RU2697401C1 - Method of teeth enamel bleaching - Google Patents

Abstract

FIELD: cosmetology; medicine.

SUBSTANCE: invention refers to dentistry and cosmetology. Disclosed method of teeth enamel bleaching involves pre-treatment of teeth with an activating composition containing catalysts and having pH 8–9, followed by application on tooth surface of bleaching composition containing peroxide whitening agent in concentration equivalent to 0.1–6.0 % hydrogen peroxide, and irradiating the bleached tooth surface with blue light at wave length 400–450 nm for 10–30 minutes. Activating composition contains sodium molybdate and sodium tungstate as catalysts, with the following content of components, wt%: sodium molybdate 0.1–1.0; sodium tungstate 0.1–1.0; surfactant 1.0–3.0; water – balance.

EFFECT: method provides high effectiveness of teeth whitening with low concentration of hydrogen peroxide, which contributes to reducing side effects of teeth whitening, and also reduces damage or irritation of gums and mucous membranes of the oral cavity.

6 cl, 3 tbl, 3 ex

Description

The invention relates to the field of dentistry and cosmetology and can be used for whitening tooth enamel.

Human teeth have an inner soft layer called dentin and an outer hard layer called enamel, which protects the inner structure. Under typical conditions, the enamel surface is coated with a thin layer of salivary proteins called plaque. Enamel or plaque, or both, can be stained and present on the outside of the teeth as an undesirable phenomenon. In addition, the enamel layer of the teeth is largely composed of hydroxyapatite mineral crystals, which create a porous surface structure. The porous nature of enamel allows coloring components and decolorizing substances to penetrate the structure of the teeth, staining them. Behavioral and environmental factors that contribute to tooth staining include regular consumption of coffee, tea, cola or tobacco products, as well as the use of oral stain-promoting products such as chlorhexidine.

Teeth whitening is currently a highly demanded service and is usually performed by dentists in a clinic setting. In this case, gels with a high content of hydrogen peroxide (up to 35%) are used, which requires isolation of soft tissues and often side effects such as hypersensitivity after the procedure occur, if the technology is not followed, severe burns of the mucous membranes of the mouth are possible.

Known tools for home teeth whitening, which are divided into gels with different concentrations of hydrogen peroxide (from 0.1 to 6%) and strips in which the whitening composition is applied to the polymer substrate. All home remedies are used in the course of 5-10 days in a row, which can be quite inconvenient. In this case, after a whitening course, increased sensitivity of tooth enamel may also occur (Demarco FF, Meireles SS, Masotti AS., Over-the-counter whitening agents: a concise review, Braz Oral Res. 2009; 23 Suppl 1: 64-70. Review).

Thus, the development of a method for whitening tooth enamel, which allows to achieve the desired results in a minimum number of procedures and at the same time does not lead to increased sensitivity of tooth enamel and other side effects, is an urgent task and demanded in the dental services market.

The process of whitening tooth enamel is based on the oxidation reaction of the chromophore groups of colored substances, as a result of which they lose their color. One suitable oxidizing agent is hydrogen peroxide, or substances releasing it (urea peroxide, sodium percarbonate, sodium perborate and others).

Known, for example, is a method of whitening tooth enamel, comprising the step of applying to the teeth an effective amount of a composition containing a whitening substance, and allowing the composition to remain on the teeth for from 45 to 90 seconds. Then carry out the stage of brushing the same composition. The whitening agent is hydrogen peroxide in combination with polyvinylpyrrolidone, and the concentration of said whitening agent in the composition is equivalent to 0.1-5% hydrogen peroxide. In addition, the composition contains an abrasive substance with calcium (Patent RU 2608441 C1, publ. 18.01.2017).

The disadvantages of this method are the lack of effectiveness and the presence in the composition of an abrasive substance that injures the enamel.

It is known that for the oxidation of coloring substances on tooth enamel in an acceptable time, a sufficiently high concentration of hydrogen peroxide or the use of activation methods — light, temperature, catalysis — are required. Under catalytic conditions, for example, in the presence of transition metal ions, hydrogen peroxide is capable of releasing reactive radicals, such as hydroxyl radicals (OH), which are stronger oxidizing agents. One example of catalytic oxidation by hydrogen peroxide is the Fenton reaction, where a ferrous salt is used as a catalyst (Fenton HJH (1894). "Oxidation of tartaric acid in presence of iron". J. Chem. Soc., Trans. (65): 899-911). In addition, the oxidative activity of hydrogen peroxide increases in an alkaline environment at pH> 8.

A known method of whitening tooth enamel, including applying to the teeth an effective amount of a composition containing a whitening substance and a catalytic amount of colloidal platinum, followed by irradiation with light, or without it. In this case, the whitening substance is hydrogen peroxide, carbamide peroxide, or calcium peroxide in a concentration equivalent to 5-10% hydrogen peroxide, the concentration of colloidal platinum is from 0.05% to 1%. After applying the composition to the teeth, it is aged from 15 to 30 minutes to achieve the effect. Additionally, light irradiation with a wavelength of 420-750 nm with an emitter power of 5-10 W can be used to catalyze the activation of hydrogen peroxide by colloidal platinum, or its salts upon irradiation with light [US 2014113244 A1, publ. 04.24.2014].

The main disadvantages of this method are the high cost of the platinum catalyst and the need for high-intensity light irradiation, which requires specialized equipment.

A known method of teeth whitening, including the preparation of a two-component composition consisting of a substance releasing hydrogen peroxide and an activator containing a mixture of an alkaline compound with a transition metal salt and applying the latter to the surface of the tooth enamel. The bleaching agent is hydrogen peroxide, urea peroxide, or another peroxide-releasing substance in a concentration equivalent to 0.1-30% hydrogen peroxide. The transition metal salt in the activator acts as a peroxide catalyst, while a stable compound of cobalt, iron, zinc, copper, manganese, or chromium is used as the salt. Any known substance capable of forming a pH above 8.0 in the final composition can be used as an alkaline substance. however, a stable compound of cobalt, iron, zinc, copper, manganese, or chromium is used as a salt. For tooth whitening, both components are mixed in predetermined proportions immediately before the procedure (US 20050249679 A1, publ. 10.11.2005).

The main disadvantage of this method is the need for preliminary mixing of the components in exact proportions before applying to the teeth. This complicates the bleaching procedure. Other disadvantages of this method include the instability of most salts of transition metals in an alkaline environment - they form poorly soluble hydroxides. In this case, the resulting hydroxides themselves are colored and are pigments capable of staining tooth enamel.

Closest to the claimed method, the prototype is a method of whitening tooth enamel, including applying an activating composition containing zinc oxide (as an activator of decomposition of hydrogen peroxide) to the tooth surface, followed by applying to the tooth surface a composition containing peroxide whitening agent in a concentration equivalent to 3-35% of hydrogen peroxide and irradiation of the whitened surface of the teeth with visible light in the wavelength range of 410-520 nm. The pH of the composition with zinc oxide is in the range of 6-9, and the pH of the composition with hydrogen peroxide is in the range

4-7. When mixing the two compounds, the pH shifts to the alkaline side, which also increases the activity of hydrogen peroxide and the effectiveness of whitening. The compositions can be applied sequentially - first, a composition containing zinc oxide is applied to the teeth to be whitened, and then the composition with hydrogen peroxide or the compositions can be mixed immediately before use and a mixture of them is applied to the teeth (US2015072302 A1, publ. 12.03.2015).

The main disadvantages of this method are the insufficient effectiveness of tooth whitening and the complexity and complexity of the procedure, since a composition containing water-insoluble particles of zinc oxide must first be applied to the surface of the teeth, or mixed with a composition containing hydrogen peroxide in predetermined proportions. In addition, in the known method, only two mechanisms of activation of hydrogen peroxide are involved - photocatalysis by particles of zinc oxide upon irradiation with light and due to a shift in pH to the alkaline region. In addition, in the known method does not provide for preliminary cleaning of the surface of the teeth, which reduces the effectiveness of whitening. In addition, due to the use of a sufficiently high concentration of hydrogen peroxide (3-35%), the risk of side effects increases. The known method has a limited area of use, since the whitening system cannot be used with whitening strips and can only be used by a professional dentist.

The objective of the invention is to provide a simpler and more effective method of whitening tooth enamel using an activating composition containing catalysts.

Effect: increasing the efficiency of the method, reducing the risk of side complications.

The problem is achieved by the proposed method, which consists in the following.

The activating composition (Activator) in the form of a solution having a pH of 8-9, containing sodium molybdate, sodium tungstate and a surfactant, is applied to the applicator (sponge). With a moistened applicator, they wipe the surface of the teeth to be whitened. Then the required amount of whitening gel containing a peroxide whitening agent is placed in an individual tray. Next, the mouthpiece with the gel is placed in the mouth so that the gel is evenly distributed on the surface of the teeth and does not fall on soft tissue. After installing the capa, a blue light source with a wavelength of 400-450 nm is sent to it, starting the process of parallel photoactivation for 10-30 minutes.

Instead of a whitening gel, strips of polymer material coated with a whitening gel (whitening strips) can be used, which are placed on the front surface of the teeth after treatment with the Activator.

The activating composition contains the following components, in mass. %: sodium molybdate - 0.1-1.0, sodium tungstate - 0.1-1.0, surfactant - 1.0-3.0; water is the rest.

Surfactants are selected from the group consisting of: sodium lauryl sulfate, sodium laureth sulfate, sodium lauroyl sarcosinate, polysorbate-20 and others.

As physiologically suitable excipient excipients, water can be used in various combinations in a concentration of from 50% to 90%, glycerol in a concentration of 2% to 20%, monopropylene glycol in a concentration of 2% to 20%, ethanol in a concentration of 0.5% to ten%.

In a preferred embodiment, water is used.

To reduce the sensitivity of enamel during bleaching, eugenol can be added to the Activator, which has a local anesthetic effect in a concentration of from 0.01% to 0.2%.

Saccharin, aspartame, sucralose, potassium acesulfame or a mixture thereof may be used as a sweetener to improve palatability. Menthol, natural essential oils, or suitable flavors may be used for flavoring.

The activator is packaged in bottles with a spray or foaming agent.

The whitening gel may contain hydrogen peroxide in a concentration of from 0.1% to 6.0%, or carbamide peroxide in a concentration of from 0.3% to 18%, or sodium perborate in a concentration of from 0.3% to 18%, or sodium percarbonate in concentrations from 0.3% to 18%. Acrylic polymer (carbomer) or carboxymethyl cellulose in a concentration of 1% to 3% can be used as a thickener. Water in a concentration of 1% to 50%, glycerin in a concentration of 10% to 50%, and monopropylene glycol in a concentration of 10% to 50%. As a neutralizing agent, triethanolamine or sodium hydroxide in a concentration of from 0.1% to 3% or another suitable basic substance can be used. Menthol, natural essential oils, or suitable flavors may be used for flavoring. Sodium saccharin, aspartame, sucralose, potassium acesulfame or a mixture thereof can be used as a sweetener to improve palatability.

To remineralize and protect the enamel during bleaching, sodium fluoride in a concentration of 0.05% to 0.2% and calcium hydroxyapatite nanoparticles in a concentration of 0.05% to 5% can be included in the composition.

To reduce the sensitivity of enamel during bleaching, potassium nitrate in a concentration of from 0.5% to 5% and strontium chloride in a concentration of from 0.5% to 5% can be used.

In an advantageous embodiment, the whitening gel contains the following components, in mass. %: carbamide peroxide - 12.0 (equivalent to 4.2% hydrogen peroxide); glycerin - 44.0; propylene glycol - 40.0; triethanolamine - 1.4; carbomer - 2.0; calcium hydroxyapatite - 0.5; sodium fluoride - 0.05; saccharin - 0.05.

Bleaching strips (strips of polymer material coated with a bleaching gel) may contain hydrogen peroxide in a concentration of 0.1% to 6%, or carbamide peroxide in a concentration of 0.3% to 18%, or sodium perborate in a concentration of 0, 3% to 18%, or sodium percarbonate in a concentration of 0.3% to 18%. In an advantageous embodiment, a gel containing in wt.% Is applied to the whitening strips: urea peroxide - 12.0; glycerin - 44.0; propylene glycol - 40.0; triethanolamine - 1.4; carbomer - 2.0; calcium hydroxyapatite - 0.5; sodium fluoride - 0.05; saccharin - 0.05.

In the preferred embodiment, for photoactivation, an LED lamp emitting at a wavelength of 400-450 nm is used (LED Teeth Lamp, manufacturer Huaer China).

The defining differences of the proposed method from the prototype are:

1. Previously, the surface of the teeth to be whitened, treated with an activating composition (Activator) containing, in mass. %: sodium molybdate - 0.1-1.0; sodium tungstate - 0.1-1.0; surfactant (surfactant) - 1.0-3.0; water - the rest, which allows to simplify the method and increase the efficiency of whitening.

2. After treatment with the Activator, the surface of the teeth to be whitened is treated with a whitening gel containing a peroxide whitening agent in a concentration equivalent to 0.1-6.0% hydrogen peroxide, mainly 4.2%, which improves the whitening efficiency and reduces the risk of side effects. complications due to a decrease in peroxide content, which is irritating to oral tissue and can damage tooth enamel.

3. The tooth surface treated with the Activator and the whitening gel is additionally irradiated with a blue light source with a wavelength of 400-450 nm for 10-30 minutes, which allows for the catalytic activation of hydrogen peroxide and to increase the degree of whitening without damaging the tooth enamel.

The catalytic activity of the activator is due to the formation of active peroxocomplexes during the interaction of hydrogen peroxide with soluble salts of molybdenum and tungsten acids. In addition, the alkali metal salts of molybdenum and tungsten acid in solution have an alkaline reaction and increase the pH of the medium. In an alkaline environment, the activity of hydrogen peroxide increases. In addition, the Activator carries out preliminary cleaning of teeth from surface plaque due to a surfactant, which also increases the effectiveness of whitening.

An activator containing sodium molybdate in a concentration of from 0.1% to 1.0% and sodium tungstate in a concentration of from 0.1% to 1.0%, together showing a synergistic effect and increasing the catalytic activity of the activator, can improve the effectiveness of tooth whitening. With a decrease in the concentration of catalysts below 0.1%, the whitening efficiency decreases sharply, and when using concentrations of catalysts above 1.0%, a noticeable increase in efficiency is not observed, therefore, high concentrations of catalysts are impractical.

To select the optimal catalysts and their concentrations, experiments were conducted on the oxidation of the dye methylene blue with hydrogen peroxide in the presence of different catalysts and without them. The concentration of hydrogen peroxide was 6%, the concentration of the catalyst was 0.1%, 0.5% and 1.0%, the concentration of methylene blue was 0.1 mg / ml. Catalyst options: sodium molybdate (Na2MoO4), iron chloride (FeCl3), sodium tungstate (Na2WO4), a mixture of sodium molybdate and sodium tungstate (Na2MoO4 + Na2WO4). The concentration of methylene blue was measured by HPLC 5 minutes after the start of the reaction. The results of the experiment are presented in table 1.

From table 1 it is seen that the highest oxidation efficiency of methylene blue is achieved using a combined catalyst consisting of sodium molybdate and sodium tungstate, which confirms their synergistic effect.

The invention is illustrated by the following examples of specific performance.

Example 1

8 human incisors were stained by soaking in strong black coffee for 3 days. After staining, the teeth were soaked in distilled water for 1 day to wash off soluble plaque. Half of the teeth were treated with Activator before bleaching, the second half was bleached without treatment with an activator. The activator contained 0.5% sodium molybdate, 0.5% sodium tungstate, 1.0% sodium lauryl sulfate, 98% water. The bleaching was carried out with a gel with a hydrogen peroxide content of 6%, followed by photoactivation by an LED lamp with a wavelength of 440 nm for 30 minutes. The tooth tone before and after bleaching was determined visually on the RS-20 scale. The experimental results are presented in table 2.

The average bleaching efficiency without activator was 8 tones on the RS-20 scale. The average bleaching efficiency with an activator was 10 tones on the RS-20 scale.

Example 2

Ten volunteers took part in the tests of the proposed method using a whitening system with and without an activator. In both cases, a whitening gel containing 12% carbamide peroxide (equivalent to 4.2% hydrogen peroxide) was used. Five volunteers carried out teeth whitening by the claimed method: The activator in the form of a solution having a pH of 8-9, containing 0.5% sodium molybdate, 0.5% sodium tungstate, 1.0% sodium lauryl sulfate, 98% water, was applied using a spray gun on applicator (sponge). Then a whitening gel containing in mass. %: carbamide peroxide - 12.0; glycerin - 44.0; propylene glycol - 40.0; triethanolamine - 1.4; carbomer - 2.0; calcium hydroxyapatite - 0.5; sodium fluoride - 0.05; saccharin - 0.05 was introduced into the mouthpiece and placed in the mouth so that the gel was evenly distributed over the surface of the teeth and did not get on the soft tissue. After installing the capa, a blue light source was directed at it using an LED lamp (LED Teeth Lamp, manufacturer Huaer China), emitting at a wavelength of 400-450 nm and photoactivation was carried out for 30 minutes.

In the second half of the volunteers, teeth whitening was carried out in a similar way, but without activator tooth treatment. Teeth tone was visually monitored on an RS-20 scale before and after the procedure. The results are presented in table 3.

The average bleaching efficiency without Activator was 6.8 tones on the RS-20 scale. The average bleaching efficiency with Activator was 9.6 tones on the RS-20 scale.

Example 3

Patient K., 47 years old, turned to a dental clinic with a request to carry out teeth whitening. A visual examination showed that the patient’s tooth enamel has a yellowish tint, in addition, there are spots and plaque on the teeth. The tone of the teeth on the RS-20 scale was S18.

The patient had teeth whitening of the claimed method.

An activating composition (Activator) having a pH of 8, containing, in wt. %: sodium molybdate - 0.1; sodium tungstate - 0.1; sodium lauryl sulfate - 3.0; water - 96.8; applied to the applicator (sponge), which wiped the surface of the teeth to be whitened. Then 2 g of the whitening gel was placed in an individual tray. The bleaching gel contained, in wt. %: carbamide peroxide - 12.0; glycerin - 44.0; propylene glycol - 40.0; triethanolamine - 1.4; carbomer - 2.0; calcium hydroxyapatite - 0.5; sodium fluoride - 0.05; saccharin -0.05. After installing the mouthpiece on the teeth to be whitened, a blue light source was directed at it using an LED lamp emitting in the 400-450 nm wavelength range (LED Teeth Lamp, China) and the photoactivation process was carried out for 20 minutes. The tone of the teeth on the RS-20 scale after the procedure was S16. The whitening efficiency was 4 tones on the RS-20 scale.

The proposed method provides high efficiency of teeth whitening at a low concentration of hydrogen peroxide, which helps to reduce the side effects of teeth whitening, and also reduces damage or irritation of the gums and mucous membranes of the oral cavity.

Claims (7)

1. A method for whitening tooth enamel, comprising applying an activating composition containing a hydrogen peroxide decomposition activator to the tooth surface, followed by applying a peroxide whitening agent to the tooth surface, and irradiating the whitened surface of the teeth with visible light for a period of time sufficient to whiten the teeth, characterized in that, first, an activating composition having a pH of 8-9, containing catalysts, surface-ac willow substance (surfactant) and water, then apply a whitening composition containing a peroxide whitening agent in a concentration equivalent to 0.1-6.0% hydrogen peroxide, while the irradiation of the whitened surface of the teeth is carried out with blue light with a wavelength of 400-450 nm for 10-30 minutes, and as catalysts, the activating composition contains sodium molybdate and sodium tungstate in the following components, wt.%: sodium molybdate 0.1-1.0 sodium tungstate 0.1-1.0 Surfactant 1.0-3.0 water rest 2. The method according to p. 1, characterized in that the activating composition contains a surfactant selected from the group comprising sodium lauryl sulfate, sodium laureth sulfate, sodium lauroyl sarcosinate, polysorbate-20. 3. The method according to p. 1, characterized in that the whitening composition contains a peroxide whitening agent in a concentration equivalent to 4.2% hydrogen peroxide. 4. The method according to p. 1, characterized in that the whitening composition contains, wt.%: Urea peroxide - 12.0; glycerin - 44.0; propylene glycol - 40.0; triethanolamine - 1.4; carbomer - 2.0; calcium hydroxyapatite - 0.5; sodium fluoride - 0.05; saccharin - 0.05. 5. The method according to p. 1, characterized in that as the source of blue light for irradiation using an LED lamp emitting in the wavelength range of 400-450 nm. 6. The method according to p. 1, characterized in that the whitening composition is applied to the surface of the teeth to be whitened using a tray or polymer strip with a pre-applied whitening composition.