Delivery system for a tooth whitener using a strip of material having low flexural stiffness

A system for delivering a tooth whitening substance to a plurality of adjacent teeth, the delivery system comprising a strip of flexible material having a sufficient flexibility to form a curved shape on a plurality of adjacent teeth and a tooth whitening substance. The strip of material is readily conformable to the teeth surfaces and to interstitial tooth spaces without permanent deformation when the delivery system is placed thereagainst. The tooth whitening substance is applied to the strip of material such that when the delivery system is placed on the surface of the teeth, the substance contacts the surface providing an active onto the surface. The substance also provides adhesive attachment between the strip of material and the surface to hold the delivery system in place for a sufficient amount of time to allow the active to act upon the surface. The method of delivery includes pre-coating the strip of material or having the wearer apply substance to the strip of material and then applying the delivery system to the teeth surfaces.

FIELD OF THE INVENTION 
The present invention relates to a system for the delivery of a tooth 
whitening substance to a plurality of adjacent teeth and more particularly 
to such delivery system wherein the substance is protected from erosion 
and interaction with saliva within the mouth for a time sufficient to 
enable an active provided by the substance to cause tooth whitening. The 
delivery system comprises a strip of material and tooth whitening 
substance. Even more particularly, the present invention relates to 
disposable delivery systems that are inexpensive and unobtrusive. The 
present invention also relates to a method of delivering a tooth whitening 
substance to a plurality of adjacent teeth. 
BACKGROUND OF THE INVENTION 
The most common implement for dental hygiene is the toothbrush. The 
mechanical action of the toothbrush bristles aids in the removal of food 
particles, plaque, and the like. The toothbrush is normally used with a 
toothpaste. Prior to about 1955, a typical toothpaste consisted of a 
surfactant and an abrasive material. These products were simply intended 
to augment the mechanical action of the brushing. 
In 1955, CREST.RTM. toothpaste with fluoride, a Trademark of The Procter & 
Gamble Company of Cincinnati, Ohio, was introduced and the toothbrush and 
fluoride toothpaste combination proved to be a suitable means to deliver a 
fluoride treatment to the teeth surfaces. Subsequently, other active 
ingredients, such as tartar control agents, have been added to toothpaste 
to provide further dental hygiene benefits. Consumers have also turned 
their attention to the cosmetic aspects of dental care, such as teeth 
straightening and whitening. 
Given the success of delivering chemicals which provide therapeutic 
benefits for oral care, it is reasonable to expect similar success in 
accomplishing the cosmetic benefit via routine brushing. However, people 
who are serious about whitening their teeth and who have been disappointed 
by the results of whitening dentifrices, often resort to professional help 
for whitening their teeth. 
Professional teeth whitening programs provided by dentists generally fall 
into two categories: an in-office bleaching procedure and an 
outside-the-office bleaching procedure. The in-office procedure involves 
several visits, each of which begins with the fabrication of a specially 
fitted rubber dam within the mouth to prevent the bleaching chemicals, 
typically hydrogen peroxide, from contacting the soft oral tissue. The 
strength of the peroxide bleach mandates the use of the dam. 
The outside-the-office bleaching program differs in that the patient 
applies the bleaching agent to his or her own teeth using a lower strength 
chemical over an extended period of time, typically several hours a day 
for several weeks. The outside-the-office program typically requires an 
initial fitting in the dentist's office for an appliance which is specific 
to the particular patient. The appliance is a device that is fabricated to 
fit precisely onto the patient's teeth and is used to deliver to the 
patient's teeth a bleaching gel. The patient is responsible for measuring 
and applying the bleaching agent to the surfaces of the teeth using the 
appliance as the means for delivery and containment. 
Because the appliance is reused, it must be sufficiently robust to endure 
repeat handling, cleaning, filling, installation, and wearing. Such 
appliances are relatively rigid in order to maintain fit during repeat 
use. Typically, a patient uses the device in time periods when social 
contact can be avoided. 
There are now non-professional programs available to persons interested in 
whitening their teeth using commercial products available at drug stores. 
The commercial products provide a kit which includes a generic appliance 
and a container of bleaching gel. The obvious appeal is the lower cost of 
the program. A major disadvantage of this "one size fits all" appliance is 
the greater void between the interior walls of the appliance and the teeth 
versus the professionally fitted appliance. Hence, in order to insure 
intimate contact of the bleaching gel and the teeth surfaces, more 
bleaching gel is required. Furthermore, the poorer fit means a greater 
loss of bleaching gel onto the gums, into the oral cavity, and eventual 
ingestion. The commercial kits, like the outside-the-office professionally 
administered program, require the user to clean and to reuse the 
appliance. Since generic appliances are not fitted to the individual user, 
they are even more bulky in the mouth than the fitted appliances and thus 
they restrict social discourse to a greater degree. 
One attempt to remedy some of the problems of the commercial kits is 
disclosed in U.S. Pat. No. 5,575,654, issued to Fontenot on Nov. 19, 1996. 
Fontenot discloses a prepackaged moldable dental appliance, adapted to fit 
a wide range of variously sized dental arches, which contains a 
premeasured amount of medicinal or bleaching agent. In use, the dental 
appliance is removed from the packaging, aligned in a parallel fashion to 
the edges of the teeth and pushed over the teeth in the direction of the 
periodontal tissue until it covers the teeth surfaces. 
Another solution is disclosed in U.S. Pat. No. 5,310,563, issued to Curtis 
et al. on May 10, 1994. Curtis et al. disclose a putty-like material which 
is formed by pressing against the teeth. It is held in place by mechanical 
engagement with undercut surfaces and by friction. The composition 
encapsulates the active. 
Other methods are disclosed in U.S. Pat. No. 5,425,953, issued to Sintov et 
al. on Jun. 20, 1995. Sintov et al. discloses a liquid polymer composition 
for bleaching of the teeth. The liquid polymer composition forms a film 
after applied to the teeth. Other references which disclose using a film 
in the oral cavity include U.S. Pat. No. 4,713,243 issued to Schiraldi et 
al. on Dec. 15, 1987, and U.S. Pat. No. 2,835,628, issued to Saffir on May 
20, 1958. 
What is needed is a low cost commercial delivery system, which has a 
customized fit for a minimal volume of a tooth whitening substance, and 
which is in conformable contact with the appropriate tooth surfaces and 
interstitial tooth spaces for rapid delivery of an active in such 
substance. In addition a delivery system is needed which does not require 
extensive user placement manipulation to be certain of good contact. 
Furthermore, what is needed is a non-bulky active containment means that 
will permit the wearer to use the system during social discourse without 
interfering with the wearer's speech or appearance. Also needed is a 
containment means that will protect the tooth whitening substance from 
erosion from contact with inner mouth surfaces and saliva. 
SUMMARY OF THE INVENTION 
In practicing the present invention, a strip of material is applied by the 
wearer to a plurality of adjacent teeth. The side of the strip of material 
facing the tooth is coated with a tooth whitening substance. The substance 
is preferably in a viscous state, such as a gel, so that it provides not 
only the active but also tackiness between the teeth surfaces and the 
strip of material to hold the strip of material in place. The conformable 
strip of material is preferably of a size that individually fits the front 
6-8 teeth of the upper or lower rows of teeth when positioned against the 
teeth. As a soft, conformable material, the strip may come into contact 
with the wearer's gums without causing physical irritation. The strip of 
material readily conforms to the teeth by lightly pressing it thereagainst 
and/or by the wearer gently sucking through the gaps between teeth. The 
strip of material is readily conformable without permanent deformation to 
the shape of the teeth when the delivery system is placed thereagainst. 
The strip of material is easily removed by the wearer after use by peeling 
it off. Preferably, each successive treatment uses a fresh strip of 
material. 
By being a relatively thin coating, the tooth whitening substance is low in 
volume compared to the substance contained by rigid trays fitted or 
unfitted. Therefore, substance is not wasted, and little of it is 
accidentally ingested or otherwise available for irritation of oral cavity 
surfaces for which it is not intended. Preferably, the strip of material 
and substance are substantially transparent so as to be almost 
unnoticeable when worn. 
The delivery system also includes the tooth whitening substance applied to 
the strip of material. When the delivery system is placed on the surface 
of the teeth, the substance contacts the surface providing an active onto 
the surface. The substance also provides adhesive attachment between the 
strip of material and the surface to hold the delivery system in place for 
a sufficient time to allow the active to act upon the surface. Preferably, 
the substance is in the form of a gel, which is a substantially uniform 
continuous coating on the strip of material. 
In another aspect of the present invention, a method of delivering a tooth 
whitening substance to the surface of the teeth includes the step of 
applying the substance onto a conformable strip of material. This is 
followed by applying the conformable strip of material to the surface of 
the teeth without permanent deformation of the strip of material. The 
substance provides an active onto the surfaces and also provides adhesive 
attachment between the strip of material and the surface to hold the 
delivery system in place for a sufficient time to allow the active to act 
upon the surface.

DETAILED DESCRIPTION OF THE INVENTION 
The abbreviation "cm", as used herein, means centimeter. The abbreviation 
"mm", as used herein, means millimeter. 
Referring now to the drawings, and more particularly to FIGS. 1 and 2, 
there is shown a first preferred embodiment of the present invention, 
which is generally indicated as 10. Embodiment 10 represents a delivery 
system for a tooth whitening substance. Delivery system 10 has a strip of 
material 12, which is initially substantially flat, preferably with 
rounded corners. 
Applied or coated onto strip of material 12 is a tooth whitening substance 
14. Preferably, substance 14 is homogeneous, uniformly and continuously 
coated onto strip of material 12, as shown in FIG. 3. However, substance 
14 may alternatively be a laminate or separated layers of components, an 
amorphous mixture of components, separate stripes or spots or other 
patterns of different components, or a combination of these structures 
including a continuous coating of oral care substance 14 along a 
longitudinal axis of a portion of strip of material 12. 
As shown in FIG. 4, an alternative embodiment, a strip of material 12 may 
have shallow pockets 18 formed therein. When substance 14 is coated on a 
substance-coated side of strip of material 12, additional substance 14 
fills shallow pockets 18 to provide reservoirs of additional substance 14. 
FIGS. 5 and 6 show a delivery system 24 of the present invention applied to 
a plurality of adjacent teeth and the surface of a tooth. Embedded in 
adjacent soft tissue 20 is a plurality of adjacent teeth 22. Adjacent soft 
tissue is herein defined as soft tissue surfaces surrounding the tooth 
structure including: papilla, marginal gingiva, gingival sulculus, inter 
dental gingiva, gingival gum structure on lingual and buccal surfaces up 
to and including muco-ginival junction and the pallet. 
In both FIGS. 5 and 6, delivery system 24 represents strip of material 12 
and substance 14, with substance 14 on the side of strip of material 12 
facing adjacent teeth 22. Substance 14 may be pre-applied to strip of 
material 12 or applied to strip of material 12 by the delivery system 
user. In either case, strip of material 12 has a thickness and flexural 
stiffness which enable it to conform to the contoured surfaces of adjacent 
teeth 22 and to adjacent soft tissue 20. The strip of flexible material 
has sufficient flexibility to form a curved shape around a plurality of 
adjacent teeth. The strip of material is also readily conformable to tooth 
surfaces and to the interstitial tooth spaces without permanent 
deformation when the delivery system is applied. The delivery system is 
applied without significant pressure. 
FIGS. 7 and 8 show delivery system 24 of the present invention applied to 
both front and rear surfaces of a plurality of adjacent teeth 22 as well 
as to adjacent soft tissue 20 located by the front surfaces of the teeth. 
Delivery system 24 represents strip of material 12 and substance 14, with 
substance 14 on the side of strip of material 12 facing adjacent teeth 22. 
FIGS. 9 and 10 shows a optional release liner 27. Release liner 27 is 
attached to strip of material 12 by substance 14. Substance 14 is on the 
side of strip of material 12 facing release liner 27. This side is applied 
to the tooth surface once release liner 27 is removed. 
Strip of Material 
The strip of material serves as a protective barrier to substantially 
prevent saliva contacting the tooth whitening substance and leaching 
and/or erosion of the tooth whitening substance from the surface of the 
teeth by the wearer's lips, tongue, and other soft tissue. In order for an 
active in tooth whitening substance to act upon the surface of tooth over 
an extended period of time, from several minutes to several hours, it is 
important to minimize such leaching and/or erosion. The term "act upon" is 
herein defined as bringing about a desired change. For example, if the 
substance is a tooth whitener, it bleaches color bodies to bring about 
whitening. 
The strip of material may comprise materials such as polymers, natural and 
synthetic wovens, non-wovens, foil, paper, rubber, and combinations 
thereof. The strip of material may be a single layer of material or a 
laminate of more than one layer. Generally, the strip of material is 
substantially water impermeable. The material may be any type of polymer 
that meets the required flexural rigidity and is compatible with tooth 
whitening actives, such as peroxide. The material may comprise a single 
polymer or a mixtures of polymers. Suitable polymers include, but are not 
limited to, polyethylene, ethylvinylacetate, ethylvinyl alcohol, 
polyesters such as Mylar.RTM. manufactured by DuPont, fluoroplastics such 
as Teflon.RTM. manufactured by DuPont, and combinations thereof 
Preferably, the material is polyethylene. The strip of material is 
generally less than about 1 mm thick, preferably less than about 0.05 mm 
thick, and more preferably from about 0.001 to about 0.03 mm thick. A 
polyethylene strip of material is preferably less than about 0.1 mm thick 
and more preferably from about 0.005 to about 0.02 mm thick. 
Preferably, the shape of the strip of material is any shape that has 
rounded corners. "Rounded corners" is defined as not having any sharp 
angles or points. The conformable strip of material is preferably of a 
size that individually fits the row of teeth desired to be bleached. 
Generally, this is the front 6-8 teeth of the upper or lower rows of teeth 
that are visible when the wearer is smiling. Optionally, the strip of 
material may fit the entire upper or lower rows of teeth when positioned 
against the teeth. The size of the strip of material depends upon many 
factors, including the number of teeth to be bleached, the size of the 
teeth, and personal preference of the wearer. In general, the length of 
the strip of material is from about 2 cm to about 12 cm and preferably 
from about 4 cm to about 9 cm. The width of the strip of material will 
also depend upon many factors, including whether or not the strip of 
material wraps around the teeth and covers both surfaces of the tooth. In 
a general application, the width of the strip of material is from about 
0.5 cm to about 4 cm and preferably from about 1 to about 2 cm. 
The strip of material may contain shallow pockets. When the substance is 
coated on a substance-coated side of strip of material, additional 
substance fills shallow pockets to provide reservoirs of additional 
substance. Additionally, the shallow pockets help to provide a texture to 
the delivery system. The film will preferably have an array of shallow 
pockets. Generally, the shallow pockets are approximately 0.4 mm across 
and 0.1 mm deep. When shallow pockets are included in the strip of 
material and substances are applied to it in various thicknesses, the 
overall thickness of the delivery system is generally less than about 1 
mm. 
Preferably, the overall thickness is less than about 0.5 mm. 
Flexural stiffness is a material property that is a function of a 
combination of strip thickness, width, and material modulus of elasticity. 
This test is a method for measuring the rigidity of polyolefin film and 
sheeting. It determines the resistance to flexure of a sample by using a 
strain gauge affixed to the end of a horizontal beam. The opposite end of 
the beam presses across a strip of the sample to force a portion of the 
strip into a vertical groove in a horizontal platform upon which the 
sample rests. A microammeter, wired to the strain gauge is calibrated in 
grams of deflection force. The rigidity of the sample is read directly 
from the microammeter and expressed as grams per centimeter of sample 
strip width. In the present invention, the strip of material has a 
flexural stiffness of less than about 5 grams/cm as measured on a 
Handle-O-Meter, model #211-300, available from Thwing-Albert Instrument 
Co. of Philadelphia, Pa., as per test method ASTM D2923-95. Preferably, 
the strip of material has a flexural stiffness less than about 4 grams/cm, 
more preferably less than about 3 grams/cm, and most preferably from about 
0.1 grams/cm to about 1 grams/cm. Preferably, the flexural stiffness of 
the strip of material is substantially constant and does not significantly 
change during normal use. For example, the strip of material does not need 
to be hydrated for the strip to achieve the low flexural stiffness in the 
above-specified ranges. 
This relatively low stiffness enables the strip of material to drape over 
the contoured surfaces of teeth with very little force being exerted; that 
is, conformity to the curvature of the wearer's mouth and gaps between 
adjacent teeth is maintained because there is little residual force within 
strip of material to cause it to return to its substantially flat shape. 
The flexibility of the strip enables the strip of material to contact 
adjoining soft tissue over an extended period of time without physical 
irritation. The strip of material does not require pressure forming it 
against the teeth. 
The strip of material is held in place on a plurality of adjacent teeth by 
adhesive attachment provided by the substance. The viscosity and general 
tackiness of the substance cause the strip of material to be adhesively 
attached to a plurality of adjacent teeth without substantial slippage 
under the potential friction from the lips, tongue, and other soft tissue 
rubbing against the strip of material during mouth movements associated 
with talking, drinking, etc. However, this adhesion to the teeth is low 
enough to allow the delivery system to be easily removed by the wearer by 
peeling off the strip of material using one's finger or fingernail. The 
delivery system is easily removable from the surfaces of the teeth without 
the use of an instrument, a chemical solvent, or undue friction. Chemical 
solvents include any organic solvents commonly used in oral care products 
such as alcohol and other safe solvents such as water, which could be used 
to dilute the gelling agent. Undue friction is described as any type of 
rubbing with one's finger or a soft implement, such as cotton balls, 
swabs, or gauze pads. 
A peel force of from about 1 gram to about 50 grams for a 1.5 cm strip 
width (approximately 17 grams/cm) is all that is required. Preferably, the 
peel force is from about 5 grams to about 40 grams and more preferably 
from about 10 grams to about 30 grams. The low peel force is desired for 
consumer handling purposes. The low peel force is possible because of the 
non-aggressive nature of a gel substance. Only when the flexural stiffness 
of the strip is low can the adhesion of the substance also be low. The 
adhesion of a stiffer strip would have to be greater in proportion to the 
strip stiffness in order to prevent the strip from returning to its flat 
condition and pulling away from the contoured surface of a plurality of 
teeth. 
The strip of material may be formed by several of the film making processes 
known in the art. Preferably, a strip of material made of polyethylene is 
made by a blown process or a cast process. Processes, such as extrusion 
and other processes that do not affect the flexural rigidity of the strip 
of material, are also feasible. Additionally, the substance may be 
incorporated onto the strip during the processing of the strip. The 
substance may be a laminate on the strip. 
Tooth Whitening Substance 
The tooth whitening substance is a composition, compound, or mixture 
capable of influencing or effecting a desired change in appearance and/or 
structure of the surface it contacts. Examples of appearance and 
structural changes include, but are not necessarily limited to, whitening, 
stain bleaching, stain removal, plaque removal, and tartar removal. 
Preferably, the active is for the whitening of the tooth surfaces. 
The amount of substance applied to the strip of material or teeth will 
depend upon the size and capacity of the piece of material, concentration 
of the active, and the desired benefit. Generally, less than about 1 gram 
of substance is required. Preferably, from about 0.05 grams to about 0.5 
grams and more preferably from about 0.1 gram to about 0.4 grams of the 
substance is used. The amount of substance per square cm of material is 
less than about 0.2 grams/cm.sup.2, preferably from about 0.005 to about 
0.1 grams/cm.sup.2, and more preferably from about 0.01 grams/cm.sup.2 to 
about 0.04 grams/cm.sup.2. 
The substance of the present invention can be in the form of a viscous 
liquid, paste, gel, solution, or other suitable form that can provide 
sufficient adhesion. Preferably, the substance is in the form of a gel. 
The substance will have a viscosity of from about 200 to about 1,000,000 
at low shear rates (less than one 1/seconds). Preferably, the viscosity is 
from about 100,000 to about 800,000 cps and more preferably from about 
400,000 to about 600,000 cps. 
Actives suitable for whitening include any material safe for use in the 
oral cavity which provides bleaching or stain removal. The actives 
suitable for whitening are selected from the group consisting of the 
peroxides, metal chlorites, perborates, percarbonates, peroxyacids, and 
combinations thereof. Suitable peroxide compounds include hydrogen 
peroxide, calcium peroxide, carbamide peroxide, and mixtures thereof. Most 
preferred is carbamide peroxide. Suitable metal chlorites include calcium 
chlorite, barium chlorite, magnesium chlorite, lithium chlorite, sodium 
chlorite, and potassium chlorite. Additional whitening actives may be 
hypochlorite and chlorine dioxide. The preferred chlorite is sodium 
chlorite. 
The tooth whitening active is present in an amount of from about 0.01% to 
about 40%, by weight of the substance. If a peroxide compound is chosen as 
the active, the peroxide compound should provide an amount of hydrogen 
peroxide equivalent of from about 0.1% to about 20%, preferably from about 
0.5% to about 10%, and most preferably from about 1% to about 7%, by 
weight of the substance. To deliver this amount of hydrogen peroxide 
equivalent, the peroxide compound, such as carbamide peroxide, is 
generally present in an amount of from about 0.1% to about 30% and 
preferably from about 3% to about 20%, by weight of the substance. 
The actives are generally contained in an aqueous gel. The gel is a high 
viscosity matrix formed from gelling agents known in the art. These 
gelling agents are safe for oral use, do not readily dissolve in saliva, 
and do not react with or inactivate the oral care compounds incorporated 
into them. Generally, the gelling agent is a swellable polymer. 
Furthermore, the gel formed with these agents provides sufficient adhesive 
attachment of the film material to the targeted area of the mouth. The 
level of gelling agent to form the gel composition is from about 0.1% to 
about 15%, preferably from about 1% to about 10%, more preferably from 
about 2% to about 8%, and most preferably from about 4% to about 7%, by 
weight of the substance. 
Suitable gelling agents useful in the present invention include 
carboxypolymethylene, carboxymethyl cellulose, carboxypropyl cellulose, 
poloxamer, carrageenan, Veegum, carboxyvinyl polymers, and natural gums 
such as gum karaya, xanthan gum, Guar gum, gum arabic, gum tragacanth, and 
mixtures thereof. The preferable gelling agent for use in the present 
invention is carboxypolymethylene, obtained from B. F. Goodrich Company 
under the tradename "Carbopol". Particularly preferable Carbopols include 
Carbopol 934, 940, 941, 956 and mixtures thereof. Particularly preferred 
is Carbopol 956. Carboxypolymethylene is a slightly acidic vinyl polymer 
with active carboxyl groups. The normal concentration of various 
carboxypolymethylene resins in water, according to the manufacturer, is 
below about 2%. However, it has been found that by preparing 
supersaturated carboxypolymethylene compositions having an absolute 
concentration in the ranges specified above, suitable high viscosity oral 
gel compositions may be prepared. 
The concentrated carboxypolymethylene gels have a number of important 
characteristics in addition to high viscosity. Enough carboxypolymethylene 
is added to the oral gel compositions beyond that required to provide high 
viscosity such that a significant quantity of saliva or water is required 
to lower the viscosity to the point that the composition may be diluted 
and washed out by saliva. The concentrated carboxypolymethylene 
composition also has a unique tackiness or stickiness which retains and 
seals the strip material against the targeted oral cavity surface it is 
affixed to, particularly teeth. However, care should be taken to avoid too 
much carboxypolymethylene thereby making insertion or withdrawal of the 
strip material difficult. 
Water is also present in the gel compositions disclosed herein. The water, 
employed in the present invention should, preferably, be deionized and 
free of organic impurities. Water comprises from about 0.1% to 95%, 
preferably from about 5% to about 90%, and most preferably from about 10% 
to about 80%, by weight of the substance. This amount of water includes 
the free water that is added plus that amount that is introduced with 
other materials. 
A pH adjusting agent may also be added to optimize the storage stability of 
the gel and to make the substance safe for oral tissues. These pH 
adjusting agents, or buffers, can be any material which is suitable to 
adjust the pH of the substance. Suitable materials include sodium 
bicarbonate, sodium phosphate, sodium hydroxide, ammonium hydroxide, 
sodium stannate, triethanolamine, citric acid, hydrochloric acid, sodium 
citrate, and combinations thereof. The pH adjusting agents are added in 
sufficient amounts so as to adjust the pH of the gel composition to about 
4.5 to about 11, preferably from about 5 to about 8.5, and more preferably 
from about 5.5 to about 7. pH adjusting agents are generally present in an 
amount of from about 0.01% to about 15% and preferably from about 0.05% to 
about 5%, by weight of the substance. 
While the gel described above provides sufficient adhesiveness, additional 
gelling agents may also be included in the formula to help the active 
ingredients adhere to the tissues of the oral cavity. Suitable agents 
include both polymers with limited water solubility as well as polymers 
lacking water solubility. These polymers deposit a thin film on both the 
oral cavity's soft and hard tissues when saliva combines with the instant 
composition. Suitable limited water solubility adhesives include: hydroxy 
ethyl or propyl cellulose. Adhesives lacking water solubility include: 
ethyl cellulose and polyox resins. Another possible adhesive suitable for 
use in the instant composition is polyvinylpyrrolidone with a molecular 
weight of about 50,000 to about 300,000. Still another possible adhesive 
suitable for use in the instant composition is a combination of Gantrez 
and the semisynthetic, water-soluble polymer carboxymethyl cellulose. 
An additional carrier material may also be added to the substance. Carrier 
materials can be humectants. Suitable humectants include glycerin, 
sorbitol, polyethylene glycol, propylene glycol, and other edible 
polyhydric alcohols. Humectants are generally present in an amount of from 
about 10% to about 95%, preferably from about 20% to about 80%, and more 
preferably from about 50% to about 70%, by weight of the substance. In 
addition to the above materials of the gel of the present invention, a 
number of other components can also be added to the substance. Additional 
components include, but are not limited to, flavoring agents, sweetening 
agents, xylitol, opacifiers, coloring agents, and chelants such as 
ethylenediaminetetraacetic acid. These additional ingredients can also be 
used in place of the compounds disclosed above. 
Release Liner 
The release liner may be formed from any material which exhibits less 
affinity for substance than substance exhibits for itself and for the 
strip of material. The release liner preferably comprises a rigid sheet of 
material such as polyethylene, paper, polyester, or other material which 
is then coated with a non-stick type material. The release liner material 
may be coated with wax, silicone, polyester such as Teflon.RTM., 
fluoropolymers, or other non-stick type materials. A preferred release 
liner is Scotchpak.RTM., produced by 3M. The release liner may be cut to 
substantially the same size and shape as the strip of material or the 
release liner may be cut larger than the strip of material to provide a 
readily accessible means for separating the material from the strip. The 
release liner may be formed from a brittle material which cracks when the 
strip is flexed or from multiple pieces of material or a scored piece of 
material. Alternatively, the release liner may be in two overlapping 
pieces such as a typical adhesive strip bandage type design. A further 
description of materials suitable as release agents is found in 
Kirk-Othmer Encyclopedia of Chemical Technology, Fourth Edition, Volume 
21, pp. 207-218, incorporated herein by reference. 
EXAMPLES 
The strip of material is preferably a 0.013 mm thick piece of polyethylene 
film. The film preferably has an array of shallow pockets, typically 0.4 
mm across and 0.1 mm deep. The strip of material has a flexural stiffness 
of about 0.6 grams/cm as measured on a Handle-O-Meter, model #211-300, 
available from Thwing-Albert Instrument Co. of Philadelphia, Pa., as per 
test method ASTM D2923-95. 
An example of a tooth whitener is a gel described as follows: Combine 70% 
glycerin, 5% carboxypolymethylene, 10% carbamide peroxide, and 15% water 
adjusted to pH 6.5 with sodium hydroxide. Mix until homogeneous. 
Additional examples of alternative tooth whitening gel are described as 
follows: Combine 8% carboxypolymethylene in approximately 84% water, add 
4% sodium hydroxide and enough sodium bicarbonate to bring the pH to about 
10. Dissolve in 3.75% sodium chlorite and mix until homogeneous. 
Combine 56% glycerin, 6% carboxypolymethylene, 10% carbamide peroxide, and 
24% water. Add 4% sodium hydroxide (50% solution) to adjust the pH. Mix 
until homogeneous. 
Combine 68% glycerin, 6% carboxypolymethylene, 22% carbamide peroxide, and 
4% sodium hydroxide (50% solution). Mix until homogeneous. 
Combine 25% glycerin, 69.7% water, 2% xanthan gum, 3% 
carboxymethylcellulose, and 0.3% carbamide peroxide. Mix until 
homogeneous. 
Combine 24% poloxamer, 20% glycerin, 46% polyethylene glycol, and 10% 
carbamide peroxide. Mix until homogeneous. 
Commercial tooth whiteners, such as Opalescence and Nu-Pro Gold, are also 
operable with the delivery system of the present invention. 
Method of Use 
In practicing the present invention, a strip of material is applied by the 
wearer to a plurality of adjacent teeth. The side of the material facing 
the teeth is coated with a tooth whitening substance which is preferably 
in a viscous state to provide not only the active but also tackiness 
between the tooth surfaces and the strip of material to hold the strip in 
place for an extended period of time. The strip of material readily 
conforms to the teeth by lightly pressing it against the teeth and/or by 
the wearer gently sucking through the gaps between the teeth. The strip of 
material is easily removed by the wearer by peeling it off. Preferably, 
each successive treatment will use a fresh strip of material. 
The tooth surface is not required to be prepared before the delivery system 
is applied. For example, the wearer may or may not choose to brush his 
teeth or rinse his mouth before applying the delivery system. The surfaces 
of the teeth are not required to be dried or to be excessively wet with 
saliva or water before the strip of material is applied. 
Preferably, the strip of material and substances are substantially 
transparent so as to be almost unnoticeable when worn. Thinness of the 
delivery system enables the higher temperature inside of the wearer's 
mouth to conduct heat through the strip of material to the normally cooler 
teeth in order to accelerate the rate of diffusion of the active material 
into the surfaces of the teeth. 
Preferably, the wearer applies the delivery system of the present to the 
teeth continuously for about 5 minutes to about 120 minutes a day, 
preferably from about 30 minutes to about 60 minutes. Generally, this is 
done once a day for about 7 to 28 days. The amount of time and the number 
of days are dependent upon several factors, including the amount of 
bleaching desired, the wearer's teeth, and if initial or maintenance 
bleaching is desired. The bleaching is done to achieve a whitening benefit 
of 1-4 shade guide improvement as measured by VITA LUMIN.RTM. Vacuum 
Farbskala Shade Guides, a product of VITA Zahnfabrik, of BadSackingen, 
Germany. 
When the wearer removes the strip of material from the tooth, there may be 
a residue of substance remaining on the surface. This residual will not be 
great, as the tooth whitening substance has affinity for both the film and 
for itself. If residual substance remains, it may be easily removed by 
brushing or rinsing. 
While particular embodiments of the present invention have been illustrated 
and described, it will be obvious to those skilled in the art that various 
changes and modifications may be made without departing from the spirit 
and scope of the invention, and it is intended to cover in the appended 
claims all such modifications that are within the scope of the invention.