AT504152A1 - TOOTHPASTE AND USE OF SUCH A TOOTHPASTE - Google Patents

Description

Toothpaste and use of such a toothpaste

The present invention relates to a toothpaste containing at least one ingredient selected from the group consisting of abrasive, humectant, swelling agent, foam blowing agent, flavoring agent, sweetener, preservative and fluoride.

Because of different dietary habits (e.g., tea or coffee consumption), tobacco consumption, or, in part, as a result of disease, surgery, dental inflammation or root tip resection, discolouration of teeth may occur. Such discolorations, which usually occur on the enamel and the dentin, are disturbing for the person concerned, which is why in recent years, numerous methods for bleaching or whitening of teeth have been established in which acts on the tooth surface, a bleaching agent, in particular by redox reactions with the substances causing the discoloration brightens the tooth again. Frequently, such processes employ substances which release radicals or, for example, atomic oxygen, such as e.g. Peroxides. According to the known state of the art, a distinction is currently made between so-called home-bleaching (home-use method) and so-called in-office bleaching (performed in the doctor's office). The home-bleaching process uses weak or stronger peroxide compounds, in which the reactive oxygen or radicals are chemically driven off. Due to the chemical process, which takes place without the action of light, the enamel surface is relatively strongly attacked due to the long bleaching time of up to several hours. Such processes are also referred to as chemical bleaching. When so-called dental in-office whitening, which is performed only by dentists or dentists, the expulsion of active oxygen or radicals from the actual bleaching agent (usually strong peroxide compounds) takes place by chemical or chemical and photothermal path through the use of lamps , Since normal per-office bleaching procedures use strong peroxide compounds, the bleaching time can be shortened. Nevertheless, one can observe that the enamel is attacked by the chemicals. Additional thermal support by lamps is called photothermal bleaching. By additionally warming the bleach, which is often applied as a gel, the strong peroxide compounds are degraded more rapidly, which additionally shortens the duration of the bleaching process. Although the shortened • · · · ···············································································

Bleaching period is generally positive for the enamel, but you can still occasionally observe damage to the enamel. Lamp systems are usually used with high radiation power: e.g. Halogen lamps with 380 to 500 nanometers after filtering with an intensity of 400 to 1000 mW / cm2 or plasma arc lamps (argon, xenon) with wavelengths of 430 to 505 nanometers after filtering and an intensity of 1600 to 2000 mW / cm2. Laser bleaching processes, which are also classed as photothermal bleaching processes, use lasers with output powers of approximately 1 watt, which in comparison to a conventional 75 watt incandescent bulb causes a 100-fold increase in incident intensity. For this reason, the treatment times in laser bleaching process are about 30 to 60 sec. And a subsequent exposure time of a few minutes. In comparison to conventional chemical processes, damage to enamel is significantly reduced in photothermal processes. The disadvantage, however, that the cost of a laser are very high. In addition, the bleaching material must be precisely tuned to the laser, e.g. the absorption coefficient of the bleaching agent in conjunction with the peroxidic component, so that there is no thermal overload of the tooth, in particular the pulp.

The present invention is based on the object to provide an improved toothpaste of the type mentioned, which avoids the disadvantages of the prior art and further develops the latter in an advantageous manner. In particular, a toothpaste which nourishes and cleans the teeth is to be created, which optionally simultaneously permits efficient tooth whitening without damage to the enamel and the gums.

According to the invention this object is achieved by a toothpaste according to claim 1. Preferred embodiments of the invention are the subject of the dependent claims. The toothpaste according to the invention can be used in particular for bleaching the teeth.

It is therefore proposed according to the invention to add to the toothpaste a bleaching agent containing a photocatalyst. In this way, the bleaching agent contained in the toothpaste can be activated by irradiation with light of suitable wavelength and intensity in order to whiten the teeth and lighten unwanted discolorations. Optionally, the toothpaste may also be conventionally used only to clean and care for the teeth by using them without light irradiation. The user has the option, so to speak, whether he wants to clean the teeth with the toothpaste, or whether he wants to activate the contained bleach by applying light to achieve a cosmetic bleaching of the teeth. The bleaching agent contained is thus photoreactive and / or photocatalyzed.

It is particularly advantageous that the bleaching agent used contains at least one photocatalyst, which in this way the light activation of the bleaching agent in a very short time and especially during rubbing on the teeth, so to speak while brushing teeth can be done.

It has proven particularly favorable if the photocatalyst is designed as a nanoparticle. Nanoparticles have the advantage that they have a large surface area and thus have favorable catalytic properties. In addition, they are available in large quantities and because of their small size, they have no negative mechanical properties for the tooth. Nanoparticles are particles with a diameter of about 1 nanometer to several hundred nanometers.

It is preferably provided that the photocatalyst is a semiconductor, in which case it has turned out to be advantageous if the nanoparticles or semiconductors from the group T1O2, ZnO, Si, σ-Sn come.

In a preferred embodiment, it is provided that the nanoparticles are anatase. Anatase is titanium dioxide with a tetragonal one

Grid, which has particularly favorable properties for the production of active oxygen.

It is further provided that the nanoparticles have a diameter of not more than 100 nanometers. Due to the tooth structure, nanoparticles with a diameter of about 100 nanometers have proven to be particularly accessible and have proven to be ideal photocatalysts for releasing active oxygen or reactive radicals.

It is further provided that the free-radical initiator is preferably hydrogen peroxide and / or a Peroxydabspalter, it is advantageous if in the bleaching agent, the hydrogen peroxide in the form of an aqueous solution in a concentration of 0.10 to 10%, preferably of about 5%.

Although the bleaching agent already has excellent properties, it is still favorable if, in addition, a thickening agent is present, it being especially provided that the thickening agent is of a polyacrylate type. The presence of a thickening agent makes it possible to form the bleaching agent as a gel or paste which is applied to the tooth. Conveniently, the, for example, peroxidic substance can settle in the matrix of the gel and be ideally released there due to the photocatalytic reaction.

Due to the strong oxidative reaction of hydrogen peroxide, it has proven to be advantageous if an alkaline component or a buffer substance to increase the pH is present, it is recommended that the alkaline component or buffer substance Na2C03, since sodium carbonate on the one hand only slightly alkaline is and has excellent buffering properties and, moreover, is tasteless.

Peroxides have a strong tendency to decompose under great heat: e.g. 2H2O2 - > 2H20 + 02 + 196.2 kJ. At room temperature, however, the rate of decay is extremely low. One speaks of a practical resistance or a metastable state. When heated to higher temperatures, the peroxide decomposes rapidly, possibly explosively. The large decay inhibition of H2O2 is based on the fact that the first step of the thermolysis consists in an energy-consuming molecular cleavage into 2HO radicals (HOOH + 211 kJ -> 2HO). These then continue to react with hydrogen peroxide (HO + H2O2 -> H2O + HO2; H02 + H2O2 -> H20 + 02 + HO) to initiate a radical chain reaction. By suitable catalysts, the decomposition rate of hydrogen peroxide can be greatly increased, so that may occur at room temperature stormy oxygen evolution and highly concentrated solutions because of the strong caused by the H202 thermolysis temperature increases even explosive decay. The characteristic property of H2O2 is in particular its oxidizing effect: H202 - > H2O + O or H202 + 2H + + 2e * - > 2H2O. The normal potentials for H2O2 in acid solution are + 1.76 volts, in alkaline solution + 0.87 volts. Therefore, it is favorable that the bleaching material during the application is in the alkaline range and therefore causes only a small chemical attack. In addition, the H202 in the gel in the specific case greatly diluted (about 5%), whereby a chemical attack is excluded even after very long treatment time (over 1 hour) according to previous studies.

Less pronounced is the reducing effect of Η2θ2: H2O2 - + 2H + 02 or H202 - > 2H + + 02 + 2e \ The normal potentials for H202 in acid solution are +0.68 volts and in alkaline solution -0.07 volts. The reducing effect thus occurs only against pronounced oxidizing agents. The whitening of teeth is primarily due to the atomic oxygen produced by the decay of H202. The normal potentials for atomic oxygen in acidic solutions are 2.42 volts, in basic solutions 1.59 volts. In the case of a bleaching agent according to the invention, when working in the basic range there is a low value of the normal potential for H 2 O 2 and a high value of the normal potential for oxygen. Thus, a low portion of the che- •············································ However, a high rate of oxidation for the destruction of the attachment or intercalation of the tooth is to be expected.

It is further provided that the nanoparticles based on the bleaching agent in a content (mass / mass) of about 1 to 90%, preferably in a content of 60 to 80%. More preferably, the mass fraction is about 75%. It has been found that with such high concentrations of nanoparticles, the oxygen delivery can be faster and thus the duration of treatment can be shortened.

When using a thickener it is provided that the thickener is present in a content of 10 to 20%, preferably about 17%. This is a cheap amount to make an ideal gel.

It is further provided that the alkaline component is present in a content of less than 10%.

The toothpaste can basically be in different forms. According to one embodiment of the invention, the toothpaste may be in the form of a cream or teeth whitening. Alternatively, the toothpaste may be formed in the form of a transparent or translucent gel.

In addition to the bleaching agent described above, the toothpaste contains other known dental care, cleaning and active ingredients, in particular abrasives, humectants, swelling agents, foam blowing agents, flavorings, sweeteners, preservatives, antibacterial substances and / or fluoride. Suitable abrasives are various substances. According to an embodiment of the invention, the toothpaste may contain silica and / or pumice. The humectant may be glycerol and / or sorbitol. In particular, polymeric thickeners may be provided as swelling agents, as surfactants, especially anionic surfactants, foam blowing agents may be used. ········· ····································· · ········ · ··· -8- be added. Flavors may be included in the form of oils such as peppermint, spearmint or cinnamon oils, it being understood that other flavors may be added depending on the desired flavor.

The levels of bleaching agent in the toothpaste can basically be chosen differently, depending on the intensity with which bleaching of the teeth is to be achieved. According to a preferred embodiment of the invention, the proportion by weight of the bleaching agent relative to the total weight of the toothpaste is between 0.04% and 5.0%. In particular, the weight fraction of bleach may be about 1.0%. Within this proportion of bleach, the nanoparticle content in the aforementioned manner may be about 60 to 80% by mass, based on the anhydrous bleach, preferably about 75% by mass.

Instead of the prior art in a two-stage process on the one hand with conventional toothpaste to brush the teeth, and then apply a bleaching agent, for example, with a spatula and then put a bulky lighting head on the teeth to activate the bleach, can with the proposed toothpaste when rubbing the toothpaste on the teeth at the same time the bleaching of the teeth are set in motion by the included bleach is activated by exposure to light. Advantageously, the bleaching agent is triturated on the teeth with a boron-field and / or sponge-like soft structure and activated during the rubbing by light of suitable wavelength and intensity emitted by the soft structure. For this purpose, a toothbrush-like bleaching apparatus may be used, the working head on the one hand has a soft structure in particular in the form of a bristle field, possibly also in the form of a bulge-like sponge or tile structure and on the other hand has a lighting device by means of which the bleach activating the light are radiated to the bleach on the soft structure can. The soft structure is suitable for producing a sufficient... · · · · · -9-

To pick up amount of preferably pasty or gel-like bleach and applied as in the normal brushing teeth by reciprocating the soft structure on the teeth and to rub on these. Advantageously, the pressure-compliant soft structure is flexurally and compressively elastic to gently rub the bleach and to prevent irritation of the gums or even damage to the gums and the tooth surfaces. The bleaching agent is simultaneously activated by the lighting device integrated in the working head or the soft structure and the light emitted by it.

In this case, the light causing the activation of the bleaching agent can be passed at least partially through the soft structure and radiated from the soft structure, in particular at its working surface. When forming the soft structure in the form of a bristle field, the light can be passed through the bristles and radiated at the bristle ends.

According to a preferred embodiment of the invention, the toothpaste is used under irradiation with light in a wavelength range of 450 to 480 nanometers, preferably about 460 nanometers. In this wavelength range occurs a cooling of the irradiated material.

In particular, when using a semiconductor, light having a wavelength corresponding to the bandgap of the semiconductor may be used. As an alternative to the aforementioned LEDs, the light source may also be an argon laser, a KTP laser, a diode laser or a Nd-Yag laser or a CO2 laser.

In a preferred embodiment, it is provided that anatase particles are irradiated with light of a wavelength in the UV-near range, preferably at a wavelength of 380 to 500 nanometers, more preferably at a wavelength of about 460 to 470 nanometers. Thermal damage to the pulp can not occur if the power of the power supply is exceeded. •. The toothpaste used for the catalytic bleaching is not changed in such irradiation. The present in bleach nanoparticles with semiconductor properties act as catalysts that serve to generate active oxygen when irradiated. The wavelength of the radiation is determined from the energy gap of the semiconductor and depends on how much energy has to be expended to excite an electron from the non-conductive band of the semiconductor into the conductive band of the semiconductor. The energy consumed must be higher than this bandgap energy. When using anatase nanoparticles, it has e.g. pointed out that the best wavelength at 380 to 500 nanometers is preferably 450 to 480 nanometers, which can be produced with light emitting diodes (LED) on the market. The performance of these LEDs are in the milliwatt range and are sufficient to produce the required for the bleaching active oxygen. In addition to LEDs with different wavelengths between 320 and 500 nanometers, a conventional curing lamp for so-called composites was used in the investigations carried out. The bleaching results are comparable, i. Conventional curing lamps can also be used for the process according to the invention. In addition, the following semiconductors or their nanoparticles are available for the use of the method according to the invention:

Zinc oxide (band gap 3.2 eV) with an excitation wavelength of about 387 nanometers.

Silicon (bandgap energy 1.1 eV) corresponding to an excitation wavelength of 1127 nanometers. σ-tin (with a band gap energy of about 0.08 eV) corresponding to an excitation wavelength of about 15 // m. ··· ♦ 0t 0 ····································································································································································································

In bleaching, the laser radiation used must be energetically higher than the bandgap energy of the nanoparticles, i. the gel is excited at a lower wavelength than the bandgap energy. For example, conventional lasers could also be used for the above nanoparticles. There are e.g. Argon lasers (488 to 514 nanometers), KTP lasers (532 nanometers), diode lasers (805 nanometers), and Nd-Yag lasers (1064 nanometers). With a CO2 laser (10600 nm) an a-tin nanoparticle could be excited.

The invention will be explained in more detail with reference to a preferred embodiment and associated drawings. In the drawing shows:

1 is a schematic flow chart for explaining the operation of the bleaching agent provided with a photocatalyst and its reaction to light irradiation;

The process shown in Fig. 1 is intended to illustrate the reaction mechanism and the catalytic cycle required for bleaching. In a first step, light in the UV-near region strikes, for example, an anatase particle. Due to the semiconductor property and the excitation by the light, an electron is excited from the non-conducting band into the conducting band. The formation of an electron in the conduction band and a hole in the nonconducting band occurs. Both the electron and the electron gap migrate to the surface. There may be a transfer of the electron to atmospheric oxygen and the formation of a Superoxidradikals or the electron gap accepts an electron of a hydroxyl ion in aqueous solution. The hydroxyl ions are present in sufficient amount due to the autoprotolysis of water or the basic component. Subsequently, this hydroxyl radical catalyses H 2 O 2 decomposition. Now, if a basic component is present, the left side of the figure, so the formation of the hydroxyl radical is favored. The reaction with the superoxide radical O 2 is of secondary importance. If the nanoparticles are too large, they will occur within the 00 ♦ · · * ·· · 0000 0 00 00 00 00 · • · · · · · · 0 0 0 · • ·· * * · · · ···· 0Φ000 0 0 0 0 0 - 12-

Particles to recombine the electrons and electron hole or gap pairs and thus the generation of radicals in the solution is suppressed. Therefore, larger particles, e.g. when using conventionally purchased finely powdered titanium dioxide, no bleaching effect. The lifetime of radicals in basic solution is also higher than in an acidic environment. Therefore, the light basic environment is more preferable. Titanium dioxide nanoparticles are semiconductors having a bandgap energy of about 3 eV, which corresponds to an excitation wavelength of about 400 nanometers.

As already described, small particles can already cause the decomposition and the thermal excitation of a decomposition of the H2O2.This disintegration can not be controlled technically in a simple way.Apart from the chemical attack on tooth and enamel of the teeth, the application of the gel would already occur before the application of the gel In the case of an application according to the invention with 5% H 2 O 2 and an anatase nanoparticle, no decomposition is observed under normal conditions, whereas if the gel is irradiated with UV-near light, the decay begins after a few Seconds, ie the quantitative decay can be controlled by the appropriate control of the light supply or the light output and light energy.A control is on the one hand by optimizing the wavelength and the percentage of nanoparticles possible.Typically, nanoparticles of the type according to the invention (eg anatase) e specific surface area of 70 to 120 m2 / g. The process runs completely without heating and therefore there are no thermal damage to the tooth or gums.

The activation of the bleaching agent can advantageously take place by means of a bleaching device designed as a possibly electric toothbrush, the working head of which carries a bristle field which comprises a multiplicity of bristle tufts. In this case, a lighting device can be integrated into the working head, with the aid of which the bristle field and the thus to be written on the teeth can be written on the teeth.

Toothpaste containing the vorgenante bleaching agent is irradiated with activating light.

Advantageously, the toothpaste can be used on the one hand for the cosmetic bleaching of teeth, on the other hand, the toothpaste can also be used for deactivation or killing of bacteria, fungi and / or viruses, for example to treat athlete's foot, herpes or the like. Surprisingly, the nanoparticles are also extremely effective in controlling such germs.

Claims (25)

Toothpaste and use of such a toothpaste Claims 1. Toothpaste containing at least one ingredient selected from the group consisting of abrasive, humectant, swelling agent, foam blowing agent, flavoring agent, sweetener, preservative and fluoride, characterized by a bleaching agent comprising at least one photocatalyst. ········· * •····················································································· 2. Toothpaste according to one of the preceding claims, wherein the bleaching agent contains a radical or, in particular atomic, oxygen-releasing substance. 3. Toothpaste according to one of the preceding claims, wherein the photocatalyst is formed as a nanoparticle. 4. Toothpaste according to one of the preceding claims, wherein the photocatalyst is a semiconductor. 5. Toothpaste according to one of the two preceding claims, wherein nanoparticles from the group TiO 2, ZnO 2, Si or σ-Sn are used. 6. Toothpaste according to claim 3 or one of the dependent claims, wherein the nanoparticles are formed as anatase. The toothpaste of claim 3 or any claim dependent thereon, wherein the nanoparticles have a diameter of not more than 100 nanometers. 8. toothpaste according to any one of the preceding claims, wherein the bleaching agent contains as a free radical generator hydrogen peroxide and / or Peroxydabspalter. Toothpaste according to the preceding claim, wherein the hydrogen peroxide and / or Peroxydabspalter in a content of 0.04% to 5.0%, preferably 1% is present. A toothpaste according to any one of the preceding claims wherein the bleaching agent contains a thickener or gelling agent. ······ «I ····· ············································· * ·· · ··· -3- A toothpaste according to the preceding claim, wherein the thickening agent is preferably a polyacrylate type. 12. Toothpaste according to one of the preceding claims, wherein the bleaching agent contains an alkaline component or a buffer substance to increase the pH. Toothpaste according to the preceding claim, wherein the alkaline component or buffer substance is sodium carbonate (Na2CC> 3). 14. Toothpaste according to one of the preceding claims, wherein the weight fraction of the bleaching agent based on the total weight between 0.04% and 5.0%, preferably about 1%. 15. Toothpaste according to claim 3 or one of the dependent claims, wherein the weight fraction of the nanoparticles based on the weight of the bleaching agent is between 1% and 90%, preferably 50%. 16. toothpaste according to any one of the preceding claims, wherein as the abrasive silica, calcium carbonate, sodium bicarbonate, polyphosphates, polyethylene, pumice and / or the like is provided or the combinations of several abrasives. 17. Toothpaste according to one of the preceding claims, wherein surfactants are contained as foam blowing agent. 18. Toothpaste according to one of the preceding claims, wherein as flavoring oils of peppermint, spearmint and / or cinnamon are included. 19. Toothpaste according to one of the preceding claims, wherein as an additional ingredient an antibacterial substance is included. ······························································································ 20. Toothpaste according to one of the preceding claims, wherein it is formed as a cream. 21. Toothpaste according to one of claims 1 to 20, wherein it is formed as a gel. 22. Use of a toothpaste according to one of the preceding claims for bleaching of teeth. 23. Use of a toothpaste according to the preceding claim, wherein the bleaching agent is activated during and / or after the application to the teeth by irradiation with light. 24. Use of a toothpaste according to the preceding claim, wherein the toothpaste is triturated with a bristle field and / or sponge-like soft structure, in particular with a toothbrush head, on the teeth and during the rubbing by the light which is emitted to and / or from the soft structure , is activated. 25. Use of a toothpaste according to one of claims 1 to 21 for the treatment of bacterial, fungal and / or viral diseases. Aug. 17, 2006