Powder for slow release of active component on teeth

Abstract

The invention relates to a powder for use in treating tooth surfaces with a powder jet device, wherein the powder comprises (a) an organic compound in powder form, wherein the organic compound has a melting point of 35 – 170 °C and a solubility in water at 25 °C of < 10 g / l, (b) a material in powder form having pores, comprising pores with a pore diameter < 50 nm, wherein the material has an average particle size d50 < 50 µm, and (c) an active ingredient absorbed in the pores of the material.

Description

[0001] Powder for slow release of active component on teeth

[0002] The invention relates to a powder for use in treating tooth surfaces with a powder jet device that enables a slow release of an active component on teeth. The invention further relates to a coating on tooth surfaces obtainable by applying the powder.

[0003] Professional dental prophylaxis is an important periodic treatment that helps to maintain oral health as it removes the biofilm and calculus that patients cannot remove in their daily home dental care. Professional dental prophylaxis comprises powder jet cleaning or air polishing, which is particularly effective as it allows to reach and clean all tooth surfaces and the interspaces between them as well as implants, brackets and appliances. The professional dental prophylaxis is an important treatment that helps to maintain oral health since it removes the biofilm and calculus that a patient cannot remove during his daily home dental care.

[0004] In the powder jet cleaning process, a powder jet device is used, wherein a powder is sprayed with a gaseous carrier medium, usually air, onto tooth surfaces, which allows an efficient cleaning of the teeth. Additionally, or as an alternative to a gaseous carrier medium, a liquid carrier medium, for example water may be used. Powder jet cleaning is performed with a powder jet device and it is particularly effective because it does not require repetitive movements. Further, it is faster than other cleaning methods and it needs relatively low training to be learned correctly.

[0005] The clean teeth obtained after powder jet cleaning represent an opportunity for enhancing effects of for example tooth fluoridization or remineralization due to the facilitated and direct contact of the product to the tooth surface. However, additional chemical treatments require generally longer contact time to allow the chemical reactions to take place. Among these additional chemical treatments, examples are tooth fluoridization to improve the enamel acid resistance, tooth remineralization to i repair the external part of the tooth, anti-bacterial treatment to slow down the biofilm recolonization or healing helping means with anti-inflammatory ingredients or bone growth factors.

[0006] For supragingival treatments such as fluoridization, creams or varnishes are available that can be deposited onto the teeth. EP 2 455 064 A1 discloses polymer filled sheets like Periochip for subgingival treatments. In DE 10 114244 A1 , thick gels as for example Ligosan for subgingival anti-bacterial maintaining are described.

[0007] However, all these methods have their limitations. For the supragingival deposition the contact time is often too short to get a real chemical effect. In general, contact time for at least a few hours would be required. However, the patient is usually not willing to remain for 20 minutes or longer on the dental chair to allow the chemical reaction to start. Further, the aqueous environment of the mouth quickly solves and removes all water-soluble compounds. For the subgingival additives, there is a flux of body fluid which expels all chemicals which are not fixed inside the pockets. But fixing the active ingredient with the presence of a support material which is quite thick is also a barrier against the soft tissue re-attachment. Furthermore, higher product concentrations are needed.

[0008] When developing the present invention, it has been found that a powder comprising an organic compound with a melting point preferably < 165 °C can form a coating on the tooth surface when applied by a powder jet device. This coating may contain an active ingredient or active component. However, further investigations have shown that most of the active ingredient is released too fast.

[0009] Therefore, it is an object of the present invention to provide a protection system for tooth surfaces that overcomes the above problems, which is easily applicable and allows a slow delivery of active ingredients to the tooth surface.

[0010] This object is achieved according to the invention by a powder for use in treating tooth surfaces with a powder jet device according to claim 1 . The object is also achieved by the coating according to claim 13. Preferred embodiments of the invention are subject to the dependent claims as well as the following description.

[0011] One embodiment of the invention relates to a powder for use in treating tooth surfaces with a powder jet device, wherein the powder comprises

[0012] (a) an organic compound in powder form, wherein the organic compound has a melting point of 35 - 170 °C and a solubility in water at 25 °C of < 10 g / l ,

[0013] (b) a material in powder form having pores, comprising pores with a pore diameter < 50 nm, wherein the material has an average particle size d50< 50 pm, and

[0014] (c) an active ingredient absorbed in the pores of the material.

[0015] It has surprisingly been found that the powder according to the invention, when applied to tooth surfaces with a powder jet device, gives a coating on the tooth surfaces which protects the tooth and provides a slow release of the active ingredient to the tooth surface. When the powder according to the invention is projected onto a surface with a stream of air, i.e. when using the powder in a powder jet device that is usually used to clean tooth surfaces, the powder adheres to the tooth surface forming a coating. Without being bound to this explanation, it is believed that due to the kinetic energy delivered to the powder, the powder undergoes a melting process at the point of collision with the tooth surface and forms a coating on the tooth surface (kinetic melting). The small average particle size of the material d50< 50 pm ensures that the material is not abrasive so that the coating is not removed. The active ingredient is not in the structure of the organic compound forming the coating, which has been found to result in a too fast release, but the active ingredient is absorbed in the pores of the material which ensures a slow release.

[0016] One advantage of the powder according to the invention is that the use in a conventional powder jet device results in coating in the right position at the tooth surface location. The powder comprises an organic compound, a material having pores and an active ingredient that is absorbed in the pores of the material. The active ingredient or active component is for example a pharmaceutically active compound or ingredient, which means a therapeutically efficient amount of a pharmaceutically active compound or ingredient. The term “treating tooth surface(s)” means in the sense of the present invention “applying to tooth surface(s)”. Treating or applying to tooth surface(s) is a typical use of a powder jet device, wherein a powder is sprayed with a carrier medium, for example air, onto tooth surfaces. In a preferred embodiment of the invention, the powder for use in treating tooth surfaces with a powder jet device is a powder for use in coating tooth surfaces with a powder jet device. The treating is preferably a therapeutic treating and the use of the powder in treating is preferably a therapeutic use in treating.

[0017] The slow release allows the active ingredient, preferably a pharmaceutically active compound, a tooth fluoridization agent or tooth remineralization agent, to stay long enough on the tooth surface to act on the tooth surface or to deliver the active ingredient from this coating directly to the tooth surface, i.e. in the correct position. The absorption in the pores of the material comprising pores and the incorporation into the coating ensures a slow release of the active ingredient. The absorption in the pores of the material can be achieved, for example, by adding a solution of the active ingredient in a solvent to the material having pores and evaporating the solvent.

[0018] The powder according to the present invention is easily applicable with conventional powder jet devices, in particular after tooth cleaning and the same powder jet device can be used for the cleaning and, subsequently, for applying the powder according to the invention to the cleaned tooth surfaces. Only the powder has to be changed.

[0019] In a preferred embodiment of the invention, the powder for use in treating tooth surfaces with a powder jet device comprises > 30 wt.-%, based on the total weight of the powder, more preferably > 50 wt.-%, even more preferably > 60 wt.-%, most preferably > 70 wt.-%, of the organic compound having a melting point of 35 - 170 °C and a solubility in water at 25 °C of < 10 g / l.

[0020] In a preferred embodiment of the invention, the powder for use in treating tooth surfaces with a powder jet device comprises < 40 wt.-%, based on the total weight of the powder, of the material in powder form having pores, more preferably < 30 wt.-%, even more preferably < 20 wt.-%, most preferably < 15 wt.-%.

[0021] According to a preferred embodiment of the invention, the powder comprises 0.01 to 20 wt.-%, based on the total weight of the powder, of an active compound or ingredient. More preferably, the powder comprises 0.05 wt.-% to 15 wt.-%, based on the total weight of the powder, of an active ingredient, even more preferably 0.1 wt.-% to 10 wt.-%, most preferably 0.1 wt.-% to 5 wt.-%.

[0022] Within the meaning of the present invention, it should be understood that the amounts of the components of the powder, given in wt.-% (weight-%), sum up to 100 %. An example is a powder comprising 50 wt.-% of the organic compound, 40 wt.-% of the material having pores, 7 wt.-% active ingredient and 3 wt.-% additional components such as flow aids, flavourings etc.

[0023] An organic compound according to the invention is understood to be a chemical compound containing one or more carbon atom(s), in particular a carbon skeleton.

[0024] In a preferred embodiment of the invention, the melting point of the organic compound in the powder for use in treating tooth surfaces with a powder jet device is 35 - 165 °C, more preferred 37 - 162 °C, even more preferred 40 - 158 °C and most preferred 42 - 156 °C. The low melting points give an advantageous coating as the kinetic melting is promoted. The solubility of the organic compound in water at 25 °C is preferably < 5 g / l (gram per liter), more preferably < 2 g / l and most preferably < 1 g / l in water at 25 °C. The solubility in water is related to distilled water (pH about 7.0). The limited solubility in water enhances the stability of the coating in the aqueous environment of the mouth.

[0025] In the course of the invention, it has been found that the organic compound of the powder according to the invention is preferably selected from the group consisting of fatty acids, fatty alcohols, sterols, hydroxy-substituted aromatic compounds and mixtures thereof. The fatty acids, fatty alcohols, sterols and hydroxy-substituted aro- matic compounds can be optionally substituted and / or (partially) saturated when possible.

[0026] The fatty acids are preferably carboxylic acids with 10 to 24 carbon atoms, more preferably 12 to 22 carbon atoms, even more preferred are tridecanoic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid, arachidic acid and mixtures thereof. The most preferred fatty acids are palmitic acid, stearic acid, arachidic acid and mixtures thereof.

[0027] The fatty alcohols are preferably alcohols with 10 to 24 carbon atoms, more preferably 12 to 22 carbon atoms, even more preferably stearyl alcohol or lauryl alcohol.

[0028] The sterol is preferably selected from the group consisting of cholesterol, beta-sist- osterol, campesterol, stigmasterol, ergosterol, brassicasterol and mixtures thereof. The sterol is more preferably cholesterol and / or beta-sistosterol.

[0029] The hydroxy-substituted aromatic compounds are preferably hydroxy benzenes or a hydroxy toluenes, preferably butylated hydroxytoluene (BHT) or butylated hydroxy anisole (BHA). Most preferred as hydroxy-substituted aromatic compound is butylated hydroxytoluene (BHT).

[0030] The advantage of using the above organic compounds as powder for forming the coating or deposition is that the organic compound forms a layer on the surface. The porosity of the substrate (tooth) is not blocked so that the exchange of the tooth surface with the environment is not significantly modified. Further, the body functions such as tissue attachment is also not blocked. Additionally, the diffusion of the fluid within the medium can also be used to fine tune the delivery of the active ingredients).

[0031] The powder according to the invention is deposited on the tooth surface due to the kinetic energy delivered to the powder with the air. The deposition can be made supragingivally on enamel or exposed dentine, for example with the standard AIRFLOW handpiece of EMS or it can be made subgingivally, for example with the EMS PERIOFLOW subgingival nozzle. In a preferred embodiment of the invention, the powder should be projected towards the tooth surface with a powder jet device together with a gaseous carrier medium, in particular air. The powder is projected towards the tooth surface with the air. The air may contain water, preferably wherein water represents less than 10 mL / min, in particular, less than 5 mL / min. In a preferred embodiment, the powder jet device is used in the absence of water.

[0032] The use in treating tooth surfaces with a powder jet device according to the invention means spraying the powder onto a tooth surface with a conventional powder jet device. The powder then forms a coating on the tooth surface.

[0033] In the context of this invention, the d50value (average particle size) is the particle size at which 50 % of the particles are smaller than the d50value in terms of volume and 50 % of the particles are larger than the d50value in terms of volume. This applies also to the d90values, where 90 % are smaller than the d90value regarding volume. The d-values according to the invention are determined by a laser diffraction method using a dry dispersion (Malvern Mastersizer 2000, equipped with a Sci- rocco dry dispersion unit, operated at 1 .5 bar).

[0034] The average particle size of the material d50is < 50 pm, preferably < 20 pm, more preferably < 10 pm. The d90is preferably < 120 pm, more preferably < 100 pm, even more preferably < 80 pm.

[0035] The material in powder form having pores according to the invention is preferably a porous material. A porous material according to the invention is understood to be a material having pores. That means, the material in powder form having pores can also be named a porous material in powder form. This material in powder form having pores comprises pores with a pore diameter < 50 nm, preferably <50 nm and > 2 nm. Such material can also be named mesoporous material. According to the invention, the material in powder form having pores preferably comprises pores with a pore diameter < 20 nm, more preferably < 10 nm. In both cases, the pores are more preferably > 2nm. In a preferred embodiment of the invention, the material in powder form having pores is silica and / or zeolite. The pore sizes or pore diameters and the cumulative pore volume of the material are measured by nitrogen absorption according to the Barrett-Joyner-Halenda method (BJH method), which is a BET method (ISO 9277:2010). The result of this BJH method is a pore volume and a cumulative pore volume in dependence of the pore diameter, i.e. a pore size distribution. See also E.P. Barret, L.G. Joyner, P.H. Halenda, J. Am. Chem. Soc. 73 (1951 ) 373 ; J.C. Groen, L.A.A. Peffer, J. Perez- Ramirez, Microporous Mesoporous Mater. 60 (2003) 1 ; S.J. Gregg, K.S.W. Sing, “Adsorption, Surface Area and Porosity" , 2nd ed., Academic Press, London, 1982.

[0036] In a preferred embodiment of the invention, 90 % of the cumulative pore volume of the material in powder form having pores are from pores with pore diameters < 20 nm, more preferably < 15 nm, most preferably < 8 nm.

[0037] The active ingredient (active compound), which is understood according to the invention as having an effect on the teeth or the human or animal body, can preferably be a pharmaceutically active compound, tooth fluoridization agent or tooth remineralization agent. Thereby, the invention allows to create an intelligent delivery system for an active ingredient, for example a pharmaceutically active compound, which is placed on the tooth surface and with a release of the active ingredient.

[0038] The active ingredient according to the invention is preferably selected from the group consisting of anti-inflammatory agents, anti-microbial agents, anti-bacterial agents, anti-viral agents, bones growth factors, tooth fluoridization agents and tooth remineralization agents. Anti-inflammatory agents, anti-microbial agents, anti-bacterial agents, anti-viral agents, bones growth factors are understood to be pharmaceutically active compounds or pharmaceutically active ingredients. The powder can comprise one or more active ingredients, for example one, two, three, four or five. The powder can also comprise one or more organic compound and / or one or more materials having pores, for example one, two, three, four or five.

[0039] A powder according to the invention means a substance in the form of small particles. The average particle size (d50) of the powder according to the invention, i.e. the powder in total comprising particles of the organic compound and particles of the material, is preferably 0,5 to 500 pm, more preferably 1 - 300 pm, even more preferably 2 to 200 pm, most preferably 5 to 100 pm. The particle sizes may be adapted to the field of application. For example, a smaller average particle size of the particles is preferred for treating subgingival tooth surfaces, in particular about 0,5 to 50 pm, more preferably 1 to 30 pm. For treating supragingival tooth surfaces, a larger average particle size can be used, preferably 0,5 to 200 pm, more preferably 2 to 100 pm.

[0040] In a further preferred embodiment of the invention, the powder additionally comprises a flow aid, a bleaching agent and / or a flavouring agent. The total amount of these additional substances is preferably 0.2 to 5 wt.-%, based on the total weight of the powder, more preferably 0.5 to 2 wt.-%.

[0041] The flow aid is preferably selected from the group consisting of silicon dioxide (silica, in particular amorphous silica), aluminium silicate and / or aluminium hydroxide. Silicon dioxide is more preferred, in particular in an amount of 0.2 to 3 wt.-%, most preferably 0.5 to 2 wt.-%, based on the total weight of the powder.

[0042] Preferred bleaching agents are peroxides such as magnesium, calcium or zinc peroxides, persulfates such as sodium, potassium or ammonium persulfates or perborates.

[0043] In a preferred embodiment of the invention, the powder comprises less than 10 wt.- % of an abrasive powder (abrasive powder jet cleaning powder), more preferably less than 5 wt.-%, even more preferably less than 2 wt.-%, in particular less than 1 wt.-% of an abrasive powder, each based on the total weight of the powder.

[0044] According to the invention, an abrasive powder or abrasive jet cleaning powder is meant to be a powder that is used in a powder jet device for cleaning tooth surfaces. The abrasive powders or abrasive jet cleaning powders are preferably sodium hydrogen carbonate, calcium carbonate, aluminium hydroxide, alditols, amino acids, sugars, cyclodextrins or mixtures thereof. Therefore, the powder according to the invention contains preferably less than 10 wt.-%, more preferably less than 5 wt.-%, even more preferably less than 2 wt.-%, most preferably less than 1 wt.-%, based on the total weight of the powder, of sodium hydrogen carbonate, calcium carbonate, aluminium hydroxide, alditols, amino acids, sugars, cyclodextrins or mixtures thereof. The alditol is preferably erythritol and the amino acid preferably glycine. The sugar is preferably trehalose or tagatose. Therefore, it is preferred that the powder according to the invention comprises less than 10 wt.-%, more preferably less than 5 wt.-%, even more preferably less than 2 wt.-%, most preferably less than 1 wt.-%, based on the total weight of the powder, of sodium hydrogen carbonate, calcium carbonate, aluminium hydroxide, erythritol, glycine, trehalose, tagatose, cyclodextrins or mixtures thereof.

[0045] In a further preferred embodiment of the invention, the powder comprises less than 10 wt.-%, preferably less than 5 wt.-%, more preferably less than 2 wt.-%, most preferred less than 1 wt.-% , based on the total weight of the powder, of one or more chemical compound(s) having a melting point > 170 °C, more preferably having a melting point > 165 °C, most preferably > 160 °C, and / or having a solubility in water at 25 °C of > 10 g / l, preferably > 5 g / l, more preferably > 2 g / l, most preferably >1 g / l.

[0046] The powder according to the invention comprises an active ingredient (active component). An active ingredient is understood according to the invention as an active ingredient which may have an effect on the teeth or the human or animal body in general. Preferred active ingredients according to the invention are pharmaceutically active compounds, tooth fluoridization agents or tooth remineralization agents, more preferably anti-inflammatory agents, anti-microbials, anti-bacterial agents, anti-viral agents, bone growth factors, tooth fluoridization agents and tooth remineralization agents (tooth repair agents).

[0047] The anti-inflammatory agent according to the invention is preferably selected from the group consisting of Aceclofenac, Acemetacin, Acetaminosalol, Acetylsalicylic Acid, Alclofenac, Alminoprofen, a-Bisabolol, Amfenac, Bromfenac, Benoxaprofen, Benzpiperylon, Bermoprofen, Bromosaligenin, Bucloxic Acid, Bufexamac, Bu- madizon, Butibufen, Carprofen, Cinmetacin, Clidanac, Clopirac, Diclofenac, Diclofenac Sodium, Diflunisal, Ditazol, Enfenamic Acid, s-Acetamidocaproic Acid Bendazac, Etodolac, Etofenamate, Felbinac, Fenbufen, Fenclozic Acid, Fendosal, Fenoprofen, Fentiazac, Fepradinol, Flufenamic Acid, Flunoxaprofen, Flurbiprofen, Gentisic Acid, Glucametacin, Glycol Salicylate, Ibufenac, Ibuprofen, Ibuproxam, Indomethacin, Indoprofen, Isofezolac, Isoxepac, Isoxicam, Ketoprofen, Ketorolac, Lo- moxicam, Lonazola, Lonazolac, Loxoprofen, Meclofenamic Acid, Meloxicam, Mesalamine, Metiazinic Acid, Mofebutazone, Mofezolac, Naproxen, Niflumic Acid, Olsalazine, Oxaceprol, Oxametacine, Oxaprozin, Oxicams, Oxyphenbutazone, Paranyline, Parsalmide, Perisoxal, Phenyl Salicylate, Pirazolac, Piroxicam, Pirpro- fen, Pranoprofen, Proprionic Acids, Protizinic Acid, Salacetamide, Salicilic Acid, Salicylamide O-Acetic Acid, Salicylsulfuric Acid, Sulfasalazine, Sulindac, Suprofen, Suxibuzone, Talniflumate, Tenoxicam, Terofenamate, Tiaprofenic Acid, Tiaramide, Tinoridine, Tolfenamic Acid, Tolmetin, Tropesin, Ximoprofen, Zaltoprofen, Zileuton and Zomepirac.

[0048] The antimicrobial agent is preferably selected from the group consisting of sulfonamides, phenolics, quaternary ammonium salts, cetylpyridinium chloride (CPC), chlorhexidine and salts thereof. Anti-bacterial agents are preferably penicillins, cephalosporins, tetracycline, doxycycline, chloramphenicol, and erythromycin.

[0049] The bone growth factor is preferably Emdogain® (enamel matrix derivative), BMP (bone morphogenetic protein) or calcium phosphate. The tooth fluoridization agent can be any fluoride containing or delivering compound such as fluoride salts, for example sodium fluoride or amino fluorides etc. The remineralization agent is preferably selected from the group consisting of bioglass, nano-hydroxyapatite, amorphous hydroxy apatite and calcium phosphate.

[0050] It is also preferred that the powder for use in treating tooth surfaces with a powder jet device according to the invention consists of the described components.

[0051] Preferably, a coating of tooth surface(s) is obtained when the deposition efficiency of the powder according to the invention, measured in % (defined as the powder mass sticking on the surface divided by powder mass projected towards the surface) is > 1 %, more preferably > 3%, even more preferably > 5 % by using a powder jet device in the typical process that is also used for cleaning the teeth with a powder jet device.

[0052] It has surprisingly been found that fatty acids, hydroxy-substituted aromatic compounds and sterols are particularly efficient regarding deposition efficiency, which is defined to be the quantity of a powder which sticks to the surface versus quantity of powder delivered from the device. Fatty acids, sterols and hydroxy-substituted aromatic compounds have a deposition efficiency which is ten times higher than the deposition efficiency of PLGA that is used in the prior art (poly(lactic-co-glycolic acid)).

[0053] One of the reasons for this enhanced efficiency is considered to be the melting point of the fatty acids, sterols and hydroxy-substituted aromatic compounds according to the examples, because PLGA usually has a melting point of around 170 - 200 °C, depending on the ratio of lactic and glycolic acid in the PLGA (95:5 has a melting point of about 173 °C and 10:90 of about 200 °C). A melting point of less than 165 °C of the powder according to the invention, however, gives a much more efficient coating and therefore a much more efficient deposition efficiency of the powder when using it in a powder jet device for treating tooth surfaces.

[0054] For drug release, the powder may contain active components, like anti-inflammatory (e.g. aspirine), bone growth factor (e.g. BMP, Emdogain®, Calcium phosphate), antimicrobials (e.g. CPC, Chlorhexidine, antibiotics), fluoridization agents (sodium fluoride, amino-fluoride etc.), tooth repair agents (nano-hap, amorphous hap, calcium phosphate) or desensitizing agent (arginine, potassium chloride). The concentration of the additive is usually between 0.1 to 30 wt.-%., based on the total weight of the powder.

[0055] The powder for use in treating tooth surfaces with a powder jet device is preferably a powder for therapeutic use in treating tooth surfaces with a powder jet device. The invention also relates to a coating obtainable by applying the powder according to the invention to a surface, preferably to a tooth surface with a powder jet device. The coating preferably has aa average thickness of < 100 pm, more preferably < 50 pm, most preferably < 20 pm.

[0056] The above thickness of the coating is the average thickness, determined by calculating the arithmetic average of 3 to 5 measurements of the thickness. The thickness is determined by optical measurement, for example 3D Microscope, step height measurement between a non-coated surface and coated surface (Keyence, VH- 6000).

[0057] The invention also relates to the use of the powder according to the invention in treating tooth surfaces or applying the powder to tooth surfaces. The invention further relates to the use of the powder according to the invention in a powder jet device. This use comprises powder spraying, wherein the powder according to the invention is sprayed with a powder jet device onto the tooth surfaces together with a gaseous carrier medium, in particular air.

[0058] The invention further relates to a process of forming a coating on a tooth surface by applying the powder according to the invention to a tooth surface with a powder jet device. The invention also relates to coating on a tooth surface obtainable by applying the powder according to the invention to a tooth surface with a powder jet device.

[0059] The following examples provide preferred embodiments according to the invention and further exemplify the invention.

[0060] Examples

[0061] The carrier used is mesoporous silica named MESOPOROSIL®. This powder has a mean pore size (d50) of 4 nm with a volume of pores of 0.3 cm3g-1measured with the BJH method. 50 mg of Chlorhexidine diacetate (CAS 206986-79-0, ref C6143, SIGMA-Aldrich) is mixed with 50 mg of MESOPOROSIL® with 2.5 mL of a water-ethanol mixture with 70% ethanol. This mixture is stirred for 24 hours to ensure a deep penetration of the active ingredient in the pores.

[0062] After this contact time, the solid content is centrifuged twice at 6000 rpm for 10 minutes. The supernatant being then replaced first with fresh water-ethanol 70% mixture and then with demineralized water. The residue is then filtered and washed with demineralized water and dried 24 hours at 40°C in an oven.

[0063] 20 mg of loaded MESOPOROSIL is then added to 180 mg (10% wt) of a milled cholesterol powder (d50= 20 microns). This mixture is magnetically stirred in a beaker for 30 minutes to ensure a homogeneous distribution.

[0064] These 200 mg of powder are then poured into a HANDY 3.0 PERIO (ref: FT-221 , EMS Switzerland). The HANDY is operated dry with air only with 3 bars entry static pressure. The powder is sprayed with a rapid sweeping movement during 20 seconds on a glass plate (75 x 25 mm, VWR, 631 -1553) to cover a maximum surface. The nozzle to plate distance was 3 mm. Non-sticking powder on the glass is then removed with 3 bars compressed air.

[0065] The glass plate is then placed into 15 mL artificial saliva (ringer solution, Merk, 1.15525. 0001 ) and aliquots are taken regularly and measured with a standard HPLC method to determine the concentration of the active component in the solution.

[0066] Typical release profile is given below, indicating the percentage of active material released versus the total active material put in the initial mixture.

Claims

Claims1. Powder for use in treating tooth surfaces with a powder jet device, characterized in that the powder comprises(a) an organic compound in powder form, wherein the organic compound has a melting point of 35 - 170 °C and a solubility in water at 25 °C of < 10 g / l ,(b) a material in powder form having pores, comprising pores with a pore diameter < 50 nm, wherein the material has an average particle size d50< 50 pm, and(c) an active ingredient absorbed in the pores of the material.

2. Powder according to claim 1 , characterized in that the material comprises pores with a pore diameter < 20 nm.

3. Powder according to claim 1 or 2, characterized in that the average particle size of the material d50is < 20 pm, preferably < 10 pm.

4. Powder according to any of the preceding claims, characterized in that 90 % of the cumulative pore volume of the material are from pores with pore diameters < 20 nm, preferably < 15 nm.

5. Powder according to any of the preceding claims, characterized in that the melting point of the organic compound is 35 - 160 °C and / or the solubility of the organic compound in water at 25 °C is < 5 g / l.

6. Powder according to any of the preceding claims, characterized in that the organic compound is selected from the group consisting of fatty acids, fatty alcohols, sterols, hydroxy-substituted aromatic compounds and mixtures thereof.

7. Powder according to claim 6, characterized in that the fatty acid is selected from the group consisting of tridecanoic acid, pentadecanoic acid, palmiticacid, heptadecanoic acid, stearic acid, arachidic acid and mixtures thereof, and / or the fatty alcohol is selected from the group consisting of stearyl alcohol and lauryl alcohol, and / or the sterol is selected from the group consisting of cholesterol, beta-sistosterol and mixtures thereof and / or the hydroxy-substituted aromatic compound is selected from the group consisting of butylated hydroxytoluene (BHT), butylated hydroxy anisole (BHA) and mixtures thereof.

8. Powder according to any of the preceding claims, characterized in that the powder comprises(a) > 60 wt.-%, based on the total weight of the powder, of the organic compound and / or(b) < 30 wt.-%, based on the total weight of the powder, of the material in powder form having pores and / or(c) 0.1 to 10 wt.-%, based on the total weight of the powder, of the active ingredient.

9. Powder according to any of the preceding claims, characterized in that the material is silica and / or zeolite.

10. Powder according to any of the preceding claims, characterized in that the active ingredient is selected from the group consisting of pharmaceutically active compounds, tooth fluoridation agents, tooth remineralization agents and mixtures thereof, preferably selected from the group consisting of anti-inflammatory agents, anti-microbial agents, anti-bacterial agents, anti-viral agents, bone growth factors, tooth fluoridation agents, tooth remineralization agents and mixtures thereof.11 . Powder according to any of the preceding claims, characterized in that the powder comprises less than 5 wt.-% of a compound selected from the group consisting of sodium hydrogen carbonate, calcium carbonate, aluminium hydroxide, alditols, amino acids, sugars, cyclodextrins and mixtures thereof.

12. Powder according to any of the preceding claims, characterized in that the use in treating tooth surfaces with a powder jet device is a use in coating tooth surfaces with a powder jet device.

13. Coating on a tooth surface obtainable by applying the powder according to any of the preceding claims to a tooth surface with a powder jet device.

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