Tooth whitening strips

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DESCRIPTION

Tooth whitener strips

Technical Field of the Invention

The present invention relates to teeth whitening strips, and more especially, teeth whitening strips having a bleaching 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, chewing gum, whitening in clinics and, more commonly, bleaching solutions that are used with a bucket and are obtained without a doctor's or dentist's prescription. Teeth whitening products are known in the art that use a strip of material together with an active chemical bleaching substance. For example, in US-6,419,906 it describes a tooth whitening product comprising a strip of material formed from a polymer that can be hydrated with water and a dental bleaching agent. Although these whitening products may work for their intended purposes, there is a continuing desire to improve the efficacy, stability and aesthetic properties of these teeth whitening products.

In US-6 419 906 B1 a thin and flexible film is described which, when applied to stained teeth, is hydrated with saliva and is effective in such a way to whiten teeth. The film comprises a polymeric matrix of anhydrous ethylene oxide that can be hydrated with water, which contains a solid peroxide bleaching agent. After application to the stained dental surfaces, the peroxide whitening agent dissolves with the saliva present in the oral cavity with a whitening activity of the active substance when the film is placed and placed on the teeth.

Methods and systems for teeth whitening are taught in US-2002/012685 A1. The methods include the steps of providing a flexible strip of material, applying a layer of a tooth whitening substance having an active whitening substance to a front surface of a plurality of teeth, adapting the strip of material to the front surface of the plurality of teeth and adapt the strip of material to interstitial spaces between the plurality of teeth. The strip of the material serves as a protective barrier for the active tooth whitening substance for a period of time sufficient for the active tooth whitening substance to act on the plurality of the teeth. The delivery systems include a strip of material sized to cover a front surface of a plurality of teeth, in which the strip of material is substantially flat and has sufficient flexibility to accommodate the front surfaces of the plurality of teeth and the teeth. interstitial spaces between them during use. The delivery systems further include a layer of a tooth whitening substance in contact with the strip of material.

Summary of the invention

A tooth whitening product is provided that includes a band formed from a plurality of fibers that are arranged to provide a plurality of empty spaces. A polymer coating that can be hydrated with water that has a dental bleaching agent is deposited on the web.

Brief description of the drawings

Although the specification concludes with claims that are especially related and clearly claim the invention, it is believed that the present invention will be better understood in view 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, not in accordance with the present invention, in which a coating of a dental bleaching agent has been applied to the film;

Fig. 2 is a perspective view of an embodiment of a tooth whitening product of the present invention, in which the tooth whitening product comprises a band and a coating that completely links the empty spaces of the band and in which a part of the coating has been removed to reveal the characteristics shown below;

Fig. 3 is a side cross-sectional view of the tooth whitening product of Fig. 2, in which the empty spaces are shown as partially filled;

Fig. 4 is a side cross-sectional view of the tooth whitening product of Fig. 2, in which the empty spaces are shown as completely filled;

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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 links the void spaces of 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 link the void spaces of the band;

Detailed description of the achievements

Next, the preferred embodiments of the present invention will be detailed, examples thereof being illustrated in the accompanying drawings, in which the equal numbers indicate the same elements in the different views and in which the elements having the same last two digits (e.g., 20 and 120) suggest similar elements. The present invention relates to teeth whitening products in the form of a film or strip and comprising a dental bleaching agent and a polymer that can be hydrated with water. Preferably, the polymer that can be hydrated with water is also, at least partially, water soluble (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 can be used with other teeth whitening products, such as dental cuvettes. Polymers that can be hydrated with water suitable for use with the present invention include ethylene oxide polymers, homopolymers or mixtures of ethylene oxide polymers of various molecular weights ranging from about 10,000 Daltons and 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 by different sources. Poly (ethylene oxide) in the molecular weight range of 10,000 to 1,000,000 Daltons is marketed by the Union Carbide Company under the trade name of "Polyox." Other polymers that can be hydrated with water include polypropylene oxide, poly (ethylene oxide), Carbopol, polyvinyl alcohol, ethyl vinyl acetate, sodium alginate, methyl methacrylate, xanthan gum, pectin, pululane, guar gum, agar, polyvinyl pyrolidone (PVP), carrageenan, celluloses (e.g. eg, hydroxypropyl cellulose, hydroxyethyl cellulose, hydroxypropylmethyl cellulose and hydroxymethyl cellulose) and mixtures thereof. Although the thickness of the film may vary, as described more fully below, the film may have a thickness between 0.1 micrometers and 1500 micrometers (µm).

Saliva hydration of the polymer that can be hydrated with water in the oral cavity dissolves the bleaching agent incorporated in the polymer matrix. Then, the bleaching agent is released from the tooth whitening product to the dental surfaces to which the film is applied. Bleaching agents suitable 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. Preferred persulfates are oxones.

Optionally, the polymer that can be hydrated with water 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 its series of Carbowaxes ranging in molecular weight from 200 to 600 Daltons. Other plasticizers include cellulose esters, sebacate esters, castor oil, tricresyl phosphate and adipate phthalate.

In an embodiment outside the scope of the present invention, a tooth whitening product 20 comprises a polymer film 22 that can be hydrated with water and a solid whitening agent that has been applied as a coating 24 to a face of the film 22 of polymer that can be hydrated with water, as shown in Fig. 1. The solid dental bleaching agent can be applied while the film is still viscous or after the film has dried or cured. The application of the dental bleaching agent in this manner reduces the exposure of the dental bleaching 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 polymer that can be hydrated with water and the dental bleaching agent compared to a film that can be hydrated with water having a dental bleaching agent dispersed throughout it. In addition, 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 dental bleaching agent towards the dental surface since the coating is directly adjacent and / or is in contact with the dental surface during use. Suitable solid teeth whitening agents that can be applied to a face of a polymer film that can be hydrated with water include carbimide peroxide, calcium peroxide, percarbonate, sodium percarbonate, perborates, persulfates and mixtures thereof. These teeth whitening agents can be sprayed, gravure applied, nebulization grind, drop spray and other processes known in the art.

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The coating of the solid dental bleaching agent can cover all or a part of the polymer film that can be hydrated with water. The thickness of the coating may be greater than about 0.001 micrometers, or greater than about 0.005 micrometers, or greater than about 0.01 micrometers or greater than about 0.05 micrometers, or greater than about 0.1 micrometers, or greater than about 1 micrometer, or greater than 5 micrometers and / or less than about 100 micrometers, or less than about 50 micrometers, or less than about 10 micrometers, or less than about 1 micrometer. 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 250 mg / cm2, or less than about 100 mg / cm2, or less than about 10 mg / cm2. Other materials may be mixed with the solid dental bleaching agent or applied sequentially before or after the application of the solid dental bleaching agent. For example, binders, adherents, starches, sweeteners and flavorings, colorants (e.g., to help distinguish the active face from the non-active face of the strip) and other active substances for oral care can be applied as part of the oral care. application stage Although the solid dental bleaching agent can be applied dry, it is contemplated that a solvent with the dental bleaching agent can be used during application. In one embodiment, a solvent that dissolves both the polymer that can be hydrated with water and the dental bleaching agent can be employed by applying the dental bleaching agent on the surface of the film that can be hydrated with water. In this process, the dental bleach is dissolved in the solvent and then applied to the surface of the film that can be hydrated with water so that the dental bleaching agent is dispersed, at least partially, into the film since the solvent can Dissolve a part of the movie. Alternatively, the solvent can only dissolve the dental bleaching 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 dental bleaching agent at a given temperature but do not dissolve the polymer that can be hydrated with water at that temperature. Some examples include Cellosolve acetate, anisole, 1,4-dioxane, ethyl acetate, ethylenediamine, dimethyl Cellosolve, Cellosolve solvent, ethanol, Carbitol solvent, n-butanol, Cellosolve cuil, n-butyl acetate, 2- Propanol and methyl Cellosolve.

The film 22 of the polymer that can be hydrated with water can be prepared using conventional extrusion, calendering, pressing or solvent molding processes. For example, to prepare a film by solvent casting poly (ethylene oxide), 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 and homogeneous solution has been formed, followed by the addition of the bleaching agent and any other ingredient, such as saporiferous. 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 entire 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, kraft paper impregnated with polyethylene. The drying of the film can be carried out in a high temperature air bath using a drying oven, drying tunnel, vacuum dryer or any other suitable drying equipment, after which the dental bleaching agent can be sprayed on the film. .

The efficacy and / or stability of the dental bleaching agent can be increased by forming the film that can be hydrated with water with a solvent other than water such that the dental bleaching agent does not come into contact with water during the forming process and no water remains. residual in the subsequent manufacture of the film. Here, 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. Here, the term "efficacy" is intended to refer to the amount of dental bleach per unit of time. In one process, the polymer that can be hydrated with water and the dental bleaching agent are mixed and then fed to an extruder whose screw, through a mechanical action, melts the polymer that can be hydrated with water. Then, the molten polymer is extruded into a film that takes the form of the tooth whitening product.

The effectiveness of the dental bleaching 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 polymer film that can be hydrated with water further comprises water-insoluble organic and / or inorganic additives to reduce the amount of polymer that can be hydrated with water so that the solution of the dental bleaching agent is maximized during use. Suitable water insoluble organic materials include polyolefins (e.g., 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 from 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

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with water it 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 crushed before incorporation into the film. In one embodiment, the average particle size of the water insoluble additives is at least about 1 micrometer, or at least about 20 micrometers, or at least about 25 micrometers and / or less than about 100 micrometers, or less than about 50 micrometers , or less than about 25 micrometers, or less than about 10 micrometers. In addition to reducing the amount of polymer that can be hydrated with water that is available to react with the tooth whitening agent, the concentration of the tooth whitening agent available on the surface of the teeth can be increased during hydration, since more water is available to dissolve the tooth whitening agent instead of hydrating or otherwise dissolving the polymer that can be hydrated with water. The dental bleaching agent can be mixed with the polymer that can be hydrated with water as described in US.

6,419,906 or coated on the film as previously described.

In the present invention, a band, mesh or weft is incorporated into the tooth whitening product to improve hydration in the film. The band, mesh or weft can be formed from fibers that are aligned in random or repeat geometric designs. Referring to Fig. 2, a tooth whitening product 120 is illustrated comprising a band 32. The band 32 is formed from fibers 34 that are arranged in a geometric repeat design. The fibers can be formed from one or more polymers that can be hydrated with water and can have a dental bleaching agent incorporated therein. Alternatively, the fibers can be formed from water insoluble materials, in which case, the web will operate in a manner similar to that of the previously described films incorporating water insoluble materials. The fibers are arranged so as to provide empty spaces 36 between the fibers. The empty spaces can facilitate the hydration of the band 32 and therefore the dissolution of the dental bleaching agent. The empty spaces may vary in size or have a substantially constant size on the band. For example, empty spaces 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 1 micrometer, or at least 5 micrometers, or at least 10 micrometers, or at least 20 micrometers, or at least 50 micrometers and / or less than 200 micrometers, or less than 100 micrometers, or less than 50 micrometers, or less than 20 micrometers. The separation 38 between fibers is at least 1 micrometer, or at least 5 micrometers, or at least 10 micrometers, or at least 20 micrometers, or at least 50 micrometers, or at least 1 mm, or at least 1.5 mm and / or less than 5 mm, or less than 2.5 mm, or less than 1.5 mm, or less than 50 micrometers.

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. The band 32 can be formed from a polymer that can be hydrated with water or other material, such as polymers (eg, polypropylene, polyethylene, etc.) and cellulose. The fibers 34 of the band 32 may be arranged in a repeat or random design. The coating 44 comprises a polymer that can be hydrated with water and a dental bleaching agent. Other materials may be included in the coating, such as a plasticizer, water, water insoluble additives, etc. The coating can bond the empty spaces 36 in such a way that a substantially solid layer is formed in the band 32. The coating can completely fill the empty spaces as shown in Fig. 3 or partially fill in the empty spaces as shown in Fig. 4 with respect to the tooth whitening product 320. When the empty spaces are partially filled, the gap 50 that is formed can facilitate the hydration of the band and consequently the dissolution and release of the dental bleaching agent. Alternatively, the coating 44 can only partially link the empty spaces, as shown in Fig. 5 for the teeth whitening product 420. In yet another embodiment, a coating 44 does not link the empty spaces 36 of the band 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 dental bleaching agent within the coating and / or the fibers and the amount of polymer that can be hydrated with water can vary in these embodiments of bands depending on the extent to which the coating links the empty spaces and / or covers the fibers, and based on the desired dissolution rate of the dental bleaching agent. As will be appreciated, any combination of full filling of the voids, partial filling of the voids, partial linking of the voids and coating of the fibers in one embodiment can be provided.

The above-described embodiments of the present invention can also be combined with other layers such as a thin layer of protective coating, e.g. eg, from 10 nanometers (nm) to 500 micrometers (µm) thick. The coating material is applied in a layer thin enough so as not to interfere with the flexibility of the film and to allow the bleaching strip to adapt to an arrangement of a row of teeth. The coating materials may 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, acetate Cellulose and polyvinyl alcohol derivatives, such as polyvinyl acetate and shellac.

The dental bleach products of the present invention can be packaged in bags as individual strips or a roll of film can be provided in a tape-type dispenser, in which the individual strips can be cut from the roll for use in the oral cavity, or it can be provide the film with perforations or other

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fragility characteristics to allow the separation of strips of predetermined length of the film roll. Optionally, the tooth whitening product of the present invention may further include a removable coating. The removable coating can be formed from any material that exhibits less affinity for the film and / or band, which the film or band presents by itself. The removable coating 5 can be formed from polymer films, paper, sheets, fabric, nonwovens and other suitable materials known in the art. Optionally, the removable coating may include a coating, such as wax, silicone, Teflon®, fluoropolymers, etc. The films of the present invention can be formed directly in the removable coating. The removable coating can be cut to the desired size before or after the film is formed immediately. The teeth whitening products of the present invention can

10 also provided in the form of a coating for dental cuvettes, such as those described in US 5,098,303, in which the strips are incorporated in the groove of the dental cuvette.

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 tooth whitening product is formed so that it has a suitable width to cover a row of teeth (upper or lower). Accordingly, the tooth whitening product can be applied to the upper set of teeth or to the lower set of teeth separately or simultaneously. The length of the tooth whitening product is determined by the amount of coverage desired. In this sense, the number of teeth to be bleached will determine the dimensions of the product. For example, you may want to bleach only the incisors, which are the ones that look the most

twenty easily by others. Therefore, in this case, the length of the tooth whitening product can be reduced, compared to the case in which 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 dental bleaching 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.

25 of the principles of the invention, as well as its practical application and thus allowing the person skilled in the art to use the invention in various embodiments and with various modifications as appropriate with the particular use contemplated. All these modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the extent to which they have a fair, legal and equitable right.

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