GB2461475A - Dental impression material - Google Patents

Abstract

An anti-microbial dental impression composition comprises at least one material capable of forming a cured dental impression material, an anti-microbial agent and a wetting agent. The composition may be provided as a kit of parts, wherein the antimicrobial agent and wetting agent are added to one or both parts of a two-part polymerisable material. The dental impression material may comprise silicones, polysulphides, polyethers, polyacrylics or alginates. The anti-microbial agent is preferable a silver-containing substance such as silver benzoate or a silver-containing, sodium calcium phosphate glass. The wetting agent is preferably an anionic wetting agent such as sodium lauryl sulphate. Moulded dental impressions formed from this composition are provided. The wetting agent improves the anti-microbial activity of the anti-microbial agent.

Description

DENTAL IMPRESSION MATERIAL

Field of the Invention

The present invention relates to a mold-taking material which is used for the preparation of oral models that are required in the preparation of dental prostheses in dentistry, such as crowns, inlays, onlays, bridges, implants and dentures (the mold-taking material being hereinafter referred to as "impression material") and in particular, to a dental impression material which exhibits anti-microbial activity.

Background of the Invention

A dental impression may be described as an accurate representation of part or all of a person's dentition and other areas of the mouth. From an imprint of a person's teeth, a dental impression forms a "negative" of those teeth and gums, which can then be used to make a cast or model of the dentition. This may be used for the fabrication of dentures, bridges, orthodontic appliances, crowns, bite registration records, occiusal balancing records or other prostheses. An impression is taken of the patient's mouth, or part of, in order that an accurate prosthesis can be made, or for studying the mouth itself.

Common materials used for dental impressions are sodium alginate, polyethers, polysuiphides, hydrocolloid materials, acrylics and silicones -both condensation-cured silicones and addition-cured silicones, such as polyvinyl siloxane. Silicone materials and waxes are used for bite registration and are usually harder than normal impression materials, usually having a Shore hardness in excess of 70. Impression materials used for other purposes are preferably elastic. Shore Hardness is measured according to ASTM D 2240.

The impression is normally sent to a specialist laboratory where it is needed in order to make the prosthesis or construct study models. The materials used are usually provided as two-part mixes or in the case of alginates as a single part.

The impression materials comprising alginates, silicone rubber, polyether rubbers or other suitable materials are usually mixed at the chair side.

An impression is usually carried out by placing a viscous liquid material into the mouth usually in a customised tray. The material then sets to become an elastic solid, and when removed from the mouth retains the shape of the dentition and/or gums.

Frequently, infective material and/or blood (which may be unknowingly infected) is present in the mouth and will contaminate the impressions. It is expected that the impressions will be sanitised immediately after they are taken in order to protect the dental surgery staff and those technicians at the laboratory who are likely to work with it. This sanitisation must take place before the impression is packaged for despatch and is currently done by spraying it with a disinfectant or placing the impression in a suitable solution, and then leaving it immersed for some considerable time. Such disinfection is inconvenient and unreliable, and in the case of hydrophobic materials such as silicone rubbers, is difficult to achieve. Some disinfection solutions are hazardous and foul smelling.

The impression will have many crevices and contours, etc. in which infectious material may reside and be difficult to disinfect properly. Air bubbles may be trapped under the surface of the sanitizing solutions with the area under the bubble remaining infective. Furthermore there is also a risk of infection being introduced to the patient from staff or instruments which may have been imperfectly cleansed.

US 6,495,613 mentions reducing the microbial count on dental tools and plastics, achieved by using anti-microbial substances and adhesion-reducing substances in the plastic used to take an impression. The anti-microbial agents are mixed into the impression material in the process of making it. However the means of adding in the adhesion-reducing substances relies upon either surface coating or mixing them in with a compatible solvent. This is impractical to use for an impression material. Furthermore these combined techniques may only reduce the adhesion of micro-organisms by 50% and destroy 60% of remaining organisms within an unacceptable period of 24 hours.

Flanagan et a! (1998, Dent Mater 14:399-404) describe anti-microbial alginate impression materials with quaternary ammonium compounds or chlorhexidine as anti-microbials. This system is not very effective, particularly in a short space of time, and is restricted to aqueous based systems.

US patent publication no. 2009/00476620A1 describes two-part, non- aqueous, polymerisable impression materials including a number of anti-microbial agents, and a method of use. The text of the document gives a microbiological test method, using one organism only, which does not provide the kill time" of the bacterium. Their method includes a rinse with sterile water after setting, which we have found to significantly reduce the number of organisms in itself but does not completely disinfect the material. Furthermore the contents of anti-microbial agents are quite high and are likely to affect the integrity of the impression.

The object of the present invention is to overcome the problems of the

prior art mentioned above.

The present invention addresses the problems of the effectiveness and speed of the anti-microbial action in the materials, the speed of the impression-taking process and despatch to the dental laboratory, and its applicability to aqueous and non-aqueous impression materials. It rapidly produces a sterile impression, thus reducing the possibility of cross-infection both in the dental surgery and the dental laboratory. Any subsequent accidental contamination will be sanitised by a reservoir of anti-microbial agent.

Summary of the Invention

In accordance with a first aspect of the invention, there is provided an anti-microbial dental impression composition comprising: (a) at least one material capable of forming a cured dental impression material; (b) a wetting agent; and, (c) an anti-microbial agent.

The at least one material capable of forming a cured dental impression material is preferably selected from the group consisting prepolymers or precursors for silicones, polyethers and polyacrylics; and alginates (and salts thereof), polyuronic acids (and salts thereof) and hydrophilic colloidal polysaccharides (and salts thereof).

In the context of the invention, "cured" means that the material capable of forming a dental impression material has been polymerised, set or otherwise hardened to form a dental impression product, preferably a final dental impression product. In this context, "final" means that the dental impression is not subject to any further processing steps which would materially affect its use as a working dental impression (such steps could include, for example, removing unwanted portions of the product, filing, cutting, etc.).

In accordance with a preferred embodiment of the first aspect of the invention, there is provided an anti-microbial dental impression composition comprising: (a) at least one polymerisable material composition; (b) a wetting agent; (c) an anti-microbial agent; (d) optionally a catalyst for the polymerisable material; and, (e) optionally, a solvent.

In accordance with the first aspect of the invention, component (a) may comprise a cross-linker compound for cross-linking the polymerisable material.

In accordance with another preferred embodiment of the first aspect of the invention, there is provided an anti-microbial dental impression composition comprising: (a) at least one composition comprising an alginate (or salt thereof), polyuronic acid (or salt thereof) or hydrophilic colloidal polysaccharide (or salt thereof); (b) a wetting agent; (c) an anti-microbial agent; and, (d) optionally, water.

In accordance with a second aspect of the invention, there is provided a kit of parts for producing a cured, anti-microbial, dental impression material comprising: (a) the first part of a two-part polymerisable material composition; (b) the second part of a two-part polymerisable material composition; (c) a wetting agent; (d) optionally a catalyst for the polymerisable material; and (e) optionally a solvent; and wherein an anti-microbial agent is incorporated in component (a), component (b), component (c), in both of components (a) and (b), in both of components (a) and (C), in both of components (b) and (C), or is presented as a separate component (f).

In accordance with the second aspect of the invention, component (a) may comprise a cross-linker compound for cross-linking the polymerisable material.

In accordance with the second aspect of the invention, component (b) may comprise a catalyst compound for catalysing the polymerisation of the first and second parts of the polymerisable material components (a) and (b).

In accordance with a third aspect of the invention, there is provided a kit of parts for producing a cured, anti-microbial, dental impression material, comprising: (a) at least one composition capable of forming a dental impression material; (b) a wetting agent; (c) optionally a catalyst for the dental impression composition; (d) optionally a solvent; and, wherein an anti-microbial agent is incorporated in component (a), component (b), in both of components (a) and (b), or is presented as a separate component (e).

In accordance with the third aspect of the invention, component (a) may comprise a cross-linker compound for cross-linking the polymerisable material.

In accordance with the third aspect of the invention, component (a) may comprise a catalyst compound for catalysing the polymerisation of the polymerisable material composition (a).

In the kit of parts, preferably, the anti-microbial agent and at least one of the polymerisable materials are presented together in a pre-formulated composition.

Preferably, the polymerisable material may be a one-part or two-part composition. Where it is a two part composition, the two components thereof may be presented separately.

In a fourth aspect of the present invention, there is provided a method for producing a dental impression material comprising: making a negative model of teeth and/or soft tissue using the above-described compositions or kits.

According to the fourth aspect of the invention, the method includes (a) mixing the material(s) capable for forming the cured dental impression material, with a second material which is capable of causing curing of the dental impression material; (b) making a negative model of teeth and/or soft tissue when the dental impression material is sufficiently viscous to allow moulding to the teeth and/or soft tissue; (c) allowing the material to cure or partially cure; and (d) removing the cured or partially cured material from the mouth.

An impression is usually carried out by placing a viscous liquid material into the mouth usually in a customised tray. The material then sets to become an elastic solid, and when removed from the mouth retains the shape of the teeth and surrounding tissue.

In a fifth aspect of the present invention, there is provided the use of a wetting agent to improve the anti-microbial activity of an anti-microbial agent when incorporated in a dental impression material.

In accordance with a sixth aspect of the invention, there is provided a moulded dental impression comprising: (a) at least one dental impression material selected from the group consisting of silicones, polysulphides, polyethers, polysilicones, alginates (and salts thereof), polyuronic acids (and salts thereof) and hydrophilic colloidal polysaccharides (and salts thereof); (b) a wetting agent; (c) an anti-microbial agent; (d) optionally a filler material; and, (e) optionally, one or more adjuvant materials selected from the group consisting of solvents, diluents, plasticizers, pigments, dyes, thixotropic agents, indicators, inhibitors, stabilizers and UV absorbers.

In accordance with a seventh aspect of the present invention, there is provided a moulded dental impression of a dental occlusion, said dental impression comprising a composition according to any of the preceding aspects of the invention, said dental impression having a Shore hardness exceeding 70 for the purposes of bite registration, preferably between 70 and 250.

The addition of one or more anti-microbial agents to the precursor materials of impression materials, with a wetting agent, enables microbial contamination to be destroyed preferably within 5 minutes of the contamination taking place.

Without being bound by theory, it is postulated that, at the micro level, particles of the anti-microbial need to make contact at the surface with, or dissolve out of the surface and make contact with the microbial cells, in the presence of moisture. If the material of the impression is hydrophobic, water will not wet the surface sufficiently to allow this to happen. Even more surprisingly, it has been found that the addition of a wetting agent promotes rapid and sufficient release of anti-microbial materials from hydrophilic and hydrophobic materials, so as to improve the rapidity of 100% kill. It is postulated that a microscopic film of material covers anti-microbial particles at the surface of the impression. Such films are normally permeable to an extent, but insufficiently so to allow antimicrobial agent to permeate out and make contact rapidly with microbial cells. A wetting agent causes greater wetting with aqueous fluids and will cause greater permeation through thin films. This will allow a lower concentration of anti-microbial agent to be used and to diffuse more rapidly from the surface of the impression material.

Detailed Description of the Invention

The Dental Impression Polymers Preferably the polymerised or cured dental impression material is hydrophobic or hydrophilic. The polymerisable non-polymeric and/or oligomeric precursors to the dental impression material may or may not be hydrophobic.

All dental impression materials may be used in the present invention.

These include agar hydrocolloids, alginates, acrylic rubbers, polysulfide rubbers, polyether rubbers, silicone rubbers, and the like, including both conventional and proprietary materials. These impression materials are preferably elastic. This property is required as such materials need to be suitable for impression taking of complicated forms having an undercut in the oral cavity, such as tooth roots, dentitions, jaws, and mucous membranes, because the deformation generated upon being removed out from the oral cavity must be quickly recovered.

As used herein "hydrophobic" means surfaces on which water will form separated drops having a contact angle of greater than 750, preferably greater than 80°, more preferably greater than 90°, for example, greater than 100°, 1100, 120°, 130°, 140° or 150°. In short, hydrophobic materials are non-wettable or poorly wettable. The above mentioned contact angle is measured at 30 seconds after wetting and at 25°C, and is carried out on a flat, smooth, horizontal surface of the material.

By contrast, the term "hydrophilic" is characterized by the fact that water will spread on the surface. A hydrophilic material is a material upon which water will form a contact angle of less than 45°, preferably less than 20°. The above mentioned contact angle is measured at 30 seconds after wetting and at 25°C, and is carried out on a flat, smooth, horizontal surface of the material.

In a preferred embodiment, the dental impression polymer is selected from alginates (and salts thereol, silicones, polyethers and polysulphides.

A particularly preferred polymer material is a silicone. Conventional silicone materials may be used. Examples of suitable silicone materials include those disclosed in WO 00/48553, US 2005/027032, US 3,950,300, US 4,035,453, US 5,907,002, and US 5,064,891, the contents of which are incorporated herein by reference.

Silicone rubber compositions offer several advantages over materials used as a dental replica material, e.g., plaster, alginate, etc. As compared with plaster, silicone rubber is more elastic, has better resistance to breakage and offers good release from the jaw. As compared with alginates, silicone rubber is not sensitive to loss of water (which may cause shrinkage) and possesses better moulding accuracy. Silicones also provide good dimensional stability which is retained even on prolonged storage in the air (For reference, see "Chemistry and Technology of Silicones", Walter NoD, Academic Press, New York, 1968, p. 623.). Polyether and polysulphide impression materials offer similar advantages.

Silicone impression materials are preferably what are referred to as "two-part" compositions. Such two part compositions preferably comprise two components (1) a basal composition, which preferably contains silicone polymer precursor(s), a crosslinker and optionally a filler, and (2) a catalyst composition, which preferably contains silicone polymer precursor(s), a catalyst and optionally a filler. The materials are hardened after mixing has taken place in pre-defined volume ratios which are readily determined by the skilled person (and are routinely quoted in literature associated with commercially available materials).

The basal composition and/or the catalyst composition of a two part silicone composition are preferably provided in the form of pastes. Preferably, these are mixed shortly before the impression is to be taken.

Some preferred cross-linking agents for the silicone polymer precursors include phenyl triethoxy silane, vinyl triethoxysilane, n-propyl silicate and condensed ethyl orthosilicate.

The cross-linker is preferably present in an amount of from about 0.05 to about 10 weight %, more preferably 0.1 to 2 weight % of the silicone precursor compounds.

The anti-microbial agents may be part of the premix in a concentration so as to give a made up concentration in the range 0.01 to 10%, preferably 0.05 to 5%, preferably 0.1 to 2%, preferably 0.2 to 1% based on the total amount of silicone materials.

The precursors are preferably mixed manually or by being ejected from double-chamber cartridges, with the pastes being conveyed through a mixing tube which contains a static mixer. Automatic, motor-driven mixing and metering systems for two-component impression materials are also available and may be used. For example, such systems are disclosed in US 5,286,105.

Examples of preferred alginate materials are disclosed in JP1 1209215, JP11209217, JP2304011, US4810295 and US5698610, the content of which is incorporated herein by reference. Conventional alginate materials are preferably used.

Alginate or hydrocolloid impression materials (aqueous based) are made up usually using a premixed powder and adding water. The amount of water added will depend on the type of material used and is usually stated as a volume to be added to a specified weight of the starting powder. For example, for the commercially available Hydrogum5-Zhermack�, the ratio is 3Oml water to 14g dry powder; for commercially available Alginate Fast Set-Henry Schein�, it is 1 part water to 3 parts by volume of dry powder. Substantially all, and preferably all of the make-up water is retained in the impression.

A preferred alginate material is sodium alginate.

Alginate is usually a linear copolymer with homopolymeric blocks of (1- 4)-linked 13-D-mannuronate and its C-5 epimer a-L-glucuronate residues, respectively, covalently linked together in different sequences or blocks.

The anti-microbial agents may be part of the premix in a concentration so as to give a made up concentration in the range 0.01 to 10%, preferably 0.05 to 5%, preferably 0.1 to 2%, preferably 0.2 to 1% based on the final weight of the alginate or hydrocolloid impression materials when mixed with an appropriate amount of water.

Some hydrocolloid systems are provided as ready-made-up products which are warmed before use.

Examples of preferred polyether-based impression materials are disclosed in WO 2008/014224, us 5,849,812 us 4,877,845 and US 5,849,812, all of which are incorporated herein by reference. Conventional polyether materials may be used.

Polyether-based impression materials are preferably "two-part" compositions. Such two part compositions preferably comprise two components (1) a basal composition, which preferably contains polyether polymer precursor(s), a crosslinker and optionally a filler, and (2) a catalyst composition, which preferably contains polyether polymer precursor(s), a catalyst and optionally a filler. The production of polyether-based impression materials is preferably analogous to that of the silicone polymer impression materials.

The Anti-Microbial Agent The term anti-microbial agent" as used herein includes a substance, such as a compound, element or an ion, that is capable of destroying or inhibiting the growth and/or proliferation of a microorganism, such as, an anti-bacterial agent, an anti-fungal agent, an anti-viral agent, and/or an anti-parasitic agent. An anti-microbial agent may be a composition produced by or derived from certain bacteria, fungi, plants, and other organisms, and derivatives and variants thereof. An anti-microbial agent may also be synthesized or semi-synthesized chemically. In one embodiment, an anti-microbial agent may be a salt, a small molecule organic compound, a lipid, a carbohydrate, a polypeptide, a nucleic acid, a mineral compound, or combinations thereof.

Examples of anti-microbial agents include, without limitation, acyclovir, amphotericin B, ampicillin, atovaquone, azithromycin, bacitracin, carbomycin, cephalosporin, chloramphenicol, chlorotetracyclin, ciprofloxacin, clarithromycin, clindamycin, clofazimine, cycloheximide, dapsone, diclazaril, doxycycline, erythromycin, ethambutol, fluconazole, fluoroquinolones, foscarnet, fumigillin, ganciclovir, gentamicin, griseofulvin, iatroconazole, kanamycin, ketoconazole, lincomycin, methicillin, miconazole, neomycin, ofloxacin, oleandomycin, paromomycin, penicillin, pentamidine, polymyxin-B, pyrazinamide, pyrimethamine, rifabutin, rifampicin, rifamycin, spartloxacin, streptomycin, sulfadiazine, tetracycline, trifluorouridine, vancomycin, and Zn-pyrithione, as well as heavy metals, their compounds and salts thereof including, without limitation, copper, gold, platinum, silver, zinc, boron and antimony, as well as mineral compounds, such as silver zeolites; and combinations of any of the above thereof including, e.g., salts, such as chloride, bromide, iodide, and periodate, and complexes with carriers, and other forms.

In one highly preferred embodiment, the anti-microbial agent may be a silver-containing, anti-microbial agent, such as, without limitation, a silver- containing compound or complex, or a silver nanoparticle. Various silver-containing anti-microbial agents suitable for the purposes of the present invention are known in the art, such as, those disclosed in US Patent Nos. 7,160,553; 6,897,349; 6,605,751; 6,355,858; 5,928,174; 5,833,665; and 5,196,190, and US Patent Publication Nos. 2007/0003603; 2005/0226931, 2001/0041188.

Particularly preferred anti-microbial agents that may be used include, but are not limited to, certain metals and compounds or metal containing glasses (silver and silver compounds, copper and copper compounds, zinc and zinc compounds; silver, copper and zinc glasses including sol-gel derived glasses); quaternary ammonium compounds, chlorhexidine and its salts, phenolic compounds and antibiotics. Preferably, such materials are water-soluble to a lesser or greater extent.

As used herein, the meaning of water-soluble will be known to the skilled person. However, a preferred water-solubility may be obtained by suitable adjustment of the glass composition, and the dissolution rates in static water at 38°C preferably range from substantially 0.001 mg/cm2/hour to 25 mg/cm2/hour, more preferably 0.005 mg/cm2/hour to 10 mg/cm2/hour.

The preferred anti-microbial agents are the metals and compounds, and the metal-containing glasses, most preferably silver, silver compounds, and silver containing glasses. Suitable silver and other metal containing glasses are disclosed in European patents EP0379507, EP 0809506, EP1094992, EP1087914 and US 6,143,318 and are preferably sodium calcium phosphate glasses containing the respective metal, prepared by a pyrotechnic method.

Other suitable metal-containing glasses are disclosed in US 6,482,444 and are bioactive calcium phosphate silicate glasses containing the respective metal, prepared by a sot-gel method.

The invention is not limited to these particular glasses as other types may be used. In the case of metal elements, they may be nano metals. The anti-microbial agents are normally incorporated as dry fine powder or a liquid.

According to a particularly preferred embodiment of the present invention, the anti-microbial agent is a water-soluble, silver-containing glass materiaL Typically the soluble glasses used in this invention comprise phosphorus pentoxide (P205) as the principal glass-former, together with any one or more glass-modifying non-toxic materials such as sodium oxide (Na20), potassium oxide (K20), magnesium oxide (MgO) and calcium oxide (CaO). The rate at which the silver-release glass dissolves in fluids is determined by the glass composition, generally by the ratio of glass-modifier to glass-former and by the relative proportions of the glass-modifiers in the glass. By suitable adjustment of the glass composition, the dissolution rates in water at 38°C ranging from substantially zero to 25 mg/cm2/hour or more can be produced.

The water-soluble glass is preferably a phosphate glass, and the silver may advantageously be introduced during manufacture as silver orthophosphate (Ag3PO4). The content of silver and other constituents in the glass can vary in accordance with conditions of use and desired rates of release, the content of silver generally being up to 10% by weight.

An exemplary water-soluble glass composition contains: P205: 3oto6omole%; Na20: 3Oto6Omole%; and K20:5tolsmole%; Ag203: 0 to 5 mole %; and optionally may contain: B203: 0 to 15 mole %; and/or NaF: 0 to 5 mole %; and/or Si02: 0 to 5 mole %; and/or total alkaline earth metal compounds: 0 to 5 mole %.

A highly preferred water-soluble glass composition contains: P205: 40 to 60 mole %; B203: Oto 10 mole %; Na20: 30 to 40 mole %; K20: 5to 10 mole %; Ag20: 0 to 5 mole %; Si02: 0 to 5 mole %; and up to 5 mole % of other additive compounds such as CaD, MgO and ZnO.

Other compounds may also be added to the glass to modify its properties, for example Si02, A1203, SO3, MgO, CaO, ZnO, sulphate ions or transition metal compounds (e.g. first row transition metal compounds), but these will preferably be present in low quantities, for example up to a total amount of 5 mole % or less of the glass composition.

Preferably Si02 is added to the glass compositions in up to 5 mole % based on the weight of the glass composition.

Particularly preferred glasses used as the anti-microbial material in all aspects of the present invention are sodium calcium phosphate glasses having the CAS references 7440-50-8, 7440-66-6, 7440-22-4. These materials have the brand names Corglaes copper, Corglaes zinc and Corglaes silver respectively.

The anti-microbial material may be incorporated in the dental impression composition in an amount of 0.01% to 10%, preferably 0.02 to 5%, preferably 0.05 to 3%, preferably 0.1 to 2% by weight based on the weight of the final product, as used by the dental practitioner.

Two-part systems (normally non-aqueous) comprise a base paste (BP) and a catalysing paste or viscous liquid (CPL) which are mixed in the necessary proportions in the dental surgery. The anti-microbial agents are placed in one or both parts of the product, preferably in BP, in a concentration which will provide the concentrations as mentioned above.

The Wetting Agent The inclusion of one or more wetting agents in the compositions and kits of the present invention accelerates the destruction of microbial contamination, particularly in non-aqueous systems by causing the surface of the impression to be wetted by water more easily, such water being present from saliva, tissue fluid, or dental flushing systems.

Wetting agents are preferably used in an amount of 0.1 to 5%, preferably 0.5 to 3%, preferably 1 to 2.5%, for example, about 1, 1.5, 2 or 2.5% based on the weight of the final product.

The wetting agent may be cationic, anionic, amphoteric or non-ionic.

Mixtures of these wetting agents can also be used. Preferred wetting agent compositions comprise anionic wetting agents or mixtures of anionic wetting agents with other wetting agents, especially nonionic wetting agents.

Suitable wetting agents for use with the present invention include, but are not limited to, sarcosinates, glutamates, sodium alkyl suiphates, ammonium alkyl sulphates, ammonium alkyleth sulphates, ammonium laureth-n-sulphates, sodium laureth-n-sulphates, isothionates, glycerylether sulphonates, sulfosuccinates and combinations thereof. In some embodiments, the composition of the present invention includes a wetting agent selected from the group consisting of sodium lauroyl sarcosinate, monosodium lauroyl glutamate, sodium alkyl sulphates, ammonium alkyl sulphates, sodium alkyleth suiphates, and combinations thereof.

Nonlimiting examples of wetting agents useful herein include the conventional C11-C8 linear or branched alkyl benzene sulphonates and primary, secondary, linear, branched and random alkyl sulphates, the C10-C18 alkyl alkoxy sulphates, the C10-C18 alkyl polyglycosides and their corresponding sulphated polyglycosides, C12-C18 alpha-sulphonated fatty acid esters, C12-C18 alkyl and alkyl phenol alkoxylates (especially ethoxylates and mixed ethoxy/propoxy), C12-C18 betaines and sulfobetaines ("sultaines"), C10-C18 amine oxides, and the like.

Other anionic wetting agents include the isethionates such as the acyl isethionates, N-acyl taurates, fatty acid amides of methyl tauride, alkyl succinates and sulfosuccinates, monoesters of sulfosuccinate (especially saturated and unsaturated C12-C18 monoesters) diesters of sulfosuccinate (especially saturated and unsaturated C6-C14 diesters), N-acyl sarcosinates.

Resin acids and hydrogenated resin acids are also suitable, such as rosin, hydrogenated rosin, and resin acids and hydrogenated resin acids present in or derived from tallow oil.

Anionic sulphate wetting agents suitable for use herein include the linear and branched primary and secondary alkyl sulphates, alkyl ethoxysulphates, fatty oleoyl glycerol sulphates, alkyl phenol ethylene oxide ether sulphates, the C5-C17 acyl-N-(C1 -C4 alkyl) and -N-(C1-C2 hydroxyalkyl) glucamine sulphates, and sulphates of alkylpolysaccharides such as the sulphates of alkylpolyglucoside.

Alkyl sulphate wetting agents are preferably selected from the linear and branched primary C10-C18 alkyl sulphates, more preferably the C11-C15 branched chain alkyl suiphates and the C12-C14 linear chain alkyl sulphates.

Alkyl ethoxysuiphate wetting agents are preferably selected from the group consisting of the C10-C18 alkyl suiphates which have been ethoxylated with from 0.5 to 20 moles of ethylene oxide per molecule. More preferably, the alkyl ethoxysulphate wetting agent is a C11-C18, most preferably C11-C15 alkyl sulphate which has been ethoxylated with from 0.5 to 7, preferably from 1 to 5, moles of ethylene oxide per molecule.

Anionic sulphonate wetting agents suitable for use herein include the salts of C5-C20 linear or branched alkylbenzene sulphonates, alkyl ester sulphonates, C6-C22 primary or secondary alkane sulphonates, C6-C24 olefin sulphonates, sulphonated polycarboxylic acids, alkyl glycerol sulphonates, fatty acyl glycerol sulphonates, fatty oleyl glycerol sulphonates, and any mixtures thereof.

Suitable anionic carboxylate wetting agents include the alkyl ethoxy carboxylates, the alkyl polyethoxy polycarboxylate wetting agents and the soaps (alkyl carboxyls'), especially certain secondary soaps as described herein.

Particularly preferred wetting agents include sodium or ammonium C10-C18 alkyl sulphates, sodium or ammonium C10-C18 alkoyl sarcosinate, stearalkonium halide, PEG stearates and cetrimonium halide.

Particularly preferred wetting agents include sodium lauryl sulphate, sodium ricinoleate, sodium lauroyl sarcosinate, stearalkonium chloride, PEG stearates and cetrimonium chloride.

Sodium lauryl sulphate is a particularly preferred wetting agent. It is preferably used in an amount of 0.1 to 5%, preferably 0.5 to 3%, preferably 1 to 2.5%, for example, about 1, 1.5, 2 or 2.5% based on the weight of the dental impression material precursors.

The wetting agent is normally incorporated in the impression material (or its precursor(s)) as a dry fine powder or as a liquid in the impression material.

In the case of alginate materials, which are normally provided as dry powder mixtures, made up in the surgery with added water, the antimicrobial active agent may be added in dry form to the powder mixture at the time of manufacture in an amount necessary to give the desired concentration in the final wet product used by the dental surgeon.

The anti-microbial agent may be provided as a separate container of powder or in a base powder or liquid mix to be added to the mix at the chair side. It is also possible to provide the anti-microbial agent in a concentrated base paste, to be mixed in at the chair side.

In the case of products which are provided in two or more parts for mixing at the chair side by mixing these reactive pastes, such as silicones, polyether rubbers and polysulphides, the anti-microbial agent may be mixed into one part only, in an amount necessary to give the desired concentration in the final product as used, or into both parts.

The wetting agent may be provided as a separate container of liquid or in a base powder or liquid mix to be added to the mix at the chair side. It is also possible to provide the wetting agent in a concentrated base paste, to be mixed in at the chair side.

The wetting agent may be incorporated in the same part as the anti-microbial active agent, and/or in one or both parts (where a two part composition is present) of the polymerisable material(s) composition (s).

In practice, an important aspect of any two-part, polymerisable preparation made using this technology is that the setting time of the made up impression material should not be changed significantly by the addition of the anti-microbial or wetting agents.

This is determined by the time to commencement of polymerisation after mixing, which should be not less than 0.5x and not more than 2x the time achieved without the added components, more preferably between 0.7x and 1.4x. Also important is the time between mixing the components and the end of polymerisation, which should not change by less than 0.5x and 2x, more preferably between 0.7x and 1.4x.

For example for Alginate Fast Set� the mixing and working time is about seconds and the setting time is about 60 seconds. For Hydrogum 5� the mixing and working time is about 90 seconds and the setting time is about 45 seconds. For Fresh Putty (Dreve�), a vinylpolysiloxane, the processing time is +1-30 seconds and the setting time is 180 +1-60 seconds. For lmpregum (3M Espe�), a polyether, the processing time is about 165 seconds and the setting time is about 195 seconds.

Preferred Compositions Some exemplary compositions according to the present invention include the following: 1. An anti-microbial dental impression composition comprising: (a) 50-98 weight % of a polymerisable material composition; (b) 0.1 to 10 weight % ofawetting agent; (c) 0.01 to 10 weight % of an anti-microbial agent; (d) 0 to 5 weight % of a catalyst for the polymerisable material; and (e) 0 to 45 weight % of a solvent.

2. An anti-microbial dental impression composition comprising: (a) 70-98 weight % of a polymerisable material composition comprising a polymer precursor material selected from silicone, polyether and polysulphide precursors; (b) 0.5 to 5 weight % of a wetting agent selected from anionic and non-ionic wetting agents; (c) 0.1 to 2 weight % of a silver based anti-microbial agent; (d) 0 to 5 weight % of a catalyst for the polymerisable material; and (e) 0 to 30 weight % of a solvent.

3. An anti-microbial dental impression composition comprising: (a) 80-98 weight % of a polymerisable material composition comprising a polymer precursor material selected from silicone precursors; (b) 1 to 3 weight % of a wetting agent selected from anionic and non-ionic wetting agents; (c) 0.1 to 2 weight % of a anti-microbial agent comprising a water-soluble, silver-containing glass material; (d) 0.01 to 0.5 weight % of a catalyst for the polymerisable material; (e) 0 to 20 weight % of a solvent.

Component (a) in any of the immediately preceding compositions 1 to 4 may contain not only the polymer precursor materials, but also cross-linking agent(s), filler(s) and/or catalysts.

4. An anti-microbial dental impression composition comprising: (a) 20-65 weight % of an composition comprising an alginate (or salt thereof), polyuronic acid (or salt thereof) or hydrophilic colloidal polysaccharide (or salt thereof); (b) 0.1 to 10 weight % of a wetting agent; (c) 0.01 to 10 weight % of an anti-microbial agent; and (d) 30 to 75 weight % water.

5. An anti-microbial dental impression composition comprising: (a) 25-50 weight % of an alginate (or salt thereof) composition; (b) 0.5 to 5 weight % of a wetting agent selected from anionic and non-ionic wetting agents; (c) 0.1 to 2 weight % of a silver based anti-microbial agent; and, (d) 45 to 70 weight % water.

The kit compositions of the present invention may comprise equivalent quantities of components to the above-mentioned compositions.

Some exemplary final product compositions according to the present invention include the following: 6. An anti-microbial dental impression composition comprising: (a) 20 to 90 weight % of a polymer; (b) 0 to 70 weight % of a filler material; (c) 0.1 to loweight%ofawetting agent; (d) 0.1 to 10 weight % of an anti-microbial agent; (e) 0 to 20 weight % of a one or more adjuvant materials selected from the group consisting of solvents, diluents, plasticizers, pigments, dyes, thixotropic agents, indicators, inhibitors, stabilizers and UV absorbers.

7. An anti-microbial dental impression composition comprising: (a) 40 to 70 weight % of a polymer; (b) 20 to 50 weight % of a filler material; (c) 0.1 to 5 weight % of a wetting agent; (d) 0.1 to 5 weight % of an anti-microbial agent; (e) 0 to 10 weight % of a one or more adjuvant materials selected from the group consisting of solvents, diluents, plasticizers, pigments, dyes, thixotropic agents, indicators, inhibitors, stabilizers and UV absorbers.0 to 20 weight % of a solvent.

8. An anti-microbial dental impression composition comprising: (e) 20 to 90 weight % of a composition comprising a precursor for an alginate (or salt thereof), polyuronic acid (or salt thereof) or hydrophilic colloidal polysaccharide (or salt thereof); (f) 0 to 70 weight % of a filler material; (g) 0.1 to 10 weight % of a wetting agent; (h) 0.1 to 10 weight % of an anti-microbial agent; (e) 0 to 20 weight % of a one or more adjuvant materials selected from the group consisting of solvents, diluents, plasticizers, pigments, dyes, thixotropic agents, indicators, inhibitors, stabilizers and UV absorbers.

9. An anti-microbial dental impression composition comprising: (a) 40 to 80 weight % of an alginate (or salt thereof); (b) 10 to 50 weight % of a filler material; (c) 0.1 to 5 weight % of a wetting agent; (d) 0.1 to 5 weight % of an anti-microbial agent; (e) 0 to 10 weight % of a one or more adjuvant materials selected from the group consisting of solvents, diluents, plasticizers, pigments, dyes, thixotropic agents, indicators, inhibitors, stabilizers and UV absorbers.0 to 20 weight % of a solvent.

The kit compositions of the present invention may comprise equivalent quantities of components to the above-mentioned compositions.

Other components Where catalyst is present, it is preferably present in an amount of from 0.01 parts of catalyst to 5 weight % of the polymerisable polymer precursor(s).

For example, the catalyst may be present in an amount of from 0.025-3 weight %, more preferably 0.1-1 weight % of the polymerisable polmyer precursor(s).

Such catalysts are routinely used in silicone, polyether and polysulphide impression material production.

Catalysts suitable for the present dental impression compositions are conventional and well known. Metal salts of monocarboxylic acids have been found to be effective. Various acid radicals and metal ions are suitable as components in the metal salts. Some preferred acid radicals are the linoleate, stearate, oleate, acetate, butyrate and octoate. Tin is especially preferred for the metal ion because of its low toxicity. Some preferred metal salts are tin oleate, tin butyrate and tin octoate. Especially preferred is tin octoate.

Fillers may be incorporated into the silicone compositions of the present invention. For example, the filler may be selected from the group consisting of zinc oxide, calcium carbonate, pumice and mixtures thereof.

Where more than one filler material is present, the various components of the filler can be selected to work in combination. Calcium carbonate and zinc oxide can be used as bulking as well as whitening agents. Pumice can be used to provide a putty-like consistency to the composition. Pumice is also more easily wetted into the formulation and thus assures more consistency from batch to batch than other types of filler.

Preferably, a filler material may be present in an amount of 5 to 75 weight %, preferably 10 to 50 weight %, more preferably 15 to 25 weight % based on the silicone polymer precursor(s).

The molding compositions of the invention can contain a wide variety of adjuvants depending upon the desired end use. Suitable adjuvants include solvents, diluents, plasticizers, pigments, dyes, inorganic or organic fibrous or particulate reinforcing or extending fillers, thixotropic agents, indicators, inhibitors, stabilizers, UV absorbers, leachable fluorides and the like.

Solvent, where present, may be selected from organic solvents, water or mixtures thereof. Preferred solvents are non-volatile or of low volatility. The use of the solvent preferably does not cause shrinkage of the moulded impression.

As the above solvents, there may be mentioned, for example, hydrocarbon solvents such as ether type solvents such as diethyl ether, tetrahydrofuran and diphenyl ether; ketone type solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; alcohol type solvents such as methanol, ethanol, propanol, isopropanol, n-butyl alcohol and tert-butyl alcohol; and ester type solvents such as ethyl acetate and butyl acetate; and the like.

These may be used singly or two or more of them may be used in admixture.

Preferably, the solvent is non-toxic. The solvent may be present in an amount of 0.1-80 weight%, preferably 5-50 weight % of the dental impression material precursors.

Any of the kits of parts referred to herein (especially in respect of two part compositions) may additionally comprise one or more measuring receptacles (such as a scoop having a predefined volume, or collapsible tubes having predefined quantities of materials therein).

General The term "comprising" encompasses "including" as well as "consisting" e.g. a composition "comprising" X may consist exclusively of X or may include something additional e.g. X + Y. The term "about" in relation to a numerical value x means, for example, x+10%.

The word "substantially" does not exclude "completely" e.g. a composition which is "substantially free" from Y may be completely free from Y. Where necessary, the word "substantially" may be omitted from the definition of the invention.

As used herein, "the final product" means a polymerised dental impression material including any of the stated mandatory and optional components referred to herein. Thus, when a particular component of a composition is referred to as being quantified in terms of "% by weight of the final product", this is intended to mean that it is present in the stated % based on all of the components present in the final moulded dental impression product.

As used herein, the terms "silicones", "polyethers", "polyacrylics" and "polysilicones" are intended to cover homopolymers, copolymers and terpolymers of the stated polymers.

Examples of the Present Invention The following examples of the present invention are merely exemplary and should not be viewed as limiting the scope of the invention

Example 1

Sufficient silver glass (0.088g) of the sodium calcium phosphate type and sodium lauryl sulphate was mixed into 14g of a commercially available alginate impression material powder (Hydrogum 5�) and 30 ml water so as to give a content of 0.2% of the glass and 1% of the sodium lauryl sulphate in the final impression material, which was made up with the required amount of water. The mixture was cast into a sheet approximately 2mm thick from which discs approximately 15mm in diameter were cut.

Discs were tested as follows for anti-microbial activity. A disc was placed on the surface of a tryptone soya agar microbiological growth medium seeded with Streptococcus mutans culture and incubated at 35°C. No growth of the organism occurred under the disc and in a zone measuring 7mm around the disc. A disc prepared and tested in a similar fashion but without adding anti-microbial agent showed no inhibition of growth.

Example 2

Discs prepared as in Example 1 were tested as follows: Droplets of known volume, of S. mutans culture of known colony forming units per millilitre were sandwiched between two discs for measured times of 5, 10 and 20 minutes. After these times the respective discs were separated and the contact sides pressed onto a tryptone soya agar medium plate which was then incubated for 48 hours. Any colonies grown were to be counted. However no colonies were grown on the plates from all time periods.

Example 3

Discs were prepared using a proprietary two-part, polymerisable, silicone impression material (Dreve Dentamid�). Sufficient silver glass and sodium lauryl sulphate were mixed into one part to achieve a content of 0.5% of the glass and 2.5% of the sodium lauryl sulphate in the made up material. The discs were tested as in Example 1. No growth occurred under the disc and in a zone measuring 3mm around the disc.

Example 4

Silicone discs were prepared as in Example 3 and tested as in Example 2. No colonies were grown on the plates from all time periods.

Example 5

Alginate discs were prepared and tested as in Example 1 but using 0.2% silver benzoate as the anti-microbial agent and with no sodium lauryl sulphate. There was no growth under the disc and in a zone measuring 1.5mm around the disc.

This demonstrates the beneficial effect of the sodium lauryl sulphate wetting agent used in Example 1.

Example 6

Silicone discs were prepared and tested as in Example 3 but using 1% silver benzoate as the anti-microbial agent and no sodium lauryl sulphate. There was no inhibition of microbial growth, showing the necessity of using a wetting agent with this percentage content in silicone impression material which is highly hydrophobic.

Example 7

Silicone discs were prepared as in Example 3 with the range of contents of silver glass at 0, 0.1, 2.0, 5.0, and 10.0% by weight of the final product, and with no sodium lauryl sulphate. These were tested as in Example 3 against Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans.

The 0 and 0.1% discs did not inhibit growth of any organism.

The 2.0% disc inhibited growth of all except C albicans.

The 5.0 and 10.0% discs inhibited growth of all organisms, however inhibition was limited to the medium under the disc and there was no zone of inhibition around the disc. This shows how, although activity can be achieved without using a wetting agent, this can be obtained only by using very high levels of anti-microbial agent.

Example 8

Silicone discs were prepared as in Example 3 but containing no anti-microbial agent or wetting agent, and tested as in Example 2 but included a rinse with sterile water after the contact with the culture and before incubation. The count of colony forming units applied to the discs was 6.24x10(6) and after incubation was 150 at the 5 minute time and 1200 at the 30 minute time.

This demonstrates that rinsing alone removes microbial contamination. Relevant to the test method used in US patent publication No. 2009/00476620.

Other compositions will suggest themselves to those skilled in the art in view of the above-detailed descriptions. All such obvious variations are within the full intended scope of the invention, which is defined in the appended claims.

The following table lists some of the commercially available dental impression materials which can be used in the present invention.

Substance CAS Registry No. Source Reference vinyl polysiloxane 0 J Prosthet Dent 1 982;47(4) :411 Triad� 108570-51-0 J Prosthet Dent 1 989;61 (5) :583 Impregum� 0 Br Dent J 147(1 2) :331;1979 Jeltrate� 67924-61 -2 J Prosthet Dent 1984;52(4):479 Polysulfide rubber 63148-67-4 Cah Prothese 11:144; 1975 Permadyne mt J Prosthodont 1995 Mar-Premier� 0 Apr;8(2):129-34 president�, silicone impression J Philipp Dent Assoc 1998 Mar-material 0 May;49(4):37-49 Ultrafine� 94363-16-3 J Prosthet Dent 1984;52(4):479 mt j Prosthodont 1996 Jul-Extrude� 0 Aug;9(4):367-73 J Prosthet Dent 2003 Oct;90(4) :354-aguasil� 0 64 lnzoma� 82497-06-1 Dtsch Zahnarztl Z 1982;37(10):815 Provil� 0 J Prosteth Dent 1991;65(2):244 Dentaflex� 0 Khirugiia (Sofiia) 1987;40(5):27 mt j Prosthodont 2004 Sep-Permadyne� 0 Oct;17(5):585-9 81536-56-3 Relate� Relate J Prosthet Dent 1981;46(4) :380 Surgident� 94363-11-8 J Prosthet Dent 1984;52(4):479 Dent-Kate� 1221 68-66-5 J Prosthet Dent 1988;59(6):739 Coe Alginate� 101706-70-1 J Prasthodont 1994 Dec;3(4) :219-27 Bite Registration Paste� 0 J Prosthodont 1994 Sep;3(3):134-7 Hydrogum� 0 J Prosthodont 1995 Sep;4(3):195-9 Mortite� 80595-71 -7 J Prosthet Dent 1981;46(2):215 Rubberloid� 94363-06-1 J Prosthet Dent 1984;51 (6):797 Schweiz Monatsschr Zahnmed Impresept espe� 0 1996;106(1 1):999-1 002 MACH 2� 0 Dent Today 1996 May:15(5):82-5 Permadyne mt J Prosthodont 2004 Sep-garant� 0 Oct;17(5):590 Myoprint� 81 536-55-2 J Prosthet Dent 1981;46(4):380 New Kromopan� 0 J Prostet Dent 1991;65(2):244 lntJ Prosthodont 1991 Jul-Kromgel� 0 Aug;4(4):382-7 mt J Prosthodont 1994 Mar-Fastray� 61970-27-2 Apr;7(2):1 29-33 Sorbanat� 0 Dent Mater 1996 Mar;12(2):74-82

Claims (21)

1. Claims 1. An anti-microbial dental impression composition comprising: (a) at least one material capable of forming a cured dental impression material; (b) a wetting agent; and, (c) an anti-microbial agent.
2. 2. A composition according to claim 1, wherein the material capable of forming a cured dental impression material is selected from the group consisting of prepolymers for silicones, polysulphides, polyethers and polyacrylics; and alginates (and salts thereof), polyuronic acids (and salts thereof) and hydrophilic colloidal polysaccharides (and salts thereof).
3. 3. A composition according to claim 1, wherein the material capable of forming a cured dental impression material is a polymerisable material composition.
4. 4. A composition according to claim 1, wherein the material capable of forming a cured dental impression material is an alginate (or a salt thereof) composition.
5. 5. A kit of parts for producing a cured, anti-microbial, dental impression material, comprising: (a) at least one composition capable of forming a dental impression material; (b) a wetting agent; (c) optionally a catalyst; (d) optionally a solvent; and, wherein an anti-microbial agent is incorporated in component (a), component (b), in both of components (a) and (b), or is presented as a separate component (e).
6. 6. A kit of parts for producing a cured, anti-microbial, dental impression material comprising: (a) the first part of a two-part polymerisable material composition; (b) the second part of a two-part polymerisable material composition; (c) a wetting agent; (d) optionally a catalyst; and (e) optionally a solvent; and wherein an anti-microbial agent is incorporated in component (a), component (b), component (c), in both of components (a) and (b), in both of components (a) and (c), in both of components (b) and (C), or is presented as a separate component (f).
7. 7. A method for producing a dental impression material comprising: making a negative model of teeth and/or hard tissue using the compositions or kits defined in any preceding claim.
8. 8. Use of a wetting agent to improve the anti-microbial activity of an anti-microbial agent when incorporated in a cured dental impression material.
9. 9. A moulded dental impression comprising: (a) at least one cured dental impression material selected from the group consisting of silicones, polysulphides, polyethers, alginates (and salts thereof), polyuronic acids (and salts thereof) and hydrophilic colloidal polysaccharides (and salts thereof); (b) a wetting agent; (c) an anti-microbial agent; (d) optionally a filler material; and, (e) optionally, one or more adjuvant materials selected from the group consisting of solvents, diluents, plasticizers, pigments, dyes, thixotropic agents, indicators, inhibitors, stabilizers and UV absorbers.
10. 10. A moulded dental impression according to claim 9, wherein the cured dental impression material is hydrophobic.
11. 11. A composition, method, use, kit of parts or a moulded dental impression according to any preceding claim, wherein the anti-microbial agent is an anti-bacterial agent.
12. 12. A composition, method, use, kit of parts or a moulded dental impression according to any preceding claim, wherein the anti-microbial agent is selected from the group consisting of acyclovir, amphotericin B, ampicillin, atovaquone, azithromycin, bacitracin, carbomycin, cephalosporin, chloramphenicol, chiorotetracyclin, ciprofloxacin, clarithromycin, clindamycin, clofazimine, cycloheximide, dapsone, diclazaril, doxycycline, erythromycin, ethambutol, fluconazole, fluoroquinolones, foscarnet, fumigillin, ganciclovir, gentamicin, griseofulvin, iatroconazole, kanamycin, ketoconazole, lincomycin, methicillin, miconazole, neomycin, ofloxacin, oleandomycin, paromomycin, penicillin, pentamidine, polymyxin-B, pyrazinamide, pyrimethamine, rifabutin, rifampicin, rifamycin, sparfioxacin, streptomycin, sulfadiazine, tetracycline, trifluorouridine, vancomycin, and Zn-pyrithione, as well as heavy metals, their compounds and salts thereof including, copper, gold, platinum, silver, zinc, boron and antimony, as well as mineral compounds, such as silver zeolites; and combinations of any of the above thereof including, e.g., salts, such as chloride, bromide, iodide, and periodate, and complexes with carriers, and other forms.
13. 13. A composition, method, use, kit of parts or a moulded dental impression according to any preceding claim wherein the anti-microbial agent is a silver-containing glass.
14. 14. A composition, method, use, kit of parts or a moulded dental impression according to claim 13, wherein the glass is a water-soluble, silver-containing, sodium calcium phosphate glass.
15. 15. A composition, method, use, kit of parts or a moulded dental impression according to any preceding claim, wherein the anti-microbial is present in the dental impression composition in an amount of 0.01% to 10%, preferably 0.02 to 5%, preferably 0.05 to 3%, preferably 0.1 to 2% by weight based on the weight of the final product.
16. 16. A composition, method, use, kit of parts or a moulded dental impression according to any preceding claim, wherein the wetting agent is present in an amount of 0.1 to 5%, preferably 0.5 to 3%, preferably 1 to 2.5%, for example, about 1, 1.5, 2 or 2.5% based on the weight of the final product.
17. 17. A composition, method, use, kit of parts or a moulded dental impression according to any preceding claim, wherein the wetting agent is selected from one or more of cationic, anionic, amphoteric or non-ionic wetting agents, preferably anionic wetting agents.
18. 18. A composition, method, use, kit of parts or a moulded dental impression according to any preceding claim, wherein the wetting agent is selected from the group consisting of sodium lauroyl sarcosinate, monosodium lauroyl glutamate, sodium alkyl sulphates, ammonium alkyl suiphates, sodium alkyleth sulphates, and combinations thereof.
19. 19. A composition, method, use, kit of parts or a moulded dental impression according to any preceding claim, wherein the wetting agent is selected from the group consisting of sodium lauryl sulphate, sodium ricinoleate, sodium lauroyl sarcosinate, stearalkonium chloride, PEG stearates and cetrimonium chloride.
20. 20. A method of making a dental prostheses using a moulded dental impression according to claim 9.
21. 21. The method of claim 19, wherein the prostheses is a crown, inlay, onlay, implant, bridge or dentures.