RU2226060C2 - Shugar-free chewing gum for remineralization of dental enamel (variants) and method for remineralization of teeth - Google Patents

Abstract

FIELD: food industry, confectionary industry. SUBSTANCE: according to the first variant the suggested chewing gum contains water-insoluble part, water-soluble part, flavor and soluble calcium salt obtained due to premixing calcium carbonate and food acid taken at certain quantities. Method for remineralization of teeth deals with applying sugar-free chewing gum and its mastication. Moreover, chewing gum provides concentration of calcium ions in users' saliva being not less than 100 parts/mln. As a result, remineralization of dental enamel is achieved, risk for caries formation is decreased along with decreased expenses for manufacturing chewing gum. EFFECT: higher efficiency. 11 cl, 1 dwg, 11 ex

Description

FIELD OF THE INVENTION

The present invention relates to chewing gums. More specifically, the present invention relates to chewing gums, which may be useful for teeth.

With the exception of the common cold, dental caries (tooth decay) is the most common disorder in the human body. See The Merck Manual, sixteenth edition, p. 2480. Although many measures have been taken to reduce tooth decay and tooth decay, such as fluoridation and improved dental care, tooth decay remains a significant problem. This is especially true for adults; 80% of tooth decay occurs in 20% of the population. See Featherstone, An Updated Understanding of the Mechanism of Dental Decay and its Prevention, Nutrition Quarterly, Vol. 14, No. 1, 1990, p. 5-11.

To protect a normal tooth, a thin layer of tooth enamel forms a protective coating on the tooth. This coating mainly consists of calcium, phosphate and other ions in a hydroxyapatite-like structure. Enamel contains from 2 to 5 percent carbonate; this carbonate content makes the enamel susceptible to dissolution in acid. See Featherstone, ibid., P. 6.

It is believed that the interaction of three factors leads to dental caries: the sensitive surface of the tooth, the corresponding microflora, and a suitable base for microflora. Although several types of acidogenic microorganisms present in the mouth can cause carious damage, it is believed that Streptococcus mutans is the main pathogen. See The Merck Manual, above.

It is known that foods containing fermentable carbohydrates can contribute to the development of dental caries. Tooth decay begins when Streptococcus mutan, which is located mainly in the tartar on the surface of the tooth, assimilates fermentable carbohydrates that are consumed by the host. During the metabolism of bacteria capable of fermenting carbohydrates, lactic acid and other organic acids are released as a by-product. These acids reduce the pH value of the tartar / tooth environment.

When the value of the hydrogen indicator of the environment of the tartar / tooth falls below a critical level of 5.5-5.7, hydroxyapatite (calcium phosphate hydroxide, Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ ), the main component of tooth enamel, begins to dissolve . This critical value of the hydrogen index can vary depending on the concentration of the main ions. As a rule, dissolution begins below the porous surface of the tooth.

With repeated acid influences caused by further metabolism of bacteria capable of fermenting carbohydrates, surface damage expands. However, the natural remineralization mechanism in the human body at the moment can still reverse the destruction process. But if the lesions spread to a level at which the enamel surface is destroyed, a cavity forms and the process becomes irreversible.

The process of natural remineralization partially includes the flow of saliva on the tartar. Saliva can increase the pH of the environment. In addition, calcium and phosphate ions in the saliva precipitate and replace hydroxyapatite, which was dissolved by organic acids formed during the metabolism of carbohydrates capable of fermentation.

However, as a rule, this remineralization process takes place only at significant levels, when the magnitude of the hydrogen index is above the critical level (5.5-5.7). Therefore, if saliva does not increase the pH value sufficiently, significant remineralization will not occur. But the remineralization process can be enhanced by fluoride in the oral cavity, which accelerates the growth of new crystals and produces a fluoroapatite-like material that deposits on the surface of the crystals inside caries damage. See Featherstone, ibid., P. 7.

There is information that in some experiments, a number of salts counteracted demineralization. One problem is providing a viable vehicle for the delivery of such salts. In addition, in the case of some of these salts, a number of safety issues arise. And yet, sensory problems in relation to some of these salts prevent the patient from taking them on a regular basis to provide preventive benefits. Another problem is that these calcium salts can significantly increase the cost of the product.

Chewing gum uses compositions containing calcium. In particular, in a number of modern chewing gums, calcium carbonate is used as a base filler. In addition, calcium carbonate is used in chewing gum recipes to alter the chewing texture. Calcium carbonate is very water insoluble. Therefore, even if calcium carbonate is added to the base of chewing gum, it is not released in sufficient quantities in the mouth of the chewing gum in order to enhance the remineralization of tooth enamel.

Although it is known that acids are introduced into chewing gum to give it an acidic flavor, calcium carbonate is not commonly used in such situations. In this regard, talc is usually used as the base filler, since acids are neutralized by calcium carbonate.

US Pat. No. 5,378,171 discloses sugar chewing gum having beneficial dental health properties containing calcium glycerophosphate.

SUMMARY OF THE INVENTION

The present invention relates to a composition for remineralizing enamel, and a method for remineralizing enamel. In accordance with the present invention, there is provided a sugar-free chewing gum that contains a therapeutically effective amount of calcium and food acid. It has been found that food acids, when added to a calcium-containing base, convert insoluble calcium carbonate to its more soluble salt. This allows calcium to be released into the saliva in the mouth of the chewing. Thus, calcium is obtained, which can be used to enhance remineralizapia and / or reduce the demineralization of tooth enamel.

For this purpose, the present invention provides for the preparation of a sugar-free chewing gum comprising an insoluble portion, a water-soluble portion, a perfume, calcium carbonate and food acid.

In one embodiment, the food acid is selected from the group consisting of lactic acid, phosphoric acid, citric acid, malic acid, ascorbic acid, formic acid, fumaric acid, succinic acid, and tartaric acid.

In one embodiment, the calcium carbonate in the chewing gum comprises from about 0.1 to about 20% by weight.

In one embodiment of the present invention, chewing gum comprises at least one additional ingredient for oral health.

In one embodiment of the present invention, food acid in the chewing gum comprises from about 0.4 to about 5% by weight.

In one embodiment, the implementation of the present invention provides a sugar-free chewing gum comprising a water-insoluble part, a water-insoluble part, a sufficient amount of a composition containing an insoluble calcium salt to obtain a calcium ion concentration in the mouth of at least 100 ppm, and food acid.

In one embodiment, the food acid is selected from the group consisting of lactic acid, phosphoric acid, citric acid, malic acid, ascorbic acid, formic acid, fumaric acid, succinic acid, and tartaric acid.

In one embodiment of the present invention, the calcium carbonate-containing composition in the chewing gum comprises from about 0.1 to about 20 wt.%.

In one embodiment of the present invention, food acid in the chewing gum comprises from about 0.4 to about 5% by weight.

In yet another embodiment, a method of enhancing remineralization of teeth is provided. The method involves the presence of sugarless chewing gum, which includes a water-soluble part, a water-insoluble part, calcium carbonate and food acid; and chewing said sugar free chewing gum.

In one embodiment, two pieces of chewing gum are chewed at a time.

In one embodiment, chewing gum is chewed at least twice a day.

In one embodiment, chewing gum creates a concentration of calcium ions in the saliva of at least 100 ppm in the saliva.

In one embodiment, chewing gum creates a concentration of calcium ions in the saliva of at least 300 ppm in the saliva.

In one embodiment, chewing gum creates a concentration of calcium ions in the saliva of at least 500 ppm in the saliva.

In one embodiment, the concentration of calcium ions is maintained in saliva for at least 2 minutes.

An advantage of the present invention is the provision of a method for preventing or reducing the risk of dental caries.

Another advantage of the present invention is the provision of a method for remineralization of enamel.

And another advantage of the present invention is the treatment of dental caries.

In addition, an advantage of the present invention is to provide chewing gum, which can be used to improve dental health.

The advantages of the present invention also include the preparation of chewing gum, which does not have the sensory disadvantages of other calcium sources.

In addition, an advantage of the present invention is the provision of a simple and enjoyable way to improve dental health.

Another advantage of the present invention is that it provides chewing gum having beneficial properties for the teeth, and reducing the cost of its production.

An advantage of the present invention is also the preparation of an appropriate composition and the provision of a method for delivering a therapeutic agent over an extended period of time to the mouth.

Additional features and advantages of the present invention are described and will be apparent from the detailed description of the options for its implementation, which are currently preferred, and from the drawings.

Brief Description of the Illustrations

The drawing graphically presents salivary data indicating the amount of calcium released over time for examples 6-8, discussed below.

Detailed Description of Presently Preferred Embodiments of the Invention

The present invention provides methods and compositions for remineralizing tooth enamel. Thus, the present invention provides methods and compositions for preventing and / or treating dental caries. In accordance with the present invention, there is provided a chewing gum that contains a therapeutically effective amount of calcium and food acid; the chewing gum of the present invention can improve dental health when chewed.

In particular, it was found that the addition of food acids to a rubber base containing calcium carbonate converts insoluble calcium carbonate to its more soluble salt during chewing of the gum. Thus, gum enhances remineralization and / or reduces demineralization in the mouth of the chewing gum.

A variety of different food acids can be used. Such acids include lactic acid, phosphoric acid, citric acid, malic acid, ascorbic acid, formic acid, fumaric acid, succinic acid, tartaric acid, and mixtures thereof. For example, citric acid converts calcium carbonate to calcium citrate; lactic acid converts calcium carbonate to calcium lactate, and phosphoric acid converts calcium carbonate to calcium phosphate. It has been found that these acids maintain a pH value of about 5 to 7 when the acids are converted to their corresponding salts. Since food acid, such as citric acid, when added to sugar-free chewing gum containing calcium carbonate, turns insoluble calcium carbonate into its more soluble salt, it can enhance remineralization.

As a rule, food acids are much cheaper than the corresponding calcium salts. Calcium carbonate is very cheap and usually found in chewing gums. As a result, the chewing gums of the present invention are less expensive to manufacture than gums that are formulated with an equivalent calcium salt.

In a preferred embodiment, the chewing gum contains from about 0.1 to about 20 wt.% Calcium carbonate, even more preferably from about 1 to about 15 wt.% And most preferably from about 3 to about 12 wt.% Calcium carbonate. In the chewing gum, there should be enough calcium carbonate to create a concentration of calcium in saliva of at least 100 ppm, preferably at least 300 ppm, and most preferably at least 500 ppm for a period of at least 1 minute, preferably more than 2 minutes and most preferably for a period of 4 minutes after chewing the gum.

This is achieved by including at least 4 mg, preferably at least 5 mg, and most preferably 8 mg of food acid, for example citric acid, in each piece of chewing gum. In a preferred embodiment, a food-grade acid, for example citric acid, is mixed into a mass of chewing gum, but may also be pre-mixed with calcium carbonate before mixing into a mass of chewing gum.

As noted above, in addition to citric acid, other food acids can be used in the present invention, including phosphoric, lactic, malic, tartaric, formic, fumaric, succinic and ascorbic. It was found that these acids are more effective than others in the production of calcium ions in saliva during chewing. Although the inventors do not want to be bound by any particular theory, they believe that the reason for this is the acid dissociation constants and the solubility of the resulting calcium salt.

The composition of the chewing gum can be determined by any sugar-free chewing gum recipe. Typically, such recipes include a large amount of filler in the form of sugar alcohol, a substantial portion of the rubber base, small amounts of syrups, softeners, fragrances, dyes and high-intensity sweeteners. Low-calorie gum containing reduced amounts of sugar alcohols and increased amounts of base and / or low-calorie or non-caloric fillers are also allowed. The product may take the form of tablets, plates, relatively large pieces or coated pads. A preferred piece weight of the product is from about 1 to about 5 g.

As a rule, chewing gum consists of a water-insoluble rubber base, a water-soluble part and a perfume. The water-soluble portion is dispersed with the fragrance portion over a period of time during chewing. The part, which is a rubber base, is stored in the mouth throughout the entire chewing period.

The insoluble rubber base usually consists of elastomers, resins, fats and oils, softeners and inorganic fillers. The rubber base may or may not include wax. The insoluble rubber base may comprise from about 5 to about 95% by weight of the chewing gum, more often the rubber base is from 10 to about 50% by weight of the chewing gum, and in some preferred embodiments, from 20 to about 35% by weight of the chewing gum.

In one embodiment, the chewing gum base of the present invention contains from about 20 to about 60 wt.% Synthetic elastomer, from 0 to about 30 wt.% Natural elastomer, from about 5 to about 55 wt.% Elastomer plasticizer, from about 4 up to about 35 wt.% filler, from about 5 to about 35 wt.% softener, and optional small amounts (about 1% or less) of various ingredients, for example, colorants, antioxidants, and the like.

Used synthetic elastomers include, but are not limited to, polyisobutylene with a weight average molecular weight determined by gel permeation chromatography from about 10,000 to about 95,000, a copolymer of isobutylene and isoprene (butyl elastomer), styrene butadiene copolymers having proportions of styrene and butadiene from about 1 : 3 to about 3: 1, polyvinyl acetate having a weight average molecular weight determined by gel permeation chromatography from about 2000 to about 90,000, polyisoprene, polyethylene, VI copolymer yl acetate and vinyl laurate having a vinyl laurate content from about 5 to about 50 wt.% of the weight of the copolymer, and combinations thereof.

Preferred ranges of values are: for polyisobugylene, the weight average molecular weight determined by gel permeation chromatography is 50000-80000; for styrene-butadiene 1: 1-1: 3 bound styrene-butadiene; for polyvinyl acetate, the weight average molecular weight determined by gel permeation chromatography is 10,000 to 65,000, with higher molecular weight polyvinyl acetates usually being used as the basis for chewing gum from which bubbles can be inflated, and for vinyl acetate-vinyl laurate, the content of vinyl laurate is 10-45%.

Used natural elastomers may include natural rubber, such as smoked or liquid latex and guaula, as well as natural resins such as gelugong, caspi, perillo, tear, masranduba balata, chocolate massranduba, medlar, rosindinha, sapotilla juice, gutta hangant and their combinations. Preferred concentrations of the synthetic elastomer and the natural elastomer are different depending on whether the chewing gum, which uses the base, sticky or traditional gum, from which you can inflate the bubbles, or regular gum, as discussed below. Preferred natural elastomers are jelugong, sapotil juice, sorva, and massranduba balata.

Used elastomer plasticizers include, but are not limited to, natural esterified rosins, for example, partially hydrogenated rosin glycerol esters, rosin polymerized by glycerol esters, partially dimerized rosin glycerol esters, partially rosin glycerol esters, partially rosin glycerol esters, methyl pentaerythyrhenic esters and partially hydrogenated methyl rosin esters, pentaerythritol rosin esters, synthetic e substances such as terpene resins derived from alpha-pinene, beta-pinene and / or d-limonene; and any suitable combination of the above substances. Preferred elastomer plasticizers may also be different depending on the particular application and the type of elastomer used.

Useful fillers / texturizers may include magnesium and calcium carbonate, lime flour, silicates, for example magnesium and aluminum silicate, clay, alumina, talc, titanium oxide, calcium mono-, di- and triphosphate, cellulosic polymers, for example wood, and combinations thereof . In the present invention, calcium carbonate is a preferred filler, but other fillers may be used if calcium carbonate is added separately.

Softeners / emulsifiers used may include fat, hydrogenated fat, hydrogenated and partially hydrogenated vegetable oils, cocoa butter, glycerol monostearate, glycerol triacetate, lecithin, mono-, di- and triglycerides, acetylated monoglycerides, fatty acids, e.g. linoleic acid) and their combinations.

Dyes and bleaches used may include dyes and colorful varnishes such as FD&C, fruit and vegetable extracts, titanium dioxide, and combinations thereof.

The base may or may not include wax. An example of a wax-free rubber base is disclosed in US Pat. No. 5,286,500, the disclosure of which is incorporated herein by reference.

In addition to the water-insoluble part, which is a rubber base, a typical chewing gum composition includes a bulk water-soluble part and one or more perfumes. The water soluble portion may include bulk sweeteners, high intensity sweeteners, perfumes, emollients, emulsifiers, colorants, acidifiers, fillers, antioxidants and other components providing the desired properties.

Softeners are added to the chewing gum in order to optimize its chewing properties and the feeling of the gum in the mouth. Softeners, which are also known as plasticizers and plasticizing additives, typically comprise from about 0.5 to about 15 weight percent of the mass of chewing gum. Used softeners may include glycerin, lecithin, and combinations thereof. Aqueous solutions of emollients, for example, those containing sorbitol, hydrogenated starch hydrolysates, corn syrup, and combinations thereof, can also be used as emollients and binders in chewing gum.

Bulk sweeteners typically comprise from 5 to about 95 wt.% The mass of chewing gum, their more typical content is from 20 to 80 wt.%, And the more common is from 30 to 60 wt.% The mass of the gum.

Used sugarless sweeteners include, but are not limited to, sugar alcohols, for example sorbitol, mannitol, xylitol, hydrogenated starch hydrolysates, maltitol, and the like, alone or in combination.

High intensity artificial sweeteners may also be used, alone or in combination with the above. Preferred sweeteners include, but are not limited to, sucralose, aspartame, acesulfame salts, alitam, saccharin and its salts, cyclamic acid and its salts, glycyrrhizin, dihydrochalcones, thaumatin, monellin and the like, separately or in combination. In order to provide a longer sensation of sweetness and a perception of aroma, encapsulation or other containment of the release of at least some portion of the artificial sweetener may be desirable. Methods such as wet granulation, wax granulation, spray drying, spray cooling, fluidized bed coating, coacervation and fiber elongation can be used to achieve the desired release characteristics.

The extent to which an artificial sweetener is used can vary over a wide range and depends on factors such as the effectiveness of the sweetener, its release rate, the desired sweetness of the product, the content and type of flavoring agent used and cost considerations. Thus, the active content of an artificial sweetener can range from 0.02 to about 8%. If you take into account the media used for encapsulation, the degree of use of the encapsulated sweetener will be correspondingly higher.

Combinations of sugar and / or sugarless sweeteners may be used in chewing gum. In addition, the sweetener may also provide additional sweetness, for example, with aqueous solutions of sugar or aldit.

If low calorie chewing gum is desired, a low calorie bulking agent may be used. Examples of low calorie bulking agents include polydextrose, raftylose, raftilin, fructooligosaccharides (NutraFlora); Palatinose oligosaccharide; Guar Gum hydrolysates (Sun Fiber) or indigestible dextrin (Fibersol). However, other low calorie bulking agents may be used.

A variety of perfumes can be used. Fragrance can be used in amounts of from about 0.1 to about 15 wt.% By weight of the chewing gum, and preferably from 0.2 to 5%. Perfumes used may include essential oils, synthetic fragrances, or mixtures thereof, including, but not limited to, oils derived from plants and fruits, such as citrus oils, fruit essences, peppermint oil, spearmint oil, other peppermint oils, clove oil, Winterfish oil, anise and the like. Artificial fragrances and flavoring components may also be used. Natural and artificial fragrances can be combined in any sensoryly acceptable manner.

Additional ingredients useful for oral health may be added, including but not limited to additives to control the pH value (for example, urea and buffers), other inorganic components to combat tartar or caries (phosphates, fluorides) and additives that prevent tartar formation and anti-gingivitis supplements (including chlorhexidine, cetylpyridinium chloride, triclosan). Any additional ingredients should be safe and effective and should not undesirably react with calcium carbonate or a preferred food acid.

As examples of the present invention, but not limitation, the following information is provided:

It should be noted that in Example 4, a preliminary mixture of calcium carbonate and citric acid was used. Citric acid can be replaced with any food acid in any desired quantity. In Example 5, the recipe does not use additional calcium carbonate. The fact is that the acid can react with the calcium carbonate present in the base.

Tests were conducted to determine the effects of selected dietary acids with calcium carbonate on saliva, stimulated by chewing gum that does not contain sugar. Three people participated in the studies. They chewed the gum from Examples 6, 7, and 8. Each sample was evaluated over a 20-minute time period, and saliva was collected at certain intervals (without swallowing). Prior to the indicated period of 20 minutes, test subjects had to chew the measured sample of the rubber base (0.60 g +/- 0.05 g) for 2 minutes in order to establish the saliva calcium level at the initial level. The collected saliva samples were weighed, vortexed, diluted to a specific volume and analyzed in an atomic absorption analyzer in order to determine the calcium concentration, which was adjusted for the initial level of each test subject. Chewed gum was stored to perform mass balance calculations.

Three chewing gum recipes were prepared in accordance with Examples 6, 7 and 8 below. Kneading was done for a long time in order to ensure uniform distribution of food acid and calcium carbonate additives. The pieces of gum were cut into portions weighing 2.00-2.10 g and were aged for two weeks before testing. Samples were subjected to analytical tests in order to confirm the correct formulation and neutralize the acid.

In both examples of the inventive composition (7 and 1), more calcium was released during chewing than in the control example (6). In the drawing, these results are presented graphically.

The test results for inventive examples 7 and 8 correspond to the data expected based on the solubility of salts. Calcium carbonate becomes more soluble in acidic solution. The results are consistent with expectations based on the strength of the acid used and the solubility of the corresponding resulting salt. In addition, more calcium may be released during chewing to enhance dental benefits when the calcium salts are more soluble.

Based on these results, it was concluded that the addition of food acids to foods containing calcium carbonate does not increase the amount of calcium excreted in saliva. In addition, it should be noted that when using a stronger acid, a more soluble calcium salt can be obtained.

The trained specialists in sensory analysis held an expert group meeting on one control and two experimental chewing gums, each of which contained a different amount of citric acid. The tested chewing gum samples had the following formulation:

The expert group concluded that two experimental recipes using citric acid were acceptable in terms of gum from which bubbles could be inflated, but they did not match the taste profile of the control recipe. Each of the experimental samples showed acid at the beginning of the chewing process. The experimental gums began to become like a control sample after 30 seconds with the disappearance of signs of acidity. In addition, the bubbles inflated from two experimental samples were thin and weak. A sample containing 1.00% citric acid was found to be closest to the control.

It should be borne in mind that various changes and modifications of the currently preferred embodiments of the invention presented in the present description should be obvious to a person skilled in this field. Such changes and modifications can be made without deviating from the essence and without going beyond the scope of the claims of the present invention and without reducing its intended advantages. Therefore, it is assumed that such changes and modifications are covered by the attached claims.

Claims (11)

1. Sugar-free chewing gum for the remineralization of tooth enamel, including a water-insoluble part, which is a rubber base; water soluble part; fragrance and soluble calcium salt, which is obtained by pre-mixing calcium carbonate in an amount of about 0.1-20 wt.% by weight of chewing gum and food acid in an amount of about 0.4-5 wt.% by weight of chewing gum, from the group consisting of lactic acid, phosphoric acid, citric acid, malic acid, ascorbic acid, formic acid, fumaric acid, succinic acid and tartaric acid. 2. Sugar-free chewing gum according to claim 1, characterized in that it contains at least one additional ingredient that is healthy for the oral cavity, which is selected from the group: additive to control the magnitude of the hydrogen index, for example urea or buffer; inorganic component for combating tartar or caries, for example phosphate or fluoride; an additive that prevents the formation of tartar; anti-gingivitis supplement, e.g. chlorhexidine, cetylpyridinium chloride, triclosan. 3. Sugar-free chewing gum for remineralization of tooth enamel, including a water-insoluble part, which is a rubber base; water soluble part; soluble calcium salt which is obtained by premixing a sufficient amount of calcium carbonate to obtain a saliva in the mouth of the chewer of calcium ion concentration not lower than 100 million ^-1 and edible acid in an amount of about 0.4-5 wt.% of the chewing gum, and food the acid is selected from the group consisting of lactic acid, phosphoric acid, citric acid, malic acid, ascorbic acid, formic acid, fumaric acid, succinic acid and tartaric acid. 4. Sugar-free chewing gum according to claim 3, characterized in that the amount of calcium carbonate is approximately 0.1-20 wt.% By weight of the chewing gum. 5. Sugar-free chewing gum according to claim 3, characterized in that it contains at least one additional ingredient that is healthy for the oral cavity, which is selected from the group: an additive to control the magnitude of the pH value, for example urea or buffer; inorganic component for combating tartar or caries, for example phosphate or fluoride; an additive that prevents the formation of tartar; anti-gingivitis supplement, e.g. chlorhexidine, cetylpyridinium chloride, triclosan. 6. The sugarless chewing gum according to claim 3, characterized in that it contains a sufficient quantity of calcium carbonate to obtain a saliva in the mouth of the chewer of calcium ion concentration not lower than 300 million ^-1. 7. A method of remineralizing teeth, comprising providing a sugar-free chewing gum, including a water-soluble portion; a water-insoluble part, a soluble calcium salt, which is obtained by pre-mixing calcium carbonate in an amount of about 0.1-20 wt.% by weight of chewing gum and food acid in an amount of about 0.4-5 wt.% by weight of chewing gum, selected from the group consisting of lactic acid, phosphoric acid, citric acid, malic acid, ascorbic acid, formic acid, fumaric acid, succinic acid and tartaric acid; and said chewing a sugarless gum which provides in the saliva in the mouth of the chewer calcium ion concentration not lower than 100 million ^-1. 8. The method according to claim 7, characterized in that two pieces of chewing gum are chewed at a time. 9. The method according to claim 7, characterized in that the chewing gum is chewed at least twice a day. 10. The method according to claim 7, characterized in that the chewing gum provides in saliva in the mouth of the chewer calcium ion concentration not lower than 500 million ^-1. 11. The method according to claim 7, characterized in that said concentration of calcium ions in saliva is maintained for at least 2 minutes.

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