IE51261B1 - Dental cream - Google Patents

Abstract

An opaque dental cream is disclosed comprising an opacifying agent e.g. TiO2 a binary fluorine system e.g. NaF/Na2PO3F and a synthetic silica polishing agent such as aluminosilicates. The creams may also contain dicalcium phosphate and/or pearlescent flakes.

Description

This invention relates to a dental cream for promoting oral hygiene.

In the past dental creams have been used which contain a single fluorineproviding agent such as sodium fluoride, stannous fluoride or sodium monofluorophosphate (it being understood that a minor part of commercial sodium monofluorophosphate includes sodium fluoride).

Recently, as in British Patent No. 1,435,624 of Beecham Group and U.S.

Patent No. 4,152,419 of Colgate-Palmolive dental creams for promoting oral hygiene have been described which contain two separately added fluorineproviding agents, that is sodium fluoride and sodium monofluorophosphate.

However, dental creams containing two such fluorine providing agents and a siliceous polishing material including a small amount of combined alumina have not been described.

It is an object of this invention to provide a dental cream containing sodium fluoride and sodium monofluorophosphate which promotes oral hygiene, for instance by reducing caries formation and by effecting dental remineralisation It is a further object to produce a silica abrasive dental cream of high fluorine stability.

According to the present invention a dental cream comprises 50 to 80% by weight of humectant, 2-7% by weight of water, and a binary fluorine-providing system which provides 750-1225 ppm fluorine from sodium monofluorophosphate and 50-1000 ppm fluorine from sodium fluoride, the weight ratio of the fluorine provided by the sodium monofluorophosphate to the fluorine provided by the sodium fluoride being in the range 10.8:1 to 2:1, and 15-20% by weight of a polishing agent consisting essentially of a synthetic silica containing up to 1% by weight of alumina interbonded therewith, opacified by the presence of 0.5-2% by weight of an opacifying agent, without which opacifying agent the dental cream would be visually clear.

Sodium monofluorophosphate is employed in amounts to provide 750-1225 ppm fluorine to the dental cream. This corresponds to 0.5-1% by weight of sodium monofluorophosphate in the dental cream. The preferred amount is 0.76% which provides about 1000 ppm fluorine to the dental cream.

Sodium monofluorophosphate, Na2PO3F, as commercially available may vary considerably in purity. It may be used in any suitable purity provided that any impurities do not substantially adversely affect the desired properties.

In general, the purity is desirably at least 80%. For best results, it should be at least 85%, and preferably at least 90% by weight of sodium monofluorophosphate with the balance being primarily impurities or by-products of manufacture such as sodium fluoride and water-soluble sodium phosphate salt. Expressed in another way, the sodium monofluorophosphate employed should have a total fluoride content of above 12% preferably above 12.7%, a content of not more than 1.5%, preferably not more than 1.2% of free sodium fluoride; and a sodium monofluorophosphate content of at least 12%, preferably at least 12.1% all calculated as fluorine.

Sodium fluoride is separately added to provide an additional fluorine amount of 50-1000 ppm (for example, 50-100 ppm). This corresponds to 0.01-0.02% of sodium fluoride.

The polishing material is a synthetic precipitated silica containing up to 1% by weight of alumina interbonded therewith. Such polishing materials may also be considered to be aluminosilicates, particularly sodium aluminosilicates. Typical examples are described in U.S. Patent No. 3,906,090 of Colgate-Palmolive and in U.S. Patents Nos. 4,015,996, 4,105,757 and 4,122,160 of J. M. Huber. Commercially available examples of these materials are ZEO 49 and ZEO 49 B of Huber and TIXOSIL 53 of Sifrance. The polishing agent is employed in amounts of 15-20% by weight.

If desired a minor amount, such as 0.5-1%, of dicalcium phosphate may be present as an additional polishing agent.

The dental cream of the invention is opaque. Since the polishing agent is characterised as having a refractive index close to that of humectants such as glycerine and sorbitol which are typically used in dental creams, 0.5-2% of an opacifying agent such as titanium dioxide or equivalent is employed.

The dental cream contains 50-80% by weight of humectant, such as 20-30% by weight of glycerine and 30-60% by weight of sorbitol (70% solution).

Other opacifying agents, such as zinc oxide, may be used in orally acceptable amounts which do not adversely react with other constituents of the dental cream.

Water is present, in small amounts, namely 2-7% by weight. If it is desired to colour the dental cream, colouring dyes may be dissolved in the water.

The dental cream also typically includes a gelling agent such as the natural and synthetic gum and gum-like material e.g. Irish moss, gum tragacanth, sodium carboxymethylcellulose, polyvinylpyrrolidone and starch.

Sodium carboxymethylcellulose is preferred. The gelling agent content is typically 0.1-5% by weight preferably 0.1-0.5%. The gelling agent effect can be supplemented with 7-8% of a filler such as a pyrogenic silica or a silica aerogel. ZEOSYL 200 of J. M. Huber is a desirable silica filler material. Zeosyl” is a trade mark.

Any suitable surface active or detersive material may be included in the dentifrice compositions. Such compatible materials are desirable to provide additional detersive, foaming and anti-bacterial properties depending upon the specific type of surface active material and are selected similarly. These detergents are water-soluble compounds usually, and may be anionic, nonionic or cationic in structure. It is usually preferred to use the water-soluble non-soap or synthetic organic detergents. Suitable detersive materials are known and include, for example, the water-soluble salts of typically C^-C^g fatty acid monoglyceride monosulphate detergent (e.g. sodium coconut fatty acid monoglyceride monosulphate) typically C12'C18 alkyl sulphate, (e.g. sodium lauryl sulphate), alkyl aryl sulphonate (e.g. sodium dodecyl benzene sulphonate), typically C^-C^g fatty acid esters of 1 ,Z-dihydroxy propane sulphonate.

Further surface active agents include the substantially saturated higher aliphatic acyl amides of lower aliphatic amino carboxylic acid compounds, such as those having 12 to 16 carbons in the acyl radical. The amino acid portion is derived generally from the aliphatic saturated monoaminocarboxylic acids having 2 to 6 carbons, usually the monocarboxylic acid compounds.

Suitable compounds are the fatty acid amides or glycine, sarcosine, alanine, 3-aminopropanoic acid and valine having 12 to 16 carbons in the acyl group.

It is preferred to use the N-lauroyl, myristoyl and palmitoyl sarcoside compounds, however for optimum effects.

The amide compounds may be employed in the form of the free acid or preferably as the water soluble salts thereof, such as the alkali metal, ammonium, amine and alkylolamine salts. Specific examples thereof are sodium and potassium N-lauroyl, myristoyl and palmitoyl sarcosides, ammonium and ethanolamine N-lauroyl sarsoside, N-lauroyl sarcosine, and sodium N-lauroyl glycide and alanine.

The surface active agent is typically employed in amount of 1-5% by weight, preferably 1-3% sodium lauryl sulphate is preferred.

Any suitable flavouring or sweetening materials may be employed in formulating 10 a flavour for the compositions of the present invention. Examples of suitable flavouring constituents include the flavouring oils, e.g. oils of spearmint, peppermint, Wintergreen, sassafras, clove, sage, eucalyptus, marjoram, cinnamon, lemon and orange, as well as methylsalicylate. Suitable sweetening agents include sucrose, lactose, maltose, sorbitol, sodium cyclamate and sodium saccharine. Sodium saccharine is preferred. Flavour is typically present in amount of 0.5-15% by weight, preferably 1% and sweetener in amount of 0.1-0.2%.

If desired visible particles of pearlescent flakes, such as titanium dioxide coated mica flakes, may be distributed in the dental cream, typically in amount of 0.1-0.3% by weight. Likewise, the dental cream may be striped.

The dental cream may be placed in conventional tubes such as lined or unlined aluminium tubes or wax lined lead tubes.

The dental creams should have a pH practicable for use. A pH range of 5 to 10 is particularly desirable. The reference to the pH is meant to be the pH determination directly on the toothpaste.

The following Examples are illustrative of the invention. All amounts are by weight unless otherwise specified.

EXAMPLE 1.

The following dental cream is prepared by conventional means: PARTS Glycerol 25.00 Sorbitol (70%) 42.31 Sodium Carboxymethyl Cellulose 0.18 Sodium Saccharine 0.17 Sodium Monofluorophosphate 0.82 Sodium Fluoride 0.02 Water 3.0 Titanium Dioxide 0.5 Silicon Dioxide-Low (about 1%) alumina 17.0 Zeosyl 200 7.0 Di calcium Phosphate Dihydrate 1.0 Sodium Lauryl Sulphate 2.0 Flavour 1.0 EXAMPLE 2.

A further dental cream is prepared, again by conventional means, with the formulation of Example 1 save that 0.25 parts of Titanium Dioxide coated mica flakes are added and the water content reduced by the same amount.

Table 1 which appears below, shows formulations of three dental creams which were prepared by conventional means, that identified as Example 3 being in accordance with the present invention. It will be seen that the formulation of Example 3 shows an increased fluorine level and increased fluorine retention over the test period compared with conventional opaque dental creams as exemplified by comparatives A and B.

The fluorine content was determined by the standard method set out by Cropper and Puttnam at p533 of Vol. 21 (1970) of The Journal of the Society of Cosmetic Chemists of Great Britain.

TABLE 1.

Comparative A Comparative B Example 3 Glycerol 22.222 20.202 25.0 Sorbitol (70% solution) - - 43.05 Sodium Carboxymethyl cellulose 0.9 1.1 0.2 Sodium Saccharine 0.2 0.2 0.17 Tetrasodium pyrophosphate 0.5 Benzoic acid - 0.2 - Titanium Dioxide - - 1.0 Sodium Monofluorophosphate 0.76 0.76 0.76 Sodium Fluoride 0.1 0.1 0.1 Water 25.018 23.138 3.96 Dicalcium phosphate dihydrate 48.0 - - Alumina (Alcoa 1) C333) - 52.0 - Zeo 49 - - 17.0 Syloid 1) 244 - - 6.0 Sodium Lauryl Sulphate 1.5 1.5 1.76 Flavour 0.8 0.8 1.0 Aging tests: Soluble Fluorine retention: Initial 0.110 0.121 0.132 (as % by weight) 1 month 0.103 0.111 - 3 months 0.093 0.104 0.140 6 months 0.081 0.096 0.138 1 year 0.069 0.090 - 2 years 0.061 0.080 1) Syloid and Alcoa are Registered Trade Marks.

Claims (6)

1. A dental cream comprising 50 to 80% by weight of humectant, 2-7% by weight of water, and a binary fluorine-providing system which provides 750-1225 ppm fluorine from sodium monofluorophosphate and 50-1000 ppm fluorine from 5 sodium fluoride, the weight ratio of the fluorine provided by the sodium monofluorophosphate to the fluorine provided by the sodium fluoride being in the range 10.8:1 to 2:1, and 15-20% by weight of a polishing agent consisting essentially of a synthetic silica containing up to 1% by weight of alumina interbonded therewith, opacified by the presence of 0.5-2% by weight of an 10 opacifying agent, without which opacifying agent the dental cream would be visually clear.

2. A dental cream as claimed in Claim 1 wherein the opacifying agent is titanium dioxide.

3. A dental cream as claimed in Claim 1 or Claim 2 wherein the sodium 15 fluoride provides 50-100 ppm fluorine.

4. A dental cream as claimed in any of the preceding claims containing 0.5-1% by weight of dicalcium phosphate.

5. A dental cream as claimed in any of the preceding claims containing 0.1-0.3% of pearlescent flakes. 20

6. An opaque dental cream substantially as described with reference to the Examples.