WO2019126890A1 - Composition for repairing incipient tooth decay and method for preparing same - Google Patents

Composition for repairing incipient tooth decay and method for preparing same Download PDF

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Publication number
WO2019126890A1
WO2019126890A1 PCT/CL2018/050137 CL2018050137W WO2019126890A1 WO 2019126890 A1 WO2019126890 A1 WO 2019126890A1 CL 2018050137 W CL2018050137 W CL 2018050137W WO 2019126890 A1 WO2019126890 A1 WO 2019126890A1
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composition
matrix
nano
mixture
particles
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PCT/CL2018/050137
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Spanish (es)
French (fr)
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Cristián Mauricio Covarrubias Gallardo
Guillermo Octavio SANDOVAL CARRASCO
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Universidad De Chile
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K33/00—Medicinal preparations containing inorganic active ingredients
    • A61K33/06—Aluminium, calcium or magnesium; Compounds thereof, e.g. clay
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K33/00—Medicinal preparations containing inorganic active ingredients
    • A61K33/42—Phosphorus; Compounds thereof
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/80—Preparations for artificial teeth, for filling teeth or for capping teeth
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K8/00—Cosmetics or similar toiletry preparations
    • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
    • A61K8/19—Cosmetics or similar toiletry preparations characterised by the composition containing inorganic ingredients
    • A61K8/20—Halogens; Compounds thereof
    • A61K8/21—Fluorides; Derivatives thereof
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K8/00—Cosmetics or similar toiletry preparations
    • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
    • A61K8/19—Cosmetics or similar toiletry preparations characterised by the composition containing inorganic ingredients
    • A61K8/24—Phosphorous; Compounds thereof
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61Q—SPECIFIC USE OF COSMETICS OR SIMILAR TOILETRY PREPARATIONS
    • A61Q11/00—Preparations for care of the teeth, of the oral cavity or of dentures; Dentifrices, e.g. toothpastes; Mouth rinses
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/624—Sol-gel processing

Definitions

  • the present invention relates to preparations for dental use, in particular it provides a composition for the repair of incipient dental caries comprising a matrix and nano-particles, and a method for the preparation of said composition.
  • Dental caries is a disease of high prevalence in the world, whose prevention and treatment is composed of a varied set of clinical and social practices. Dental caries results from a demineralization process of the hard dental tissue constituted by the hydroxyapatite mineral phase, due to the action of the organic acids generated as a result of the fermentation metabolism of the carbohydrates carried out by the bacteria adhered to the tooth surface (RH Selwitz, Al Ismail, NB Pitts, Dental Caries, Lancet, 369, 51, 2007).
  • the demineralization process progresses over time, producing an initial non-cavitated caries lesion known as a white spot lesion (LMB), early or incipient caries, which manifests as a loss of translucency of the enamel, the presence of an opaque and dull surface; and that at the micro and nano-scale is characterized by the increase of the microporosity and the spaces between the hydroxyapatite crystals.
  • LMB white spot lesion
  • the degree of demineralization progresses, resulting in the cavitation of the lesion.
  • ICON ® is an acrylic resin that has no bioactive components, and, therefore, does not have the ability to stimulate the process of remineralization and repair of the injury.
  • a product known in the state of the art as a remineralizing agent is the bioceramic material called bioactive glass (VB), known for its ability to stimulate the crystallization of hydroxyapatite, promote the osteogenic activity of bone tissue forming cells and present a certain degree of antimicrobial activity (JR Jones, Review of bioactive glass: from Hench to hybrids, Biomater Act, 9, 4427, 2013). Due to its proven ability to form crystalline hydroxyapatite in contact with physiological media, this material of typical composition 45% Si0 2 - 24.5% Na2Ü - 24.5% CaO - 6% P 2 O 5 is used as active remineralizing agent in some dental products, mainly aimed at solving the problem of tooth sensitivity.
  • the bioactive glass used in commercial dental application products is in the form of a microparticle ( ⁇ 12 pm) and under the name of Novamin ® technology.
  • bioactive glass is a potential remineralizing agent for non-cavitated lesions
  • the formulations made up to date comprise a commercial paste with micrometric VB or VB powder suspended in water, which does not allow a prolonged action similar to varnish fluoride or ICON ® infiltrating resin.
  • polymer matrices with VB nanoparticles these are oriented to the regeneration of bone tissue, so the composition is more complex and combines the bioactivity of the inorganic particles with the support properties of a three-dimensional polymer matrix.
  • a first object of the invention is a composition for the repair of incipient dental caries comprising a matrix and nano-particles including said matrix, characterized in that said matrix and said nanoparticles include silicon, calcium and phosphate ions, wherein preferably said matrix is a gel.
  • said matrix and the nanoparticles comprise silicon dioxide (S1O2), calcium oxide (CaO) and phosphorus pentoxide (P2O5). More particularly, the nano-particles additionally comprise fluorine (F).
  • the matrix has a molar composition corresponding to 58Ca0: 36Si02: 6P205, and the nanoparticle has a molar composition corresponding to 58SiO 2 : 40CaO: 5P 2 Os: F.
  • the composition comprises between 97.5-99.5% matrix and 0.5-2.5% nanoparticles, more preferably it comprises between 97.5-99.5% matrix with molar composition corresponding to 58Ca0 : 36Si0 2 : 6P 2 0s and 0.5-2.5% nanoparticles of molar composition corresponding to 58SiO 2 : 40CaO: 5P 2 O 5 : F.
  • a second object of the invention is a method for the preparation of a composition for the repair of incipient dental caries, comprising the steps of:
  • nano-particles that include silicon, calcium and phosphate ions by the sol-gel method
  • the nano-particles are prepared by the steps of:
  • the solution of calcium nitrate (Ca (N03) 2 '3H 2 0) in water has a concentration of between 6.0-7.0% w / v
  • the dihydrogen solution of ammonium phosphate ( NH4H2PO4) in water has a concentration between 0.10-0.20% w / v
  • the solution of ammonium fluoride (NH4F) in water has a concentration between 0.01-0.05% w / v.
  • the precipitate with the nano-particles is purified by centrifugation / re-dispersion in water at 12,000 rpm, and then lyophilized and calcined at 700 ° C for 3 hours.
  • the precursor solution of a matrix is prepared by the steps of: hydrolyzing tetraethylortisolicate Si (OC2Hs) 4 in 95% acidified ethanol; Y
  • the tetraethylortisolicate Si (OC2Hs) 4 in ethanol has a concentration between 27-29% v / v, the concentration of triethylphosphate (C 2 Hs) 3P0 4 (> 99%) in the precursor solution is between 2.0-2. , 3% v / v, and the concentration of
  • Ca (N03) 2 '3H 2 0 in the precursor solution is between 3.0-3.5% w / v.
  • FIG. 1 shows electron microscopy images of SEM scanning of samples before being subjected to bioactivity assays.
  • FIG. 1A control
  • FIG. 1B Fluoride varnish on white spot lesions
  • FIG. 1C bioactive glass gel without nano-particles on white spot lesions
  • FIG.1D bioactive glass gel with 1% fluorinated bioactive glass nanoparticles on white spot lesions.
  • FIG. 2 shows electron microscopy images of SEM scanning of samples after undergoing bioactivity assays.
  • FIG 2A Fluoride varnish on white spot lesions
  • FIGG 2B bioactive glass gel without nanoparticles on white spot lesions
  • FIGG 2C bioactive glass gel with 1% fluorinated bioactive glass nanoparticles on white spot lesions
  • FIGG 2D healthy tooth enamel.
  • FIG. 3 show infrared spectrum graphs of samples before and after undergoing bioactivity assays.
  • FIG. 3A samples treated with fluoride varnish
  • FIG. 3B samples treated with bioactive glass gel
  • FIG. 3C samples treated with bioactive glass gel with 1% fluorinated bioactive glass nanoparticles.
  • FIG. 4 shows SEM scanning electron microscopy images of samples treated with bioactive glass gel and bioactive glass gel with 1% fluorinated bioactive glass nanoparticles after being subjected to acid challenge tests.
  • the present invention relates to a composition for the repair of incipient dental caries, comprising a matrix (preferably a gel) and nanoparticles, both biologically active, which, when mixed, surprisingly potentiate the bioactivity of the composition.
  • a matrix preferably a gel
  • nanoparticles both biologically active
  • both the matrix and the nano-particles comprise silicon, calcium and phosphate ions that allow remineralization of the incipient caries lesion by forming a mineral phase equivalent to the hydroxyapatite of the original enamel.
  • the product described in the present invention is completely novel, because in the state of the art to date there is no known composition that both the matrix and the nano-particles that it includes have the same chemical elements (silicon, calcium and phosphate ions). ).
  • the present invention also relates to a method of preparing said composition, which comprises mixing the matrix and the previously prepared nanoparticles, preferably in a proportion between 97.5-99.5% of the matrix and 0.5-2.5% of the nanoparticles, more preferably between 98.5-99.0% of the matrix and 1.0-1.5% of the nanoparticles, without being limited to said proportions.
  • gel an intricate network of particles joined together with enough space between them to trap water molecules and other compounds in its three-dimensional structure, which forms a semi-solid with two phases: a solid phase and a liquid .
  • the gel not only fulfills the function of structural support, but is also biologically active.
  • nano-particle a particle that has a dimension less than 100 nm, which behaves as a complete unit with respect to its physicochemical properties.
  • bioactive or “biological activity” a material that provides an appropriate biological response and results in the formation of a bond between the material and the tissue where it is applied.
  • a “ceramic bioactive” is one that forms biologically active hydroxyapatite through chemical reactions of its surface with the surrounding liquid fluids.
  • bioactive glass a glass-ceramic material with biological activity whose composition contains mainly S1O 2 , CaO and P 2 O 5 . It may additionally contain Na2Ü or mineral elements such as Cu, Li, F, etc.
  • a first object of the present invention relates to a composition for the repair of incipient dental caries, comprising a matrix and nano-particles included and / or dispersed in said matrix, wherein said matrix and said nano-particles include silicon ions, calcium and phosphate.
  • the matrix is a gel comprising silicon dioxide (S1O2), calcium oxide (CaO) and phosphorus pentoxide (P2O5), preferably in a molar composition corresponding to 58Ca0: 36Si02: 6P20s.
  • said matrix is bioactive glass (VB) in gel.
  • the nano-particles also comprise silicon dioxide (S1O2), calcium oxide (CaO) and phosphorus pentoxide (P2O5) as well as the matrix, and can additionally be modified by adding a metal ion which can be selected from the group consisting of fluorine (F), copper (Cu), lithium (Li), or other, without being restricted to these mentioned elements.
  • a metal ion which can be selected from the group consisting of fluorine (F), copper (Cu), lithium (Li), or other, without being restricted to these mentioned elements.
  • the nanoparticles of the present invention are modified with fluorine, obtaining a final molar composition corresponding to 58SiO 2 : 40CaO: 5P 2 Os: F, called bioactive glass gel with fluorinated bioactive glass nanoparticles (nVBF Gel) .
  • the mixture of these bioactive nano-particles with fluorine with the bioactive matrix enhances the activity of the composition, repairing incipient caries lesions in a few days.
  • the nano-particles are modified with Cu, in addition to the repairing properties an antibacterial effect is obtained, whereas if the nano-particles are modified with Li, superior odontogenic properties are obtained to the unmodified nano-particles.
  • the composition comprises between 97.5-99.5% matrix and 0.5-2.5% nanoparticles, more preferably it comprises between 97.5-99.5% of matrix with molar composition corresponding to 58Ca0: 36Si0 2 : 6P 2 0s and 0.5-2, 5% of nanoparticles of molar composition corresponding to 58SiO 2 : 40CaO: 5P 2 Os: F, and even more preferably it comprises 98 , 5-99.0% of matrix with molar composition corresponding to 58Ca0: 36Si02: 6P20s and 1, 0-1.5% of nanoparticles of molar composition corresponding to
  • any person with average knowledge in the state of the art can infer that the matrix / nanoparticle ranges can vary, without being restricted to the values previously described.
  • a second object of the invention is a method for the preparation of the composition for the repair of incipient dental caries, comprising the steps of preparing nano-particles that include silicon, calcium and phosphate ions by the sol-gel method, adding said nanoparticles to a precursor solution of a matrix that includes ions of silicon, calcium and phosphate, and allow the previous mixture to gel, until obtaining the composition for the repair of incipient dental caries.
  • prepare synonymous with obtaining, manufacturing or synthesizing the matrix, the nano-particle or its mixture, in its broadest conception.
  • the solution of calcium nitrate (Ca (N03) 2 '3H 2 0) in water has a concentration of between 6.0-7.0% w / v
  • the solution of ammonium phosphate dihydrogen (NH4H2PO4) in water has a concentration of between 0.10-0.20% w / v
  • the solution of ammonium fluoride (NH4F) in water has a concentration between 0.01-0.05% w / v .
  • the pH is simultaneously adjusted between 10 and 11, which results in the formation of a suspension containing the nano-particles.
  • This suspension is kept under stirring for 48 hours at 30 ° C, and then it is kept at rest or decanted for 24 hours at room temperature to obtain a precipitate with nanoparticles.
  • This precipitate is purified by cycles of centrifugation / re-dispersion in water at 12,000 rpm, a process that also allows the separation of the nanoparticles from each other. Finally, the purified nano-particles are calcined at 700 ° C for 3 hours to obtain a fine white powder.
  • the precursor solution of a matrix is prepared by the steps of hydrolyzing tetraethylortisolicate Si (OC2Fl5) 4 in acidified 95% ethanol, and adding triethylphosphate (C 2 Fl 5 ) 3P0 4 (> 99%) and Ca (N03) 2 '3H 2 0 to form the precursor solution of the matrix.
  • tetraethylortisolicate Si (OC2H5) 4 in ethanol has a concentration of between 27-29% v / v, the concentration of triethylphosphate (C 2 Fl 5 ) 3P0 4 (> 99%) in the precursor solution it is between 2.0-2.3% v / v, and because the concentration of Ca (N03) 2 '3H 2 0 in the precursor solution is between 3.0-3.5% w / v.
  • the amount of nano-particles added to the matrix precursor solution depends on the final concentration desired: gels with nano-particle content between 0.5 and 2.5% by weight.
  • the mass of nano-particles that is added to the mixture to obtain a certain content (%) of nanoparticle is given by the following expression:
  • Nanoparticle mass (mg) - - Where the "nanoparticle mass” is obtained considering that the evaporation of the 44.8 mL ethanol from the sol (or gel) generates a film mass of 0.2 g.
  • Example 1 Synthesis of the composition for incipient dental repair.
  • a bioactive glass gel (VB) with a molar composition 58Ca0: 36Si0 2 : 6P 2 0s was first prepared.
  • a solution of 4mL of tetraethylorthosilicate Si (OC2Hs) 4 (TEOS) dissolved in 10 mL of 95% ethanol (EtOH) was prepared with 0.5 mL of 0.5N hydrochloric acid.
  • the solution was maintained in magnetic stirring for 20 minutes at room temperature.
  • 0.32 mL of triethylphosphate (TEP) (C 2 H 5 ) 3P0 4 (> 99%) and 0,49 g of Ca (N0 3 ) 2 * 3H 2 0 were added.
  • the resulting mixture was kept in agitation for 3 hours at room temperature.
  • the fluorinated bioactive glass nanoparticles (nVBF) with molar composition was prepared 58 SiO2: 40CaO: 5P 2 Os: F.
  • a solution was prepared in which 7.7 g of calcium nitrate Ca (N03) 2 '3H 2 0 dissolved in 120 mL of water was added to a solution of 9.7 mL of tetraorthosilicate Si (OC2Hs) 4 (TEOS) dissolved in 95% ethanol.
  • the pH of the resulting mixture was adjusted between 1 and 2 with 0.5 N HCl.
  • This mixture was added to a solution with 2.1 g of ammonium dihydrogen phosphate NH4H2PO4 and 0.4 g of NH4F ammonium fluoride dissolved in 1500 mL of distilled water, while simultaneously aqueous ammonia NH4OH was added to maintain the pH between 10 and 1 1 and produce the formation of a precipitate.
  • the suspension that was obtained was kept under stirring for 48 hours at 30 ° C and then decanted for 24 hours at room temperature.
  • the nano-particles that were produced were separated and purified by centrifugation / re-dispersion cycles in water at 12,000 rpm.
  • the solid obtained was calcined at 700 ° C for 3 hours to obtain a fine white powder.
  • nVBF fluorinated bioactive glass gel with fluorinated bioactive glass nanoparticles
  • the prepared teeth were immersed in a demineralising solution of acetic acid (50 mM CH3COOH, 2.2 mM KH 2 PO 4, 2.2 mM CaC ⁇ FhO, pH 4.4 adjusted with KOH) under stirring at room temperature for 5 days. The solution was renewed every 24 hours.
  • acetic acid 50 mM CH3COOH, 2.2 mM KH 2 PO 4, 2.2 mM CaC ⁇ FhO, pH 4.4 adjusted with KOH
  • Example 3 Application of treatments on LMB The samples of LMB were divided into the following experimental groups: Control (LMB without treatment), BF (LMB with application of fluoride varnish, Duraphat ® ), VB Gel (LMB with VB gel application) without nano-particles) and nVBF Gel (LMB with application of gel composition + 1% nVBF).
  • Control LMB without treatment
  • BF LMB with application of fluoride varnish, Duraphat ®
  • VB Gel LMB with VB gel application
  • nVBF Gel LMB with application of gel composition + 1% nVBF
  • each LMB On the clean and dry surface of each LMB, a thin layer of gel was applied with microbrush according to the experimental groups previously described. After the first application, it was dried gently with compressed air for 10 seconds and a second layer was applied, repeating the drying process for another 10 seconds. The fluoride varnish was applied with a brush in a thin layer on the clean and dry surface of each LMB, according to the manufacturer's instructions.
  • FIG. 1 the microscopic state of the LMBs of the different experimental groups is shown, in frontal and transversal view, before being subjected to the bioactivity test.
  • the images were obtained with scanning electron microscopy (SEM) of: LMB without treatment (Control, FIG.1A); Fluorine varnish on LMB (BF, FIG 1B); LMB treated with VB Gel without nano-particles (Gel VB, FIG.1C) and LMB with application of gel composition + 1% nVBF (Gel nVBF, FIG.1D).
  • SEM scanning electron microscopy
  • the Control group shows an irregular mineral surface, with exposure of demineralized enamel prisms heterogeneously at different level of depth (7, 2 + 1, 9 pm).
  • the LMB with BF application completely covers the sample with a combination of sodium fluoride crystals embedded in a matrix of organic resins and variable thickness (10.8 + 2.9 p.m.).
  • the Gel VB group presented a smooth and uniform surface, forming a thin layer (6.7 ⁇ 1, 2 pm) and with little presence of mineral remains trapped in its thickness.
  • the Gel nVBF group presented a thin-film nano-porous surface (7.0 +/- 0.7 p.m.) with the occurrence of cracks, covering the entire demineralized tooth enamel.
  • Step 1 Immersion for 3 hours in demineralizing solution (50mM CH3COOH, 0.9mM KH 2 P0 4 , 0.5mM CaCl 2 : 2H 2 0, pH 4.8 adjusted with KOH), with constant agitation and at room temperature.
  • Step 2 Immersion for 2 hours in artificial saliva, with constant agitation and at room temperature.
  • Step 3 Immersion for 3 hours in demineralizing solution (50mM CH3COOH, 0.9mM KH 2 P0 4 , 0.5mM CaCl 2 : 2H 2 0, pH 4.8 adjusted with KOH), with constant agitation and at room temperature.
  • Step 4 Immersion for 16 hours in artificial saliva, with constant agitation and at room temperature.
  • FIG. 2A can be observed an LMB treated with BF, which presents an irregular and heterogeneous surface marked by the presence of corpuscles of organic / mineral material on partially covered dental enamel. The thickness is also heterogeneous (6, 5 + 2.0 pm).
  • FIG. 2B shows a LMB treated with VB Gel without nano-particles, where a uniform and thicker mineral layer (5.0 ⁇ 1, 2 pm) is observed than the Gel nVBF group.
  • FIG. 2C shows an LMB treated with nVBF Gel, where the surface is covered by a dense and thin mineral layer (3, 2 + 0, 5 pm) intimately linked with the underlying enamel.
  • FIG. 1A can be observed an LMB treated with BF, which presents an irregular and heterogeneous surface marked by the presence of corpuscles of organic / mineral material on partially covered dental enamel. The thickness is also heterogeneous (6, 5 + 2.0 pm).
  • FIG. 2B shows a LMB treated with VB Gel without nano-particles, where a uniform and thicker mineral
  • 2D shows the surface of healthy dental enamel, corresponding to a dense and continuous amorphous mineral layer, a few nanometers thick (3, 6 + 0, 3 pm), which covers the surface of the prisms of the underlying enamel.
  • the mineral phase that produces nVBF Gel is similar to that of healthy tooth enamel, being particularly denser and even when the gel contains nanoparticles.
  • FIG. 3A an infrared spectrum graph of the fluorinated varnish (BF) and the nVBF Gel is shown, before and after the bioactivity test, performed by means of an infrared spectrometer with Fourier transforms - Attenuated total reflectance (FTIR-ATR).
  • FTIR-ATR Fourier transforms - Attenuated total reflectance
  • FIG. 3B two infrared spectrum graphs are shown: the first of Gel VB and the second of Gel nVBF, before and after the bioactivity test, performed by means of an infrared spectrometer with Fourier transforms - Attenuated total reflectance (FTIR-ATR). It can be observed that the spectrum of the lesion treated with the VB Gel without nano-particles shows a partial transformation of the bioactive glass phase after 7 days of treatment, without the complete appearance of the hydroxyapatite band.
  • FTIR-ATR Fourier transforms - Attenuated total reflectance
  • nVBF Gel repairs the incipient caries lesion with a phase equivalent in structure to the original mineral component of the enamel (hydroxyapatite), and that the formation of well-crystallized apatite occurs only when the gel contains fluorinated bioactive glass nanoparticles.
  • Example 5 Acid Challenge Tests After the bioactivity test, samples of Gel VB and nVBF Gel were immersed in 200 mL of cola drink for 2 minutes (pH 2.4) and others in 200 mL of lactic acid, also for 2 minutes. minutes (pH 4.4). This test allowed to measure the stability of the mineral phase formed in conditions simulating the demineralizing action of cariogenic bacteria or dental erosion produced by the consumption of acidic beverages. As can be seen in FIG. 4 which shows SEM images of cross sections, the repairing phase / mineral layer produced by the gels, both the VB Gel and the nVBF Gel are able to withstand the demanding acid treatments.

Abstract

The present invention relates to a composition for repairing incipient tooth decay that comprises a matrix (preferably a gel) and nanoparticles included and/or dispersed in said matrix, where said matrix and said nanoparticles include silicon, calcium and phosphate ions; and a method for preparing said composition.

Description

COMPOSICIÓN PARA LA REPARACIÓN DE CARIES DENTAL INCIPIENTE Y MÉTODO DE PREPARACIÓN DE LA MISMA  COMPOSITION FOR REPAIR OF INCIPIENT DENTAL CARIES AND METHOD OF PREPARATION OF THE SAME
CAMPO TÉCNICO DE LA INVENCIÓN TECHNICAL FIELD OF THE INVENTION
La presente invención se relaciona a preparaciones de uso dental, en particular proporciona una composición para la reparación de caries dentales incipientes que comprende una matriz y nano-partículas, y un método para la preparación de dicha composición. The present invention relates to preparations for dental use, in particular it provides a composition for the repair of incipient dental caries comprising a matrix and nano-particles, and a method for the preparation of said composition.
ANTECEDENTES DE LA INVENCIÓN BACKGROUND OF THE INVENTION
La caries dental es una enfermedad de alta prevalencia en el mundo, cuya prevención y tratamiento se compone de un conjunto variado de prácticas clínicas y sociales. La caries dental resulta de un proceso de desmineralización del tejido duro dentario constituido por la fase mineral hidroxiapatita, debido a la acción de los ácidos orgánicos generados producto del metabolismo de fermentación de los carbohidratos llevado a cabo por las bacterias adheridas a la superficie dentaria (R.H Selwitz, A.l. Ismail, N.B. Pitts. Dental caries. Lancet. 369, 51 , 2007). Si esta biopelícula no es removida de la superficie dentaria, el proceso de desmineralización progresa en el tiempo, produciendo una lesión inicial de caries no-cavitada conocida como lesión de mancha blanca (LMB), caries temprana o incipiente, que se manifiesta como una pérdida de translucidez del esmalte, la presencia de una superficie opaca y sin brillo; y que a micro y nano-escala se caracteriza por el aumento de la microporosidad y de los espacios entre los cristales de hidroxiapatita. A medida que la biopelícula continúa madurando sobre una caries incipiente, el grado de desmineralización progresa, produciéndose la cavitación de la lesión. Dental caries is a disease of high prevalence in the world, whose prevention and treatment is composed of a varied set of clinical and social practices. Dental caries results from a demineralization process of the hard dental tissue constituted by the hydroxyapatite mineral phase, due to the action of the organic acids generated as a result of the fermentation metabolism of the carbohydrates carried out by the bacteria adhered to the tooth surface (RH Selwitz, Al Ismail, NB Pitts, Dental Caries, Lancet, 369, 51, 2007). If this biofilm is not removed from the tooth surface, the demineralization process progresses over time, producing an initial non-cavitated caries lesion known as a white spot lesion (LMB), early or incipient caries, which manifests as a loss of translucency of the enamel, the presence of an opaque and dull surface; and that at the micro and nano-scale is characterized by the increase of the microporosity and the spaces between the hydroxyapatite crystals. As the biofilm continues to mature on an incipient caries, the degree of demineralization progresses, resulting in the cavitation of the lesion.
Las observaciones clínicas sugieren que la lesión de caries se puede detener en cualquiera de los estados de su desarrollo, mientras no exista cavitación (E. Kidd. The implications of the new paradigm of dental caries. J Dent. 39 Suppl 2,3, 201 1 ). Por tanto, si la superficie del diente se encuentra intacta, las lesiones de caries detectadas clínica o radiográficamente no necesitan un tratamiento restaurador, sino medidas preventivas que persigan devolver el equilibrio perdido, preservando al máximo el tejido dentario original, idealmente evitando que se produzca la enfermedad o interceptando su progreso con la menor pérdida de tejido duro posible. Clinical observations suggest that the caries lesion can be stopped in any of the stages of its development, as long as there is no cavitation (E. Kidd, The implications of the new paradigm of dental caries, J Dent, 39 Suppl 2,3, 201 one ). Therefore, if the surface of the tooth is intact, caries lesions detected clinically or radiographically do not need a restorative treatment, but preventive measures that seek to restore the lost balance, preserving to the maximum the original dental tissue, ideally preventing the disease from occurring or intercepting its progress with the least possible loss of hard tissue.
En este sentido, actualmente existe un mayor énfasis en desarrollar tecnologías de remineralización orientadas al tratamiento de las lesiones cariosas en etapas tempranas. El producto odontológico más tradicional orientado al control de caries incipientes es el barniz fluorado, el cual consiste en una matriz de resina natural con altos contenidos de ion fluoruro. Aunque el efecto de la fluorterapia en desacelerar la desmineralización o promover algún grado de remineralización se ha observado a través de trabajos in vitro e in vivo (J.D.B Featherstone. Clinical aspects of de/remineralization of teeth. Adv Dent Res. 49, 175, 1995), el mecanismo presenta limitaciones: no existe evidencia que la terapia con fluoruro conduzca a la efectiva formación de fluorapatita, sino que permite que el tejido ya existente sea más insoluble y presente mejores propiedades mecánicas. Más recientemente, se desarrolló el producto comercial ICON®, a base de una resina de baja viscosidad fotopolimerizable denominado“infiltrante”, debido a que la resina“infiltra” el tejido dental afectado sin necesidad de la apertura mecánica de una cavidad. Este infiltrante presenta evidencia clínica en reducir el avance de lesiones tempranas (M.B. Altarabulsi, M. Alkilzy, M. Petrou, C. Splieth, Clinical safety, quality and effect of resin infiltration for proximal caries. Eur J Paediatr Dent. 15, 39, 2014), creando una barrera de difusión entre la superficie dental y la acción desmineralizadora del medio. Sin embargo, ICON® es una resina acrílica que no presenta componentes bioactivos, y, por lo tanto, no posee la capacidad para estimular el proceso de remineralización y reparación de la lesión. In this sense, there is currently a greater emphasis on developing remineralization technologies aimed at the treatment of carious lesions in the early stages. The most traditional odontological product aimed at the control of incipient caries is the fluoride varnish, which consists of a natural resin matrix with high contents of fluoride ion. Although the effect of flurterapy in slowing demineralization or promoting some degree of remineralization has been observed through in vitro and in vivo studies (JDB Featherstone, Clinical aspects of de / remineralization of teeth, Adv Dent Res. 49, 175, 1995 ), the mechanism has limitations: there is no evidence that fluoride therapy leads to the effective formation of fluorapatite, but that the existing tissue is more insoluble and has better mechanical properties. More recently, the ICON ® commercial product was developed, based on a low-viscosity, light-curing resin called "infiltrant", because the resin "infiltrates" the affected dental tissue without the need for mechanical opening of a cavity. This infiltrant presents clinical evidence to reduce the advance of early lesions (MB Altarabulsi, M. Alkilzy, M. Petrou, C. Splieth, Clinical safety, quality and effect of resin infiltration for proximal caries.) Eur J Paediatr Dent. 15, 39, 2014), creating a diffusion barrier between the tooth surface and the demineralizing action of the medium. However, ICON ® is an acrylic resin that has no bioactive components, and, therefore, does not have the ability to stimulate the process of remineralization and repair of the injury.
Un producto conocido en el estado de la técnica como agente remineralizante es el material biocerámico denominado vidrio bioactivo (VB), conocido por su capacidad para estimular la cristalización de hidroxiapatita, promover la actividad osteogénica de las células formadoras de tejido óseo y presentar cierto grado de actividad antimicrobiana (J.R. Jones. Review of bioactive glass: from Hench to hybrids. Acta Biomater. 9, 4427, 2013). Debido a su comprobada capacidad para formar hidroxiapatita cristalina en contacto con los medios fisiológicos, este material de composición típica 45%Si02 - 24,5% Na2Ü - 24,5% CaO - 6% P2O5 se utiliza como agente activo remineralizante en algunos productos dentales, principalmente orientados a resolver el problema de la sensibilidad dentaria. El vidrio bioactivo utilizado en productos de aplicación odontológica comercial está en forma de micropartícula (~ 12 pm) y bajo el nombre de la tecnología Novamin®. Si bien las investigaciones muestran que el vidrio bioactivo es un potencial agente remineralizador para lesiones no cavitadas, las formulaciones realizadas hasta la fecha comprenden una pasta comercial con VB micrométrico o polvo de VB suspendido en agua, lo cual no permite una acción prolongada semejante al barniz fluorado o a la resina infiltrante ICON®. Si bien existen estudios de matrices poliméricas con nano-partículas de VB, éstos están orientados a la regeneración de tejido óseo, por lo que la composición es más compleja y combina la bioactividad de las partículas inorgánicas con las propiedades de soporte de una matriz polimérica tridimensional, que permite promover la unión celular, el crecimiento y la deposición mineral para la formación de nuevo tejido óseo (F. Valenzuela, C. Covarrubias, C. Martínez, P. Smith, M. Síaz-Dosque, M. Yazdani-Pedram. Preparation and bioactive properties of novel bone-repair bionanocomposites on hydroxiapatite and bioactive glass nanoparticles. J Biomed Mater Res B Appl Biomater. 100(6), 1672-82, 2012), es decir, no son formulaciones que puedan ser aplicadas en clínica dental para la reparación de caries dental incipiente. A product known in the state of the art as a remineralizing agent is the bioceramic material called bioactive glass (VB), known for its ability to stimulate the crystallization of hydroxyapatite, promote the osteogenic activity of bone tissue forming cells and present a certain degree of antimicrobial activity (JR Jones, Review of bioactive glass: from Hench to hybrids, Biomater Act, 9, 4427, 2013). Due to its proven ability to form crystalline hydroxyapatite in contact with physiological media, this material of typical composition 45% Si0 2 - 24.5% Na2Ü - 24.5% CaO - 6% P 2 O 5 is used as active remineralizing agent in some dental products, mainly aimed at solving the problem of tooth sensitivity. The bioactive glass used in commercial dental application products is in the form of a microparticle (~ 12 pm) and under the name of Novamin ® technology. Although research shows that bioactive glass is a potential remineralizing agent for non-cavitated lesions, the formulations made up to date comprise a commercial paste with micrometric VB or VB powder suspended in water, which does not allow a prolonged action similar to varnish fluoride or ICON ® infiltrating resin. Although there are studies of polymer matrices with VB nanoparticles, these are oriented to the regeneration of bone tissue, so the composition is more complex and combines the bioactivity of the inorganic particles with the support properties of a three-dimensional polymer matrix. , which allows to promote cell attachment, growth and mineral deposition for the formation of new bone tissue (F. Valenzuela, C. Covarrubias, C. Martinez, P. Smith, M. Siaz-Dosque, M. Yazdani-Pedram. Preparation and bioactive properties of new bone-repair bionanocomposites on hydroxyapatite and bioactive glass nanoparticles J Biomed Mater Res B Appl Biomater 100 (6), 1672-82, 2012), that is, they are not formulations that can be applied in dental clinic for the repair of incipient dental caries.
SUMARIO DE LA INVENCIÓN SUMMARY OF THE INVENTION
Un primer objeto de la invención es una composición para la reparación de caries dental incipiente que comprende una matriz y nano-partículas incluidas dicha matriz, caracterizada porque dicha matriz y dichas nanopartículas incluyen iones de silicio, calcio y fosfato, donde preferentemente dicha matriz es un gel. A first object of the invention is a composition for the repair of incipient dental caries comprising a matrix and nano-particles including said matrix, characterized in that said matrix and said nanoparticles include silicon, calcium and phosphate ions, wherein preferably said matrix is a gel.
En una modalidad preferida, dicha matriz y las nano-partículas comprenden dióxido de silicio (S1O2), óxido de calcio (CaO) y pentóxido de fósforo (P2O5). Más particularmente, las nano-partículas comprenden adicionalmente flúor (F). En otra modalidad preferida, la matriz tiene una composición molar correspondiente a 58Ca0:36Si02:6P205, y la nano-partícula tiene una composición molar correspondiente a 58SiO2:40CaO:5P2Os:F. In a preferred embodiment, said matrix and the nanoparticles comprise silicon dioxide (S1O2), calcium oxide (CaO) and phosphorus pentoxide (P2O5). More particularly, the nano-particles additionally comprise fluorine (F). In another preferred embodiment, the matrix has a molar composition corresponding to 58Ca0: 36Si02: 6P205, and the nanoparticle has a molar composition corresponding to 58SiO 2 : 40CaO: 5P 2 Os: F.
Preferentemente, la composición comprende entre 97,5-99,5% de matriz y 0,5- 2,5% de nano-partículas, más preferentemente comprende entre 97,5-99,5% de matriz con composición molar correspondiente a 58Ca0:36Si02:6P20s y 0,5-2, 5% de nano-partículas de composición molar correspondiente a 58SiO2:40CaO:5P2O5:F. Preferably, the composition comprises between 97.5-99.5% matrix and 0.5-2.5% nanoparticles, more preferably it comprises between 97.5-99.5% matrix with molar composition corresponding to 58Ca0 : 36Si0 2 : 6P 2 0s and 0.5-2.5% nanoparticles of molar composition corresponding to 58SiO 2 : 40CaO: 5P 2 O 5 : F.
Un segundo objeto de la invención es un método para la preparación de una composición para la reparación de caries dental incipiente, que comprende los pasos de: A second object of the invention is a method for the preparation of a composition for the repair of incipient dental caries, comprising the steps of:
- preparar nano-partículas que incluyen iones de silicio, calcio y fosfato mediante el método sol-gel; - prepare nano-particles that include silicon, calcium and phosphate ions by the sol-gel method;
- añadir dichas nano-partículas a una solución precursora de una matriz que incluye iones de silicio, calcio y fosfato; y - adding said nano-particles to a precursor solution of a matrix that includes silicon, calcium and phosphate ions; Y
- permitir gelificar la mezcla anterior, hasta obtener la composición. Particularmente, las nano-partículas se preparan mediante los pasos de: - allowing the above mixture to gel, until the composition is obtained. Particularly, the nano-particles are prepared by the steps of:
- agregar nitrato de calcio (Ca(N03)2‘3Fl20) disuelto en agua a una solución con tetraortosilicato en etanol 95% para formar una primera mezcla; - ajustar el pH de la primera mezcla entre 1 y 2; - add calcium nitrate (Ca (N03) 2 '3Fl 2 0) dissolved in water to a solution with tetraorthosilicate in 95% ethanol to form a first mixture; - adjust the pH of the first mixture between 1 and 2;
- agregar a la primera mezcla una solución de dihidrógeno de fosfato de amonio (NH4H2P04) y fluoruro de amonio (NH4F) en agua para formar una segunda mezcla; - adding to the first mixture a solution of ammonium phosphate dihydrogen (NH 4 H 2 P0 4 ) and ammonium fluoride (NH 4 F) in water to form a second mixture;
- ajustar el pH de la segunda mezcla entre 10 y 11 ; - adjust the pH of the second mixture between 10 and 11;
- agitar la mezcla obtenida del paso anterior; y - mantener en reposo la segunda mezcla para obtener un precipitado que contiene las nano-partículas. - stirring the mixture obtained from the previous step; Y - keeping the second mixture at rest to obtain a precipitate containing the nanoparticles.
En una realización preferida, la solución de nitrato de calcio (Ca(N03)2‘3H20) en agua posee una concentración de entre 6, 0-7,0% p/v, la solución de dihidrógeno de fosfato de amonio (NH4H2PO4) en agua posee una concentración de entre 0,10- 0,20% p/v, la solución de fluoruro de amonio (NH4F) en agua posee una concentración de entre 0,01-0,05% p/v. In a preferred embodiment, the solution of calcium nitrate (Ca (N03) 2 '3H 2 0) in water has a concentration of between 6.0-7.0% w / v, the dihydrogen solution of ammonium phosphate ( NH4H2PO4) in water has a concentration between 0.10-0.20% w / v, the solution of ammonium fluoride (NH4F) in water has a concentration between 0.01-0.05% w / v.
Preferentemente, luego de ajustar el pH de la segunda mezcla, ésta se agita por 48 horas a 30°C. Adicionalmente, el precipitado con las nano-partículas se purifica mediante centrifugación/re-dispersión en agua a 12.000 rpm, y luego se liofilizan y se calcinan a 700°C por 3 horas. Preferably, after adjusting the pH of the second mixture, it is stirred for 48 hours at 30 ° C. Additionally, the precipitate with the nano-particles is purified by centrifugation / re-dispersion in water at 12,000 rpm, and then lyophilized and calcined at 700 ° C for 3 hours.
En otra realización preferida, la solución precursora de una matriz se prepara mediante los pasos de: - hidrolizar tetraetilortisolicato Si(OC2Hs)4 en etanol 95% acidificado; y In another preferred embodiment, the precursor solution of a matrix is prepared by the steps of: hydrolyzing tetraethylortisolicate Si (OC2Hs) 4 in 95% acidified ethanol; Y
- agregar trietilfosfato (C2Hs)3P04 (>99%) y de Ca(N03)2‘3H20 para formar la solución precursora de la matriz. - add triethylphosphate (C 2 Hs) 3P0 4 (> 99%) and Ca (N03) 2 '3H 2 0 to form the parent precursor solution.
Preferentemente, el tetraetilortisolicato Si(OC2Hs)4 en etanol posee una concentración entre 27-29% v/v, la concentración de trietilfosfato (C2Hs)3P04 (>99%) en la solución precursora es entre 2, 0-2, 3% v/v, y la concentración dePreferably, the tetraethylortisolicate Si (OC2Hs) 4 in ethanol has a concentration between 27-29% v / v, the concentration of triethylphosphate (C 2 Hs) 3P0 4 (> 99%) in the precursor solution is between 2.0-2. , 3% v / v, and the concentration of
Ca(N03)2‘3H20 en la solución precursora es de entre 3, 0-3, 5% p/v. Ca (N03) 2 '3H 2 0 in the precursor solution is between 3.0-3.5% w / v.
BREVE DESCRIPCIÓN DE LAS FIGURAS BRIEF DESCRIPTION OF THE FIGURES
Las FIG. 1 muestra imágenes de microscopía electrónica de barrido SEM de muestras antes de someterse a ensayos de bioactividad. (FIG. 1A) control; (FIG. 1 B) barniz de flúor sobre lesiones de mancha blanca; (FIG. 1C) gel de vidrio bioactivo sin nano-partículas sobre lesiones de mancha blanca; (FIG. 1 D) gel de vidrio bioactivo con 1 % de nano-partículas de vidrio bioactivo fluorado sobre lesiones de mancha blanca. Las FIG. 2 muestra imágenes de microscopía electrónica de barrido SEM de muestras después de someterse a ensayos de bioactividad. (FIG. 2A) barniz de flúor sobre lesiones de mancha blanca; (FIG. 2B) gel de vidrio bioactivo sin nano- partículas sobre lesiones de mancha blanca; (FIG. 2C) gel de vidrio bioactivo con 1 % de nano-partículas de vidrio bioactivo fluorado sobre lesiones de mancha blanca; (FIG. 2D) esmalte dental sano. FIG. 1 shows electron microscopy images of SEM scanning of samples before being subjected to bioactivity assays. (FIG 1A) control; (FIG 1B) Fluoride varnish on white spot lesions; (FIG 1C) bioactive glass gel without nano-particles on white spot lesions; (FIG.1D) bioactive glass gel with 1% fluorinated bioactive glass nanoparticles on white spot lesions. FIG. 2 shows electron microscopy images of SEM scanning of samples after undergoing bioactivity assays. (FIG 2A) Fluoride varnish on white spot lesions; (FIG 2B) bioactive glass gel without nanoparticles on white spot lesions; (FIG 2C) bioactive glass gel with 1% fluorinated bioactive glass nanoparticles on white spot lesions; (FIG 2D) healthy tooth enamel.
Las FIG. 3 muestran gráficos de espectro infrarrojo de muestras antes y después de someterse a ensayos de bioactividad. (FIG. 3A) muestras tratadas con barniz de flúor; (FIG. 3B) muestras tratadas con gel de vidrio bioactivo; (FIG. 3C) muestras tratadas con gel de vidrio bioactivo con 1 % de nano-partículas de vidrio bioactivo fluorado. FIG. 3 show infrared spectrum graphs of samples before and after undergoing bioactivity assays. (FIG 3A) samples treated with fluoride varnish; (FIG 3B) samples treated with bioactive glass gel; (FIG 3C) samples treated with bioactive glass gel with 1% fluorinated bioactive glass nanoparticles.
La FIG. 4 muestra imágenes de microscopía electrónica de barrido SEM de muestras tratadas con gel de vidrio bioactivo y gel de vidrio bioactivo con 1 % de nano-partículas de vidrio bioactivo fluorado después de someterse a ensayos de desafío con ácidos. FIG. 4 shows SEM scanning electron microscopy images of samples treated with bioactive glass gel and bioactive glass gel with 1% fluorinated bioactive glass nanoparticles after being subjected to acid challenge tests.
DESCRIPCIÓN DETALLADA DE LA INVENCIÓN DETAILED DESCRIPTION OF THE INVENTION
La presente invención se refiere a una composición para la reparación de caries dental incipiente, que comprende una matriz (preferentemente un gel) y nano- partículas, ambos biológicamente activos, que al estar mezclados potencia sorprendentemente la bioactividad de la composición. The present invention relates to a composition for the repair of incipient dental caries, comprising a matrix (preferably a gel) and nanoparticles, both biologically active, which, when mixed, surprisingly potentiate the bioactivity of the composition.
En particular, tanto la matriz como las nano-partículas comprenden iones de silicio, calcio y fosfato que permiten remineralizar la lesión de caries incipiente mediante la formación de una fase mineral equivalente a la hidroxiapatita del esmalte original. El producto descrito en la presente invención es completamente novedoso, pues en el estado de la técnica hasta la fecha no se conoce una composición que tanto la matriz como las nano-partículas que incluye tengan los mismos elementos químicos (iones de silicio, calcio y fosfato). In particular, both the matrix and the nano-particles comprise silicon, calcium and phosphate ions that allow remineralization of the incipient caries lesion by forming a mineral phase equivalent to the hydroxyapatite of the original enamel. The product described in the present invention is completely novel, because in the state of the art to date there is no known composition that both the matrix and the nano-particles that it includes have the same chemical elements (silicon, calcium and phosphate ions). ).
A su vez, la presente invención también se refiere a un método de preparación de dicha composición, que comprende mezclar la matriz y las nano-partículas previamente preparadas, preferentemente en una proporción entre 97,5-99,5% de la matriz y 0,5-2, 5% de las nano-partículas, más preferentemente entre 98,5-99,0% de la matriz y 1 ,0-1 , 5% de las nano-partículas, sin limitarse a dichas proporciones. In turn, the present invention also relates to a method of preparing said composition, which comprises mixing the matrix and the previously prepared nanoparticles, preferably in a proportion between 97.5-99.5% of the matrix and 0.5-2.5% of the nanoparticles, more preferably between 98.5-99.0% of the matrix and 1.0-1.5% of the nanoparticles, without being limited to said proportions.
Todos los términos técnicos y científicos utilizados para describir la presente invención tienen el mismo significado entendido para una persona con conocimientos medios en el campo técnico en cuestión. No obstante, para definir con más claridad el alcance de la invención, a continuación, se incluye una lista de la terminología utilizada en esta descripción. All the technical and scientific terms used to describe the present invention have the same meaning understood for a person with average knowledge in the technical field in question. However, in order to define more clearly the scope of the invention, a list of the terminology used in this description is included below.
Se debe entender por“caries”, una patología dental causada por la acción de microorganismos adheridos al diente a través de una biopelícula, los que en presencia de azúcares fermentables de la dieta generan ácidos que difunden en la interfase entre la biopelícula dental y el tejido duro del diente. Esto produce una desmineralización, inicialmente sub-superficial, progresiva del diente que puede provocar cavidades que alcanzan a los tejidos profundos del diente. It must be understood by "caries", a dental pathology caused by the action of microorganisms adhered to the tooth through a biofilm, which in the presence of fermentable sugars in the diet generate acids that diffuse at the interface between the dental biofilm and the tissue hard of the tooth. This produces a demineralization, initially sub-superficial, progressive of the tooth that can cause cavities that reach the deep tissues of the tooth.
Se debe entender por“caries incipiente” o“lesión de mancha blanca” (LMB), una lesión inicial de caries no-cavitada que se manifiesta como una pérdida de translucidez del esmalte, la presencia de una superficie opaca y sin brillo, y que a micro y nano-escala se caracteriza por el aumento de la microporosidad y de los espacios entre cristales de hidroxiapatita. It should be understood as "incipient caries" or "white spot lesion" (LMB), an initial non-cavitated caries lesion that manifests as a loss of translucency of the enamel, the presence of an opaque and dull surface, and that a micro and nano-scale is characterized by the increase of microporosity and the spaces between hydroxyapatite crystals.
Se debe entender por“gel”, una intrincada red de partículas unidas entre sí con espacio suficiente entre ellas para atrapar moléculas de agua y otros compuestos en su estructura tridimensional, que forma un semi-sólido con dos fases: una fase sólida y una líquida. En este caso en particular, el gel no sólo cumple la función de soporte estructural, sino que también es biológicamente activo. It should be understood by "gel", an intricate network of particles joined together with enough space between them to trap water molecules and other compounds in its three-dimensional structure, which forms a semi-solid with two phases: a solid phase and a liquid . In this particular case, the gel not only fulfills the function of structural support, but is also biologically active.
Se debe entender por“nano-partícula”, una partícula que posee una dimensión menor que 100 nm, que se comporta como una unidad completa con respecto a sus propiedades fisicoquímicas. It should be understood by "nano-particle", a particle that has a dimension less than 100 nm, which behaves as a complete unit with respect to its physicochemical properties.
Se debe entender por“bioactivo” o con “actividad biológica”, un material que proporciona una respuesta biológica apropiada y resulta en la formación de una unión entre el material y el tejido donde se aplica. En particular, una“cerámica bioactiva” es aquella que forma hidroxiapatita biológicamente activa a través de reacciones químicas de su superficie con los fluidos líquidos circundantes. It should be understood by "bioactive" or "biological activity", a material that provides an appropriate biological response and results in the formation of a bond between the material and the tissue where it is applied. In particular, a "ceramic bioactive "is one that forms biologically active hydroxyapatite through chemical reactions of its surface with the surrounding liquid fluids.
Se debe entender por“vidrio bioactivo” (VB), un material de vidrio-cerámica con actividad biológica cuya composición contiene principalmente S1O2, CaO y P2O5. Puede contener adicionalmente Na2Ü o elementos minerales tales como Cu, Li, F, etc. It should be understood by "bioactive glass" (VB), a glass-ceramic material with biological activity whose composition contains mainly S1O 2 , CaO and P 2 O 5 . It may additionally contain Na2Ü or mineral elements such as Cu, Li, F, etc.
Un primer objeto de la presente invención se refiere a una composición para la reparación de caries dental incipiente, que comprende una matriz y nano-partículas incluidas y/o dispersas en dicha matriz, donde dicha matriz y dichas nano-partículas incluyen iones de silicio, calcio y fosfato. A first object of the present invention relates to a composition for the repair of incipient dental caries, comprising a matrix and nano-particles included and / or dispersed in said matrix, wherein said matrix and said nano-particles include silicon ions, calcium and phosphate.
En una modalidad preferida, la matriz es un gel que comprende dióxido de silicio (S1O2), óxido de calcio (CaO) y pentóxido de fósforo (P2O5), preferentemente en una composición molar correspondiente a 58Ca0:36Si02:6P20s. En esta realización particular, dicha matriz es vidrio bioactivo (VB) en gel. In a preferred embodiment, the matrix is a gel comprising silicon dioxide (S1O2), calcium oxide (CaO) and phosphorus pentoxide (P2O5), preferably in a molar composition corresponding to 58Ca0: 36Si02: 6P20s. In this particular embodiment, said matrix is bioactive glass (VB) in gel.
En una modalidad preferida, las nano-partículas también comprenden dióxido de silicio (S1O2), óxido de calcio (CaO) y pentóxido de fósforo (P2O5) al igual que la matriz, y adicionalmente se puede modificar agregando un ion metálico que puede seleccionarse del grupo que consiste de flúor (F), cobre (Cu), litio (Li), u otro, sin restringirse a estos elementos mencionados. Preferentemente, las nano-partículas de la presente invención están modificadas con flúor, obteniendo una composición molar final correspondiente a 58SiO2:40CaO:5P2Os:F, denominado gel de vidrio bioactivo con nano-partículas de vidrio bioactivo fluorado (Gel nVBF). La mezcla de estas nano-partículas bioactivas con flúor con la matriz bioactiva potencia la actividad de la composición, reparando las lesiones de caries incipientes en pocos días. Por otra parte, si las nano-partículas se modifican con Cu, además de las propiedades reparadoras se obtiene un efecto antibacteriano, mientras que si las nano-partículas se modifican con Li, se obtiene propiedades odontogénicas superiores a las nano-partículas sin modificar. In a preferred embodiment, the nano-particles also comprise silicon dioxide (S1O2), calcium oxide (CaO) and phosphorus pentoxide (P2O5) as well as the matrix, and can additionally be modified by adding a metal ion which can be selected from the group consisting of fluorine (F), copper (Cu), lithium (Li), or other, without being restricted to these mentioned elements. Preferably, the nanoparticles of the present invention are modified with fluorine, obtaining a final molar composition corresponding to 58SiO 2 : 40CaO: 5P 2 Os: F, called bioactive glass gel with fluorinated bioactive glass nanoparticles (nVBF Gel) . The mixture of these bioactive nano-particles with fluorine with the bioactive matrix enhances the activity of the composition, repairing incipient caries lesions in a few days. On the other hand, if the nano-particles are modified with Cu, in addition to the repairing properties an antibacterial effect is obtained, whereas if the nano-particles are modified with Li, superior odontogenic properties are obtained to the unmodified nano-particles.
Preferentemente, la composición comprende entre 97,5-99,5% de matriz y 0,5- 2,5% de nano-partículas, más preferentemente comprende entre 97,5-99,5% de matriz con composición molar correspondiente a 58Ca0:36Si02:6P20s y 0,5-2, 5% de nano-partículas de composición molar correspondiente a 58SiO2:40CaO:5P2Os:F, y aún más preferentemente comprende entre 98,5-99,0% de matriz con composición molar correspondiente a 58Ca0:36Si02:6P20s y 1 ,0- 1 ,5% de nano-partículas de composición molar correspondiente aPreferably, the composition comprises between 97.5-99.5% matrix and 0.5-2.5% nanoparticles, more preferably it comprises between 97.5-99.5% of matrix with molar composition corresponding to 58Ca0: 36Si0 2 : 6P 2 0s and 0.5-2, 5% of nanoparticles of molar composition corresponding to 58SiO 2 : 40CaO: 5P 2 Os: F, and even more preferably it comprises 98 , 5-99.0% of matrix with molar composition corresponding to 58Ca0: 36Si02: 6P20s and 1, 0-1.5% of nanoparticles of molar composition corresponding to
58SiO2:40CaO:5P2O5:F. Sin embargo, cualquier persona con conocimientos medios en el estado de la técnica puede inferir que los rangos de matriz/nano- partícula pueden variar, sin restringirse a los valores previamente descritos. 58SiO2: 40CaO: 5P2O5: F. However, any person with average knowledge in the state of the art can infer that the matrix / nanoparticle ranges can vary, without being restricted to the values previously described.
En la Tabla 1 , se muestra un análisis comparativo entre una modalidad preferida de la invención (gel de vidrio bioactivo con nano-partículas de vidrio bioactivo fluorado) y productos comerciales utilizados en la práctica clínica dental. In Table 1, a comparative analysis is shown between a preferred embodiment of the invention (bioactive glass gel with fluorinated bioactive glass nano-particles) and commercial products used in dental clinical practice.
Tabla 1. Comparación de modalidad de invención versus productos comerciales Table 1. Comparison of modality of invention versus commercial products
Figure imgf000010_0001
Figure imgf000011_0001
Figure imgf000010_0001
Figure imgf000011_0001
Un segundo objeto de la invención es un método para la preparación de la composición para la reparación de caries dental incipiente, que comprende los pasos de preparar nano-partículas que incluyen iones de silicio, calcio y fosfato mediante el método sol-gel, añadir dichas nano-partículas a una solución precursora de una matriz que incluye iones de silicio, calcio y fosfato, y permitir gelificar la mezcla anterior, hasta obtener la composición para la reparación de caries dental incipiente. Debe entenderse por el término“preparar”, sinónimo de obtener, fabricar o sintetizar la matriz, la nano-partícula o su mezcla, en su concepción más amplia. A second object of the invention is a method for the preparation of the composition for the repair of incipient dental caries, comprising the steps of preparing nano-particles that include silicon, calcium and phosphate ions by the sol-gel method, adding said nanoparticles to a precursor solution of a matrix that includes ions of silicon, calcium and phosphate, and allow the previous mixture to gel, until obtaining the composition for the repair of incipient dental caries. It must be understood by the term "prepare", synonymous with obtaining, manufacturing or synthesizing the matrix, the nano-particle or its mixture, in its broadest conception.
Particularmente, para preparar las nano-partículas mediante el método sol-gel se agrega nitrato de calcio (Ca(N03)2‘3H20) disuelto en agua a una solución con tetraortosilicato Si(OC2Hs)4 en etanol 95% para formar una primera mezcla; luego se ajusta el pH de la primera mezcla entre 1 y 2; después se agrega a la primera mezcla una solución de dihidrógeno de fosfato de amonio (NH4H2PO4) y fluoruro de amonio (NH4F) en agua para formar una segunda mezcla; se ajusta el pH de la segunda mezcla entre 10 y 11 ; se agita la mezcla obtenida del paso anterior; y se mantiene en reposo la segunda mezcla para obtener un precipitado que contiene las nano-partículas. En una realización particular, la solución de nitrato de calcio (Ca(N03)2‘3H20) en agua posee una concentración de entre 6, 0-7,0% p/v, la solución de de dihidrógeno de fosfato de amonio (NH4H2PO4) en agua posee una concentración de entre 0,10-0,20% p/v, la solución de de fluoruro de amonio (NH4F) en agua posee una concentración de entre 0,01-0,05% p/v. Preferentemente, cuando se agrega a la primera mezcla la solución de dihidrógeno de fosfato de amonio (NH4H2PO4) y fluoruro de amonio (NH4F) en agua, simultáneamente se ajusta el pH entre 10 y 11 , lo que produce la formación de una suspensión que contiene las nano-partículas. Esta suspensión se mantiene en agitación por 48 horas a 30°C, y luego se mantiene en reposo o se decanta por 24 horas a temperatura ambiente para obtener un precipitado con nano-partículas. Este precipitado se purifica mediante ciclos de centrifugación/re-dispersión en agua a 12.000 rpm, procedimiento que también permite la separación de las nano- partículas entre sí. Finalmente, las nano-partículas purificadas se calcinan a 700°C por 3 horas para obtener un polvo fino de color blanco. Particularly, to prepare the nano-particles by the sol-gel method calcium nitrate (Ca (N03) 2 '3H 2 0) dissolved in water is added to a solution with tetraorthosilicate Si (OC2Hs) 4 in 95% ethanol to form a first mix; then the pH of the first mixture is adjusted between 1 and 2; then a solution of ammonium phosphate dihydrogen (NH4H2PO4) and ammonium fluoride (NH4F) in water is added to the first mixture to form a second mixture; the pH of the second mixture is adjusted between 10 and 11; the mixture obtained from the previous step is stirred; and the second mixture is kept at rest to obtain a precipitate containing the nanoparticles. In a particular embodiment, the solution of calcium nitrate (Ca (N03) 2 '3H 2 0) in water has a concentration of between 6.0-7.0% w / v, the solution of ammonium phosphate dihydrogen (NH4H2PO4) in water has a concentration of between 0.10-0.20% w / v, the solution of ammonium fluoride (NH4F) in water has a concentration between 0.01-0.05% w / v . Preferably, when the solution of ammonium phosphate dihydrogen (NH4H2PO4) and ammonium fluoride (NH4F) in water is added to the first mixture, the pH is simultaneously adjusted between 10 and 11, which results in the formation of a suspension containing the nano-particles. This suspension is kept under stirring for 48 hours at 30 ° C, and then it is kept at rest or decanted for 24 hours at room temperature to obtain a precipitate with nanoparticles. This precipitate is purified by cycles of centrifugation / re-dispersion in water at 12,000 rpm, a process that also allows the separation of the nanoparticles from each other. Finally, the purified nano-particles are calcined at 700 ° C for 3 hours to obtain a fine white powder.
Particularmente, la solución precursora de una matriz se prepara mediante los pasos de hidrolizar tetraetilortisolicato Si(OC2Fl5)4 en etanol 95% acidificado, y agregar trietilfosfato (C2Fl5)3P04 (>99%) y de Ca(N03)2‘3H20 para formar la solución precursora de la matriz. En una modalidad preferida del método, el tetraetilortisolicato Si(OC2H5)4 en etanol posee una concentración de entre 27-29% v/v, la concentración de trietilfosfato (C2Fl5)3P04 (>99%) en la solución precursora es entre 2, 0-2, 3% v/v, y porque la concentración de Ca(N03)2‘3H20 en la solución precursora es de entre 3, 0-3, 5% p/v. Particularly, the precursor solution of a matrix is prepared by the steps of hydrolyzing tetraethylortisolicate Si (OC2Fl5) 4 in acidified 95% ethanol, and adding triethylphosphate (C 2 Fl 5 ) 3P0 4 (> 99%) and Ca (N03) 2 '3H 2 0 to form the precursor solution of the matrix. In a preferred embodiment of the method, tetraethylortisolicate Si (OC2H5) 4 in ethanol has a concentration of between 27-29% v / v, the concentration of triethylphosphate (C 2 Fl 5 ) 3P0 4 (> 99%) in the precursor solution it is between 2.0-2.3% v / v, and because the concentration of Ca (N03) 2 '3H 2 0 in the precursor solution is between 3.0-3.5% w / v.
Finalmente, la cantidad de nano-partículas que se agrega a la solución precursora de matriz depende de la concentración final que se desee obtener: geles con contenido de nano-partículas entre 0,5 y 2,5% en peso. La masa de nano-partículas que se agrega a la mezcla para obtener un determinado contenido (%) de nano- partícula está dada por la siguiente expresión: Finally, the amount of nano-particles added to the matrix precursor solution depends on the final concentration desired: gels with nano-particle content between 0.5 and 2.5% by weight. The mass of nano-particles that is added to the mixture to obtain a certain content (%) of nanoparticle is given by the following expression:
(% nano— partículas)x 0,2 x 1000 (% nanoparticles) x 0.2 x 1000
Masa de nano— partículas ( mg ) = - - Donde la“masa de nano-partícula” se obtiene considerando que la evaporación del etanol de 44,8 mL del sol (o gel) generan una masa de película de 0,2 g.  Nanoparticle mass (mg) = - - Where the "nanoparticle mass" is obtained considering that the evaporation of the 44.8 mL ethanol from the sol (or gel) generates a film mass of 0.2 g.
Los siguientes ejemplos están destinados a ilustrar la invención y sus modalidades preferidas, pero en ninguna circunstancia deberán considerarse para restringir el alcance de la invención, que estará definido por el tenor de las reivindicaciones que aquí se adjuntan. The following examples are intended to illustrate the invention and its preferred embodiments, but under no circumstances should they be considered to restrict the scope of the invention, which will be defined by the wording of the appended claims.
EJEMPLOS DE REALIZACIÓN EXAMPLES OF REALIZATION
Ejemplo 1. Síntesis de la composición para la reparación dental incipiente. Example 1. Synthesis of the composition for incipient dental repair.
Para la preparación de la composición, primero se preparó un gel de vidrio bioactivo (VB) con composición molar 58Ca0:36Si02:6P20s. Para ello, se preparó una solución de 4mL de tetraetilortosilicato Si(OC2Hs)4 (TEOS) disuelto en 10 mL de etanol 95% (EtOH) con 0,5 mL de ácido clorhídrico 0,5 N. Se mantuvo la solución en agitación magnética por 20 minutos a temperatura ambiente. Luego, se agregó 0,32 mL de trietilfosfato (TEP) (C2H5)3P04 (>99%) y 0,49 g de Ca(N03)2*3H20. La mezcla resultante se mantuvo en agitación por 3 horas a temperatura ambiente. For the preparation of the composition, a bioactive glass gel (VB) with a molar composition 58Ca0: 36Si0 2 : 6P 2 0s was first prepared. For this, a solution of 4mL of tetraethylorthosilicate Si (OC2Hs) 4 (TEOS) dissolved in 10 mL of 95% ethanol (EtOH) was prepared with 0.5 mL of 0.5N hydrochloric acid. The solution was maintained in magnetic stirring for 20 minutes at room temperature. Then, 0.32 mL of triethylphosphate (TEP) (C 2 H 5 ) 3P0 4 (> 99%) and 0,49 g of Ca (N0 3 ) 2 * 3H 2 0 were added. The resulting mixture was kept in agitation for 3 hours at room temperature.
Luego se preparó las nano-partículas de vidrio bioactivo fluorado (nVBF) con composición molar 58 SiO2:40CaO:5P2Os:F. Para ello, se preparó una solución en la cual se agregó 7,7 g de nitrato de calcio Ca(N03)2‘3H20 disuelto en 120 mL de agua a una solución de 9,7 mL de tetraortosilicato Si(OC2Hs)4 (TEOS) disuelto en etanol 95%. Se ajustó el pH de la mezcla resultante entre 1 y 2 con HCI 0,5 N. Se agregó dicha mezcla a una solución con 2,1 g de dihidrógeno fosfato de amonio NH4H2PO4 y 0,4 g de fluoruro de amonio NH4F disueltos en 1500 mL de agua destilada, mientras simultáneamente se agregó amoniaco acuoso NH4OH para mantener el pH entre 10 y 1 1 y producir la formación de un precipitado. La suspensión que se obtuvo se mantuvo en agitación por 48 horas a 30°C y luego se decantó por 24 horas a temperatura ambiente. Las nano-partículas que se produjeron se separaron y purificaron mediante ciclos de centrifugación/re- dispersión en agua a 12.000 rpm. El sólido que se obtuvo se calcinó a 700°C por 3h para obtener un polvo fino de color blanco. Then the fluorinated bioactive glass nanoparticles (nVBF) with molar composition was prepared 58 SiO2: 40CaO: 5P 2 Os: F. For this, a solution was prepared in which 7.7 g of calcium nitrate Ca (N03) 2 '3H 2 0 dissolved in 120 mL of water was added to a solution of 9.7 mL of tetraorthosilicate Si (OC2Hs) 4 (TEOS) dissolved in 95% ethanol. The pH of the resulting mixture was adjusted between 1 and 2 with 0.5 N HCl. This mixture was added to a solution with 2.1 g of ammonium dihydrogen phosphate NH4H2PO4 and 0.4 g of NH4F ammonium fluoride dissolved in 1500 mL of distilled water, while simultaneously aqueous ammonia NH4OH was added to maintain the pH between 10 and 1 1 and produce the formation of a precipitate. The suspension that was obtained was kept under stirring for 48 hours at 30 ° C and then decanted for 24 hours at room temperature. The nano-particles that were produced were separated and purified by centrifugation / re-dispersion cycles in water at 12,000 rpm. The solid obtained was calcined at 700 ° C for 3 hours to obtain a fine white powder.
Finalmente, se preparó una composición que contenía gel de vidrio bioactivo fluorado con nano-partículas de vidrio bioactivo fluorado (nVBF). Para ello, 4 mL de tetraetilortosilicato Si(OC2Hs)4 se hidrolizaron en 10 mL de etanol 95% acidificado con 0,5 mL de HCI 0,5 N bajo agitación magnética a temperatura ambiente por 20 min. Posteriormente se agregó 0,32 mL de tritetilfosfato (C2Hs)3P04 (>99%), 0,49 g de Ca(N03)2‘3H20 y 2 mg de nano-partículas de nVBF las que se dispersaron previamente en 30 mL de etanol 95% por 20 min en ultrasonido. La mezcla resultante de Gel con 1 % nVBF se mantuvo en agitación por 3 horas a temperatura ambiente antes de ser aplicada sobre las lesiones del esmalte. Ejemplo 2. Preparación de lesiones artificiales de caries dental incipiente o de mancha blanca (LMB). Finally, a composition containing fluorinated bioactive glass gel with fluorinated bioactive glass nanoparticles (nVBF) was prepared. For this, 4 mL of tetraethylorthosilicate Si (OC2Hs) 4 were hydrolysed in 10 mL of 95% ethanol acidified with 0.5 mL of 0.5 N HCl under magnetic stirring at room temperature for 20 min. Subsequently, 0.32 mL of tritytlphosphate (C 2 Hs) 3P0 4 (> 99%), 0.49 g was added. of Ca (N03) 2 '3H 2 0 and 2 mg of nVBF nanoparticles which were previously dispersed in 30 mL of 95% ethanol for 20 min in ultrasound. The resulting mixture of Gel with 1% nVBF was kept in agitation for 3 hours at room temperature before being applied on the enamel lesions. Example 2. Preparation of artificial lesions of incipient dental caries or white spot (LMB).
Se realizó una recolección de molares maxilares extraídos por distintas razones terapéuticas en la Clínica Odontológica de la Universidad de Chile, con previa autorización de pacientes informados verbalmente y por escrito. Se seleccionaron 15 dientes sanos: sin caries, sin obturaciones, y sin otras alteraciones estructurales del esmalte (cracks, manchas, hipoplasias, etc.). En las caras libres de los dientes seleccionados se delimitaron 4 superficies de esmalte dental de 2 mm2, todas a una distancia de 2 mm del límite amelocementario (LAC). El resto de la superficie de los dientes fue cubierta con un barniz de uñas resistente a la corrosión. Los dientes preparados se sumergieron en una solución desmineralizante de ácido acético (CH3COOH 50mM, KH2PO4 2,2 mM, CaC ^FhO 2,2mM; pH 4,4 ajustado con KOH) en agitación y temperatura ambiente por 5 días. La solución se renovó cada 24 horas. A collection of maxillary molars extracted for different therapeutic reasons was performed at the Dental Clinic of the University of Chile, with the prior authorization of patients informed verbally and in writing. Fifteen healthy teeth were selected: no caries, no seals, and no other structural alterations of the enamel (cracks, spots, hypoplasias, etc.). On the free faces of the selected teeth, 4 dental enamel surfaces of 2 mm 2 were delimited, all at a distance of 2 mm from the cementoenamel limit (LAC). The rest of the surface of the teeth was covered with a nail varnish resistant to corrosion. The prepared teeth were immersed in a demineralising solution of acetic acid (50 mM CH3COOH, 2.2 mM KH 2 PO 4, 2.2 mM CaC ^ FhO, pH 4.4 adjusted with KOH) under stirring at room temperature for 5 days. The solution was renewed every 24 hours.
Ejemplo 3. Aplicación de tratamientos sobre LMB Las muestras de LMB se repartieron en los siguientes grupos experimentales: Control (LMB sin tratamiento), BF (LMB con aplicación de barniz flúor, Duraphat®), Gel VB (LMB con aplicación de gel de VB sin nano-partículas) y Gel nVBF (LMB con aplicación de composición de gel + 1 % nVBF). Example 3. Application of treatments on LMB The samples of LMB were divided into the following experimental groups: Control (LMB without treatment), BF (LMB with application of fluoride varnish, Duraphat ® ), VB Gel (LMB with VB gel application) without nano-particles) and nVBF Gel (LMB with application of gel composition + 1% nVBF).
Sobre la superficie limpia y seca de cada LMB se aplicó con microbrush una capa delgada de gel según los grupos experimentales descritos previamente. Luego de la primera aplicación, se secó suavemente con aire comprimido por 10 segundos y se aplicó una segunda capa, repitiendo el proceso de secado por otros 10 segundos. El barniz de flúor se aplicó con pincel en una capa delgada sobre la superficie limpia y seca de cada LMB, según indicaciones del fabricante. En la FIG. 1 , se muestra el estado microscópico de las LMB de los distintos grupos experimentales, en vista frontal y transversal, antes de ser sometidos al ensayo de bioactividad. Las imágenes se obtuvieron con microscopía electrónica de barrido (SEM) de: LMB sin tratamiento (Control, FIG. 1A); Barniz de flúor sobre LMB (BF, FIG. 1 B); LMB tratado con Gel VB sin nano-partículas (Gel VB, FIG. 1 C) y LMB con aplicación de composición de gel + 1 % nVBF (Gel nVBF, FIG. 1 D). Se observa que el grupo Control muestra una superficie mineral irregular, con exposición de prismas del esmalte desmineralizado heterogéneamente en distinto nivel de profundidad (7, 2+1 , 9 pm). Las LMB con aplicación de BF cubre completamente la muestra con una combinación de cristales fluoruro de sodio embebidos en una matriz de resinas orgánicas y de grosor variable (10,8+2,9 pm). El grupo Gel VB presentó una superficie lisa y uniforme, formando una capa delgada (6,7±1 ,2 pm) y con poca presencia de restos minerales atrapados en su espesor. El grupo Gel nVBF presentó una superficie nano-porosa de capa delgada (7, 0+0, 7 pm) con ocurrencia de cracks, y que cubre la totalidad del esmalte dental desmineralizado. On the clean and dry surface of each LMB, a thin layer of gel was applied with microbrush according to the experimental groups previously described. After the first application, it was dried gently with compressed air for 10 seconds and a second layer was applied, repeating the drying process for another 10 seconds. The fluoride varnish was applied with a brush in a thin layer on the clean and dry surface of each LMB, according to the manufacturer's instructions. In FIG. 1, the microscopic state of the LMBs of the different experimental groups is shown, in frontal and transversal view, before being subjected to the bioactivity test. The images were obtained with scanning electron microscopy (SEM) of: LMB without treatment (Control, FIG.1A); Fluorine varnish on LMB (BF, FIG 1B); LMB treated with VB Gel without nano-particles (Gel VB, FIG.1C) and LMB with application of gel composition + 1% nVBF (Gel nVBF, FIG.1D). It is observed that the Control group shows an irregular mineral surface, with exposure of demineralized enamel prisms heterogeneously at different level of depth (7, 2 + 1, 9 pm). The LMB with BF application completely covers the sample with a combination of sodium fluoride crystals embedded in a matrix of organic resins and variable thickness (10.8 + 2.9 p.m.). The Gel VB group presented a smooth and uniform surface, forming a thin layer (6.7 ± 1, 2 pm) and with little presence of mineral remains trapped in its thickness. The Gel nVBF group presented a thin-film nano-porous surface (7.0 +/- 0.7 p.m.) with the occurrence of cracks, covering the entire demineralized tooth enamel.
Ejemplo 4. Ensayos de bioactividad Example 4. Bioactivity tests
Los grupos experimentales mencionados previamente se sumergieron en saliva artificial (KCI, NaCI, CaCI2:2H20, NaH2P04:H20, NaS:9H20, Úrea, pH 6,5) con agitación por 12 horas a temperatura ambiente. Luego, se sometieron a un ciclo de remineralización/desmineralización en la secuencia que se detalla a continuación, por 7 días: The experimental groups mentioned previously were immersed in artificial saliva (KCI, NaCl, CaCl 2 : 2H 2 0, NaH 2 P0 4 : H 2 0, NaS: 9H 2 0, Urea, pH 6,5) with stirring for 12 hours at room temperature. Then, they underwent a remineralization / demineralization cycle in the sequence that is detailed below, for 7 days:
- Paso 1 : Inmersión por 3 horas en solución desmineralizante (CH3COOH 50mM, KH2P040,9 mM, CaCI2:2H20 1 ,5mM; pH 4,8 ajustado con KOH), con agitación constante y a temperatura ambiente. - Paso 2: Inmersión por 2 horas en saliva artificial, con agitación constante y a temperatura ambiente. - Step 1: Immersion for 3 hours in demineralizing solution (50mM CH3COOH, 0.9mM KH 2 P0 4 , 0.5mM CaCl 2 : 2H 2 0, pH 4.8 adjusted with KOH), with constant agitation and at room temperature. - Step 2: Immersion for 2 hours in artificial saliva, with constant agitation and at room temperature.
- Paso 3: Inmersión por 3 horas en solución desmineralizante (CH3COOH 50mM, KH2P040,9 mM, CaCI2:2H20 1 ,5mM; pH 4,8 ajustado con KOH), con agitación constante y a temperatura ambiente. - Paso 4: Inmersión por 16 horas en saliva artificial, con agitación constante y a temperatura ambiente. - Step 3: Immersion for 3 hours in demineralizing solution (50mM CH3COOH, 0.9mM KH 2 P0 4 , 0.5mM CaCl 2 : 2H 2 0, pH 4.8 adjusted with KOH), with constant agitation and at room temperature. - Step 4: Immersion for 16 hours in artificial saliva, with constant agitation and at room temperature.
Después de que se completó el ensayo de bioactividad, el área de las lesiones tratadas se analizó mediante microscopía electrónica de barrido (SEM), imágenes que se muestran en la FIG. 2. La FIG. 2A se puede observar una LMB tratada con BF, la que presenta una superficie irregular y heterogénea marcada por la presencia de corpúsculos de material orgánico/mineral, sobre esmalte dental parcialmente cubierto. El grosor resulta también heterogéneo (6, 5+2,0 pm). La FIG. 2B muestra una LMB tratada con Gel VB sin nano-partículas, donde se observa una capa mineral uniforme y más gruesa (5,0±1 ,2 pm) que el grupo Gel nVBF. La FIG. 2C muestra una LMB tratada con Gel nVBF, donde la superficie queda cubierta por una capa mineral densa y delgada (3, 2+0, 5 pm) unida íntimamente con el esmalte subyacente. La FIG. 2D, muestra la superficie del esmalte dental sano, correspondiente a una capa mineral amorfa, densa y continua, de pocos nanómetros de espesor (3, 6+0, 3 pm), que cubre la superficie de los prismas del esmalte subyacente. Como se puede observar, la fase mineral que produce el Gel nVBF es similar a la del esmalte dental sano, siendo particularmente más densa y uniforme cuando el gel contiene nanopartículas. After the bioactivity test was completed, the area of the treated lesions was analyzed by scanning electron microscopy (SEM), images shown in FIG. 2. FIG. 2A can be observed an LMB treated with BF, which presents an irregular and heterogeneous surface marked by the presence of corpuscles of organic / mineral material on partially covered dental enamel. The thickness is also heterogeneous (6, 5 + 2.0 pm). FIG. 2B shows a LMB treated with VB Gel without nano-particles, where a uniform and thicker mineral layer (5.0 ± 1, 2 pm) is observed than the Gel nVBF group. FIG. 2C shows an LMB treated with nVBF Gel, where the surface is covered by a dense and thin mineral layer (3, 2 + 0, 5 pm) intimately linked with the underlying enamel. FIG. 2D shows the surface of healthy dental enamel, corresponding to a dense and continuous amorphous mineral layer, a few nanometers thick (3, 6 + 0, 3 pm), which covers the surface of the prisms of the underlying enamel. As can be seen, the mineral phase that produces nVBF Gel is similar to that of healthy tooth enamel, being particularly denser and even when the gel contains nanoparticles.
En la FIG. 3A, se muestra un gráfico de espectro infrarrojo del barniz fluorado (BF) y el Gel nVBF, antes y después del ensayo de bioactividad, realizado mediante un espectrómetro infrarrojo con transformadas de Fourier - Reflectancia total atenuada (FTIR-ATR). En este gráfico se puede identificar los principales enlaces químicos existentes en los compuestos analizados, lo que permitió caracterizar su estructura y composición química. Se incluyó, además el espectro infrarrojo del esmalte dental sano, a modo de comparación. En el espectro FTIR-ATR de la lesión tratada con Gel nVBF y luego de 7 días de ser sometida a los ciclos de remineralización/desmineralización, se puede observar la presencia de bandas alrededor de 580, 600 y 1 100 cnr1 que corresponden a vibraciones específicas del enlace P-0 (·) característico de la estructura de la hidroxiapatita. El espectro de la lesión tratada con Gel nVBF coincide además con la del esmalte dental sano. El símbolo (A) indica señales asociados a enlaces C-O. Los enlaces Si-O-Si (■) y Si-OH (★) corresponden a señales de la estructura del vidrio bioactivo (VB). In FIG. 3A, an infrared spectrum graph of the fluorinated varnish (BF) and the nVBF Gel is shown, before and after the bioactivity test, performed by means of an infrared spectrometer with Fourier transforms - Attenuated total reflectance (FTIR-ATR). In this graphic it is possible to identify the main chemical bonds existing in the analyzed compounds, which allowed to characterize its structure and chemical composition. In addition, the infrared spectrum of healthy tooth enamel was included as a comparison. In the FTIR-ATR spectrum of the lesion treated with Gel nVBF and after 7 days of being subjected to the cycles of remineralization / demineralization, it can be observed the presence of bands around 580, 600 and 1 100 cnr 1 that correspond to vibrations specific to the P-0 bond (·) characteristic of the structure of hydroxyapatite. The spectrum of the lesion treated with nVBF Gel also coincides with that of healthy tooth enamel. The Symbol (A) indicates signals associated with CO links. The Si-O-Si (■) and Si-OH (★) bonds correspond to signals from the structure of bioactive glass (VB).
En la FIG. 3B, se muestra dos gráficos de espectro infrarrojo: el primero del Gel VB y el segundo de Gel nVBF, antes y después del ensayo de bioactividad, realizado mediante un espectrómetro infrarrojo con transformadas de Fourier - Reflectancia total atenuada (FTIR-ATR). Se puede observar que el espectro de la lesión tratada con el Gel VB sin nano-partículas muestra una transformación parcial de la fase de vidrio bioactivo a los 7 días de tratamiento, sin la aparición completa de la banda de hidroxiapatita. Estos resultados indican que el Gel nVBF repara la lesión de caries incipiente con una fase equivalente en su estructura al componente mineral original del esmalte (hidroxiapatita), y que la formación de apatita bien cristalizada ocurre solamente cuando el gel contiene nanopartículas de vidrio bioactivo fluorado. In FIG. 3B, two infrared spectrum graphs are shown: the first of Gel VB and the second of Gel nVBF, before and after the bioactivity test, performed by means of an infrared spectrometer with Fourier transforms - Attenuated total reflectance (FTIR-ATR). It can be observed that the spectrum of the lesion treated with the VB Gel without nano-particles shows a partial transformation of the bioactive glass phase after 7 days of treatment, without the complete appearance of the hydroxyapatite band. These results indicate that the nVBF Gel repairs the incipient caries lesion with a phase equivalent in structure to the original mineral component of the enamel (hydroxyapatite), and that the formation of well-crystallized apatite occurs only when the gel contains fluorinated bioactive glass nanoparticles.
Ejemplo 5. Ensayos de desafío ácido Terminado el ensayo de bioactividad, unas muestras de Gel VB y Gel nVBF se sumergieron en 200 mL de bebida cola por 2 minutos (pH 2,4) y otras en 200 mL de ácido láctico, también por 2 minutos (pH 4,4). Esta prueba permitió medir la estabilidad de la fase mineral formada en condiciones que simulan la acción desmineralizante de bacterias cariogénicas o de erosión dental producida por el consumo de bebidas ácidas. Como se puede observar en la FIG. 4 que muestra imágenes SEM de secciones transversales, la fase/capa mineral reparadora que producen los geles, tanto el Gel VB como el Gel nVBF son capaces de resistir los exigentes tratamientos ácidos. Example 5. Acid Challenge Tests After the bioactivity test, samples of Gel VB and nVBF Gel were immersed in 200 mL of cola drink for 2 minutes (pH 2.4) and others in 200 mL of lactic acid, also for 2 minutes. minutes (pH 4.4). This test allowed to measure the stability of the mineral phase formed in conditions simulating the demineralizing action of cariogenic bacteria or dental erosion produced by the consumption of acidic beverages. As can be seen in FIG. 4 which shows SEM images of cross sections, the repairing phase / mineral layer produced by the gels, both the VB Gel and the nVBF Gel are able to withstand the demanding acid treatments.

Claims

REIVINDICACIONES
1. Una composición para la reparación de caries dental incipiente que comprende una matriz y nano-partículas incluido en dicha matriz, CARACTERIZADA porque dicha matriz y dichas nanopartículas incluyen iones de silicio, calcio y fosfato.A composition for the repair of incipient dental caries comprising a matrix and nano-particles included in said matrix, CHARACTERIZED because said matrix and said nanoparticles include silicon, calcium and phosphate ions.
2. La composición de la reivindicación 1 , CARACTERIZADA porque dicha matriz es un gel. 2. The composition of claim 1, CHARACTERIZED because said matrix is a gel.
3. La composición de la reivindicación 1 , CARACTERIZADA porque dicha matriz y dichas nano-partículas comprenden dióxido de silicio (S1O2), óxido de calcio (CaO) y pentóxido de fósforo (P2O5).  3. The composition of claim 1, CHARACTERIZED in that said matrix and said nano-particles comprise silicon dioxide (S1O2), calcium oxide (CaO) and phosphorus pentoxide (P2O5).
4. La composición de la reivindicación 3, CARACTERIZADA porque las nano- partículas comprenden adicionalmente flúor (F).  4. The composition of claim 3, CHARACTERIZED in that the nanoparticles additionally comprise fluorine (F).
5. La composición de la reivindicación 3, CARACTERIZADA porque la matriz tiene una composición molar correspondiente a 58Ca0:36Si02:6P20s.  5. The composition of claim 3, CHARACTERIZED because the matrix has a molar composition corresponding to 58Ca0: 36Si02: 6P20s.
6. La composición de la reivindicación 4, CARACTERIZADA porque las nano- partículas tienen una composición molar correspondiente a 58SiO2:40CaO:5P2O5:F. 6. The composition of claim 4, CHARACTERIZED in that the nanoparticles have a molar composition corresponding to 58SiO 2 : 40CaO: 5P 2 O 5 : F.
7. La composición de la reivindicación 1 , CARACTERIZADA porque comprende entre 97,5-99,5% de matriz y 0,5-2, 5% de nano-partículas.  7. The composition of claim 1, CHARACTERIZED because it comprises between 97.5-99.5% matrix and 0.5-2.5% nanoparticles.
8. La composición de la reivindicación 7, CARACTERIZADA porque comprende entre 97,5-99,5% de matriz con composición molar correspondiente a 58Ca0:36Si02:6P205 y 0,5-2, 5% de nano-partículas de composición molar correspondiente a 58SiO2:40CaO:5P2Os:F. 8. The composition of claim 7, CHARACTERIZED because it comprises between 97.5-99.5% of matrix with molar composition corresponding to 58Ca0: 36Si02: 6P205 and 0.5-2.5% of nano-particles of corresponding molar composition a 58SiO 2 : 40CaO: 5P 2 Os: F.
9. Un método para la preparación de una composición para la reparación de caries dental incipiente, CARACTERIZADO porque comprende los pasos de:  9. A method for the preparation of a composition for the repair of incipient dental caries, CHARACTERIZED because it comprises the steps of:
- preparar nano-partículas que incluyen iones de silicio, calcio y fosfato mediante el método sol-gel;  - prepare nano-particles that include silicon, calcium and phosphate ions by the sol-gel method;
- añadir dichas nano-partículas a una solución precursora de una matriz que incluye iones de silicio, calcio y fosfato; y - permitir gelificar la mezcla anterior, hasta obtener la composición. - adding said nano-particles to a precursor solution of a matrix that includes silicon, calcium and phosphate ions; Y - allowing the above mixture to gel, until the composition is obtained.
10. El método de la reivindicación 9, CARACTERIZADO porque las nano-partículas se preparan mediante los pasos de: 10. The method of claim 9, CHARACTERIZED because the nano-particles are prepared by the steps of:
- agregar nitrato de calcio (Ca(N03)2‘3H20) disuelto en agua a una solución con tetraortosilicato en etanol 95% para formar una primera mezcla; - add calcium nitrate (Ca (N03) 2 '3H 2 0) dissolved in water to a solution with tetraorthosilicate in 95% ethanol to form a first mixture;
- ajustar el pH de la primera mezcla entre 1 y 2;  - adjust the pH of the first mixture between 1 and 2;
- agregar a la primera mezcla una solución de dihidrógeno de fosfato de amonio (NH4H2P04) y fluoruro de amonio (NH4F) en agua para formar una segunda mezcla; - adding to the first mixture a solution of ammonium phosphate dihydrogen (NH 4 H 2 P0 4 ) and ammonium fluoride (NH 4 F) in water to form a second mixture;
- ajustar el pH de la segunda mezcla entre 10 y 11 ;  - adjust the pH of the second mixture between 10 and 11;
- agitar la mezcla obtenida del paso anterior; y  - stirring the mixture obtained from the previous step; Y
- mantener en reposo la segunda mezcla para obtener un precipitado que contiene las nano-partículas.  - keeping the second mixture at rest to obtain a precipitate containing the nanoparticles.
11. El método de la reivindicación 10, CARACTERIZADO porque la solución de nitrato de calcio (Ca(N03)2‘3H20) en agua posee una concentración de entre 6,0-11. The method of claim 10, characterized in that the solution of calcium nitrate (Ca (N03) 2 '3H 2 0) in water has a concentration of between 6.0-
7,0% p/v. 7.0% p / v.
12. El método de la reivindicación 10, CARACTERIZADO porque la solución de dihidrógeno de fosfato de amonio (NH4H2P04) en agua posee una concentración de entre 0,10-0,20% p/v. 12. The method of claim 10, CHARACTERIZED in that the ammonium phosphate dihydrogen solution (NH 4 H 2 PO 4 ) in water has a concentration of between 0.10-0.20% w / v.
13. El método de la reivindicación 10, CARACTERIZADO porque la solución de fluoruro de amonio (NH4F) en agua posee una concentración de entre 0,01-0,05% p/v. 13. The method of claim 10, CHARACTERIZED in that the solution of ammonium fluoride (NH 4 F) in water has a concentration of between 0.01-0.05% w / v.
14. El método de la reivindicación 10, CARACTERIZADO porque luego de ajustar el pH de la segunda mezcla, ésta se agita por 48 horas a 30°C. 14. The method of claim 10, CHARACTERIZED because after adjusting the pH of the second mixture, it is stirred for 48 hours at 30 ° C.
15. El método de la reivindicación 10, CARACTERIZADO porque el precipitado con las nano-partículas adicionalmente se purifica mediante centrifugación/re- dispersión en agua a 12.000 rpm. 15. The method of claim 10, CHARACTERIZED in that the precipitate with the nano-particles is further purified by centrifugation / re-dispersion in water at 12,000 rpm.
16. El método de la reivindicación 15, CARACTERIZADO porque las nano- partículas purificadas se liofilizan y posteriormente se calcinan a 700°C por 3 horas. 16. The method of claim 15, CHARACTERIZED in that the purified nanoparticles are lyophilized and subsequently calcined at 700 ° C for 3 hours.
17. El método de la reivindicación 9, CARACTERIZADO porque la solución precursora de la matriz se prepara mediante los pasos de: 17. The method of claim 9, CHARACTERIZED in that the precursor solution of the matrix is prepared by the steps of:
- hidrolizar tetraetilortisolicato Si(OC2Hs)4 en etanol 95% acidificado; y - hydrolyze tetraethylortisolicate Si (OC2Hs) 4 in 95% acidified ethanol; Y
- agregar trietilfosfato (C2Hs)3P04 (>99%) y de Ca(N03)2‘3H20 para formar la solución precursora de la matriz. - add triethylphosphate (C 2 Hs) 3P0 4 (> 99%) and Ca (N03) 2 '3H 2 0 to form the parent precursor solution.
18. El método de la reivindicación 17, CARACTERIZADO porque el tetraetilortisolicato Si(OC2Hs)4en etanol posee una concentración entre 27-29% v/v. 18. The method of claim 17, CHARACTERIZED in that the tetraethylortisolicate Si (OC2Hs) 4 in ethanol has a concentration between 27-29% v / v.
19. El método de la reivindicación 17, CARACTERIZADO porque la concentración de trietilfosfato (C2Hs)3P04 (>99%) en la solución precursora es entre 2, 0-2, 3% v/v. 19. The method of claim 17, CHARACTERIZED in that the concentration of triethylphosphate (C 2 Hs) 3P0 4 (> 99%) in the precursor solution is between 2.0-2.3% v / v.
20. El método de la reivindicación 17, CARACTERIZADO porque la concentración de Ca(N03)2‘3H20 en la solución precursora es entre 3, 0-3, 5% p/v. 20. The method of claim 17, CHARACTERIZED in that the concentration of Ca (N03) 2 '3H 2 0 in the precursor solution is between 3.0-3.5% w / v.
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Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
CADIZ, M. ET AL.: "Optimization de la preparation de andamios bionanocompósitos para regeneration ósea basados en biopolíméros y nanopartículas bioceramicas.", FACULTAD ODONTOLOGIA - UNIVERDAD DE CHILE, 12 December 2016 (2016-12-12), XP055622843, Retrieved from the Internet <URL:http://repositorio.uchile.cl/handle/2250/141797> [retrieved on 20190326] *
TAPIA, V. ET AL.: "Síntesis de resinas compuestas a base de hanoparticulas ceramicas con propiedades remineralizante y de liberation de fluoruro. Trabajo de Investigation", REQUISITE PARA OPTAR AL GRADO DE MAGISTER EN CIENCIAS ODONTOLOGICAS, ;ON MENTION EN CARIOLOGIA, 4 September 2017 (2017-09-04), pages 1 - 63, XP055622838, Retrieved from the Internet <URL:http://repositorio.uchile.cl/handle/2250/144979> [retrieved on 20190326] *
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