Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61Q—SPECIFIC USE OF COSMETICS OR SIMILAR TOILETRY PREPARATIONS
  • A61Q11/00—Preparations for care of the teeth, of the oral cavity or of dentures; Dentifrices, e.g. toothpastes; Mouth rinses
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
  • A61K8/19—Cosmetics or similar toiletry preparations characterised by the composition containing inorganic ingredients
  • A61K8/20—Halogens; Compounds thereof
  • A61K8/21—Fluorides; Derivatives thereof
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
  • A61K8/19—Cosmetics or similar toiletry preparations characterised by the composition containing inorganic ingredients
  • A61K8/24—Phosphorous; Compounds thereof

Definitions

• This invention relates to dentifrice compositions, particularly toothpastes, which, in spite of the presence of a calcium-containing polishing agent for cleaning the teeth, are capable of furnishing fluorides to the' teeth for their known prophylactic function of protectingthe teeth against caries.
• a further object of my invention is the provision of calcium-containing dental polishing agents which are more compatible with fluorides and can be incorporated in dentifrice preparations containing fluoride. with a minimumloss of fluoride to the inactive water-insoluble form.
• the duration of treatment required to accomplish a given improvement influoride'compati bility of a given orthophosphate is less at the higher temperatures.
• the temperature should not be, so high as to cause incipient fusion of the phosphate, however, since additional steps would then'be required to reduce. themas's to a finely divided powder of dentifrice grade.
• the complete formula for the precipitated orthophosphate has been described as Ca (PO -l-I O
• the in accuracy of describing this water as true water of hydration is generally as well recognized as is the inaccuracy of the Ca (PO structure itself, because (1) the amount of this water is not a constant percentage of the weight even for a given Ca/P ratio and (2) this water is more dificult to remove than the customary water of hydration requiring temperatures of from 200 to-800 C. for removal.
• this water content is present in one or more of three forms, namely 1) as OH groups in the hydroxpreceding paragraph not only 7 ylapatite lattice, (2) in Ca(OH) or H PO adsorbed or occluded within the particles of precipitated tricalcium orthophosphate or (3) as molecular water adsorbed or occluded within the particles of precipitated tricalcium orthophosphate.
• Evidences and suggestions of the presence of these forms have been presented by severalworkers' including Hodge, Lefevre and Bale (see above), Hendricks and Hill .in Proceedings of the National Acaderny of Sciences 36, 731-737 (1950), and Posner and Stephenson in Journal of Dental Research 31, 371-382 (1952).
• precipitated tricalcium orthophosphates contain a considerable amount of water which is present neither as free moisture nor as true Water of hydration and most of which requires temperature well above 200 C. for removal. This is the water in precipitated tricalcium orthophosphates" which, whether itis adsorbed, occluded or combined, is referred to as water more tightly held than true water of hydration. Loss of this-water and/or changes in crystal size are the only significant changes noted on heat treating precipitated tricalcium orthophosphates below 700-- 800 C.
• the material tends to be converted by suflicient heat treatment to .fl-tricalcium phosphate and ultimately to a-tricalcium phosphate, entirely different' crystalline forms'which can bedistinguished by means of Xrays from the initial precipitate having the typical hydroxylapatite X-ray pattern.
• the initial empirical composition of the precipitated orthophosphate is fairly close to the hydroxylapatite formula the material tends to be converted by suflicient heat treatment to oxyapatite [Ca (PO 0] which is also disting'uishable by X-rays. Bale et al.
• fluoride-compatible abrasives for use in the present invention are most readily obtained by heat treating conventional calcium orthophosphate abrasives since these latter materials are readily available in the proper form for use in dentifrices.
• the maximum increase in fluoride compatibility is obtained by heat treating said calcium orthophosphates to the point of complete conversion to the end products discussed above, namely 3- or a-tricalcium orthophosphate or calcium oxyapatite, calcium pyrophosphates and calcium metaphosphates but for the sake of avoiding additional steps of regrinding and classifying to proper particle size it is preferred that fusion be avoided during heat treatment.
• the preferred temperatures are above 200 C,.but should not exceed 900 C.; with dicalcium orthophosphates alone, temperatures from 300 to 1100 C. are most usable; while with precipitated tricalcium orthophosphates beneficial heat treatment may be effected at any temperature'from 300 to 1500 C. although almost never is there an additional advantage to be gained in heating the material above 13001400 C. and generally temperatures above 1000 to 1100 C. would not be pre ferred. It should be remembered that when mixtures of the above species or when mixed salts containing other metal cations in addition to calcium aretreated, the fusion temperatures will tend to be lowered and restriction of temperatures to the upper limits given above can not be strictly relied upon to avoid incipient fusion.
• calcium metaphosphate refers to a monomeric compound represented by the formula Ca(PO and the term calcium polyphosphates refers to polymeric calcium phosphates, whether in the form of rings or straight chains, and includes calcium pyrophosphate (calcium dipolyphosphate).
• straight calcium salts are pre-' ferred, mixed salts containing both calcium and other metal cations in addition are also included within the scope of this invention.
• Example I most entirely converted to calcium pyrophosphate The improved compatibility of this material.
• Dentifrice grade dicalcium orthophosphate dihydrate usually contains a fraction of a percent of a stabilizer, .such as Na4PzO7 or M g (PO added for the purpose of preventing loss of water of hydration during longtime storage at climatic temperatures.
• a stabilizer such as Na4PzO7 or M g (PO added for the purpose of preventing loss of water of hydration during longtime storage at climatic temperatures.
• M g PO added for the purpose of preventing loss of water of hydration during longtime storage at climatic temperatures.
• dicalcium orthophosphate dihydrate containing either, both, or neither of these stabilizers, or even anhydrous dicalcium orthophosphate could be substituted as starting materials in the above experiments without nullifying the beneficial effects of the heat treatment.
• Anhydrous dicalcium orthophosphate' is not appreciably more compatible with-fluoride ion than is the corresponding dihydrate, and heat treatment which is suflicient only to remove water of hydration is of
• Example II A quantity of powdered monocalcium orthophosphate monohydrate spread in a uniform layer on a clean, un-' reactive heat-resistant surface is placed in an oven heated to a uniform and constant temperature of 650 C. After Zhours at this temperature the treated material is found to be almost completely converted to calcium metaphosphate and much more compatible with fluorides than formerly as shown by the following experiment.
• Example III Precipitated dentifrice grade tricalcium orthophosphate meeting specifications set out by the National Formulary is subjected to a temperature of 815 C. for -1 hour.
• the treated material is found to be greatly improved over the original tricalcium phosphate with respect to fluoride-compatibility as shown by the figures obtained on available fluoride remaining in a solution originally 1000 p. p. m. in fluorine (as SnF after contacting samples of same with measured quantities of the respective abrasives. These. figures were 50% available from the heat treated material but only 12% from ,the control. Such moderate heat treatment does not produce a preferred abrasive of this invention.
• Example IV Some of the calcium pyrophosphate prepared. in Ex ample I by heating dicalcium orthophosphate dihydrate for one hour at a temperature of 815 C. was used in making a fluoride-containing toothpaste of the following composition:
• the Irish moss extract was wet out in part of the glycerine and the calcium pyrophosphate was wet out in part of the water, in which the synthetic detergent had been dissolved. These slurries were then mixed'together with heating until a uniform temperature of C. was reached. The thickened paste mixture was then cooled to a temperature of 35 C. and the flavoring, the remaining glycerine and the remaining water containing the stannous fluoride were all added and mixed in tho:- oughly to give a homogeneous paste of suitable consistency.
• This paste was then compared for its ability to release fluoride in solution with a similar product of the same composition with the one exception that untreated dicalcium orthophosphate was .used as the abrasive instead of the heat-treated material which had been converted largely to pyrophosphate by the heat-treatment
• the comparison test was made by analyses of the supernatant liquid phases obtained from slurries of the pastes in water.
• the preferred concentration is about 0.1% fluoride-producing fluorine (or about 0.4% stannous fluoride) which is equivalent to about 1000 p. p. In. F. In any case it is believed that there would seldom be any significant additional. advantage in using more than 1% fluoride-producing fluorine ($10,000 p. p. m.) in the composition of the present invention regardless of toxicity questions, which have not yet been fully settled for products of this .type.
• These fluorine concentrations may be furnished in the form of any non-toxic fluorine-containing compounds, which normally dissociate in aqueous solution to yield fluoride ions including fluorides such .as
• NaF, SnF- ZnF SnF can, NH4F, KF, LiF, CrF
• the more complex fluorine-containing salts of the same metals or ammonia such as the fluosilicates e. g. Na SiF and also fluotitanates etc., as well as mixed halides such as chlorofluorides of the same metals or ammonia, -e. g. SnClF.
• dentifrice compositions prepared according to the teachings of this invention are the following.
• Example V A commercial sample of calcium pyrophosphate. pre
• the process of preparing this paste was as follows: The gum tragacanth was wet out in part of the glycerine; the synthetic detergent and the sodium fluoride remaining ingredients of these pastes without affecting the were dissolved in the water and the remaining glycerine added to this solution. The pyrophosphate was then wet out in the aqueous mixture and this slurry was then mixed with the gum tragacanth slurry and the combined mass was heated to C. and cooled to 32 C. while being mixed continuously. Finally the flavor was added and mixed in thoroughly to give a homogeneous finished paste product.
• Example VI The heat-treated monocalcium orthophosphate prepared in Example 11 by heating conventional monocalcium orthophosphate for 2 hours at 650 C. was used in making a fluoride-containing powder dentifrice according to the following formulation:
• Heat-treated monocalcium orthophosphate from The available fluoride in a slurry of this dentifrice was determined by the same procedure described in connection with the analyses of Example IV and was found to be 100% of that added as SnF In contrast, a similar tooth powder prepared with unheat-treated monocalcium orthophosphate yielded only 49% of its total fluoride in available form when analyzed in the same way.
• a dentifrice combining a fluorine-containing compound and an abrasive, in which said fluorine-containing compound is one which normally dissociates to yield fluo ride ions in aqueous solution, and which is present in said dentifrice in an amount which contains at least 0.01%, by weight, of ionizable fluoride but not more than 0.4%,
• abrasive is present as at least 20%, by weight, of said'dentifrice and comprises essentially at least one material selected from the group consisting of calcium polyphosphates, calcium metaphosphate, calcium oxyapatite, and pand a-tricalcium orthophosphates.
• a toothpaste combining a fluorine-containing compound and an abrasive, in which said fluorine-containing compound is one which normally dissociates to yield fluoride ions in aqueous solution and which is present in said dentifrice in an amount which contains at least 0.01%, by weight, of ionizable fluoride but not more than 0.4%, by weight, of total fluorine, and in which said abrasive is present as from 20% to 60%, by weight, of said dentifrice and comprises essentially at least one material selected from the group consisting of calcium polyphosphates, calcium metaphosphate, calcium oxyapatite, and B- and u tricalcium orthophosphates.
• a toothpaste comprising by weight from about 10% to 40% of water, from about 10% to 40% glycerine, stannous fluoride in an amount equivalent to 0.01% to 0.4% of fluorine, and from about 20% to 60% of calcium pyrophosphate.
• a toothpaste comprising by weight from about 10% to 40% of water, from about 10% to 40% of glycerine, sodium fluoride in an amount equivalent to 0.01% to 0.4% of fluorine and from about 20% to 60% of calcium pyrophosphate.
• McClendon A reprint from J. Dental Res., vol. 26,

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Cited By (29)

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Citations (10)

• 0
  • BE BE539808D patent/BE539808A/xx unknown
• 1953
  • 1953-07-08 US US366867A patent/US2876166A/en not_active Expired - Lifetime
• 1954
  • 1954-03-16 GB GB7649/54A patent/GB746550A/en not_active Expired

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