KR100551626B1 - Toothbrush with a replaceable brush part - Google Patents

Abstract

The toothbrush of the present invention has a handle, a head of casing with at least one open side, a brush portion insertable on the open side and having a support and a hair facing, and on the support and inside the casing for fixing the brush portion, respectively. A locking device in the form of a protrusion and a recess in engagement with each other, wherein the casing has a cheek for supporting the support on its entire peripheral surface, and on the cheek there is provided a means for toollessly pushing the brush portion outward. In order to separate the "sealing" and "locking" functions, the inside of the casing cheeks and the periphery of the support have a completely flat walled sealing surface. have.

Description

Toothbrush with Replaceable Brush Part {TOOTHBRUSH WITH A REPLACEABLE BRUSH PART}

The present invention provides a handle, a head having a casing structure with at least one side open, a brush portion insertable in the opening portion and having a support and bristle facing, and a brush portion fixed thereto. And a locking device on the support and inside the casing, the casing having a side plate or a cheek that supports the support in the vicinity of the periphery above the head device for toollessly pushing the brush portion out from the rear of the head. It is about.

In the brushes known from US 403 350, US 1 148 566, US 1 711 621, and US 2 326 632, brush portions with bristle faces are continuously inserted into the actual brush body. This often occurs for manufacturing reasons, in particular when it is not possible to connect the bristle bundle directly to the brush body, for example by heat treatment such as welding, forming or the like. There is known a structure that can separate the brush part from the brush body and replace it with another brush part (GB 1932/1910). Such known structures may not be suitable or only insufficiently suitable for application to a toothbrush.

Toothbrushes are needed much more often than other types of brushes. The reason is that for proper oral hygiene, it must be used frequently (three times a day), which causes it to wear out quickly. In addition, even if relatively small wear has occurred, which may still be available in other brushes, these toothbrushes should always be replaced to obtain the optimum effect.

Due to high toothbrush consumption, about 1.5 million are consumed per year in Germany, and there is an increasing problem regarding the treatment and protection of resources. The material to be treated accordingly, even in the case of 100% recycling, cannot be processed into the same product because the recycled material does not meet the high quality requirements essential to the bristle material of the toothbrush. Known brushes with replaceable brush parts are basically capable of replacing only the brush parts after they have been worn out, but this problem has never been highlighted on the surface, such as cleaning brushes, body brushes, and cosmetic brushes. In the same case, it is relatively insignificant because the service life is much longer and the ratio of the unusable material to the still unusable material is not uneven as in the case of the toothbrush.

After all, the special feature of toothbrushes is that they can be used by people of all ages and all levels of education, so that brush parts can be replaced in a very simple manner and with little force, while at the same time being able to be sufficiently tightly combined. Should be considered.

There are basically two systems on the market today. In the case of the so-called replacement head brush (EP 0 199 849 B1, DE 94 20 405 U1), the entire head with bristles is detachably fixed to the handle. The locking fastening means is located on the shoulder of the handle and the head substantially transverse to the longitudinal axis of the handle, and is engaged by assembling the head and the handle in the longitudinal direction. Conversely, these two parts can be separated by pulling them apart from one another in the longitudinal direction. This replacement head brush is satisfactory in terms of use or hygiene. However, the plastic part of the head that is discarded when the bristles wear out is still a part that cannot be ignored. Another drawback is that the fastening means is located at the transition between the head and the handle, i.e. at the point where the bending force in use is greatest. The toothbrush is, in exactly this part, weakened due to the structural aspect of the fixing device. For use reasons, this problem is particularly acute in that it is desirable to have a narrow, optionally elastic neck between the handle and the head, which should not be equipped with a replacement head brush. Thus, a replacement head brush has already been proposed in which the head is locked to a thin neck on a thick handle. In this way, the advantages of use have been substantially maintained, but there is a cost problem that a large amount of plastic is wasted. All replacement head brushes also carry the risk of serious injury to the oral cavity if the locking system is improperly locked or broken during use.

In another known system to which the toothbrush according to the preamble of claim 1 belongs, the bristles are fixed to a support in the form of a thin plate, the brush part being replaceably fixed to a head such as a frame or a casing (DE 30 38 895, 37 24 640). The support is provided with a ledge, such as a ledge, on the surface surrounding it, and the casing is provided with a corresponding channel-shaped recess. The back of the support is provided with a pin that engages a hole in the bottom of the casing to form a pressing surface exposed on the back of the head. The support is fixed to the head and can be detached by pressing a pin. When the bristles are worn, the plastic parts to be replaced are reduced to a minimum, and the replaceable brush parts can be manufactured inexpensively because only a small amount of material is used. However, when compared with replacement head brushes, hygiene and structural problems arise. The gaps necessarily present between the supports and the cheek of the casing are only insufficiently dried, causing dust to accumulate and bacteria to collect. This applies somewhat to the total gap between the head and the support.

Thus, on the bristle side of the support, an elastic peripheral rim was provided, the rear portion of which was sealingly engaged with the front of the casing cheek (DE 37 24 640 C2). This presupposes a corresponding tension and thus a corresponding high locking force to pull the support into the casing. This makes it more difficult to insert and detach the brush part. Since the locking is self-closing, the locking means must have a correspondingly large volume characteristic, which requires a significant wall thickness on the head. In more complex structures (DE 296 00 398 U1), the support and the casing On all sealing faces in between, elastic flat yarns are provided which simultaneously hold the brush portion by corresponding high pretension. This pretension must be completely absorbed by the casing cheeks which inevitably widen in a short time and no longer securely secure the brush part.

Another proposal to provide a locking ledge in a divided manner on the periphery of the support (DE 91 09 625 U1, DE 44 34 617 Al) reduces the sealing of the gap, since the locking ledge and the recess are located in the sealing surface, Very precise design should be used to ensure that the sealing surfaces are fitted snugly and securely locked. The injection molded parts used for the heads and handles and the inexpensive plastic make it nearly impossible to design precisely like this. In addition, the casing cheeks are always subject to elastic pretension due to the locking force. Since plastic has no resistance to creep under tension (cold flow), the tension in casing cheeks decreases very quickly, resulting in a widening of the gap between the cheek and the support, which facilitates the ingress of dust and bacteria. Become. Since the fatigue of the plastic and thus the increase in tolerance are hardly noticeable to the user, the locking means must be broken when wiping the teeth. If the brush part is separated during use, it can damage the mouth and gums as well.

A very stable and durable connection between the brush part and the head is shown in the known toothbrush (DE 41 04 314 A1), where two mutual V-shaped ridges on the back of the support, across the entire support length Is formed. They are open outwardly in a V-shape on the head and engage in slots through the entire length of its longitudinal axis. The ledges must be deformed inwards towards each other so that they can pass through the narrowest cross section of the V-shaped slot during insertion and then expand within the slot. In this way, the elastically deformed portion of the locking engagement portion is placed in the replacement portion, where material fatigue is less important. The deformation force on the ledge needed to create or break the lock engagement is large enough that the brush portion can be pressed or tipped open by a specially adapted tool. The need for this special tool not only imposes a correspondingly high system cost on the consumer, but also prejudice when selling the system in the market. This also applies in that the need for injury prevention, i.e., does not meet the soft shape of the back of the brush. In addition, these toothbrushes are also disadvantageous in terms of hygiene because the slots and ledges form a large number of gaps where dirt, toothpaste residues and bacteria can accumulate.

The latter disadvantage is somewhat reduced in other known constructions (US 4 543 679), in which a long pin is provided at the position of the ledge, which fits into a concave widening hole outwardly on the underside of the casing.

1 is a partial plan view of the back of a toothbrush.

FIG. 2 is a view of FIG. 3 taken along II-II. FIG.

3 is a plan view of the bristle surface;

4 is a view taken along the line IV-IV of FIG. 3;

5 is a longitudinal cross-sectional view of another embodiment of a toothbrush head without a brush portion.

6 is a bottom view of the head.

7 is a cross-sectional view corresponding to FIG. 5 of another embodiment.

8 is a bottom view of the brush head according to FIG. 7.

9 is a longitudinal sectional view of the brush head in another embodiment.

10 is a bottom view of the head according to FIG. 9;

11 is a longitudinal sectional view of a head having another structure.

12 is a bottom view of the head according to FIG. 11;

13 is a longitudinal sectional view of the brush head with the modified structure.

14 is a bottom view of the head according to FIG. 13;

15 to 22 are cross-sectional views of the brush head according to FIG. 4 with casings and brush partial supports of different constructions.

The object of the present invention is to provide a toothbrush of the type described above, in particular in which hygiene requirements are met and the use properties are improved.

According to the invention, the cheeks of the casing and the interconnected surfaces around the support consist of a completely smooth walled sealing surface, the locking device being positioned inwardly positioned relative to the sealing surface and the back of the casing bottom and the support facing it. The above problem is solved by having a resilient detent located in the space between.

An important advantage of the present invention is that the "sealing" and "locking" functions are structurally separated. The smooth periphery on the support and the smooth contact surface of the cheeks are essential for sealing them completely satisfactorily to each other. If these surfaces have a slightly conical structure, this may help with this coupling. As a result of locking mechanisms such as resilient detents outside the sealing surface, the casing cheeks do not require locking and bearing forces, and consequently cold flow does not occur, thus ensuring a long sealing performance. Will be. While preventing toothpaste residues and the like from accumulating or penetrating, in a preferred manner, the toothbrush dries quickly after use, resulting in voids, voids, and the like, to prevent the accumulation of bacteria. Resilient detents allow functionally reliable locking while making replacement easier.

The outer contour of the toothbrush near the head ensures correct use, since the position lock is located only inside the casing between the base and the rear of the support, while the elastic detent is placed in an area where dimensions are not limited by other structural situations. Can be adjusted in an optimal manner, for example, rounded and soft contours are possible, thereby preventing the oral cavity from being damaged while administering oral hygiene. Therefore, it can be designed such that operational reliability is maintained for a long time. The thin entire casing cheek is not tensioned. Due to the placement of the locking device and the pressing surface for the release, the bristles are not released when they are not desired because the pressure on the bristles during use does not release the locking system, which is intentional and limited to the rear of the head for this purpose. This is because pressure must be applied. The ease of replacement of brush parts allows users to use such a system, especially since brush parts with bristles with different hardness characteristics and placements can be used.

In a preferred embodiment, the resilient detent protrudes inwardly on the bottom of the casing and engages with the depression in the back of the support.

In an advantageous embodiment, there is a through opening in the bottom of the casing forming the back of the brush head, the wall of the opening extending at least partially inward in the direction of the resilient detent, and the support having a pin coupled to the through opening. And the front surface of the pin forms an exposed pressing surface for pressing the brush portion or acts together with the pressing surface on the casing.

In this embodiment, the through opening with the wall in the form of a sleeve has several functions. Firstly, the pins on the support can be guided, and secondly, at least a portion of the wall can be used to construct an elastic detent for positioning and securing the support. Finally, the through opening makes it possible to create a pressing surface on the back of the head. The pressing face is formed either directly by a pin passing through the through opening, ie by the exposed front side of the pin, or by a casing portion which seals the through opening at the rear of the head so that the pressure applied to the pressing face is passed through the casing. May be configured to act on the pin.

When the pin is guided on the wall of the through opening, the perimeter of the pin is provided with a depression in which the casing is detented from the outside.

If the exposed front of the pin forms a pressing surface, the pressing surface projects slightly over the contour of the casing on the back of the head so that the function can be indicated and pressure to release the locking system can be applied without difficulty.

Apart from the advantages of use, the embodiment described above has the advantage that the toothbrush comprises only two components, a handle with a head forming a casing, and a brush portion with a support and bristles.

Although somewhat more complicated in manufacturing, the same use-benefit embodiment is characterized in that the pin is located in the through opening at a distance from the wall of the through opening, and the support has an elastic detent and an outwardly engaging depression. There is an embodiment.

Preferably, the through opening at the rear of the head is preferably sealed by a pressing plate having the front face of the pin fitted therein and forming a pressing surface.

This structure has the advantage that the back of the toothbrush head is completely sealed, so that there is no sealing problem that results in a disadvantage.

In this embodiment, the pressing plate forming the pressing surface may be made of a material such as rubber, for example elastomer, and inserted into the opening edge of the through opening, for example, fixed by being fitted to the wall of the opening. Or may be injection molded on the opening in an in-mould process. The pressure plate is at least partially elastically deformable so that the necessary space for separating the support when the pressure is applied on the pressure plate is secured. Therefore, pressure is applied to the pressing plate on the pin, which moves in the direction in which the support is pressed and releases the detent.

Alternatively, the pressure plate may be made integral with the head and connected to the remaining casing in a resilient manner by the thin thickness of the head in this region, or by a flexible wall portion.

If the pressing plate is an elastic part of the head, the detent may be formed on the underside of the casing to the side of the pressing plate, and by pressing the pressing surface the detent can be released from the locking position in which the support is held between the pressing plate and the detent, to release the support. have.

The elastic properties of the detent can be obtained with virtually any plastic material, depending on the length of the detent, while the casing is dimensionally stable. In addition, the elastic properties can be obtained by a thin wall portion on the back side of the head so that the pressing surface forming part of the casing can be limitedly moved. In addition, such a resilient wall portion may be formed at the beginning of the detent on the casing, in order to generate the movement and expansion of the detent by applying pressure on the pressing surface so that the support is separated from the locking system and falls down. have.

The cheeks are coupled to the support in whole or in part on the surface, and the coupling where the support and the outer surface of the cheeks are connected at the same height is advantageous because no edges or depressions are generated.

Alternatively, the support can be flush with the outside of the cheek in combination with the front of the cheek. This forms an additional sealing surface. This structure also does not form recesses or steps where dust can sit.

In another embodiment, the support has a peripheral edge on the opposite side of the bristle face, by which the support engages the cheeks externally.

This embodiment has the advantage that the support forms a sealed surface not only in the area of the bristle face but also on the side of the head.

Contact with the gums when using a toothbrush is primarily the side area of the head, so smoothing this area prevents the risk of gum damage. In addition, the area adjacent to the bristle surface is particularly likely to stick to dust due to the toothpaste applied to the bristle surface, and bacteria may also accumulate. The above problems are avoided due to the smooth structure without gaps or recesses in the edges of the support, which are combined with the support and the cheek.

Both of the embodiments described above have the advantage of providing maximum bristles on the support in the contour of a given head.

By the casing structure of the present invention, the support may be made of elastomer, and the support may be sealed against the cheek, and a sealing lip may be used for such sealing. The casing structure of the present invention allows the cheek to tighten and squeeze the support of the elastomer in a frame-like manner. In the sealing surface area, an additional increase in frictional force occurs to reliably prevent the occurrence of gaps. The ends of the bristles positioned on the supports are elastically supported.

Finally, the push face may be visually distinguished from the rest of the casing by the surface design so that the user knows the function of the push face. This visual distinction can be made by different contours, using different materials, different colorings, and the like.

At least in the region of the cheeks, the casing may have a soft and elastic cover on its exterior to protect the mucosa. It can additionally cover the front of the cheek and its inner edge can seal sealingly with the peripheral surface of the support.

In the case of the structure of the invention, the structure of the invention can be made thinner than the conventional structure, since the locking device is no longer located on the casing cheek, but instead the casing cheek only serves as a guide and seal. Conversely, the support surface and consequently the number of bristles or bristles can be increased or expanded.

The invention is explained in more detail hereinafter with the accompanying drawings.

The toothbrush shown in FIGS. 1 to 3 has a long handle 1, partly cut off, and a support 4 having a head 2 and a bristle face 5 of an individual bristle bundle 6. A replaceable brush part 3. The head 2 of the toothbrush consists of a casing 7 in which a brush part 3 with a support 4 is inserted in a replaceable manner.

In all embodiments the casing 7 has a peripheral side plate or cheek 8 at the side boundary, which is sealed by the wall 9 towards the handle 1 (FIGS. 2 and 4). Together with the wall 9, the peripheral cheek 8 forms a rigid frame shape which, together with the rear face 10, forms a cavity which opens downward to accommodate the support.

In the embodiment according to FIGS. 1 to 4, the casing also has a through opening 11, the wall of which is formed of an elastic detent, at least part of which protrudes into the cavity. The planar support 4 on the side of the bristle surface 5 has a plate-shaped portion 13 with a contour that matches the contour formed inside the cheek 8 and the wall 9, and the through opening 11. It includes a pin 14 that is guided through the interior. The pin 14 has an exposed front face that slightly protrudes over the back side 10 of the casing 7, which forms the pressing face 15. As shown in FIG. 1, these pressing faces can be visually distinguished and can optionally vary the surface contour.

An elastic detent 12 in the region of the through opening 11 is engaged with the depression 16 on the correspondingly formed support 4, in this embodiment the depression into plate-shaped portion 13. It is moved inward in the transition region and is located around the pin 14.

From the use position shown in Figs. 2 and 4, the brush part 3 applies a pressure to the pressing surface 15 acting in the direction of the bristle surface using a finger so that the elastic detent 12 retreats outward. In such a way that the brush part 3 falls down, it can be easily replaced with a new brush part.

The bristle bundle 6 of the brush part 3 can be secured to the support 4 in several different ways, for example in a pre-made hole by means of an attachment device or adhesive, which can be joined to the support or A thick portion 17 may be provided and molded to the support.

In the embodiment of FIGS. 5 and 6, the through opening 11 is asymmetrical elliptical and the wall in the cavity of the casing 7 extends towards the elastic detent 12 forming a peripheral ring. The embodiments of FIGS. 7 and 8 differ from the embodiments of FIGS. 5 and 6 only in that the through opening 11 and the resilient detent 12 are circular.

In the embodiment shown in FIGS. 9-14, only a portion of the wall of the through opening 11 protrudes towards the cavity to form an elastic detent 12. 9 and 10, a detent 12 having a U-shape is shown, and in the embodiment according to FIGS. 11 and 12, the through opening 11 on the narrow side facing each other has an arcuate two resilient opening. A detent 12 is formed, and the walls of the through opening on the longitudinal side in Figs. 13 and 14 extend toward the opposing detent.

15 to 22 show casings and supports and locking devices of different constructions. In the embodiment of FIG. 15, the support 4 is the plate-shaped part as well as the casing forming the head, as in the embodiment of FIG. 13 and pin 14. Unlike the embodiment of FIG. 4, the plate-shaped portion 13 of the support 4 forms the lower end of the head and the front face 18 of the cheek 8 is the plate-shaped portion 13 of the support 4. To form a support for the top of the). On the other hand, the support 4 ends at the same height as the outside of the cheek 8 in its circumference.

In the embodiment of FIG. 16, the plate-shaped portion 13 of the support 4 has a stepped inward step on its top and the front face 18 of the cheek 8 engages with this end. The recessed part of the plate-shaped part 13 is guided inside the cheek 8. In this embodiment, a cover 28 of elastomer is inserted outside the cheek 8 to protect the mucosa. This cover 28 can protrude beyond the front of the cheek 8 and is sealingly engaged on the periphery of the plate-shaped portion 13.

Unlike FIG. 16, FIG. 17 shows a support 4 having a plate-shaped portion 13, which is installed and guided at the inner end 19 of the head cheek 8.

In the embodiment according to FIG. 18, the support 4 has an upwardly rim 20 on the plate-shaped portion 13, with the cheek 8 having a corresponding end within the rim. Are combined. 19 shows a structure in which the outer endless cheek 8 is coupled behind the upside edge 20 of the support 4.

In the embodiment according to FIG. 20, the resilient detent 12 is facing outwards and the support 4 is provided with an upwardly protruding stud 21 which forms a locking depression 16. This depression engages outwardly with the detent 12. In this embodiment, the pin 14 passes through the through opening 11 at a wider distance from the wall. The through opening 11 is closed at its top by a pressing plate 22 which forms the pressing surface 15, which is fixed or shaped to the wall of the through opening 11 in (23) of the drawing. The pressing plate 22 has a rubbery structure. The bottom surface of the pressing plate 22 is engaged with the front surface of the pin 14. When pressure is applied to the pressure plate 22, the pin 14 moves down. The stud 21 fixed on the support moves the resilient detent 12 inwards to free the support 4 with the bristle bundles.

In the embodiment according to FIG. 21, the support 4 has a plate-shaped portion 13 and a shorter pin 24 than in the previous embodiment, the circumference of the pin for the elastic detent 12. The locking depression 16 is formed. The pressing plate 25 is provided in the center of the casing 7. This press plate is connected to the casing by a thin wall of resilient wall portion 26. A resilient detent is formed just below the wall portion 26, which in turn is connected to the cheek 8 of the casing 7 by the resilient wall portion 27. In the case of applying pressure to the pressure plate 25, the detent 12 is spread outwards by the resilient wall portions 26, 27 (see FIG. 22), so that the support 4 with the bristle bundle 6 is provided. Free and fall down.

Combining the figures, in all embodiments, the joining interior of the cheek 8 and the peripheral surface of the support 13 are smooth and slightly conical tapered inwards, the elastic detent 12 and the locking depression 16. The locking device consisting of) is moved inward with respect to the cheek and the support.

According to the invention, the plastic part to be replaced is minimal when the bristles of the toothbrush are worn out, the locking mechanism is not released during use of the toothbrush, the brush is easy to replace, and the gap between the replacement part and the toothbrush head is minimal This has the advantage of less penetration of toothpaste residues and dust into the gaps, so that the amount of industrial waste can be reduced, and a good toothbrush can be provided for design hygiene.

Claims (22)

A head consisting of a handle, a casing with at least one side open, a brush portion insertable in the open side and having a support and bristle surface, and positioned on the inside of the casing and on the support to secure the brush portion With locking device, The casing includes a toothbrush having a support in its peripheral area and a device for pushing the brush portion out of the rear of the head without tools. The opposing surfaces on the cheek 8 of the casing 7 and on the periphery of the support 4 consist of completely smooth wall sealing surfaces, The locking device has an elastic detent 12 moved inward with respect to the sealing surfaces, The resilient detent is located in the space between the bottom of the casing (7) and the back of the support (4) facing it. The method of claim 1, The resilient detent (12) is in the form of protruding inward from the bottom of the casing (7), the toothbrush, characterized in that coupled with the depression formed on the back of the support (4). The method according to claim 1 or 2, The underside of the casing 7 has a through opening 11, the wall of the through opening extending at least partially inward in the direction of the resilient detent 12, The support 4 has a pin 14 that engages with the through opening 11, the front face of the pin forming an exposed pressing surface 15 for pressing out the brush part 3 or casing 7. Toothbrush acts together with the pressing plates (22, 25). The method of claim 3, wherein The toothbrush (14) is guided on the wall of the through opening (11) and has a recess (12) around it. The method of claim 3, wherein Toothbrush, characterized in that the pin (14) with an exposed front face slightly protrudes over the contour of the casing (7) on the back (10) of the head (2). The method of claim 3, wherein The pin 14 is located in the through opening at a distance from the wall of the through opening, and the support 4 has a depression 16 which engages outward onto the resilient detent 12. toothbrush. The method of claim 3, wherein The through opening 11 is sealed on the rear surface 10 of the head 2 by pressing plates 22 and 25 forming the pressing surface, and the pressing plate is engaged with the front surface of the pin 14 from the inside. Toothbrush made. The method of claim 7, wherein The pressing plate (25) is characterized in that it is connected to the remaining casing (7) by a flexible wall portion (26). The method of claim 7, wherein The pressing plate 25 is a toothbrush, characterized in that configured to be flexible and resilient. The method of claim 7, wherein The pressing plate 25 is a toothbrush, characterized in that the integral part of the head. The method of claim 7, wherein Toothbrush plate 22 is made of a resilient material. The method of claim 11, The press plate (22) is a toothbrush, characterized in that the injection molding with the head in-mold process. The method of claim 7, wherein The pressing plate 22 is a toothbrush, which is manufactured by a separate injection molding is fixed to the head (2). The method of claim 7, wherein The detent 12 is formed along the sides of the detent plates 22 and 25 on the casing 7, and is pressed in the detent position of the locking position where the supports 4 are fixed between the detents by pressing on the detent plates 25. Toothbrushes, characterized in that the detent is opened to the outside, the support (4) is separated. The method of claim 1, The toothbrush (8) of the casing (7) is characterized in that it is coupled to the support (4) partially or entirely from the outside. The method of claim 1, Toothbrush, characterized in that the back of the support (4) is coupled to the front (18) of the cheek 8 and finished to the same height as the outside of the cheek. The method of claim 1, Toothbrush is characterized in that a peripheral edge (20) is provided on the back of the support (4), by which the support is coupled to the cheeks (8) from the outside. The method of claim 1, Toothbrush, characterized in that the support (4) is made of an elastomer that seals against the cheek (8). The method of claim 3, wherein The pressing surface (15) is characterized in that it is visually distinguished from the head (2) by the surface design. The method of claim 1, Tooth casing (7), characterized in that at least in the region of the cheek (8), a soft and resilient cover is provided from the outside to protect the mucous membrane. The method of claim 20, The cover covers the front face of the cheek (8) and is characterized in that it sealingly engages with the support (4) in this area. The method of claim 7, wherein Toothbrush, characterized in that the pressing plate 22 is made of an elastomer.