Dental material based on alkoxysilyl-functional polyethers containing a salt of a strong acid as catalyst

The present invention relates to condensation-cross-linking dental materials, especially condensation-cross-linking two-component dental materials, on the basis of alkoxysilyl-functional polyethers containing at least one alkoxysilyl-functional polyether as well as at least one catalyst, wherein the at least one catalyst is a salt formed from a weak organic base whose PKBH+ value measured in water is between −1 and 7 and at least one strong acid whose pKs value measured in water is lower than 2 and which preferably has a structure that permits mesomeric stabilization of the negative charge after deprotonation of the acid.

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Description

The present invention relates to condensation-cross-linking dental materials, especially condensation-cross-linking two-component dental impression materials, based on alkoxysilyl-functional polyethers, which are suitable in particular for taking impressions, and to use of same. Such materials are used in dental medicine for purposes such as taking teeth impressions, bite registration, relining dental prostheses, temporary and permanent dental cement, temporary sealing material or dental duplicating material.

Known condensation-cross-linking dental materials usually contain hydroxyl-functional polymers with a silicone backbone, which cure in the presence of organotin compounds as catalysts, alkoxysilanes and/or silicic acid esters as cross-linking agents and water. However, such materials are relatively hydrophobic because of the silicone backbone of the polymer, and so considerable quantities of surfactants must be added to them in order to lower the surface tension and to adjust the necessary wettability. A further disadvantage of these compositions lies in the use of toxicologically questionable tin compounds as catalyst.

As alternatives thereto there are known two-component dental materials, which contain polymers having terminal alkoxysilyl groups and a hydrophilic polyether backbone, and which exhibit sufficiently hydrophilic properties for wetting the moist tooth substance. Usually these materials are composed of a base component containing alkoxysilyl-functional polyethers that have an average molecular weight of 800 to 20,000 g/mol and that can also contain urea and/or urethane groups depending on the synthesis, fillers and possibly other additives, and of a catalyst component which, besides fillers and possibly other auxiliary substances, contains an organic and/or inorganic acid as catalyst.

From European Patent 0269819 B1 there are known condensation-cross-linking two-component dental materials whose base components contain polyaddition products containing alkoxysilyl end groups and having a predominantly linear molecular structure and an average molecular weight of 800 to 20,000 g/mol, which have a content of polyether groups of 25 to 90 wt %, a content of urethane groups of 0.5 to 10 wt %, a content of urea groups of 0.5 to 10 wt % and a content of terminal alkoxysilyl groups of 1 to 25 wt %, and whose catalyst components have a mixture containing water as well as organic and/or inorganic acids in weight ratios (water/acid) of 1:0.01 to 1:40. However, the synthesis of the base component containing functional polyether polymers is very complex and expensive. A further disadvantage of these dental materials lies in the use of acid-containing catalysts. Firstly, the acid catalysts can harm the oral mucosa and the enamel by acid etching during molding in the patient's mouth. In addition, these systems do not permit any addition of nitrogen-base-containing substances, such as astringents, for example epinephrine, or other acid-labile therapeutic additives, since these are inactivated by the acid catalyst due to protonation or cleavage. Furthermore, the use of acids in production of the dental materials necessitates appropriate safety precautions.

European Patent 1226808 A2 discloses condensation-cross-linking two-component dental materials composed of a base component and catalyst component, the base component of which contains alkoxysilyl-functional polyethers with linear or branched main chain and an average molecular weight of 800 to 20,000 g/mol, which have a content of polyether groups from 20 to 95 wt %, a content of terminal alkoxysilyl groups from 0.2 to 25 wt % and possibly a content of urethane groups or urea groups of up to 10 wt %, and whose catalyst components have a mixture containing water as well as organic and/or inorganic acids in weight ratios of 1:0.01 to 1:40. Preferably the catalyst component contains p-toluenesulfonic acid as catalyst as well as a polyether diol and further additives, such as fillers, paraffin, emulsifier and the like. Certainly the functional polyether polymers used in these dental materials can be synthesized more easily and cheaply than those cited hereinabove, and they are characterized by better setting kinetics. However, these dental materials also make use of acid-containing catalysts, so that on the one hand the risk of harm to the oral mucosa as well as the enamel exists during molding in the patient's mouth and, moreover, no acid-labile therapeutic additives can be mixed in with these materials. A further disadvantage of the systems lies in their poor storage stability. However, a setting time that is constant regardless of storage time is one of the most important requirements of a dental impression material.

In International Patent WO 99/18912, the use of metalloorganic compounds such as iron or tin compounds, for example tin(II) octate, or of tertiary amines such as triethylamine, is proposed for cross-linking of polyurethanes to be used as adhesives or sealants and containing polyether groups. A disadvantage of these catalysts, however, lies in their high toxicity, and so suitable safety precautions have to be taken in production of the materials, and use of the materials as dental impression compounds is not possible without further precautions. In addition, tertiary amines in particular are strong-smelling, and so the use thereof in dental materials is not desirable. Furthermore, the polyurethanes used in these materials are characterized by strong intermolecular interactions because of their high content of urethane groups per molecule, and this, in view of the given chain length of the molecules, leads to higher viscosity of the materials compared with alkoxysilyl-functional polyethers, which have only two urethane groups per molecule, and so only low contents of fillers can be used in these materials, in turn causing increased manufacturing costs.

Furthermore, from European Patent 1402873 A1 there is known a two-component formulation, which sets at room temperature as an elastomeric material, and in which there is contained, in catalyst component B, an organic or inorganic acid and, in base component A, a silane-functionalized polyether derivative as well as a compound with antacid effect, the compound with antacid effect being chosen from groups composed of the basic or amphoteric oxides, hydroxides, carbonates, carboxylates and basic organic compounds with N, As, O, P, S or Sb as the hetero atom as well as nitrogen-containing compounds with isocyanate, epoxide, carbodiimide or aziridine groups.

The object of the present invention is therefore to provide a hydrophilic condensation-cross-linking dental material, especially a condensation-cross-linking two-component dental impression material on the basis of alkoxysilyl polyethers, which material is stable during storage, in particular has constant reaction kinetics even after at least 18 months of storage time, has good biocompatibility, in particular is neutral as to smell as well as taste, and contains constituents that are toxicologically as safe as possible.

According to the invention, this object is achieved by a condensation-cross-linking dental material of the composition according to claim 1.

In connection with the present invention, it was surprisingly found that the salt catalysts to be used according to the invention have good catalytic activity for condensation reactions and are therefore eminently suitable for being used as catalyst in condensation-cross-linking dental materials based on alkoxysilyl-functional polyethers. The inventive dental materials not only have reaction kinetics that are suitable for dental materials but in particular also exhibit practical processing and setting times. Consequently, compared with substances known heretofore for this purpose, such as metalloorganic compounds and tertiary amines, these catalysts are distinguished by good biocompatibility and are subject to less rigid safety precautions during preparation of the dental materials. In particular, the use of heavy-metal catalysts, such as organotin, organozinc or organolead catalyst compounds, can be dispensed with. A further advantage of the salt catalysts used according to the invention, especially compared with the primary, secondary and tertiary amines known from the prior art, lies in their neutral smell and taste, which is an important property for a dental impression material, in order to achieve acceptance by the patients and, for example, to avoid gagging reactions of the patients during application. In addition, it was unexpected for the person skilled in the art that such dental materials exhibit reaction kinetics that remain constant, especially constant processing and setting times, even after several months of storage. This is due among other factors to the fact that, during the storage period and after curing, the catalyst salts used according to the invention do not enter into any side or degradation reactions with other constituents, such as the fillers, the polyethers that may be used as paste-forming agents or the alkoxysilyl polyethers. Aside from this, compared with the use of a free acid and a free base, such as a tertiary amine, the use of a salt as catalyst is also advantageous because the salt has a relatively moderate pH, thus ensuring good compatibility of the inventive dental materials with the oral mucosa and with the enamel, meaning that no burning or irritation occurs during application.

The inventive dental materials can be formulated both as one-component material and as two-component material. Whereas the formulation of the one-component dental materials must be as absolutely anhydrous as possible in order to prevent a reaction of the alkoxysilyl-functional polyethers during storage, and the reaction of the alkoxysilyl polyethers after application of the materials on the object from which the impression is to be taken is initiated by atmospheric moisture, water is preferably added to the catalyst component of the inventive two-component dental material. Preferably the two-component dental materials are formulated such that

    • base component A contains
      • a) at least one alkoxysilyl-functional polyether,
    • and catalyst component B contains
      • b) at least one catalyst and
      • c) water,
    • the at least one catalyst b) being a salt formed from a weak organic base whose PKBH+ value measured in water is between −1 and 7 and at least one strong acid whose pKs value measured in water is lower than 2.

According to a first special embodiment of the present invention, the at least one catalyst is a salt formed from a weak organic base whose PKBH+ value measured in water is between −1 and 7 and at least one strong acid whose pKs value measured in water is lower than 2, the acid having a structure that permits mesomeric stabilization of the negative charge after deprotonation of the acid. Mesomeric stabilization as used in the present invention means, in agreement with general textbook knowledge, that at least two limiting structures in which the negative charge is localized on different atoms can be formulated for the deprotonated acid, or that π electrons are delocalized in the deprotonated acid, leading to stabilization of the deprotonated form.

Regardless of whether the inventive dental material is formulated as a one-component or two-component system, the catalyst salt used is preferably formed from at least one acid whose pKs value measured in water is smaller than 1 and particularly preferably smaller than or equal to 0.7 and/or at least one base whose PKBH+ value measured in water is between 1 and 7, particularly preferably between 2 and 6 and quite particularly preferably between 3 and 6.

According to a further special embodiment of the present invention, the at least one catalyst salt is formed from an acid chosen from the group comprising p-toluenesulfonic acid, fluorosulfonic acid, trifluoromethanesulfonic acid, fluorosulfuric acid, 4-sulfophthalic acid, trichloroacetic acid, trifluoroacetic acid, benzenesulfonic acid and combinations thereof and/or from a base selected from the group comprising pyrrole derivatives, dimethylaniline, pyridine, 2,4,6-N,N-pentamethylaniline, N,N-dimethylaniline, phenetedine, acridine, phenanthridine, quinoline, isoquinoline, 2-amino-4,6-dimethylpyrazine, 4,6-dimethylpyridinamine, 3-methylpyridine (3-picoline), 4-phenylpyridine, 4-vinylpyridine, pyridazine, 2-ethylpyridine, 2-butylpyridine, 1,7-phenanthroline, 2-aminopyrimidine, 2-isopropylpyridine, 2-vinylpyridine, 2-N,N-dimethylaminopyridine, quinazoline, 4-chloropyridine, phenazine, 4-acetylpyridine, methyl nicotinate, 3-benzoylpyridine, 2,2′-bipyridine, 2-phenylpyridine, 2-tert-butylpyridine, pyrimidine, 3-iodopyridine, 3-fluoropyridine, 3-chloropyridine, 3-bromopyridine, pyrazine, 7,8-benzoquinoline, 2-chloropyridine, 4-cyanopyridine and combinations thereof. Particularly preferably, there is used as catalyst a salt of p-toluenesulfonic acid with pyridine or a salt of p-toluenesulfonic acid with 2,4,6-N,N-pentamethylaniline.

In an improvement of the inventive idea, it is proposed that the cations and/or acid anions provided in the catalyst salts to be used according to the invention contain alkoxysilyl groups. Thereby it is achieved that the catalyst salt is bound in the polyether matrix after curing of the dental material and can no longer be dissolved out of the dental impression material.

According to the invention, the dental materials can contain, as catalyst, one or more of the aforesaid salts in any desired combination with one another. Preferably the dental material contains only one of the aforesaid salts as catalyst and, particularly preferably, no further catalysts, especially no metalloorganic metal salts, tertiary amines or free acids, are used besides the one or more salts to be used according to the invention.

Preferably there is used in the inventive dental material a catalyst salt b) whose pH measured in water (Ampuwa, pH 5.8) is between 1 and 7, particularly preferably between 2 and 6 and quite particularly preferably between 2 and 5.

As the person skilled in the art is aware, the quantity of catalyst salt to be used depends among other factors on the solubility of the salt in the polyether matrix used. Preferably the quantity of catalyst salt to be used, relative to the total mixture of the dental material, is 0.0005 to 0.5 mmol/g, particularly preferably 0.0005 to 0.25 mmol/g and quite particularly preferably 0.0005 to 0.05 mmol/g. Obviously the catalyst salt used must have a minimum solubility in the polyether matrix used, in order to be able to act catalytically at all.

In order to keep the quantity of catalyst salt to be used as small as possible, it is proposed in an improvement of the inventive idea that a catalyst salt with sufficiently high solubility in the polyether material, or in other words with adequate catalytic activity, be used in the dental material, the catalytic activity being characterized within the meaning of the present patent application by the curing time according to ISO 4823 (1992 edition), determined by recovery after deformation. Preferably there is used a catalyst salt that, in a polyether matrix comprising as structural units polytetrahydrofuran, polyethylene glycol and particularly preferably polypropylene glycol as well as mixtures and copolymers thereof, yields a curing time of less than or equal to 30 minutes, particularly preferably less than or equal to 15 minutes for a dental duplicating compound and a curing time of less than or equal to 15 minutes, particularly preferably less than or equal to 10 minutes, quite particularly preferably less than or equal to 7 minutes and most preferably less than or equal to 6 minutes for a dental impression compound.

If the inventive dental material is formulated as a one-component material, it should be as absolutely anhydrous as possible, in order to avoid a reaction of the alkoxysilyl-functional polyether during storage.

In the case that the dental material is formulated as a two-component material, catalyst component B preferably contains water c), whereas base component A is as absolutely anhydrous as possible. Preferably catalyst component B of the inventive two-component dental material contains, relative to the total mixture, 0.005 to 3 mmol/g, particularly preferably 0.01 to 2 mmol/g and quite particularly preferably 0.02 to 1 mmol/g of water.

Preferably the inventive dental material contains at least one reinforcing filler d1) and/or at least one non-reinforcing filler d2). In formulation as a two-component material, base component A can contain at least one of the aforesaid fillers, preferably at least one reinforcing filler and/or at least one non-reinforcing filler being provided both in base component A and in catalyst component B.

Suitable as reinforcing fillers d1) are in particular highly disperse, active fillers with a BET surface of at least 50 m2/g and/or a primary particle size of smaller than or equal to 100 nm, particularly preferably smaller than or equal to 80 nm. Particularly suitable are those that have a primary particle size in the nanometer range and that can exist as aggregates and/or agglomerates. Preferably the at least one reinforcing filler d1) is a substance selected from the group comprising aluminum hydroxide, zinc oxide, titanium dioxide, zirconium dioxide and silicon dioxide as well as precipitated and/or pyrogenic silicas. Obviously the aforesaid compounds can be used individually or in any desired combinations with one another and, in fact, both in hydrophilic and in hydrophobed form.

Furthermore, the at least one reinforcing filler d1) is present in the form of nanoparticles, as fibrous or flaky filler, such as mineral, fibrous filler, or as synthetic, fibrous filler.

As an improvement of the inventive idea, it is proposed that, in formulation as two-component material, there be provided, preferably in base component A, reinforcing fillers d1) having a water content of at most 0.5 wt %, particularly preferably of at most 0.3 wt %, quite particularly preferably of at most 0.15 wt % and most preferably being absolutely or substantially anhydrous, the water content being determined by Karl Fischer titration.

According to a further special embodiment of the present invention, the at least one reinforcing filler d1) with a BET surface of larger than 50 m2/g in base component A has a pH of 4 to 11, preferably of 5 to 9 and particularly preferably of 5.0 to 8.5.

In formulation as a two-component system, base component A preferably contains, relative to component A, 0 to 50 wt %, particularly preferably 0.1 to 40 wt % and quite particularly preferably 0.1 to 30 wt %, and catalyst component B preferably contains, relative to component B, 0 to 50 wt %, particularly preferably 0.1 to 40 wt % and quite particularly preferably 0.1 to 30 wt % of at least one reinforcing filler d1).

As non-reinforcing fillers d2), the same substances as for reinforcing fillers b1) are in principle suitable, although the non-reinforcing fillers necessarily have a BET surface of smaller than 50 m2/g (Schriftenreihe Pigmente Degussa Kieselsäuren [Publication Series Pigments Degussa Silicas], number 12, page 5 as well as number 13, page 3). Preferably the at least one non-reinforcing filler d2) is a substance selected from the group comprising alkaline earth oxides, alkaline earth hydroxides, alkaline earth fluoride, alkaline earth carbonates, calcium apatite (Ca5[(F,Cl,OH 1/2CO3)|(PO4)3], especially calcium hydroxyapatite (Ca5[(OH)|(PO4)3]), titanium dioxide, zirconium oxide, aluminum hydroxide, silicon dioxide, precipitated silica and calcium carbonate. Obviously the aforesaid compounds can be used individually or in any desired combinations with one another and, in fact, both in hydrophilic and in hydrophobed form.

Preferably the non-reinforcing fillers d2) used have an average particle size of larger than 0.1 μm (Ullmann's Encyclopedia of Industrial Chemistry, Volume 21, page 523).

As an improvement of the inventive idea, it is proposed in formulation of the dental material as a two-component system that the at least one non-reinforcing filler d2) in base component A have a water content of at most 0.5 wt %, particularly preferably at most 0.1 wt %, quite particularly preferably at most 0.05 wt % and, most preferably, be absolutely or substantially anhydrous.

According to a special embodiment of the present invention, the at least one non-reinforcing filler d2) in base component A has a pH of 4 to 11, preferably of 5 to 9 and particularly preferably of 5.0 to 8.5.

Base component A of the inventive dental material preferably contains, relative to component A, 0 to 80 wt %, particularly preferably 0.05 to 75 wt % and quite particularly preferably 0.1 to 70 wt %, and catalyst component B preferably contains, relative to component B, 0 to 80 wt %, particularly preferably 0.05 to 75 wt % and quite particularly preferably 0.1 to 70 wt % of at least one non-reinforcing filler d2).

In an improvement of the inventive idea, it is proposed that, in formulation as a two-component material, the reinforcing and/or non-reinforcing fillers contained in catalyst component B have a pH of between 2.0 and 7.0 and quite particularly preferably such with a pH of between 3.0 and 7.0.

On the whole, the total content of fillers, both in formulation of the dental material as a one-component and as a two-component system, is 0 to 80 wt %, preferably 0.01 to 80 wt %, particularly preferably 0.1 to 75 wt % and quite particularly preferably 0.2 to 70 wt % relative to the total mixture.

As alkoxysilyl-functional polyethers a) there can be used in principle all polyethers containing alkoxysilyl groups, and the polyether backbone can be linear and/or branched and, for example, can be composed of polyethylene oxide, polypropylene oxide, polytetrahydrofuran and/or copolymers thereof, while these monomers can be present statistically, in blocks or in a tactic arrangement. As starters for the polyethers and/or copolymers there can be used monohydric or polyhydric alcohols, such as methanol, butanol, glycerin, trimethylpropane, pentaerythritol and sorbitol. For example, copolymers of polytetrahydrofuran with polyethylene oxide or of polyethylene oxide and polypropylene oxide can be used, polypropylene oxide being particularly preferred. Furthermore, there are preferred polyethers with side alkyl groups, wherein every or at least every tenth monomeric structural unit has a side alkyl group. Suitable commercial products are Acclaim 4200, Acclaim 6320N, Acclaim 12200, Acclaim 8200 and Acclaim 6300 of Bayer AG, Polyglycol P11/300 and Polyglycol P413000 (Clariant) as well as poly(ethylene glycol-ran-propylene glycol) (Aldrich). Polyethers a) preferably have a number-average molecular weight of 500 to 25,000 g/mol and particularly preferably of 5,000 to 20,000 g/mol.

Besides the chain length (elasticity), the alkoxysilyl functionalization (curing kinetics) and the number of urethane/urea groups (viscosity, rheology), a selection criterion for polyethers that are suitable according to the invention is the hydrophilicity of the polyether, which is determined via the number, structure and polarity of the monomeric repeating units of the polyether polymer. The hydrophilicity of a dental impression material must on the one hand be sufficiently high to ensure good flow onto moist dental substance (low contact angle), but on the other hand the material must not be too hydrophilic, since otherwise water, moisture or saliva leads to swelling during the taking of an impression or during disinfection or during production of a plaster cast, and so the necessary dimensional accuracy is no longer assured. Beyond this, the hydrophilicity of the polyether is also responsible for the solubility, among other properties, of the inventive catalyst.

According to a particular embodiment of the present invention, the at least one alkoxysilyl-functional polyether has a content of polyether groups of between 5 and 30 mmol/g and particularly preferably of between 10 and 25 mmol/g.

Preferably the alkoxysilyl structural unit or the alkoxysilyl structural units of polyether a) is or are disposed in terminal position relative to the polymer backbone and are given by the general formula I
—SiR5R6R7

    • in which R5, R6 and R7 independently of one another are alkoxy, alkyl, aryl, aralkyl, alkylaryl groups or hydrogen, preferably butoxy, propoxy, ethoxy, methoxy, hexyl, pentyl, butyl, propyl, ethyl or methyl groups, particularly preferably ethoxy, methoxy, ethyl or methyl groups, with the proviso that at least one of the aforesaid groups, preferably two or all three groups, are alkoxy groups.

In an improvement of the inventive idea, it is proposed that the at least one polyether a) have an alkoxy group content of 0.02 to 12 mmol/g, particularly preferably of 0.04 to 6 and quite particularly preferably of 0.04 to 3 mmol/g.

By means of the type and number of alkoxy groups per silicon atom, it is possible to adjust the condensation kinetics and thus the processing and setting times of the dental material. These parameters are preferably chosen in such a way that the processing time is 30 seconds to 3 minutes, particularly preferably between 1 and 2.5 minutes and quite particularly preferably between 1.5 and 2 minutes and/or the setting time in the patient's mouth (known as the mouth removal time), determined according to ISO 4823 (1992 edition), is at most 15 minutes, particularly preferably at most 10 minutes, quite particularly preferably at most 7 minutes and most preferably 6 minutes.

The at least one polyether a) preferably contains, as a third structural unit (besides the terminal alkoxy groups and the polyether groups), alkylene spacers, which are disposed on each of the terminal alkoxysilyl groups and which are preferably C1 to C6 alkyl groups, particularly preferably C1 to C3 alkyl groups, quite particularly preferably ethylene groups and/or methylene groups and most preferably methylene groups.

In addition, the at least one polyether a) can contain, as a fourth structural unit, 0 to 8 mmol/g, particularly preferably 0 to 4 mmol/g, quite particularly preferably 0.02 to 2 mmol/g and most preferably 0.1 to 0.4 mmol/g of urethane groups and/or 0 to 8 mmol/g, particularly preferably 0 to 2 mmol/g, quite particularly preferably 0.02 to 2 mmol/g and most preferably 0.1 to 0.4 mmol/g of urea groups. Particularly when the at least one polyether a) contains urea and/or urethane groups as the fourth structural unit, a methylene group is preferred as spacer. By the use of such α-activated alkoxysilyl polyethers there are obtained hydrophilic, storage-stable two-component dental impression compounds, which become cross-linked surprisingly rapidly by condensation reaction with a salt to be used according to the invention as catalyst. On the whole, the content of urethane or urea groups per molecule should be kept as low as possible, in order to minimize intermolecular interactions between the individual polyether chains, in order to keep the viscosity caused by the polyether addition as low as possible, thus permitting the addition of larger quantities of fillers in the dental material and in turn imparting more margin for formulation and achieving more cost-effective recipes.

Within the scope of the present invention, it has proved advantageous to use polyethers that contain no urethane or urea groups within the polyether chain and that have at each chain end at most/not more than one urethane or urea group and at most/not more than one (alkoxy)silyl group and at most/not more than one methylene spacer group. Compared with the polyurethane-alkoxysilyl polyethers used in the prior art, the use of these polyethers leads to formulations with lower viscosity, so that more fillers can be added to the dental materials, thus leading to a reduction of production costs.

According to a further particular embodiment of the present invention, the individual structural units of the at least one polyether a) are arranged as follows:

    • in which R1, R2 and R3 independently of one another are alkoxy, alkyl, aryl, aralkyl, alkylaryl groups or hydrogen, preferably butoxy, propoxy, ethoxy, methoxy, hexyl, pentyl, butyl, propyl, ethyl or methyl groups, particularly preferably ethoxy, methoxy, ethyl or methyl groups, with the proviso that at least one of the aforesaid groups, preferably two or all three groups, are alkoxy groups, as well as
    • x=1 to 6, preferably x=2 to 4 and quite particularly preferably x=2, n=1 to 6, preferably n=1 to 3 and quite particularly preferably n=1, as well as m=0 or 1, particularly preferably m=1,
    • or
    • in which R1, R2 and R3 independently of one another are alkoxy, alkyl, aryl, aralkyl, alkylaryl groups or hydrogen, preferably butoxy, propoxy, ethoxy, methoxy, hexyl, pentyl, butyl, propyl, ethyl or methyl groups, particularly preferably ethoxy, methoxy, ethyl or methyl groups, with the proviso that at least one of the aforesaid groups, preferably two or all three groups, are alkoxy groups, as well as
    • x=1 to 6, preferably x=2 to 4 and quite particularly preferably x=2, n=1 to 6, preferably n=1 to 3 and quite particularly preferably n=1, as well as l=0 or 1, particularly preferably l=1,
      According to a further particular embodiment of the present invention, the alkyl spacer in the aforesaid structural units is methylene (n=1).

The synthesis of these alkoxysilyl-functional polyethers is known and is described in, for example, German Patent 10104079 A1, European Patent 0629819 B1, German Patent 10139132, U.S. Pat. No. 4,906,707, European Patent 0372561 A1, European Patent 1303560 A1 and European Patent 0170865 B1, which are introduced here as reference and are valid as part of the disclosure. Examples of polyethers that are commercially available and suitable within the scope of the present invention are MS Polymer S 203H, MS Polymer S 303H (Kaneka), Polymer XP ST55, ST50, ST51, ST53 (Hanse), SLM 414000 (Wacker), SLM 414001 (Wacker), Baycoll XP 2458 and Desmoseal XP 2447 (Bayer AG), the dimethoxy(methyl)silylmethyl-carbamate-terminated polyether:
sold under the trade name SLM 414000, and the dimethoxy(methyl)silylmethyl-urea-terminated polyether:
being particularly preferred.

In an improvement of the inventive idea, it is proposed that one or more of the following additives or auxiliary agents be added to the inventive dental material:

    • f) thixotropic agent,
    • g) water scavenger,
    • h) paste-forming agent,
    • i) surfactant,
    • j) active agent,
    • k) plasticizer,
    • l) substance permitting optical scanning,
    • m) flavor and/or fragrance,
    • n) substance permitting diagnostics,
    • o) fluoridating agent,
    • p) bleaching agent,
    • q) desensitizing agent,
    • r) bond promoter,
    • s) dye,
    • t) indicator,
    • u) stabilizer (antioxidant, radical scavenger).

Thixotropic agent f) can be added optionally to the inventive dental material, and high molecular weight polyethers in particular, such as polyethylene glycol, polyethylene glycol/polypropylene glycol copolymers, polytetrahydrofuran, hydrocarbon waxes, amide waxes, triglycerides, silicas and silicates have proved particularly suitable for this purpose.

According to a particular embodiment of the present invention, the dental materials, when formulated as a two-component system, preferably contain in base component A at least one water scavenger g), which particularly preferably is selected from the group comprising alkoxysilanes, titanates, such as tetraisopropyl titanate, zirconates, such as tetrapropyl zirconate, zeolites, aluminum sulfate, anhydrous calcium sulfate (such as Drierite®), blue gel and/or oxazolidines.

In an improvement of the inventive idea, it is proposed that one or more functional alkoxysilanes be used as water scavenger g), since the cross-linking rate, the structure and the properties of the resulting elastomer can be additionally adjusted by such compounds. Preferably the at least one functional alkoxysilane is a compound of general formula II
R84-x—Si—R9x

    • with R8=H, alkyl, alkenyl, —(CH2)n-Z, where n=1 to 6,
    • R9=alkoxy,
    • Z=NH2, NHR, NR2, where R=alkyl, aminoalkyl, —C(CO)OCH3, as well as x=1, 2, 3 or 4,
    • where particularly preferably R8=alkenyl, especially vinyl, or —(CH2)n-Z with Z═NHR and n=1 or 3, particularly n=1, and/or x=3 and/or R═—C(O)OCH3.

Particularly preferably, the at least one functional alkoxysilane g) is vinyltrimethoxysilane, N-trimethoxysilylmethyl-O-methyl carbamate and/or a compound of the following formula:

    • in which n=1 to 6, preferably n=1 or 3, particularly preferably n=1, d=0 or 1, and
    • R10=a linear or branched C1 to C30 alkyl group, in which some of the hydrogen atoms may be substituted by halogen atoms, OH—, NH2—, NO2— or even other C1 to C6 alkyl groups.

The aforesaid compounds are reactive silanes, which function as water scavengers to eliminate any traces of water still present from component A of the dental composition.

Furthermore, the inventive two-component dental materials preferably contain, and particularly preferably, in fact, when formulated as a two-component system, at least one paste-forming agent h) in catalyst component B, since this permits the adjustment of a paste-like consistency, for example of low viscosity, medium viscosity or high viscosity, as well as homogeneous mixing of the salt and of the solid reinforcing and non-reinforcing fillers. Preferably there is used as the at least one paste-forming agent h) a compound selected from the group comprising polyethers, polyvinylpyrrolidones, polyurethanes, polyesters, waxes, vaselines, paraffin oils, silicone oils, polyhydric alcohols, propylene glycols, polypropylene glycols, ethylene glycols, polyethylene glycols, copolymers of N-vinylpyrrolidone and vinyl acetate, carboxymethyl-, methyl-, hydroxyethyl-, hydroxypropylcellulose, polysaccharides, glycerin and poly(meth)acrylic acids. Obviously the inventive dental materials may also contain any desired combination of two or more of the aforesaid compounds.

Particularly preferred are hydrophilic paste-forming agents, in which the inventive catalyst salt can be mixed homogeneously with water. The miscibility can be further improved by addition of surfactants. Particularly preferred representatives are polyethers, polyurethanes, polyesters, polyhydric alcohols, particularly propylene glycols, polypropylene glycols, ethylene glycols, polyethylene glycols, butylene glycols, polybutylene glycols and glycerin as well as mixtures and copolymers thereof.

The compounds i) that may be used as surfactant, emulsifier and/or stabilizer are preferably anionic surfactants, particularly preferably alkyl sulfates, alkylbenzenesulfonates or alkylbenzene phosphates, cationic surfactants, particularly preferably tetraalkylammonium halides, nonionic surfactants, particularly preferably alkyl and alkylphenyl polyalkylene oxides, fatty acid alkoxylates, fatty alcohol alkoxylates as well as alkyl ethers and alkyl esters thereof, fatty acid alkylolamides, sucrose fatty acid esters, trialkylamine oxides, silicone surfactants (such as Silwet L77, Tegopren 5878) or fluorosurfactants, or amphoteric surfactants, particularly preferably sulfated or oxyethylated condensation products of alkenylphenols and formaldehyde, ethylene oxide/propylene oxide block polymers or modified polysiloxanes. Advantageously there can also be used surfactants that can be incorporated by polymerization into the alkoxysilyl-functional polyethers a), as disclosed in U.S. Pat. No. 4,160,778, which is introduced here as reference and is valid as part of the disclosure. In addition or as an alternative to this, there can also be used derivatives of the aforesaid surfactants, for example such that have functional groups such as —OH, —CH═CH2, —OCO—(CH3)C═CH2 as well as alkoxysilyl groups. In addition, other surfactants known to the person skilled in the art can be used, even if they are less preferred.

As the compounds i) used, there is preferably used a silicone surfactant, since it has been shown in the scope of the present invention that very low contact angles, determined with the “sessile drop” method can be surprisingly obtained in the polyether matrix.

These mixtures are characterized by excellent wettability and outstanding ability to flow onto moist dental and tissue substance. Despite these good hydrophilic properties, the material does not swell on contact with aqueous media, such as water, saliva, blood, disinfectant solution or aqueous plaster slurry. The good initial wettability of the mixtures is important for obtaining a true-to-detail impression with the impression material in the patient's mouth during processing and initial contact with moist oral/dental substance, and is manifested by a low contact angle of smaller than 50°, especially smaller than or equal to 45°, measured with a contact-angle measuring instrument of the Kruss Co. at 20° C. using the “sessile drop” measurement method. In addition, the cured impression material is also characterized at the time of production of a plaster cast (directly or 2 hours after curing) by a contact angle of smaller than 60°, especially smaller than 55°.

In addition, the inventive dental materials can contain one or more active agents j), which, in formulation as a two-component system, can be contained in base component A or in catalyst component B, depending on their chemical functionality. The active agents to be used according to the invention include in particular astringents, such as epinephrine, antibacterial and/or antifungal substances, such as hexitidines (for example, 5-amino-1,3-bis(2-ethylhexyl)-5-methylhexahydropyrimidine), triclosanes (for example, 2,4,4′-trichloro-2-hydroxydiphenyl ether) and chlorhexidine:

    • in which R1, R2 and R3 independently of one another are alkoxy, alkyl, aryl, aralkyl, alkylaryl groups or hydrogen, preferably butoxy, propoxy, ethoxy, methoxy, hexyl, pentyl, butyl, propyl, ethyl or methyl groups, particularly preferably ethoxy, methoxy, ethyl or methyl groups, with the proviso that at least one of the aforesaid groups, preferably two or all three groups, are alkoxy groups.

As plasticizers k) there can be used in particular non-reactive polyethers, polyesters, polyurethanes, phthalates, mono-, di-, tri- or higher esters, especially acetyl tributyl citrate, Mesamoll® (Bayer) and triglycerides, which in formulation as a two-component system are added to component A and/or to component B, depending on their chemical nature.

As the compounds l) permitting optical readability/scanning there can be used all substances known for this purpose to the person skilled in the art, especially metal powder, metal pigments, metallic pigments, zinc oxide, zirconium oxide and titanium dioxide, which in formulation as a two-component system are added to component A and/or to component B, depending on their chemical nature.

In addition, the inventive dental materials can contain, in one of the two or in both components, standard flavors and/or fragrances m) and/or additives n) that are useful for diagnostics, as described in, for example, European Patent 1339373, International Patent PCT/EP00/05418 and German Patent 10061195.

As fluoridating auxiliaries o), there have proved suitable in particular sodium fluoride, potassium fluoride, ammonium fluoride, fluorophosphates and amine fluorides, such as N′-octadecylbimethylenediamine-N,N,N′-bis(2-ethanol) dihydrofluoride (as described in ZM 93, Number 15, pages 32 et seq.), which in formulation as a two-component system can also be added to component A and/or to component B, depending on their chemical nature.

In addition, the inventive dental material, in formulation as a two-component system, can contain as bleaching agent p), in component A and/or component B, one or more various peroxides, which are preferably selected from the group comprising alkali metal and alkaline earth peroxides, hydrogen peroxide and carbamide peroxide.

Examples of suitable desensitization agents q) are potassium salts, such as potassium nitrate, Nelkenol and Eugenol.

As bond promoters r), for example for developing a bond between the impression material and an impression spoon of stainless steel and/or plastic, there are suitable in particular alkoxysilanes, epoxysilanes, aminosilanes and methacrylate silanes.

Examples of suitable dyes s) are dye pigments in the form of Al, Ca, Ba oxides/lacquered dye, which in formulation as a two-component system can also be added to component A and/or to component B, depending on their chemical nature, just as the auxiliary agents described hereinabove, unless otherwise indicated.

Furthermore, dye indicators t), whose color changes as a function of the pH or on the basis of pH changes during mixing of components A and B or upon contact with water, can be added to the inventive dental material in component A and/or component B in formulation as a two-component system.

As stabilizers and/or antioxidants u) there can be used in the inventive two-component dental materials compounds selected in particular from the group comprising polymeric trimethyldihydroquinoline, diphenyl derivatives, phenothiazine, phenyl-α-naphthylamine, 4,4′-methylene-bis-2,6-di-tert-butylphenol, butylhydroxytoluene, butylhydroxyanisole (BHA) and methoxyphenol (hydroxyanisole). Examples of such compounds are the products Irganoz 1010, 1076, 1036, MD 1024, Irgafos 168, 38, Irgacor 252 LD/252FC, 1405, 1930, 153, Tinuvin 328, P, 384, 900, 928, 327, 1130, 400, 292, 144, 123, 622 and Chimassorb 119, which are commercially available from the Ciba-Geigy Co.

Preferably the inventive two-component dental material is stored in suitable primary packages, such as tubes, cans and particularly preferably in cartridges and tubular bags, as described in, for example European Patent 0723807 A2, European Patent A 0541972, International Patent PCT/EP/980193, European Patent A 0492412, European Patent A 0492413 and European Patent 0950908 A1, which are introduced herewith as reference and thus are valid as part of the disclosure, and has been proportioned in a manner tailored to the subsequent use.

Further subject matter of the present invention is mixtures that can be obtained by mixing components A and B of the inventive two-component dental material described hereinabove. Preferably base component A is mixed with catalyst component B in a ratio of 1:1 to 20:1, particularly preferably of 1:1 to 10:1 and quite particularly preferably of 1:1, 2:1, 4:1 or 5:1.

Hereinafter the invention will be explained on the basis of examples that demonstrate the inventive ideas but do not restrict them.

EXAMPLE 1 TO 6 (ACCORDING TO THE INVENTION)

(Production of Various Catalyst Components B with Different Catalyst Salts of Strong Acids and Pyridine to be Used According to the Invention)

Production of Various Catalyst Components B

Various catalyst salts formed from the quantities of strong acids and pyridine indicated in Table 1 were dissolved in 2.9 parts of demineralized water (Ampuwa, pH 5.8). Then the individual salt solutions were mixed for 5 minutes in a vacuum mixing beaker with 36 parts of polypropylene glycol with an average molecular weight of 4000 g/mol, 50 parts of quartz flour with an average particle size of 7 μm and 6 parts of highly disperse, hydrophobed silica with a BET surface of 170 m2/g. Thereafter homogeneous mixing was continued for a further 30 minutes under vacuum.

Medium viscosity materials (ISO 4823), representing the various catalyst components B of the inventive impression material on the basis of alkoxysilyl polyethers, were obtained. The materials were filled into tubular bags (PE/Al/PE laminated film) and stored. They had pH values in the range of pH 1 to pH 3.

Production of a Base Component A

40 parts of a polypropylene glycol, which was functionalized in terminal position with dimethoxymethylsilyl groups via urethane groups and methyl spacers, the functionalized polypropylene glycol having a viscosity of 10,000 mPas at 20° C., was mixed for 5 minutes in a vacuum mixer under dry argon protective gas atmosphere with 50 parts of a dried cristobalite filler surface-modified with trimethylsilyl groups and having an average particle size of 7 μm, 7 parts of a dried, highly disperse, pyrogenically prepared, hydrophobed silica with a BET surface of 170 m2/g, 0.8 parts of vinyltrimethoxysilane and 2 parts of silicone surfactant. Thereafter homogeneous mixing was continued for a further 30 minutes under vacuum.

A medium viscosity material (ISO 4823), representing base component A of the inventive impression material on the basis of alkoxysilyl polyethers, was obtained. The material was filled into tubular bags (PE/Al/PE laminated film) and stored.

Mixing of Catalyst Components B and Base Component A

By means of an electrical dispensing unit (Plug & Press System, Kettenbach GmbH & Co. KG), 1 part of each of the catalyst components B described hereinabove and 5 parts of base component A produced according to the above procedure were mixed homogeneously out of tubular bags via a dynamic mixer.

The setting times of the dental materials based on alkoxysilyl polyethers and produced in this way are listed in Table 1, and further application-related properties for the dental material obtained in Example 2 are listed in Tables 3 and 4.

Examples 1 to 6 show that the inventive compositions surprisingly exhibit curing kinetics that are excellent for condensation-cross-linking systems. Quick-setting impression materials with practical processing times can be obtained. The person skilled in the art is aware that the setting time of the individual examples can be easily adjusted to a desired value by increasing or decreasing the quantity of catalyst salt used.

As follows in particular from Table 4, for the compound obtained in Example 2, the inventive dental materials meet all requirements for functional dental impression material, especially as regards Shore A hardness, recovery after deformation, consistency of the individual components and of the mixture, linear changes of dimensions and contact angle. In particular, there are obtained values that are excellent for the hydrophilicity, which is determined by measurement of contact angle.

COMPARISON EXAMPLE 1 (NOT ACCORDING TO THE INVENTION)

A salt formed from the quantities of pyridine and acetic acid indicated in Table 1 was dissolved in 5.0 parts of demineralized water (Ampuwa, pH 5.8) and processed to a catalyst component B in the same way as in Examples 1 to 6.

One part of the catalyst components B described hereinabove and 5 parts of base component A according to Example 1 were homogeneously mixed out of tubular bags by means of an electrical dispensing unit (Plug & Press System, Kettenbach GmbH & Co. KG) via a dynamic mixer (Kettenbach GmbH & Co. KG).

The setting time of the material based on alkoxysilyl polyether and prepared in this way is listed in Table 1.

As is evident from Table 1, the salt formed from pyridine and a weak acid with a pKs value of 4.76 (acetic acid) and used in Comparison Example 1 has, in contrast to the inventive formulations, an unacceptable setting time of longer than 60 minutes.

EXAMPLES 7 TO 13 (ACCORDING TO THE INVENTION)

(Production of Various Catalyst Components B with Different Catalyst Salts of Strong Acids and Weak Bases to be Used According to the Invention)

Production of Various Catalyst Components B

Various catalyst salts formed from the quantities of strong acids and weak bases indicated in Table 2 were dissolved in 2.9 parts of demineralized water (Ampuwa, pH 5.8). Then the individual salt solutions were mixed for 5 minutes in a vacuum mixing beaker with 36 parts of polypropylene glycol with an average molecular weight of 4000 g/mol, 50 parts of quartz flour with an average particle size of 7 μm and 6 parts of highly disperse, hydrophobed silica with a BET surface of 170 m2/g. Thereafter homogeneous mixing was continued for a further 30 minutes under vacuum.

Medium viscosity materials (ISO 4823), representing the various catalyst components B of the inventive impression material on the basis of alkoxysilyl polyethers, were obtained. The materials were filled into tubular bags (PE/Al/PE laminated film) and stored.

Mixing of Catalyst Components B and Base Component A from Example 1

By means of an electrical dispensing unit (Plug & Press System, Kettenbach GmbH & Co. KG), 1 part of each of the catalyst components B described hereinabove and 5 parts of base component A produced according to Example 1 were mixed homogeneously out of tubular bags via a dynamic mixer (Kettenbach GmbH & Co. KG).

The setting times of the dental materials based on alkoxysilyl polyethers and produced in this way are listed in Table 2.

Examples 7 to 13 show that the inventive compositions surprisingly exhibit curing kinetics that are excellent for condensation-cross-linking systems. Quick-setting impression materials with practical processing times can be obtained. The person skilled in the art is aware that the setting time of the individual examples can be easily adjusted to a desired value by increasing or decreasing the quantity of catalyst salt used.

COMPARISON EXAMPLES 2 AND 3 (NOT ACCORDING TO THE INVENTION)

Two different salts formed from the quantities of p-toluenesulfonic acid and various bases indicated in Table 2 were dissolved in 5.0 parts of demineralized water (Ampuwa, pH 5.8) and processed to a catalyst component B in the same way as in Examples 1 to 6.

One part of each of the catalyst components B described hereinabove and 5 parts of base component A according to Example 1 were homogeneously mixed out of tubular bags by means of an electrical dispensing unit (Plug & Press System, Kettenbach GmbH & Co. KG) via a dynamic mixer (Kettenbach GmbH & Co. KG).

The setting times of the materials based on alkoxysilyl polyether and prepared in this way are listed in Table 2.

As is evident from Table 2, the materials used in the comparison examples and containing salts whose base component has a value outside the PKBH+ range of −1 to 7 specified according to the invention do not cure.

COMPARISON EXAMPLES 4 (NOT ACCORDING TO THE INVENTION)

(Acid-Catalyzed Condensation Cross-Linked Dental Material on the Basis of Alkoxysilyl Polyethers According to Examples 3 and 5 of European Patent 1226808 A2)

A prior art acid-catalyzed dental material based on alkoxysilyl polyethers and composed of an acid catalyst component B and a base component A is prepared and mixed according to Examples 3 and 5 of European Patent 1226808 A2.

The processing time, setting time and setting time after a thermal stress test of one week at 60° C. of the composition prepared according to Comparison Example 4 are listed in Table 3, by comparison with the dental material based on alkoxysilyl polyethers and obtained according to the invention in Example 2.

Compared with the inventive dental material based on alkoxysilyl polyethers and obtained in Example 2, the acid catalyst system from European Patent 1226808 A2 (Examples 3 and 5) no longer exhibits curing after storage in the thermal stress test (one week at 60° C.) This shows that the catalyst component from Example 3 of European Patent 1226088 A2 is unstable. This leads to lengthening of the setting time. However, a setting time that remains constant independently of storage time is one of the most important requirements of a dental impression material.

TABLE 1 Composition and setting time of the compounds according to Examples 1 to 6 and Comparison Example 1 Acid proportion Base proportion pKs value Inventive Examples/ [%] [%] of acid Comparison Examples Strong acids Weak base Content [mmol/g] Content [mmol/g] (H2O) Setting time Example 1 Benzenesulfonic acid Pyridine 1.46 0.73  0.7 4) 6′30″ (6.32) (12.64) Example 2 p-Toluenesulfonic acid Pyridine 1.58 0.73  0.7 2) 7′30″ (5.81) (12.64) Example 3 Trifluoromethanesulfonic Pyridine 1.38 0.73 −10 3) 8′00″ acid (6.66) (12.64) Example 4 4-Sulfophthalic acid Pyridine 2.27 0.73  <0.7 11′00″  (4.06) (12.64) Example 5 Trichloroacetic acid Pyridine 1.5 0.73  0.7 4) 12′00″  (6.12) (12.64) Example 6 Trifluoroacetic acid Pyridine 1.05 0.73  −0.25 2) 13′00″  (8.77) (12.64) Comparison Example 1 Acetic acid Pyridine 1.29 0.73  4.76 4)  >60′00″    (4.06) (12.64)
2) Source: http://www.cem.msu.edu/˜reusch/VirtualText/suppmnt2.htm

3) Source: http://www.tgs-chemie.de/pks-werte.htm

4) Source: http://www.zirchrom.com/organic.htm, “Dissociation constants of organic acids and bases”

TABLE 2 Composition and setting time of the compounds according to Examples 7 to 13 and Comparison Examples 2 and 3 Acid Base proportion proportion pKS [%] [%] value of Inventive Examples/ Content Content acid Setting Comparison Examples Strong acids Weak base [mmol/g] [mmol/g] (H2O) time Example 7 p-Toluenesulfonic acid Pyrrole 0.19 0.49 0.0 2)  <30 s (14.91) (5.81) Example 8 p-Toluenesulfonic acid 2,4-Dimethylpyrrole 0.88 1.58 2.55 3) <30 s (10.51) (5.81) Example 9 p-Toluenesulfonic acid 2,5-Dimethylpyrrole 0.88 1.58 −0.71 3)  <30 s (10.51) (5.81) Example 10 p-Toluenesulfonic acid N,N-Dimethylaniline 1.11 1.58 5.15 4) <1′00″  (8.25) (5.81) Example 11 Trifluoromethanesulfonic N,N-2,4,6-Pentamethylaniline 0.47 0.43 5.15 5) 4′00″ acid (6.13) (6.66) Example 12 p-Toluenesulfonic acid N,N-2,4,6-Pentamethylaniline 0.47 1.58 5.15 5) 6′00″ (6.13) (5.81) Example 13 p-Toluenesulfonic acid Pyridine 0.73 1.58 5.25 4) 8′30″ (12.64) (5.81) Comparison Example 2 p-Toluenesulfonic acid 1,4- 0.32 0.49 8.8 2)  no Diazabicyclo[2.2.2]octene (8.91) (5.81) reaction Comparison Example 3 p-Toluenesulfonic acid Triethanolamine 0.43 0.49 7.77 4) no (6.70) (5.81) reaction
2) Source: http://www.cem.msu.edu/˜reusch/VirtualText/suppmnt2.htm

3) Source: Y. Chiang, E. B. Whipple, J. Am. Chem. Soc., 1963, Vol. 85, 2763

4) Source: http://www.zirchrom.com/organic.htm, “Dissociation constants of organic acids and bases”
5) In 50% alcohol. Source: W. C. Davies, H. W. Addis, J. Chem. Soc., 1937, 1622

TABLE 3 Processing times, setting times and stabilities of impression materials on the basis of alkoxysilyl polyethers by comparison with Examples 3 and 5 of European Patent 1226808 A2 Stability: Setting time Impression after one week material: Processing time 1) Setting time 4) at 60° C. 3) Example 2 3.00 minutes 7.50 minutes  7.75 minutes Comparison 0.50 minutes 5.00 minutes >15.00 minutes Example 4 (Examples 3 and 5 of European Patent 1226808 A2)
1) According to ISO 4823

2) The setting time was determined by recovery after deformation in accordance with ISO 4823 (1992 Edition)

3) Storage in sealed tubular bags of PE/A1/PE laminated film, see under 2) for measurement

TABLE 4 Application-related properties of the compositions according to Example 2 Example 2 Catalyst salt of p-toluenesulfonic acid with pyridine Consistency 1) 30 Catalyst component B Consistency 1) 33 Base component A Consistency of the mixture 2) 36 Linear dimensional change 3) −0.60% Shore A hardness immediately after end of 30 setting 4) Shore A hardness immediately after 15 hours of 60 storage 4) Contact angle 5) 30°/40° Recovery after deformation 6) 98.05%
1) On the basis of ISO 4823, consistency of the mixture, loading weight 500 g, loading time 15 seconds

2) According to ISO 4823, consistency of the mixture, loading weight 1500 g, loading time 5 seconds

3) According to ISO 4823

4) According to DIN 53505 with Zwick Co. digital Shore hardness tester

5) Measured according to the sessile drop method, G40 contact-angle measuring system of the Krüss Co., initial contact angle (age of specimen tested: application of the drop 45 seconds after the start of mixing), measurement time: 30 seconds after application of the drop. Use of demineralized water.

6) According to ISO 4823

Claims

1. A condensation-cross-linking dental material, especially dental impression material, containing:

a) at least one alkoxysilyl-functional polyether and
b) at least one catalyst,
wherein the at least one catalyst b) is a salt formed from a weak organic base whose PKBH+ value measured in water is between −1 and 7 and at least one strong acid whose pKs value measured in water is lower than 2.

2. A condensation-cross-linking two-component dental material, especially dental impression material, with a component A containing:

a) at least one alkoxysilyl-functional polyether and a component B containing
b) at least one catalyst and
c) water,
wherein the at least one catalyst b) is a salt formed from a weak organic base whose pKBH+ value measured in water is between −1 and 7 and at least one strong acid whose pKs value measured in water is lower than 2.

3. A condensation-cross-linking dental material according to claim 1, wherein the at least one catalyst b) is a salt formed from a weak organic base whose pKBH+ value measured in water is between −1 and 7 and at least one strong acid whose pKs value measured in water is lower than 2, the acid having a structure that permits mesomeric stabilization of the negative charge after deprotonation of the acid.

4. A condensation-cross-linking dental material according to claim 1, further comprising at least one reinforcing filler d1) with a BET surface of at least 50 m2/g and/or at least one non-reinforcing filler d2) with a BET surface of smaller than 50 m2/g.

5. A dental material according to claim 1, wherein the at least one catalyst salt used is formed from at least one base whose PKBH+ value measured in water is between 1 and 7, particularly preferably between 2 and 6 and quite particularly preferably between 3 and 6 and/or at least one acid whose pKs value measured in water is smaller than 1 and particularly preferably smaller than or equal to 0.7.

6. A dental material according to claim 1, wherein the at least one catalyst is a salt formed from an acid chosen from the group comprising p-toluenesulfonic acid, fluorosulfonic acid, trifluoromethanesulfonic acid, fluorosulfuric acid, 4-sulfophthalic acid, trichloroacetic acid, trifluoroacetic acid, benzenesulfonic acid and combinations thereof and/or from a base selected from the group comprising pyrrole derivatives, dimethylaniline, pyridine, 2,4,6-N,N-pentamethylaniline, N,N-dimethylaniline, phenetedine, acridine, phenanthridine, quinoline, isoquinoline, 2-amino-4,6-dimethylpyrazine, 4,6-dimethylpyridinamine, 3-methylpyridine (3-picoline), 4-phenylpyridine, 4-vinylpyridine, pyridazine, 2-ethylpyridine, 2-butylpyridine, 1,7-phenanthroline, 2-aminopyrimidine, 2-isopropylpyridine, 2-vinylpyridine, 2-N,N-dimethylaminopyridine, quinazoline, 4-chloropyridine, phenazine, 4-acetylpyridine, methyl nicotinate, 3-benzoylpyridine, 2,2′-bipyridine, 2-phenylpyridine, 2-tert-butylpyridine, pyrimidine, 3-iodopyridine, 3-fluoropyridine, 3-chloropyridine, 3-bromopyridine, pyrazine, 7,8-benzoquinoline, 2-chloropyridine, 4-cyanopyridine and combinations thereof.

7. A dental material according to claim 1, further comprising, relative to the total mixture, 0.0005 to 0.5 mmol/g, particularly preferably 0.0005 to 0.25 mmol/g and quite particularly preferably 0.0005 to 0.05 mmol/g of catalyst salt.

8. A dental material according to claim 1, wherein the at least one catalyst salt in the polyether matrix, preferably a polyether matrix comprising as structural unit polytetrahydrofuran, polyethylene glycol and particularly preferably polypropylene glycol as well as mixtures and copolymers thereof, has sufficiently high solubility that, when used in a quantity of 0.0005 to 0.5 mmol/g relative to the total mixture, it achieves curing of the dental material, determined by recovery after deformation according to ISO 4823 (1992 edition), in less than or equal to 30 minutes, particularly preferably less than or equal to 15 minutes for a duplicating compound and in less than or equal to 15 minutes, particularly preferably less than or equal to 10 minutes, quite particularly preferably less than or equal to 7 minutes and most preferably less than or equal to 6 minutes for a dental impression compound.

9. A dental material according to claim 1, wherein, besides the one or more salts according to claim 1, the dental material contains no further catalyst, especially no metalloorganic compounds, heavy metal carboxylate salts, tertiary amines and free acids.

10. A dental material according to claim 1, wherein the at least one alkoxysilyl-functional polyether a) contains, as a third structural unit, alkylene spacers, which are disposed on each of the terminal alkoxysilyl groups and which are particularly preferably C1 to C6 alkyl groups, quite particularly preferably C1 to C3 alkyl groups and most particularly preferably ethylene groups (C2) and/or methylene groups (C1) and, as a fourth structural unit, 0 to 8 mmol/g, particularly preferably 0 to 4 mmol/g, quite particularly preferably 0.02 to 2 mmol/g and most preferably 0.1 to 0.4 mmol/g of urethane groups and/or 0 to 8 mmol/g, particularly preferably 0 to 2 mmol/g, quite particularly preferably 0.02 to 2 mmol/g and most preferably 0.1 to 0.4 mmol/g of urea groups, wherein the alkoxysilyl polyethers that are most preferred are those that contain no urethane or urea groups within the polyether chain and that have at each chain end at most one or not more than one urethane and/or urea group and at most one or not more than one methylene spacer group, the individual structural units of the at least one polyether a) preferably being arranged according to

in which R1, R2 and R3 independently of one another are alkoxy, alkyl, aryl, aralkyl, alkylaryl groups or hydrogen, preferably butoxy, propoxy, ethoxy, methoxy, hexyl, pentyl, butyl, propyl, ethyl or methyl groups, particularly preferably ethoxy, methoxy, ethyl or methyl groups, with the proviso that at least one of the aforesaid groups, preferably two or all three groups, are alkoxy groups, as well as x=1 to 6, preferably x2 to 4 and quite particularly preferably x=2, n=1 to 6, preferably n=1 to 3 and quite particularly preferably n=1, as well as m=0 or 1, particularly preferably m=1,
and/or
in which R1, R2 and R3 independently of one another are alkoxy, alkyl, aryl, aralkyl, alkylaryl groups or hydrogen, preferably butoxy, propoxy, ethoxy, methoxy, hexyl, pentyl, butyl, propyl, ethyl or methyl groups, particularly preferably ethoxy, methoxy, ethyl or methyl groups, with the proviso that at least one of the aforesaid groups, preferably two or all three groups, are alkoxy groups, as well as x=1 to 6, preferably x=2 to 4 and quite particularly preferably x=2, n=1 to 6, preferably n=1 to 3 and quite particularly preferably n=1, as well as l=0 or 1, particularly preferably l=1.

11. A dental material according to claim 10, wherein n is equal to 1.

12. A dental material according to claim 1, wherein the at least one polyether a) contains a structural unit selected from the group comprising polytetrahydrofuran, polyethylene glycol, polypropylene glycol, copolymers thereof and mixtures thereof.

13. A dental material according to claim 1, further comprising at least one paste-forming agent h), which is preferably selected from the group comprising polyethers, polyvinylpyrrolidones, polyurethanes, polyesters, waxes, vaselines, paraffin oils, silicone oils, polyhydric alcohols, propylene glycols, polypropylene glycols, ethylene glycols, polyethylene glycols, copolymers of N-vinylpyrrolidone and vinyl acetate, carboxymethyl-, methyl-, hydroxyethyl-, hydroxypropylcellulose, polysaccharides and poly(meth)acrylic acids.

14. A dental material according to claim 1, further comprising at least one water scavenger g), which preferably is vinyltrimethoxysilane, N-trimethoxysilylmethyl-O-methyl carbamate and/or a compound of the following formula:

in which n=1 to 6, preferably n=1 or 3, particularly preferably n=1, d=0 or 1, and R10=a linear or branched C1 to C30 alkyl group, in which some of the hydrogen atoms may be substituted by halogen atoms, OH—, NH2—, NO2— or even other C1 to C6 alkyl groups.

15. A mixture that can be obtained by mixing components A and B of the two-component dental material according to claim 2, wherein the base component A is mixed with the catalyst component B in a ratio of 1:1 to 20:1, particularly preferably of 1:1 to 10:1 and quite particularly preferably of 1:1, 2:1, 4:1 or 5:1.

16. The use of a dental material according to claim 1 in dental medicine or dentistry.

Patent History
Publication number: 20050250871
Type: Application
Filed: Feb 14, 2005
Publication Date: Nov 10, 2005
Inventors: Alexander Bublewitz (Herborn), Jens-Peter Reber (Meinerzhagen)
Application Number: 11/057,794
Classifications
Current U.S. Class: 523/109.000