The brush head produced in accordance with the inven- tion is particularly suitable for the so-called pre¬ ventive dental care which includes cleaning of the teeth and massage of the gums to prevent caries and infection of the gums, including paradentosis etc. The brush head produced according to the invention can be used both on the dentist's drill and on home -care devices such as, for example, battery-driven dental care equipment with rotating drive mechanisms.

The object of the invention is to provide a method of producing a brush head whereby it is both cheap and quick to produce the brush heads, and which in their production are provided with such a shape that they can effectively clean the teeth and massage the gums without in any way damaging the teeth or the gums. This object is achieved by producing the brush head as presented and characterized in claim 1. With just a few working operations and simple tools, one can produce a brush head so cheaply that it is possible to use the brush as a disposable brush which can be discarded after use, even though it is robust enough to be used repeatedly. The fact that it is disposable makes the brush particularly suitable for use in clinics, in that cleaning of the brush after use is avoided, whereas in the home-care of the teeth the same brush can be used innumerable times because it can be cleaned in the same way as a normal toothbrush, i.e. under running water.

The method according to the invention is effected

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chiefly as presented in claim 2, whereby a particul¬ arly cheap production of the brush is achieved by the use of one of the many usable synthetic materials which can be welded ultrasonically, and whereby the bottom plate and the bottom hole are produced in one operation while at the same time an effectice secur¬ ing of all the fibres is achieved. Depending on the material which is used, either one or several weld¬ ings are carried out in immediate succession.

A brush head with a very effective cleaning ability is achieved when it is produced as presented in claim 3. Moreover, it is possible in a simple way to pro¬ duce a brush head having a concave end with a rounded tip by mechanically machining the bundle of fibres, for example while securing the the brush head in the bottom plate and the bottom hole, in that during the machining the brush head rotates around an axis -through the bottom hole.

By producing the brush head as presented in claim 4, a good joining together of the fibres in the centre of the brush head is achieved, the result being a firm and suitably stiff brush head which can be held precisely and securely on an ordinary clinical drill or a battery-driven home-care device.

By producing the brush head as presented in claim 5, a cup-formed brush is obtained with only one further operation.

The invention also relates to a brush for dental care, said brush being produced in accordance with the method.

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There is a need for a brush for the cleaning of the teeth and massage of the gums which can be mounted on the dentist's clinical drill or on a home-care device such as battery-driven dental care equipment. During rotation, the brush must be capable of cleaning the teeth and massaging the gums without the rotational movement in any way causing damage to the teeth or gums. This is achieved by a brush as presented in claim 6.

For various cleaning or massaging functions, the ac¬ tive end of the brush can be shaped as presented in claim 7 or 8.

Although the brush produced in accordance with the invention can be used for other functions, for exam¬ ple polishing of the nails and the like, it is pro¬ duced and shaped especially for the cleaning of teeth and massage of the gums, in that the brush's special shapes make this possible without the subsequent dam¬ age which is known form other similar devices.

The method will now be described with reference to the drawing, where the individual figures in sequence show a preferred method of producing a brush head in accordance with the invention, and a tool for use in the further machining of a brush head, and where

fig. 1 shows a bundle of fibres and a tool for forming the bottom plate and the bottom hole in the brush head,

fig-- 2 shows the fibre piece cut off and with bottom plate,

fig. 3 shows a plane section along the line Ill-Ill in fig. 2,

fig. 4 shows the finished brush head according to the invention, and

fig. 5 shows a section along the line V-V in the finished brush head shown in fig. 4, 0 fig. 6 shows a second embodiment of a finished brush head according to the invention,

fig. 7 shows a,plane section along the line 5 VII-vTI in the brush head shown in fig.

6, and

fig. 8 shows a holding and cutting tool for use in the production of the brush 0 shown in figs. 6 & 7.

In fig. 1 of the drawing is seen a bundle of fibres 4 consisting of many parallel, thin threads or fibres of a suitable material, for example one of the heat-weld- 5 able nylon materials such as polyamide or similar suitable material. For instance, a nylon fibre mater¬ ial with the designation DuPont Code 0900 MA can be used, in which case there are used 1000-50Q0 fibres in bundle 4. Q

Opposite the bundle of fibres is shown a tool 1 with a protruding tip or mandrel 3 and a circular recess 2 around the protruding tip 3. The fibre bundle 4 is held together by a suitable tool or a holster which

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surrounds the bundle 4 and holds the fibres together. The fibre bundle is mainly circular in cross section. The end of the fibre bundle is pressed against the tool 1 or, vice versa, the tool is pressed against the end of the fibre bundle, in that the tool is heated or has been heated so that the end of the fibre bundle is melted and welded to a bottom plate 6, as shown in fig 2. The welding together can be effected by any means of heating the tool 1, but ul- trasonic heating is to be preferred, in that the tool 1 is provided directly with a built-in ultrasonic transducer with a frequency of, for example, approx. 40,000 Hz, thus providing a simple manner by which the heating and therewith the welding together can be controlled. At the same time, a bottom hole 7 is formed by the mandrel or tip 3, see fig. 3, in that the walls of the hole ^" are also formed by fibres which have been melted together, so that all fibres in the bundle are now secured, either by the bottom plate 6 or the walls or the bottom of the hole 7. A suitable piece 5 is then cut from the bundle 4, see figs. 2 and 3, which is then again ready for the production of a bottom plate, possibly with bottom hole.

Naturally, the welding-together process depends on which material is used for the brush head. If the ma¬ terial mentioned above is used, it has proved advant¬ ageous to carry out two weldings separated by a short period of time for cooling. The fibre bundle is first joined together lightly, after which the actual weld¬ ing is effected. The result is a firm and secure join¬ ing together of all the threads without the bottom plate becoming too thick, which gives too stiff a brush.

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When all of the fibres are secured by the bottom plate 6 or the walls or bottom of the hole 7, the brush part 8 of the brush head can be given its final machining. This machining is preferably carried out with mechanical tools which cut or grind the brush part 8 to provide a concave end, the tip of which is rounded so that it can be introduced between the teeth and into the space between the teeth and the gums for cleaning and massaging without damaging neither the teeth nor the gums.

The bootom hole 7 is so formed that it almost reach¬ es to the area where the concave end begins, whereby all the fibres are firmly secured and held so that they still lie parallel with each other and with the bottom hole 7. The wall of the bottom hole is partly flexible, thus enabling the brush head to be mounted on many different kinds of rotating tools, merely providing that these have a spindle or mandrel which fits in the bottom hole 7.

The brush head can also be machined so that it is provided with a cup-shaped form, as shown in figs. 6 and 7, in that the central part 9 of the brush head is removed by being cut off, the result being that the brush head is left with a circular edge 10. This brush is particularly suitable for cleaning the sur¬ faces and the sides of the teeth.

A tool for use in the cutting out of the central bot¬ tom hole 9 is shown in fig. 8. A holder 12 secures the produced brush 5 so that the free brush ends point towards an ancillary tool 11. When the holder feeds the brush head 5 in the direction of the arrow

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14 towards the ancillary tool 11, which is circular in form, only the central part 15 will pass through the hole in the ancillary tool 11, where said central part 15 is cut off with a knife 13. The brush head is thus provided with a bottom hole 9 as shown in figs. 6 and 7

For certain tools used in dental treatment, it is not necessary for the brush head to be provided with a bottom hole 7. In such cases it is sufficient to use an even more simple tool 1, in that one can use a tool without the protruding tip or mandrel 3 shown in fig. 1.