Interdental brush having an oval wire cross-section and method for manufacturing the same

Abstract

The present invention relates to an interdental brush (1, 1') comprising a brush part (2) having two mutually twisted legs (4A, 4B) of a wire section (4) and a brush filament (5) sandwiched between the legs (4A, 4B), and to a method for manufacturing such an interdental brush (1, 1'). In particular, in order to improve the bending fatigue strength of the wire section (4), the present invention uses a wire section (4) made of austenitic steel having a chromium content of 15% to 17% by weight, a manganese content of 12% to 16% by weight and a molybdenum content of 0 to 4% by weight, and forms the wire section (4) with an oval cross section with an oval ratio O ranging from 0.4 to 0.9, the oval ratio O being measured as the ratio between the length (LQk) of the minor axis (Qk) and the length (LQg) of the major axis (Qg) of the cross section.

Description

Technical Field

[0001] The present invention relates to an interdental brush comprising a brush part having two leg pieces twisted together in the wire part and brush filaments sandwiched between the leg pieces. Furthermore, the present invention relates to a method for manufacturing such an interdental brush.

Background Art

[0002] Interdental brushes are known from the prior art. An interdental brush generally has a grip part or a part for fixing the interdental brush to a handgrip, and a brush part attached to the grip part or the fixing part for cleaning the interdental space. To manufacture an interdental brush, brush filaments are held between leg pieces so as to extend laterally with respect to the leg pieces of the wire part, and then twisted together with the leg pieces, whereby they are tightened therebetween, whereby the outer contour of the brush part assumes a helical shape.

[0003] For example, German Patent Application Publication No. 102018101085 relates to a twisted brush. This brush has a hair support consisting of wire parts twisted together, and the wire parts have an oval and / or elliptical cross-section at least in the distal part of the hair support. Furthermore, a twisted brush is also proposed in which the hair support has anti-pulling means at a distance from its proximal end. By this anti-pulling means, the hair support is prevented from being pulled out and can be fixed to the grip of the twisted brush. A method for manufacturing a twisted brush is also further proposed, in which method the wire parts have at least one of them shaped, i.e., having at least two regions with different cross-sections, and are twisted together to form a hair support.

[0004] The European Patent No. 1470765 of the applicant of the present application relates to an interdental brush and a method for manufacturing such a brush. In the interdental brush, filaments or bristles are held between two wire portions twisted together and made of austenitic steel. The interdental brush and the method are characterized by good rigidity with a relatively small diameter of the wire portions.

[0005] In practice, in the interdental brushes known from the prior art, the brushes are prone to early breakage. Specifically, it has been found that there is a tendency, particularly in the transition region between the brush part and the grip part, where the wire part is frequently exposed to bending changes when the angle between the grip part and the brush part is frequently and variably guided into the interdental space.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] The problem of the present invention is to reduce the drawbacks occurring in the interdental brushes known from the prior art. In particular, one problem of the present invention is to improve the bending fatigue strength of the wire part.

Means for Solving the Problems

[0008] These problems are solved by the interdental brush according to claim 1 and the method according to claim 9 described therein.

[0009] In particular, these problems are solved by an interdental brush having a brush part with two leg pieces of a wire part twisted together with each other and brush filaments clamped between the leg pieces, wherein the wire part is made of austenitic steel having a chromium content of 15% by weight to 17% by weight, a manganese content of 12% by weight to 16% by weight, and a molybdenum content of 0% to 4% by weight, and has an oval cross-section with an ovality O in the range from 0.4 to 0.9, and the ovality O is measured as the ratio of the length of the minor axis to the length of the major axis of the cross-section.

[0010] In a method for manufacturing an interdental brush according to the present invention, these problems are solved, in particular, by twisting two leg pieces of a wire part together with each other to produce a brush part of the interdental brush, clamping the brush filaments held between the leg pieces, and in so doing, using a wire part made of austenitic steel having a chromium content of 15% by weight to 17% by weight, a manganese content of 12% by weight to 16% by weight, and a molybdenum content of 0% to 4% by weight, and shaping the wire part to have an oval cross-section with an ovality O in the range from 0.4 to 0.9, wherein the ovality O is measured as the ratio of the length of the minor axis to the length of the major axis of the cross-section.

[0011] The solution according to the present invention has the advantage that the selected alloy provides a steel that is particularly tough yet sufficiently rigid, with particularly good bending fatigue strength. The bending fatigue strength is further improved by the selected ovality, especially in the transition region between the brush part and the grip part where the wire part is frequently exposed to bending changes. Thus, according to the present invention, a dental brush is provided that allows frequent bending changes and is therefore continuously and flexibly usable, especially long-lasting.

[0012] The solution means according to the present invention can optionally be supplemented and improved by the following other forms which are each advantageous in themselves. In this case, it can be easily and clearly recognized by those skilled in the art that the product features of the interdental brush according to the present invention also appear as each step of the method according to the present invention, and vice versa.

[0013] According to another form of the present invention, it is assumed that the twisted leg pieces have a winding strip having a winding strip length measured parallel to the brush longitudinal axis and smaller than 1.5 times the maximum outer diameter of the wire part. The length of the untwisted leg pieces measured parallel to the brush longitudinal axis exceeds the length of the twisted leg pieces measured parallel to the brush longitudinal axis by a factor of 1.6 to 2.4, preferably by a factor of 1.8 to 2.2, and most preferably by a factor of 2. Thus, a particularly densely twisted brush part can be provided. Dense twisting, on the one hand, generally helps to increase the density or amount of brush filaments that can be tightened between the leg pieces. On the other hand, dense twisting, in this case, helps to further improve the bending strength and elasticity of the brush part by increasing the spring force.

[0014] According to another form of the present invention, it is assumed that the depth of the winding strip measured as the difference between the maximum outer diameter and the minimum inner diameter is smaller than 0.05 times to 0.2 times the maximum outer diameter, preferably smaller than 0.075 times to 0.15 times, and most preferably smaller than 0.1 times. In this case, the particularly small depth of the winding strip further enhances the density and compactness of the brush part, which helps to further improve the bending strength and elasticity of the brush part. Additionally, the particularly small depth of the winding strip results in a reduction and smoothing of the surface of the brush part, thereby reducing the deposition of contaminants and bacteria.

[0015] According to another form of the present invention, it is assumed that the wire has an original cross-section in the shape of an ellipse where the ratio of the length of the semi-major axis of the ellipse to the length of the semi-minor axis of the ellipse is from 1.4 to 1.6. Such an elliptical cross-section of the wire by itself helps to further improve the bending strength and elasticity of the brush part. The elliptical cross-sectional shape of the wire can also reduce the depth of the winding strip of the brush part or the depth of the seam formed between the leg pieces of the brush part, whereby in addition to the increase in bending strength and elasticity, the surface of the brush part can be additionally reduced and the brush part can be smoothed, and in this case, this also helps to further reduce the deposition of contaminants and bacteria.

[0016] According to another form of the present invention, it is assumed that the ratio of the length of the semi-major axis of the ellipse to the length of the semi-minor axis (LHk) of the ellipse is from 1.5 to 1.55. For example, the ratio of the length of the semi-major axis of the ellipse to the length of the semi-minor axis of the ellipse may be essentially 1.53. Thus, on the one hand, the above-mentioned advantages of improving the bending strength and elasticity of the brush part and on the other hand, reducing and smoothing the surface of the brush part can be further improved.

[0017] It is also conceivable that the wire part is provided with a coating. The coating thickness of the coating can correspond to approximately half of the thickness of the brush filament. The brush filament may be embedded in the coating. The coating and embedding help to further smooth and reduce the surface of the brush part, and also help to close the holes, capillaries and other openings that may occur between the twisted leg pieces of the wire part or between the brush filaments. Therefore, the deposition of contaminants and bacteria can be further reduced.

[0018] According to another form of the present invention, it is assumed that the number of brush filaments per winding strip is greater than 10. Advantageously, the number of brush filaments per winding strip may be greater than 25. A number of filaments from 40 to 60 per winding strip, for example about 50, may be considered most advantageous. Thus, a particularly high density of brush filaments can be achieved, which are arranged so as to be as closely in contact with each other as possible and / or overlap along the brush portion in a spiral shape. This helps to further improve the cleaning effect and use comfort of the interdental brush according to the present invention.

[0019] According to another form of the present invention, it is assumed that the effective length of the brush filament, measured transversely to the brush longitudinal axis between the outer contour of the twisted wire portion and the free end of the brush filament, is from 4 to 5 times the maximum outer diameter. Thus, the proportion of the volume of the interdental brush that the contour of the brush filament as a whole is required for greatly exceeds the volume occupied by the wire portion. This helps to further improve the cleaning effect and use comfort of the interdental brush according to the present invention.

[0020] According to another form of the present invention, it is assumed that the ratio of the maximum outer diameter of the wire and / or the maximum wire diameter to the maximum filament diameter of the brush filament is from 4 to 4.6. Such a ratio improves the adjustment between the elasticity and rigidity of the wire portion on the one hand and the brush filament on the other hand. Thus, the use comfort and service life of the interdental brush according to the present invention can be further enhanced.

[0021] According to another form of the present invention, it is assumed that the free brush end has a rounded portion, and the maximum rounded portion diameter of the rounded portion is larger than the maximum outer diameter. For example, the free brush end is at least partially formed in a spherical shape. The rounded portion helps to avoid or at least reduce sharp edges and corners at the free brush end. Thus, the risk of injury is reduced and the use comfort is further improved.

[0022] According to another form of the present invention, it is assumed that the austenitic steel has a nitrogen content of 0.5% by weight, a silicon content of 0.25% by weight, a carbon content of 0.11% by weight, and a nickel content of less than 0.05% by weight. Further, in this case, such an alloy serves to provide a particularly tough and sufficiently rigid steel having particularly good bending fatigue strength. Further, in this case, a very small nickel content of less than 0.05% by weight serves to provide an interdental brush according to the present invention having the highest possible biocompatibility.

[0023] In the method of manufacturing an interdental brush, the solution according to the present invention can be further improved by stretching the brush part along the brush longitudinal axis after twisting. For example, the stretching ratio of the stretched length to the non-stretched length of the brush part may be greater than 1 to greater than 1.2, preferably greater than 1.05 to greater than 1.15, and most preferably 1.1. Therefore, the density, elasticity and bending fatigue strength of the brush part can be further increased.

[0024] Other advantageous forms and combinations of features of the present invention will be apparent from the following detailed description and the entire scope of the claims.

Brief Description of the Drawings

[0025] To better understand the present invention, the following attached drawings are referred to. The drawings only show possible embodiments of the subject matter of the present invention, in which case, as described above, the illustrated features may be arbitrarily combined with each other or omitted according to the requirements of each case.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Mode for Carrying Out the Invention

[0026] FIG. 1 shows a schematic perspective view of an interdental brush 1 according to the present invention. The interdental brush 1 has a brush part 2 and a grip part 3, and the grip part 3 is housed in an operating device 3A. The brush part 2 has a wire part 4, and brush filaments 5 are held on the wire part 4. At least the brush part 2 and the grip part 3 extend substantially parallel to the brush longitudinal axis L of the interdental brush 1.

[0027] FIG. 2 shows a schematic side view of the brush part 2 of the interdental brush 1 shown in FIG. 1. Here, it is clear that the brush filaments 5 extend radially away from the wire part 4 so as to extend substantially perpendicular to the brush longitudinal direction axis L. At the same time, the brush filaments 5 form a certain kind of helix that wraps around the wire part 4 together. The outer diameter DB of the brush part 2 measured in the lateral direction with respect to the brush longitudinal axis is 2.5 mm in the embodiment of the interdental brush 1 shown in FIG. 2.

[0028] Figure 3 shows a schematic cross-sectional view of the wire portions 4A and 4B of the interdental brush 1 shown in FIGS. 1 and 2 in the non-twisted state U. The non-twisted wire portions 4A and 4B of the interdental brush 1 have an elliptical cross-section. In this embodiment, the major axis of the ellipse has a length LHg of about 0.26 mm, and the minor axis of the ellipse has a length LHk of about 0.17 mm.

[0029] Figure 4 shows a schematic cross-sectional view of one of the brush filaments 5 of the interdental brush 1 shown in FIGS. 1 to 3. The brush filament 5 has a cross-section with a filament diameter DF of about 0.0635 mm in this embodiment.

[0030] Figure 5 shows a schematic side view of the brush portion 4 of another embodiment of the interdental brush 1' according to the present invention. Here too, it is clear that the brush filaments 5 extend radially away from the wire portion 4 so as to extend substantially perpendicular to the brush longitudinal axis L. At the same time, the brush filaments 5 form a kind of spiral or chord winding around the wire portion 4 together. The outer diameter DB of the brush portion 2 measured in the lateral direction with respect to the brush longitudinal axis is about 2.2 mm in the embodiment of the interdental brush 1' shown in FIG. 5.

[0031] Figure 6 shows a schematic cross-sectional view of the wire portions 4A and 4B of the interdental brush 1' shown in FIG. 5 in the non-twisted state U. The non-twisted wire portions 4A and 4B of the interdental brush 1' also have an elliptical cross-sectional shape. In this embodiment, the major axis of the ellipse has a length LHg of about 0.23 mm, while the minor axis of the ellipse has a length LHk of about 0.15 mm.

[0032] Figure 7 shows a schematic cross-sectional view of the brush filaments 5 of the interdental brush 1' shown in FIGS. 5 and 6. The brush filament 5 has a cross-section with a filament diameter DF of about 0.0508 mm in this embodiment.

[0033] FIG. 8 shows a schematic side view of a part of the interdental brushes 1, 1' according to the present invention. The wire portion 4 is in a twisted state V with its leg pieces 4A, 4B twisted together. In the twisted state V, the leg pieces 4A, 4B, together with the brush filaments 5 sandwiched between the leg pieces, are spirally wound around the brush longitudinal axis L. In the present embodiment, the winding length S of the winding measured substantially parallel to the brush longitudinal axis L is smaller than 1.5 times the maximum outer diameter DD of the wire portion 4.

[0034] Furthermore, the brush filament 5 has an effective length LN. With this effective length LN, the brush filament 5 extends radially away from the wire portion 4 in the twisted state V, measured substantially perpendicular to the brush longitudinal axis L. Advantageously, the effective length LN is between 3.8 times and 16 times the maximum outer diameter DD of the wire portion 4. Preferably, the effective length LN is between 4 times and 10 times the maximum wire diameter. Further, a rounded portion 7 is provided at the free brush end 6. The rounded portion 7 is formed by, for example, compression processing and / or other types of plastic deformation in order not to damage the brush filaments usually made of plastic, and is preferably formed by cold deformation.

[0035] FIG. 9 shows a schematic cross-sectional view of the interdental brushes 1, 1' shown in FIG. 8 along the cutting line A-A entered in FIG. 8. Here, the rounded portion has a rounded portion diameter DA measured perpendicular to the brush longitudinal direction axis L, and it is clear that this rounded portion diameter DA exceeds the maximum outer diameter DD of the wire portion 4. The seam 8 formed between the leg pieces 4A, 4B in the twisted state V has a depth T measured perpendicular to the brush longitudinal axis L, and this depth T is obtained from the difference between the maximum wire diameter DD and the minimum diameter or inner diameter Di of the wire portion 4 measured at the bottom of the seam 8.

[0036] FIG. 10 shows a schematic cross-sectional view of the leg pieces 4A, 4B of the interdental brushes 1, 1' in the twisted state V. Here, it is clear that the leg pieces 4A, 4B each have an oval cross-section having a major axis Qg with a length LQg and a minor axis Qg with a length LQk. The ovality O of the cross-section measured as the ratio between the length LQk of the minor axis Qk and the length LQg of the major axis Qg is preferably between 0.4 and 0.9.

[0037] FIG. 11 shows a schematic perspective view of an apparatus 100 for measuring the buckling resistance Fw of the interdental brushes 1, 1'. The interdental brushes 1, 1' are fixed and housed in a holder (not shown) by their grip portions 3A. The holder, on the other hand, is movable relative to the apparatus 100 in a direction extending substantially parallel to the brush longitudinal axis L. The apparatus has a plunger 101, a housing plate 102, and two clamp jaws 103A, 103B. The plunger 101 is fixed so as to be housed in the housing plate 102. The housing plate 102 is clamped and held between the clamp jaws 103A, 103B.

[0038] The free brush end 6 is placed on the plunger 101. The buckling force Fk acting on the free brush end 6 directed substantially parallel to the brush longitudinal axis L can be measured by the plunger 102 and / or the housing plate 102. The buckling force Fk opposes the buckling resistance Fw exerted from the interdental brushes 1, 1' or the brush portion 2 of the interdental brushes 1, 1' when the interdental brushes 1, 1' are moved in the direction of the apparatus 100. At that time, when the buckling force Fk exceeds the buckling resistance Fw, the wire portion 4 of the brush portion 2 buckles.

[0039] The buckling resistance Fw may be used as an index of the bending fatigue strength of the interdental brushes 1, 1' or the wire portion 4 of the interdental brushes 1, 1'. The buckling resistance Fw and the bending fatigue strength usually should behave proportionally to each other. In short, in other words, it holds that the higher the buckling resistance Fw of the wire portion 4, the higher the bending fatigue strength.

[0040] In the buckling test performed using the device 100, it was found that the interdental brushes 1 and 1' according to the present invention, which are manufactured from a wire having an original elliptical cross-section, can be applied with a buckling resistance Fw significantly higher than that of the interdental brushes made from a wire having a circular cross-section according to the prior art. Therefore, for example, the interdental brushes 1 and 1' according to the present invention, which are manufactured from an elliptical wire having a semi-minor axis with a length LHk of 0.15 mm and a semi-major axis with a length LHg of 0.25 mm, can exert a buckling resistance Fw with a measured minimum value of 2.17 Newtons, a measured maximum value of 2.69 Newtons, a standard deviation of 0.19 Newtons, and an average of 2.52 Newtons. In contrast, for an interdental brush according to the prior art, having a wire diameter of 0.18 mm and a circular cross-section, and comparable in wire cross-sectional area, only a buckling resistance Fw with a measured minimum value of 1.58 Newtons, a measured maximum value of 1.70 Newtons, a standard deviation of 0.05 Newtons, and an average of 1.63 Newtons can be exerted. Therefore, the interdental brushes 1 and 1' according to the present invention are significantly superior to the interdental brushes according to the prior art in terms of the buckling resistance Fw exerted by the interdental brush, and thus also in terms of the bending fatigue strength of the interdental brush.

[0041] Variations of the foregoing embodiments are possible within the scope of the idea of the present invention. Although the present application relates to the invention described in the claims, it includes the following as other aspects. 1. In an interdental brush (1, 1') comprising a brush part (2) having two leg pieces (4A, 4B) of a wire part (4) twisted together and a brush filament (5) sandwiched between the leg pieces (4A, 4B), the wire part (4) is made of austenitic steel having a chromium content of 15% by weight to 17% by weight, a manganese content of 12% by weight to 16% by weight, and a molybdenum content of 0 to 4% by weight, has an oval cross-section with an ovality O in the range from 0.4 to 0.9, and the ovality O is measured as the ratio of the length (LQk) of the minor axis (Qk) to the length (LQg) of the major axis (Qg) of the cross-section characterized in that, the interdental brush (1, 1'). 2. The twisted leg pieces (4A, 4B) have a winding length (S) measured parallel to the brush longitudinal axis (L) that is less than 1.5 times the maximum outer diameter (D) of the wire part (4), characterized in that, the interdental brush (1, 1') of item 1 above. 3. The depth (T) of the winding measured as the difference between the maximum outer diameter (D) and the minimum inner diameter (Di) is less than 0.05 times to 0.2 times the maximum outer diameter (D), characterized in that, the interdental brush (1, 1') of item 1 or 2 above. 4. The wire has an original cross-section in the shape of an ellipse where the ratio of the length (LHg) of the semi-major axis to the length (LHk) of the semi-minor axis of the ellipse is 1.4 to 1.6, characterized in that, the interdental brush (1, 1') of any one of items 1 to 3 above. 5. The ratio of the length (LHg) of the semi-major axis to the length (LHk) of the semi-minor axis of the ellipse is 1.5 to 1.55, characterized in that, the interdental brush (1, 1') of item 4 above. 6. The number of brush filaments (5) per winding is greater than 10, characterized in that, the interdental brush (1, 1') of any one of items 1 to 5 above. 7. The effective length (LN) of the brush filament (5) measured transversely to the brush longitudinal axis between the outer contour of the twisted wire part (4) and the free end of the brush filament (5) is 3.8 times to 16 times the maximum outer diameter (D), characterized in that, the interdental brush (1, 1') of any one of items 1 to 6 above. 8. The interdental brush (1, 1') according to any one of 1 to 7 above, characterized in that the ratio of the maximum outer diameter (D) and / or the maximum wire diameter (DD) of the wire to the maximum filament diameter (DF) of the brush filaments (5) is between 4 and 4.6. 9. The interdental brush (1, 1') according to any one of 1 to 8 above, characterized in that the free brush end (6) has a rounded portion, and the maximum rounded portion diameter (DA) of the rounded portion is larger than the maximum outer diameter (D). 10. The austenitic steel has a nitrogen content of 0.5% by weight, a silicon content of 0.25% by weight, a carbon content of 0.11% by weight, and a nickel content of less than 0.05% by weight. The interdental brush (1, 1') according to any one of 1 to 9 above. 11. In a method of manufacturing an interdental brush (1, 1'), in order to produce the brush part (2) of the interdental brush (1, 1'), two leg pieces (4A, 4B) of the wire part (4) are twisted together, and the brush filaments (5) held between the leg pieces (4A, 4B) are tightened. Using a wire part (4) made of austenitic steel having a chromium content of 15% to 17% by weight, a manganese content of 12% to 16% by weight, and a molybdenum content of 0 to 4% by weight. The wire part (4) is formed to have an oval cross-section having an ovality O in the range from 0.4 to 0.9. At this time, the ovality O is measured as the ratio of the length (LQk) of the minor axis (Qk) to the length (LQg) of the major axis (Qg) of the cross-section. A method characterized by this. 12. The method according to 11 above, characterized in that the brush part (2) is stretched along the brush longitudinal axis (L) after twisting.

Claims

1. An interdental brush (1, 1') comprising a brush part (2) having two leg pieces (4A, 4B) of a wire part (4) twisted together with each other and brush filaments (5) sandwiched between the leg pieces (4A, 4B), wherein the wire part (4) is made of austenitic steel having a chromium content of 15% by weight to 17% by weight, a manganese content of 12% by weight to 16% by weight, and a molybdenum content of 0 to 4% by weight, has an oval cross-section before being twisted and has an oval cross-section having an ovality O in the range of 0.4 to 0.9 after being twisted, and the ovality O is measured as the ratio of the length (LQk) of the minor axis (Qk) of the cross-section to the length (LQ g) of the major axis (Qg), has an oval cross-section in which the ratio of the length (LH g) of the semi-major axis of the ellipse to the length (LH k) of the semi-minor axis of the ellipse is 1.4 to 1.6 before being twisted, the ratio of the maximum outer diameter (DD) of the wire part (4) to the maximum filament diameter (DF) of the brush filament (5) is between 4 and 4.6 characterized in that, interdental brush (1, 1').

2. The twisted leg pieces (4A, 4B) have a winding strip length (S) measured parallel to the brush longitudinal axis (L) that is less than 1.5 times the maximum outer diameter (DD) of the wire part (4), characterized in that, the interdental brush (1, 1') according to claim 1.

3. The depth (T) of the winding strip measured as the difference between the maximum outer diameter (DD) and the minimum inner diameter (Di) of the wire part (4) is less than 0.05 times to 0.2 times the maximum outer diameter (DD), characterized in that, the interdental brush (1, 1') according to claim 1.

4. The ratio of the length (LH g) of the semi-major axis of the ellipse to the length (LH k) of the semi-minor axis of the ellipse is 1.5 to 1.55, characterized in that, the interdental brush (1, 1') according to claim 1.

5. The number of brush filaments (5) per winding strip is greater than 10, characterized in that, the interdental brush (1, 1') according to claim 1.

6. The effective length (LN) of the brush filament (5) measured in the lateral direction with respect to the brush longitudinal axis between the outer contour of the twisted wire part (4) and the free end of the brush filament (5) is 3.8 times to 16 times the maximum outer diameter (DD) of the wire part (4), characterized in that, the interdental brush (1, 1') according to claim 1.

7. The interdental brush (1, 1') according to claim 1, characterized in that the free brush end (6) has a rounded portion, and the maximum diameter (DA) of the rounded portion is larger than the maximum outer diameter (DD) of the wire portion (4).

8. The interdental brush (1, 1') according to claim 1, characterized in that the austenitic steel has a nitrogen content of 0.5% by weight, a silicon content of 0.25% by weight, a carbon content of 0.11% by weight, and a nickel content of less than 0.05% by weight.

9. In a method of manufacturing an interdental brush (1, 1'), in which two leg pieces (4A, 4B) of a wire portion (4) are twisted together to produce a brush portion (2) of the interdental brush (1, 1'), and a brush filament (5) held between the leg pieces (4A, 4B) is tightened, using a wire portion (4) made of austenitic steel having a chromium content of 15% to 17% by weight, a manganese content of 12% to 16% by weight, and a molybdenum content of 0 to 4% by weight, forming the wire portion (4) so that it has an oval cross-section before twisting and an oval cross-section having an ovality O in the range from 0.4 to 0.9 after twisting, where the ovality O is measured as the ratio of the length (LQk) of the minor axis (Qk) to the length (LQ g) of the major axis (Qg) of the cross-section, the wire portion (4) having an elliptical cross-section with a ratio of the length (LH g) of the semi-major axis to the length (LH k) of the semi-minor axis of the ellipse being 1.4 to 1.6 before twisting, characterized in that the ratio of the maximum outer diameter (DD) of the wire portion (4) to the maximum filament diameter (DF) of the brush filament (5) is between 4 and 4.

6.

10. The method according to claim 9, characterized in that the brush portion (2) is stretched along the brush longitudinal axis (L) after twisting.

Images