U.S. patent application number 10/338160 was filed with the patent office on 2004-02-05 for dentinal desensitizing dentifrice providing enhanced remineralization and anticaries benefits.
This patent application is currently assigned to Colgate-Palmolive Company. Invention is credited to Fisher, Steven W., Heu, Rodman T., Joziak, Marilou T., Stranick, Michael A., Sullivan, Richard J..
Application Number | 20040022747 10/338160 |
Document ID | / |
Family ID | 31187820 |
Filed Date | 2004-02-05 |
United States Patent
Application |
20040022747 |
Kind Code |
A1 |
Fisher, Steven W. ; et
al. |
February 5, 2004 |
Dentinal desensitizing dentifrice providing enhanced
remineralization and anticaries benefits
Abstract
A dental composition which eliminates or substantially reduces
the discomfort and pain associated with dentinal hypersensitivity
and exhibits enhanced anticaries and remineralization benefits
which composition contains a fluoride ion and a potassium ion
releasable salt and has a pH in the range of about 8 to about 9.9,
the pH being buffered with phosphate salt.
Inventors: |
Fisher, Steven W.;
(Middlesex, NJ) ; Joziak, Marilou T.; (South
River, NJ) ; Sullivan, Richard J.; (Somerset, NJ)
; Stranick, Michael A.; (Bridgewater, NJ) ; Heu,
Rodman T.; (Chatham, NJ) |
Correspondence
Address: |
Colgate-Palmolive Company
909 River Road
P.O. Box 1343
Piscataway
NJ
08855-1343
US
|
Assignee: |
Colgate-Palmolive Company
|
Family ID: |
31187820 |
Appl. No.: |
10/338160 |
Filed: |
January 7, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10338160 |
Jan 7, 2003 |
|
|
|
10212660 |
Aug 5, 2002 |
|
|
|
Current U.S.
Class: |
424/52 ;
424/57 |
Current CPC
Class: |
A61K 8/21 20130101; A61K
2800/88 20130101; A61K 2800/52 20130101; A61K 8/19 20130101; A61K
8/24 20130101; A61Q 11/00 20130101 |
Class at
Publication: |
424/52 ;
424/57 |
International
Class: |
A61K 007/18; A61K
007/16; A61K 009/14 |
Claims
What is claimed is:
1. A dental composition which eliminates or substantially reduces
the discomfort and pain associated with dentinal hypersensitivity
and exhibits enhanced anticaries and remineralization benefits
which composition comprises a fluoride ion and a potassium ion
releasable salt, the composition having a pH in the range of about
7.5 to about 9, the pH being buffered with an alkali metal
phosphate salt, whereby application to teeth requiring relief from
dentine hypersensitivity results in heightened desensitization as
well as heightened tooth fluoridation and remineralization.
2. The composition of claim 1 wherein the potassium ion releasable
salt is potassium nitrate.
3. The composition of claim 1 wherein the fluoride releasable salt
present in the composition delivers a fluoride ion concentration of
about 1100 to about 8800 ppm.
4. The composition of claim 1 wherein the fluoride ion releasable
salt is sodium fluoride.
5. The composition of claim 1 wherein the pH is buffered with a
sodium phosphate salt.
6. The composition of claim 1 wherein the pH is buffered with a
combination of sodium mono and di-basic phosphate salts.
7. The composition of claim 1 wherein the alkali metal phosphate
salt is present in the composition at a concentration of about 1.0
to about 10% by weight.
8. A method for eliminating or reducing the discomfort and pain
associated with dentinal hypersensitivity concomitant with
enhancing tooth remineralization and reducing the occurrence of
caries, which method comprises preparing a dentifrice having a pH
buffered with a phosphate salt in the range of about 7.5 to about
9.0 and containing a desensitizing potassium ion releasable salt
and a fluoride ion releasable salt, dispensing the composition for
application to teeth requiring relief from dentine hypersensitivity
and thereafter applying the composition to the teeth whereby
heightened tooth desensitization, enhanced tooth remineralization
and increased fluoride uptake is experienced by the user.
9. The method of claim 6 wherein the potassium ion releasable salt
is potassium nitrate.
10. The method of claim 8 wherein the fluoride salt present in the
composition delivers a fluoride ion concentration of about 1100 to
about 8800 ppm.
11. The method of claim 8 wherein the fluoride ion releasable salt
is sodium fluoride.
12. The method of claim 8 wherein the alkaline dentifrice component
is an aqueous dentifrice having a pH of about 9 to about 11.
13. A two component dental composition which eliminates or
substantially reduces the discomfort and pain associated with
dentinal hypersensitivity which composition comprises a first
dentifrice component having a neutral pH in the range of about 6.5
to 7.5, the pH being buffered with a phosphate salt, a second
dentifrice component having an alkaline pH in the range of about
8.0 to about 9.9, and at least one of the components containing a
fluoride ion or potassium ion releasable salt, the first and second
components being maintained separate from each other until
dispensed and combined for application to teeth requiring relief
from dentine hypersensitivity, whereby heightened desensitization
enhanced remineralization and increased fluoride uptake is
experienced by the user.
14. The composition of claim 13 wherein each component contains a
fluoride ion and a potassium ion releasable salt.
15. The composition of claim 13 wherein the potassium ion
releasable salt is potassium nitrate.
16. The composition of claim 13 wherein the fluoride salt present
in the dual component composition delivers a fluoride ion
concentration of about 2500 to about 8800 ppm.
17. The composition of claim 13 wherein the fluoride ion releasable
salt is sodium fluoride.
18. The composition of claim 13 wherein the alkaline dentifrice
component is an aqueous dentifrice having a pH of about 8.0 to
about 9.9.
19. The method of claim 13 wherein the pH of the neutral pH
dentifrice component is buffered with a sodium phosphate salt.
20. The composition of claim 13 wherein the pH of the alkaline
dentifrice component is adjusted with sodium hydroxide.
21. The method for eliminating or reducing the discomfort and pain
associated with dentinal hypersensitivity which comprises preparing
(1) a first dentifrice component having a neutral pH buffered with
a phosphate salt in the range of about 6.5 to about 7.5 and (2) a
second dentifrice component having an alkaline pH in the range of
about 8.0 to about 9.9, at least one of the components containing a
desensitizing potassium ion releasable salt and a fluoride ion
releasable salt, separately housing the first and second
components, dispensing the first and second components and
combining the dispensed components for application to teeth
requiring relief from dentine hypersensitivity and thereafter
applying the combined components to the teeth whereby heightened
desensitization is experienced by the user.
22. The method of claim 21 wherein each component contains a
fluoride ion and a potassium ion releasable salt.
23. The method of claim 21 wherein the potassium ion releasable
salt is potassium nitrate.
24. The method of claim 21 wherein the fluoride salt present in the
composition delivers a fluoride ion concentration of about 1100 to
about 8800 ppm.
25. The method of claim 21 wherein the fluoride ion releasable salt
is sodium fluoride.
26. The method of claim 21 wherein the alkaline dentifrice
component is an aqueous dentifrice having a pH of about 8.0 to
about 9.9.
27. The method of claim 21 wherein the pH of the alkaline
dentifrice component is adjusted with sodium hydroxide.
28. The method of claim 21 wherein the pH of the neutral pH
dentifrice is buffered with a sodium phosphate salt.
Description
[0001] This application is a continuation-in-part of Ser. No.
10/212,660 filed Aug. 5, 2002.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a desensitizing dentifrice
composition which eliminates or reduces the discomfort and pain
associated with dentinal hypersensitivity and more particularly to
a desensitizing dental composition containing a potassium salt
desensitizing agents which exhibits unexpected enhanced anticavity
and remineralization properties.
[0004] 2. The Prior Art
[0005] Dentinal hypersensitivity is defined as acute, localized
tooth pain in response to physical stimulation of the dentine
surface as by thermal (hot or cold) osmotic, tactile combination of
thermal, osmotic and tactile stimulation of the exposed dentin.
[0006] Exposure of the dentine, which is generally due to recession
of the gums, or loss of enamel, frequently leads to
hypersensitivity. The art has determined that dentine tubules open
to the surface have a high correlation with dentine
hypersensitivity, Abs, J. Clin. Periodontal. 14,280-4 (1987).
Dentinal tubules lead from the pulp to the cementum. When the
surface cementum of the tooth root is eroded, the dentinal tubules
become exposed to the external environment. The exposed dentinal
tubules provide a pathway for transmission of fluid flow to the
pulpal nerves, the transmission induced by changes in temperature,
pressure and ionic gradients.
[0007] It is known to the art that potassium salts are effective in
the treatment of dentinal hypersensitivity. For example, U.S. Pat.
No. 3,863,006 discloses that toothpastes containing potassium salts
such as potassium nitrate desensitize the teeth after tooth
brushing for several weeks. It is believed by those skilled in the
art that an elevation in the extracellular potassium concentration
in the vicinity of pulpal nerves underlying sensitive dentin is
responsible for the therapeutic desensitizing effect of topically
applied oral products which contain potassium nitrate. Due to
passive diffusion of potassium ion into and out of the open dentine
tubules, repeated application of the active ingredient is necessary
to build up the necessary concentration in the vicinity of the
pulpal nerves.
[0008] It is believed that the improved pain relief is obtained
from the use of potassium salts in combination with gradual
mineralization on the dentin surface which can either totally or
partially occlude dentin tubules. Total occlusion will dramatically
reduce fluid flow within the tubules which stimulates pain. Partial
occlusion of the dentin tubules is believed to increase delivery of
potassium ion inside the tooth because the inward diffusive flux is
less dependent upon tubule radius than outward fluid flow (due to
positive pulpal pressures) (See D H Pashley and W G Mathews, Archs.
Oral Biol. (1993) 38, 577-582). Therefore, this enhanced delivery
of potassium should enhance relief.
[0009] It has also long been known to include fluoride releasing
compounds in dentifrices as anticaries agents, and it has been
established that these compounds are effective to reduce the
incidence of dental caries. Fluoride compounds which are
conventionally used are sodium fluoride, sodium monofluorophosphate
and stannous fluoride. The fluoride compounds are effective mainly
due to the fluoride ions which improve the acid resistance of tooth
enamel and accelerate recalcification or remineralization of
decayed teeth in their early stage when the demineralization has
proceeded only slightly. By remineralization, pre-existing tooth
decay and caries can be reduced or eliminated thereby reducing
preexisting carious conditions in the tooth structure. The effect
of improving the acid resistance of the enamel is believed to be
due to the fact that the fluoride ions are incorporated into a
crystal lattice of hydroxyapatite which is the main constituent of
tooth enamel or, in other words, fluoride ions partially fluoridate
hydroxyapatite and simultaneously repair the lattice
irregularities.
[0010] The effectiveness of fluoride treatment is dependent upon
the amount of fluoride ion which is available for deposition on the
enamel being treated. It is, therefore, desirable to formulate
dentifrice compositions which provide maximum fluoride ion
availability in brushing solutions formed using the dentifrice.
[0011] While the prior art discloses the use of various oral
compositions for the treatment of dentinal hypersensitivity, dental
caries, and enamel demineralization there is still a need for
additional compositions and methods which provide improved
performance in such treatments.
SUMMARY OF THE INVENTION
[0012] In accordance with the present invention there is provided
an oral composition and method for the treatment of dentinal
hypersensitivity which exhibits improved anticavity and
remineralization properties, the composition containing a fluoride
ion releasing salt and a potassium releasable salt compound in an
orally acceptable vehicle in which the fluoride compound is present
at a concentration sufficient to release about 500 to 8800 parts
per million (ppm) fluoride, the composition being buffered to
maintain an alkaline pH of about 7.5 to about 9 whereby upon
repeated application of the composition to the teeth increased
relief from dentinal hypersensitivity is experienced by the user
accompanied by improved resistance to cavities.
IN THE DRAWINGS
[0013] FIG. 1 is a SEM recorded at 2,000.times. magnification, of a
dentin disk surface treated with a dual component dentifrice
containing high concentrations of a fluoride salt which releases
5000 ppm fluoride ion (1.1% by weight) and potassium nitrate (5% by
weight), wherein the first component is buffered to a pH of 6.5 and
the second component adjusted to a pH of 9.5 with sodium hydroxide,
the pH of the combined components being 7.5.
[0014] FIG. 2 is a SEM recorded at 2,000.times. magnification, of a
dentin disk surface treated with the combined components of a
comparative dual component dentifrice of the prior art (U.S. Pat.
No. 6,180,089) containing 5% potassium nitrate and a fluoride
containing salt which releases 1100 ppm fluoride ion wherein one
component is maintained at alkaline pH and the second component
maintained at an acid pH, the pH of the combined components being
7.0.
[0015] FIG. 3 is a scanning electron photomicrograph (SEM) recorded
at 2,000.times. magnification of a dentin disk surface treated with
a phosphate buffer solution.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] The composition of the present invention may be a single
phase composition or a dual phase composition.
[0017] The dual phase composition is comprised of two components in
which a first dentifrice component is maintained at an alkaline pH
of about 8.5 to about 9.9 and preferably about 9.0 to about 9.9,
and a second dentifrice component is buffered to maintain the pH at
a substantially neutral pH level of 6.5 to 7.0. The two components
are preferably combined in approximately equal weight proportions,
so that about one-half of the concentration of any particular
ingredient within either component will be present when the
components are combined and applied to the teeth, as by brushing.
Both components are preferably formulated to have similar physical
characteristics, so that the two components may be simultaneously
delivered in the desired predetermined amounts by extrusion when
separately housed in a multicompartmented tube or pump device.
[0018] When the dentifrice of the present invention is to be
prepared as a single phase product, a buffering agent is
incorporated in the dentifrice component which is normally prepared
using as a vehicle, one which contains water, humectant, surfactant
and an abrasive. The pH of such single component dentifrice is in
the alkaline pH buffered in the range of about 7.5 to about 9.0 and
preferably about 8.5 to about 9. The buffering agent is preferably
an alkali metal phosphate salt and most preferably a mixture of
mono- and dibasic sodium phosphate salts. Each phosphate salt is
present in the dentifrice at a concentration of about 1.5 to about
5% by weight. The combined amount of buffering agents incorporated
in the dentifrice composition is at a concentration of about 5 to
about 10% by weight and preferably about 6 to about 10% by
weight.
[0019] In a dual component dentifrice of the present invention, the
one dentifrice component is prepared having an alkaline pH and a
composition otherwise similar to that of the other having a
buffered neutral pH. The pH of the alkaline component is adjusted
to a pH of about 8.5 to about 9.7 and preferably about 9.0 to about
9.5. The pH of the combined dentifrice components is in the range
of about 7.5 to about 8.6 and preferably about 7.5 to about 8.5
[0020] An alkaline agent such as an alkali metal compound including
sodium hydroxide, potassium hydroxide, sodium bicarbonate, sodium
carbonate, N-sodium silicate a sodium silicate in 34.6% water
available from PQ Corporation) is incorporated in the alkaline pH
dentifrice component of the dual component dentifrice in amounts in
the range of about 0.5 to about 15% by weight, preferably about 1.0
to about 8% by weight and most preferably at about 1.0 to about
5.0% by weight of the component. Mixtures of the above alkali metal
compounds may also be used. Sodium hydroxide is the preferred
alkaline agent.
[0021] The humectant used in the preparation of the vehicle for the
dentifrice composition of the present invention is generally a
mixture of humectants, such as glycerol, sorbitol and a
polyethylene glycol of molecular weight in the range of 200 to
1000, but other mixtures of humectants and single humectants may
also be employed. The humectant content is in the range about of
10% to about 50% by weight and preferably about 20 to about 40% by
weight of the dentifrice component. The water content is in the
range of about 20 to about 50% by weight and preferably about 30 to
about 40% by weight.
[0022] Thickeners used in the preparation of the dentifrice vehicle
include organic and inorganic thickeners. Inorganic thickeners
which may be included in the dentifrice components include
amorphous silicas such as Zeodent 165 available from Huber
Corporation, and Sylox 15 from W. R. Grace.
[0023] Organic thickeners of natural and synthetic gums and
colloids may also be used to prepare the dentifrice components of
the present invention. Examples of such thickeners are carrageenan
(Irish moss), xanthan gum, sodium carboxymethyl cellulose, starch,
polyvinylpyrrolidone, hydroxyethylpropylcellulose, hydroxybutyl
methyl cellulose, hydroxypropyl methyl cellulose, and hydroxyethyl
cellulose.
[0024] The inorganic thickener may be incorporated in the
dentifrice composition of the present invention at a concentration
of about 0.5 to about 5% by weight and preferably about 1 to about
3% by weight. The organic thickener may be incorporated in the
compositions of the present invention at a concentration of about
0.1 to about 3% by weight and preferably about 0.4 to about 1.5% by
weight.
[0025] Surfactants may be incorporated in the dentifrice
compositions to provide foaming properties. The surfactant is
preferably anionic or nonionic in nature. Suitable examples of
anionic surfactants are higher alkyl sulfates such as potassium or
sodium lauryl sulfate which is preferred, higher fatty acid
monoglyceride monosulfates, such as the salt of the monosulfated
monoglyceride of hydrogenated coconut oil fatty acids, alkyl aryl
sulfonates such as sodium dodecyl benzene sulfonate, higher fatty
sulfoacetates, higher fatty acid esters of 1,2 dihydroxy propane
sulfonate.
[0026] The surfactant agent is generally present in the dentifrice
component composition of the present invention at a concentration
of about 0.5 to about 10.0% by weight and preferably about 1.0 to
about 5.0% by weight.
[0027] Abrasives may be incorporated in the dentifrice composition
of the present invention and preferred abrasives are siliceous
materials, such as silica. A preferred silica is a precipitated
amorphous hydrated silica, such as Sorbosil AC-35, marketed by
Crosfield Chemicals, or Zeodent 115 from Huber Company but other
abrasives may also be employed, including hydroxyapatite, sodium
metaphosphate, potassium metaphosphate, tricalcium phosphate,
calcium phosphate dihydrate, anhydrous dicalcium phosphate, calcium
pyrophosphate, magnesium orthophosphate, trimagnesium phosphate,
calcium carbonate, sodium bicarbonate, alumina trihydrate, aluminum
silicate, calcined alumina and bentonite.
[0028] The concentration of abrasive in the dentifrice composition
of the present invention will normally be in the range of 5 to
about 40% by weight and preferably about 10 to 25% by weight.
[0029] The source of desensitizing potassium ion is generally a
water soluble potassium salt including potassium nitrate, potassium
citrate, potassium chloride, potassium bicarbonate and potassium
oxalate with potassium nitrate being preferred. The potassium salt
is generally incorporated in one or more of the dentifrice
components at a concentration of about 1 to about 20% by weight and
preferably about 3 to about 10% by weight.
[0030] Fluoride ion releasing salts are incorporated in the
dentifrice composition of the present invention and are
characterized by their ability to release fluoride ions in water.
It is preferable to employ a water soluble fluoride salt providing
about 1000 to about 9000 ppm of fluoride ion, and preferably about
2500 to about 8800 ppm of fluoride ion. Suitable examples of
fluoride ion releasing salts include water soluble inorganic metal
salts, for example, sodium fluoride, potassium fluoride, sodium
monofluorophosphate, stannous fluoride and sodium fluorosilicate.
Sodium fluoride, sodium monoflurophosphate and stannous fluoride
are preferred fluoride ion releasing salts.
[0031] Pyrophosphate salts having anticalculus efficacy useful in
the practice of the present invention include water soluble salts
such as dialkali or tetraalkali metal pyrophosphate salts such as
Na.sub.4P.sub.2O.sub.7 (TSPP), K.sub.4P.sub.2O.sub.7,
Na.sub.2K.sub.2P.sub.2O.sub.7, Na.sub.2H.sub.2P.sub.2O.sub.7 and
K.sub.2H.sub.2P.sub.2O.sub.7. Polyphosphate salts include the water
soluble alkali metal tripolyphosphates such as sodium
tripolyphosphate and potassium tripolyphosphate.
[0032] The pyrophosphate salts are incorporated in the dentifrice
composition of the present invention at a concentration of about
0.5 to about 2.0% by weight, and preferably about 1.5 to about 2%
by weight and the polyphosphate salts are incorporated in the
dentifrice composition of the present invention at a concentration
of about 1.0 to about 7.0% by weight.
[0033] Colorants such as pigments and dyes may be used in the
practice of the present invention. Pigments include nontoxic, water
insoluble inorganic pigments such as titanium dioxide and chromium
oxide greens, ultramarine blues and pinks and ferric oxides as well
as water insoluble dye lakes prepared by extending calcium or
aluminum salts of FD&C dyes on alumina such as FD&C Green
#1 lake, FD&C Blue #2 lake, FD&C R&D #30 lake and
FD&C #Yellow 15 lake. The pigments have a particle size in the
range of 5-1000 microns, preferably 250-500 microns, and are
present at a concentration of 0.5 to 3% by weight.
[0034] Dyes used in the practice of the present invention are
generally food color additives presently certified under the Food
Drug & Cosmetic Act for use in the food and ingested drugs,
including dyes such as FD&C Red No. 3 (sodium salt of
tetraiodofluorescein), FD&C Yellow No. 5 (sodium salt of
4-p-sulfophenylazo-1-p-sulfophenyl-5-hydroxypyrazole-3 carboxylic
acid), FD&C Yellow No. 6 (sodium salt of
p-sulfophenylazo-B-naphtol-6-monosulfonate), FD&C Green No. 3
(disodium slat of
4-{[4-(N-ethyl-p-sulffobenzylamino)-phenyl]-(4-hydroxy-2-sulfoniu-
mphenyl)-mewthylene}-[1-(N-ethyl-N-p-sulfobenzyl)--3,5-cyclohexadienimine]-
, FD&C Blue No. 1 (disodium salt of
dibenzyldiethyldiaminotriphenylcarbino- l trisulfonic acid of
indigotin) and mixtures thereof in various proportions. The
concentration of the dye for the most effective result in the
present invention is present in the dentifrice composition in an
amount from about 0.0005 percent to about 2 percent of the total
weight.
[0035] A striped dentifrice product may be obtained using the dual
component dentifrice embodiment of the present invention, wherein
colorants of contrasting colors are incorporated in each of the
dentifrice components to be dispensed; the colorants being
pharmacologically and physiologically non-toxic when used in the
suggested amounts. Colorants used in the practice of the present
invention include both the pigments and dyes discussed above.
[0036] Any suitable flavoring or sweetening material may also be
incorporated in the dentifrice composition of the present
invention. Examples of suitable flavoring constituents are
flavoring oils, e.g., oils of spearmint, peppermint, wintergreen,
sassafras, clove, sage, eucalyptus, marjoram, cinnamon lemon, and
orange, and methyl salicylate. Suitable sweetening agents include
sucrose, lactose, maltose, sorbitol, xylitol, sodium cyclamate,
perillatine, and sodium saccharin. Suitably, flavor and sweetening
agents may together comprise from 0.01% to 5% or more of the
preparations.
[0037] Antibacterial agents are non-cationic antibacterial agents
based on phenolic and bisphenolic compounds, halogenated diphenyl
ethers such as Triclosan, benzoate esters and carbanilides as well
as cationic antibacterial agents such as chlorhexidine digluconate.
Such antibacterial agents can be present in quantities of from
about 0.03 to about 1% by weight of the particular component.
[0038] When noncationic antibacterial agents or antibacterial
agents are included in any of the dentifrice components, there is
also preferably included from about 0.05 to about 5% of an agent
which enhances the delivery and retention of the agents to, and
retention thereof on oral surfaces. Such agents useful in the
present invention are disclosed in U.S. Pat. Nos. 5,188,821 and
5,192,531; and include synthetic anionic polymeric
polycarboxylates, such as 1:4 to 4:1 copolymers of maleic anhydride
or acid with another polymerizable ethylenically unsaturated
monomer, preferably methyl vinyl ether/maleic anhydride having a
molecular weight (M.W.) of about 30,000 to about 1,000,000, most
preferably about 30,000 to about 800,000. These copolymers are
available for example as Gantrez. e.g. AN 139 (M.W. 500,000), AN
119 (M.W. 250,000) and preferably S-97 Pharmaceutical Grade (M.W.
700,000) available from ISP Technologies, Inc., Bound Brook, N.J.
08805. The enhancing agents when present are present in amounts
ranging from 0.05 to about 3% by weight.
[0039] To prepare the dentifrice components of the present
invention, generally the humectants, for example, propylene glycol,
polyethylene glycol ingredients, are dispersed with any organic
thickeners, sweetener, pigments such as titanium dioxide and any
polyphosphates included as anti-calculus ingredients. Water is then
added into this dispersion along with any antibacterial agent such
as Triclosan, any antibacterial enhancing agent such as Gantrez and
any anticalculus additional agents. In the first neutral pH
component a fluoride ion source desensitizing agent and phosphate
buffering agent is added. In the second component an ingredient to
adjust the pH to an alkaline level is added, such as sodium
hydroxide. These ingredients are mixed until a homogenous phase is
obtained for each component. Thereafter inorganic thickener, silica
abrasive, flavor and surfactant ingredients are added and the
ingredients mixed at high speed under vacuum of from about 20 to
100 mm of Hg. The resultant product, in the case of each component,
is a homogeneous, semi-solid, extrudible paste product.
[0040] The dentifrice composition may be applied to hypersensitive
tooth surfaces in the form of a paste or gel by tooth brushing or
topically applied by being painted directly on the tooth surfaces
in the form of a liquid varnish using a soft applicator brush.
[0041] The single phase dentifrice composition embodiment of the
present invention may be packaged in a single tube or other
conventional package. The multicomponent dentifrice composition
embodiment of the present invention is packaged in a suitable
dispensing container in which the components are maintained
physically separated and from which the separated components may be
dispensed synchronously as a combined ribbon for application to a
toothbrush. Such containers are known in the art. An example of
such a container is a two compartment dispensing container, such as
a pump or a tube, having collapsible sidewalls, as disclosed in
U.S. Pat. Nos. 4,487,757 and 4,687,663; wherein, the tube body is
formed from a collapsible plastic web such as polyethylene or
polypropylene and is provided with a partition within the container
body defining separate compartments in which the physically
separated components are stored and from which they are dispensed
through a suitable dispensing outlet.
[0042] The following example is further illustrative of the present
invention, but it is understood that the invention is not limited
thereto. All amounts and proportions referred to herein and in the
appended claims are by weight, unless otherwise stated.
EXAMPLE I
[0043] A two component (Component A and B) desensitizing dentifrice
of the present invention was prepared, designated "Dentifrice X",
Component A having neutral pH (6.5) and a Component B having an
alkaline pH (9.5). When combined in equal amounts for tooth
brushing, Dentifrice X had a pH of 7.5 in a 1:3 slurry with water.
The ingredients of Components A and B are listed in Table I
below.
1TABLE I Dentifrice X Weight % Component Ingredients A B Deionized
Water 32.995 36.895 Sodium Fluoride 1.105* 1.105* Potassium Nitrate
5.00 5.00 Glycerin 18.000 18.000 Polyethylene glycol 600 3.000
3.000 Xanthan gum 7.000 7.000 Carboxymethyl cellulose 0.500 0.500
Sorbitol 70% NC 5.00 5.000 Sodium saccharin 0.400 0.400 Titanium
Dioxide -- 1.000 Pluronic F-127 2.000 2.000 Sodium Hydroxide (50%)
-- 1.000 Sodium Phosphate Mono 4.000 -- Sodium Phosphate Dibasic
3.500 -- FD&C Blue #1 (1.25% solution) -- 0.300 Zeodent 115
20.000 15.000 Zeodent 165 1.000 1.500 Sodium bicarbonate -- 2.500
N-silicate -- 3.800 Sodium lauryl sulfate 1.500 1.500 Flavor 1.100
1.100 *Releases 5000 ppm fluoride ion
[0044] In the preparation of Dentifrice X, components A and B were
prepared wherein the glycerin, polyethylene glycol and organic
thickeners were dispersed in a conventional mixer until the mixture
became a slurry, which was smooth in appearance. Color and
sweetener were dispersed in this slurry before the addition of
water. In the preparation of Component A, potassium nitrate was
then dispersed in this slurry. In the preparation of Component B,
sodium hydroxide was then dispensed in the gel phase. This mixture
was mixed for 20 to 30 minutes producing a homogeneous gel phase.
The mixture was added to a vacuum mixer and cooled below
105.degree. F. Zeodent 115, Zeodent 165 and sodium bicarbonate were
then added and mixed for 10 to 30 minutes at high speed under a
vacuum of about 50 mm Hg, providing a homogenous mixture. The
sodium lauryl sulfate and flavor were then added to the individual
dentifrice components which was followed by mixing another 5-15
minutes under vacuum of 50 mm Hg to prepare the resultant component
product.
[0045] The desensitizing efficacy of the two component Dentifrice X
was evaluated using 4.25 mm.times.4.25 mm square dentin disks of
750 .mu.m thickness cut from extracted human molars. The disks were
prepared for treatment by etching with 6% citric acid for 2 minutes
to remove any surface smear.
[0046] For purposes of comparison the procedure of the Example I
was repeated with another group of similarly prepared disks using a
dual component dentifrice designated "Dentifrice Y", comparable to
that of U.S. Pat. No. 6,180,089 in which the alkaline component
designated "Component C" had a pH of 9.5 and the acidic component
designated "Component D" had a pH of 5.2. The ingredients of
Components C and D of Dentifrice Y are listed in Table II
below.
[0047] As a control, the procedure of the Example was repeated
using a phosphate buffer solution as the treatment which treatment
was designated "Control". The ingredients of the phosphate buffer
solution are listed in Table III below.
[0048] The ingredients of Components C and D of Dentifrice Y are
listed in Table II below.
2TABLE II Dentifrice Y Component C Component D Ingredient %
Ingredient % Deionized water 29.57 Dionized water 25.66 Potassium
nitrate 10.000 Anhydrous citric acid 0.531 Glycerin 25.48 Sodium
citrate 2.657 PEG 600 3.00 Stannous chloride 0.600 Xanthan NF 0.700
Stannous fluoride 0.908* Sodium carboxymethyl 0.50 Glycerin 33.704
cellulose Sodium saccharin 0.4 Xanthan 0.500 Titanium dioxide 2.00
Sodium carboxymethyl 0.700 cellulose 2000S Pluoronic F-127 1.00
Sodium saccharin 0.400 Zeodent 115 15.00 Tetrasodium pyrophosphate
0.500 Zeodent 165 1.75 FD&C Blue #1 0.240 (1.25% soln.) Sodium
bicarbonate 5.00 PEG 40 oil 6.00 Sodium hydroxide 3.00 Pluoronic
F-127 2.00 Flavor stannous plus 1.10 Zeodent 115 20.00 Sodium
lauryl sulfate 1.5 Zeodent 165 3.00 Flavor 1.100 Sodium lauryl
sulfate 1.500 Totals 100 100 *Releases 2200 ppm fluoride ion.
Fluoride ion delivery of Dentifrice Y is 1100 ppm when Component C
and D are combined for use.
[0049]
3TABLE III Phosphate Buffer Solution Ingredient Wt. % Millimoles
Sodium phosphate mono 0.0087 0.63 CaCl.sub.2 1.1456 1.06 NaCl 0.877
150.0
[0050] The etched disks were then treated by separately brushing
the discs for a 60 second period with either Dentifrice X or Y or
the phosphate buffer solution (control).
[0051] The surface composition of the treated disks were then
subjected to Electron Spectroscopy for Chemical Analysis (ESCA) and
Scanning Electron Microscopy (SEM) analysis. The ESCA results are
recorded in Table IV below as an average for each group. The
percentage of nitrogen on the dentin surface is generally
attributed to the amount of exposed collagen material which is an
integral part of the dentin structure. The reduced amount of
nitrogen is indicative of a surface coating, and the higher the
amount of calcium ion, the greater the degree of tubular
occultation.
4TABLE IV ESCA Analysis Atomic Percent Dentifrice C O N Ca P Si Na
Sn F P/Ca Ration X 33.20 42.63 3.78 7.66 6.32 4.88 0.80 0.19 0.55
0.82 Y 27.76 47.27 2.45 4.73 4.10 11.39 1.02 1.16 0.11 0.86 Control
59.69 22.78 14.72 1.17 0.99 0.68 -- -- -- 0.85
[0052] The results recorded in Table IV indicate that the amount of
deposit formed on the surface of the dentin disks treated with the
combined components of Dentifrice X of the present invention is
substantially greater than the disks treated with comparative
Dentifrice Y, indicating a significantly greater degree of tubular
obturation would be experienced with the use of Dentifrice X as
compared to Dentifrice Y.
[0053] The SEM photomicrographs taken of the dentin surfaces
subjected to the brushing treatments are shown in FIGS. 1-3
respectively. Examination of the SEM of the Dentifrice X treated
dentin disk surface, (FIG. 1), indicates that dentinal tubule
obturation was substantially complete as compared to treatment with
comparative dual component Dentifrice Y as indicated by examination
of the photomicrograph of FIG. 2. The Control treatment of the
dentin disks using an phosphate buffer solution as shown in the SEM
of FIG. 3 indicates a limited amount of dentinal tubule
obturation.
[0054] The ESCA and the SEM results all provide evidence that the
unique combination of the neutral and alkaline potassium ion
containing dentifrice components in combination with high
releasable fluoride ion concentration levels effects an unexpected
significant improvement in the remediation of dentinal
hypersensitivity.
Example II
[0055] A single component dentifrice designated Dentifrice Z was
prepared which contained the ingredients listed in Table V below.
The dentifrice composition has a pH of 8.5.
5 TABLE V Ingredients Dentifrice Z (Wt. %) Deionized Water 34.345
Sodium Fluoride 1.105* Potassium Nitrate 5.00 Glycerin 18.000
Polyethylene glycol 600 3.000 Xanthan gum 0.7000 Carboxymethyl
cellulose 0.500 Sorbitol 70% NC 5.00 Sodium saccharin 0.400
Pluronic F-127 2.000 Sodium phosphate mono 2.0 Sodium phosphate
diabasic 1.75 FD&C Blue #1 (1.25% solution) 0.2 Zeodent 115
17.5 Zeodent 165 1.25000 Sodium Bicarbonate 1.75 Sodium lauryl
sulfate 1.500 Flavor 1.100 *Releases 5000 ppm fluoride ion
[0056] In-Vitro Remineralization/Demineralization Test with
Fluoride Uptake
[0057] Specimen Preparation
[0058] An in vitro fluoride uptake test method using enamel
specimens (3 mm diameter) removed from extracted human teeth and
mounted in rods to evaluate the performance of Dentifrice 2. The
specimens were ground and polished to a high luster with Gamma
Alumina using standard methods. Eighteen specimens per group were
prepared for this study.
[0059] Initial Decalcification
[0060] Artificial lesions were formed in the enamel specimens by a
96-hour immersion into a solution of 0.1 M lactic acid and 0.2%
Carbopol C907 which was 50% saturated with hydroxyapatite and
adjusted to pH 5.0. The lesion surface hardness range was 25-45 and
average lesion depth was approximately 70.mu..
[0061] Saliva Collection
[0062] A 50:50 mixture of pooled, human saliva and a mineral
solution was used as the remineralization medium in all treatment
regimens. Wax-stimulated saliva was collected from at least five
individuals and refrigerated until used. Saliva samples were then
pooled with vigorous stirring prior to distribution (7.5 ml+7.5 ml
mineral mix) into 30 ml treatment beakers. Fresh saliva/mineral mix
was used each day (changed during the acid challenge period).
[0063] Treatment Slurries
[0064] During the treatment period, the specimens were immersed in
dentifrice slurries to simulate daily brushing. The slurries were
prepared by adding 5.0 g of dentifrice to 10 g of the fresh
saliva/mineral mix solution in a beaker with a magnetic stirrer. A
fresh slurry was prepared just prior to each treatment.
[0065] Treatment Regimen
[0066] The cyclic treatment regimen consisted of a 4.0 hour/day
acid challenge in the lesion forming solution described above with
four, one-minute dentifrice treatment periods. After the
treatments, the specimens were rinsed with running distilled water
and then replaced back into the saliva. The remaining time (about
20 hours) the specimens were in the pooled, human saliva,
remineralization system. The regimen was repeated for 20 days. The
treatment schedule used was as follows:
6 a. 8:00-8:01 a.m. Dentifrice treatment* b. 8:01-9:00 a.m. Saliva
treatment c. 9:00-9:01 a.m. Dentifrice treatment d. 9:01-10:00 a.m.
Saliva treatment e. 10:00 a.m.-2:00 p.m. Acid challenge f.
2:00-3:00 p.m. Saliva treatment g. 3:00-3:01 p.m. Dentifrice
treatment h. 3:01-4:00 p.m. Saliva treatment i. 4:00-4:01 p.m.
Dentifrice treatment j. 4:01 p.m.-8:00 a.m. Saliva treatment k.
Back to (a)
[0067] Fluoride Analysis
[0068] At the end of the 20-day treatment regimen, the fluoride
content of each enamel specimen was determined using the microdrill
technique to a depth of 100.mu.. Fluoride data were calculated as
.mu.g F/cm.sup.3: (.mu.g F.times.dilution factor-volume of
drilling). The results of the fluoride analysis are recorded in
Table VI below.
[0069] For purposes of comparison, a phase dentifrice designated
"Composition C", which had a fluoride ion content of 5000 ppm in
which potassium nitrate was absent was also tested for fluoride ion
uptake. Composition C had a pH of 7.5. The fluoride uptake for
Composition C is also recorded in Table VI.
7TABLE VI Fluoride Uptake Assay Results Fluoride ion Dentifrice
Uptake ug/cm.sup.3) Standard Deviation Z 8128 .+-.131 C 1987
.+-.341
[0070] The fluoride uptake data recorded in Table VI indicate that
the single phase composition that contained 5% potassium nitrate in
which the pH was 9.0 unexpectedly deposited substantially more
fluoride ion about four times as much than a comparative single
phase composition in which the pH was 8.0 and potassium nitrate was
not present in the dentifrice.
[0071] Dentifrice Z was tested in vitro for in situ
remineralization of caries lesions in employing the methodology
described below.
[0072] Remineralization Measurements
[0073] Following fluoride analysis discussed above all samples were
tested for surface hardness changes. The difference between the
hardness following treatment and initial lesion hardness indicated
the ability of that treatment to enhance remineralization.
[0074] Determination of Enamel Resistance to Demineralization
[0075] The resistance of the treated enamel to a subsequent acid
challenge was determined by placing the treated specimens into the
lesion formation solution (with no remineralization phase) for one
2-hour and one 16-hour period of simulated plaque acid challenge
(SPAC). Following each acid challenge, the surface hardness of the
specimens was measured as a Vickers Hardness Number (VHN) using a
Leite Microhardness tester. The difference between the hardness
following each subsequent demineralization and the initial lesion
hardness reflected the degree of resistance to demineralization
provided by each dentifrice.
[0076] Results of the remineralization tests of Dentifrice Z are
recorded in Table VII below.
[0077] For purposes of comparison a toothpaste product designated
Dentifrice D having a composition substantially similar to
Dentifrice Z except that potassium nitrate was not included in
Dentifrice D was also tested for remineralization efficacy. The pH
of Dentifrice D was 7.5. The remineralization results for
Dentifrice D are also recorded in Table VII below.
8TABLE VII Enamel Hardness Composition .DELTA.VHN Z 133 .+-. 8 D 21
.+-. 4
[0078] The desensitizing efficacy of Dentifrice Z was evaluated
following the procedure of Example I.
[0079] For purposes of comparison the procedure of the Example I
was repeated with another group of similarly prepared disks using a
dentifrice designated "Dentifrice E". Dentifrice E differed from
Dentifrice Z in that the fluoride content was 1100 ppm Fluoride and
did not contain phosphate buffering salts.
[0080] Electron Spectroscopy for Chemical Analysis (ESCA) and
Scanning Electron Microscopy (SEM) analysis results are recorded in
Table VIII below.
9TABLE VIII ESCA ANALYSIS Atomic Percent Dentifrice C O N Ca P Si
Na Sn F Ratio P/Ca E 33.05 42.46 5.75 3.81 3.14 10.19 0.70 0.82
0.09 0.83 Z 32.06 43.37 1.14 10.78 8.68 2.10 0.96 -- 0.93 0.81
[0081] The results recorded in Table VIII indicate that the amount
of Ca and deposited on the surface of the dentin disks treated with
Dentifrice Z of the present invention was significantly greater,
that is, three times greater than the disks treated with
comparative Dentifrice E, indicating a significantly greater degree
of tubular obturation would be experienced with the use of
Dentifrice Z as compared to Dentifrice E.
* * * * *