Head for an oral care implement and oral care implement

Abstract

A head for an oral care implement is provided having an outer periphery and an inner portion and including at least one first type of tooth cleaning element and at least one second type of tooth cleaning element. The at least one first type of tooth cleaning element is arranged at the inner portion of the head and the at least one second type of tooth cleaning element is arranged at the outer periphery of the head. The at least one first type of tooth cleaning element is a first type of tuft comprising a plurality of filaments. Each filament has a longitudinal axis and a substantially cruciform cross-sectional area extending in a plane substantially perpendicular to the longitudinal axis. The cruciform cross-sectional area has four protrusions and four channels, the protrusions and channels being arranged in an alternating fashion. The at least one first type of tuft has a fill factor in the range of about 40% to about 55%, preferably about 45% to about 50%.

Description

[0001] This application is a divisional application of PCT patent application PCT / US2017 / 034965 (international application date May 30, 2017, priority date June 3, 2016, Chinese national application number 201780034448.7, invention title "Head and oral care tool for oral care tool"), which entered the Chinese national phase on December 3, 2018. Technical Field

[0002] This disclosure relates to a head for an oral care tool, the head comprising at least one first-type tooth cleaning element and at least one second-type tooth cleaning element. The at least one first-type tooth cleaning element is a first-type cluster comprising multiple filaments having a substantially cross-shaped cross-sectional area and disposed within an inner portion of the head, while the at least one second-type tooth cleaning element is disposed at an outer edge of the head. This disclosure also relates to an oral care tool comprising such a head. Background Technology

[0003] Clusters of bristles, consisting of multiple long filaments, are well known in the art for use in oral care tools such as manual and electric toothbrushes. Generally, the cluster is attached to a bristle carrier in a head designed for insertion into the user's mouth. A handle is typically attached to the head and is held by the user during brushing. The head is permanently attached to or repeatedly attached to the handle and is detachable from the handle.

[0004] To effectively clean teeth, appropriate contact pressure must be provided between the free end of the filament and the tooth. Generally, the contact pressure depends on the filament's flexural stiffness and displacement; however, the flexural stiffness of a single filament depends on its length and cross-sectional area. Typically, longer filaments exhibit lower flexural stiffness compared to shorter filaments. However, relatively thin filaments tend to bend more easily, and the relatively low flexural stiffness results in reduced plaque removal efficiency on the tooth surface, as well as less interdental penetration and cleaning performance. To compensate for the aforementioned reduction in flexural stiffness of longer filaments, the cross-sectional area of ​​the filament can be increased. However, relatively thicker filaments can produce an unpleasant brushing sensation and tend to damage the gums in the mouth. Furthermore, thicker filaments can exhibit reduced flexural recovery, and using these filaments can create the impression of worn-down cluster patterns after a relatively short period of use.

[0005] Additionally, filaments with profiles extending along their length, thereby creating non-circular cross-sectional areas, such as polygonal or cross-shaped cross-sections, are also known in the art. Such filaments should improve the cleaning properties of oral care tools during normal use. Specifically, the shaped edges should provide a stronger scraping action during brushing to improve the removal of plaque and other residues from the tooth surface.

[0006] While standard-type toothbrushes, including those with clusters, effectively clean the buccal surfaces of teeth, they are generally not well-suited for adequately removing plaque and debris from interdental areas and other hard-to-reach areas of the mouth, as penetrating into the interdental spaces remains relatively difficult. Specifically, they are not well-suited for adequately cleaning the gum line, where plaque typically begins to grow. Therefore, to achieve and maintain good oral health and prevent gingivitis, it is important to clean along the gum line, specifically along the space between the teeth and periodontal tissues, the so-called gingival sulcus. Inadequate removal of plaque from the gingival sulcus is known to lead to gingivitis, i.e., inflammation of the gum tissue. Furthermore, standard clusters do not provide sufficient capillary action to remove plaque and debris from the tooth and gum surfaces during brushing. However, for good cleaning results, the clusters / filaments must reach the plaque, then break it down, and ultimately remove it. Additionally, the clusters should provide a pleasant sensation to the gums during brushing.

[0007] Furthermore, compared to round filaments, the mechanical stress occurring within the cross-shaped filaments during brushing results in higher stress at the tips of the filaments. This means that, compared to round filaments, cross-shaped filaments must withstand a higher maximum stress value within a cluster with the same overall stiffness. This increased stress within the individual cross-shaped filaments can lead to increased wear behavior during use. This wear is characterized by increased cluster unfolding, resulting in less consumer acceptance.

[0008] One object of this disclosure is to provide a head for an oral care tool that overcomes at least one of the aforementioned deficiencies. Another object of this disclosure is to provide an oral care tool that includes such a head. Summary of the Invention

[0009] According to one aspect, a head for an oral care tool is provided, the head having an outer edge and an inner portion, the head including at least one first-type tooth cleaning element and at least one second-type tooth cleaning element, the at least one first-type tooth cleaning element being disposed at the inner portion of the head, and at least one second-type tooth cleaning element being disposed at the outer edge of the head, the at least one first-type tooth cleaning element being a first-type cluster comprising a plurality of filaments, each filament having a longitudinal axis and a substantially cross-sectional area extending in a plane substantially perpendicular to the longitudinal axis, the cross-sectional area having four protrusions and four channels, the protrusions and channels being arranged in an alternating manner, wherein the at least one first-type cluster has a fill factor in the range of about 40% to about 55%, or about 45% to about 50%.

[0010] According to one aspect, oral care tools including such heads are provided. Attached Figure Description

[0011] The invention is described in more detail below with reference to various embodiments and accompanying drawings, wherein:

[0012] Figure 1 A schematic perspective view of a first exemplary embodiment of an oral care tool including a head according to the present disclosure is shown;

[0013] Figure 2 A schematic perspective view of a second exemplary embodiment of an oral care tool including a head according to the present disclosure is shown;

[0014] Figure 3 A schematic perspective view of a third exemplary embodiment of an oral care tool including a head according to the present disclosure is shown;

[0015] Figure 4 As shown Figures 1 to 3 A schematic cross-sectional view of a filament of a first-type cluster shown;

[0016] Figure 5 A schematic cross-sectional view of a filament according to the prior art is shown;

[0017] Figure 6 A schematic cross-sectional view of an exemplary embodiment of the first type of cluster is shown;

[0018] Figure 7 A schematic cross-sectional view of a cluster according to a first comparative example embodiment is shown;

[0019] Figure 8 A schematic cross-sectional view of a cluster according to a second comparative embodiment is shown;

[0020] Figure 9 A graph comparing the brushing results of the first type of clusters with the brushing results of clusters according to two comparative example embodiments is shown;

[0021] Figure 10 A graph comparing the "slurry absorption quality" of the first type of cluster with the "slurry absorption quality" of the cluster according to two comparative example embodiments is shown;

[0022] Figure 11 A graph comparing the "slurry absorption rate" of the first type of cluster with the "slurry absorption rate" of the cluster according to two comparative example embodiments is shown;

[0023] Figure 12 A schematic cross-sectional view of a rhomboid filament according to the prior art is shown; and

[0024] Figure 13A diagram comparing the gum massage effect of the cross-shaped filaments of the head according to this disclosure with the gum massage effect of the circular filaments of the head is shown; and

[0025] Figure 14 It shows the method for generating Figure 13 The cluster configuration of the data header. Detailed Implementation

[0026] The head of an oral care tool according to this disclosure includes at least one first-type tooth-cleaning element disposed in an internal portion of the head, and at least one second-type tooth-cleaning element disposed at an external edge of the head, i.e., immediately adjacent to the external edge. The at least one first-type tooth-cleaning element is a cluster comprising multiple filaments having a longitudinal axis and a substantially cruciform cross-sectional area extending in a plane substantially perpendicular to the longitudinal axis. The cruciform cross-sectional area has four protrusions and four channels arranged in an alternating manner. The longitudinal axis of the filament is defined by a main extension of the filament. Hereinafter, the extension of the filament along its longitudinal axis may also be referred to as a "longitudinal extension of the filament".

[0027] At least one type of cluster has filaments with a relatively low fill factor in the range of about 40% to about 55%, or in the range of about 45% to about 50%. In the context of this disclosure, the term "fill factor" is defined as the sum of the cross-sectional areas of the filaments in the cluster aperture divided by the cross-sectional area of ​​the cluster aperture. In embodiments where anchoring elements (such as nails) are used to mount the cluster within the cluster aperture, an area of ​​the anchoring device is excluded from the cross-sectional area of ​​the cluster aperture.

[0028] Approximately 40% to 55%, or approximately 45% to 50%, or approximately 49% of the filling factor exhibits a specific void volume within the clusters, yet the filaments still contact each other along a portion of the outer surface. This void volume delivers more toothpaste into the brushing process, and the toothpaste interacts with the teeth for a longer period, contributing to improved brushing effectiveness. Furthermore, the void volume (i.e., the space between the filaments) gains increased absorption of loose plaque due to improved capillary action. In other words, such low filling factors result in more detergent / toothpaste remaining at the filaments / adhering to the filaments for a longer period during brushing. Additionally, the lower cluster density prevents detergent diffusion, leading to an improved overall brushing experience. The toothpaste is better contained within the channels and makes direct contact with the teeth during cleaning, resulting in a greater polishing effect, which is desirable, specifically for removing tooth discoloration.

[0029] In other words, relatively low filler content, ranging from approximately 40% to approximately 55%, or approximately 45% to approximately 50%, or approximately 49%, provides improved brushing efficacy, namely, better removal of plaque and debris from the tooth surface and gums due to improved capillary effects. These capillary effects allow the floss to flow towards the tips / free ends of the filaments, and therefore, allow more of the floss to be applied to the teeth and gums during brushing. Simultaneously, it improves the absorption of plaque and debris from the tooth and gum surfaces.

[0030] Furthermore, due to the cross-shaped geometry of the filaments, each individual filament is stiffer than a round filament when prepared from the same amount of material. However, due to the low filler factor ranging from approximately 40% to approximately 55%, or approximately 45% to approximately 50%, or approximately 49%, the overall stiffness of a cluster made from cross-shaped filaments is reduced compared to a cluster made from round filaments. Surprisingly, such clusters have been found to provide an improved sensory experience, namely a softer feel in the mouth during brushing, while also providing increased cleaning efficacy. The projections of the cross-shaped filaments can easily penetrate the gingival sulcus and other hard-to-reach areas, such as the surfaces of adjacent teeth, scraping the surfaces to loosen plaque, and removing plaque better due to the improved capillary effect of the entire cluster. Due to their specific shape, cross-shaped filaments can penetrate deeper into the gingival sulcus and interproximal areas. In addition, the relatively low filler factor of the first type of cluster allows individual cross-shaped filaments to better conform to the contours of the gingival line and gingival sulcus.

[0031] Because at least one second-type cleaning element is positioned at the outer edge of the head, i.e., at the outer edge of the bristle area, the cleaning element provides increased stability to the first-type bristles, preventing them from spreading out excessively. Therefore, the second-type cleaning element significantly improves the wear behavior and appearance of the first-type bristles, which have a relatively low fill factor, and thus improves lower stability while providing increased cleaning efficacy. Toothbrushes that appear to be used less after brushing, specifically over longer periods, offer higher consumer acceptance.

[0032] Tests have shown that the head of the oral care tool according to this disclosure provides excellent cleaning performance (see [link]). Figures 9 to 11 and Figure 13(As described below). Additionally, tests simulating wear during consumer use showed that this type of brush head exhibited less wear compared to heads consisting only of clusters of cross-shaped filaments. The tests used to simulate “wear” were set up as follows: the toothbrush was run for a total of 36,000 brushing cycles, with 9,000 cycles each at angles of 0°, +45°, -45°, and 0° between the brush head and the bristles. During these cycles, a 7.5% blend solution of Med toothpaste was applied to the brush head. The load on the brush head was set to 4 N. The first 9,000 cycles at 0° were defined as a straight motion over a length of 30 mm; however, the next three 9,000 cycles at +45°, -45°, and 0° were defined as a figure-eight motion over a width of 22 mm and a length of 40 mm. The maximum penetration depth of the filaments into the bristles was set to 7 mm.

[0033] At least one type II dental cleaning element may be a type II cluster or an elastomeric cleaning element, and may have higher flexural stiffness / greater stability than a type I dental cleaning element. In the case where at least one type II dental cleaning element is a type II cluster, the cluster may comprise multiple filaments, each filament having a longitudinal axis and a substantially circular cross-sectional area extending in a plane substantially perpendicular to the longitudinal axis. The cluster may have a fill factor of about 70% to about 80%, thereby providing greater overall flexural stiffness and stability compared to a type I cluster. At least one type II cluster may additionally provide a scrubbing effect on the external tooth surface to adequately clean substantially flat and less sensitive tooth surfaces. In the case where at least one type II dental cleaning element is an elastomeric element, it may be made of TPE material and / or may have the shape of an elastomeric wall extending along a lengthwise extension of the head. Such an elastomeric wall may provide a polishing effect on the external tooth surface and may more completely remove tooth stains. Alternatively, the elastomeric element may have the shape of rubber lumps or fingers for stimulating and massaging the gums.

[0034] Multiple type 1 clusters can be arranged in rows on the inner part of the head, and multiple type 2 tooth-cleaning elements can be arranged in rows on the outer edge of the head. This head configuration can also enhance the functions and beneficial effects described above.

[0035] Each channel of at least one type-first type of cluster of cross-shaped filaments may have a concave curve formed by adjacent and converging protrusions. The concave curve may have a radius ranging from about 0.025 mm to about 0.10 mm, or from about 0.03 mm to about 0.08 mm, or from about 0.04 mm to about 0.06 mm. In other words, the lateral edges of two adjacent protrusions, i.e., two adjacent sides of the protrusions, may converge at the bottom of the channel and define a "converging region." The adjacent protrusions may converge in the converging region in a manner that forms a concave bend (i.e., has an inwardly curved radius) at the bottom of the channel. Compared with standard cross-shaped filaments (see...), this... Figure 5 Compared to (and further described below), the radius is relatively large within this range.

[0036] In the past, it has been observed that conventional cross-shaped filaments (e.g., such as...) Figure 5 The filaments shown and further described below have the disadvantage that these types of filaments can easily trap each other during manufacturing and brushing. However, it has been surprisingly found that the specific geometry / profile of the outer surface of the filaments according to this disclosure allows for improved manufacturability, as the likelihood of filament trapping is significantly reduced when multiple filaments are combined to form a cluster during the so-called “pick-up process”.

[0037] Additionally, the larger radius at the bottom of the channel provides increased stability for the filaments, resulting in less filament damage during toothbrush manufacturing processes, such as when the filaments are picked up and secured to the mounting surface of the brush head during binding or heat tufting processes. In the past, a relatively large number of conventional cross-shaped filaments have been observed to be damaged during the picking process, specifically by the protrusions detaching from the filament or by the filament being cut in the converging area at the bottom of the channel. Cut filaments can provide relatively sharp edges, which can damage / injure oral tissues during brushing.

[0038] Furthermore, surprisingly, it has been found that due to the specific geometry of the concave bend radius, the filaments within the cluster can be better filled with a relatively low fill factor (i.e., in the range of approximately 40% to approximately 55%, or approximately 45% to approximately 50%), as the gap between two adjacent filaments can be maximized. It has been found that it is important for the filaments to exhibit specific gap areas while still remaining in contact with each other. To produce toothbrushes that meet regulatory requirements and are understood by consumers regarding their overall appearance, a consistently high fill factor is generally required (approximately 70% to approximately 80% for round filaments; approximately 80% for diamond-shaped filaments; and approximately 89% for trefoil-shaped filaments). For toothbrushes manufactured using a binding process, a fill factor below approximately 70% results in insufficiently compressed filaments within the cluster openings, and therefore provides insufficient cluster retention. Therefore, providing round filaments with a fill factor below approximately 70% does not meet regulatory requirements. For thermal tufted toothbrushes, a fill factor below approximately 70% allows the plastic melt to penetrate the tuft during the overmolding process, as the pressure of the melt pushes the filaments of the tuft to one side until the filaments contact each other. This creates what is known as multi-peaked tufts, which can damage / impair the gums and thus lead to unsafe products. Besides regulatory and safety concerns, low-filling tufts with rounded filaments will have a "wild" and damaged appearance and will not be acceptable to consumers. However, with the use of cross-shaped filaments with concave bends in the channel and radii ranging from approximately 0.025 mm to approximately 0.10 mm, a smooth and safe product can be achieved that offers an acceptable overall appearance while providing improved cleaning properties.

[0039] Each protrusion in the cross-shaped cross-section region includes two lateral edges extending longitudinally along the filament. These lateral edges generate relatively high concentrated stress on the tooth surface to break down and remove plaque. The outer edges provide a scraping effect, allowing plaque and other debris to loosen more effectively. Due to the relatively large radius of the concave bend at the bottom of the channel, the protrusion provides increased stiffness / stability, making it easier / more effective to loosen / remove plaque from the tooth surface. The channel can then trap the broken plaque and remove it from the tooth. Figure 9 As shown and further explained below, clusters of multiple filaments according to this disclosure provide improved plaque removal from the buccal, lingual, occlusal, and interdental surfaces, as well as along the gingival line, compared to clusters of circular or conventional cross-shaped filaments.

[0040] The cross-shaped cross-sectional area of ​​each filament in the first type of cluster may have an outer diameter. In the context of this disclosure, the outer diameter is defined by the length of a straight line passing through the center of the filament cross-sectional area, with its endpoint located on the outermost circumference of the cross-sectional area. In other words, the cross-shaped cross-sectional area has an imaginary outer circumference in the form of a circle (i.e., an outer enveloping circle), and the outer diameter is defined as the longest straight line segment of the circle passing through its center.

[0041] The outer diameter may be in the range of about 0.15 mm to about 0.40 mm, or about 0.19 mm to about 0.38 mm, or the outer diameter may be in the range of about 0.22 mm to about 0.35 mm, or about 0.24 mm to about 0.31 mm.

[0042] The ratio of the outer diameter to the radius of curvature of the channel can be in the range of about 2.5 to about 12. Alternatively, the ratio of the outer diameter to the radius of curvature of the channel can be in the range of about 2.7 to about 9.

[0043] Surprisingly, this filament geometry has been found to even provide further improved cleaning performance while maintaining brushing comfort in the mouth. Furthermore, this geometry has been found to even help reduce the appearance of filament / tuft wear, as the filaments are even less likely to get trapped during brushing. Additionally, it further improves the manufacturability of such filaments during the toothbrush manufacturing process.

[0044] Each protrusion in the cross-shaped cross-sectional area of ​​the filament of the first type of cluster may have a rounded end, thereby forming a bend. The bend may have a diameter. The diameter of the bend of the protrusion may be in the range of about 0.01 mm to about 0.04 mm, or in the range of about 0.018 mm to about 0.026 mm.

[0045] The ratio of the diameter of the bend in the protrusion to the radius of the bend in the channel can range from about 0.2 to about 1.5, or about 0.3 to about 1.0, or about 0.5 to about 0.7. This is in contrast to the standard cross-shaped filament according to the prior art (see...). Figure 5 Compared to (and further described below), the ratio is relatively low. In other words, the radius of the concave bend of the channel is relatively large relative to the diameter of the bend of the protrusion, i.e., relative to the width extension of the protrusion, or in other words, the diameter of the bend of the protrusion can be relatively thin compared to the radius of the concave bend of the channel. The relatively large radius provides a relatively thin protrusion with increased stability. Therefore, during the toothbrush manufacturing process, specifically when the filament is picked up, the likelihood of filament / protrusion damage or detachment of the relatively thin protrusion is lower. In other words, this further improves the manufacturability of such filaments during the toothbrush manufacturing process.

[0046] Surprisingly, this filament geometry has been found to even provide further improved cleaning performance while maintaining brushing comfort in the mouth. Furthermore, this geometry has been found to help reduce the appearance of filament / tuft wear, as the filaments are even less likely to be trapped during brushing.

[0047] The diameter of the bend in the protrusion can range from about 6% to about 15% of the outer diameter of the filament, or from about 8% to about 12%. Surprisingly, such filaments have been found to conform to the tooth profile even better and penetrate the interdental spaces more easily to remove plaque and debris more completely.

[0048] The protrusions of the cross-shaped filament can taper radially outward, that is, away from the center of the cross-sectional area and towards the outer circumference. These tapered protrusions also ensure access to narrow spaces and other hard-to-reach areas, and may be able to penetrate / enter the interdental region even deeper and more effectively. Because the cross-shaped filament has a higher bending stiffness compared to a circular filament made of the same amount of material, this higher bending stiffness forces the protrusions of the filament to slide more easily into the interdental region.

[0049] The protrusions can taper radially outward at an angle ranging from about 6° to about 25° or from about 8° to about 20°. Surprisingly, this taper has been found to allow for optimal inter-tooth penetration characteristics. Additionally, such filaments can be more easily bundled into clusters without trapping the profiles of adjacent filaments.

[0050] The filaments of the first type of cluster can be substantially cylindrical filaments, meaning the filaments can have substantially cylindrical outward-facing surfaces. In other words, the shape and size of the cross-sectional area of ​​the filament along its longitudinal axis can remain substantially unchanged, i.e., the shape and size of the cross-sectional area can be substantially constant over the longitudinal extension of the filament. In the context of this disclosure, the term "outward-facing surface of the filament" refers to any outer surface or exterior surface of the filament on its side. Compared to tapered filaments, this type of filament provides increased bending stiffness. Higher bending stiffness can further facilitate the filament's insertion into the tooth gaps / spaces. Additionally, cylindrical filaments typically wear slowly, which provides a longer filament life.

[0051] Cylindrical filaments may have substantially rounded tips / free ends to provide gentle cleaning properties. The rounded tips prevent gum injury during brushing. In the context of this disclosure, rounded-end filaments still fall within the definition of substantially cylindrical filaments.

[0052] Alternatively, the filaments of the first type of cluster may include a substantially cylindrical portion and a tapered portion along its longitudinal axis, the tapered portion tapering longitudinally toward the free end of the filament, and the cylindrical portion having a cross-sectional area according to the present disclosure. In other words, the filaments of the first type of cluster may be tapered filaments with a tip. Tapered filaments can achieve optimal penetration into the area between two teeth and into the gingival pocket during brushing, and thus provide improved cleaning properties. The tapered filament may have an overall length extending above the mounting surface of the head in the range of about 8 mm to about 16 mm, optionally about 12.5 mm, and a tapered portion in the range of about 5 mm to about 10 mm measured from the tip of the filament. The tip may be needle-shaped and may include a split end or a feathered end. The tapered portion may be produced by a chemical and / or mechanical tapering process.

[0053] The filaments of the first and / or second types of clusters may be made from polyamides (e.g., nylon) with or without abrasives such as kaolin clay, polybutylene terephthalate (PBT) with or without abrasives such as kaolin clay, and / or polyamide indicator materials (e.g., nylon indicator materials) colored on the outer surface. With prolonged use of the filaments, the coloring on the polyamide indicator material gradually fades, indicating the degree of wear on the filaments.

[0054] The filaments of the first and / or second type of clusters may comprise at least two segments of different materials. At least one segment may comprise a thermoplastic elastomer (TPE) material, and at least one segment may comprise a polyamide (e.g., nylon) with or without an abrasive such as kaolin clay, polybutylene terephthalate (PBT) with or without an abrasive such as kaolin clay, or a polyamide indicator material (e.g., nylon indicator material) colored on the outer surface. These at least two segments may be arranged in a side-by-side or core-skin configuration, which may result in a reduction in the overall stiffness of the filament. A core-skin configuration having an inner / chip segment comprising a harder material (e.g., polyamide or PBT) and an outer / skin segment surrounding the chip segment and comprising a softer material (e.g., TPE) can provide filaments with a relatively soft, outward-facing surface, which may result in mild cleaning properties.

[0055] The filaments of the first and / or second type clusters may contain components selected from: fluoride, zinc, strontium salts, flavoring agents, silica, pyrophosphate, hydrogen peroxide, potassium nitrate, or combinations thereof. For example, fluoride provides a mineralizing effect and thus helps prevent cavities. Zinc can enhance the user's immune system. Hydrogen peroxide can bleach / whiten teeth. Silica can have an abrasive effect to more effectively remove plaque and debris. Pyrophosphate can inhibit the formation of new plaque, tartar, and calculus along the gum line. Filaments containing pyrophosphate can provide long-lasting protection against inflammation of the gums and oral mucosa.

[0056] If multiple such filaments are bundled together to form a cluster, they can be arranged as follows: the filaments on the outer surface of the cluster may contain pyrophosphate to inhibit the formation of plaque, tartar, and calculus along the gingival line, while the filaments arranged in the center of the cluster may contain fluoride to mineralize the teeth during brushing.

[0057] At least one of the components listed above can be coated onto the skin, i.e., onto the outer segment of the filament. In other words, at least some of the filaments in the cluster can include a core-skin structure, wherein the inner / core segment may contain TPE, polyamide, or PBT, and the outer / skin segment may contain at least one of the components listed above. Such a core-skin structure allows one or more components to be applied directly to the teeth at a relatively high concentration, i.e., one or more components can come into direct contact with the teeth during brushing.

[0058] Alternatively, at least one of the components listed above may be co-extruded with TPE, polyamide (e.g., nylon), and / or PBT. Such embodiments allow one or more components to be gradually applied to the teeth as the filament material wears slowly during use.

[0059] At least one first-type cluster attached to the head of an oral care tool may have a longitudinal axis and a cross-sectional area extending in a plane perpendicular to the longitudinal axis. Multiple filaments may be arranged such that the cross-sectional area of ​​the cluster has a scaled-up shape of the corresponding shape of each individual filament constituting the cluster. In other words, the cluster is a scaled-up version of its filaments, meaning the shape of the cross-sectional area of ​​the cluster may have a cross-shaped cross-sectional area substantially the same as that of each individual filament but larger in size. The shape of the cross-sectional area of ​​the cluster may correspond to the shape of the cross-sectional area of ​​its filaments. In the context of this disclosure, the term "cross-sectional area having a scaled-up shape" means a cross-sectional area comprising the same shape but with increased size. In other words, the type of shape may be the same, but the size of the cross-sectional area may differ, i.e., increased. Any gaps, irregularities, embossing, or slots that may exist between two adjacent individual filaments at the outer circumference of the cross-sectional area of ​​the cluster do not contribute to the substantial shape of the cross-sectional area and are therefore ignored.

[0060] Such clusters provide enhanced cleaning properties. As mentioned above, the specific shape / geometry of each individual filament possesses specific cleaning properties that differ from those of conventional filaments with circular cross-sectional areas. These specific cleaning properties can be enhanced by arranging the filaments in such a way that they form the cross-sectional shape of the overall cluster, which is a scaled-up version of the cross-sectional shape of each individual filament. Furthermore, since the specific geometry of each individual filament is generally invisible to the user, the clusters according to this disclosure can convey the corresponding geometry to the user, and thus the corresponding cleaning properties of the filaments constituting the cluster.

[0061] Because the first type of filaments and clusters can each have a cross-sectional area with a non-circular shape, the filaments and the entire cluster can provide anisotropic flexural stiffness characteristics during brushing. When a given contact pressure is applied to the free end of the filament / cluster, the amount of deflection / displacement depends on the diameter / radius of the filament / cluster. A smaller diameter / radius results in greater deflection / displacement at the free end of the filament / cluster, and vice versa; a larger diameter / radius results in less deflection / displacement at the free end of the filament / cluster. The cluster can be arranged on the mounting surface of the head in a manner that provides higher flexural stiffness in the direction where higher cleaning power is required. Lower flexural stiffness can be provided in the direction where gentler cleaning power or a massaging effect is required.

[0062] The oral care tool according to this disclosure can be a toothbrush, which includes a handle and a head. The head extends from the handle and can be repeatedly attached to and detached from the handle, or the head can be non-detachably attached to the handle. The toothbrush can be an electric toothbrush or a manual toothbrush.

[0063] The head may include a bristle carrier having a generally circular or elliptical shape. Such a bristle carrier can be configured for use in an electric toothbrush capable of performing a rotational oscillating motion. The bristle carrier of the electric toothbrush can be driven to rotate or move axially about or along an axis of motion in an oscillating manner, wherein such an axis of motion may extend substantially perpendicular to a plane defined by the upper top surface of the bristle carrier. Clusters according to this disclosure may be attached to the bristle carrier. The projections of the filaments of at least one cluster of the first type can more easily penetrate interdental areas and hard-to-reach areas during the rotational oscillating motion of the head, which can provide further improved cleaning properties of the head. Plaque and other residues can be loosened by the oscillating action of the filaments substantially perpendicular to the tooth surface, while the rotational motion sweeps away plaque and additional residues.

[0064] The head of an oral care tool according to this disclosure may include a bristle carrier having tufting holes (e.g., blind-end holes). The tufts according to this disclosure can be fixed / anchored in the tufting holes by a binding process / anchoring tufting method. This means that the filaments of the tuft are bent / folded in a substantially U-shape around an anchor, for example, made of metal, such as an anchor cable or anchor plate. The filaments are pushed into the tufting holes together with the anchor, such that the anchor penetrates the opposite sidewalls of the tufting holes, thereby anchoring / fixing / fastening the filaments to the bristle carrier. The anchor can be fixed in the opposite sidewalls by positive friction engagement. In the case of blind-end holes, the anchor holds the filaments against the bottom of the hole. In other words, the anchor can be positioned substantially vertically above the U-shaped bend. Because the filaments of the tuft are bent in a substantially U-shaped configuration around the anchor, the first and second branches of each filament extend from the bristle carrier along the filament direction. The type of filament that can be used / suitable for the binding process is also referred to as "double-sided filaments". The head of an oral care tool manufactured by a binding process can be provided in a relatively low-cost and time-efficient manner. Due to the improved geometry of the filaments in at least one first-type cluster according to this disclosure, fewer filaments are damaged (e.g., by cutting) when the filaments are picked up and secured to the mounting surface of the brush head during the binding process. Additionally, when multiple filaments are picked up to form a cluster, fewer filaments are trapped on the outer surfaces of adjacent filaments.

[0065] Alternatively, the cluster can be attached / secured to the head using a thermal tufting process. A method of manufacturing the head of an oral care tool may include the following steps: First, the cluster can be formed by providing a desired amount of filaments according to the present disclosure. Second, the cluster can be placed into a mold cavity such that the ends of the filaments to be attached to the head extend into the cavity. Third, the cluster can be anchored in the head by forming the head or an oral care tool body including a head and a handle around the ends of the filaments extending into the mold cavity using an injection molding process. Alternatively, the cluster can be anchored by forming a first portion (a so-called "sealing plate") of the head around the ends of the filaments extending into the mold cavity using an injection molding process before the rest of the oral care tool can be formed. Before starting the injection molding process, the ends of at least one cluster extending into the mold cavity may optionally be melted or fused together to join the filaments together in a melt or sphere such that the melt or sphere is located within the cavity. The cluster can be held in the mold cavity by a molding bar having a blind hole corresponding to the desired location of the cluster on the finished head of the oral care tool. In other words, the filaments of a tuft attached to the head using a thermal tufting process may not be doubled along their middle portion and may not be mounted in the head using anchors / pins. Tufting processes without anchors can be used to mount the tuft to the head. The thermal tufting manufacturing process allows for complex tuft geometries. For example, the tuft may have a specific morphology / geometry at its free end (i.e., at its upper top surface), which can be shaped to optimally fit the contours of the teeth and further enhance interdental penetration. For example, the morphology may be chamfered or rounded along one or two directions, sharp, or may be straight, concave, or convex. Due to the improved geometry of the filaments of at least one first type of tuft according to this disclosure, fewer filaments are damaged (e.g., by cutting) when the filaments are picked up and secured to the mounting surface of the brush head during the thermal tufting process. Additionally, when multiple filaments are picked up to form a tuft, fewer filaments are trapped on the outer surfaces of adjacent filaments.

[0066] The following is a non-limiting discussion of exemplary embodiments of oral care tools and components thereof according to the present disclosure, with reference to the accompanying drawings.

[0067] Figure 1A perspective top view of a first exemplary embodiment of an oral care tool 10 is shown. This oral care tool can be a manual or electric toothbrush 10, which includes a handle 12 and a head 14 extending longitudinally from the handle 12. The head 14 has a proximal end 41 near the handle 12 and a distal end 40 furthest from the handle 12 (i.e., opposite to the proximal end 41). The head 14 may have a substantially elliptical shape, having a length extension 52 and a width extension 51 substantially perpendicular to the length extension 52. Multiple first-type clusters 16 comprising multiple cross-shaped filaments 20 and multiple second-type clusters 96 comprising multiple circular filaments 74 (e.g., as shown in the image) can be used for hot tufting or binding processes. Figure 7 (As shown) is fixed to the head 14. Clusters 16, 96 can extend substantially vertically from the mounting surface 18 of the head 14. The second type of clusters 96 are arranged in rows on the mounting surface 18 at the outer edge 98, i.e., immediately adjacent to the outer edge 98, along the length extension 52 of the head 14. The first type of clusters 16 are arranged in the inner portion 100 of the head 14, i.e., between the rows of the second type of clusters 96. The first type of clusters 16 have a fill factor in the range of about 40% to about 55%, or about 45% to about 50%, or about 49%. The "fill factor" is defined as the sum of the cross-sectional areas 22 of the filaments 20 divided by the cross-sectional area of ​​the cluster holes.

[0068] Figure 2 A schematic top view of a second exemplary embodiment of the oral care tool 10 is shown. The head 14 includes a plurality of first-type clusters 96 arranged in rows at the inner portion 100 of the head 14. In addition to the plurality of second-type clusters 96, for example, a plurality of elastomeric walls 110 made of TPE material are arranged at the outer edge 98 of the head 14.

[0069] Figure 3 A schematic top view of a third exemplary embodiment of the oral care tool 10 is shown. Similarly, the head 14 includes a plurality of first-type clusters 16 arranged in rows at the inner portion 100 of the head 14. However, in addition to the plurality of second-type clusters 96, a plurality of elastomeric fingers or small pieces 112, for example made of TPE material, are arranged at the outer edge 98 of the head 14.

[0070] like Figure 1 , Figure 2 and Figure 3 As shown, the first type of cluster 16 includes multiple cross-shaped filaments 20 with rounded ends, one of which is shown in... Figure 4 Alternatively, the filament 20 may be a tapered filament comprising a substantially cylindrical portion and a tapered portion along its longitudinal axis. The tapered portion tapers towards the free end of the filament 20, and the cylindrical portion has a cross-sectional region 22 according to the present disclosure.

[0071] Figure 4 A schematic cross-sectional view of the filament 20 of cluster 16 is shown. The filament 20 has a longitudinal axis and a generally cross-shaped cross-sectional area 22 extending in a plane substantially perpendicular to the longitudinal axis. The cross-shaped cross-sectional area 22 has four protrusions 24 and four channels 26. The protrusions 24 and channels 26 are arranged in an alternating manner. Each protrusion 24 tapers at an angle α in the outward direction, the angle ranging from about 6° to about 25°, or from about 8° to about 20°.

[0072] The cross-sectional region 22 has an outer diameter 28 passing through the center 36 of the cross-sectional region 22. The endpoints of the outer diameter 28 are located on the outermost circumference 38 of the cross-sectional region 22. The outer diameter 28 has a length extension in the range of about 0.15 mm to about 0.40 mm, or about 0.19 mm to about 0.38 mm, about 0.22 mm to about 0.35 mm, or about 0.24 mm to about 0.31 mm.

[0073] Each channel 26 has a concave bend 34, meaning the bend curves inward toward the center 36 of the cross-sectional area 22. The concave bend 34 is formed by two adjacent and converging protrusions 24 at the bottom of each channel 26. The concave bend 34 has a radius 30 in the range of about 0.025 mm to about 0.10 mm, or about 0.03 mm to about 0.08 mm, or about 0.04 mm to about 0.06 mm.

[0074] The ratio of the outer diameter 28 to the radius 30 of the concave bend 34 can be in the range of about 2.5 to about 12, or about 2.7 to about 9.

[0075] Each protrusion 24 is rounded at the end, thus forming a bend with a specific diameter 42. The diameter 42 can also be defined as a width extension 42 extending between two opposite lateral edges 44 of the protrusion 24. The ratio of the diameter 42 of the bend of the protrusion 24 to the radius 30 of the bend 34 of the channel 26 is in the range of about 0.2 to about 1.5, or about 0.3 to about 1.0, or about 0.5 to about 0.7.

[0076] Furthermore, the diameter 42 of the circular end of the protrusion 24 is limited to about 6% to about 15%, or about 8% to about 12% of the outer diameter 28 of the filament 20. For example, the diameter 42 of the circular end of the protrusion 24 may be in the range of about 0.01 mm to about 0.04 mm, or in the range of about 0.018 mm to about 0.026 mm.

[0077] Figure 5 A schematic cross-sectional view of a cross-shaped filament 54 according to the prior art is shown. The filament 54 includes the following dimensions:

[0078] Outer diameter 56: 0.295mm

[0079] The radius of the concave bend in the channel is 58: 0.01mm.

[0080] The ratio of the outer diameter of 56 to the radius of the concave bend of 58 is 29.5.

[0081] The protrusion gradually tapers at α: 15°

[0082] The diameter of the bend in the protrusion is 62: 0.04mm.

[0083] The ratio of diameter 62 to radius 58 is 58:4

[0084] Inner diameter 64: 0.1mm.

[0085] Figure 6 A schematic cross-sectional view of a cluster 66 of the first type according to this disclosure is shown (Exemplary Embodiment 1). The cluster 66 has a fill factor of approximately 49%. The filaments 68 of the cluster 66 have the following dimensions:

[0086] Outer diameter 28: 0.309mm

[0087] The radius of the concave bend is 30: 0.06mm

[0088] The ratio of the outer diameter of 28 to the radius of the concave bend of 30 is 5.15.

[0089] The protrusion gradually tapers α: 10°

[0090] The diameter of the bend in protrusion 42 is 0.04 mm.

[0091] The ratio of diameter 42 to radius 30 is 0.67.

[0092] Inner diameter 70: 0.12mm.

[0093] Figure 7 A schematic cross-sectional view of a cluster 72 comprising multiple circular filaments 74 according to the prior art is shown. The diameter of the filaments 74 is approximately 0.178 mm (7 mils). This type of cluster 72 has a fill factor of approximately 77% (Comparative Example 2).

[0094] Figure 8 It shows according to Figure 5 A schematic cross-sectional view of a cluster 76 comprising multiple filaments 54. This type of cluster 76 has a fill factor of approximately 58% (Comparative Example 3).

[0095] Comparative Experiment

[0096] Robot arm testing:

[0097] According to the fact that it includes multiple filaments 68 Figure 6Cluster 66 (cluster diameter: 1.7 mm) (Exemplary embodiment 1), including multiple filaments 74 according to Figure 7 Cluster 72 (cluster diameter: 1.7 mm) (Comparative Example 2) and the basis including multiple filaments 54 Figure 8 Cluster 76 (cluster diameter: 1.7 mm) (Comparative Example 3) were compared regarding their plaque removal efficacy on typodonts.

[0098] The brushing test was performed using the KUKA 3 robotic arm system under the following conditions (see Table 1):

[0099]

[0100] Table 1

[0101] Figure 9 The amount (%) of plaque replacement removed by exemplary embodiments 1, comparative example 2 and comparative example 3 relative to all tooth surfaces 78, buccal surface 80, lingual surface 82, lingual and buccal surfaces 84, occlusal surface 86, gingival line 88 and interdental surface 90 is shown.

[0102] Figure 9 As clearly shown, compared to Comparative Examples 2 and 3, Exemplary Embodiment 1 provides significantly improved plaque removal properties relative to all tooth surfaces 78, buccal surface 80, lingual surface 82, lingual and buccal surfaces 84, occlusal surface 86, gingival line 88, and interdental surface 90. The most significant improvement in cleaning performance occurs on occlusal surface 86, with improvements of 22% and 9%, respectively.

[0103] Slurry absorption test:

[0104] Figure 10 A graph is shown illustrating the "slurry absorption quality" of a first-type cluster (cluster diameter: 1.7 mm) (Exemplary Embodiment 4) with a fill factor of approximately 46% compared to that of a cluster including rhomboid filaments (see Figure 4). Figure 12 The "slurry absorption quality" of a cluster (cluster diameter: 1.7 mm) with a fill factor of approximately 80% (Comparative Example 5) was compared with the "slurry absorption quality" of cluster 72 with a fill factor of approximately 77% according to Comparative Example 2.

[0105] The filament of exemplary embodiment 4 has the following dimensions:

[0106] Outer diameter: 0.269mm

[0107] The radius of the concave bend in the channel is 0.05mm.

[0108] The ratio of the outer diameter to the radius of the concave bend: 5.38

[0109] The protrusion gradually tapers α: 14°

[0110] The diameter of the bend in the protrusion is 0.029 mm.

[0111] The ratio of the diameter of the protrusion's bend to the radius of the concave bend of the channel: 0.58

[0112] Inner diameter: 0.102mm

[0113] The filament of Comparative Example 5 has the following dimensions (see Figure 12 ):

[0114] The longer diagonal length is 92: 0.29mm

[0115] The shorter diagonal length is 94: 0.214 mm.

[0116] Figure 11 A graph is shown comparing the "slurry absorption rate" of Exemplary Embodiment 4 with the "slurry absorption rate" of Comparative Examples 2 and 5.

[0117] Test Description :

[0118] The brush head, comprising the clusters according to Exemplary Embodiment 4 and Comparative Examples 2 and 5, is fixed in a horizontal position with the filaments pointing downwards. A bowl of toothpaste slurry (toothpaste:water = 1:3) with a scale is placed directly below the brush head. The scale is used to measure the amount of slurry in the bowl. At the start of the test, the toothbrush is moved downwards at 100 mm / s and immersed 2 mm deep into the slurry. Then, the toothbrush is held in the toothpaste slurry for 5 seconds and pulled out again at 100 mm / min. The force along the vertical direction is measured over time.

[0119] Figure 10 and Figure 11 As clearly shown, compared to Comparative Examples 2 and 5, Exemplary Embodiment 4 provides significantly improved "slurry absorption" in terms of both quality and speed. The increased void volume within the cluster of Exemplary Embodiment 4 enhances capillary action. This results in increased absorption of the toothpaste (slurry), allowing the toothpaste to interact with / contribute to the brushing process for a longer period. The cluster of Exemplary Embodiment 4 can absorb more than 50% of the toothpaste slurry at a higher absorption rate of about 50%, resulting in improved teeth cleaning. In other words, in addition to delivering more toothpaste to the brushing process, the specific void volume within the cluster of Exemplary Embodiment 4 also enables increased absorption of loose plaque. This results in improved overall clinical performance of the toothbrush, which includes a head having a cluster configuration according to this disclosure.

[0120] Figure 13A graph comparing the "perceived gum massage" characteristics of cross-shaped filaments with those of round filaments is shown. As illustrated, brush heads 202 and 204, which include cross-shaped filaments with lower stiffness (cN / mm²) (x-axis), achieve a higher level of gum massage intensity (y-axis) compared to brush heads 206 and 208 with round filaments. In other words, brush heads 202 and 204 provide an improved gum massage / feel due to the specific structure of the cross-shaped filaments.

[0121] The arrangement of the clusters of brush heads 202 and 204 is shown in... Figure 14 The cluster configurations of brush heads 202 and 204 are as follows:

[0122] Brush head 202 Brush head 204 Fill factor 55％ 49％ Cluster diameter 1.7mm 1.7mm filament outer diameter 28 0.30mm 0.38mm

[0123] The cluster configuration of brush heads 206 and 208 is composed of Figure 14 Combining Tables 2 and 3, it is evident that all clusters have a diameter of 1.7 mm.

[0124]

[0125] Table 2: Cluster configuration of toothbrush 206

[0126]

[0127] Table 3: Cluster configuration of toothbrush 206

[0128] In the context of this disclosure, the term "substantially" refers to an arrangement of elements or features that, while theoretically expected to exhibit precise consistency or behavior, may in practice make something appear somewhat imprecise. Similarly, the term represents the degree to which quantitative values, measurements, or other relevant representations may differ from the reference without causing a change in the fundamental function of the subject matter.

[0129] The dimensions and values ​​disclosed herein should not be construed as strictly limited to the precise numerical values ​​cited. Rather, unless otherwise specified, each such dimension is intended to represent the stated value and a functionally equivalent range around that value. For example, a dimension disclosed as “40 mm” is intended to represent “approximately 40 mm”.

Claims

1. A head (14) for an oral care tool (10), the head (14) having an outer edge (98) and an inner portion (100), the head (14) comprising at least one first-type tooth cleaning element and at least one second-type tooth cleaning element, the at least one first-type tooth cleaning element being disposed at the inner portion (100) of the head (14), and the at least one second-type tooth cleaning element being disposed at the outer edge (98) of the head (14). The at least one first-type dental cleaning element is a first-type cluster (16, 66), which comprises multiple filaments (20, 68), each filament (20, 68) having a longitudinal axis and a cross-shaped cross-sectional area (22) extending in a plane perpendicular to the longitudinal axis. The cross-shaped cross-sectional area (22) has four protrusions (24) and four channels (26), which are arranged alternately. The cross-section of each filament (20, 68) of the at least one first-type cluster (16, 66) is... The surface area (22) has an outer diameter (28), and each channel (26) of the filaments (20, 68) of the at least one first type cluster (16, 66) has a concave bend (34) formed by adjacent and converging protrusions (24), the concave bend (34) having a radius (30), and the ratio of the outer diameter (28) to the radius (30) of the concave bend (34) of the channel (26) is in the range of 2.5 to 12, wherein the at least one first type cluster (16, 66) has a fill factor in the range of 40% to 49%. The at least one second-type dental cleaning element is a second-type cluster (96), the second-type cluster comprising multiple filaments (74), each filament (74) having a longitudinal axis and a circular cross-sectional area (102) extending in a plane perpendicular to the longitudinal axis, wherein the second-type cluster has a fill factor in the range of 70% to 80%.

2. The head (14) according to claim 1, wherein the ratio of the outer diameter (28) to the radius (30) of the concave bend (34) of the channel (26) is in the range of 2.7 to 9.

3. The head (14) according to claim 1, wherein the at least one first type of cluster (16, 66) has a fill factor in the range of 45% to 49%.

4. The head (14) according to any one of claims 1 to 3, wherein a plurality of first-type tooth cleaning elements are arranged in a row at the inner portion (100) of the head (14), and a plurality of second-type tooth cleaning elements are arranged in a row at the outer edge (98) of the head (14).

5. The head (14) according to any one of claims 1 to 3, wherein the radius (30) of the concave bend (34) of the channel (26) is in the range of 0.025 mm to 0.10 mm.

6. The head (14) according to claim 5, wherein the radius (30) of the concave bend (34) of the channel (26) is in the range of 0.03 mm to 0.08 mm.

7. The head (14) according to claim 6, wherein the radius (30) of the concave bend (34) of the channel (26) is in the range of 0.04 mm to 0.06 mm.

8. The head (14) according to any one of claims 1 to 3, wherein the cross-sectional region (22) of each filament (20, 68) of the at least one first type of cluster (16, 66) has an outer diameter (28) in the range of 0.15 mm to 0.40 mm.

9. The head (14) according to claim 8, wherein the cross-sectional region (22) of each filament (20, 68) of the at least one first type of cluster (16, 66) has an outer diameter (28) in the range of 0.19 mm to 0.38 mm.

10. The head (14) according to claim 9, wherein the cross-sectional region (22) of each filament (20, 68) of the at least one first type of cluster (16, 66) has an outer diameter (28) in the range of 0.22 mm to 0.35 mm.

11. The head (14) according to claim 10, wherein the cross-sectional region (22) of each filament (20, 68) of the at least one first type of cluster (16, 66) has an outer diameter (28) in the range of 0.24 mm to 0.31 mm.

12. The head (14) according to any one of claims 1 to 3, wherein each protrusion (24) of the cross-sectional region (22) of the filament (20, 68) of the at least one first type cluster (16, 66) is end-rounded, thereby forming a bend having a diameter (42), and the diameter (42) of the bend of the protrusion (24) is in the range of 0.01 mm to 0.04 mm.

13. The head (14) according to claim 12, wherein the diameter (42) of the curvature of the protrusion (24) is in the range of 0.018 mm to 0.026 mm.

14. The head (14) according to any one of claims 1 to 3, wherein each protrusion (24) of the cross-sectional area (22) of the filament (20, 68) of the at least one first type of cluster (16, 66) is end-rounded, thereby forming a bend having a diameter (42), and the ratio of the diameter (42) of the bend of the protrusion (24) to the radius (30) of the concave bend (34) of the channel (26) is in the range of 0.2 to 1.

5.

15. The head (14) according to claim 14, wherein the ratio of the diameter (42) of the bend of the protrusion (24) to the radius (30) of the concave bend (34) of the channel (26) is in the range of 0.3 to 1.

0.

16. The head (14) according to claim 15, wherein the ratio of the diameter (42) of the bend of the protrusion (24) to the radius (30) of the concave bend (34) of the channel (26) is in the range of 0.5 to 0.

7.

17. The head (14) according to any one of claims 1 to 3, wherein each protrusion (24) of the cross-shaped cross-sectional area (22) of each filament (20, 68) of the at least one first type of cluster (16, 66) gradually tapers in the outward direction.

18. The head (14) according to claim 17, wherein each protrusion (24) tapers gradually in the outward direction at an angle defined in the range of 6° to 25°.

19. The head (14) according to claim 18, wherein each protrusion (24) tapers gradually along the outward direction at an angle defined in the range of 8° to 20°.

20. The head (14) according to any one of claims 1 to 3, wherein each filament (20, 68) of the at least one first type of cluster (16, 66) comprises a cylindrical portion and a tapered portion along its longitudinal axis, the tapered portion tapering toward the free end of the filament, and the cylindrical portion having the cross-shaped cross-sectional area (22).

21. The head (14) according to any one of claims 1 to 3, wherein the first type of cluster (16, 66) has a longitudinal axis and a cross-sectional area extending in a plane perpendicular to the longitudinal axis, and the plurality of filaments (20, 68) are arranged such that the cross-sectional area of ​​the first type of cluster (16, 66) has a shape that is enlarged relative to the shape of the cross-sectional area of ​​each filament (20, 68).

22. An oral care tool (10) comprising a head (14) according to any one of claims 1 to 21.

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