Untitled record

ES 2 704 462 T3

DESCRIPTION

Strips for teeth whitening

Technical field of the invention

The present invention relates to teeth whitening strips, and more especially to teeth whitening strips having a whitening agent incorporated therein.

Background of the invention

Teeth whitening has become very popular in recent years. More and more consumers choose to whiten their teeth. Teeth whitening options include toothpastes, mouthwashes, gum, clinic whitening, and most commonly whitening solutions that are used with a tray and are available without a prescription or from a dentist. Tooth whitening products are known in the art that use a strip of material in conjunction with a chemical whitening active. For example, US Patent 6,419,906, the main part of which has been incorporated by reference herein, describes a tooth whitening product comprising a strip of material formed from a polymer that can be hydrated with water and a teeth whitening agent. Although these whitening products may function for their intended purposes, there is a continuing desire to improve the efficacy, stability, and aesthetic properties of these tooth whitening products.

Summary of the invention

Teeth whitening products are provided. A tooth whitening product includes a film formed from a water-hydratable polymer and a plasticizer, wherein the water-hydratable polymer comprises polymers of ethylene oxide, polypropylene oxide, Carbopol, polyvinyl alcohol, alginate sodium, xanthan gum, pectin, pullulan, guar gum, agar, polyvinylpyrrolidone, carrageenan, hydroxypropylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, hydroxymethylcellulose, and mixtures thereof. The film has a first side and a second side and a tooth whitening agent coated on one side of the film, wherein said tooth whitening agent is applied as a solid.

Brief description of the drawings

Although the specification concludes with claims which specifically refer to and clearly claim the invention, it is believed that the present invention will be better understood in light of the description taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a side cross-sectional view of a tooth whitening product according to the present invention, wherein a coating of a tooth whitening agent has been applied to the film;

Fig. 2 is a perspective view of another embodiment of a tooth whitening product of the present invention, wherein the tooth whitening product comprises a band and a coating that completely bridges the void spaces of the band and where it has been removed a portion of the coating to reveal the features below;

Fig. 3 is a side cross-sectional view of the tooth whitening product of Fig. 2, where the voids are shown as partially filled;

Fig. 4 is a side cross-sectional view of the tooth whitening product of Fig. 2, showing the voids as completely filled;

Fig. 5 is a perspective view of another embodiment of a tooth whitening product of the present invention, wherein the tooth whitening product comprises a band and a coating that partially bridges the gaps in the band;

Fig. 6 is a perspective view of another embodiment of a tooth whitening product of the present invention, wherein the tooth whitening product comprises a band and a coating that does not bridge the gaps in the band;

Fig. 7 is a side cross-sectional view of another embodiment of a tooth whitening product of the present invention comprising a perforated film; and Fig. 8 is a perspective view of another embodiment of a tooth whitening product of the present invention comprising a first layer and a second layer.

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Detailed description of the realizations

Next, the preferred embodiments of the present invention will be detailed, examples thereof being illustrated in the attached drawings, in which the like numbers indicate the same elements in the different views and in which the elements having the same last two digits (eg, 20 and 120) suggest similar elements. The present invention relates to tooth whitening products in the form of a film or strip and comprising a tooth whitening agent and a polymer that can be hydrated with water. Preferably, the water-hydratable polymer is also at least partially soluble in water (ie, only a part of an added polymer dissolves in water). Although the present invention will be described herein with respect to these films or strips, it is contemplated that the present invention may be used with other tooth whitening products, such as dental trays. Suitable water hydratable polymers for use with the present invention include ethylene oxide polymers, homopolymers, or blends of ethylene oxide polymers of various molecular weights ranging from about 10,000 Daltons to up to about 10,000,000 Daltons and preferably in the range of about 100,000 to about 1,500,000 Daltons. Such ethylene oxide polymers are marketed from different sources. Polyethylene oxide in the 10,000 to 1,000,000 Dalton molecular weight range is marketed by the Union Carbide Company under the trade name "Polyox." Other polymers that can be hydrated with water include Polypropylene Oxide, Polyethylene Oxide, Carbopol, Poly (Vinyl Alcohol), Sodium Alginate, Xanthan Gum, Pectin, Pullulan, Guar Gum, Agar, Polyvinylpyrrolidone (PVP), Carrageenan , celluloses, ie, hydroxypropylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, and hydroxymethylcellulose, and mixtures thereof. While the thickness of the film can vary, as described in greater detail below, the film can have a thickness between about 0.1 microns and about 1500 microns (pm).

Saliva hydration of the water-hydratable polymer in the oral cavity dissolves the bleaching agent incorporated into the polymer matrix. The whitening agent is then released from the tooth whitening product to the tooth surfaces to which the film is applied. Suitable bleaching agents for the practice of the present invention include peroxides, metal chlorites, perborates, percarbonates, peroxyacids, persulfates, and combinations thereof. Suitable peroxide compounds include hydrogen peroxide, urea peroxide, calcium peroxide, and mixtures thereof. Suitable metal chlorites include calcium chlorite, barium chlorite, magnesium chlorite, lithium chlorite, sodium chlorite, and potassium chlorite. The preferred chlorite is sodium chlorite. A preferred percarbonate is sodium percarbonate. The preferred persulfates are oxones.

Optionally, the water hydratable polymer can be mixed with a plasticizer. Suitable plasticizers include glycols such as propylene glycol, polyethylene glycol, polyhydric alcohols such as glycerin and sorbitol, and glycerol esters such as glycerol triacetate. Glycerin can be used as well as propylene glycol or polyethylene glycol, as marketed by Union Carbide Corporation as their Carbowax series ranging in molecular weight from 200 to 600 Daltons. Other plasticizers include cellulose esters, sebacate esters, castor oil, tricresyl phosphate, and adipate phthalate.

In one embodiment of the present invention, a tooth whitening product 20 comprises a polymer film 22 that can be hydrated with water and a solid bleaching agent that has been applied as a coating 24 to one side of the polymer film 22 that can be hydrated. with water, as shown in Fig. 1. The solid tooth whitening agent can be applied while the film is still viscous or after the film has dried or cured. Applying the tooth whitening agent in this way reduces the exposure of the tooth whitening agent to any amount of water that may have been used as a solvent in film formation and also reduces the amount of contact between the water-hydrating polymer and tooth whitening agent compared to a water-hydrating film that has a tooth whitening agent dispersed throughout. Furthermore, this embodiment has an increased concentration of the tooth whitening agent on the surface that is applied to the teeth. Such a coating can also aid in the unidirectional diffusion of the tooth whitening agent towards the tooth surface since the coating is directly adjacent and / or is in contact with the tooth surface during use. Suitable solid tooth whitening agents that can be applied to one side of a polymer film that can be hydrated with water include carbimide peroxide, calcium peroxide, percarbonate, sodium percarbonate, perborates, persulfates, and mixtures thereof. These tooth whitening agents can be sprayed, applied by gravure, spray grinding, drop spray, and other processes known in the art.

The solid tooth whitening agent coating may cover all or a portion of the water-hydratable polymer film. The coating thickness can be greater than about 0.001 microns, or greater than about 0.005 microns, or greater than about 0.01 microns, or greater than about 0.05 microns, or greater than about 0.1 microns, or greater than about 1 micron, or greater than 5 microns and / or less than about 100 microns, or less than about 50 microns, or less than about 10 microns, or less than about 1 micron. The dose per unit area of ​​the tooth whitening agent is at least about 0.001 mg / cm², or at least about 0.005 mg / cm², or at least about 0.01 mg / cm², or at least about 0.05 mg / cm², or at least about 0.1 mg / cm², or at least about 1 mg / cm², or at least about 10 mg / cm², or at least about 100 mg / cm² and / or less than about 500 mg / cm², or less than about

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250 mg / cm², or less than about 100 mg / cm², or less than about 10 mg / cm². Other materials can be mixed with the solid tooth whitening agent or applied sequentially before or after application of the solid tooth whitening agent. For example, binders, adherents, starches, sweeteners and flavors, colorants (e.g., to help distinguish the active side from the non-active side of the strip), and other oral care actives can be applied as part of the application stage. Although the solid tooth whitening agent can be applied dry, it is contemplated that a solvent can be used with the tooth whitening agent during application. In one embodiment, a solvent may be employed that dissolves both the water-hydratable polymer and the tooth whitening agent by applying the tooth-whitening agent to the surface of the water-hydratable film. In this process, the teeth whitening agent is dissolved in the solvent and then applied to the surface of the film which can be hydrated with water so as to disperse the teeth whitening agent, at least partially, within the film since the solvent can dissolve a part of the film. Alternatively, the solvent can only dissolve the tooth whitening agent, in which case a separate coating would form on one side of the film after evaporation or removal of the solvent. Suitable solvents could include solvents that can dissolve the tooth whitening agent at a given temperature but do not dissolve the polymer that can be hydrated with water at that temperature. Some examples include anisole, 1,4-dioxane, ethyl acetate, ethylenediamine, ethanol, Carbitol solvent, n-butanol, n-butyl acetate, 2-propanol, and the solvents Cellosolve ethylene glycol mono-N-propyl ether, ethylene glycol monobutyl ether and ethylene glycol n-butyl ether acetate.

The water hydratable polymer film 22 can be prepared using conventional extrusion, calendering, pressing or solvent casting processes. For example, to prepare a solvent cast polyethylene oxide film, the ethylene oxide polymer or polymer blend is dissolved in a sufficient amount of a solvent that is compatible with the polymer. Examples of suitable solvents include water, alcohols, acetone, ethyl acetate, or mixtures thereof. After a solution has formed, a plasticizer is added with stirring and heat is applied if necessary to aid dissolution, until a clear, homogeneous solution has formed, followed by the addition of the bleaching agent and any other ingredients. , such as flavors. The solution is coated on a suitable carrier material and dried to form a film. The carrier material must have surface properties that allow the polymer solution to spread evenly across the width of the intended carrier without splashing to form a destructive bond between the two substrates. Examples of suitable carrier materials include glass, stainless steel, Teflon, polyethylene impregnated kraft paper. Drying of the film can be done in a high temperature air bath using a drying oven, drying tunnel, vacuum dryer or any other suitable drying equipment, after which tooth whitening agent can be sprayed onto the film. .

In another embodiment of the present invention, the efficacy and / or stability of the tooth whitening agent can be increased by forming the water-hydratable film with a solvent other than water such that the tooth whitening agent does not come into contact with water during the forming process and there is no residual water left in the subsequent manufacture of the film. As used herein, the term "stability" is intended to refer to the predisposition of a material to maintain its original structure or concentration over a fixed period of time. As used herein, the term "efficacy" is intended to refer to the amount of tooth whitener per unit of time. In one process, the water-hydratable polymer and tooth whitening agent are mixed and then fed to an extruder whose screw, through mechanical action, melts the water-hydratable polymer. The molten polymer is then extruded into a film that takes the shape of the tooth whitening product.

The effectiveness of the teeth whitening agent can also be increased by reducing the amount of polymer that can be hydrated with water that forms the film. In one embodiment, the water-hydratable polymer film further comprises water-insoluble inorganic and / or organic additives to reduce the amount of water-hydratable polymer so that solubilization of the tooth whitening agent is maximized during use. Suitable water-insoluble organic materials include polyolefins (eg, polyethylene, polypropylene, polybutenes, polyisoprenes, and copolymers thereof) and polyester. Suitable water insoluble inorganic materials include calcium phosphate, calcium pyrophosphate, titanium dioxide, and silica. Water insoluble additives may comprise at least about 10%, or at least about 20%, or at least about 30% and / or less than about 90%, or less than about 80%, or less than about 70% or less. of about 50% or less than about 40%, or less than about 30% by weight of the film. In these embodiments, the amount of polymer that can be hydrated with water is at least about 5%, or at least about 10%, or at least about 20%, or at least about 30% and / or less than about 90%, or less than about 80%, or less than about 70% by weight of the film. Water insoluble additives can be ground prior to incorporation into the film. In one embodiment, the average particle size of the water insoluble additives is at least about 1 micron, or at least about 20 microns, or at least about 25 microns and / or less than about 100 microns, or less than about 50 microns. , or less than about 25 microns, or less than about 10 microns. In addition to reducing the amount of water-hydratable polymer that is available to react with the tooth whitening agent, the concentration of the available tooth whitening agent on the surface of the teeth can be increased during hydration, since more water is available to dissolve. the teeth whitening agent instead of hydrating or otherwise dissolving the polymer that can be hydrated

ES 2 704 462 T3 with water. The tooth whitening agent can be mixed with the polymer which can be hydrated with water as described in US-6,419,906 or coated onto the film as previously described.

In yet another embodiment of the present invention, a band, mesh or web is incorporated into the tooth whitening product to enhance hydration in the film. The web, mesh, or weft can be formed from fibers that are aligned in repeating or random geometric patterns. Referring to FIG. 2, a tooth whitening product 120 is illustrated comprising a band 32. Web 32 is formed from fibers 34 that are arranged in a repeating geometric pattern. The fibers can be formed from one or more polymers that can be hydrated with water and can have a tooth whitening agent incorporated therein. Alternatively, the fibers can be formed from water-insoluble materials, in which case the web will function in a similar manner to previously described films incorporating water-insoluble materials. The fibers are arranged so as to provide void spaces 36 between the fibers. The voids can facilitate the hydration of the band 32 and thus the solubilization of the tooth whitening agent. The voids can vary in size or have a substantially constant size on the web. For example, voids may be smaller in one region and larger in another region, depending on the desired hydration rate. The fibers 34 may have a diameter of at least about 1 micron, or at least about 5 microns, or at least about 10 microns, or at least about 20 microns, or at least about 50 microns and / or less than about 200 microns, or less than about 100 microns, or less than about 50 microns, or less than about 20 microns. The spacing 38 between fibers is at least about 1 micron, or at least about 5 microns, or at least about 10 microns, or at least about 20 microns, or at least about 50 microns, or at least about 1mm, or at least about 1.5mm and / or less than about 5mm, or less than about 2.5mm, or less than about 1.5mm, or less than about 50 microns.

In an alternative embodiment, a tooth whitening product 220, shown in Fig. 3, comprises a band 32 having a coating or layer 44 applied thereto. Web 32 can be formed from a polymer that can be hydrated with water or other material, such as other polymers (eg, polypropylene, polyethylene, etc.) and cellulose. The fibers 34 of the web 32 may be arranged in a repeating or random pattern. Coating 44 comprises a polymer that can be hydrated with water and a tooth whitening agent. Other materials can be included in the coating, such as a plasticizer, water, water-insoluble additives, etc. The coating can bond the voids 36 such that a substantially solid layer is formed on the web 32. The coating can completely fill the voids as shown in Fig. 3 or partially fill the voids as shown in Fig. 4 with respect to the tooth whitening product 320. When the voids are partially filled, the gap 50 that is formed can facilitate hydration of the band and consequently the solubilization and release of the tooth whitening agent. Alternatively, the liner 44 can only partially bridge the voids, as shown in Fig. 5 for teeth whitening product 420. In yet another embodiment, a coating 44 does not link the voids 36 of the web 32 but simply covers the fibers 34, partially or completely, as shown by way of example in FIG. 6 for the tooth whitening product 520.

The concentration of the tooth whitening agent within the coating and / or fibers and the amount of polymer that can be hydrated with water can vary in these banding embodiments depending on the extent to which the coating bridges the voids and / or covers the gaps. fibers, and based on the desired solubilization rate of the tooth whitening agent. As will be appreciated, any combination of full void filling, partial void filling, partial void bonding, and fiber coating can be provided in one embodiment.

In a related embodiment, a perforated film may be provided without a band or mesh, as shown in Fig. 7. A monolayer or multilayer film comprising a polymer that can be hydrated with water could be provided in the teeth whitening product 620. , a teeth whitening agent and a plasticizer. The film can be punctured once it has dried or cured. The voids, holes, or openings 630 that are formed during the drilling process may pass completely through the thickness of the film or could only partially penetrate the thickness of the film. The hollow spaces 636 may have the same dimensions as previously described with respect to the hollow spaces in the band. The hollow spaces 636 can be provided in a random or repeating pattern, and can vary in size and shape as described above. In addition, this embodiment may include a coating of a tooth whitening agent as described above or other features of the embodiments described above.

In another embodiment of the present invention, a tooth whitening product 720 is provided in the form of a laminated film as shown in Fig. 8. The laminated film comprises two or more layers comprising water-hydratable polymers. A first layer 64, to be applied to the teeth, further comprises a tooth whitening agent. The water hydratable polymer comprises at least about 1%, or at least about 10%, or at least about 20%, and / or less than about 90%, or less than about 70%, or less than about 50% by weight of the first layer. The tooth whitening agent comprises at least about 1%, or at least about 10%, or at least about 15% and / or less than about 70%, or less than about 60%, or less than about 50% by weight of

ES 2 704 462 T3 the first layer. The remainder of the first layer may comprise water or other materials, such as the water insoluble additives described above or a plasticizer. The second layer 66, which is located adjacent to the lips and / or cheeks during use, preferably does not comprise a teeth whitening agent. The water-hydratable polymer of the second layer 66 comprises at least about 20%, or at least about 30%, or at least about 40%, and / or less than about 100%, or less than about 90%, or less than about 80% by weight of the second layer. A plasticizer comprises at least about 0.1%, or at least about 1%, or at least about 2% and / or less than about 40%, or less than about 30%, or less than about 20% by weight of the Second layer. The remainder of the second layer 66 may comprise other materials, such as water, water-insoluble additives, or oral care actives, other than a teeth whitening agent. Examples of other oral care actives suitable for use in the present invention include phosphates (eg, pyrophosphates, polyphosphate, polyphosphonates, and mixtures thereof), fluoride ion sources, antimicrobial agent, anti-inflammatory agents, nutrients, and enzymes. These oral care actives are described in more detail in US Patent 6,096,328 (and the patents cited therein), the main part of which has been incorporated by reference herein. These other active oral care substances could also be incorporated into a film comprising only one layer and formed from a polymer that can be hydrated with water (e.g. g., polyethylene oxide) and a plasticizer, the basic formation of which is described in US Pat. No. 6,419,906.

The composition of the first layer 64 and the second layer 66 of the tooth whitening product 720 can be tailored to provide different functionalities. For example, the first layer 64 may comprise less polymer that can be hydrated with water than the second layer 66 so that the first layer 64 hydrates more rapidly thereby solubilizing the tooth whitening agent more quickly and efficiently (i.e., providing greater concentration more quickly). The second layer may contain relatively more of the polymer that can be hydrated with water so that it functions as a barrier layer that prevents diffusion of the solubilized tooth whitening agent from the tooth while at the same time still allowing some hydration from the posterior face of the tooth product. teeth whitening. Also, since the second outer layer comprises more polymer that can be hydrated with water, it will remain in a film-like state for longer than the first layer 64 so that the tooth whitening agent will have a longer period of time to act on the teeth. teeth. The absence of the tooth whitening agent from the second layer could also improve tissue tolerability since the peroxide source would not be directly adjacent to the soft tissue of the lips and cheeks. The teeth whitening product 720 can be formed by casting the first layer first, followed by the second layer casting on top of the first layer before or after the first layer has dried or cured. The layers can be pressed together by rollers aligned so that there is a parting line through which the first and second layers pass. The first and second layers can comprise the same polymer that can be hydrated with water or different polymers that can hydrate with water.

In another aspect of the present invention, there is provided a film comprising a polymer that can be hydrated with water and a tooth whitening agent in a thin form and a higher concentration of the tooth whitening agent. The thickness of the film is at least about 1 pm, or at least about 5 pm, or at least about 10 pm, or less than about 15 pm and / or less than about 2 mm, or less than about 1 mm, or less than about 0.5 mm, or less than about 0.25 mm, or less than about 0.1 mm, or less than about 20 pm, or less than about 15 pm. The concentration of the tooth whitening agent is at least about 1%, or at least about 10%, or at least about 15%, or at least about 20%, or less than about 25% and / or less than about 70%, or less than about 60%, or less than about 50%, or less than about 40%, or less than about 30%. Surprisingly, these increased levels of tooth whitening agent concentration can be utilized while maintaining acceptable soft tissue tolerability without the need for cumbersome rubber pads or other artificial soft tissue barriers. As used herein, the term "artificial barrier" is intended to refer to any physical means that prevents or is intended to prevent a tooth whitening agent from migrating to the soft tissue adjacent to the tooth during the whitening operation. Other artificial barriers can include light-hardened resins. As used herein, the term "soft tissue tolerability" is intended to refer to the degree to which a user experiences a sensation often described as burning or stinging or experiencing irritation of the gingival tissues. This sensation can range from minor to severe. In addition, one or more layers, preferably without a tooth whitening agent, can be provided adjacent to the previously described layer containing the tooth whitening agent.

The above-described embodiments of the present invention can be further combined with other layers such as a thin protective coating layer, e.g. eg, 10 nanometers (nm) to 500 microns (um) thick. The coating material is applied in a thin enough layer not to interfere with the flexibility of the film and to allow the whitening strip to conform to a tooth row arrangement. Coating materials can be one, or a combination of high molecular weight (i.e., molecular weights greater than 1,000,000 Daltons) and include, ethyl cellulose, propyl cellulose, isopropyl cellulose, butyl cellulose, t-butyl cellulose, cellulose acetate and derivatives of polyvinyl alcohol, such as polyvinyl acetate and shellac.

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The teeth whitening products of the present invention may be bagged as Individual strips or a roll of film may be provided in a tape-type dispenser, wherein the individual strips may be cut from the roll for use in the oral cavity, or it may the film should be provided with perforations or other brittle characteristics to allow separation of strips of predetermined length from the roll of film. Optionally, the teeth whitening product of the present invention may further include a release liner. The release liner can be formed from any material that has less affinity for the film and / or web than the film or web itself exhibits. The release liner can be formed from polymer films, paper, sheets, fabric, nonwovens, and other suitable materials known in the art. Optionally, the release coating can include a coating, such as wax, silicone, Teflon®, fluoropolymers, etc. Films of the present invention can be formed directly on the release liner. The release liner can be cut to size before or after film formation. The teeth whitening products of the present invention may also be provided in the form of dental tray liners, such as those described in US-5,098,303, the main part of which has been incorporated by reference herein, wherein the strips have been incorporated into the groove of the dental tray.

To use the teeth whitening products of the present invention, when the film is applied to the surface of the teeth and hydrated with saliva in the oral cavity, or pre-moistened by immersing the strip in water, it will adhere to the teeth. in an appropriate way. In this sense, the teeth whitening product is formed to have a suitable width to cover a row of teeth (upper or lower). Accordingly, the teeth whitening product can be applied to the upper set of teeth or the lower set of teeth separately or simultaneously. The length of the teeth whitening product is determined by the amount of coverage desired. In this sense, the number of teeth to be whitened will determine the dimensions of the product. For example, it may be desired to whiten only the incisors, which are the ones most easily seen by others. Therefore, in this case, the length of the tooth whitening product can be reduced, compared to the case where it is desired to whiten all the teeth. The duration of the application of the product on the teeth will depend on the type and concentration of the tooth whitening agent, as well as the type and intensity of the intrinsic or extrinsic stain.

The embodiments described herein have been chosen and described to provide the best illustration of the principles of the invention, as well as their practical application, and thus enable the person skilled in the art to use the invention in various embodiments and with various modifications according to is suitable for the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted to the extent that they have a fair, legal and equitable right.