Opacified dental cream containing a binary fluorine-providing system

An opacified dental cream which effects dental remineralization and reduces caries formation. The opacified dental cream contains a binary fluorine providing system which provides fluorine from sodium monofluorophosphate and from sodium fluoride, a synthetic precipitated silica containing up to about 1% by weight of alumina polishing agent and an opacifying agent.

FIELD OF THE INVENTION 
This invention relates to a dental cream for promoting oral hygiene. 
DESCRIPTION OF THE PRIOR ART 
In the past dental creams have been used which contain a single 
fluorine-providing 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 Pat. No. 1,435,627 of Beecham Group and U.S. Pat. 
No. 4,152,719 of Colgate-Palmolive dental creams for promoting oral 
hygiene have been described which contain two separately added 
fluorine-providing 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. 
SUMMARY OF THE INVENTION 
According to the present invention an opaque dental cream comprises 0.5 to 
2% by weight of an opacifying agent, a binary fluorine-providing system 
which provides about 750-1225 ppm fluorine from sodium monofluorophosphate 
and about 50-1000 ppm fluorine from sodium fluoride and about 15-20% by 
weight of a polishing agent consisting essentially of a synthetic 
precipitated silica containing up to about 1% by weight of alumina 
interbonded therewith. 
Sodium monofluorophosphate is employed in amount to provide about 750-1225 
ppm fluorine to the dental cream. This corresponds to about 0.5-1% by 
weight of sodium monofluorophosphate in the dental cream. The preferred 
amount is about 0.76% which provides about 1000 ppm fluorine to the dental 
cream. 
Sodium monofluorophosphate, Na.sub.2 PO.sub.3 F, 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 about 50-1000 ppm (for example, 50-100 ppm). This corresponds to 
about 0.01-0.2% of sodium fluoride. 
The polishing material is a synthetic precipitated silica containing up to 
about 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. Pat. No. 
3,906,090 of Colgate-Palmolive and in U.S. Pat. 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 about 15-20% by weight. 
If desired a minor amount, such as about 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 
characterized as having a refractive index close to that of humectants 
such as glycerine and sorbitol which are typically used in dental creams, 
about 0.5-2% of an opacifying agent such as titanium dioxide or equivalent 
is employed. The dental cream typically contains about 50-80% by weight of 
humectant, such as about 20-30% by weight of glycerine and about 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 may be present too, in small amounts, such as about 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 carboxymethyl cellulose is preferred. The gelling agent content is 
typically about 0.1-5% by weight preferably about 0.1-0.5%. The gelling 
agent effect can be supplemented with about 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 higher fatty acid monoglyceride 
monosulphate detergent (e.g. sodium coconut fatty acid monoglyceride 
monosulphate), higher alkyl sulphate (e.g. sodium lauryl sulphate), alkyl 
aryl sulphonate (e.g. sodium dodecyl benzene sulphonate), higher fatty 
acid esters of 1,2-dihydroxy propane sulphonate and the like. 
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 lower aliphatic saturated 
monoaminocarboxylic acids having about 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 about 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 sarcoside, N-lauroyl sarcosine, and 
sodium N-lauroyl glycide and alanine. 
The surface active agent is typically employed in amount of about 1-5% by 
weight, preferably about 1-3% sodium lauryl sulphate is preferred. 
Any suitable flavouring or sweetening materials may be employed in 
formulating 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 about 
0.5-15% by weight, preferably about 1% and sweetener in amount of about 
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 about 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 about 
5 to 10 is particularly desirable. The reference to the pH is meant to be 
the pH determination directly on the toothpaste.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
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: 
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TS 
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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 
Synthetic precipitated silica containing 
about 1% combined alumina 
17.0 
Zeosyl 200 7.0 
Dicalcium Phosphate 
Dihydrate 1.0 
Sodium Lauryl Sulphate 2.0 
Flavor 1.0 
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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 
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Com- Com- 
para- para- 
tive tive Exam- 
A B ple 3 
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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 C333) -- 52.0 -- 
(synthetic precipitated silica containing 
about 1% combined alumina) 
Zeo 49 -- -- 17.0 
Syloid 244 -- -- 6.0 
Sodium Lauryl Sulphate 
1.5 1.5 1.76 
Flavor 0.8 0.8 1.0 
Aging tests: 
Soluble fluoritine 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 -- 
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