Bleaching Gel

Abstract

Disclosed is a dental bleaching gel composition with high electric conductivity. It was the object of the present invention to provide a bleaching gel composition that is less initiating than prior art gels, and is highly efficient such that it can bleach within shorter time. The composition includes a peroxide, or a peroxide releasing compound such as carbamide peroxide, sodium perborate, or sodium percarbonate as a bleaching agent, a cross-linked polyacrylate polymer as a thickening component, and electrical conductivity enhancing ingredients such as electrolytes.

Claims

1. (canceled)

2. The method according to claim 16 wherein the electrical conductivity enhancing ingredient is at least one of a group consisting of alkali nitrate in an amount of 1 to 5% w/w and alkali hydroxide in amount of 1 to 5% w/w.

3. The method according to claim 16, wherein the pH of the gel is 5-7.

4. The method according to claim 16, wherein the aqueous vehicle comprises at least one alcohol.

5. The method according to claim 2, wherein the alkali hydroxide is potassium hydroxide and/or wherein the alkali nitrate is potassium nitrate.

6. The method according to claim 17, wherein the amount of glycerin is 20 to 30% w/w; and/or wherein the amount of water is 25 to 50% w/w.

7. The method according to claim 16, wherein the amount of peroxide is 3 to 35% w/w.

8. The method according to claim 16, wherein the amount of a cross-linked polyacrylate polymer is 1 to 5% w/w.

9. The method according to claim 16, wherein the dental bleaching gel further comprises a fluoride salt in amount of 0.1 to 1.0% w/w.

10. The method according to claim 16, wherein the dental bleaching gel further comprises at least one alkali hydroxide w/w in amount of 0.5 to 3.0% w/w.

11. The method according to claim 16, wherein the dental bleach gel further comprises a polymeric binder.

12. The method according to claim 16, wherein the dental bleaching gel further comprises disodium ethylenediamine tetraacetic salt (EDTA) in an amount of 0.1 to 2.0% w/w.

13. The method according to claim 16, wherein the dental bleaching gel further comprises flavoring ingredients in an amount of 0.1 to 0.5% w/w.

14. The method according to claim 13, wherein the flavoring ingredients are at least one of a group consisting of saccharin sodium salt hydrate and peppermint oil and a mix of both of them.

15. A method of bleaching the teeth comprising the steps of: applying to the teeth to be bleached a layer of dental bleaching gel with electrical conductivity higher than 250 microsiemens/cm; applying to the teeth covered by a layer of gel with electrical conductivity higher than 250 microsiemens/cm electric current of at least 1 milliampere; and bleaching the teeth.

16. The method of claim 15, wherein the dental bleaching gel applied to the teeth is a dental bleaching gel composition comprising: a peroxide or peroxide releasing compound, a cross-linked polyacrylate polymer, an aqueous vehicle; and at least one electrical conductivity enhancing ingredient; wherein the electrical conductivity of the gel is at least 250 microsiemens/cm.

17. The method according to claim 4, wherein the alcohol is selected from glycerin, propylene glycol, and mixtures thereof.

18. The dental bleaching gel according to claim 11, wherein the polymeric binder is polyvinylpyrrolidone in an amount of 0.5 to 2.0% w/w.

Description

EXAMPLE 1 DENTAL BLEACHING GEL

[0043] A gel comprising 6% hydrogen peroxide was prepared using the following ingredients:

TABLE-US-00001 Ingredient Concentration (%) w/w Glycerin 25-30 Carbopol 940/Carbopol 980 1-5 Hydrogen Peroxide 30% 20-25 Deionized Water 40-50 Potassium Nitrate 2-3 Potassium Hydroxide (50% in water) 2-3 PVP(Polyvinylpyrrolidone) 0.5-2   EDTA (Disodium Ethylenediaminetetraacetic salt) 0.1-1   Saccharin sodium salt hydrate 0.2 Peppermint oil 0.2

[0044] 120 gram of the 6% HP dental gel bleaching composition were prepared by combining the following ingredients according to the following procedure:

[0045] 3.6 g of potassium nitrate were mixed with 0.24 g of saccharine, 0.6 g EDTA and dissolved at room temperature in 40 ml of water. Two to three drops of KOH where added to the mixture.

[0046] A mixer was used to stir the mixture for about 5-10 (five-ten) minutes. At the beginning of the stirring 3 grams of Carbopol® (cross-linked polyacrylate polymer) was added to the mixture. The mixture was stirred at a low speed of 200-250 RPM.

[0047] After about 5-10 minutes of stirring the mixture, 40 ml (32 g) of glycerol were added to the mixture and the stirring continued for another 5-10 minutes at a speed of 500-700 RPM.

[0048] Following this 24 ml of hydrogen peroxide (30% W/W solution) were added to the mixture and the mixture was stirred for another 5-10 minutes at a speed of 500-700 RPM.

[0049] Three (3) milliliter of potassium hydroxide 50% W/W solution where added to the mixture and the mixture stirring continued for another five (5-10) minutes at a speed of 750-1000 RPM.

[0050] Peppermint oil in amount of 0.2% w/w was added to the mixture and stirred for about a minute at a speed of 1000 RPM.

[0051] PVP (Polyvinylpyrrolidone) in an amount of 0.6 g was added to the almost ready composition and stirred for another 10 minutes at a speed of 1000 RPM.

[0052] The process produced about 120 g of ready to use gel composition. The produced dental bleaching gel composition was stable and was able to adhere and retain in a dental tray in place against a person's teeth. The dental bleaching composition had a conductivity of 500-700 microsiemens/cm.

[0053] Pearl™ dental tray was used to test the bleaching properties of the bleaching gel composition of Example 1. Application of electric current of about 6 milliampere for 5 minutes bleached or whitened the teeth. The result was compared visually to teeth bleaching procedure using the Pearl™ teeth whitening system and commercially available teeth bleaching gels with electrical conductivity below 200 microsiemens/cm. The current teeth bleaching gel was found to result in two or three additional whiting shades as compared to the teeth bleaching performed by the Pearl™ system for 5 minutes using commercially available teeth bleaching gel.

[0054] Gel composition conductivity was measured by Digital Conductivity Meter model Traceable 4063, manufactured by Control Company, Friendswood, Tex. 77546, USA, (www.control3.com). The measurement was performed by a probe that contained platinum electrodes and a thermistor.

EXAMPLE 2 DENTAL BLEACHING GEL

[0055]

TABLE-US-00002 Ingredient Concentration w/w (%) Glycerin/propylene glycol 25-30 Carbopol 1-5 Hydrogen Peroxide 30% w/w 25-35 Deionized Water 30-40 Potassium Nitrate 2-3 Potassium Hydroxide (50% in water) 2-3 PVP( Polyvinylpyrrolidone) 0.5-2   EDTA ( Disodium Ethylenediaminetetraacetic salt) 0.1-1   Saccharin sodium salt hydrate 0.2 Peppermint oil 0.2

[0056] In Example 2, 9% HP w/w gel dental bleaching composition was prepared using the following ingredients and according to the following procedure:

[0057] 3.6 g of potassium nitrate were mixed with 0.24 g saccharine, 0.6 g EDTA and dissolved at room temperature in 42 ml of water. Two or three drops of KOH were added to the mixture.

[0058] A mixer was used to stir the mixture for about 5-10 minutes. At the beginning of the stirring 3 grams of Carbopol® were added to the mixture. The mixture was stirred at a low speed of 200-250 RPM.

[0059] After about 5-10 minutes of stirring the mixture, 40 ml (32 g) of glycerol were added to the mixture and the stirring continued for another 5-10 minutes at a speed of 500-700 RPM.

[0060] Following this 36 ml of hydrogen peroxide (30% solution) were added to the mixture and the mixture was stirred for another 5-10 minutes at a speed of 500-700 RPM.

[0061] Three (3) milliliter of potassium hydroxide 50% w/w solution where added to the mixture and the mixture stirring continued for another five (5-10) minutes at a speed of 750-1000 RPM.

[0062] Peppermint oil in amount of 0.2% w/w was added to the mixture and stirred for about a minute at a speed of 1000 RPM.

[0063] PVP (Polyvinylpyrrolidone) in an amount of 0.6 g was added to the almost ready composition and stirred for another 10 minutes at a speed of 1000 RPM.

[0064] The process produced about 120 g of ready to use gel composition. The produced dental bleaching gel composition was stable and was able to adhere and retain in a dental tray in place against a person's teeth. The dental bleaching composition had a conductivity of 250-500 microsiemens/cm. Syneron Medical Ltd., Pearl™ dental tray was used to test the bleaching properties of the bleaching gel composition of Example 2. Application of electric current of about 10 milliampere for 5 minutes bleached or whitened the teeth. The result was compared visually to teeth bleaching procedure using the Pearl™ teeth whitening system and the current gel and commercially available teeth bleaching gels with electrical conductivity below 200 microsiemens/cm. The current gel was found to be superior to the commercially available teeth bleaching gels and resulted in 3 to 4 additional white shades as compared to teeth bleaching performed by using the Pearl™ tray with commercially available teeth bleaching gel for 5 minutes.

[0065] Gel composition conductivity was measured by Digital Conductivity Meter model Traceable 4063, manufactured by Control Company, Friendswood, Tex. 77546, USA, (www.controil3.com). The measurement was performed by a probe that contained platinum electrodes and a thermistor.

EXAMPLE 3 DENTAL BLEACHING GEL

[0066]

TABLE-US-00003 Concentration (%) Ingredient w/w Glycerin /propylene glycol 20-30 Carbopol 940/ Carbopol 980 1-5 Hydrogen Peroxide 30% 25-35 Deionized Water 30-40 Potassium Nitrate 2-3 Sodium fluoride 0.1-1.0 Potassium hydroxide 30% w/w 2-3 PVP (Polyvinylpyrrolidone) 0.5-2.0 EDTA 0.1-1   (Disodium Ethylenediaminetetraacetic salt) Saccharin sodium salt hydrate 0.2 Peppermint oil 0.2

[0067] A dental bleaching composition was prepared by combining the ingredients (in weight percent) as shown in the above table.

[0068] The procedure produced about 120 g of ready to use gel composition. The produced dental bleaching composition was stable and was able to adhere and retain a dental tray in place against a person's teeth. The dental bleaching composition had a conductivity of 800-1000 microsiemens/cm. Pearl™ dental tray was used to test the bleaching properties of the bleaching gel composition of Example 3. Application of electric current of about 10 milliampere for 5 minutes bleached or whitened the teeth. The result was compared visually to teeth bleaching procedure using the Pearl™ tray with commercially available teeth bleaching gels with electrical conductivity below 200 microsiemens/cm. The results of the teeth bleaching using the present gel were found to be superior to teeth bleaching performed by the Pearl™ system for 5 minutes using the commercially available teeth bleaching gels with low electric conductivity.

[0069] Gel composition conductivity was measured by Digital Conductivity Meter model Traceable 4063, manufactured by Control Company, Friendswood, Tex. 77546, USA, (www.control3.com). The measurement was performed by a probe that contained platinum electrodes and a thermistor.

EXAMPLE 4 COMPARATIVE TEETH WHITENING TEST RESULTS

[0070] In order to compare electric current assisted teeth whitening method efficacy with the non-current assisted teeth whitening methods a test procedure was set. The experimental set-up included a mock-up of twenty teeth stained to different levels of shades. The mock-up teeth were cut perpendicular to their long axis and divided into a total of forty mock-up teeth. Than the prepared specimens were divided into two groups; Group A and Group B with each group including twenty teeth with shades identical to the shades of the second group.

[0071] Twenty teeth of Group A were treated using the present electrically conductive whitening gel. A total of ten teeth whitening treatments was conducted. Duration of each treatment was 5 minutes. Applied electrical current was about 10 milliampere.

[0072] Twenty teeth of Group B were treated using commercially available teeth whitening gels without application of electrical current. A total of ten teeth whitening treatments was conducted. The duration of each treatment was 5 minutes.

[0073] Whitening of the teeth with an electrically conductive gel assisted by electric current resulted in 35% better average teeth whitening than using commercially available gels without electric current application. Teeth shades were measured by SpectroShade spectrometer commercially available from MHT Optic Research AG, CH-8155 Niederhasli Switzerland. Tooth color shade was evaluated using an established and standardized scale of 16 shades, VITA Classical shade guide (Vident™, Brea, Calif. USA). Teeth shades were measured immediately following completion of each teeth whitening treatment.

[0074] Use of electrically conductive gel with application of electric current of about 3-15 milliampere whitened a larger amount of teeth to the whitest A1 color. Electric current assisted tooth whitening treatment was almost 100% more effective than treatment with commercially available gels and without electric current.

[0075] Use of electrically conductive gel with application of electric current bleached 90% of the teeth to the whitest A1 shade as compared to only 45% of the teeth treated by commercially available teeth whitening gels and without application of electric current.

[0076] 100% of the Group A teeth with baseline shade of A3 after treatment with electrically conductive whitening gel and application of electric current have become teeth with A1 shade as compared with 64% of the teeth treated by commercially available dental whitening gel and without application of electric current.

[0077] 100% of the Group A teeth after treatment with electrically conductive whitening gel and application of electric current have shown whitening of seven shades, as compared with 50% of the teeth treated by commercially available dental whitening gel and without application of electric current.

[0078] 25% of the Group A teeth treated with electrically conductive whitening gel and application of electric current have shown whitening of ten shades, as compared with 5% of the teeth treated by commercially available dental whitening gel and without application of electric current.

[0079] Improvement in whitening of Group B teeth (without application of electric current) has stopped after about 40 min of accumulated treatment time, whereas improvement in teeth whitening results of Group A teeth (with application of electric current) continued even after 50 min of accumulated treatment time.

EXAMPLE 5 DENTAL BLEACHING GEL

[0080] Further formulations were prepared and tested, wherein the bleaching agent was carbamide peroxide. Furthermore, no binding agent is present.

TABLE-US-00004 Ingredient Concentration w/w (%) Glycerin/propylene glycol 25-30 Carbopol 1-5 Carbamide peroxide 25-35 Deionized Water 30-40 Potassium Nitrate 2-3 Potassium Hydroxide (50% in water) 2-3 EDTA ( Disodium Ethylenediaminetetraacetic salt) 0.1-1   Saccharin sodium salt hydrate 0.2 Peppermint oil 0.2

[0081] The formulation was tested as above in example 4. The results are shown in the following table. The formulation using carbamide peroxide was also active when applied and activated with micro-current. This formulation was also stable although it did not comprise a binding agent showing that the essential ingredients as defined in claim 1 are sufficient to prepare a stable and active bleaching gel.

Tooth Bleaching Results Using the Current Gel and Electric Current of 3-15 Milliampere

[0082]

TABLE-US-00005 Tooth Tooth Baseline shade No. Shade change T2 A3 7 T4 A3 7 T6 A3.5 10 T8 A3 7 T10 A3 7 T12 A3 7 T14 C4 7 T16 D3 8 T18 A3 7 T20 A3.5 10 T22 A3 7 T24 C4 11 T26 A3 7 T28 A3.5 10 T30 A3 7 T32 A3 7 T34 A3.5 10 T36 A3 7 T38 A3 7 T40 A3 7 Average 7.85
Tooth Bleaching Results Using a Commercially Available Gel without Electric Current Application

TABLE-US-00006 Tooth Tooth Baseline shade No. Shade change T1 A3 7 T3 A3 7 T5 A3.5 4 T7 A3 7 T9 A3 4 T11 A3 7 T13 D3 5 T15 D3 5 T17 A3 4 T19 A3 7 T21 A3 4 T23 A4 5 T25 A3.5 10 T27 A3 4 T29 A3.5 3 T31 A3 7 T33 A3.5 5 T35 A3 7 T37 A3 7 T39 A3 7 Average 5.8