Structure and compositions increasing the stability of peroxide actives

The first structure and composition for improving the stability of active peroxides. This application is part of the continuation application of the U.S. application 09/605774 filed on June 28, 2000 and the U.S. application 09/605220 filed on June 28, 2000 Part of the continuation application. The above-mentioned US application 09/605220 is again part of the continuation application of the US application 09/196364 filed on November 19, 1998. The above-mentioned US application 09/196364 is again the US application 08/ filed on June 6, 1997. 870664, part of the current U.S. Patent No. 5,894,017 continues to apply. This application is again a partial continuation application of US application 09/268171 filed on March 15, 1999, and the contents of these patent documents are fully incorporated herein by reference.

Technical Field of the Invention The present invention relates to structures and compositions for improving the stability of active peroxides, and in particular to structures and compositions used in tooth whitening systems containing active peroxides.

BACKGROUND In recent years, tooth whitening has become very popular. More and more consumers choose to whiten their teeth. The methods used to whiten teeth include the use of toothpaste, mouthwash, chewing gum, spot bleaching solution, and more commonly the use of common tooth whitening solutions purchased with a payment subpoena or obtained from a dentist. The tooth whitening solution contains active ingredients capable of bleaching teeth. This solution is put into a dental tray, and the patient wears the dental tray to bleach his or her teeth. Usually, the oral composition is contained in a plastic squeeze bottle, tube or syringe.

It is known that tooth whitening active materials are difficult to maintain activity for a long time. The most commonly used tooth bleaching agent is peroxide, which is known to be very reactive. In order to improve stability, peroxide can be filled into capsules to form a two-component compound, or stabilizers can be added to maintain the peroxide concentration. Generally, peroxide compositions are stored in sealed bulk containers, such as syringes or tubes.

The non-bulk tooth whitening system includes a band and a predetermined amount of the tooth whitening composition, which have been mentioned in U.S. Patent Nos. 5,984,017, 587969L 5891453, 6045811, and 5989569, the contents of which are fully incorporated herein by reference. These improved systems provide a one-time, user-friendly method of whitening teeth. However, peroxides containing oral compositions are more difficult to stabilize for a long period of time because such oral compositions are

01811973.5 It is stored in thin layers, not in syringes or in batches.

SUMMARY OF THE INVENTION A peroxide product is provided. This peroxide product includes a package with a headspace, a substrate placed in the package, and a thin layer of a composition with active peroxide and polyol, where the thin layer is adjacent to the substrate. The peroxide product also includes at least one means to increase the stability of the active peroxide in the composition. After being stored in the dark at about 25°C for 12 months after manufacture, the active peroxide concentration of the thin layer of the composition is at least about 43% of the initial concentration.

Brief Description of the Drawings Although the claims at the end specifically point out and clearly claim the rights of the present invention, it can be considered that the present invention can be better understood with reference to the following description of the drawings: Figure 1 is a better one made according to the present invention Perspective view of the teeth whitening system.

Fig. 2 is an end cross-sectional view of the tooth whitening system of Fig. 1 along line 2-2.

Figure 3 is an end cross-sectional view of the preferred tooth whitening system of Figure 1 in a package.

Figure 4 is a perspective view of another preferred tooth whitening system made in accordance with the present invention.

Figure 5 is an end cross-sectional view of the tooth whitening system of Figure 4 along line 5-5.

Figure 6 is a perspective view of the tooth whitening system of Figure 4 with the first part of the substrate removed.

Figure 7 is a perspective view of another preferred tooth whitening system made in accordance with the present invention.

Fig. 8 is an end cross-sectional view of the tooth whitening system of Fig. 7 along line 8-8.

Figure 9 is a top plan view of another preferred tooth whitening system made in accordance with the present invention.

Figure 10 is a top plan view of yet another preferred tooth whitening system made in accordance with the present invention.

Fig. 11 is a schematic diagram of a method of manufacturing the tooth whitening system of Fig. 1.

DETAILED DESCRIPTION OF THE INVENTION The present invention will now be described in detail according to some preferred embodiments. These embodiments are shown in the drawings. The same numbers in all the drawings represent the same parts, with the same last two digits (for example, 20 and 120). ) Or parts with the same letter suffix (such as 22A and 22B) refer to similar parts. For the sake of completeness in the discussion below, the present invention directly relates to means for improving the stability of active peroxides. The term "stable

01811973.5 "Qualitative" refers to the tendency of active peroxide (or other unstable active substance) to maintain its initial concentration for a fixed period of time (for example, 3 months, 6 months, 12 months, etc.), and the fixed period of time is from The time when the tooth whitening composition is manufactured to form a thin layer is calculated. Even if the stability of the active peroxide is improved to a small to moderate extent, it can have a significant impact on the shelf life of the peroxide system. For example, the composition The active peroxide with an initial concentration of 6% retains 28% of it after 12 months. If this number is increased to 39%, the storage life of the peroxide system of the latter will be extended by 3 months. The end of life means that the minimum effective concentration is 3%. A particularly preferred embodiment of the present invention is shown in Figure 1, which is a tooth whitening comprising a substrate 22, a thin layer of tooth whitening composition 24 and a carrier 26 System 20, the tooth whitening composition contains active peroxide. The substrate 22 is used to apply the tooth whitening composition to the teeth, and it serves as a protective barrier, mainly to prevent saliva from contacting the tooth whitening composition, It can also be used to prevent the tooth whitening composition from eroding the tooth surface through the users lips, tongue, and other soft tissues. The carrier 26 can also be used as a protective barrier, but the substrate 22 is applied before the tooth whitening composition is applied to the teeth. And the thin layer 24 is separated from the carrier 26, so that the thin layer 24 Exposed. The means to improve the stability of the tooth whitening composition can be the concentration of polyol, the ratio of the exposed surface area of the thin layer 24 to the volume of the thin layer 24, the ratio of the unexposed surface area of the thin layer 24 to the volume of the thin layer 24, and the formation of a substrate. 22 or the material of at least a part of the surface of the carrier 26 that is in contact with the composition, the ratio of the volume of the head space of the package to the volume of the thin layer 24, and a combination of the above factors. Although the present invention only describes the tooth whitening system 20 for the sake of simplicity, it should be considered that the present invention can be applied to other oral compositions containing active peroxides, such as tartar inhibiting compositions, mineral supplemental compositions, and antiseptic compositions. , Gingivitis composition, therapeutic function composition, etc. It is expected that the present invention is also suitable for use with other systems containing active peroxides (such as fabric bleaching systems, topical disinfection systems, etc.). Moreover, it is expected that the present invention can also be used with compositions containing other unstable or volatile active substances (such as alcohol, ethanol, menthol, menthol and other fragrances, methyl salicylate, etc.).

The tooth whitening composition contains an active peroxide, which is provided in the form of a thin layer 24 between the carrier 26 and the substrate 22. The term "thin layer" as used herein refers to the material form or location of the tooth whitening composition. The thin layer 24 of the tooth whitening composition is generally on the substrate 22 and the carrier 26 or in contact with both. The thin layer 24 of the tooth whitening composition can be stored, coated or spread on the carrier 26. The thin layer 24 of the tooth whitening composition preferably has a thickness of about 0.01 to about 3 mm, more preferably about 0.02 to about 2 mm, most preferably about 0.05 to about 1 mm, and particularly preferably about 0.07 to about 0.5 mm. These test results are measured from the surface 28 of the carrier 26

01811973.5 The result obtained through the thin layer 24 of the tooth whitening composition upwards. Although the thin layer of the tooth whitening composition is suitably a uniform and continuous layer, it can also be uneven, discontinuous and/or uneven in phase structure. For example, the thin layer 24 may be a laminate or separate layer of each component, an amorphous mixture of each component, separate ribbons or dots of different components or other graphic forms, or a combination of these structures.

The tooth whitening composition of the present invention can be in the form of a viscous liquid, paste, gel, solution, or any other state or phase that can form a thin layer. The tooth whitening composition is preferably in the form of a gel with a viscosity of about 200-1000000 cps at a low shear rate (about 1 second T), preferably about 100,000-800000 cps, most preferably about 150,000-700000 cps, especially preferred About 300000-700000c_Ps_o The amount of the tooth whitening composition in the tooth whitening system 20 varies with its use, the size of the substrate 22, the concentration of active peroxide, and the benefits required. Generally, less than about 1 gram of tooth whitening composition is required in a tooth whitening system. It is preferable to provide 0.05 g to 0.5 g, more preferably about 0.1 g to 0.4 g of the tooth whitening composition. The amount of the tooth whitening composition per square centimeter of the substrate 22 is less than about 0.2 g/cm2, preferably about 0.005-0.1 g/cm2, more preferably about 0.01-0.05 g/cm2.

It is known in the prior art that tooth whitening compositions also have a certain yield stress. Yield stress is the amount of force applied to the material before it starts to move. The yield stress must be high enough so that the tooth whitening composition can form a thin layer and can cope with the interference caused by manufacturing, processing and storage. The yield stress of the tooth whitening composition is about 2-3000 Pa, preferably about 20-2000 Pa, more preferably about 200-1500 Pa, most preferably about 400-1200 Pa.

Active peroxides suitable for use in the present invention include hydrogen peroxide, calcium peroxide, hydrogen peroxide glands, and mixtures thereof. The most preferred is hydrogen peroxide. Other active peroxides include compositions capable of forming hydrogen peroxide when mixed with water, such as percarbonate, specifically sodium percarbonate. Although the active peroxide can be in any concentration, its concentration is preferably about 0.01% to 40% by weight of the tooth whitening composition in the tooth whitening system. The active peroxide should be able to generate an equivalent concentration of hydrogen peroxide of about 0.1% by weight to 20% by weight of the tooth whitening composition, preferably about 0.5% by weight to 15% by weight, more preferably about 1% by weight -10% by weight, most preferably about 2%-10%. It should be understood that these concentrations represent hydrogen peroxide, and other peroxide molecules that release hydrogen peroxide (such as hydrogen peroxide glands, calcium peroxide, etc.) must be converted.

Additional components in the tooth whitening composition may include, but are not limited to, water, gelling agents, wetting agents, pH adjusters, stabilizers, desensitizers, accelerators, or bleach catalysts. In addition to the above substances, many other substances can also be added

01811973.5 Substances, including but not limited to flavoring agents, sweeteners (such as saccharin, xylitol), opaque agents, coloring agents and chelating agents (such as ethylenediaminetetraacetic acid). These additional components are also used in place of the above-mentioned compounds.

Suitable gelling agents should not react with the components of the oral care composition. Commonly used gelling agents are swellable polymers. The effective concentration of the gelling agent for forming a thin layer of the tooth whitening composition varies with the type of gelling agent. The viscosity and yield stress of the thin layer should enable the tooth whitening composition to form a thin layer on the carrier. The tooth whitening composition using these gelling agents can also provide sufficient adhesive properties for the thin layer of material to adhere to the target area in the mouth. For example, the gelling agent for forming a tooth whitening composition containing carboxypolymethylene has a concentration of about 0.1% by weight to 15% by weight of the tooth whitening composition, preferably about 1% by weight to 10% by weight, More preferably, it is about 2% to 8% by weight, most preferably about 3% to 6% by weight. The effective concentration of poloxamer gelling agent is about 10%-40% by weight of the tooth whitening composition, preferably about 20%-35% by weight, more preferably about 25%-30% by weight %.

Suitable gelling agents used in the present invention include "Pemulen" (manufactured by BF Goodrich Company), carboxypolymethylene, cetomethyl cellulose, cetopropyl cellulose, ethyl cellulose, poloxamer , Synthetic laponite, carrageenan, Veegum, vinyl polymers and natural gums (such as karaya gum, xanthan gum, guar gum, gum arabic, gum tragacanth and their mixtures). The preferred gelling agent used in the present invention is carboxypolymethylene, which is Carbopol from BF Goodrich Company. Particularly preferred Carbopols include Carbopol 934>940>941, 956>971, 974>980 and mixtures thereof. Especially preferred is Carbopol 956. Acetyl polymethylene is a slightly acidic vinyl polymer with reactive acyl groups.

Other suitable gelling agents include polymers with limited water solubility, and polymers that are insoluble in water. Suitable binders with limited water solubility include: hydroxy ethyl or propyl cellulose. Binders that do not dissolve in water include ethyl cellulose and polyox resins. Other binders that may be suitable for use in the compositions of the present invention are polyvinylpyrrolidone with a molecular weight of about 50,000 to 300,000. Another possible suitable binder is a combination of Gantrez and the semi-synthetic water-soluble polymer carboxymethyl cellulose.

A pH adjusting agent can also be added to make the composition safe for oral soft tissues. These pH adjusters or buffers may be any substances as long as they can adjust the pH of the composition. Suitable materials include sodium bicarbonate, sodium phosphate, sodium hydroxide, money hydroxide, potassium hydroxide, sodium stannate, triethanolamine, citric acid, hydrochloric acid, sodium citrate, and mixtures thereof. To add a sufficient concentration of pH adjusting agent, the pH of the adjusted composition is about 3-10, preferably about 4-&5, and more preferably about 4.5-8. The concentration of pH adjuster is usually

01811973.5 The first is about 0.01% by weight to 15% by weight of the composition, preferably about 0.05% by weight to about 5% by weight.

Suitable stabilizers include benzoic acid, salicylic acid, butylated hydroxytoluene, tin salts, phosphates and the like. Suitable bleach catalysts include trichloroisooxyuric acid and phosphates such as tetrasodium pyrophosphate.

Desensitizers can also be used in tooth whitening compositions. These desensitizers are preferred for people with sensitive teeth. Desensitizers include potassium nitrate, citric acid, citrate, total chloride and their mixtures. Potassium nitrate is the preferred desensitizer. Other additives that can reduce tooth sensitivity can also be included in the tooth whitening composition of the present invention. Generally, the concentration of the desensitizer is about 0.01% to 10% by weight of the tooth whitening composition, preferably about 0.1% to 8% by weight, more preferably about 1% to 7% by weight.

The substrate 22 may be formed using materials including polymers, natural and synthetic fabrics, non-woven fabrics, metal flakes, paper, rubber, and combinations thereof. The substrate 22 (and the carrier 26) may be a single layer of material or a laminate of more than one layer. Suitable polymers include, but are not limited to, ethyl vinyl acetate, ethyl vinyl alcohol, polyesters (such as MYLAR® manufactured by DuPont), and mixtures thereof.

The carrier can be formed using any material, as long as its affinity for the tooth whitening composition is less than the affinity of the tooth whitening composition itself and its affinity for the substrate 22. For example, the carrier 26 can be formed of paper or polyester (such as SCOTCHPAK® produced by 3M Corp. of Minneapolis, MN), and it is coated with a non-adhesive material so that when the substrate 22 is peeled from the carrier 26, the teeth will increase. The white composition is separated from the carrier 26. The representative coating material may include wax, silicone, fluoropolymer (such as Teflon®, fluorosilicone), or other non-sticky types of materials. Moreover, suitable coatings may include those mentioned in U.S. Patent Nos. 3,810,874, 4,472,480, 4,567,073, 4,614,667, 4,830,910, and 5,306,758, the contents of which are fully incorporated herein by reference. For further description of materials suitable for this release agent, please refer to Kirk-Othmer Encyclopedia of Chemical Techmical Technology, Fourth Edition, Volume 21, pp207-218, which is incorporated herein by reference.

Although the tooth whitening system 20 mentioned here includes both the substrate 22 and the carrier 26, the tooth whitening system 20 (or other peroxide systems within the scope of the present invention) may only include the substrate 22 and the thin layer. twenty four. For example, the inside of the packaging for storing the substrate 22 and the thin layer 24 can be coated using the method similar to that described above for the carrier 26, so that the substrate 22 and the thin layer can be easily removed from the packaging during use. In addition, the form of the tooth whitening system 20 may be a roll shape instead of the flat shape shown here, and may include many sheet substrates and/or carriers. In addition, the substrate 22 and/or the carrier 26 may be other non-planar shapes, such as pre-formed braces or soft braces. The substrate and/or carrier can also use permanently deformable tape, wax or other suitable

01811973.5 It is a material composition that serves as a barrier to the tooth whitening composition and applies the whitening composition to the teeth.

Although the aforementioned materials for the substrate 22 and the carrier 26 are suitable for use in the present invention, the carrier 26 and/or the substrate 22 (or at least its surface 28 and/or 30 in contact with the active peroxide) is made of polyalkenyl It is preferably formed of polyethylene or polypropylene to improve the stability of the active peroxide in the thin layer 24 of the tooth whitening composition. Although these materials are preferred, it is believed that polyalkenyl mixtures, polyethylene mixtures, polypropylene mixtures, and combinations thereof are also suitable for use as the substrate 22 and/or carrier 26 of the present invention. As mentioned above, the carrier 26 may also be coated to help the tooth whitening composition detach from the carrier during manufacture and/or use. However, the paint used for it usually does not act as a barrier between the active peroxide and the underlying materials, so it is still necessary to appropriately select the following materials. But for reactive peroxides, any coating should be inert.

It has also been found that the stability of peroxides can be adversely affected by the presence of polyesters, especially polyols. Therefore, at least the surfaces 28 and 30 of the portion of the substrate 22 and/or the carrier 26 that are in contact with the tooth whitening composition are preferably formed of a material other than polyester, so that the polyester-containing material does not come into contact with the tooth whitening composition. The base material 22 and/or the carrier 26 are more preferably completely formed of materials other than polyester. Although it has been found that polyester and reactive peroxide have an undesirable interaction in the absence of polyols, the combination of all three components leads to a more negative interaction for the stability of the reactive peroxide.

The thickness of the substrate 22 and/or the carrier 26 is generally less than about 1 mm, preferably less than 0.05 mm, more preferably about 0.001 to 0.03 mm, most preferably less than about 0.1 mm, and particularly preferably about 0.005 to 0.02 mm. The thickness and permeability of the substrate 22 and/or carrier 26 can affect the stability of the tooth whitening composition. Generally, thicker straps provide a more stable tooth whitening composition. However, the thickness of the substrate must take into account the consumer's acceptance of comfort when using the belt.

Although the size of the substrate 22 can be determined according to the purpose of the tooth whitening system, the size of the substrate can also be individually determined to suit the teeth or tooth rows that need to be bleached. Generally, the teeth that need to be bleached are the 6-8 teeth on the front of the upper or lower row that are visible when the user smiles, or the upper or lower dentition. The substrate 22 can fit the entire upper or lower row of teeth when it is resting on the teeth. Most preferably, the size of the base material 22 should be such that it overlaps a gingival margin and can cover at least six front teeth (canine teeth versus canine teeth) located in the center. The base material 22 may be an upper jaw tape, which is a rectangle with rounded corners, and the size is approximately 6.5 cm long X 1.5 cm wide; it may also be a lower jaw tape, which is a trapezoid with rounded corners, and its size is approximately 5.0 Cm long X2.0 cm wide. For further description of the size and shape of the base material 22 in the tooth whitening system, please refer to

01811973.5 p.

US Patent Application 09/268185 filed on March 15, 1999, the content of which is fully incorporated herein by reference. Although the carrier 26 shown in FIG. 1 should have at least the same size and shape as the substrate 22, it is the size of the substrate that the carrier 26 shown in FIG. 4 can exceed, so that it is easier to remove the substrate 22 and the substrate from the carrier 26.Thin layer24. Thin layer 24.

The base material 22 should have a low bending stiffness so that it can cover the outer surface of the teeth with a small amount of force; that is, it can keep the curvature of the user's mouth, teeth and gaps between the teeth consistent. Because the remaining force in the base material to restore it to its original flat shape is very small. The flexibility of the substrate allows it to be adjacent to the soft tissue for a long time without physical stimulation. The substrate does not need pressure to make it rest against the teeth, and when applied, it easily fits on the surface of the teeth and the space between the teeth without permanent deformation.

Bending stiffness is a material property, which is a function of the combination of the thickness, width, and elastic modulus of the material. The test method is used to measure the stiffness of polyalkenyl films and sheets. It uses a strain gauge at the end of a horizontal beam to determine the bending resistance of the sample. The other end of the horizontal beam presses on the sample belt, forcing a part of the belt to deform into the vertical groove of the horizontal platform where the sample belt is placed. The microammeter connected to the strain gauge is calibrated to indicate the number of grams of deformation force. The stiffness of the sample can be directly read from the microammeter, and its unit is grams per centimeter of the sample tape width. In a preferred embodiment of the present invention, which is not required, the bending stiffness of the soft substrate is less than 5 g/cm (measured on Handle-0-Meter, #211-300, purchased from Phi.1 adelphia, PA Thwing-Albert Instrument Co., the test method used is ASTM D2923-95). The preferred bending stiffness of the substrate 22 is less than about 4 g/cm, more preferably less than about 3 g/cm, and most preferably about 0.1 g/cm to 1 g/cm.

For tooth whitening compositions, it is often necessary to include a humectant as a component of the composition. Wetting agents can provide rheology and/or physical stability, and can also provide users with various aesthetic effects. However, for common humectants, such as polyols (such as glycerin, sorbitol, polyethylene glycol, propylene glycol), the stability of active peroxides will be affected by high concentrations of humectants (especially in the presence of polyester ) Adverse effects. Therefore, according to the present invention, the concentration of polyol in the thin layer 24 of the tooth whitening composition is less than about 40% by weight of the tooth whitening composition, preferably about 0%-35%, more preferably about 1%-30%, and most It is preferably about 5% to 15%. In addition, these low-concentration polyols are preferably formed from a material other than polyester when the tooth whitening composition in contact with the surfaces 28 and 30 of the carrier 26 and/or the substrate 22 is formed from a polyolefin base. In the case of use.

As the concentration of polyols decreases, the water concentration included in other substances in the tooth whitening composition is about 85% to 99%, preferably about 70% to 95%, more preferably about 70% of the total weight of the tooth whitening composition. -90

01811973.5 The %. This water concentration includes the free water added plus the amount of water introduced along with other materials. A composition with an increased amount of water improves the stability of the peroxide, because this is related to the liquid phase and the physicochemical state (such as the gas/liquid equilibrium state) in the composition. When the water concentration rises, it replaces glycerin. When the water concentration increases, the molar ratio of peroxide to water decreases. This reduces the equilibrium concentration of peroxide in the gas phase. In a system with a fixed headspace (such as in package 34 of Figure 3), the total amount of peroxide in the gas phase is less. The peroxide reacts in the gas phase. Therefore, reducing the concentration of polyol reduces the reaction rate in the gas phase. This will also slow down the decomposition of peroxide in the gel phase, because it is the container that maintains the headspace balance. Therefore, increasing the water concentration in the formulation will slow down the chemical decomposition reaction in the liquid phase and also slow down the decomposition in the gas phase, thereby maintaining a higher peroxide concentration for a given period of time.

According to another aspect of the present invention, it has been found that the stability of the thin layer 24 of the tooth whitening composition can be improved by appropriately selecting the exposed surface area and volume of the thin layer 24. As mentioned above, the term "exposed surface area" refers to the side surface area of the thin layer of tooth whitening composition 24 (for example, indicated by the number 50 in the figure), which is directly exposed to the head space 32 of the closed package 34 (Figure 34), and the volume It refers to the volume of the thin layer 24 of the tooth whitening composition. As mentioned above, the term "headspace" refers to the empty volume in the package 34 (ie, does not include the tooth whitening system). For example, a thin layer 24 that is 5 mm long, 5 mm wide, 0.1 mm thick, and has only side surfaces 50 exposed to the head space 32, has an exposed surface area of 0.2 mm 2 and 0.25 mm³volume of. The ratio of the exposed surface area of the thin layer 24 to the volume of the thin layer 24 is less than about 0.15 mmτ, more preferably about 0.05-0. 15 mm], most preferably less than about 0.05-0. 1 mmτ .

The packaging 34 can be of various shapes and sizes. However, the shape and size of the packaging 34 need to be well adapted to the shape and size of the tooth whitening system 20. The packaging may be in the form of a bag, box, plastic container, envelope, bag or other suitable packaging known in the art. Many packages 34 and the tooth whitening system 20 can be bundled together or formed into a group in other ways, so that the tooth whitening system can be adequately supplied to meet the needs of multiple days of use. The volume of the head space 32 of the package 34 is preferably about 0.1 to 30000 mm³, More preferably, the ratio of the volume of the head space 32 to the volume of the thin layer 24 of about 50-10000 mm J is 1 to about 500, preferably 1 to about 400. The ratio of the volume of the head space 32 to the volume of the thin layer 24 is preferably 1 to about 200, and most preferably 1 to about 100. The packaging 34 should be composed of an opaque, low or no water vapor permeability and generally impermeable material. . The packaging 34 may be composed of one or more materials, and may also have a liner. For example, the bag can be constructed from a sheet of metal foil and have a polyethylene liner. Other suitable materials that are opaque and resistant to vapor penetration include plastic, paper, metal foil, cardboard, polymers, and rubber. One more available

01811973.5 The largest package (not shown in the figure) to store many packages 34.

Now let's look at Figures 4-6 to describe a preferred embodiment of the present invention that minimizes the ratio of the exposed surface area to the volume of the thin layer 24. The tooth whitening system 120 includes a substrate 122 having a first portion 36 applied to the teeth and a second portion 38 remaining on the carrier 26. The first and second parts 36 and 38 are separated by a slit 40, which preferably penetrates the thickness of the substrate 122, but a fragile or other separation line (such as a perforated line or part A slit line) instead of the slit 40, so that the first and second portions 36 and 38 of the substrate 122 remain at least partially connected before the user completely separates them. The slit 40 is preferably substantially U-shaped in plan view, with two ends 42 extending from a common edge 44 of the substrate 122. Although this structure is preferred, it is believed that other slit structures can also be used. The first and second parts 36 and 38 of the substrate 122 respectively cover the first and second parts 46 and 48 of the thin layer 24 of the tooth whitening composition, which can be clearly seen in FIG. 6. In other words, the first part 46 of the tooth whitening composition is substantially coextensive with the first part 36 of the substrate 122, and the second part 48 of the tooth whitening composition is substantially coextensive with the second part 38 of the substrate 122 . The first and second parts 46 and 48 of the tooth whitening composition are preferably integral with each other, and are not separated until use, in order to improve the stability of the second part 42. Qualitative effect. However, it should be known that the first and second parts 46 and 48 of the tooth whitening composition will be partially or completely separated during the operation of forming the incision, which will be discussed in detail below. The ratio of exposed surface area to volume of the thin layer 124 of the tooth whitening composition in the tooth whitening system 129 is relatively smaller than the ratio of exposed surface area to volume of the thin layer 24 in the tooth whitening system 20, because the second part 48 is added. The volume of the thin layer of tooth whitening composition 124 is increased, and the increased surface area of the thin layer of tooth whitening composition 124 due to the addition of the second part 48 is relatively small.

Take a look at Figures 7 and 8, which show a tooth whitening system 220 according to another preferred embodiment of the present invention. The tooth whitening system 220 includes a substrate 22, a thin layer 24 of a tooth whitening composition, and a carrier 226 having recesses 52. The thin layer 24 of the tooth whitening composition is substantially surrounded by the recesses 52 and a portion of the substrate, so that the ratio of the exposed surface area to the volume of the thin layer 24 is very small. In fact, the exposed surface area of the thin layer 24 is zero because it is completely surrounded by the recesses 52 and the substrate 22, so that no tooth whitening composition is exposed to the head space of the package. The substrate 22 and the carrier 126 are preferably directly adjacent to the outside of the recess 52 as shown in FIG. 8, but it is conceivable that the substrate 22 can only extend to the edge of the recess 52.

Look at Figure 9, which shows another preferred embodiment of the present invention. The tooth whitening system 320 includes a carrier 26, two substrates 22A and 22B, and a thin layer of a tooth whitening composition (not shown in the figure). Base material 22A

01811973.5 Numbers and 22B are preferably adjacent to minimize the size of the package in which the tooth whitening system 320 is stored. The size and shape of the substrates 22A and 22B should be selected so that the ratio of the exposed surface area to the volume of the tooth whitening composition is the above-mentioned value. According to the shape and size of the substrate, the substrates 22A and 22B may be separated by a slit. Likewise, the thin layer may be integrally formed or separated by a slit. As described above with respect to the tooth whitening system 20, the substrates 22A and 22B may be the same or different shapes. In the case that there is more than one substrate in one package 34, the exposed surface area and volume of the tooth whitening composition in the tooth whitening system are the sum of the two thin layers 24A and 24B that connect the two substrates in the package. .

In addition to the above-mentioned embodiments, another composition containing active peroxide can be added to the top space of the package to increase the exposed surface area of the tooth whitening system, thereby improving the stability of the active peroxide in the thin layer 24 of the tooth whitening composition. Sex. In the example of FIG. 11, the tooth whitening system 420 may include one or more sets of peroxide-containing compositions 54 having surfaces exposed to the head space of the package. These groups 54 can be thin-film, hemispherical, polyhedral, or any other shape and size. Although these groups 54 are shown on the carrier 26 ±, one or more groups may be on the inner wall 56 of the package (see, for example, FIG. 3), or one or more groups may be in the top space 32 of the package 34 On a sheet or another carrier.

According to another aspect of the present invention, it has been found that the stability of the active peroxide can be improved by appropriately selecting the non-exposed surface area and volume of the thin layer 24. Here, the term "non-exposed surface area" refers to the surface area that is not directly exposed to the top space of the package, such as the surface area 31 adjacent to the substrate 22 and the carrier 26 (Figure 2) ο The ratio of the non-exposed surface area to the volume of the thin layer 24 Less than about 105 cm1, preferably about 40-100 cm1, most preferably about 60-85 cmΛ. Generally, the polyol concentration of the tooth whitening system is less than about 40%, and the exposed surface area to volume ratio of the thin layer 24 is less than about 0.15 The ratio of the unexposed surface area to the volume of the millimeter Ι thin layer is less than about 105 cm τ, or the material forming the surface of the substrate 22 and the carrier 26 in contact with the tooth whitening composition is polyalkenyl. This tooth whitening system is being manufactured After the next 12 months, the concentration of active peroxide is about 45-70% of the initial concentration. After 12 months of manufacture, the active peroxide concentration of this tooth whitening system can also be about 50-60% of the initial concentration. It was found that the concentration of polyols can be reduced or the exposure of the thin layer 24 can be reduced. The surface area to volume ratio maximizes the stability of active peroxides. By replacing the carrier and substrate materials and reducing the non-exposed surface area to volume ratio of the thin layer, the stability of the active peroxide can only be improved to a lesser extent.

The concentration of one or more polyols in the tooth whitening system is less than about 40%, the exposed surface of the thin layer 24

01811973.5 The ratio of the first product to the volume is less than about 0.15 mmT, the ratio of the non-exposed surface area to the volume of the thin layer is less than about 105 cm, and the material forming the surface of the substrate 22 and the carrier 26 in contact with the tooth whitening composition is Polyolefin, this kind of tooth whitening system 12 months after manufacture, its active peroxide concentration is about 45-100% of the initial concentration. After 12 months of manufacture, the active peroxide concentration of this tooth whitening system can also be about 45-85% of the initial concentration. In other embodiments of this tooth whitening system 12 months after manufacture, the concentration of the active peroxide is about 50-75%, or about 50-70% of the initial concentration.

Look at Figure 11, which shows a preferred method of forming a tooth whitening system 120. This method can also be used to make other preferred tooth whitening systems described herein. The sheet 60 for the carrier 26 is unwound from the cotton 62 and sent to the drum 64. The sheet 60 for the carrier 26 can be manufactured by some known film manufacturing methods. The sheet 60 for the carrier 26 (and the sheet 66 for the substrate 22) can be formed by some known film manufacturing methods. The sheets 60 and 66 can be prepared by a blow molding method or a casting method. Extrusion methods and other methods that do not affect the bending stiffness of the substrate can also be used. The nozzle 68 sprays the tooth whitening composition in the form of a thin layer 70 on the sheet 60 for the carrier 26 ±o the sheet 66 for the substrate 22, unwinding from the cotton 70, and lightly presses it on the thin layer of the tooth whitening composition. On layer 70, a three-layer laminate is formed. This laminate is fed into the cotton 72, so that the slit 40 is formed, and the sheet 66 for the base material 22 and the thin layer 70 of the tooth whitening substance 22 are cut through. The outer edges 74 of the second parts 38 and 48 that form them (Figure 5). After the operation of cutting through and forming slits on the cotton 72, the weizi 76 is used to take up the excess sheet 66 for the substrate 22, so as to leave the first and second parts of the substrate 22 and the carrier 26. The tooth whitening composition on the sheet 60. The eiko 78 cuts through the carrier 26 to form an independent tooth whitening system 120. When the conveyor 82 is used to collect these tooth whitening systems 120, the tooth whitening system 120 can be taken up by the surplus carrier 26, and then the tooth whitening system can be placed in the package 34 to form a packaged peroxide product. These steps can be rearranged, some can be omitted, or steps known in the prior art can be added.

Generally, after manufacturing, the tooth whitening system 20 is stored in the packaging 34 (and/or the second packaging) for at least about 12 months. The storage should be stored at about 20-45°C and protected from light, but at least part of the storage time (usually Is 2-4 months) can be in the refrigerator. The tooth whitening system is more preferably stored in the dark at about room temperature. After storage, the user can open the package 34 and take out the tooth whitening system from the package 34. After storage, the tooth whitening composition is applied to the teeth using the substrate 22, and at least a part of the teeth (preferably all the teeth) will be whitened. In this patent, the term "whitening" refers to the use of the CIE LAB test method described in the present invention,

01811973.5 The resulting increase or change in tooth color.

After storage, the tooth whitening composition is applied to the teeth for about 5-120 minutes, preferably about 30-60 minutes per day. Generally, it is at least once a day for about 7-28 consecutive days, and more preferably twice a day for about 7-14 days. The application time and number of days within this specification depends on many factors, including the degree of whitening or bleaching required, the user's teeth, whether the initial whitening is required or the whitening is maintained. Therefore, the total number of applications is about 1 to 42 times, more preferably about 5 to 28 times. After storage for 12 months, and after applying the tooth whitening composition according to the above specifications for the number of times and duration, the value provided by the tooth whitening system is less than or equal to: about -1, about 1.25, or about -2, where minus The sign description is along the negative direction of the b* axis (ie the decrease of yellow in the CIE LAB color space). The value is more preferably about -1.25 to about -5, and the most preferable value of Ab* is about 1-2 to about -5. The AL value provided by this tooth whitening system is less than or equal to: about -1, about 1.25, about -1 1.5 or about -2, where the negative sign indicates the negative direction along the L axis (that is, the increase in the CIE LAB color space brightness). The 4L value is more preferably about 1.25 to about -1, and the 4L value is most preferably about 1-2 to about -5.

The Aa* value provided by this tooth whitening system is about 1-3 to about +3, where the positive and negative signs indicate the positive and negative directions along the a* axis, respectively. Because the color of the teeth changes with the region due to dietary reasons, the value will increase or decrease correspondingly with the region. The value (defined in this technique as the square root of the square sum of AL, z\a* and the value) is about 1 to about 7.7 Examples In the following table, some preferred examples of the tooth whitening composition of the present invention are given. All the components in the following tooth whitening composition should be uniformly mixed.

01811973.5 p.

<td></td><td>1</td><td>2</td><td>3</td><td>4</td><td>5</td><td>6</td>

<td>glycerin</td><td>10. 000%</td><td>10. 000%</td><td>20. 000%</td><td>10. 000%</td><td>—</td><td>One</td>

<td>water</td><td>67. 776%</td><td>64. 348%</td><td>54. 348%</td><td>64. 248%</td><td>74. 148%</td><td>67. 776%</td>

<td>Hydrogen peroxide (35% solution)</td><td>15. 143%</td><td>18.571%</td><td>1&amp; 571%</td><td>18.571%</td><td>18.571%</td><td>15. 143%</td>

<td>Carboxypolymethylene</td><td>4. 500%</td><td>4. 500%</td><td>4. 500%</td><td>4. 500%</td><td>4. 500%</td><td>4. 500%</td>

<td>Sodium hydroxide (50% solution)</td><td>2.000%</td><td>2.000%</td><td>2.000%</td><td>2.000%</td><td>2.000%</td><td>2.000%</td>

<td>Saccharin Sodium</td><td>One</td><td>——</td><td>—</td><td>0. 100%</td><td>0. 200%</td><td>One</td>

<td>Sodium Stannate</td><td>0. 200%</td><td>0.200%</td><td>0. 200%</td><td>0.200%</td><td>0. 200%</td><td>0. 200%</td>

<td>Sodium Pyrophosphate</td><td>0. 381%</td><td>0.381%</td><td>0. 381%</td><td>0. 381%</td><td>0. 381%</td><td>0.381%</td>

<td>Propylene Glycol</td><td>—</td><td>—</td><td>—</td><td>——</td><td>—</td><td>10. 000%</td>

<td>Pluronic407</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—-</td>

<td></td><td>7</td><td>8</td><td>9</td><td>10</td><td>11</td><td>12</td>

<td>glycerin</td><td>10. 000%</td><td>—</td><td>3.000%</td><td>15. 000%</td><td>10. 000%</td><td>10. 000%</td>

<td>water</td><td>68. 157%</td><td>57.276%</td><td>72.576%</td><td>63.076%</td><td>72.919%</td><td>66. 955%</td>

<td>Hydrogen peroxide (35% solution)</td><td>15. 143%</td><td>15. 143%</td><td>17. 143%</td><td>15. 143%</td><td>—</td><td>17. 143%</td>

<td>Carboxypolymethylene</td><td>4. 500%</td><td>—</td><td>4. 500%</td><td>4.500%</td><td>4. 500%</td><td>4. 500%</td>

<td>Sodium hydroxide (50% solution)</td><td>2.000%</td><td>2.000%</td><td>2.200%</td><td>1. 700%</td><td>2.000%</td><td>—</td>

<td>Saccharin Sodium</td><td>—</td><td>—</td><td>—</td><td>——</td><td>—</td><td>—-</td>

<td>Sodium Stannate</td><td>0. 200%</td><td>0. 200%</td><td>0. 200%</td><td>0. 200%</td><td>0. 200%</td><td>—</td>

<td>Sodium Pyrophosphate</td><td>—</td><td>0. 381%</td><td>0. 381%</td><td>0. 381%</td><td>0. 381%</td><td>—</td>

<td>Propylene Glycol</td><td>One</td><td>—</td><td>—</td><td>―-</td><td>—</td><td>—</td>

<td>Pluronic407</td><td>—</td><td>25.000%</td><td>—</td><td>—</td><td>—</td><td>One</td>

<td>Potassium hydroxide</td><td>One</td><td>One</td><td>—</td><td>—</td><td>—</td><td>1.403%</td>

<td>Peroxidant glands</td><td>—</td><td>—</td><td>——</td><td>—</td><td>10. 000%</td><td>—</td>

01811973.5 Method for determining the percentage and concentration of active peroxide The percentage and concentration of active peroxide described here are measured using the following method. Store packages containing peroxide systems for a specified period of time (such as 12 months) and conditions. After the storage time is specified here, the peroxide concentration is determined by iodine titration. The iodine titration method is a standard method for measuring peroxide concentration known in the prior art. Generally, the substrate and the active peroxide-containing composition are first weighed, and then the composition is dissolved in 1M sulfuric acid, and the peroxide is reacted with excess potassium iodide in the presence of methacrylate. Then use starch indicator and titrate with known concentration of sodium thiosulfate to a clear end point. After the titration is completed, the substrate is weighed, and the weight difference is used to obtain the weight of the composition. The peroxide concentration in the composition is then calculated. When the storage time is long, the active peroxide can also be measured as above after at least 120 days, and then the first-order reaction kinetics method known in the prior art can be used to extrapolate the concentration after the remaining time. The above measurement method should be carried out immediately after the peroxide product is manufactured, but also after the designated storage time is over, in order to determine the absolute concentration of the peroxide and the percentage of the initial concentration retained.

The method of measuring whitening is here, whitening can be measured according to the 1976 CIE LAB color space method, where the L value represents the brightness and varies between 100 (completely white) and 0 (black). When the a* value is positive, it means red, when it is 0, it means gray, and when it is negative, it means green. When the b* value is positive, it means yellow, when it is 0, it means gray, and when it is negative, it means blue. Here L, a*, b* can be measured with a spectrophotometer known in the prior art. Before whitening, a certain light condition is used for the first measurement, and after whitening, the same light condition is used for the second measurement. Measurements. A suitable spectrophotometer is Photo Research Spectrascan PR650 (produced by Photo Research, Inc. of Chatsworth, CA). Use a white light source to provide light. The light source should provide vertically polarized light, such as using a polarizer. A suitable polarizer is HN 38 polarizer (manufactured by 3M Corporation in Minneapolis, MN). Other polarizers can also be used, such as infrared reflective filters (filters that increase the color temperature of the light source). A suitable light source is provided by Crystal Falls, Produced by Dedo Electric of MI, it is equipped with a 150 watt, 24 volt Xenophot HLX bulb (manufactured by Osram, Germany). Other polarized white light sources can also be used as known methods. The light sources are placed 14 inches apart, and the spectrophotometer is located between the light sources. The light source is focused on a chin rest, which is 12 inches away from the lens of the spectrophotometer. The size and placement of the light source, spectrophotometer and frequency holder can be changed to adapt to the focal characteristics of different spectrophotometers. Near light

01811973.5 The first 45 degree angle is focused on the top. The spectrophotometer is set in L*, a*, b* modes, and is calibrated with a white standard. In order to measure the color of the teeth, the subject placed its chin on the frequency support and used a lip retractor to pull the back of the cheek so that the light source would shine on the teeth.

The two whitening tests are performed by focusing the spectrophotometer on the center of the teeth and performing the whitening test to test the color characteristics of the subject's teeth. For most tooth whitening systems, the central maxillary incisor is the whitened tooth. If the tooth whitening system is used to whiten more than one central maxillary incisor, each measurement can only measure the L, a*, and b* values of no more than four central maxillary incisors (the tooth whitening system is applied on). The L, a*, and b* values of the four central maxillary incisors are averaged to arrive at a set of L, a*, and b* values. The first measurement is performed before the tooth whitening system is applied, and the second measurement is performed after the tooth whitening system is applied and removed (for example, after whitening occurs). The value of Aa\Ab* is the difference between the second and first measurement results.

Although some specific embodiments of the present invention have been described, it is obvious that those skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention. All modifications within the scope of the present invention include In the appended claims.

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