GB810345A - Dentifrice abrasive material - Google Patents

Abstract

Calcium pyrophosphate suitable for use as a dental abrasive consists of from 10 to 50 per cent beta-phase calcium pyrophosphate, the balance being substantially gamma-phase. The abrasive has a cleaning grade of at least 6.5, and a dentin abrasion value of not more than 700; both these items are defined in the Specification. The abrasive is preferably in the form of particles of which at least 80 per cent have diameters varying from 3m to 20m . Such calcium pyrophosphate may be prepared by treating calcium orthophosphate dihydrate to 500-700 DEG C., the heating being such that the temperature rises at an average rate of at least 50 DEG C./min. and in the range 100-300 DEG C. at a rate of at least 60 DEG C./min., and maintaining the calcium pyrophosphate so produced at a temperature of 500-700 DEG C. until at least 10 per cent but not more than 50 per cent of the pyrophosphate is in the beta phase, the balance being substantially in the gamma phase. The calcium orthophosphate dihydrate preferably has a median particle size of from 6 to 10m , with substantially no particles below 3m . The relative amounts of beta and gamma phase present may be determined by infra-red absorption spectrometry. The calcium pyrophosphate of the invention may be used in conventional dentifrice preparation (see Group VI). Specification 746,550, [Group VI], is referred to.ALSO:Dentrifrices contain an abrasive comprising from 10 to 50 per cent beta phase calcium pyrophosphate, the balance being substantially gamma phase calcium pyrophosphate, said abrasive having a cleaning grade of not less than 6.5 and a dentin abrasion value not exceeding 600. Preferably the calcium pyrophosphate is in the form of particles at least 80 per cent of which have diameters ranging from 3m to 20m . Toothpastes contain thickening materials, such as gum karaya, gum arabic, gum tragacanth, and other natural gums, seaweed derivatives such as Irish moss and alginates, or water-soluble salts of cellulose esters such as sodium carboxymethyl cellulose or sodium carboxymethyl hydroxymethyl cellulose. Sudsing agents may also be present, such as water-soluble alkyl and alkyl ether sulphates and sulphonates having alkyl groups of from 8 to 18 carbon atoms, water-soluble salts of sulphonated monoglycerides of fatty acids having from 10 to 18 carbon atoms, salts of fatty acid amides of Taurines such as sodium-N-methyl-N-palmitoyl Tauride, or salts of fatty acid esters of isethionic acid. Humectents, such as glycerine, sorbitols, and other polyhydric alcohols, may also be added. Texture may be improved by adding colloidal magnesium aluminium silicate. Flavouring colouring and sweetening materials may be added. The abrasive may be the calcium pyrophosphate alone or mixed with other abrasives. Other substances which may be added to the dentrifrices are sarcosinates, fluorine-containing compounds such as stannous fluoride, quaternary ammonia compounds, chlorophyll, sodium dehydroacetates, sodium lauryl sulphate, tyrothium, pencillin and hexachlorophene. Specification 746,550 is referred to.