AU2003273623B2 - Dental care product - Google Patents

Description

WO 2004/039282 PCTiAU2003!001411 DENTAL CARE PRODUCT This product relates to a method and a product for inhibiting dental caries developing.

Background to the invention It is known that chewing produces saliva which is a natural means of removing caries causing products from the teeth.

USA patents 5114704 and 6178922 disclose chewable products for dog dental care.

USA patent 5133971 proposes using a chewable membrane of reconstituted cellulose.

USA patent 4554154 discloses the use of a chewable tape carrying an adhesive.

USA patent 4891209 discloses a latex rubber masticating block [chewing gum size] which is intended to inhibit caries.

USA patent 5939049 discloses a chewing stick of jute or other natural fibres. It is claimed to be an improvement in the natural chewing sticks used by people in many developing countries.

USA patent 6123982 discloses an expandable dental floss and USA patent 6039054 to a dental floss having a foamed layer around the core.

Patent specification WO 00/32135 discloses a chewable foam strip of PE or EVA.

The foam cells are closed and smaller than 1mm in diameter.

A large proportion of caries infections occur in deep cracks and fissures which naturally occur in healthy teeth. There are three areas that are subject to tooth decay, gum margins and between teeth as well as inside pits and fissures.

However brushing and flossing, mouth wash, toothpaste and chewing gum can only access and benefit the first 2 areas. They cannot access inside pits and fissures where 80% of cavities occur.

The prior attempts as disclosed in the patents mentioned above do not effectively remove caries forming products from these deep cracks and fissures nor do they prevent those materials from entering the cracks and fissures. The only effective 2 It is an object of this invention to provide a product which prevents cariogenic food products breaking down into caries producing acid inside these cracks and fissures as well as between teeth and at gum margins by removing them.

Brief description of the invention To this end the present invention provides a 3 to 5mm thick dental care strip with outer IND open cup shaped cells cut from sheet closed cellular foam formed by extrusion of a thermoplastic like ethylvinyl acetate (EVA) with a nucleating agent like a fluoride or calcium salt and a foaming agent like butane. The soft thin edge of the slit outer half 0 10 cell walls scour plaque and food from tooth surfaces at gum margins like a brush, between teeth like floss as the inner cells compress under finger pressure and under chewing pressure, force saliva and dental agents or barrier materials inside pits and fissures where caries most commonly commence.

This invention is predicated on the discovery that tooth surfaces, deep cracks and fissures of teeth are not easily cleaned or penetrated by saliva which is being worked around by chewing gum or closed foam cells of WWOOO/321 5. The velocity of the saliva is higher when the foam cells are fractured, but it takes some time chewing before a sufficient number of cells are broken. This process is improved, preferably by slitting foam sheet that has about 1 mm diameter closed cells and soft thin compressible cell walls into 4 or 5mm thick strips giving a scouring and chewing area of outer cup shaped cells that easily fill with saliva and a strong central compressible cushioning matrix of closed cells that help propel the saliva inside pits and fissures and between opposing teeth with minimum lateral displacement as with a sponge or other chewy fibre. With this invention even 5 or 6mm thick foam strips can be compressed under finger pressure to pass effectively between the teeth.

In assessing the efficacy of various materials to provide sufficient force to the saliva to force it quickly into the deep cracks and fissures, a glass model of a fissured tooth has been studied using food dye to indicate penetration. This methodology has reduced the time needed to ascertaining if a procedure will benefit teeth from years (based on clinical trials) to a matter of hours.

The masticating strips of this invention are sized to give a chewing volume of I to 4 cm 3 preferably about 2 cm 3 The strips may be 50x20x2 mm in dimension with 1 mm foam cells but preferably are 1 5x2x1 00mm.

NO

0 Any food grade plastic foam may be used including thermoplastics such as ethylvynyl acetate (EVA), polyethylene polyvinyl acetate (PVA) or polyisobutylene (PIB) to Simprove cell size and provide thinner compressible cell walls and provide a chewy feel.

The foam strips of this invention may also be combined with barrier materials that are able to penetrate the deep cracks and fissures with the aid of the masticating strips of \NO this invention. These barrier materials are inert and prevent carbohydrate foods from S entering the cracks and fissures and prevent the formation of the acids which cause caries. Suitable barrier materials include cocoa, cheese and fine calcium salt particles 0 10 such as calcium carbonate combined with a carrier like gelatin. It is preferred to use a foam strip that provides a short acting bolus about 1cm 3 to deliver the barrier materials but not remove them.

A strip of foam of this invention in figure 1 is 2mm X 15mm X 100mm which creates a long acting chewy bolus volume of about 3cm 3 that remains chewy for a long time to clean the teeth or to remove barrier materials.

Detailed description of the invention To assist with understanding this invention, reference will now be made to the drawings. Fig 8 to Fig15 do not clearty show the imm diameter open or closed cells: Fig. 1. illustrates open outer cell foam strip of this invention with inner closed cells.

Fig. 2. illustrate a glass model of a fissure in a tooth, which simulates chewing.

Fig. 3,4, 5, 6 and 7. illustrate a fissure at one end of the glass model in Fig 2. subjected to chewing various foodstuffs and treatments; Figure 8 and 8b illustrate a snack food or confection, packaged with a dental foam strip to clean gum margins, between teeth and chew after eating the food product.

Fig. 9 illustrates another product configuration.

Figs 10 and 11. illustrate other packages utilizing the foam of this invention.

Fig 12 illustrates a conventional wrapped confection incorporating the foam of this invention.

Figure 13 illustrates of cross section through a foam strip showing open outer cells that are subject to chewing pressure with strong matrix inner cushioning cells and side skin that prevents lateral discharge of contents of open cells.

ilU~LAJ-/\J& Uo .r (i l Figs 14 and 15 illustrate 5mm thick foam slit horizontally and the two outer skin layers sandwiched in the middle to provide extra strength and support to the closed cell matrix held together by chewing gum, optionally with a dental adjuvant.

The glass model illustrated in figure 2 consists of two strips of glass about 5mm thick and 20mm wide and about 60mm long, stuck together with white silicone in an H fashion or clipped together with a thin Teflon gasket This leaves a very thin pocket or IND envelope open at each end as in fig. 2, replicating chewing actions observed inside pits and fissures. One end is forced into food or other material and saliva or water usually with a dye to clearly show if the food or other material saliva or water mix is 0 10 forced inside the fissure by the mix texture or consistency. Suitable fibre added to the mix greatly improves penetration inside pits and fissures and identifies if a stable short or long acting bolus is suitable to fill the pocket as illustrated in figure 3. Not every fibre or long acting bolus will force saliva etc inside the fissure. Chewing gum is a long acting bolus, which does not absorb and expel the fluids or mixtures and cannot remove material or dye from the model. Fig.4 illustrates the results of brushing or chewing gum in penetrating and removing food particles in cracks and fissures, and it can be seen that these have little effect. In contrast the foams of this invention provide complete penetration in a short time as illustrated in figure 5. when cheese is applied to the glass model as illustrated in Figure 6 cheese penetrates and seals the fissure. When normal food is applied to the glass model the results as illustrated in figure 7 demonstrate that it is difficult to remove.

The masticating dental foam of this invention may be made as follows: Polyethylene pellets are melted in an extruder with a fine nucleating powder such as flower of fluoride. 2% polyisobutylene and a foaming agent such as butane, propane, natural gas or carbon dioxide are pumped into the melt under controlled pressure to foam the mass as it exits the extruder die. This forms 1 mm diameter closed fine soft walted cells. The pressure should be close to the cell bursting pressure to facilitate creating a soft chewy foam. The foamed sheet may be surface treated with a wire roller or slitting blades to open the foam cells with slits.

Preferably the foam exits the die as a tubular sheet about 10 or 20 mm thick most preferably 15mm thick and is then slit vertically into strips 2 or 3mm thick. Sliting on an angle through the thickness is a possible alternative as it not only provides cup cells on the cut surface but improves ease of passing between teeth. Preferably the strips are rectangular 1 5mm by 50 or 1 00mm and 2mm thick. Another variation provided by this invention is V shaped strip in which the foam is not fully slit so that two strips are joined at one edge and the V shaped strip may be used to envelop the teeth.

A short acting bolus can be created with 5 mm cube foam blocks formed into jubes with a suitable barrier material. The addition of small amounts of polyisobutylene to the foam improves the foam by forming bigger cells and the foam is more chewy and IND is slightly tacky- Gelatin and PIB are used to prevent dehydration of the barrier material on the foam strips. The PE foam strips of this invention act as a bulking carrier that can run through a gelatin dip at much higher speeds than as individual 0 10 units and the coated strands pass up and down a drying, cooling setting tower before being cut and packed.

When slit, the cells provide a cup like surface that can hold saliva or an additive that is easy to force into pits and fissures immediately which is not possible with the smooth surface of a closed cell foam or even with punctured cells which close over under pressure. The exposed slit cell edges of this invention are also more efficient at plaque and food removal, cutting into and holding the plaque or food rather than sliding over it. Even square 5mm thick foam can be compressed so as to pass between the teeth while applying a slight orthodontic pressure that as well as clean teeth could aid jaw growth and help prevent crowded teeth.

Suitable dental agents such as one mg of fluoride may be incorporated inside the cells of each unit of dental foam to give 5ppm Fluoride ion in the saliva for about minutes after eating and perhaps before bed. It is desirable not to eat anything for about two hours after chewing the long acting fibre bolus to ensure complete remineralisatian so the ideal time for mineralisation with fluoride is before going to bed. This dosage is about 5 kilos of powdered NaF per ton of PE added at the hopper of the extruder as a nucleating agent giving about 30 billion cells in 15,000,000 units of dental foam each with a safe, effective level of 0. 15mg of topical fluoride. It is unlikely that the recommended dose of I1mg of fluoride per day would be exceeded.

Additives may also be applied to the foam by dipping or spraying before the foam is cut into strips as long as the open cells hold the additive.

The foam strip of this invention can be presented for use in a variety of ways. Figures 8A and B show two foam strips sealing a barrier food with two side tags. The side tags which are dental strips of this invention may be torn off and used after eating to remove food and neutralise acid. The dental strips of this invention which enclose WO 2004/039282 PCT/AU2003/001411 6 after eating to remove food and neutralise acid. The dental strips of this invention which enclose the barrier food is chewed prior to the meals to seal the cracks and fissures with a barrier material such as cheese. A similar product is illustrated in figures 9A and 9B in which the a barrier food is enclosed within a foam tube according to this invention with two dependent tags that can be torn off and used after eating to remove food.

The foam material of this invention can itself be used as a packaging material for foods or confections that can be used for cleaning teeth after the package is opened. Figurel0 depicts two strips of foam used to pack and seal a confection or snack.

Fig. 11i. Shows two strips of foam used to pack and seal a large confection or multiple units of the chewy device. As many as 50 units can be packed in this way to fit an average business envelope and day packs can be cut from this small bulk pack to serve as both barrier snacks before eating and cleaning device or gum after eating. The end sections of the pack can be used as reusable envelopes to carry a day supply of barrier snacks and cleaning devices even with a preferred toothpaste added.

Alternatively the dental strip of this invention can be combined with the wrapper of a confection as shown in figure 12 where a sweet 22 is enclosed in a conventional wrapping 20 and the foam 21 of this invention is also included. After eating the sweet the foam can be chewed so that the saliva generated by chewing the foam flushes the cracks and fissures of the teeth.

From the above it can be seen that this invention provides an effective dental hygiene material that is convenient to use at any time particularly prior to and after eating. Those skilled in the art will realize that the invention can be applied to a variety of applications and the size and volume of the masticating strips can vbe varied as desired. The dental adjuvants that are incorporated into the cells or applied to the surface of the strips may be chosen from among the wide range of materials currently available. Similarly other methods of manufacturing the slit cell foam strips may be employed.

Claims (19)

1. A dental care scouring, flossing, masticating strip of thermoplastic polymeric cellular foam in which the surface cells are open cup shaped cells.

2. A dental care strip of a cellular foam in claim I where the inner cels, are IND closed forming a central cushioning matrix and provides strength to help the strip to floss between teeth without tearing. 0 10

3. A dental care strip as claimed in claim 1 or claim 2, in which the foam cells are at least 1 mm in diameter.

4. A dental care strip as claimed in claim I in which the cell walls are soft, thin and chewy.

A dental care strip as claimed in claim 1 where the lateral cells are closed forming a lateral skin that helps prevent lateral dispersion of the saliva mix while chewing helping direct the pumping action inside pits and fissures.

6. A dental care strip as claimed in claim I or claim 2 where there is an inner double flat skin supporting and strengthening the inner closed cell strong central cushioning matrix.

7. A dental care strip as claimed in claim 6 where the inner double flat skin is formed from the outer skin of the closed cell foam sheet strips that are joined together after the strip is slit horizontally to give outer open cup shaped cell foam with~ the inners closed cell and central double skin matrix.

8. A dental care strip as claimed in claim 7 where the inner double ft skin is formed from one strip of outer open cup shaped cells on one side foam and with the skin of the other surface of closed cells, is folded back on each other and are joined together. 0

9. A dental care strip as claimed in claim 8 where the inner double fiat skin is joined together by suitable agents like chewing gum and prevents the chewing gum sticking everywhere and helps the foam fibre gum or agent mix absorb and expel saliva and scour tooth surfaces white controtling deivecy of flavour and dental agents. IND

10. A dental care strip as claimed in claim 9 where the foam sandwich has both outer and inner skins adding more chewy fibre that further helps chewing gum clean teeth and prevent the gum sticking everywhere. 0

11. A dental care strip as claimed in claim I or in claim 2 in which cellular foam is derived from thermoplastic material like polyethylene polyvinyl acetate (PVA), ethylvinylacetate (EVA) or potyisobutytene (PIB).

12. A dental care strip as claimed in claim 1 in which the nucleating agent that initiates the foaming of cells, is sodium fluoride or other suitable fluoride salt.

13. A dental care strip as in claim I where all cells compress under finger pressure to pass between teeth.

14. A dental care strip according claim I which can force a saliva mix with a dental adjuvant, inside pits and fissures in grooves on chewing surfaces.

A dental care strip as claimed in claim 14, in which the dental adjuvant is a sealant barrier material, preferably an insoluble noncariogenic material like calcium salt, even cheese, nut or cocoa as a fine powder, which is easily compacted under chewing pressure directed by this foam inside cracks and between teeth before eating to prevent food being trapped while eating and to help saliva displace trapped food after eating, neutralise acid and repair demineralised tooth.

16. A dental care strip as claimed in claim 15, in which the dental adjuvant is a mineralising agent like fluoride or antibacterial agent like chlorhexidine. L i It(f 1.4z/ 0

17. A dental care strip according claim 14 or claim 15 where the dental adjuvant is a solid insoluble barrier sealant material like barium sulphate to chew before xrays showing where food is trapped inside grooves on chewing surfaces while eating and where cavities are most Riely to develop when food is left trapped there after every meal or snack. IND

18. A dental care strip sized as claimed in claim 14 or claim 15 or claim 16 or claim 17, to give a short acting chewing bolus volume of 0.5 cm 3 tacn force dental agents or a barrier material deep into cracks and fissures in the C) 10 teeth, but is not able to help saliva remove the trapped sealant or dental agents. Chewing the foam with a sealant before eating, compacts the sealant barrier material to help prevent food being trapped while eating.

19. A dental care strip as claimed in claim 1, sized to form a long acting bolus volume of 1 to 4 cm 3 preferably about 3 cm 3 to help saliva with or without dental agents like fluoride or Recaldent, remove materials in the deep cracks and fissures of the teeth, neutralise acid and repair dem4nineralised tooth. A dental care strip as claimed in claim 1 or claim 11 that can package or be packaged with snack foods or dental agents as herein described with reference to the accompanying drawings. Maurice White 30 November 2006