Mouth guards are generally used by people who engage in contact sports, such as rugby, boxing and martial arts.

However, mouth guards may also be advantageous for any person who requires protection of the upper jaw region.

A number of sporting events are now televised therefore sponsorship has had a considerable impact. Sports participants wear badges and/or logos to indicate their approval of a specific brand or to show allegiance to a particular club or country. Such sponsorship and/or logos are typically found on shirts, boots, shorts etc. In order to maximise such advertising the application of a logo to a mouth guard would be advantageous.

Mouth guards having logos thereon have previously been manufactured using a transfer or sticker process, whereby the entire mouth guard is laminated subsequent to the transfer or sticker being applied. The use of a laminate is disadvantageous as the laminate tends to wear off during use. In addition the logo tends to fade and/or distort.

It is therefore an aim of the present invention to alleviate at least some of the disadvantages identified above.

It is a further aim of the present invention to provide a mouth guard which provides increased protection over traditional mouth guards.

It is yet a further aim of the present invention to provide

a mouth guard having indicia thereon and a method of making such a mouth guard.

Therefore, according to a first aspect of the present invention, there is provided a mouth-guard having a substantially U-shaped trough comprising a first material, the trough having at least one internal cavity portion which is substantially filed with a second material.

It is particularly preferred that the internal cavity portion substantially does not come into contact with an external portion of the mouth-guard.

It is particularly preferred that the trough comprises an outer wall and an inner wall connected by a base portion.

Preferably, the mouth guard is of a thermoplastics material such as an ethylene vinyl acetate copolymer. Although it is envisaged that any thermoplastic material may be used according to the present invention. The mouth guard may also be manufactured from a biodegradable material.

According to a first embodiment, it is particularly preferred that the second material comprises a shock absorbing material.

The shock-absorbing material may be a foam, gel, liquid or the like. It is also envisaged that the shock absorbing material is substantially the same material as the first material but has a different viscosity (preferably of a lower viscosity). The second material is preferably inert and advantageously bonds to the first material. Both the second material and the first material should not be toxic or harmful to humans. In a particularly preferred embodiment the second material comprises ethyl vinyl

acetate copolymer having a lower viscosity than the first material. The second material is preferably resilient. It is also envisaged that the shock-absorbing material may be air, or any other inert or non-toxic gas.

Advantageously, the shock absorbing material provides the advantage that increased protection is afforded to the anterior region of a persons teeth.

According to a second embodiment, it is also envisaged that the second material is capable of illuminating at least a portion of the mouth guard. Alternatively, the second material may be preferably a material of a different colour such that the different colour can be visible to the outside of the mouth guard.

It is particularly preferred that the internal cavity portion extends substantially along the trough which is arranged to cover the anterior portion (and preferably the posterior portion) of a persons teeth, when the mouth-guard is being worn by the end user.

However, it is envisaged that the internal cavity portion may extend along the length of the outer wall and may, if desired extend to the base portion and/or the inner wall.

It is further preferred that the mouth-guard comprises a material having antibacterial properties. Therefore, according to a further aspect of the present invention, there is provided a mouth guard which is manufactured from a material having antibacterial properties.

The mouth guard may of the type commonly known as a"boil- in-the-bag"mouth guard wherein the trough has an internal surface which is substantially flat (this type is typically

provided unshaped to the user who subsequently heats the unshaped mouth guard, in for example hot water, and shapes the mouth guard using their fingers, tongue and/or biting pressure). Alternatively, the mouth guard may be of the type which is individually manufactured according to the end users personal morphology. A dental technician typically prepares such individually manufactured mouth- guards.

The present invention is therefore further extended to a method of manufacturing a mouth guard substantially as described herein before. The method comprises a dual injection moulding process, whereby the first material is injected into a die using a first injection tool, and second material is injected into the die using a second injection tool so as to form an internal cavity portion comprising the second material.

It is therefore further envisaged that the mouth-guard may include a display panel, such as an LCD screen.

According to yet a further aspect of the present invention, there is provided a partially preformed mouth guard comprising a substantially U-shaped trough, the trough has. an internal surface which is shaped and dimensioned to substantially correspond to the contours of anatomical carving and structure.

It is further preferred that the internal surface is further shaped and contoured to correspond to the muscle contour of an average persons upper jaw.

Desirably, the trough has a thickness of approximately 3 to 6 mm (preferably 5mm).

Prior art"boil-in-the-bag"mouth guards typically have a uniform thickness of about 3mm. When the"boil-in-the-bag" mouth guards are softened (for example in hot water) and placed in a persons mouth to be formed, the user shapes the mouth guard using the tongue, fingers and/or biting actions. The mouth guard therefore deforms, especially around the occlusion section and the anterior and posterior areas; the distortion may result in the mouth guard's thickness being reduced to about 1mm in these areas that dramatically reduces the protection afforded to the user.

Mouth-guards according to the present invention having preformed anatomical structures and preferably preformed muscle contour regions, substantially reduce the distortion of the mouth guard during the heating and shaping process of the user. This is achieved as the preformed internal surface requires less moulding by the user (for example by being heated in hot water and subsequently being shaped in the mouth) in order to correspond to the end users own personal morphology.

The preformed mouth guard is preferably a"boil-in-the-bag" type mouth guard substantially as described hereinbefore.

The mouth guard may comprise an internal cavity portion substantially described hereinbefore with reference to the first aspect of the present invention.

According to a further aspect of the present invention, there is provided a mouth guard having thereon an indicia which has been applied using a pad printing process.

According to a further aspect of the present invention, there is provided a (preferably injection moulded) mouth guard comprising a substantially U-shaped trough wherein

the trough has at least one indicia thereon which has been applied by a pad printing process.

According to yet a further aspect of the present invention, there is provided a method of manufacturing a mouth guard having indicia thereon, which method includes providing an injection moulded mouth guard, and applying a (preferably coloured) indicia to the mouth guard by a pad printing process.

Preferably, contaminants such as dust and/or polymer residue, is removed from the surface of the injection moulded mouth guard prior to application of the indicia.

The contaminants are preferably removed by use of a swab typically impregnated with alcohol.

It is envisaged that the mouth guard is moulded in a die which has a portion corresponding to the indicia such that the resultant moulded mouth guard has an integral image of the indicia on a surface thereof.

It is particularly preferred that the integral indicia is raised from the surface of the mouth guard by an amount of no more than about 0.25 microns (preferably no more than about 0.15 microns). Alternatively, the indicia may be depressed by a similar amount.

Preferably, the pad printing process includes applying (preferably by stamping) a (preferably food approved) colour or pigment to the mouth guard.

The pad printed indicia may comprise one or more colours.

For example the indicia may be a flag, a trademark or a pictorial representation.

According to yet a further aspect of the present invention, there is provided a method of applying an indicia to a mouth-guard, which method includes: indenting at least a portion of the mouth-guard with a shape which is substantially the outline of the indicia so as to form an indented portion; positioning a portion of sheet material having substantially the same shape as the indented portion over the indented portion; and heating the mouth-guard substantially in the region of the indented portion and/or the sheet material such that the sheet material fuses to the mouth-guard substantially in the region of the indented portion.

It is particularly preferred that the mouth-guard and the sheet material are substantially of the same material (preferably of thermoplastics material).

Typically the sheet material and the mouth-guard are of a different colour.

The indicia is typically cut from the material by use of a laser, however, it is envisaged that the indicia are cut from a larger sheet by use of a blade (which may be manual or mechanical).

The mouth-guard may be a custom made mouth-guard which is individually manufactured in accordance with the end uses morphology. Alternatively, the mouth-guard may be one of the mouth-guards according to an earlier aspect of the present invention substantially as described hereinbefore.

The present invention will now be further described, with reference to the accompanying drawings which are given by way of example only.

FIGURE 1 represents view from above of the mouth guard according to the present invention; FIGURE 2 represents an underside view of the mouth guard of Figure 1 ; FIGURE 3 represents a cross-section along the line AA of Figure 1 ; FIGURE 4 represents a cross-sectional or view of the mouth guard of the present invention; FIGURE 5 represents a front-view of the mouth guard according to a further aspect of the present invention; and FIGURE 6 represents the mouth guard according to the present invention in use.

Referring to Figures 1 to 4, where like numerals have been used to identify like parts, there is provided a mouth guard generally identified by the numeral 1. The mouth guard comprises a generally U-shaped ethylene vinyl acetate copolymer channel, which is formed by injection moulding..

The internal surfaces of the channel 2 is shaped and dimensioned to correspond with the contours of anatomical carving and structure in an average persons mouth. The underside of the mouth guard 1 has indentations therein which correspond to the general contours of anatomical carvings of the lower jaw.

Referring to Figure 3 and 4, the mouth guard 1 includes an internal cavity portion 5, which is substantially filled with a shock absorbing gel-like material 6. In order to shape the mouth-guard so as to conform to the end users

personal morphology, the preformed mouth-guard is immersed in hot water until the ethylene vinyl acetate copolymer has softened. The mouth-guard is subsequently placed in position in the end users mouth so that the end user can mould the mouth-guard (by biting, use of fingers etc) to their own personal morphology. The subsequently moulded mouth-guard according to the invention does not thin in the bite-region'compared to prior art boil in the bag' mouth-guards, as the mouth-guard according to the present invention doesn't need to be shaped as much when compared to the prior art mouth-guards.

In use, the mouth guard protects the upper jaw if a person wearing the mouth guard is hit around the jaw region being protected by the mouth-guard 1, the force of impact is dispersed.

Referring to Figure 5 there is shown a front view of a mouth guard 1 having a logo 2 thereon which has been applied by a pad printing process.

Referring to Figure 6 is shown a mouth 8 and a mouth guard 1 which is shown in outline only.