U.S. patent application number 11/927636 was filed with the patent office on 2008-06-05 for methods of whitening teeth.
This patent application is currently assigned to BRITESMILE PROFESSIONAL, LLC. Invention is credited to R. Eric Montgomery.
Application Number | 20080131380 11/927636 |
Document ID | / |
Family ID | 21709918 |
Filed Date | 2008-06-05 |
United States Patent
Application |
20080131380 |
Kind Code |
A1 |
Montgomery; R. Eric |
June 5, 2008 |
Methods of Whitening Teeth
Abstract
The present invention relates to improved dental compositions
and methods for bleaching teeth. More specifically, this invention
is directed towards hydrogen peroxide-containing compounds that are
maintained at a substantially constant pH range of 6.0-10.0 during
the tooth-bleaching procedure in the presence of a calcium
chelating agent.
Inventors: |
Montgomery; R. Eric;
(Monterey, MA) |
Correspondence
Address: |
DISCUS DENTAL, LLC
8550 HIGUERA STREET
CULVER CITY
CA
90232
US
|
Assignee: |
BRITESMILE PROFESSIONAL,
LLC
Culver City
CA
|
Family ID: |
21709918 |
Appl. No.: |
11/927636 |
Filed: |
October 29, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11256654 |
Oct 21, 2005 |
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11927636 |
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09192609 |
Nov 16, 1998 |
6331292 |
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11256654 |
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08719569 |
Sep 25, 1996 |
5922307 |
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09192609 |
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60004258 |
Sep 25, 1995 |
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Current U.S.
Class: |
424/53 |
Current CPC
Class: |
A61Q 11/02 20130101;
A61K 8/22 20130101; A61K 8/19 20130101; A61K 8/55 20130101; A61K
2800/51 20130101; A61K 2800/88 20130101; A61K 2800/52 20130101;
A61K 8/8147 20130101; A61K 8/44 20130101; A61K 8/365 20130101; A61Q
11/00 20130101; A61K 8/41 20130101; A61K 8/24 20130101 |
Class at
Publication: |
424/53 |
International
Class: |
A61K 8/22 20060101
A61K008/22; A61Q 11/00 20060101 A61Q011/00 |
Claims
1-12. (canceled)
13. A method for whitening teeth with a whitening composition
comprising: dispensing a whitening composition comprising hydrogen
peroxide, a thickening agent, a pH adjusting agent, a calcium
chelating agent into a dental tray; positioning said dental tray
over a patient's teeth such that said whitening composition is in
constant contact with said patient's teeth; and leaving said dental
tray in place over said patient's teeth for at least 20 minutes;
wherein said whitening composition has a pH greater then 5.5 and
said process is repeated at least twice a day.
14. The method for whitening teeth of claim 13, wherein said
whitening composition is dispensed from a single exit
multi-component tube containing a static mixing baffle into said
dental tray.
Description
RELATED U.S. APPLICATION(S)
[0001] This application is a continuation of U.S. patent
application Ser. No. 11/256,654, filed on Oct. 21, 2005, which
application is a continuation of U.S. application Ser. No.
09/192,609, filed on Nov. 16, 1998, itself a divisional of U.S.
application Ser. No. 08/719,569, filed on Sep. 25, 1996, which
issued on Jul. 13, 1999 as U.S. Pat. No. 5,922,307, and which
claims priority from Provisional Application Ser. No. 60/004,258,
filed Sep. 25, 1995, all of which are hereby incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present invention relates to improved dental bleaching
compositions and methods for bleaching teeth.
BACKGROUND ART
[0003] White teeth have long been considered cosmetically
desirable. Unfortunately, teeth become almost invariably discolored
in the absence of intervention. The tooth structures which are
generally responsible for presenting a stained appearance are
enamel, dentin, and the acquired pellicle. Tooth enamel is
predominantly formed from inorganic material, mostly in the form of
hydroxyapatite crystals and further contains approximately 5%
organic material primarily in the form of collagen. In contrast,
dentin is composed of about 20% protein including collagen, the
balance consisting of inorganic material, predominantly
hydroxyapatite crystals, similar to that found in enamel. The
acquired pellicle is a proteinaceous layer on the surface of tooth
enamel which reforms rapidly after an intensive tooth cleaning.
[0004] Staining of teeth results from extrinsic and/or intrinsic
staining. Extrinsic staining of the acquired pellicle arises as a
result of compounds such as tannins and polyphenolic compounds
which become trapped in and tightly bound to the proteinaceous
layer on the surface of the teeth. This type of staining can
usually be removed by mechanical methods of tooth cleaning. In
contrast, intrinsic staining occurs when staining compounds
penetrate the enamel and even the dentin or arise from sources
within the tooth. This type of staining is not amenable to
mechanical methods of tooth cleaning and chemical methods are
required.
[0005] Consequently, tooth-bleaching compositions generally fall
into two categories: (1) gels, pastes, or liquids, including
toothpastes that are mechanically agitated at the stained tooth
surface in order to affect tooth stain removal through abrasive
erosion of stained acquired pellicle; and (2) gels, pastes, or
liquids that accomplish the tooth-bleaching effect by a chemical
process while in contact with the stained tooth surface for a
specified period, after which the formulation is removed. In some
cases, the mechanical process is supplemented by an auxiliary
chemical process which may be oxidative or enzymatic.
[0006] The majority of professionally-monitored at-home
tooth-bleaching compositions act by oxidation. These compositions
are dispensed directly to a patient for use in a custom-made
tooth-bleaching tray, held in place in the mouth for contact times
of greater than about 60 minutes, and sometimes as long as 8 to 12
hours. The slow rate of bleaching is in large part, the consequence
of formulations that are developed to maintain stability of the
oxidizing composition. The most commonly used oxidative
compositions contain the hydrogen peroxide precursor carbamide
peroxide which is mixed with an anhydrous or low-water content,
hygroscopic viscous carrier containing glycerine and/or propylene
glycol and/or polyethylene glycol. When contacted by water,
carbamide peroxide dissociates into urea and hydrogen peroxide.
Associated with the slow rate of bleaching in the hygroscopic
carrier, the currently available tooth-bleaching compositions cause
tooth sensitization in over 50% of patients. Tooth sensitivity is
believed to result from the movement of fluid through the dentinal
tubes toward nerve endings in the tooth. This movement is enhanced
by the carriers for the carbamide peroxide. In fact, it has been
determined that glycerine, propylene glycol and polyethylene glycol
can each give rise to varying amounts of tooth sensitivity
following exposure of the teeth to heat, cold, overly sweet
substances, and other causative agents.
[0007] Prolonged exposure of teeth to bleaching compositions, as
practiced at present, has a number of adverse effects in addition
to that of tooth sensitivity. These include: solubilization of
calcium from the enamel layer at a pH less than 5.5 with associated
demineralization; penetration of the intact enamel and dentin by
the bleaching agents, so as to reach the pulp chamber of a vital
tooth thereby risking damage to pulpal tissue; and dilution of the
bleaching compositions with saliva with resulting leaching from the
dental tray and subsequent digestion.
[0008] The stability of existing formulations of hydrogen
peroxide-containing tooth-bleaching compositions in terms of
shelf-life as well as over the period of use in the mouth, depends,
in general, or an acidic pH. The hydrogen peroxide becomes markedly
less stable as the pH increases. Indeed, Frysh, et al. (Journal of
Esthetic Dentistry Vol. 7, No. 3, pp. 130-133, 1995) described the
use of high concentration (35%) of hydrogen peroxide solutions at
an initial alkaline pH, which was required to be formulated
immediately before use and was administered in the form of a liquid
to extracted teeth to achieve tooth bleaching. Phillips and Bowles
(IADR Abstract J. Dent. res 75, 1996) have demonstrated that
hydrogen peroxide penetrates the enamel of extracted teeth less
readily over a 15 minute period at pH 9.0 than at pH 4.5. Carbamide
peroxide compositions have been formulated at a pH of 5.0-6.5 using
hygroscopic carriers and maintaining a low water content. This type
of formulation is problematic with regard to enhanced tooth
sensitivity. On contact with saliva, the water content of the
formulation increases, causing the carbamide to disassociate into
urea and hydrogen peroxide and the pH to be decreased. In fact, the
equilibrium pH of a 10% carbamide peroxide solution is
approximately 3.45 and a typical commercially-available
tooth-bleaching gel with 10% carbamide peroxide when combined with
saliva in a 1:1 weight ratio has an initial pH of 5.6 and gradually
decreases to pH 4.8 after 8 hours.
[0009] Thus, currently available tooth-bleaching compositions that
rely on hydrogen peroxide as oxidizing agents, all release hydrogen
peroxide from precursors at low pH levels despite the low rates of
tooth-bleaching activity.
[0010] There is a need for a home use tooth-bleaching product that
is stable, easy to use, and rapid-acting that utilizes reduced
amounts of hydrogen peroxide and is capable of administration to a
patient by means of a dental tray. There is a further need for a
tooth-bleaching composition that may reduce hand soft tissue
irritation, tooth sensitivity, and bleaching composition ingestion
to further increase patient compliance.
SUMMARY OF THE INVENTION
[0011] The invention satisfies the above needs. An embodiment of
the invention includes a tooth-bleaching composition for contacting
a tooth surface in a subject that includes a hydrogen
peroxide-containing compound. Furthermore the composition includes
a matrix for administering the hydrogen peroxide-containing
compound to the tooth surface. The matrix comprises a thickening
agent, an agent for stabilizing the hydrogen peroxide-containing
compound, a pH adjusting agent and a calcium chelating agent,
wherein the pH of the tooth-bleaching composition during the
bleaching process is substantially constant with a range of pH
6.0-10.
[0012] A further embodiment of the invention includes a dosage
delivery unit for tooth bleaching, including a multi-chamber vessel
wherein each chamber is responsive to an applied pressure from an
external source, such that a mixture of reagents contained within a
compartment including a hydrogen peroxide containing composition
and a matrix, will be forced to exit the compartment through a
mixing baffle in response to the externally applied pressure.
[0013] A further embodiment of the invention includes a method for
bleaching teeth including preparing a composition as described
above and administering the composition to the tooth surface.
DETAILED DESCRIPTION OF THE INVENTION
[0014] The present invention comprises compositions and methods for
bleaching tooth enamel in situ which allow the use of reduced
concentrations of hydrogen peroxide in tooth-bleaching compositions
in order to achieve effective tooth bleaching in a contact time of
less than one hour.
[0015] The tooth surface is defined here and in the claims as a
portion of a tooth which is directly responsible for the stained
appearance of said tooth. The term tooth surface generally means a
tooth's acquired pellicle, plaque, enamel, and combinations
thereof.
[0016] The matrix is defined here and in the claims as the gel,
paste, or liquid in which the hydrogen peroxide containing compound
is placed for administration to the subject.
[0017] The subject referred to here and in the claims is commonly a
human subject but also includes domestic animals.
[0018] An important aspect of the present invention is the finding
that the efficiency of the bleaching reaction in a tooth using a
chemical tooth-bleaching agent such as hydrogen peroxide can be
significantly enhanced at a pH greater than 5.5, more particularly
a pH in the range of 6-10, for example in a range of pH of 7-10,
more particularly between 8.0 and 9.5, providing that the pH is
maintained at a substantially constant range throughout the
tooth-bleaching process and a calcium chelating agent is included
in the composition to prevent precipitation of calcium ions. (Table
1-4)
[0019] Suitable pH adjusting agents include, but are not limited
to, sodium hydroxide, potassium hydroxide, ammonium hydroxide,
sodium carbonate, potassium carbonate, TRIS and
triethanolamine.
[0020] Examples of calcium chelating agents include any of the
calcium chelating agents known in the art. Examples include EDTA
and its salts, citric acid and its salts, gluconic acid and its
salts, alkali metal pyrophosphates and alkali metal polyphosphates.
The use of citric acid, sodium acid pyrophosphates and disodium
EDTA are shown in Table 1 and Table 2. The biological efficacy of
sodium acid pyrophosphate is shown in Table 4. Without being bound
to any particular theory, it is proposed that calcium precipitation
in the form of calcium phosphates arise in the intercrystalline
interstices of the tooth at elevated pHs and this gives rise to a
blockage of movement of the peroxide into the tooth with resulting
negative effect on tooth bleaching. Calcium chelating agents may
prevent this precipitation of calcium ions with the associated
observed improvement of tooth-bleaching effect.
[0021] The composition may also contain a stabilizing agent for
removing from solution, metal ions that interfere with the action
of the hydrogen peroxide. In certain formulations, a single
component may act either as a calcium chelating agent or as a
stabilizing agent or may serve both functions.
The ability to maintain constant pH range above 5.5 throughout the
period of tooth bleaching coupled with the inhibition of calcium
precipitation that normally occurs at pH levels above 5.5, has
resulted in a formulation that is suitable for use in the home and
is capable of achieving detectable tooth bleaching in less than 30
minutes. Furthermore, multiple treatments (each treatment lasting
no longer than 30 minutes) have been demonstrated to substantially
whiten teeth (Example 5). In Example 5, 14 treatments using the
inventive formulation, were administered for twenty minutes, twice
a day, over seven days. A mean .DELTA.E of 7.32 was observed
denoting a substantial tooth-bleaching effect compared with a
.DELTA.E of 4.73 using a prior art formulation for a period of time
that was three times longer than that of the novel formulation.
[0022] According to the invention, additional agents having
tooth-bleaching effect may be used to achieve detectable tooth
bleaching in less than 30 minutes. For example, sodium percarbonate
has been demonstrated to be very effective at tooth bleaching when
maintained at a pH that is greater than 5.5, more preferably in the
range of 7-10, more particularly 8-9.5 that includes a calcium
chelating agent. This composition differs from carbamide peroxide
in that there is no acidification of that solution that results
upon its dissociation. Consequently, the reagent may be maintained
at a constant elevated pH for an extended period of time without
the necessity for adding buffering reagents beyond that naturally
supplied in the saliva. Unlike carbamide peroxide, however the
percarbonate is prepared in a formulation that does not include
glycerine and is only slowly permeated by water whereupon hydrogen
peroxide is released. For this reason, it may be desirable, but is
not essential, to prepare the percarbonate in a two-component
composition, the two components being mixed before use so as to
accelerate the tooth-bleaching effect (Examples 1 and 2).
Formulations containing two components may be applied to the dental
tray by squeezing a tube in much the same way as a single
component. The mixing of the two components can be readily achieved
using a multi-component tube containing a baffle, otherwise known
in the art as a static mixer such that on squeezing the tube,
material from each of the compartments is forced through the static
mixer and are mixed together before emerging from single exit in
the tube.
[0023] The present invention has important health benefits that
follow from shorter contact times of the tooth with hydrogen
peroxide as well as the need for lower concentrations of peroxide
to achieve a desired tooth-bleaching effect.
EXAMPLE 1
Composition of a Stable Tooth-Bleaching Formulation Suitable for
Use in a One Component System
[0024] The formulations below utilized ultrapure components to
avoid destabilization caused by metal ion contaminants. The
chelating agent used here is one of disodium EDTA (1C) citric acid
(1B), and sodium acid pyrophosphate (1F). The pH is modified using
one of sodium hydroxide monohydrate (1A, 1B, 1C), ammonium
hydroxide (1F,IG), Tris(hydroxymethyl) aminomethane (1D), and
triethanolamine (1E). Carbopol is a high molecular weight
crosslinked polyacrylic acid thickening agent. Hydrogen peroxide is
used as the oxidizing agent.
TABLE-US-00001 TABLE 1 Example 1 A B C D E F G Ingredient WEIGHT
PERCENT Distilled Water 86.41 86.21 86.31 72.80 79.52 86.50 73.81
1-Hydroxyethylidene-1,1- 0.02 0.02 0.02 0.03 0.02 0.30 0.40
diphosphonic acid Sodium stannate 0.02 0.02 0.02 0.03 0.02 0.05
0.05 trihydrate Citric Acid -- 0.20 -- -- -- -- 0.10 Calcium
disodium EDTA -- -- 0.10 -- -- -- -- Sodium acid -- -- -- -- --
0.30 -- pyrophosphate Hydrogen Peroxide 35% 10.30 10.30 10.30 17.14
17.14 8.60 17.14 Carbopol 974P (BF 2.50 2.50 2.50 5.00 -- 3.00 5.00
Goodrich) Carbopol 934P (BF -- -- -- -- 2.00 -- -- Goodrich) Sodium
Hydroxide to pH 7.0 to pH 7.0 to pH 7.0 -- -- -- -- Monohydrate
Ammonium hydroxide -- -- -- -- -- to pH 6.5 to pH 8.5 28%
Tris(hydroxymethyl) -- -- -- to pH 8.0 -- -- -- aminomethane
Triethanolamine -- -- -- -- to pH 6.0 -- -- Total 100 100 100 100
100 100 100 pH @ 25 deg. C. 7.0 7.0 7.0 8.0 6.0 6.5 8.5
[0025] The above formulations were prepared by dissolving the
stabilizers 1-hydroxyethylidene-1,1-diphosphonic acid and the
sodium stannate trihydrate in the distilled water using a
Kynar-coated propeller-type agitator (reserving enough water, if
necessary, to dissolve the neutralizer in the final step). The
hydrogen peroxide was then added slowly to this mixture. The
Carbopol 974P was then added to the distilled,
water/stabilizer/hydrogen peroxide mixture slowly while a vortex
was formed with the agitator blade. This dispersion was then placed
in a Kynar-coated vacuum double planetary mixer to which the pH
adjusting agent was added slowly to affect neutralization of the
Carbopol 974P and to adjust the final composition pH. The resulting
composition was a transparent viscous gel and was packaged in
foil/plastic laminate tubes having a polyethylene product contact
liner.
EXAMPLE 2
A Two Component Alkaline Tooth-Bleaching Formulation
[0026] A hydrogen peroxide-releasing composition was formulated
which utilized sodium percarbonate in an anhydrous gel, and was
designed to be combined with a separate aqueous gel prior to use in
order to dissolve the sodium percarbonate to form hydrogen peroxide
and sodium carbonate. The pH of this composition, shown in Table 2,
when combined in a volume ratio of 1 to 1, was 9.0. The chelating
agents used here are EDTA and sodium acid pyrophosphate.
TABLE-US-00002 TABLE 2 EXAMPLE 2 PART A PART B INGREDIENT WEIGHT
PERCENT Distilled Water -- 95.20 Polyethylene glycol 400 83.00 --
Sodium percarbonate (powder) 12.00 -- EDTA -- 0.20 Sodium acid
pyrophosphate -- 0.30 Carbopol 974P (Goodrich) 2.50 4.00 Sodium
Hydroxide Monohydrate -- to pH 7.0 Tris(hydroxymethyl)aminomethane
2.50 -- Total 100 100
[0027] The above composition parts were prepared as follows:
[0028] Part A--The Carbopol was dispersed in the polyethylene
glycol using a propeller-type agitator with Kynar-coated product
contact surfaces. The resulting dispersion was added to a
Kynar-coated vacuum double planetary mixer (as in Example 1) and
neutralized with the tris(hydroxymethyl)aminomethane under low
shear mixing. To the resultant neutralized Carbopol gel, sodium
percarbonate was added and dispersed until the composition was a
homogenous white paste.
[0029] Part B--The Carbopol was added to the water (in the EDTA and
sodium acid pyrophosphate had already been dissolved) and agitated
as above. The resulting dispersion was transferred to the
Kynar-coated vacuum double planetary mixer and neutralized with the
sodium hydroxide monohydrate under low shear mixing. The final gel
was clear and viscous, with a pH of around 7.0.
EXAMPLE 3
Preparation of a Tooth-Bleaching Formulation Having Acidic pH
[0030] In order to demonstrate the superior ability of the
inventive hydrogen peroxide gel composition of Examples 1 and 2 to
bleach teeth, a composition was prepared which was similar to that
of Example 1E, except that the pH was adjusted to 4.5.
TABLE-US-00003 TABLE 3 INGREDIENT PERCENT Distilled water 79.82
1-Hydroxyethylidene-1,1-diphosphonic acid 0.02 Sodium stannate
trihydrate 0.02 Carbopol 974P 2.00 Hydrogen Peroxide 35% 17.14
Triethanolamine 1.00 TOTAL 100.00
[0031] The formulation was prepared as in Example 1, resulting in a
transparent, viscous gel with a pH of approximately 4.5. The
formulation is similar to 1E, the difference lying in the pH of the
composition.
EXAMPLE 4
Assay to Determine Tooth Bleaching
[0032] Bovine incisors, which had been imbedded in an acrylic
matrix such that the buccal surfaces presented themselves on the
top surface, were stained in a manner to duplicate the tooth
staining observed in vivo by humans (alternately exposed to air and
a staining broth at 37 degrees C. containing typticase soy broth,
tea, coffee, mucin, FeCl.sub.3 and Sarcina lutea, for a period of
about four days). Each stained bovine incisor was numbered and
measured for degree of staining (color by the CIELAB protocol) with
a Minolta 5031 Spectrophotometer (3 mm aperture, 8 exposure
averaging, outliers discarded.). Incisors were covered with
different tooth-bleaching compositions in the tables above, in
addition to a commercially available carbamide peroxide composition
(Opalescence 10% Carbamide Peroxide Gel, Ultradent, South Jordan,
Utah). All gels were kept in contact with the incisor surface for
exactly 15 minutes, whereupon the tooth was rinsed clean of any gel
residue with distilled water and swabbed with saliva. The degree of
stain removal was thereafter immediately determined by measuring
the incisor surface, as above, for color, and the change in tooth
color recorded below as .DELTA.E. Absolute color change is defined
as the square root of the sum of the squares of all color
components (L, a, and b).
{square root over
([(.DELTA.L).sup.2+(.DELTA.a).sup.2+(.DELTA.b).sup.2])}{square root
over ([(.DELTA.L).sup.2+(.DELTA.a).sup.2+(.DELTA.b).sup.2])}{square
root over
([(.DELTA.L).sup.2+(.DELTA.a).sup.2+(.DELTA.b).sup.2])}=.DELTA.E
TABLE-US-00004 TABLE 4 pH Initial Color Final Color Tooth #
Product/Example (neat) L a b L a b .DELTA.E 1 Opalescence 6.5 41.79
3.17 11.78 44.29 2.96 11.70 2.51 2 Example 3 4.5 39.84 4.99 12.00
43.96 4.47 10.94 4.29 3 1E 6.0 40.44 4.41 9.53 46.32 3.48 7.54 6.27
4 1A 7.0 36.02 3.84 10.10 42.57 2.59 8.28 6.91 5 1B 7.0 38.81 3.98
11.38 45.92 2.38 8.81 7.73 6 1C 7.0 36.90 4.05 12.61 44.11 2.45
10.53 7.67 7 1D 8.0 41.55 3.67 10.51 49.77 1.26 7.82 8.98 8 1F 6.5
38.55 5.01 10.87 44.78 3.67 9.50 6.52 9 1G 8.5 40.26 4.59 9.93
48.28 3.13 7.97 8.38 10 Example 2 9.0 36.49 4.00 12.64 44.93 2.20
10.63 8.78
[0033] This table shows the effect of pH on tooth bleaching. As
shown for tooth #2 with the formulation of Example 3 and tooth #3
treated with the formulation of 1E in Example 1, the increase in pH
from 4.5 (2) to 6.0 (3) results in an increased .DELTA.E from 4.29
to 6.27.
[0034] The table further shows the positive effect of the calcium
chelating agent on tooth bleaching. For example, for 1A, 1B, and 1C
(all at pH 7.0), 1A lacked a calcium chelating agent whereas 1B and
1C contained a chelating agent. There was an observed improvement
in .DELTA.E in the presence of the chelating agent. The best
tooth-bleaching results were obtained at the highest pH, namely, in
this experiment, pH 8.0 and pH 9.0.
[0035] Opalescence is a commercial product which has been pH
adjusted to pH 6.5 before use but shows a poor performance with
regard to color change over time of the experiment. It is proposed
that the pH of the formulation is lowered as hydrogen peroxide and
urea is released following dissociation of carbamide peroxide.
EXAMPLE 5
In Vivo Demonstration of Tooth Bleaching
[0036] Six volunteers aged 25 to 43 were separated into two groups
of two and custom dental trays were fashioned for each
participant.
[0037] One group was given an unmarked 2 oz. tube containing the
composition of Example 1B and instructed to place a small amount of
tooth-bleaching material into the tray, position the tray over the
teeth, and leave the tray in place for 20 minutes. Patients were
instructed to repeated this procedure twice a day for one week, for
a total of 14 treatments and 280 minutes total tooth whitener
exposure time.
[0038] The second group was given an unmarked 2 oz. tube of
Opalescence 10% Carbamide Peroxide tooth-bleaching gel and
instructed as above, with the exception of the duration of the
bleaching procedure twice a day for one week, for a total of 14
treatments and 840 minutes total tooth-bleaching exposure time.
[0039] The results of direct tooth surface (upper left central
incisor) color measurements, both before and after treatment (as in
Example 5 above), are recorded in the Table 5 below.
TABLE-US-00005 TABLE 5 Treatment Initial Color Final Color Patient#
Product/Example Time (minutes) L a b L a b .DELTA.E 1 1B 280 53.76
4.65 11.65 60.34 0.97 8.80 8.06 2 1B 280 49.42 2.97 9.48 56.99 0.46
7.38 8.25 3 1B 280 51.26 2.33 8.25 55.63 0.87 4.99 5.65 4
Opalescence 840 52.78 1.75 6.14 57.26 1.42 2.10 6.04 5 Opalescence
840 56.35 1.79 5.21 59.13 0.65 2.44 4.09 6 Opalescence 840 55.71
2.72 7.10 58.60 1.09 4.75 4.07
[0040] The average .DELTA.E for the Example 1B group was 7.32,
whereas the average .DELTA.E for the Opalescence group was 4.73.
The present inventive compositions are thus shown to offer a
substantially improved degree of tooth bleaching in a shorter
exposure time than a prior art composition.
* * * * *