CZ20002944A3 - Light-activated bleaching teeth composition and method of use - Google Patents

Abstract

The teeth whitening composition has a translucent first component which is a carrier compound and a translucent second component which is an oxidizing compound which, when applied to stained teeth and exposed to actinic radiation, is activated to facilitate whitening of the teeth. A method for light-activated teeth whitening comprises applying a teeth whitening composition to at least one tooth and exposing said composition to actinic radiation to activate the oxidizing compound, the teeth whitening device having a light source, at least one optical output, projection means for holding and positioning the optical output outside the patient's mouth in such a manner as to provide substantially simultaneous and uniform illumination of the patient's anterior teeth by said optical output; and coupling means for coupling said light source to the optical output.

Description

Technical field

This invention relates to improvements in tooth whitening compositions and methods of use thereof. In particular, the invention provides novel tooth whitening compositions and methods that utilize light energy to achieve faster and better levels of tooth whitening.

This application claims priority from Provisional Application No. 60/074,708, filed February 13, 1998, and No.

60/075,222, filed February 19, 1998, the contents of which are incorporated herein by reference.

State of the art

White teeth have long been considered cosmetically desirable. Unfortunately, due to the presence of chromogenic (staining) substances in foods, beverages, tobacco, and saliva, as well as internal sources such as blood, amalgam fillings, and antibiotics such as tetracycline, if left untreated, teeth become almost permanently stained. The tooth structures that are generally responsible for the appearance of a stained appearance are enamel, dentin, and the acquired pellicle. Enamel is primarily composed of inorganic material, mostly in the form of hydroxyapatite crystals, and contains approximately 5% organic material, primarily in the form of collagen. In contrast, dentin is composed of about 20% collagen, including proteins, with the remainder consisting of inorganic material, mostly hydroxyapatite crystals, similar to those found in enamel. The resulting pellicle is a protein* layer on the surface of tooth enamel that quickly re-forms after intensive tooth brushing.

A tooth stain classification system has been proposed, referred to as the N (Nathoo) classification system, (J. of Amer. Dental Asso., vol. 128, special supplement (April 1997)). One form of direct tooth stain is the NI stain type, which occurs when a chromogenic material binds to the tooth surface, causing a color similar to the unbound chromogen. Another type of direct tooth stain is the N2 stain type, in which the chromogenic material binds to the tooth surface and subsequently undergoes a color change upon adhesion to the tooth. Finally, the N3 stain is an indirect tooth stain, caused by the adhesion of a colorless material (prechromogen) to the tooth, said prechromogen undergoing a chemical reaction to convert into a chromogen that causes the tooth stain. Tooth stains can be either extrinsic or intrinsic, depending on their location in the tooth structure. For example, extrinsic staining of the acquired pellicle results from compounds such as tannins and other polyphenolic compounds becoming trapped in close association with the protein layer on the tooth surface. This type of staining can usually be removed by mechanical dental cleaning methods that remove all or part of the acquired pellicle along with the accompanying staining. In contrast, intrinsic staining occurs when chromogens or prechromogens penetrate the enamel and dentin and become closely associated with the tooth structure. Intrinsic staining can also arise from systemic sources of chromogens or prechromogens, for example, when excess fluoride absorbed during enamel development results in the mottled yellow or brown spots typical of fluoride staining. Internal staining is not amenable to mechanical tooth cleaning methods and generally requires the use of chemicals, such as hydrogen peroxide, which can penetrate the tooth structure to cause a change in the light absorption of chromogens. Internal tooth staining is generally more stubborn and difficult to remove than external tooth staining.

Consequently, tooth whitening compositions generally fall into two categories: (1) gels, pastes, or liquids, including toothpastes, which are mechanically moved back and forth over the surface of stained teeth to effect removal of tooth discoloration by abrasive disruption of the stained pellicle; and (2) gels, pastes, or liquids that achieve a whitening effect on the tooth by a chemical process upon contact with the stained tooth surface for a period of time, after which the composition is removed. In some cases, an auxiliary chemical process or additive, which may be oxidative or enzymatic, assists the mechanical process.

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Among the chemical strategies capable of removing or disrupting tooth discoloration, the most effective compositions contain an oxidizing agent, such as hydrogen peroxide, to attack the chromogen molecule in a manner that restores colorlessness, water solubility, or both. In one of the most popular approaches to whitening a patient's teeth, a dental professional creates a custom-made teeth whitening mold for the patient from a made impression of the patient's teeth and prescribes the use of an oxidizing gel, which is placed in the teeth whitening mold and worn for a period ranging from about 2 weeks to about 6 months, depending on the severity of the tooth discoloration. These oxidizing compositions, usually packaged in small plastic syringes, are applied directly by the patient to the custom-made teeth whitening mold, held in the mouth for a contact time of more than about 60 minutes and sometimes longer, up to 8 to 12 hours. The slow rate of whitening is largely due to the nature of the formulations that are developed to maintain the stability of the oxidizing composition. The most commonly used oxidizing compositions contain the precursor of hydrogen peroxide, carbamide peroxide, which is mixed with an anhydrous or hygroscopic viscous carrier with a low water content, containing glycerin and/or propylene glycol and/or polyethylene glycol. Upon contact with water, carbamide peroxide dissociates into urea and hydrogen peroxide. The concomitant slow rate of whitening in the hygroscopic carrier currently available in tooth whitening compositions causes tooth hypersensitivity in over 50% of patients. Tooth sensitivity is believed to be the result of fluid movement through the dentinal tubules, which are sensitive to nerve endings in the tooth. Carriers for Peroxide φφ φφ '· . φ φφ φφ Φ·

-φ φ φ φ φφφ φ φ φ φφφ φ φφφφφ • φφφ φ · φφφφφφ φ φφφφφ • ΦΦΦ φ

Prolonged exposure of teeth to bleaching agents, as currently practiced, has many adverse effects associated with tooth sensitivity. These include the solubility of calcium from the enamel layer at pH below 5.5 in association with demineralization; penetration of intact enamel and dentin by bleaching agents to the point of creating a comminuted cavity in the living tooth, with the risk of damage to the pulp tissue; dilution of bleaching compositions with saliva leading to leaching from the dental mold and subsequent ingestion.

Alternatively, there are oxidizing compositions (generally compositions with relatively high concentrations of oxidizing agents) that are applied directly to the surface of the patient's teeth in a dental office setting under the supervision of a dentist or dental hygienist. Theoretically, such a teeth whitening strategy yields faster results and better overall patient satisfaction; however, due to the high concentration of oxidizing agents contained in these so-called "outpatient" compositions, they can be dangerous to the patient and equally to the practitioner if not handled with care. The patient's soft tissues (gums, lips and other mucous membranes) must first be isolated from potential exposure to the active oxidizing agent by using a perforated rubber covering (known as a rubber dam) through which only the teeth are exposed. Alternatively, the soft tissue should be isolated from the oxidizing agents used in the whitening process by covering said soft tissue with a polymerizable composition that is shaped to conform to the profile of the gums and is subsequently cured by exposure to a high-intensity light source. Once the soft tissue is isolated and protected, the practitioner should apply the oxidizing agent directly to the stained tooth surfaces for the prescribed period of time or until a sufficient change in tooth color is achieved. Typical results have been obtained using an “outpatient tooth whitener, with or without heat activation, in a range of approximately 2 to 3 shades (measured with the VITA® Shade Guide, VITA® Zahnfarbik, Bad Sackingen, Germany).

The range of tooth shades in the VITA® Shade Guide ranges from very light (Bl) to very dark (C4). All 16 tooth shades create a range of colors between these two extremes on the lightness scale. Patient satisfaction with the teeth whitening procedure increases with the number of tooth shade changes achieved. Typically, the minimum generally acceptable change is about 4 to 5 VITA® shades.

Attempts have been made to activate peroxides with heat and/or light for the purpose of whitening teeth. U.S. Patent No. 4,661,070 discloses a method of whitening stained teeth which involves applying a concentrated solution of hydrogen peroxide to a ground cavity or surface of a stained tooth, followed by exposing the stained teeth to optical energy consisting of both ultraviolet and infrared light.

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4444 44 444 9444 44 44 light. The preferred wavelengths of light disclosed in this patent are from 320 to 420 nanometers and from 700 to 1200 nanometers, with light in the visible spectrum (wavelengths from 500 and 700 nanometers) suppressed. The method suffers from two serious disadvantages: (1) ultraviolet light can be dangerous to the patient and the practitioner alike, and (2) infrared light can cause irreversible pulpitis if not handled with care.

These disadvantages are partially described in U.S. Patent No. 4,952,142, which discloses a dental whitening composition that filters out ultraviolet light and has a temperature control mechanism. This patent also discloses the use of visible light with wavelengths ranging from 450 to 500 and 650 to 750 nanometers to produce a dark purple beam with a red tint that allows the composition to be targeted and focused.

U.S. Patent No. 5,032,178 discloses compositions and methods for improving the effectiveness of tooth whitening that utilize exposure to "optical energy, preferably in the visible wavelength range of 400 to 700 nanometers." The composition disclosed in this patent calls for the use of (1) an inert silica gel-based material, (2) a catalytic accelerator (either magnesium sulfate monohydrate or ferrous sulfate), (3) an agent for imparting thixoplasticity and thickening properties to the composition, such as cellulose ethers and methyl vinyl ethers, and (4) a means for indicating the completion of the tooth whitening procedure, including a redox color indicator for conversion from one color to another in response to the dissociation of hydrogen peroxide over a given period of time. The compositions disclosed herein are prior art. are homogeneously mixed and all required components, including the catalyst, are evenly dispersed throughout the mixture. The disclosed compositions are not highly translucent to light energy in the range of 400 to 700 nm, due to the presence of a high content of inorganic silica particles. Commercial compositions based on this patent (available under the trade name Shofu Hi-Lite® from Shofu Dental Corporation, Menlo Park, California) confirm that these preparations are not translucent to visible light, but rather completely opaque. Typical results obtained using such compositions and methods are about 2 to 3 VITA® shades of improvement in tooth color similar to that achieved with compositions that do not work with light energy in the teeth whitening process.

U.S. Patent No. 5,240,415 discloses a teeth whitening system comprising a multi-component kit, one of the required components of said kit being fumed silica. As described above, silica renders the aqueous composition relatively opaque to visible light energy. Using this type of composition, an improvement in tooth shade of about 2 to 3 VITA® shades can again be expected.

Recently, Ultradent Products, Inc., South Jordan, Utah, has introduced a commercial product called Opalescence Xtra for teeth whitening in a controlled dental office environment. This product is believed to be based on the disclosure in U.S. Patent No. 5,785,527. The commercial product is

supplied in a plastic syringe and described in the accompanying literature as a light-activated teeth whitening gel containing approximately 35% hydrogen peroxide. pH determination showed that the product has a neat pH of approximately 4.0 at 25°C. The product is thickened with a polymer to a smooth gel-like consistency. Additionally, as the product is marketed and described in U.S. Patent No. 5,785,527, it contains a bright orange pigment or dye (carotene) which appears to serve as a "photosensitizer." The manufacturer also claims that the photosensitizer is capable of absorbing light energy and converting it into heat energy, thereby enhancing the action of the peroxide as a teeth whitening agent. The presence of the photoabsorber in the above composition renders it relatively opaque at wavelengths from about 400 to 700 nm. Exposure of this composition to light energy between 400 and 700 nm results in a gradual orange color change, presumably due to the photobleaching effect of the hydrogen peroxide present. Comparative clinical results show an improvement in tooth color of about 3 to 4 VITA® shades, which is highly dependent on the contact time of the composition with the tooth surface, rather than on any particular light or heat activation regimen. Additionally, the low pH of the commercial product may cause a decrease in the microhardness of tooth enamel due to the dissolution of hydroxyapatite crystals (which may cause a pH of around 5.5 or less).

Devices for use in the light/heat activated teeth whitening procedure include the commercially available Union Broach Illuminator System from Union Broach,

Health/Chem Company, New York, New York State. This

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4444 44 444 4444 4 4 44 The device, as described by the manufacturer, provides direct full spectrum illumination to all teeth located in the front of the average adult's mouth. Unfortunately, this device does not uniformly illuminate all sixteen central teeth in the anterior upper and lower arches, relative to the arch of the dentition. This potentially increases uneven results. The longer the Union Broach device, the greater the amount of heat it produces, which is both uncomfortable for the patient and potentially harmful to the teeth.

There is therefore a need for improved compositions, methods and devices for whitening teeth that overcome the limitations of the prior art described above. There is a particular need for tooth whitening compositions and methods capable of whitening teeth that are rapid and safe, without damaging tooth enamel, dentin or gums. The compositions and methods of the present invention described herein satisfy these and other needs.

The essence of the invention

It is an object of the present invention to provide rapid and safe teeth whitening compositions and methods which can be activated or accelerated by the use of light energy.

Another object of the present invention is to provide a teeth whitening composition which reduces the treatment time required to obtain a given level of teeth whitening and which is satisfactory to both the patient and the dentist.

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Another object of the present invention is to provide tooth whitening compositions that are relatively transparent to light energy in the wavelength range that dental chromogens absorb to allow exposure of the tooth enamel surface to said light energy upon contact with said tooth whitening compositions.

Yet another object of the present invention is to provide tooth whitening compositions and methods whereby the extent of tooth whitening, depending on the types of tooth stains being removed, can be controlled by the duration, intensity and wavelength of exposure of actinic radiation to the tooth surface.

The present invention includes methods for whitening teeth in which a stained tooth surface is contacted with (i) a tooth whitening composition that is translucent to photoactive light and (ii) a photosensitizing agent that responds to wavelengths of light that are transmitted by the whitening composition and, upon contact with the composition and agent, the tooth is exposed to a biologically safe and effective level of photoactinic light to enhance the ability of the oxidizing compound in the whitening composition to effectively and rapidly whiten teeth.

Also disclosed and contemplated within the scope of the present invention are methods for whitening teeth in which a stained tooth surface is contacted with an oxidizing compound that is transparent to wavelengths of light that are absorbed by the tooth-colored chromogens and then the exposure of the treated tooth is biologically safe and effective and

levels of the same wavelengths of light for effective, rapid teeth whitening.

Also disclosed and contemplated within the scope of the present invention are the compositions and compounds described above and a tooth whitening device in which at least eight central teeth on both the upper and lower jaws of an adult human are simultaneously and uniformly illuminated with a biologically safe and effective level of actinic light for effective rapid tooth whitening.

Brief description of the images

Fig. 1: Schematic of a device for illuminating eight central teeth in both the upper and lower arches of an adult for use in a light-activated teeth whitening procedure.

Fig. 2: Schematic illustrating the position of two devices for illuminating the eight central teeth in both the upper and lower arches of an adult for use in a light-activated teeth whitening procedure.

Fig. 3: Comparison spectrum graph.

Fig. 4: Spectral curves of light attenuation.

Examples of embodiments of the invention

Detailed description of preferred embodiments of the invention • ·

This section describes in detail preferred embodiments of the subject invention. These embodiments are further intended to illustrate the invention but are not to be construed as limiting. Because the present description is directed to those skilled in the art and is not a textbook for the manufacture of tooth whitening compositions or their use or for apparatus for using such compositions, the basic concepts and standard features known to those skilled in the art are not set forth in detail. Details of the concepts, such as the selection of suitable materials of construction or ingredients, operating conditions or manufacturing techniques, etc., are known or readily ascertainable by those skilled in the art. Attention is directed to appropriate texts and references known to those skilled in the art for details of these and other concepts that may be required in practicing the invention; see, e.g., Kirk-Othmer's Encyclopedia of Chemical Technology, 4th ed., vol. 4 (1992), 13 (1995), 18 (1996), John Willey & Sons, New York; Goldstein and Garber, Complete Dental Bleaching, Quintessence Publishing Co, (1995); and the aforementioned Journal of the American Dental Association, Volume 128, Special Supplement, (April 1997), the disclosures of which are incorporated by reference herein to assist in the practice of the invention. The development of the inventive compositions and methods described herein is the result of the unexpected discovery that extremely rapid tooth whitening was made possible by actinic irradiation to permeate an oxidizing compound; which is placed directly on the tooth surface being bleached. This discovery is ~in contrast to all compositions heretofore known in the art which include light • · · é ···.·· Μ ~ 14 - 9 · · · ···· · • · · · * · « 9 9 9 9 9 9 9 9 9 9 9 9 9 9

9999 99 999 9999 99 '99 /or thermal/ absorbing additives dispersed directly and homogeneously with the oxidizing compound. The inventive compositions, on the other hand, allow actinic irradiation to achieve a stained tooth surface at a higher power density than prior art compositions that are specifically designed to absorb light. Actinic irradiation is thus more effectively utilized compared to prior art compositions and methods in which the compositions are both opaque to most wavelengths of light and are activated directly by actinic irradiation. Since the greatest oxidizing action is required in the few millimeters of tooth enamel and dentin on the tooth surface, the inventive compositions and methods are more effective in removing tooth discoloration, in many cases with lower levels of active oxidizing agents, therefore leading to safer compositions for use in the oral cavity.

For the purposes of this specification, the term actinic radiation refers to light energy capable of being absorbed by either an external photosensitive substance or a dental chromogen itself. For the purposes of this specification, photosensitive actinic radiation refers to light absorbed by a specific photosensitive substance, where chromosensitive actinic radiation refers to light absorbed by one or more dental chromogens. The terms "actinic radiation" and "actinic light" will be used interchangeably.

Also for the purposes of this specification, the term "translucent" means having greater than 70% light transmission of a specified wavelength or within a wavelength band. Furthermore, all percentages of the components of the composition are by weight unless otherwise indicated.

Various methods of application of the inventive tooth whitening compositions are effective, although methods that allow accumulation or concentration of the photosensitizer in the acquired pellicle, enamel or dentin (the three tooth structures primarily associated with most tooth discolorations) are generally preferred. This is most effectively accomplished by contacting the stained tooth surface with the photosensitizer prior to contacting the same stained tooth surface with the oxidizing composition. In this manner, the photosensitizer is able to penetrate the tooth structure and thus be present at the site of the dental chromogen(s) prior to contact with the oxidizing composition and prior to exposure to a source of actinic radiation.

Photosensitizers useful for achieving the desired teeth whitening effect include compounds capable of absorbing light energy in the biologically acceptable wavelengths described by safety limits for use in the oral cavity. Generally, such wavelengths are from about 350 nanometers (nm) to about 700 nm, and include a portion of the UVA spectrum (300 to 400 nm) and most of the visible light spectrum (400 to 700 nm). Examples of compounds that can ♦

convert light energy into either heat or chemical energy, include semiconductor particles (particularly nanometer-sized titanium dioxide and zinc oxide), benzophenone derivatives, benzotriazole derivatives, diketones (such as camphorquinone and benzil), complex metal ligands (such as ferric potassium oxalate, manganese gluconate and various metal-bisphosphonate chelates), phthalocyanine metal complexes and others. A specific example of a suitable photosensitive composition is an aqueous dispersion of zinc oxide with particles of size between 5 and 20 nanometers. Any molecule capable of absorbing photons of light in the wavelength range from about 350 nm to about 700 nm and subsequently capable of converting the energy of said photon of light into usable oxidation energy either alone or in the presence of an oxidizing agent is contemplated for use in the practice of the present invention.

It is preferred that the inventive photosensitizers have a molecular size, charge, pH, and hydrophobicity/hydrophilicity that permit effective penetration into the deeper structures of tooth enamel and dentin. The more readily the photosensitizer penetrates the tooth structure, the more likely it is that it will be converted into oxidative activity at or in close proximity to the chromogen itself upon exposure of the photosensitizer to actinic radiation of appropriate wavelength and energy. Photosensitizers having a molecular size, subsequent charge, pH, and/or hydrophobicity/hydrophilicity that prevent or limit penetration into the deeper tooth structures are * suitable for use in the practice of the present invention, but may be limited in removing or destroying chromogens located on the outer tooth surface (external staining).

Particularly preferred photosensitizers belong to the general class of complex metal ligands that absorb light in the range from about 350 nm to about 700 nm. For the purposes of the present disclosure, the term "ligand" refers to an organic molecule capable of complexing or associating with a metal ion in aqueous solution, such that the reactivity, solubility, or any other physical property of said metal ion is altered. Such complex metal ligands are also known as metal coordination complexes. Suitable metal ions include iron, manganese, copper, and other transition metal ions. Different valence states may be used or may be present simultaneously. The metal ions may be present in saliva, plaque, or in the resulting pellicle on the tooth surface. The metal ions may also contribute to certain types of tooth discoloration by forming oxides.

Suitable metal ion ligands include chelating agents capable of associating with the metal ions listed above in aqueous solutions, resulting in a water-soluble metal chelate complex that absorbs light between about .350 .nm. and 700 nm. Illustrative, but not limiting, examples of metal coordination complexes are formed by associating iron, manganese, and copper with chelators such as ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DETPA), nitrilotriacetic acid (NTA), 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetra(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), and polyols such as sorbitol, xylitol, mannitol, maltitol,

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9999 99 9999999 lactitol and other non-carboxylated polyhydroxy compounds, more fully described in EP 443 651, such disclosure incorporated herein by reference. Any organic multidentate chelating agent capable of forming a photoabsorbing coordination complex with a metal ion may be contemplated for use in these inventive compositions for methods of whitening tooth discoloration.

Many of the metal ligand complexes that have been developed have absorption spectra that are pH dependent; in general, such complexes will show a greater degree of absorption between 350 and 700 nm at pH greater than about 4.0, the light absorption in this range increasing with increasing pH. For example, the aqueous complex formed between 1-hydroxyethylidene1,1-diphosphonic acid and ferrous ions is essentially transparent to visible light at pH 3.0, but absorbs strongly in the spectral region between 350 and 500 nm as the pH increases toward 7.0.

In some cases, the photosensitizer precursor may be incorporated directly into the oxidizing compositions, where it does not readily absorb light in the visible region of the spectrum from 400 to 700 nm. However, upon contact with the tooth surface (if placed there with the oxidizing composition), the photosensitizer precursor may combine, for example, with a metal ion such as iron, present in saliva or found in the interstitial fluid of enamel and dentin, with the subsequent formation in situ, of an active photosensitizer capable of activating the oxidizing compound upon exposure to actinic radiation.

• · · · · · · ··· ·· ·· ·· ··· ··· ··

Of course, only those compounds that are still in a highly oxidizing environment are suitable for inclusion directly in the oxidizing composition. For example, such a compound is 1-hydroxyethylidene-1,1-diphosphonic acid (commercially available under the trademark Dequest 2010 and sold as a 60% active solution by Monsanto Corporation, St. Louis, Missouri).

The ability of certain metal chelates to act as photosensitizers has been reported in the literature by various workers. For example, Van der Zee et al. ("Hydroxy1 Radical Generation by a Light-Dependent Fenton Reaction" in Free Radical Biology & Medicine, 14, 105-113 (1993) described the light-mediated conversion of Fe(III) to Fe(II) in the presence of a chelating agent and hydrogen peroxide. Reduction of Fe(III) chelates by 300 nanometer light to yield Fe(II) was shown to proceed uniformly for about 30 minutes, with conversion to Fe(II) ranging from about 40% to about 80%, depending on the particular chelating agent studied. The Fe(II) thus initiated a Fenton-type degradation of its hydrogen peroxide to yield hydroxyl radicals, which trapped the radicals and were detected by electron spin resonance (ESR). It was not suggested or implied by the inventors that this photochemical reaction could be useful in the oxidation of chromophores such as those found in human tooth.

Useful oxidizing compounds include liquids and gels, preferably containing a peroxide or peroxyacid known in the art. These oxidizing compounds include, but are not limited to, hydrogen peroxide, carbamide peroxide, alkali metal peroxides, alkali metal peroxycarboxylates, and alkali metal perborates. Often, it may be desirable to use a peroxyacid such as peracetic acid (for example, when attempting to eliminate very stubborn tooth discoloration caused by tetracycline).

In JS.K21UI tposition whitening teeth. The peroxyacid may be included directly in the oxidizing composition (allowing translucency to light energy between about 350 and about 700 nm). Alternatively, the peroxyacid may be formed by combining two or more separate phases (one of which contains a peroxyacid precursor, such as glyceryl acetate and the other contains one of the oxidizing compounds described above) before application to the tooth surface. Preferably, the peroxyacid is formed in situ, by contact between the tooth surface and the peroxyacid precursor prior to application of the oxidizing compound; the peroxyacid is thus formed only on the stained tooth structure and in that structure, where it is most beneficial to the tooth whitening process. Suitable peroxyacid precursors include, but are not limited to, glyceryl triacetate, acetylated amino acids, acetylsalicylic acid and N,N,N',Ntetraacetylethylenediamine, vinyl acetate polymers and copolymers, acetylcholine, and other biologically acceptable acetyl compounds.

Oxidizing compounds are liquid, gel or solid compositions translucent to light of a wavelength capable of activating a photosensitizer on the tooth surface; the light energy would otherwise be attenuated by a film or layer of oxidizing φφ . ΦΦ Φ .ΦΦ .. · · ·9 · ' φ· ' · Φ Φ · * Φ' ··>'.·'·>· Φ .71- ··· · φφφφφ φ ΦΦΦ Φ Φ Φ Φ Φ Φ Φ Φ φ φ φ φ φφ φφφφ φφφφ φφφφ φφφφ φφφφ ·♦ φφ compounds between the source of actinic radiation and the photosensitizer on the tooth enamel surface. Since the tooth enamel is the site of tooth discoloration, the most effective method of tooth whitening will be achieved when most or all of the light energy reaches the photosensitizer on the tooth enamel surface. An example of a suitable composition that is transparent to light energy between 380 and 500 nm is a 6% hydrogen peroxide gel with a pH of about 7.0, which is thickened to a viscosity of approximately 100,000 mPas with neutralized carboxypolymethylene.

Another unexpected advantage of using an oxidizing composition that is translucent to actinic light is that certain wavelengths of light appear to be absorbed by dental chromogens in a manner that promotes their oxidation to a non-chromogenic state. Reflectance studies show that dentin and enamel transmit green light, reflect yellow/red light, and absorb blue light. While not wishing to be bound by any particular theory, light is absorbed by the molecules responsible for tooth color; therefore, dental chromogens may act in a manner similar to photosensitizers. Specifically, exposure to certain wavelengths can increase the energy level of the pi electrons of the carbonyl moiety (C=O), double bond (C=C), and conjugated double bond (C=C-C=C), making them more susceptible to attack by active oxidizing species such as perhydroxyl anion (HOO-), peroxyacid anions (RCOOO-), and radical species such as hydroxyl radical (HO*) and perhydroxyl radical (HOO*). To destroy or dissolve chromogens, the activation energies of the reactions • 4 49 4

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4449 49 between one of the above-described light-absorbing moieties and the active oxidizing agents must be overcome; therefore, light-assisted attack by the chromogen leads to more efficient destruction of the moieties of the molecule responsible for the occurrence of tooth discoloration by raising the energy states of electrons in certain chemical bonds in the light-absorbing molecule from the normal bonding pi orbital to the non-bonding pi orbital. Although in the less stable non-bonding pi orbital, the light-absorbing double bond has a significant single bond character and is much more susceptible to attack by oxidizing agents such as peroxides and peroxyacids. Theoretically, actinic light of a specific energy and wavelength, simply through the process described above, can utilize the dental chromogen molecule as a photosensitizer to enhance the effectiveness of a given oxidizing composition in contact with the aforementioned dental chromogen.

A light-activated method of tooth whitening, in accordance with a particular embodiment of the invention, comprises contacting the surface of the tooth enamel with a photosensitizer, further contacting the tooth surface treated with the photosensitizer with an oxidizing compound, and then exposing the tooth surface to light energy capable of activating the photosensitizer, which in turn activates the oxidizing compounds on the tooth enamel surface.

Another light-activated method of whitening teeth, in accordance with another embodiment of the present invention, comprises contacting the surface of the tooth enamel with an oxidizing compound containing a photosensitizer precursor, wherein it is seen that this *» · · · 4 φ · · * · ♦ • ·· Φ Φ < Φ Φ · φφ φ

ΦΦΦ » Φ ΦΦΦΦ • ΦΦΦΦ Φ Φ ΦΦ ΦΦ · φ · ΦΦ ΦΦΦΦ

The precursor absorbs actinic radiation in the range of 350 to 700 nm only after contact with the aforementioned tooth surface. As the photosensitizer precursor becomes a light absorber, the tooth surface is exposed to light energy capable of activating the now absorbent photosensitizer, which in turn activates the oxidizing bleaching compound on the tooth surface.

Another light-activated method of whitening teeth, in accordance with another embodiment of the present invention, comprises contacting the surface of the tooth enamel with an oxidizing compound and then exposing said tooth enamel surface to actinic radiation corresponding to the absorption wavelength of the tooth chromogen molecule. Preferred wavelengths of light in this embodiment include those between about 350 and about 700 nanometers, more preferred embodiments include those between about 380 and about 550 nanometers with the most preferred wavelengths being between about 400 and about 505 nanometers. In all of the above-described methods, the oxidizing composition must be translucent to the actinic radiation useful to allow light energy of the specific wavelength to reach the tooth surface and underlying structures.

Yet another light-activated method of teeth whitening, in accordance with another embodiment of the present invention, comprises contacting a tooth enamel surface with a peroxyacid precursor prior to contacting said tooth enamel surface with an oxidizing compound and subsequently exposing the tooth enamel surface to the peroxyacid precursor.

- 24 actinic irradiation described above. The peroxyacid precursor may be placed on the tooth surface together with or separately from the photosensitizer.

Stained teeth can be treated individually, for example, by directing light onto the surface of a single tooth using an optical fiber as a light guide. In that case, several stained teeth are sequentially exposed to light, the dentist or hygienist moving the light guide from tooth to tooth during the procedure. This process is both labor-intensive and time-consuming for the dentist or hygienist, as well as tedious for the patient. Alternatively, all stained teeth can be exposed to light simultaneously, either by direct illumination from a light source shaped substantially to the dental arch, or by indirect illumination from a light guide or device capable of illuminating all anterior teeth at once.

One such device for simultaneously and uniformly illuminating at least eight central teeth on the upper and lower arches is shown in Figure 1. This preferred embodiment has three linear optical output units 11, 12 and 13 precisely positioned on three anterior (towards the patient) planes 1, 2 and 3. In a more preferred six-strip embodiment, two three-strip devices are positioned one above the other, resulting in six optical output units anterior to the patient surface, as shown in Figure 2.

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4 4 4· 4 Ο

Although Figures 1 and 2 illustrate embodiments having 3 output units and 6 output units, it is contemplated that the device may have any number of outputs or emitters, from one to many. Each output unit consists of a separate fiber or fiber bundle that is ultimately connected to a light source. Embodiments having 3 or 6 output units are currently preferred for the device because they achieve completely uniform illumination of eight or more central teeth without excessive manufacturing problems or costs. More than six output units are of course feasible and may in fact be advantageous from the perspective of uniformity of illumination.

The front surfaces of the device are positioned to provide an output configuration such that the combined beams of light from each output unit are converted to illuminate at least eight central teeth of both the upper and lower arches or the total area from the incisors to the first molars in each half-arch, the total area being about 10.4 cm ² in the average male. Although Figure 1 is shown in terms of form as linear, these output units may be of any shape, for example round, triangular or linear. Linear forms are preferred, preferred embodiments having six linear output units, each output unit having a length to width ratio of about 16 ± 20%, i.e. a ratio of from 12.8 to 19.2.

In the most preferred embodiments, 80% of the light projected from the output units onto the 8 upper and lower central teeth is within a region between about 22.9 and '· · wide

- 26 «· · . » φφφ • φ φ φ φ Φ φ φφφ φ φ φ φ φφφφ about 38.1 mm, the approximate distance from the top of the enamel of the upper teeth to the bottom of the enamel of the lower teeth. Each optical output unit is preferably connected to the cleaning light source by two glass or plastic fiber optic bundles that start at the distal light source, enter the device through the socket 20 and terminate in a three-part linear output window.

Non-uniformity in fiber transmission is usually observed to be minor in the absence of actual fiber breaks. The variation in optical output from point to point on the surface of each output unit or radiator should not exceed about +10%.

Whether the illumination of the stained teeth is performed individually or as a whole, the light emerging from a direct or indirect source may be continuous (on throughout the procedure), intermittently continuous (primarily on with short rest periods), pulsed (on and off in a predetermined time sequence and intensity), or a combination of continuous, intermittently continuous, and pulsed. In preferred embodiments, from about 10 to about 200 mW/cm ² (milliWatt/cm ² ) of light is applied continuously to the anterior surface of the teeth for a period of from about 10 to about 90 minutes. In a more preferred embodiment, from about 100 to about 160 mW/cm ² of light is applied continuously or continuously with short interruptions to the anterior surface of the teeth for a period of from about 10 minutes to about 30 minutes followed by an interruption or ramp-up phase of from about 1 to 10 minutes, with a cycle of · · ' ·9 · 999 9 ύ> · ♦ ·· ·

9 9 9 9 9

9 9 9 9 9 9

9 9 9 9 9

9 99 99 9 9 9 9

A. I repeated it for the entire time, approximately 40 to 60 minutes.

In one embodiment of the invention, a feedback mechanism based on reflectance can be used to control the whitening efficacy and regulate the total amount of actinic radiation applied. In all embodiments of the invention, the placement of the light source affects the density of energy applied to the teeth, as the power density decreases with distance. The preferred placement of the light source varies depending on the exact nature of the device. For the devices described above, the preferred distance for placing the device is from directly against the front surface of the teeth to about 50.8 mm on the front surface of the teeth (when measured from the center of the light source to the central tooth), the most preferred distance being about 44.5 mm.

A variety of actinic radiation sources are shown to be useful in the practice of the present invention. In general, any light source capable of emitting actinic radiation in the necessary wavelength range for activating either the inventive photosensitizer or other energy state of the dental chromogens is contemplated for use in the practice of the present invention. Light sources capable of emitting actinic radiation that is biologically safe and effective are particularly preferred, especially those sources that emit limited amounts of infrared light (700 nm and above). Infrared light penetrates tooth structure more readily and can cause excessive temperature rise in soft tissues.

tissues. Light sources (combined with filters) that emit only the wavelengths necessary to activate the inventive photosensitizer and/or to activate the tooth-colored chromophores used in the process of whitening teeth with the inventive compositions are preferred. It is generally accepted that an increase in the temperature of soft tissues of more than 5.5° C. for a significant period of time can irreversibly damage tooth structure.

More specifically, light sources that emit actinic radiation in the wavelength range of about 350 nanometers to about 700 nanometers are particularly preferred since both the photosensitizers described herein and the tooth chromogen molecules responsible for tooth coloration absorb primarily in this region of the spectrum. Light sources that emit actinic radiation in the wavelength range of about 400 to about 505 nanometers are most preferred. The uniformity of the output units should be about +/- 10% over the area of the beam once transmitted through the glass or plastic fiber to the optical output unit, which can be positioned in front of the patient's teeth. Although there are no restrictions on the input and length dimensions of such a fiber, a fiber about 10 mm in diameter and 3 m in length is preferred. Such energy may be provided by a source that generates a continuous electromagnetic spectrum filtered to a preferred wavelength with a variation of no more than about +/- 10% or by a source that generates a direct spectrum radiation or a combination of both. Suitable lamps that emit actinic radiation in the preferred wavelength range

- 290« ·· > 0« ·0 ·· « · · '0 0 · · 0 · · · 0 • 00 0 · 9 · 0 *

000 0 0 · 00 0 · 0 • 9 · 0 ♦ · · 0

000 0 0« 000 0000 09 0« include, but are not limited to, linear flash lamps, tungsten halogens, metal halides, xenon short arc lamps, mercury short arc lamps, mercury-xenon short arc lamps, argon plasma arc lamps, and argon short arc lamps. The output of two Mejiro BMH 250 Watt metal halide lamps filtered through dichroic filters to a wavelength range of approximately 400 to 505 nanometers meets these criteria.

The following examples illustrate preferred embodiments of the present invention. These embodiments are illustrative only and are not intended to and should not be construed in any way as limiting the scope of the claims of the present invention.

Example 1

In order to determine the ability of the inventive compositions to remove tooth discoloration, a preliminary in vitro study was conducted on stained bovine enamel. 4 mm squares of enamel were cut from permanent bovine incisors using a diamond cutting disc. Using a mold, the enamel squares were embedded in clear polyester casting resin (NATCOL Crafts INC., Redlands, Calif.) to provide 1.5 cm ² blocks with the labial surface exposed. The top surface of the polyester blocks was leveled to the surrounding labial surface of the enamel squares using a dental model cutter. The surface was then smoothed by hand sanding on 400 grit emery paper using water as a lubricant until all abrasion marks were removed. Finally, the top surface of the blocks was hand polished to a mirror finish using an aqueous suspension of GK1072 calcined kaolin (median particle size = 1.2 micrometers) on cotton cloth. The surface-treated samples were examined under a dissecting microscope and were discarded if they had surface imperfections.

In preparation for the formation of an artificially colored pellicle on enamel, the samples were etched for 60 seconds in 0.2 M HCl and then immersed in a saturated sodium carbonate solution for 30 seconds. A final etching was performed with 1% phytic acid for 60 seconds, after which the samples were rinsed with deionized water and connected to the staining apparatus.

The pellicle staining apparatus was designed to provide alternating immersion in the staining solution and air drying of the specimens. The apparatus consisted of an aluminum flat base supporting a Teflon rod (17.8 mm in diameter) connected to an electric motor which, by means of a speed gearbox, rotated the rod at a constant speed of 1.5 revolutions per minute. Threaded holes for screws were spaced at regular intervals along the length of the rod. The dental specimens were attached to the rod by first gluing the head of a plastic screw to the back of the specimen. The screw was then tightened inside the hole in the rod. Below the rod was a removable trough • » · 94 · ' 0 · • 9 4 4 • · • · •31 ο with a capacity of 300 ml which held the pellicle staining solution.

The pellicle staining solution was prepared by adding 1.02 grams of instant coffee, 1.02 grams of instant tea, and 0.75 grams of gastric mucus (Nutritional Biochemicals Corp., Cleveland OH 44128) to 250 ml of sterilized trypticase soy broth. Approximately 50 ml of a 24-hour Micrococcus luteus culture was also added to the staining broth. The apparatus, with the attached enamel samples and the staining solution in the trough, was then placed in an incubator at 370 ^° C with the samples continuously rotating through the staining solution and air. The staining solution was changed once every 24 hours for ten consecutive days. With each solution change, the trough and samples were rinsed and brushed with deionized water to remove any loose deposits. On the eleventh day, the staining solution was adjusted by adding 0.03 grams of FeCl3· _6H2O and this was continued with daily replacement of the solution until the staining of the pellicle film on the samples was sufficiently dark. The samples were then removed from the staining solution, brushed thoroughly with deionized water, and cooled in a humidifying chamber until further use.

Absorbance measurements were obtained over the entire visible spectrum using the CIELAB color scale (Commission International de I/Eclairage, Recommendation on a uniform color scale, differential color comparison and psychometric terms of color, Supplement 2 to CIE Publication 15 (E-13.1) 1971 (TC-1.3), 1978, Paris: Beaurea Central de la CIE, 1978). The CIELAB color scale evaluates color in terms of three axes of a spherical surface, called L, a, and b. The L value is the axis in the color surface that relates to lightness and darkness on a scale from 0 (black) to 100 (white). The a value is the axis that relates to the color from the yellow to blue scale, with the value 0 at the center of the surface, positive values are toward yellow, and negative values are toward blue. The b value is the axis that relates to the color from red to green, with the value 0 in the center of the area, positive values are towards red and negative values are towards green.

The stained glass samples were allowed to air dry at room temperature for at least one hour before absorbance measurements were made. The measurements were conducted by aligning a ^4mm2 segment of stained glass directly across the 3mm slit of a Minolta spectrophotometer. For each sample, an average of 3 absorbance readings was taken using L*a*b* factors.

The differences between pre-treatment (baseline) and post-treatment data for each color factor (L*, a*, and b*) represented the ability of the test solution to eliminate chromogens from the stained tooth.

The total change in color of the stained pellicle was calculated using the CIELAB equation

ΔΕ = [(AL*) ² + (Aa*) ² + (Ab*) ² ] ¹⁷²

The “corrected ΔE” value was calculated by eliminating from the upper preparation any positive Aa or Ab value (positive Aa and Ab values are changes in tooth color in the opposite direction from zero and therefore are intended to add color rather than remove it).

The following oxidizing composition was prepared, consisting of approximately 15% by weight hydrogen peroxide and 1% by weight of the photosensitizer precursor, 1-hydroxyethylidene-1,1-diphosphonic acid (Dequest 2010, Monsanto Corp., St. Louis, Missouri). Highly purified water (18.2 megohms, filtered through a 0.2 micron filter) was used to maintain good stability of the composition during storage. The composition was thickened with carboxypolymethylene polymer (Carbopol 974P, B.F., Goodrich Co., Cleveland, Ohio) to the density of a light, non-flowing gel. A small percentage of glycerin was added as a humectant and stabilizer (as a free radical scavenger) and the Carbopol 974P was neutralized to pH 5.00 with ammonium hydroxide, resulting in the formation of a translucent and thixotropic gel.

Component

Percent

Distilled water 49,400

1-Hydroxyethylidene-1,1-diphosphonic acid 1,000

Glycerin 99.7% 5,000

Hydrogen peroxide. 35% 42,900

Carbopol 974P 1,700

Ammonium hydroxide 29% to pH 5.5

TOTAL 100,000

The above composition was prepared in a plastic mixing chamber by combining the ingredients together, while stirring with a Teflon-coated mixing paddle until a clear solution was obtained, distilled water, 1-hydroxyethylidene-1,1-diphosphonic acid and glycerin. Carbopol 974P was slowly poured into the vortex created by the mixing paddle and mixed until a homogeneous suspension of the polymer was obtained. Finally, ammonium hydroxide was added, dropwise at a constant rate for about 5 minutes until the suspension was thickened and clear. A pH probe was periodically inserted and the addition of ammonium hydroxide continued until a pH of exactly 5.00 was reached. The resulting gel contained 15% by weight of hydrogen peroxide and was highly translucent and thixotropic (non-flowing) in nature.

Each sheet of bovine stained tooth enamel was coated with a 1 to 2 mm film of the composition from above

of Example 1 for a specified period of time and exposed to actinic radiation from one of several light sources. Table 1 below shows comparative results obtained by exposing gel-treated enamel plates to both argon plasma arc (AR) and tungsten halogen sources. This particular record for the fiber optic light guide is to be placed 5 mm from the enamel surface during light exposure. The energy of each pulse was matched to the power density measurement preceding each exposure mode and measured again after each mode to ensure consistent light source output for the duration of the test. The results are recorded

Table 1

Bovine Light Total Time Number of Tooth No. source of gel contact pulses in Table 1 below;

Energy/pulse

Corrected ΔE*

B311 none 30 minutes 0 0.00 12.76 B388 AR none 30 1.66 1.41 B277 AR 30 minutes 30 1.66 29.28 B214 AR 30 minutes 30 3.35 29.75 B283 AR 10 minutes 10 3.29 18.62 B147 AR 10 minutes 10 4.90 25.98 B401 AR 10 minutes 30 4.97 32.18 B211 AR 5 minutes 15 4.84 20.05 B213 AR 5 minutes 30 4.93 31.02 B35 TH 5 minutes 15 1.29 12.88 B35 TH 5 minutes 15 1.29 19.39 B35 TH 5 minutes 15 1.29 20.01 B35 TH 5 minutes 15 1.29 23.61

- 3o -

·· ·· · ·♦ 99 • · f • ·.9 ' 9 '9 9 9 • • 9 9 99 9 • 9 9 · · - • • • 9 9 • • · • • 9 9999 99 • ·

B35

B35

TH

TH min 5 min

1.29 25.35

1.29 26.41 * Elimination of positive

Aa and Ab calculation values

The data in Table 1 demonstrate that:

(1) In the described in vitro model, exposure of bovine enamel plates, in contact with the above inventive gel composition, to pulsed actinic radiation from an argon plasma arc light source resulted in significantly reduced tooth discoloration as compared to plates treated with either the gel alone (without exposure to the light source) or exposed to the light source only (no gel).

(2) Six consecutive treatments (over 30 minutes) of a stained bovine enamel plate (B35) with the gel and simultaneous exposure of said plate to pulsed actinic radiation from a tungsten halogen light source (5 minute exposure intervals) resulted in increased levels of tooth discoloration removed over the test period. The result was a significantly lighter color than that achieved in tooth number B311, which was also in contact with the inventive gel composition but not exposed to the light source.

Example 2

A comparative study of light transmission through various light and/or heat activated

teeth whitening gels. Spectral energy curves were developed using an Ocean Optics spectrometer with a 50 micrometer fiber for data acquisition. Light transmission was used through a glass microscope slide used as a control and test containing coated slides with a 1 to 2 mm thick layer of each teeth whitening gel and illumination by a metal halide light source connected to an 8 mm glass fiber optic light guide. The light was filtered through a 505 nm short pass filter (only wavelengths less than 505 nm passed) before entering the light guide. A spectrometric fiber optic probe was placed opposite the gel slide to detect the wavelengths of light allowed to pass through the gel to the slide. The spectral curves, in Figures 4 A to E, clearly demonstrate the degree of light attenuation caused by all commercially available compositions: Figure 4A - control; Figure 4B - Inventive Example 1; Figure 4C - Schofu HiLite; Figure 4D - Quasar Brite; Figure 4E - Opalescence Xtra.

The power density attenuation, measured in mW/cm ² , was determined for the same four compositions by again placing a 1 to 2 mm layer of each gel or paste on a glass microscope slide and placing the slide/gel assembly in the path between the light source and the detector well of the power density meter. Due to the depth and shape of the detector well, the plate was 7 mm above the actual detector surface, rather than directly in contact with it. The power density was recorded

9

9

4

4

9 9 9

9

9999 99 . 44

- 9f 9 9

9 9 at the beginning (B) and at the end of the 60-minute light exposure (E). The power density without a plate or gel in the light path was set to 175 mW/cm ² . The results are shown in Table 2 below.

Table 2

Composition US Patent No. Energy Density (mW/cm ² )

Control (plate only) Example I (B)+(E) 032 178 165 160 25 & So Shofu Hi-Lite (B) 5 So Shofu Hi-Lite (E) 5 032 178 50 Quasar Brite (B) 5 240 415 110 Quasar Brite (E) 5 249 415 111 Cpalescenoe Xtra (B) 5 785 527 65 Cpalescenoe Xtra (E) 5 785 527 94

Example 3

Another clear hydrogen peroxide gel was prepared having a lower concentration of oxidant (3% by weight H2O2) but at a pH of 7.0 and a much higher viscosity (approximately 1,000,000 mPa.s). The gel below was prepared according to the procedure in Example 1 except that a Kynar coated Ross Double Planetary mixer (Charles Ross & Sons, Hauppauge, New York) was used to handle the increased viscosity achieved during and after the ammonium hydroxide neutralization. Sodium stannate was added as an additional stabilizer for the hydrogen peroxide.

·· ·· ·· • · · · · <

• · · · 4 . · ' ' · · · · I • · · · 4 ····· ·· · · ·· ·· • · · ·

Component

Percent

Distilled water 81,010

Glycerin 99.7% 5,000

1-Hydroxyethylidene-1,1-diphosphonic acid 0.400

Sodium stannate 0.015

Hydrogen peroxide 35% 8.570

Carbopol 974P 5,000

Ammonium hydroxide 29% to pH 7.0

TOTAL

100,000

The ability of 3% hydrogen peroxide gel to be transparent to visible light in the wavelength range of 380 to 700 nanometers is indicated in Table 3 below.

Table 3

Higher tooth No. Oxidizing gel Time period zSj ^vtae<sil! y (nancmeters) Pulses/ time Hsteta sLly (nW/cn?) Bheps/ pis (JuL) ΔE * B388 Example 2 5 minutes AR 380-505 15 4.84 19, 67 B388 Example 2 5 minutes AR 380-505 15 4.84 29.43 B388 Example 2 5 minutes AR 380-505 15 4.84 32.74 B365 Example 2 5 minutes none - 0 0 3.41 B365 Example 2 5 minutes none - 0 0 4.23

- 40·· 9· ' ♦ · · » • · · • «·· · • · 9··· ·· ·» l · · <

> · · I » · · 4 ·· *·

B365 Example 2 b min none - B365 Example 2 b min AR 380-bOb B365 Example 2 5 minutes AR 380-505 B367 Example 1 30 minutes TH 400-520

0 0 5.78 15 4.84 23, 49 15 4.84 30.27 scLKáslá 250 32.26

* Elimination of positive Aa and Ab values from the calculation.

Example 4

Extracted human teeth (HE) that were unstained and free of amalgam or resin-based restorative materials were used to study the ability of the inventive compositions to eliminate discoloration of human enamel and dentin. The teeth were covered with a 1 to 2 mm thick layer of oxidizing gel and irradiated according to the regimens shown in Table 4 below. The resulting change in tooth color (A shades) was recorded as the number of VITA® shade differences between the original baseline VITA® shade value and the final VITA® shade value.

Table 4

Tooth No. Gal. light eater Time of exposure minutes (min) Jelly/ pitsy Shade (claw.) Shade (dance) A/ Shades HE2 Example 1 AR 30 1 4.84 B4 C2 6 HE3 Example 1 AR 30 1 4.84 A4 A3,b 3 HE4 Example 1 AR 30 1 4.84 A3 B2 6 HE5 Example AR 30 1 4.84 B3 D4 3 HE6 Example 1 AR 30 1 4.84 th3 B2 8

- 41 ·,Φ , .99. Φ Ο • Φ Φ Φ • · Φ · • Φ Φ Φ » « · » ·

HE7 Example 1 AR 30 1 4.84 A3 Al 7 HE8 Example 1 AR 30 1 4.84 A3.5 A2 7 HE9 Example 1 AR 30 1 4.84 A3 Al 7 HE10 Example 1 AR 30 1 4.84 A4 A3.5 6 HEU Example 1 AR 30 1 4.84 A3, 5 A2 7 HE12 Example 1 AR 30 2 4.84 A3.5 A2 7 HE13 Example AR 30 2 4.84 B3 B2 8 HE14 Example 1 AR 30 2 4.84 A3.5 B2 9 HE15 Example 1 AR 30 2 4.84 A4 Al 13 HE16 Example 1 AR 30 2 4.84 B4 B1 12 HE17 Example 1 AR 30 1 1.64 A3 A2 4 HE18 Example 1 AR 30 1 1.64 B4 B2 10 HEL9 Example 1 AR 30 1 1.64 C4 D3 6 HE20 Example 1 AR 30 1 1.64 B3 A2 6 HE21. Example 1 AR 30 1 1.64 B3 B2 8 HE22 Example 1 none 30 0 0 B3 A2 2 HE23 Example 1 none 30 0 0 A3 A2 4 HE24 Example none 30 0 0 B3 D4 3 HE25 Example 1 none 30 0 0 D3 B2 7 HE26 Example 1 none 30 0 0 B3 A2 6 HE27 Example 1 Tungsten halogen 60 permanent 250 rtW/cn? B2 Al 9

Example V

Extracted human teeth are bleached by applying up to 2 mm thick gel films to the enamel surface and exposing the same surface to varying power densities from a metal halide light source with a 505 nm short-pass inner filter. Comparisons were made between two controls, one with gel exposure only (no light) and one with light exposure only (no gel). The exposure regimens, consisting of gel application (except for the light/no gel case), followed by 20 minutes of continuous light exposure, were repeated three times (3 x 20 minutes).

Table 5

2±> No. Gal Light Source Density of force (Gtffiř/crf) , Eiltr Duration of the test Ebbeginning shade RrEChrrý cristín Changing the shade HE 101 Example 1 MH 250 505 3 x 20 minutes A3.5 Al 7 IE 102 Treasure 1 MH 250 505 3 x20min B4 A2 8 IE 103 Example 1 MH 175 505 3 x 20 minutes A3 B1+ 8 IE 104 Example 1 MH 175 505 3 x 20 minutes A4 B2 12 HE 105 Example 1 MH 175 505 3x20 minutes B3 B2 8 HE 106 Example 1 MH 175 505 3 x 20 minutes A3 Bit 8 HE 107 Example 1 MH 175 505 3 x 20 minutes A4 A2 10 HE 108 Example 1 none 3 x 20 minutes A3.5 A3 3 HE 109 Example 1 none 3 x 20 minutes A4 D3 5 HE 110 Example 1 none 3 x 20 minutes A3, 5 A3.5 0 HE 111 Example none 3 x 20 minutes A4 A3 6 HE 112 Example 1 none 3 x 20 minutes A4 A3.5 3 HE 113 shit MH 175 505 3 x 20 minutes A3 A3 0 HE 114 none MH 175 505 3 x 20 minutes A4 A4 0

9* *· Β-'·-· · »· '·'· 99 • · · · ' '99 9 9 - t> * « : · • · Β · - · 9 9 » • BBB O B »B · · β « • B · » 4·»« ···· ·· »·» 9999 99 ··

HE 115 shit MH 175 505 3 x 20 minutes A3, 5 A3 3 HE 116 none MH 175 505 3 x 20 minutes. B3 B3 0

Example 6 Dřeňová by informing The endo-tooth chamber in cooperation with the patient was strengthened using thermal

probes and thermally conductive ceramic pastes. Pulp temperatures were measured during a simultaneous bleaching procedure in which illumination was provided using a simultaneously available Union Broach illuminator and the device described in the immediate application used at the most preferred wavelengths of 400 to 505 nanometers. Measurements of the power densities at the tooth surface showed comparable power densities for each device (230 mW/cm ² for the Union Broach illuminator and 200 milliwatts/cm ² for the device described in this application). The results are shown in Table 6 below.

Illumination using the device described in this application at preferred wavelengths of about 400 to 505 nanometers increased the temperature of the pulp chamber less than the Union Broach illuminator. In this experiment, temperatures rose to a maximum within 20 minutes and then stabilized. In contrast to the temperature rise seen with the Union Broach illuminator, at no time did the temperature rise above 5.5°C occur with the device in the present application, which could lead to thermally induced pulpitis if it were • 0

- 440 0 • 00 maintained for a significant period of time. The temperature changes recorded could probably be greater than those recorded by living teeth, as endo-teeth

they have no cooling. blood supplied to allow for additional Temperature rise (°C from room temperature) Time (min) Union Broach Brite Smile 2000 5 4 '2.9 10 8 4.5 15 9 5.3 20 9 4.2 25 9.5 4.5 30 - 9 4.3

Upon reading the present application, various alternative constructions and embodiments will become apparent to those skilled in the art. Such variations are contemplated within the scope and spirit of the present invention. The present invention is limited only by the claims that follow and their equivalents.

Claims (32)

PATENTOVÉ Claims Claims 1. A tooth whitening composition comprising a translucent first component which is a carrier compound; and a translucent second component which is an oxidizing compound which, when applied to a colored tooth and exposed to actinic radiation, is activated to aid in tooth whitening. Teeth whitening composition according to claim 1. characterized in that it further comprises a third component which is a photoactive substance which, when exposed to actinic radiation, extends the activation of the second component to facilitate tooth whitening. by The composition of claim 1, wherein the first component is a carboxypolymethylene gel The composition of claim 1, wherein the second component comprises either a peroxyacid. characterized by peroxide or The composition of claim 4, wherein the peroxide is selected from the group consisting of hydrogen peroxide, carbamide peroxide, alkali metal peroxide, alkali metal percarbonate, and alkali metal perborate. • 8 · «-» 9 9 - 46ί. 9 «9 9 9 999 • 9 • 9 · 9 4 5 9 «» • 9 9 9 • 9 9 9 9 9 β. Composition according to claim 4, characterized in that:. the peroxyacid precursor is selected from the group consisting of glyceral triacetate, acetylated amino acids, acetylsalicylic acid, and tetraacetylethyldiamine. The composition of claim 1, wherein the first and second components transmit about 70% of the applied energy upon exposure to light. The composition of claim 1, wherein the first and second components do not absorb substantially light in a wavelength range of from about 350 nanometers to about 700 nanometers. The composition of claim 8, wherein the first and second components do not absorb substantially light in a wavelength range from about 380 nanometers to about 500 nanometers. The composition of claim 2, wherein the photoactive component absorbs light in a wavelength range from about 350 nanometers to about 700 nanometers and converts this energy into thermal or chemical energy. The composition of claim 10, wherein the photoactive component absorbs light in a wavelength range from about 380 nanometers to about 500 nanometers. • · Composition according to claim 2, characterized in that the photoactive component is of molecular size, pH and surface charge which allows more efficient penetration into the enamel and dentine structure. The composition of claim 2, wherein the photoactive component is selected from the group consisting of semiconductor particles, benzophenone derivatives, benzotrazole derivatives, diketones, metal ligand complexes, and phthalocyancin metal complexes. The composition of claim 13, wherein the semiconductor particles are titanium or zinc oxides of nanometer size. 15. A method of light-activated tooth whitening comprising the steps of: applying a tooth whitening composition comprising a translucent carrier compound and a translucent oxidizing compound which upon contact with the surface of the colored teeth and exposure to actinic radiation is activated to aid in the tooth whitening of one or more teeth; and < exposing the composition to actin light to activate said oxidizing compound. 48Φ φφφφ φ Φ φφφφ φ φ · * 'Φ Φ ·. ΦΦΦΦ »» »» »» »» »» * * * * φ φ φ · · · · · · 16. A method of light-activated tooth whitening comprising the steps of: administering a photosensitive agent that absorbs actinic radiation upon contact with the tooth surface of one or more teeth; applying a tooth whitening composition comprising a translucent carrier compound and a translucent oxidizing compound capable of facilitating dental whitening by the aforesaid photosensitive agent; and exposing said photosensitive agent and teeth whitening composition to actinic radiation to activate said oxidizing compound. 17. The method of claim 15, wherein the light source emits light in the range of about 350 nanometers to about 700 nanometers. The method of claim 17, wherein the light source emits light in the range of about 380 nanometers to about 500 nanometers. 19. The method of claim 16, wherein said photosensitive agent absorbs light in a wavelength range from about 350 nanometers to about 700 nanometers and converts this energy into thermal or chemical energy. • · · ^{1 1 1 1 1 1 1} r r r r r r - 4y - - - - - - - - - - - - - - - - - - - - - - - - - The method of claim 19, wherein the photosensitive agent absorbs light in a wavelength range from about 380 nanometers to about 500 nanometers. 21. The method of claim 16, wherein the photosensitive agent is a molecular size, pH, and surface charge that allows effective penetration into the enamel and dentine structure. The method of claim 16, wherein the photosensitive agent is selected from the group consisting of nanometer-sized semiconductor particles, benzophenone derivatives, benzotrazole derivatives, diketones, metal ligand complexes, and phthalocyancin metal complexes. The method of claim 16, wherein the light source emits light in the range of about 350 nanometers to about 700 nanometers. The method of claim 23, wherein the light source emits light in the range of about 380 nanometers to about 500 nanometers. 25. A tooth whitening device comprising: light source; at least one optical output unit; - projection means for holding and positioning the optical source outside the patient's mouth in a manner that provides approximately simultaneous and uniform illumination of the patient's anterior teeth by the optical output unit; and coupling means for connecting the light source to the optical output unit. 26. The tooth whitening device of claim 25 having three optical output units. 27. A tooth whitening device according to claim 25 having six optical output units. 28. The tooth whitening device of claim 25, wherein the projection means has an approximately convex shape. , 29. The tooth whitening device of claim 25, wherein said means for connecting the light source to the optical output unit is at least one fiber optic beam. 30. The tooth whitening device of claim 25, wherein said means for connecting the light source to said optical output unit is at least a double-fiber optic beam. «9 9 9 9 9 9 9 9 31. The tooth whitening device of claim 29, wherein the fiber optic beam is of glass or plastic. 32. The tooth whitening device of claim 25, wherein said optical output unit is a shape selected from the group consisting of a circular, triangular, and straight shape. 33. The tooth whitening device of claim 25, wherein the optical output unit is linear in shape. 34. A method for whitening teeth comprising the steps of: applying a teeth whitening composition to the patient's teeth; and exposing said composition to light emitted from the device of claim 25.