Metal-carbon structure hybrid formulation for dental use in the treatment of dental hypersensitivity, demineralization and cavities

Abstract

The present invention relates to an antibacterial composition which, when applied to the surface of a tooth, allows remineralisation of the enamel to occur, said composition having very low toxicity for human use. When applied, the composition leaves no stains and does not alter the visible colour characteristics of the teeth to which it has been applied.

Claims

1. A composition having antimicrobial activity and which also promotes the remineralization of the surface of tooth enamel and dentin, comprising: a) an inorganic antimicrobial agent selected from the group consisting of copper, zinc, tin, and molybdenum, salts, oxides, and complexes thereof, wherein the inorganic antimicrobial agent is present in a concentration controlled by the addition of a solubilizing agent selected from solutions of ammonia; b) a promoter agent of remineralization of a surface of tooth enamel and dentin wherein the promoter agent comprises an ammonia complex of copper whose counter ion is fluoride (Cu(NH.sub.3).sub.6)F.sub.2 at a pH between 8 and 12; c) an inhibitor agent of the demineralization of tooth enamel and dentin; and d) a stabilizing agent having antimicrobial properties and which also helps the remineralization selected from the group consisting of derivatives of graphite oxides, graphene oxides, and mixtures thereof, wherein the promoter agent of remineralization, (Cu(NH.sub.3).sub.5)F.sub.2, is present in a concentration of between 100 and 40,000 ppm, and it also has an antimicrobial activity.

2. The composition according to claim 1, wherein the ammonia solution is present in a range of concentration in water between 1 and 50% v/v.

3. The composition according to claim 1, wherein the inhibitor agent of the demineralization is selected from halogen compounds.

4. The composition according to claim 1, wherein the stabilizing agent is present in a concentration of between 0.0001 and 0.02 g/ml.

5. The composition according to claim 3, wherein the inhibitor agent of the demineralization is selected from fluoride compounds.

6. The composition according to claim 1, wherein the inorganic antimicrobial agent is an ammonia complex of copper, zinc, tin, or molybdenum.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1. Photograph comparing the antimicrobial effect against microorganisms of the dental caries, from different commercial products and the composition of the present invention. The dark zone corresponds to the area where there is no bacterial growth. Composition of the present invention which possess a similar ability to Silver Diamine Fluorine. A) Chlorhexidine, B) Silver Diamine Fluorine, C) Silane Fluorine, D) Composition of the Invention.

(2) FIG. 2. Cell viability assay using mitochondrial activity technique (MTT). THP1 cell type. Commercial=(Silver Amino Fluorine Commercial Product), White, CHX=Chlorhexidine, BR1 and BR2=example of compositions of the present invention.

(3) FIG. 3. Scanning electron micrograph (SEM) of a biofilm formed by Streptococcus mutants on synthetic hydroxyapatite surface.

(4) FIG. 4. Photograph which shows a section of a) demineralized dentin by the biofilm effect and b) Non-demineralized dentin. White area is tooth enamel demineralized waste.

(5) FIG. 5. Vickers microhardness of hydroxyapatite disks (HaP). The values of not microbiologically treated dentin (initial), demineralized by the developed microbiological in-vitro model (Desmi) and after applying a composition of the present invention (Remi), are shown. The bar indicates its maximum and minimum value. Statistically significant difference is indicated with a p<0.00001 (n=90), and in a confidence interval of 95%.

(6) FIG. 6. Dentin Vickers microhardness. The values of not microbiologically treated dentin (initial), demineralized by the developed microbiological in-vitro model (Desmi) and after applying a composition of the present invention (Remi) are shown. Left chart composition effect of the present invention and right chart commercial agent effect. The bar indicates its maximum and minimum value. Statistically significant difference is indicated with a p<0.00001 o p<0.05, as appropriate (n=90), for a confidence interval of 95%. There is no significant statistical difference between the increase with respect to the sample remineralized with composition of the present invention and with the commercial product.

(7) FIG. 7. Vickers microhardness of enamel. The bar indicates its maximum and minimum value. The values of not microbiologically treated enamel (initial), demineralized by the developed microbiological in-vitro model (Desmi) and after applying a composition of the present invention (Remi) are shown. Left chart composition effect of the present invention and right chart commercial agent effect. Statistically significant difference is indicated with a p<0.00001 (n=90), for a confidence interval of 95%. There is no significant statistical difference between the increase with respect to the sample remineralized with composition of the present invention and with the commercial product.

(8) FIG. 8. Micrographs by scanning electron microscopy (SEM) of demineralized dentin before (A) and after (B) of applying a composition of the present invention.

(9) FIG. 9. Micrographs by scanning electron microscopy (SEM) of demineralized enamel before (A) and after (B) of applying a composition of the present invention.

(10) FIG. 10. UV-Vis spectrum of components of the composition of the present invention and their interactions: A: Cu(H.sub.2O).sub.6F.sub.2; B: Cu(NH.sub.3).sub.6F.sub.2; C: Cu(NH.sub.3).sub.6F.sub.2+GO.

SUMMARY OF THE INVENTION

(11) The present invention corresponds to a composition with antibacterial activity, and which applied to a dental surface allows the remineralization of the enamel, wherein the composition has a low toxicity for human use, and wherein its application does not leave stains nor change the visible color features in dental pieces wherein the composition has been applied.

DETAILED DESCRIPTION OF THE INVENTION

(12) In a first aspect, the invention corresponds to a composition or antimicrobial agent which also promotes the remineralization of the surface of tooth and dentin enamel.

(13) In a particular embodiment, the composition comprises at least 3 components selected among: i. An inorganic antimicrobial agent; ii. An agent which promotes the remineralization of a surface of tooth and dentin enamel; iii. An agent which inhibits the demineralization of tooth and dentin enamel; and iv. A stabilizing agent which may also have antimicrobial properties and can help to the remineralization.

(14) In a more specific embodiment, the inorganic antimicrobial agent is selected from metals and their salts, oxides and/or complexes, including copper, zinc, tin, and molybdenum derivatives, such as ammonia complexes of these metals, in a high concentration controlled by the addition of a solubilizing agent selected from different ammonia solutions. The ammonia solution is presented in a range of concentration in water between 1 and 50% v/v.

(15) In another specific embodiment, the promoter of remineralization is selected among halogens, in particular, fluorides compounds, to which it can also add another particulate mineralizing agents, such as ceramics. These same promoters can also inhibit the demineralization of the tooth.

(16) In another specific embodiment, the stabilizing agent is selected from different carbon structures, specifically, those derived from the graphene and/or graphite, more specifically from graphite oxides and graphene oxides, and when the stabilizing agent is selected from graphite oxides and graphene oxides, said stabilizing agent also presents antimicrobial properties and helps the remineralization.

(17) In particular, without the intention of limiting the scope of the invention, the more preferred components correspond to copper complexes with fluorine. More specifically, the copper is composed by a copper ammonia complex whose counterion is (Cu(NH.sub.3).sub.6)F.sub.2 fluoride to a high pH, typically between 8-12; the more preferred remineralization promoter agent and the demineralization inhibitor is fluorine; and the more preferred stabilizing agent is a derivate from graphite, more specifically a graphite oxide or graphene oxide.

(18) In a more specific embodiment, the composition of the present invention also comprises another stabilizing agents derived from carbon, such as graphene, and its oxides. In yet another more specific embodiment the antimicrobial and remineralizing agent, in particular (Cu(NH.sub.3).sub.6)F.sub.2, is present at a concentration of between 100 and 40,000 ppm, and the stabilizing agent, in particular a derivate from graphene oxide type graphite, is in a concentration of between 0.0001 and 0.02 g/ml.

EXAMPLES OF APPLICATION

Example 1: In Vitro Evaluation of the Antibacterial Capacity

(19) Tests to demonstrate the antibacterial effect of the composition of the present invention were performed, in particular using 25,000 ppm of an aqueous solution of (Cu(NH.sub.3).sub.6)F.sub.2 ammonia in presence of 0.002 g/ml of graphite oxide, comparing it with products which are currently available in the market and which is considered the standard in the field. These tests have been performed on the main bacterial species associated with dental caries. It is concluded that the composition of the present invention has the ability to remove the bacteria related with the dental caries to a similar level than other commercial products. It is only exceeded by chlorhexidine, which is a very active compound, but it does not have the other functionalities presented by the composition of the present invention, which is observed in FIG. 1, where the areas of inhibition halos for chlorhexidine is 659 mm.sup.2; Product on the market 200 mm.sup.2; composition of the present invention 278 mm.sup.2.

Example 2: In Vitro Evaluation of Cytotoxicity

(20) To evaluate the cytotoxicity of the composition of the present invention, viability experiments were performed of a cell culture exposed to the composition of the present invention. In particular, the viability of (TPH1) human cells was quantified by a mitochondrial activity assay (MTT) in contact with different concentrations of the composition of the present invention. In addition, this result was compared to other commercial products currently used in clinical practice routine. It is observed that the commercial product is extremely toxic (0% viability) independent of the used dilution. On the other hand, the composition of the present invention, in its formulation with and without the stabilizing, presents high viability to dilutions of the order of 10.sup.3 o 10.sup.4. It is also observed that any product, including the chlorhexidine, present a degree of toxicity, therefore, what is the most important is that the composition of the present invention is much less toxic than the commercially available alternatives (FIG. 2).

Example 3: Ability of Remineralization Using an In Vitro Model of Dental Caries

(21) At this stage it is aimed to evaluate in an in vitro model the remineralizing ability of the composition of the present invention. It has been mounted an in vitro model of dental caries lesions development by the metabolic activity of microbial species on human teeth by a monospecie biofilm. This allows you to produce lesions similar to those that occur in a real-world scenario.

(22) Our first result is related to validate the microbiological model of in vitro dental caries. The dental caries model described by Ccahuana-Vásquez y Cury (2010 April-June; 24(2):135-41) was used, in which the simulation of a cariogenic environment is carried out by the exposure of enamel blocks, dentin or calcium hydroxyapatite to sucrose, previous formation of a monospecie biofilm of Streptococcus mutans. (FIG. 3) Thus, it is allowed to obtain a demineralization zone, which can then be remineralized with an experimental remineralizing agent.

(23) The lesions of non-cavitated artificial dental caries generated according the previous protocol, are subjected to different protocols of remineralization using different concentrations and exposure times to a composition according to the described in the present invention. In addition, differences in the remineralization between this product with those currently used for this purpose will be determined.

(24) For the evaluation of the remineralizing effects, indicators of tissue superficial hardness change (Vickers microhardness) will be used, the obtained results obtained are given account below:

(25) Hydroxyapatite Disks:

(26) According to the obtained data (n=90) the initial hardness of the Hydroxyapatite disks (HAP) is of 5,480.9 MPa with a confidence interval of 95% between 5,398.6 MPa and 5,562.3 MPa. After the specimens were subjected to the in vitro model of dental caries lesions development simulating the conditions of the mouth the hardness is 5,262.2 MPa with a confidence interval between 5,192.6 y 5,311.3. This difference between the initial disk and the treated one in the dental caries model, are statistically significant with p<0.0001. After the specimens were subjected to the remineralization protocol with the composition of the present invention, the hardness values are 5,416.2 MPa with an interval of 95% confidence between 5,375 and 5,456.4. The average difference observed is of 228.5 MPa with a confidence interval of 95% between 130.4 and 326. (FIG. 5). This difference is statistically significant when is compared with the controls with a value p<0.00001. Therefore, it is demonstrated that the presence of the composition of the present increases the hardness of the injured material to values close to which the system had before the injury. This is an indicator that the composition product of the present invention is able to remineralize.

(27) Dentin and Enamel:

(28) Real teeth were also evaluated (FIGS. 6 and 7). Dentin has an initial value of 748.2 MPa, which after being subjected to the in vitro demineralization decreases to 152.9 MPa. Using our formulation of the present invention, this value increases to 259.9 MPa, with a statistical significance (p<0.00001) In the enamel the trend is the same. In both cases, the commercial product presents the same increases in hardness in our materials.

(29) The remineralizing ability of our formulation is confirmed by micrographs by scanning electron microscopy (SEM) of dentin and enamel, demineralized and after applying composition of the present invention. It is clearly observed that the samples after being subjected to composition of the present invention present an associated closure to the remineralization.

Example 4: Evaluation of the Molecular Interaction of Components of the Composition of the Present Invention

(30) The composition of the present invention has been characterized as a metal in solution, but as ammonia complex of theoretical formula of Cu(NH.sub.3).sub.6F.sub.2. In FIG. 6 it is observed the absorption spectrum UV/Visible which confirms this structure.

(31) The shift toward smaller wavelengths gives an account of the formation of ammonia metal complex which is observed in an increase of the solubility of the salt in this solution which allows to reach fluoride concentrations close to 30,000 ppm, which is impossible in aqueous solution.

INDUSTRIAL APPLICATION

(32) The present invention finds application in the pharmaceutical or cosmetics industry, more specifically in the production of compositions for the care of oral health.