) of the bristle surface (3), at the distal end (3A), and at the proximal end (3B) of the bristle surface (3). The second tuft (7) is made from the second bristle (8), which is a chemically tapered bristle with a branched end. In Figure 1, the second tuft (7) is shown as a circle with a dot in the middle. The second bristle (8) is made from a polybutylene terephthalate filament. The second bristle (8) is described in more detail in the description of Figure 6. The second tuft (7) has the same diameter as the first tuft (5). The second tuft (7) extends approximately 12 mm from the bristle surface. The second tuft (7) is located at the edge of the bristle surface (3). Specifically, the second tuft (7) is positioned on the bristle surface (3) at the outermost edges closest to both ends (3C, 3D) in the width direction. In the embodiment shown in the figure, the first tuft (5) consists only of the first bristle (6), and the second tuft (7) consists only of the second bristle (8). In the embodiment shown in the figure, there are no tufts other than the first and second tufts (5, 7).
[0061] Figure 2 shows a vertical cross-sectional view of the toothbrush head (1) of Figure 1, where the cross-section passes through the center between the two ends (3C, 3D) in the width direction along the longitudinal direction (LL) of the head-handle. The body of the toothbrush head is shown with diagonal lines. As can be seen in this figure, the first tuft (5) is positioned along the cutting line. In Figure 2, the first tuft (5) is shown as a rod with a chamfered free end. This is a simplified diagram, and in reality, the first tuft (5) is not monolithic but consists of the first bristle (6) as described earlier. The chamfered free end of the first tuft (5) is shown to be cut to form a concave cut. The longest bristle of the first tuft (5) is located on the outermost part, closest to the distal end (3A) and proximal end (3B), and has a length l2 of approximately 10 mm. The shortest bristle of the first tuft (5) is centrally located along the head-to-handle longitudinal direction (LL) and has a length l3 of approximately 8 mm. In Figure 2, the second tuft (7) is mostly hidden behind the first tuft (5), with only the end of the second tuft (7) protruding upwards from behind the first tuft (5). The end of the second tuft (7) is shown in Figure 2 as a pointed tip. It should be understood that this does not mean that the second tuft (7) is monolithic or that it is a tuft cut to have a pointed profile, as the figure is simplified. In fact, as explained earlier, the second tuft (7) is a tuft made up of the second bristle (8), and they all have the same length l1. The length (l1) of the second tuft is longer than l2 and longer than l3. Both the first and second tufts extend from the bristle surface in the bristle direction perpendicular to the bristle surface (3), that is, in the bristle direction perpendicular to the width direction between the head-handle longitudinal direction (LL) and the ends (3C, 3D) in the width direction.
[0062] Figure 3 shows a side view of a toothbrush with the toothbrush head of Figure 1. As shown in Figure 2, the first tuft (5) is shown as a chamfered rod, and the second tuft (7) is shown as a tapered rod. In this figure, it can be seen that all the second tufts (7) are of the same length (l1), the first tufts (5) are cut to have a concave cut along the head-handle longitudinal direction (LL), and the second tufts (7) are longer than all the first tufts (5), and therefore protrude even beyond the longest bristle of the first tufts (5). In the embodiment shown in Figure 3, the toothbrush head (2) is made from two materials, namely polypropylene and thermoplastic elastomer. The thermoplastic elastomer is used to create an impact protection element (16) that covers the bottom surface as well as the distal end and sides of the toothbrush head. The impact protection element (16) is shown only in this Figure 3. Because it is made from thermoplastic elastomer, it cushions the impact of the toothbrush on the teeth and gums that may occur when brushing vigorously, giving the toothbrush head a soft and comfortable feel in the mouth. Figure 3 also shows that the toothbrush head (1) is integrally molded with the toothbrush handle (2). A neck (14) is formed between the head (1) and the handle (2). The handle (2) is relative to the axis of the head (1) and the neck (14) to form a handle-neck angle (α). The handle-neck angle (α) is approximately 7°. A ledge (17) is formed where the handle (2) joins the neck (14). The ledge (17) is an ergonomic aid to improve grip. Typically, the user holds the handle (2) with one hand, so that the thumb-facing side of the index finger rests on this ledge (17). When brushing, this helps to build the appropriate brushing pressure and provides a good grip on the handle (2). Additionally, a ball joint (15) is formed on the neck (14). The ball joint (15) reduces the risk of damage to the teeth or gums due to excessive brushing pressure.
[0063] Figure 4 shows a top perspective view of the toothbrush head and neck, which have the toothbrush head of Figure 1. In Figure 4, the first tuft (5) is schematically shown as a column with a chamfered, non-sharp end, and the second tuft (7) is shown as a column with a pointed end. The figure shows the first and second tufts (5, 7) extending a specific length from the bristle surface (3), with their free ends forming a bristle profile. The bristle profile of the toothbrush head is not flat, but is non-uniform due to the concave cross-section of the first tuft (5) undulating between l3 and l2, the length l1 of the second tuft, and the specific arrangement of the first and second tufts (5, 7) on the bristle surface (3). It can also be seen that the ball joint (15) is spherical and wrapped around the neck (14). The ball joint is made from thermoplastic elastomer and surrounds the narrowed portion of the neck (14).
[0064] Figure 5 shows individual first bristle (6) extending from the bristle surface (3). The first bristle (6) is a single-structure bristle with rounded ends. The first tuft (5) is entirely made from its first bristle (6). The first bristle (6) is made from a single-structure nylon filament with a thickness of approximately 6 mils. The first bristle (6) is made from those filaments known in the art, and the first tuft (5) is made from those first bristle (6), and is embedded in the bristle surface (3) using metal anchoring techniques known in the art.
[0065] Figure 6 shows a second bristle (8) extending from the bristle surface (3). The second bristle (8) is a chemically tapered, branched bristle. The second tuft (7) is entirely made from the second bristle (8). Tuft formation and embedding in the bristle surface (3) are performed using metal anchoring techniques known in the art. The second bristle (8) is made from a composite filament mainly containing polybutylene terephthalate. The second bristle (8) has a stem (19) that branches into four branched ends (21). Each branched end (21) is chemically tapered toward a single point. The length of the second bristle (8) is approximately 12 mm, measured from the point where the second bristle (8) extends from the bristle surface (3). The stem (19) has a diameter of approximately 7 mils. Since the stem (19) divides into four branched ends (21), the diameter of the branched ends (21) at their widest point, i.e., where they emerge from the stem (19), is about one-quarter the thickness of the stem (19), and therefore about 1.75 mils. The branched ends (21) are tapered from there toward a narrow, pointed end. All the branched ends (21) are of equal length. Thus, the second bristle (8) and consequently the second tuft (7) are all of the same length, about 12 mm.
[0066] [Examples] A manual toothbrush of the present disclosure, equipped with a toothbrush head having the exemplified bristle arrangement, was evaluated from the viewpoint of plaque removal effectiveness (Example 1) and gingival margin cleaning (Example 2).
[0067] [Example 1] The test was a clinically implemented brushing robot test using human teeth as a model. The effectiveness of plaque removal was evaluated using an automated planimetrical plaque assessment that analyzed 30 areas per tooth. Thus, artificial plaque was attached to human tooth models, and predetermined robotic brushing was performed at anatomical positions. The reduction of deposits from 30 predetermined areas on each tooth surface was evaluated using an automated optical method. Particular emphasis was placed on the "high-risk" areas of the teeth, namely the root surface or root region, the area just above the root surface and near the gingival line, especially the adjacent areas. These areas are difficult to remove dental plaque from and are most relevant to the prevention and reduction of periodontal disease. The toothbrush according to the present invention, shown in Figure 3, was compared to a control toothbrush without a handle, equipped with a 6-mil diameter nylon bristle with rounded ends. The size, shape, and arrangement of the tuft holes with 33 tufts of the control toothbrush head were similar to those of the toothbrush according to the present invention. Brushing was performed with a brushing force of 2.5N, which corresponds to a weak brushing force. Three tests were conducted: horizontal brushing, rotational brushing, and vertical brushing, with each movement repeated seven times.
[0068] Experiments demonstrated that the toothbrush of the present invention achieved a higher overall plaque removal rate than the control toothbrush in all three brushing motions across all 30 measured areas. The same was found when examining the "high-risk" areas individually, namely the root surface and the area just above the root surface near the gingival line. The difference in plaque removal from the area near the gingival line was more pronounced on the buccal side than on the lingual side. Therefore, the toothbrush with the bristle configuration of the present invention is optimal for plaque control in all risk areas and contributes to the prevention of caries and gingivitis.
[0069] [Example 2] In Example 2, the ability of a toothbrush bristle to remove plaque from the gingival margin around a molar shape was assessed using a pressure-sensitive substrate covered with artificial plaque. This plaque removal process is referred to in the art as gingival margin cleaning (GMC). Simulated gingiva, positioned on a simulated molar, was prepared from self-curing dental acrylic resin. The anatomical structure of the margin was fabricated using typical dental guidelines. The gap between the acrylic resin gingiva and the simulated tooth was 0.2 mm. The artificial plaque pressure-sensitive substrate was placed subgingivally and around the molar-shaped tooth, and room temperature tap water was added for 15 seconds before brushing began. Water was continuously sprayed onto the brush head and plaque substrate during brushing. The brushing technique used was a lateral brushing motion. The tested toothbrush was aligned with the papilla of the gingival margin. The brushing device was set to position the bristle at a 90° angle to the tooth surface and brush at 2 strokes per second for 15 seconds with a stroke length of 15 mm and a brushing load of 250 g. In gingival margin cleaning (GMC), the length of artificial plaque removed at the junction of the simulated gingival margin was recorded. The readings were measured in millimeters at a 3x magnification. The toothbrushes tested were visually inspected for bristle integrity before and after the completion of each brushing cycle. Descriptive statistics (mean and standard deviation) were calculated for the tested products. Analysis of variance (ANOVA) showed at least one significant difference in mean GMC values between toothbrushes. Post-hoc Tukey tests for paired comparisons identified specific significant differences in mean GMC using a significance level of 0.05. The experiment demonstrated that the toothbrush according to the present invention, as shown in Figure 3, achieved a significantly higher GMC value (average: 7.15 mm, SD: 2.96) than the control toothbrush of Example 1 (average: 3.25, SD: 1.97).
Claims
1. A toothbrush head (1) is connected to or can be connected to a handle (2) such that it defines the longitudinal direction (LL) of the head-handle and the width direction (WW) perpendicular to the longitudinal direction (LL), The head (1) has a bristle surface (3), The bristle surface (3) has a distal end (3A) further from the handle (2) and a proximal end (3B) closer to the handle (2), and also has both ends (3C, 3D) in the width direction. A tufted bristle extends from the bristle surface (3), and the tufted bristle comprises a first tuft (5) having a first bristle (6) and a second tuft (7) having a second bristle (8). The first tuft (5) is positioned on the bristle surface (3) at the outermost point closest to the distal end (3A) and the outermost point closest to the proximal end (3B), and in the center inward from both ends (3C, 3D) in the width direction. The first bristle (6) is a bristle having a circular cross-section, which is not tapered and has rounded ends. The second tuft (7) is positioned on the edge of the bristle surface (3), excluding the portion of the bristle surface (3) where the first tuft (5) is positioned, and the edge of the bristle surface (3) includes the outermost part closest to both ends (3C, 3D) in the width direction. The second bristle (8) has a stem (19) that branches to a branched end (21), and the branched end (21) is chemically tapered. The first tuft (5) and the second tuft (7) have the same diameter. The length of the first bristle (6) is not uniform in the concave cross section along the head-handle longitudinal direction (LL) when measured from the position where the first bristle (6) protrudes from the bristle surface (3), and the length (l2) of the first bristle (6) located closest to the distal end (3A) is the same as the length (l2) of the first bristle (6) located closest to the proximal end (3B), and is longer than the length (l3) of the first bristle (6) located in the center in the head-handle longitudinal direction (LL). The length (l1) of the second bristle (8) is uniform for all of the second bristle (8), measured from the position where the second bristle (8) protrudes from the bristle surface (3), and is longer than the lengths (l2, l3) of any other first bristle (6) on the bristle surface (3). The length of the branched end (21) is measured from the point where the stem (19) of the second bristle (8) branches off to the branched end (21) to the tip of the branched end (21), and is longer than the difference in length between the first bristle (6) and the second bristle (8). Toothbrush head (1).
2. The toothbrush head (1) according to claim 1, wherein the second tuft (7) consists solely of the second bristle (8).
3. The toothbrush head (1) according to claim 1, wherein the second tuft (7) is positioned on the bristle surface (3) so as to be axially symmetric with respect to the head-handle longitudinal direction (LL).
4. The stem (19) of the second bristle (8) is measured from the position where the second bristle (8) protrudes from the bristle surface (3) and is the length (l 1 The toothbrush head (1) according to claim 1, extending over 70% to 80% of the toothbrush head.
5. The toothbrush head (1) according to claim 1, wherein the second bristle is 1.5 mm to 2.5 mm longer than the longest first bristle, measured from the position where the first and second bristles protrude from the bristle surface, and the branched end is 2.5 mm to 3.5 mm in length, the length of which is measured from the point where the stem of the first bristle branches into the branched end to the tip of the branched end.
6. The toothbrush head (1) according to claim 1, wherein the stem (19) of the second bristle (8) branches into 2 to 20 branched ends (21).
7. The toothbrush head (1) according to claim 6, wherein the stem (19) of the second bristle (8) branches into 2 to 8 branched ends (21).
8. The toothbrush head (1) according to claim 1, wherein the stem (19) of the second bristle (8) has a circular cross-section, and the diameter of the circular cross-section is 5 mils to 8 mils.
9. The toothbrush head (1) according to claim 1, wherein the diameter of the first bristle (6) is 5 mil to 8 mil.
10. A toothbrush comprising a toothbrush head (1) according to any one of claims 1 to 9.
11. a) A step of preparing a first tuft having a first bristle which is a single-structure bristle, b) A step of preparing a second tuft having a second bristle with a chemically tapered branched end and having the same diameter as the first tuft, c) The step of fixing the first tuft to the toothbrush head at the outermost edge closest to the distal end and the outermost edge closest to the proximal end, and at the center inward from both ends in the width direction, d) The step of cutting the first tuft so that it forms a concave cut along the head-handle longitudinal direction of the toothbrush head, e) The step of polishing the bristle of the first tuft to provide a first bristle that is a single structure and has rounded ends, f) The step of fixing the second tuft to the toothbrush head at the edge of the bristle surface, excluding the portion where the first tuft is positioned, and including the outermost part closest to both ends in the width direction; This includes in this order, After fixing the second tuft to the toothbrush head, the length of the second bristle (l 1 The length of the first bristle (6) is uniform for all of the second bristle when measured from the position where the second bristle protrudes from the bristle surface, and is longer than the length of any of the bristle of the first tuft, and the length of the first bristle (6) is not uniform in the concave cut along the head-handle longitudinal direction (LL) when measured from the position where the first bristle (6) protrudes from the bristle surface (3), and the length of the first bristle (6) located closest to the distal end (3A) (l²) is the same as the length of the first bristle (6) located closest to the proximal end (3B), and the length of the first bristle (6) located centrally in the head-handle longitudinal direction (LL) (l³) A method for manufacturing a toothbrush in which the length of the branched end (21) is longer than the length of the first bristle (6) and the second bristle (8), and the length of the branched end (21) is measured from the point where the stem (19) of the second bristle (8) branches to the branched end (21) to the tip of the branched end (21), and is longer than the difference in length between the first bristle (6) and the second bristle (8).