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WO2005065636A1 - Systeme abrasif pour les dents - Google Patents

Systeme abrasif pour les dents Download PDF

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Publication number
WO2005065636A1
WO2005065636A1 PCT/GB2005/000006 GB2005000006W WO2005065636A1 WO 2005065636 A1 WO2005065636 A1 WO 2005065636A1 GB 2005000006 W GB2005000006 W GB 2005000006W WO 2005065636 A1 WO2005065636 A1 WO 2005065636A1
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WO
WIPO (PCT)
Prior art keywords
abrasive system
abrasive
aluminosilicate
silica
range
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/GB2005/000006
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English (en)
Inventor
Peter William Stanier
Abraham Araya
Ian Patrick Mckeown
Jonathan Edwards Creeth
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Ineos Silicas Ltd
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Ineos Silicas Ltd
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Filing date
Publication date
Application filed by Ineos Silicas Ltd filed Critical Ineos Silicas Ltd
Publication of WO2005065636A1 publication Critical patent/WO2005065636A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • A61K8/24—Phosphorous; Compounds 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
    • A61K8/26—Aluminium; Compounds thereof
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K2800/00—Properties of cosmetic compositions or active ingredients thereof or formulation aids used therein and process related aspects
    • A61K2800/20—Chemical, physico-chemical or functional or structural properties of the composition as a whole
    • A61K2800/28—Rubbing or scrubbing compositions; Peeling or abrasive compositions; Containing exfoliants

Definitions

  • This invention relates to an abrasive system for use in high cleaning, controlled abrasivity dentifrice compositions and in particular to an abrasive system comprising a combination of crystalline aluminosilicate and water-soluble calcium sequestering agent.
  • Dentifrices commonly incorporate an abrasive material for mechanical cleaning and polishing of teeth by physical abrading deposits and they may also include a chemical cleaning agent.
  • the abrasive material is primarily intended to effect mechanical removal of deposits from the surface of teeth, e.g. removal of pellicle film adhered to the tooth surface.
  • Pellicle film is prone to discolouration and staining, e.g. by comestibles such as tea and coffee and by tars and particulates in exhaled cigarette smoke, resulting in an unsightly appearance of the teeth. While such mechanical removal is important for effective cleaning, it is vital that the abrasive used is not unduly harsh in order to minimise damage, e.g. scratching, to the teeth.
  • Synthetically produced amorphous silicas are often the favoured abrasive component in dentifrices and can be readily tailored during the production process to possess predetermined abrasive and other physical characteristics appropriate for use in dentifrices.
  • Precipitated silicas are particularly useful as abrasive components and are generally the material of choice in dentifrice compositions.
  • Frequently employed chemical cleaning agents comprise water-soluble salts capable of sequestering calcium ions present in deposits on the teeth so as to counteract and reduce plaque and calculus formation.
  • sequestering agents are selected in order to secure effective chemical cleaning without giving rise to undesired tooth demineralisation.
  • Crystalline aluminosilicates have been used as cleaning agents in dentifrice compositions. They possess a mechanical cleaning action (abrasivity) and are also known to bind calcium ions. Desirably, a dental cleaning agent combines relatively good cleaning with minimal abrasion of dentine. It has been found that most available zeolites are too abrasive to provide adequate cleaning without unacceptable abrasion when used in combination with silica cleaning agents.
  • an abrasive system for use in dentifrice compositions comprises a combination of a crystalline aluminosilicate having an average crystallite size below 1.0 ⁇ m (typically less than 0.1 ⁇ m) and a water-soluble, orally acceptable calcium sequestering agent.
  • an abrasive system for use in dentifrice compositions comprises a combination of a crystalline aluminosilicate having an RDA of less than 120 and a calcium binding capacity of at least 100 mg CaO per gram of anhydrous aluminosilicate and a water- soluble, orally acceptable calcium sequestering agent.
  • the abrasive system of the present invention may be incorporated in an orally acceptable carrier to produce a dentifrice composition.
  • orally acceptable carrier means a suitable vehicle which can be used to apply the resulting dentifrice composition to the oral cavity in a safe and effective manner.
  • the water-soluble calcium sequestering agent used in the abrasive system of the invention can comprise any one or more of the following:
  • Water-soluble alkali metal polyphosphates also known as condensed phosphate salts
  • M alkali metal, hydrogen ion or ammonium ion.
  • Pyrophosphates for example alkali and mixed alkali metal salts of pyrophosphate, and pyrophosphate salts in which hydrogen ion and/or ammonium ion may partially substitute for the alkali metal ions.
  • these are: Na 4 P 2 0 7 Tetrasodium pyrophosphate Na 2 H 2 P 2 ⁇ 7 Disodium dihydrogen pyrophosphate K 4 P 2 0 7 Tetrapotassium pyrophosphate K 2 H 2 P 2 O 7 Dipotassium dihydrogen pyrophosphate Na 2 K 2 P 2 ⁇ 7 Dipotassium disodium pyrophosphate
  • Tripolyphosphates for example alkali and mixed alkali metal salts of tripolyphosphate, and tripolyphosphate salts in which hydrogen ion and/or ammonium ion may partially substitute for the alkali metal ions. Examples are: Na 5 P 3 O 10 Pentasodium tripolyphosphate K 5 P 3 O 10 Pentapotassium tripolyphosphate
  • Higher polyphosphate salts such as sodium and potassium tetraphosphates, and hexametaphosphate salts, also known as 'glassy phosphates' or 'polypyrophosphates'.
  • Carboxylates for example: alkali metal citrate salts, which may be partially substituted with hydrogen ion or ammonium ion, alkali metal acetate, lactate, tartrate and malate salts, which may be partially substituted with hydrogen ion or ammonium ion.
  • Alkali metal salts of aminoacetates such as ethylenediaminetetraacetic acid (EDTA), which may be partially substituted with hydrogen ion or ammonium ion, and editronic acid.
  • EDTA ethylenediaminetetraacetic acid
  • Two or more of the above-mentioned calcium sequestering agents may be used in combination in the composition.
  • a preferred soluble calcium-sequestering agent is pentasodium tripolyphosphate, often referred to as sodium tripolyphosphate.
  • the calcium sequestering agent In use during toothbrushing, the calcium sequestering agent normally dissolves and so provides a cleaning effect in its dissolved state.
  • the composition of the invention may be so formulated that the calcium-sequestering agent is in a dissolved state during use in toothbrushing, or in an aqueous vehicle.
  • the water soluble calcium sequestering agent such as sodium tripolyphosphate
  • the water soluble calcium sequestering agent may be present in the range 0.1-20 per cent by weight, preferably 0.25-15 per cent by weight, more preferably 0.5-12 per cent by weight of the dentifrice composition.
  • a proportion of the calcium sequestering agent in the composition below the solubility limit thereof a gel or liquid compositions may be provided in which the calcium sequestering agent is in solution, so that the gel or liquid may include no undissolved solid particles, and may be a clear gel or liquid.
  • the components of the abrasive system of the invention are preferably in the dry state to ensure a free flowing powder with no microbial and preservation issues associated with filter cakes with high water content.
  • the physical water content as measured by loss at 105 °C associated with the system and/or its individual components is preferably less than 20% of the system or individual component.
  • Crystalline aluminosilicates useful in this invention can be represented by the formula: M 2/n O • AI 2 O 3 • xSiO 2 - yH 2 O wherein M represents a metal moiety, said metal having a valency of n, x indicates the molar ratio of silica to alumina and y indicates the ratio of molecules of water to atoms of alumina.
  • zeolites crystalline aluminosilicates
  • x Zeolite Molecular Sieves
  • Zeolites useful in this invention may be based on naturally-occurring or synthetic aluminosilicates but a preferred form of zeolite has the structure known as zeolite P.
  • Particularly preferred forms of zeolite are those disclosed in EP-A-0 384 070, EP-A-0 565 364, EP-A-0 697 010, EP-A-0 742 780, WO-A-96/14270, WO-A-96/34828 and WO-A- 97/06102, the entire contents of which are incorporated herein by this reference.
  • the zeolite P described in EP-A-0 384 070 has the empirical formula given above in which M represents an alkali metal and x has a value up to 2.66, preferably in the range 1.8 to 2.66, and has a structure which is particularly useful in the present invention. More preferably, x has a value in the range 1.8 to 2.4.
  • the zeolite P disclosed in the above patent literature is readily amenable to being produced with crystallite sizes well below 0.2 ⁇ m and agglomerate sizes below 2.5 ⁇ m, even when dried to a moisture content below 20% by weight. This contrasts with other zeolites which, on drying, tend to agglomerate to large weight mean particle sizes.
  • the average crystallite size of the crystalline aluminosilicate, measured using the test described hereinafter is preferably between 0.01 and 0.2 ⁇ m, usually between 0.02 and 0.1 ⁇ m and, more preferably between 0.02 and 0.08 ⁇ m or less.
  • the RDA of the crystalline aluminosilicate should be relatively low and is preferably less than 120, more preferably less than 100. Its RDA will usually be in excess of 30.
  • the RDA values which characterise the aluminosilicate, and other components, used in the abrasive system of this invention are measured using an aqueous slurry of the aluminosilicate, or other component, as defined in the test described hereinafter. If however the RDA were measured on the complete dentifrice composition i.e. including any optional components as defined hereinafter, the RDA values obtained may be significantly different.
  • the RDA of a typical dentifrice composition incorporating an abrasive system in accordance with the present invention would be in the range 25-200, preferably 30-180, and more preferably 50-150.
  • preferred aluminosilicates produce minimal scratching on dentifrice surfaces when used. Scratching can be assessed using the PAV test described hereinafter and preferred aluminosilicates have a PAV of 4 to 11 , preferably 4 to 9 and more preferably 4 to 7.
  • the aluminosilicate preferably has a calcium binding capacity, as hereinafter defined, of at least 100 mg CaO per gram of anhydrous aluminosilicate, preferably at least 130 mg CaO per gram of anhydrous aluminosilicate and most preferably at least 150 mg CaO per gram of anhydrous aluminosilicate.
  • the aluminosilicate preferably has an oil absorption of at least 40 cm 3 /100 g and preferably in the range 40 to 100 cm 3 /100 g.
  • the aluminosilicate preferably has a weight mean particle size as measured by Malvern Mastersizer , of at least 0.5 ⁇ m, more usually at least 1.0 ⁇ m, e.g. at least 1.8 ⁇ m.
  • the aluminosilicate preferably has a weight mean particle size as measured by Malvern Mastersizer ® , of at most 10.0 ⁇ m, more usually at most 5.0 ⁇ m e.g. at most 3.0 ⁇ m.
  • a most preferred range for the aluminosilicate is from 2.0 to 2.5 ⁇ m.
  • the preferred form of zeolite P is one in which M in the above formula consists of alkali metal ions.
  • suitable forms of zeolite P include those wherein a proportion of the alkali metal moieties M has been exchanged for other metal moieties, for instance as disclosed in published International Patent Application No. WO 01/94512.
  • Partially exchanged zeolites are particularly useful when it is desired to control the pH of the abrasive system.
  • Such pH adjustment step involves additional processing of the zeolite and associated cost. For this reason, as mentioned above, it is preferred to buffer the effect of the high pH zeolite by means of the silica content of the abrasive system and the inherent pH of the selected silica(s).
  • the pH of the aluminosilicate used in the abrasive system of the invention is usually in excess of 10. Where the aluminosilicate present in the system is one which has undergone such ion exchange, its pH will usually be no greater than 10.
  • the proportions of aluminosilicate and water-soluble calcium sequestering agent, e.g. alkali metal tripolyphosphate, present in the dental abrasive system of the invention can be varied in order to achieve a balance of properties suitable for the dentifrice composition in which it is used.
  • the proportion of aluminosilicate to water-soluble agent by weight is in the range 400 : 1 to 1 : 2.
  • the ratio is in the range 80 : 1 to 2 : 3, most preferably in the range 30 : 1 to 1 : 1 aluminosilicate to water-soluble agent by weight.
  • the components of the system may be mixed prior to combining the subsequent mixture with the other components of the dentifrice composition or may be separately added to the other components of the dentifrice composition.
  • the components (including any additional components of the system as referred to below) or mixture thereof will, at least prior to combining the same with other components of the dentifrice composition, usually be in the form of a substantially dry free flowing particulate material.
  • Additional components may also be present in the dental abrasive system of the invention.
  • One such component is a moderately abrasive amorphous silica, which has a low to medium RDA within the range 30 to 150. Typically its RDA is at least 40, more usually at least 50. Typically its RDA is no greater than 130, e.g. 110. It typically has an oil absorption of 60 to 140 cm 3 /100 g, preferably 80 to 120 cm 3 /100 g. It typically has a weight mean particle size in the range 5 to 15 ⁇ m, preferably 6 to 12 ⁇ m, the size being measured by a Malvern Mastersizer ® , as described hereinafter.
  • abrasive amorphous silica which is capable of acting as a booster to the cleaning ability of the system.
  • Preferred silicas suitable as boosters have an RDA of 100 to 300, preferably 100 to 220.
  • the silica preferably has an oil absorption of 40 to 150 cm 3 /100 g, and more preferably 40 to 100 cm 3 /100 g.
  • the weight mean particle size of the silica is preferably in the range 3 to 15 ⁇ m. More preferably, the silica has a weight mean particle size in the range 3 to 6 ⁇ m.
  • the amorphous silica or silicas employed is/are precipitated silica(s).
  • a further additional component can be a different crystalline aluminosilicate, e.g. an A, X or Y type zeolite, which acts as a cleaning booster (hereinafter referred to as "booster zeolite").
  • booster zeolite a different crystalline aluminosilicate
  • the amount of booster zeolite present will usually be less than that of the zeolite referred to hereinbefore (the "principal" zeolite).
  • This booster zeolite preferably has an RDA in the range 100 to 300 and more preferably in the range 100 to 250.
  • the PAV of the booster zeolite is preferably in the range 9 to 25 and more preferably in the range 9 to 20.
  • the values for both the RDA and the PAV of the booster zeolite will be greater than those for the principal zeolite.
  • the preferred oil absorption of the booster zeolite is in the range 30 to 100, more preferably in the range 30 to 50 cm 3 /100 g.
  • the weight mean particle size of the booster zeolite is preferably in the range 2.0 to 5.0 ⁇ m.
  • the booster zeolite preferably has an average crystallite size above 0.2 ⁇ m and most preferably above 1.0 ⁇ m.
  • the proportions of crystalline aluminosilicate and one or more additional particulate materials selected from moderately abrasive silica, booster silica or booster zeolite present in the dental abrasive system of the invention can be varied to provide optimum cleaning with controlled abrasion.
  • the proportion of crystalline aluminosilicate to such additional particulate materials, usually booster particles, by weight is in the range 40 : 1 to 1 : 1.
  • the ratio is in the range 9 : 1 to 3 : 2.
  • booster particles refers to booster silica, booster zeolite or a combination of booster silica and booster zeolite.
  • a dentifrice composition containing the abrasive system according to the present invention may also include a fluoride ion source as protection against demineralisation by bacteria (caries) and/or acidic components of the diet (erosion).
  • the fluoride ion source may be provided by any of the compounds conventionally used in toothpastes for these purposes, e.g. sodium fluoride, alkali metal monofluorophosphate, stannous fluoride and the like, with an alkali metal monofluorophosphate such as sodium monofluorophosphate being preferred.
  • the fluoride ion source serves in a known manner for caries protection.
  • the fluoride ion source will be used in an amount to provide a safe yet effective amount to provide an anti-caries and anti-erosion benefit such as an amount sufficient to provide from about 25 ppm to about 3500 ppm, preferably about 1100 ppm, as fluoride ion.
  • the formulation may contain 0.1 - 0.5 wt % of an alkali metal fluoride such as sodium fluoride.
  • the pH of the dentifrice composition incorporating an abrasive system of the present invention is from about 6 to 10.5, more preferably from about 7 to about 9.5.
  • the composition may contain sodium hydroxide, e.g. up to 1.0 wt.% or more, to provide a suitable pH.
  • the orally acceptable vehicle may be of a generally conventional composition e.g. comprising a thickening agent, a binding agent and a humectant.
  • Preferred binding agents include for example natural and synthetic gums such as xanthan gums, carageenans, alginates, cellulose ethers and esters.
  • Preferred humectants include glycerin, sorbitol, propylene glycol and polyethylene glycol.
  • a preferred humectant system consists of glycerin, sorbitol and polyethylene glycol.
  • the orally acceptable vehicle may optionally comprise one or more surfactants, sweetening agent, flavouring agent, anticaries agent (in addition to the fluoride ion source), anti-plaque agent, anti-bacterial agent such as triclosan or cetyl pyridinium chloride, tooth desensitizing agents such as potassium or strontium salts, such as potassium nitrate or strontium chloride, colouring agents and pigment.
  • useful surfactants include the water-soluble salts of alkyl sulphates having from 10 to 18 carbon atoms in the alkyl moiety, such as sodium lauryl sulphate, but other anionic surfactants as well as non-ionic, zwitterionic and cationic surfactants may also be used.
  • the dentifrice composition suitably contains from about 10 to about 80 wt % humectant such as sorbitol, glycerin, polyethylene glycol or xylitol; from about 0.25 to about 5 wt % detergent; from 0 to about 2 wt % sweetener; from 0 to about 2 wt % flavouring agents; together with water and an effective amount of binding and thickening agents, such as from about 0.1 to about 15 wt %, to provide the toothpaste of the invention with the desired stability and flow characteristics.
  • humectant such as sorbitol, glycerin, polyethylene glycol or xylitol
  • the abrasive systems of the invention are capable of providing dentifrice compositions with good cleaning and within the abrasion limits generally considered as acceptable.
  • the cleaning ability of a composition can be assessed by the test known as the NESR test (see Creeth JE, Wicks MA, Whitworth D, McConville PS. Improved in vitro model for developing toothpastes with optimised whitening performance. J. Dent. Res. 81 poster 652, 2002).
  • the tests used to characterise the components of the abrasive system of this invention are as follows.
  • RDA Radioactive Dentine Abrasion Test
  • the procedure follows the method for assessment of dentifrice abrasivity recommended by the American Dental Association (Journal of Dental Research 55(4) 563, 1976).
  • extracted human teeth are irradiated with a neutron flux and subjected to a standard brushing regime.
  • the radioactive phosphorus 32 removed from the dentin in the roots is used as the index of the abrasion of the dentifrice tested.
  • a reference slurry containing 10 g of calcium pyrophosphate in 50 cm 3 of 0.5% aqueous solution of sodium carboxymethyl cellulose is also measured and the RDA of this mixture is arbitrarily taken as 100.
  • a suspension of 10.0 g of the silica or aluminosilicate in 50 cm 3 of 0.5% aqueous solution of sodium carboxymethyl cellulose is prepared and the suspension is submitted to the same brushing regime.
  • a test slurry is prepared from 25 g dentifrice composition and 40 cm 3 of water and this slurry is submitted to the same brushing regime.
  • Plastics Abrasion Value This test is based upon a toothbrush head brushing a Perspex ® plate in contact with a suspension of the aluminosilicate in a sorbitol/glycerol mixture.
  • Perspex ® has a similar hardness to dentine. Therefore, a substance which produces scratches on Perspex ® is likely to produce a similar amount of scratching on dentine.
  • the slurry concentration is as follows:
  • Aluminosilicate 2.5g Glycerol 10.0 g Sorbitol Syrup* 23.0 g *Syrup contains 70% sorbitol/30% water
  • the test is carried out using a modified Wet Scrub Abrasion Tester produced by Sheen Instruments.
  • the modification is to change the holder so that a toothbrush can be used in place of a paintbrush.
  • a weight of 400 g is attached to the brush assembly, which weighs 145 g, to force the brush onto the PERSPEX sheet.
  • the toothbrush has a multi-tufted, flat trim nylon head with round ended filaments and medium texture, for example, the well-known Professional Mentadent P gum health design, or an equivalent toothbrush.
  • a galvanometer is calibrated using a 45° Plaspec gloss head detector and a standard (50% gloss) reflecting plate. The galvanometer reading is adjusted to a value of 50 under these conditions. The reading of the fresh PERSPEX sheet is then carried out using the same reflectance arrangement.
  • the fresh piece of PERSPEX sheet is then fitted into a holder. 2 cm 3 of the dispersed aluminosilicate, sufficient to lubricate fully the brushing stroke, is placed on the sheet and the brush head is lowered onto the sheet. The machine is switched on and the sheet is subjected to 300 strokes of the weighted brush head. The sheet is removed from the holder and all the suspension is washed off. It is then dried and its gloss value is determined again. The abrasion value is the difference between the unabraded gloss value and the gloss value after abrasion. This test procedure, when applied to known abrasives, gave the following typical values.
  • PAV Calcium carbonate (15 ⁇ m) 32 Silica xerogel (10 ⁇ m) prepared according to GB 1 262 292 25 Alumina trihydrate (Gibbsite) (15 ⁇ m) 16 Calcium pyrophosphate (10 ⁇ m) 14 Dicalcium phosphate dihydrate (15 ⁇ m) 7
  • the weight mean particle size of the silica or aluminosilicate is determined using a Malvern
  • Mastersizer ® model S with a 300 RF lens and MS17 sample presentation unit.
  • This instrument made by Malvern Instruments, Malvern, Worcestershire, uses the principle of Fraunhofer diffraction, utilising a low power He/Ne laser. Before measurement, the sample is dispersed ultrasonically in water for 5 minutes (in the case of silica) and 30 seconds (in the case of aluminosilicate) to form an aqueous suspension.
  • the Malvern Mastersizer ® measures the weight particle size distribution of the silica or aluminosilicate. The weight mean particle size (d so ) or 50 percentile and the percentage of material below any specified size are easily obtained from the data generated by the instrument.
  • the average crystallite size is determined from photographs made in a scanning electron microscope.
  • the crystalline aluminosilicate is dried to a water content of about 1 to 3 weight per cent and the agglomerates are broken up with a pestle and mortar. From the photographs, a sufficient number of crystals, e.g. 100, is counted and their size measured to determine a statistically significant average (arithmetical mean) size.
  • the aluminosilicate is first equilibrated to constant weight over saturated sodium chloride solution and the water content is measured. An amount is dispersed in 1 cm 3 water in an amount corresponding to 1 g dm "3 (dry weight) and the resulting dispersion is injected into a stirred solution of total volume 54.923 cm 3 , consisting of 0.01 M NaCI solution (50 cm 3 ) and 0.05M CaCI 2 (3.923 cm 3 ). This corresponds to a concentration of 200 mg of CaO per dm 3 , i.e. just greater than the theoretical maximum amount (197 mg) that can be taken up by an aluminosilicate of Si : Al ratio 1.00.
  • the dispersion is vigorously stirred at a temperature of 25° C for 15 minutes, after which time the Ca 2+ ion concentration is determined using a calcium electrode.
  • the Ca 2+ ion concentration measured is subtracted from the initial concentration to give the effective calcium binding capacity of the aluminosilicate sample.
  • the natural extrinsic stain removal (NESR) test is an in vitro brushing method that uses bovine enamel as the stained substrate.
  • Bovine teeth are extracted from jaws obtained from approved sources, depulped, disinfected in a solution of thymol and accepted or rejected for mounting based upon a visual assessment of the quantity of stain present on the surface of the tooth.
  • the stained bovine enamel specimens are then mounted into Ecotrin 30cc bottle caps (3.5cm diameter x 1.5cm depth) using acrylic powder and liquid.
  • a weartesting machine is used consisting of 28 stations into which mounted teeth and test solutions/slurries are placed.
  • Each station (or tray) is associated with a dedicated toothbrush (in particular, an "Oral B" 40 flat trim toothbrush or equivalent thereof) supported above the tray on a hinged metal arm.
  • a dedicated toothbrush in particular, an "Oral B" 40 flat trim toothbrush or equivalent thereof
  • Mounted bovine specimens are sited within each tray such that, when the metal arm is placed in the "down "position and the weartester activated, a continuous brushing motion over the surface of each tooth occurs at a fixed rate in a direction parallel to the surface of the bovine enamel specimen.
  • the force applied per stroke is targeted at approximately 100g, and a stroke rate of 100 strokes per minute.
  • Each mounted specimen is marked with 5 notches in permanent ink, positioned in an equidistant manner around the circumference of the Ecotrin cap.
  • the bovine enamel specimens were then ranked by L * value, and randomised across test cells to minimise experimental bias.
  • the test is run as a two-product head-to-head protocol, i.e. Test Product 1 (X) vs. Test Product 2 (Y).
  • the teeth are randomly divided into two sets. In the first treatment phase (T1 ), one set of teeth is brushed with a 1+1 w/w slurry of X in de-ionised water for 30 minutes and the second set is brushed with Y under the same conditions. The teeth are washed and dried overnight as above. The L* value is recorded and then the teeth undergo a second treatment phase (T2).
  • the relative stain removal efficacy of X versus Y is determined by comparing, for each treatment sequence, the percentage of stain removed during the first treatment phase as a proportion of the total amount of stain removed by both treatment phases. That is, whether: f ⁇ L*(T1 [X]) / ⁇ L*(T1 [X])+ ⁇ L*(T2[Y]) ] X 100
  • Values are constrained to be within the range 0-100%.
  • the quantities A, B and C are determined by the abrasive system under test (see Examples below).
  • the quantity of thickening silica ("D") is adjusted to ensure that the cohesion of the paste, as measured by the toothpaste cohesion test defined hereinafter, is in the range 150 to 430 g.
  • the cohesion of a toothpaste is a good measure of the "stand-up" properties of the ribbon when it has been extruded from a toothpaste tube onto a toothbrush. Higher cohesion values indicate firmer toothpaste ribbons, whereas low cohesion numbers are obtained from low viscosity, poorly structured toothpastes, which quickly sag into the bristles of the brush. It is generally required that a dentifrice has a cohesion within the range of 150 - 430g to provide a good quality, extrudable ribbon, which does not sag and is not too firm.
  • the basic principle of the test is to measure the weight in grams required to pull two parallel plates apart , which have a specific layer of toothpaste sandwiched between them.
  • the purpose built equipment consists of: 1 ) A spring balance in which the spring can be extended from 0 - 430g in 100mm of length.
  • the spring has a calibration scale of zero to 430g in 10g intervals and can be adjusted to zero at the start of the test.
  • a motor driven ratchet which is attached to the bottom plate and can be used to apply a constant, uniform, smooth vertical pull on the bottom plate of 5cm per minute.
  • a lower polished chrome circular plate of 76mm diameter which is attached underneath to a motor driven ratchet.
  • Two short pegs are located on the top of the plate so that the top plate can be positioned on the bottom plate concentrically from the centres.
  • a metal framework which allows the top plate to be situated concentrically above the bottom plate and the bottom plate to be adjusted so that the plate is approximately horizontal (achieved through the use of levelling feet on the base of the equipment).
  • This measurement is carried out on a 5 weight per cent suspension of the silica or aluminosilicate in boiled demineralised water (C0 2 free).
  • Ignition loss is determined by the loss in weight of a silica when ignited in a furnace at 1000° C to constant weight. Moisture Loss at 105° C
  • Moisture loss is determined by the loss in weight of a silica when heated in an oven at 105° C to constant weight.
  • Dentifrice Formulation 1 was used as a base formulation in which particle components A, B, C and D were varied according to the following examples and reference example:
  • Dentifrice formulation 1 was produced using 30% by weight Doucil A24 Zeolite, as the crystalline aluminosilicate (A), 10% by weight STPP - sodium tripolyphosphate - (C), and 5% by weight thickening silica (D) having a pH of 6.4.
  • the properties of Doucil A24 Zeolite are given in Table 1.
  • the toothpaste had an RDA of 104 and the cleaning data is given in Table 3.
  • Dentifrice formulation 1 was produced using 14% by weight Doucil A24 Zeolite as the crystalline aluminosilicate (A), 10% by weight sodium tripolyphosphate (C), 5% by weight thickening silica (D) having a pH of 6.4 and 4.2% by weight Sorbosil AC43 (as booster silica particles, B).
  • the properties of the cleansing particles used are given in Tables 1 and 2.
  • the toothpaste had an RDA of 114 and the cleaning data is given in Table 3.
  • Doucil A24 Zeolite is a crystalline aluminosilicate available from INEOS Silicas Limited, Warrington, UK.
  • Sorbosil AC43 is a toothpaste cleaning booster silica available from INEOS Silicas Limited, Warrington, UK.
  • Dentrifice Formulation 1 was produced using a standard silica abrasive (Control 1).
  • a and B were 0%, C was 10% and D was 6.5%.
  • the RDA of this formulation is about 85.
  • the cleaning data are presented in Table 3. The data show a substantial increase in cleaning efficacy for a modest increase in abrasivity.
  • Dentrifice Formulation 1 was also produced as a second control using a different standard silica abrasive (Control 2).
  • a and B were 0%, C was 10% and D was 5.5%.
  • the RDA of this formulation is about 130.
  • the data are presented in Table 3. The cleaning data show that the aluminosilicate formulation gives equivalent cleaning efficacy but lower abrasivity.

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Abstract

L'invention concerne un système abrasif destiné à être utilisé dans des compositions pour dentifrice à abrasion contrôlée et nettoyant puissant comprenant une combinaison d'aluminosilicate cristallin présentant une taille de cristal moyenne inférieure à 10 µm et un agent chélateur de calcium soluble dans l'eau, et pouvant être administré oralement. L'aluminosilicate cristallin peut présenter une abrasion dentaire radioactive (RDA) inférieure à 120 et une capacité de fixation du calcium d'au moins 100 mg CaO par gramme d'aluminosilicate anhydrique. L'agent chélateur de calcium soluble dans l'eau et pouvant être administré oralement peut être le tripolyphosphate de sodium.
PCT/GB2005/000006 2004-01-09 2005-01-05 Systeme abrasif pour les dents Ceased WO2005065636A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0400414.9 2004-01-09
GB0400414A GB0400414D0 (en) 2004-01-09 2004-01-09 Dental abrasive system

Publications (1)

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WO2005065636A1 true WO2005065636A1 (fr) 2005-07-21

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4193987A (en) * 1977-12-22 1980-03-18 Blendax-Werke R. Schneider Gmbh & Co. Non-corrosive toothpaste
GB2082454A (en) * 1980-08-21 1982-03-10 Grace W R & Co Dentifrice composition containing zeolite
WO1986002830A1 (fr) * 1984-11-16 1986-05-22 Union Carbide Corporation Dentifrice effervescent
WO2001094512A1 (fr) * 2000-06-02 2001-12-13 Ineos Silicas Limited Compositions a base de zeolite et leur utilisation

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4193987A (en) * 1977-12-22 1980-03-18 Blendax-Werke R. Schneider Gmbh & Co. Non-corrosive toothpaste
GB2082454A (en) * 1980-08-21 1982-03-10 Grace W R & Co Dentifrice composition containing zeolite
WO1986002830A1 (fr) * 1984-11-16 1986-05-22 Union Carbide Corporation Dentifrice effervescent
WO2001094512A1 (fr) * 2000-06-02 2001-12-13 Ineos Silicas Limited Compositions a base de zeolite et leur utilisation

Also Published As

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