Monomer mixture for producing a dental material

Abstract

The invention relates to a monomer mixture for producing a dental material, comprising: a. at least one base monomer M1 of the following empirical formula 1: KnUm(O-S-PG)o (formula 1), b. at least one base monomer of the following formula 4: PG'–S'–A'–S'–PG' (formula 4), and a monomer mixture for producing a dental material, comprising at least one or more base monomers M1 of the empirical formula 1, the use of the monomer mixtures, polymerizable dental materials containing such monomer mixtures, polymerizable dental materials for use in a therapeutic method and cured dental materials.

Description

[0001] Monomer mixture for the production of a dental material

[0002] The invention relates to a monomer mixture for producing a dental material, a use of the monomer mixture, a polymerizable dental material containing such a monomer mixture, a polymerizable dental material containing such a monomer mixture for use in a therapeutic method, and a cured dental material.

[0003] Radically polymerizable dental materials primarily contain (meth)acrylate monomers. Dimethacrylate systems are commonly used for restorative and prosthetic dental materials, such as dental fillings and dentures, due to their properties such as rapid radical polymerization, good mechanical properties, and aesthetic appearance. Commonly used base monomers are linear, aliphatic or aromatic group-containing structures with terminal methacrylate functionalities and a high molecular weight, such as 2,2-bis-[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane (BisGMA) and 7,7,9-trimethyl-4,13-dioxo-3,14-dioxa-5,12-diazahexadecane-1,16-diyl-bis(2-methylacrylate) (UDMA).

[0004] For some time now, efforts have been made to largely eliminate the use of BisGMA and replace it, at least partially, with other compounds. The focus is primarily on urethane monomers and oligomers. UDMA is the most widely used commercially as at least a partial replacement for BisGMA in the field of dental materials.

[0005] Base monomers such as BisGMA and UDMA, although widely used in commercial radically polymerizable dental materials, have several disadvantages. They are generally highly viscous to solid substances. Therefore, mixtures with monomers with a significantly lower viscosity, such as triethylene glycol dimethacrylate (TEGDMA), are used. TEGDMA is a very flexible, low-molecular-weight monomer with a low viscosity (of 0.01 Pa s) and exhibits high mobility during polymerization, which favors polymerization conversion.

[0006] However, these monomer mixtures and the dental materials obtained from them exhibit several problematic properties that can impair their clinical treatment success. For example, monomer mixtures of these dimethacrylate monomers exhibit a relatively low polymerization conversion, significant polymerization shrinkage, poor toughness, and undesirable water absorption. The known systems can often only achieve a comparatively low conversion of the double bonds, which not only contributes to poor mechanical properties and wear resistance, but is also detrimental to the toxicology and biocompatibility of the polymerized dental materials.Furthermore, the volumetric shrinkage of currently used dimethacrylate monomers and the shrinkage stresses of a dental filling can lead to failure of the bond between tooth and filling, resulting in microleakage and subsequent secondary caries, which in turn can significantly reduce the longevity of the restoration. Attempts to increase double bond conversion to reduce unreacted monomers unfortunately lead to an increase in polymerization shrinkage and shrinkage stress.

[0007] Low-molecular-weight monomers with oligo[ethyleneoxy] groups, such as TEGDMA, which exhibit a certain degree of water solubility and thus bioavailability, are now being critically evaluated due to their toxicological properties and their sensitivity to biodegradation processes. Monomers with the structural element bis-2,2-[p-oxyphenyl]propane, i.e., monomers based on bisphenol A, are also being critically evaluated, as dental materials containing monomer mixtures with these structural elements have been found to release detectable amounts of bisphenol A, which is considered to have critical toxicological properties.

[0008] There are various approaches to increasing conversion or reducing volume shrinkage. In dental composites for dental fillings, which contain filler in an organic resin matrix, attempts are made to reduce volume shrinkage by increasing the filler content. However, if the filler content is too high, it is difficult to mix the fillers with the organic resin. Furthermore, the filler content for dental composites is limited. Therefore, the possibility of reducing polymerization shrinkage by increasing the filler content is fundamentally limited.

[0009] New monomers continue to be developed to increase conversion and reduce polymerization shrinkage, such as high-molecular-weight urethane methacrylate monomers. For a given functionality of the monomers, increasing the molecular weight is generally associated with a deterioration in the mechanical properties of the cured dental materials. Furthermore, the increased viscosity of such monomers requires the use of larger amounts of low-viscosity monomers for use in dental composites, which has an adverse effect on shrinkage.

[0010] EP 2436365 B1 describes low-shrinkage dental composites containing monomer mixtures containing the monomers (b1) and (b2) in a ratio of 1:20-5:1. The example compositions each contain 4.8-76.6 wt.% bis((meth)acryloyloxymethyl)tricyclo[5.2.1.0 2 ' 6]decane (bl), 90.9-19.1 wt.% UDMA (b2), and 4.3 wt.% TEGDMA (b2). These composites exhibit a polymerization shrinkage of approximately 1.50%, regardless of the ratio (bl) to (b2). If, as in Comparative Example 11, the filler content is reduced and the TEGDMA content is increased, the polymerization shrinkage increases.

[0011] Vaidyanathan et al., Visible light cure characteristics of a cycloaliphatic polyester dimethacrylate alternative oligomer to bisGMA; Acta Biomater Odontol Scand. 2015; 1:59-65, disclose the use of PEM-665 as a BPA-free alternative to BisGMA in combination with 30 or 50 wt% TEGDMA. The polymerization conversions of these mixtures were investigated, with the combinations of PEM with TEGDMA exhibiting a higher percentage polymerization conversion than the combinations of BisGMA with TEGDMA.

[0012] US Pat. No. 4,554,336 describes orthodontic adhesives based on trifunctional polyetherurethane (alk)acrylates with a nonlinear structure. However, the urethane acrylates with a nonlinear structure described in US Pat. No. 4,554,336 lead, among other things, to dental composites with a reduced elastic modulus.

[0013] There is therefore a need for monomers or monomer mixtures that can enable a reduced toxicity potential and reduced volume shrinkage while simultaneously maintaining good mechanical properties of the dental material produced therefrom, in particular a dental restoration and filling material, and that are easily available. The present invention is therefore based on the object of providing a monomer mixture that overcomes the above-mentioned disadvantages of the prior art and that, in particular, enables the production of dental materials, especially dental composites, with improved volume shrinkage, improved flexural strength, and a good modulus of elasticity.

[0014] The invention solves this problem by a monomer mixture for producing a dental material, comprising: a. at least one base monomer M1 of the following empirical formula 1:

[0015] KnUm(OS-PG)o (Formula 1), where

[0016] PG = a polymerizable group selected from -OOC- CH=CH2 and -OOC-C(CH3)=CH2;

[0017] S = a spacer group selected from unbranched and branched alkylene with Cl-ClO carbon atoms, which may additionally contain oxygen and / or -OOC- in the carbon chain, preferably ethylene;

[0018] 0 = oxygen;

[0019] U = a group represented by the following formula 2:

[0020] -CO-NH-A-NH-CO- (Formula 2), where A = a group selected from a divalent aromatic or aliphatic C6-C20 hydrocarbon group, preferably a divalent aliphatic C6-C13 hydrocarbon group, more preferably a divalent saturated, cyclic C6-C13 hydrocarbon group;

[0021] K = a group represented by the following formula 3:

[0022] T(O) S [((OR) r )O]t (Formula 3), where

[0023] T = a trivalent hydrocarbon group with C3-C7 carbon atoms,

[0024] 0 = oxygen,

[0025] R = each independently selected from an ethylene group, a 1,2-propylene group, a 1,3-propylene group and a mixture thereof, preferably a 1,2-propylene group, r = each independently 1-12, preferably 1-9, even more preferably 1-6, s = 0 or 1, preferably 0, t = 2 or 3, preferably 3, where the condition must be met that s+t = 3; n = 1-9, preferably 1-7, even more preferably 1-5; where the conditions must be met that m = 2n+1 and o = n+2; b. at least one base monomer M2 of the following formula 4:

[0026] PG'-S'-A'-S'-PG' (Formula 4), where

[0027] PG' = a polymerizable group selected from 00C-CH=CH2 and -OOC-C(CH3)=CH2;

[0028] S' = a spacer group selected from unbranched and branched alkylene with Cl-ClO carbon atoms, which may additionally contain oxygen and / or - 00C- in the carbon chain, is preferably methylene, or S' is omitted;

[0029] A' = an aliphatic polycyclic group, preferably an aliphatic tricyclic hydrocarbon group in which one or more hydrogen atoms can each independently be replaced by Cl-C4-alkyl radicals, Cl-C4-alkoxy radicals, fluorine atoms, chlorine atoms or trifluoromethyl groups, more preferably tricyclodecanylene, even more preferably tricyclo [5.2.1.0 2 ' 6 ]decanylene.

[0030] Preferred embodiments are found in the subclaims.

[0031] First, some terms used in the context of the invention will be explained. According to the invention, polymerizable dental materials are understood to mean materials for (bio)medical use, particularly on hard tooth substance, such as enamel and dentin, or on bone tissue, such as the jawbone.

[0032] The polymerizable dental material is typically a resin-based material, which is a mixture of various curable components. In the context of this invention, a resin essentially consists of the monomer mixture and other components soluble in the monomers, such as initiators, stabilizers, etc.

[0033] In the context of the present invention, a monomer mixture is a mixture comprising base monomers M1 and M2, as well as optionally base monomers M3 and / or other monomers (SM) of the polymerizable dental material. Other components of the polymerizable dental material, such as initiator, filler, conventional dental additive, etc., are not components of the monomer mixture.

[0034] In the context of the present invention, base monomer M1 is a monomer when n = 1, and oligomers when n = 2 to 9. Monomers and oligomers with n = 1 to 9 are also referred to as base monomers M1.

[0035] In the context of the invention, T in formula 3 is a trivalent hydrocarbon group with C3-C7 carbon atoms. In the context of the invention, trivalent means that three bonds originate from the group T, with these bonds preferably originating from three different carbon atoms. Preferably, T is a carbon radical derived from glycerol, 2-

[0036] Ethyl 2-(hydroxymethyl)propane-1,3-diol, hexanetriol (1,2,6-isomer, 1,3,5-isomer, 1,2,3-isomer, 2,3,5-isomer and mixtures thereof), butanetriol, 2-(hydroxymethyl)propane-1,3-diol, 2-methylpropane-1,2,3-triol, pentanetriol, 2-(hydroxymethyl)butane-1,4-diol, 2-(hydroxymethyl)butane-1,3-diol, 3-methylpentane-1,3,5-triol, 2-(hydroxymethyl)hexane-1,6-diol and 3-(hydroxymethyl)hexane-1,6-diol. Furthermore, the C3-C7 carbon radical can also be derived from any other trifunctional alcohol known in the art. More preferably, T is a trivalent hydrocarbon group with C3 carbon atoms. In a preferred embodiment, T is represented by the following formula 5: (Formula 5), ​​where the bonding sites to the oxygen atoms of formula 3 are represented by the indicated bond (ie the broken lines).

[0037] In the context of the invention, A in formula 2 is a group selected from a divalent aromatic or aliphatic C6-C20 hydrocarbon group. In the context of the invention, divalent means that two bonds originate from the group A, with these bonds preferably originating from two different carbon atoms. Preferably, A is a divalent aliphatic C6-C13 hydrocarbon group, more preferably a divalent saturated, cyclic C6-C13 hydrocarbon group. Preferably, A is a divalent cyclic hydrocarbon group having 10 carbon atoms. In a preferred embodiment, A is represented by the following formula 6: where the two indicated bonds (ie the broken lines) each represent the bonding sites to the nitrogen atoms of formula 2.

[0038] Preferably, the monomer mixture contains several base monomers Ml, more preferably at least two base monomers Ml, even more preferably more than two base monomers Ml, further preferably more than three base monomers Ml, even more preferably more than four base monomers Ml, even more preferably more than five base monomers Ml, etc. In such a case that the monomer mixture contains several base monomers Ml, it is preferably a mixture which, in addition to base monomers, also comprises base oligomers. According to the invention, such a mixture is also referred to as a mixture of base monomers Ml.

[0039] It is preferred that, in addition to the base monomer Ml with n = 1 (i.e., a monomer), at least one base monomer Ml with n greater than 1 (i.e., an oligomer) is also present. The mass fraction of the base monomer(s) Ml with n greater than 1, which can be determined by fractionation by means of gel permeation chromatography using a refractive index detector (measurement with visible light), is preferably 5-70 wt.%, more preferably 10-60 wt.%, even more preferably 15-50 wt.%, based on the total mass of all base monomers Ml of a monomer / oligomer series of n = 1-9. The distribution of the base monomers Ml with respect to n can vary within wide ranges. It may be that the basic monomers Ml in which n = 2-5 or n = 2-4 have the highest mass fraction, based on the total mass fraction of the basic monomers Ml.However, it may also be the case that the base monomer(s) Ml with n = 1 has the highest mass fraction compared to each individual base monomer Ml with n = 2-9 contained in the monomer mixture.

[0040] Below, some structures of the base monomer Ml for different n values ​​are explained. For the case where n = 1, taking into account the conditions that m = 2n+l and o = n+2, the molecular formula K1U3(OS-PG)3 for the base monomer Ml results. Due to the combination of the trivalent group K with the divalent group U and the monovalent group -OS-PG, the structure shown in the following formula 7 for the base monomer Ml results for n = 1: (Formula 7).

[0041] If n = 2, the molecular formula for the base monomer Ml is K2U5(OS-PG)4. In this case, the base monomer Ml can be represented by the structure shown in formula 8: (Formula 8). If n = 3, the molecular formula for the base monomer is K3U7(OS-PG)5. In this case, the base monomer Ml can be represented by the structure shown in Formula 9: (Formula 9).

[0042] For the case where n = 4, the molecular formula for the base monomer is K4U9(OS-PG)e. For n = 4, the base monomer Ml can be represented by two different structures, which are shown below in formulas 10 and 11: .

[0043] For the case where n = 5, the molecular formula for the base monomer is K5U11(OS-PG)7. For n = 5, the base monomer Ml can also be represented by two different structures, which are shown below in formulas 12 and 13:

[0044] For the cases where n = 6-9, there are correspondingly more structures for each additional n.

[0045] Specifically, within group K, three carbon atoms of group T bind to corresponding oxygen atoms T (O)s[((OR) r )0]t or T (0)s[((OR) r )0]t. The group K can be linked via the labeled oxygen atoms T (O) s [((OR) r )0]tresp.

[0046] T (0)s[((0R) r )O]t be bonded to carbamoyl carbon atoms -CO-NH- of group U. The carbamoyl carbon atoms -NH-CO- of group U can be bonded either to an oxygen atom of group -OS-PG or to an oxygen atom of group K

[0047] (T (0)s[((0R) r )O]t or T (O)s[((0R) r )0]t) or to two oxygen atoms of different groups K. The oxygen atom of the group -OS-PG always bonds to a carbamoyl carbon atom -NH-CO- of the group U.

[0048] The base monomers Ml with n > 1 are present as base monomers with n = 2-9, preferably with n = 2-7, more preferably with n = 2-5. In one embodiment, all base monomers Ml of a monomer / oligomer series with n = 1-9, preferably with n = 1-7, more preferably with n = 1-5, can be present alongside one another. This means that if at least one compound is present for each n from 1-9, then at least 9 compounds (i.e., one monomer for n = 1 and eight oligomers for n = 2, 3, 4, etc.) would be present in the monomer mixture (or monomer / oligomer mixture). For n = 1-7, at least 7 compounds (ie, one monomer and six oligomers) and for n = 1-5, at least 5 compounds (ie, one monomer and four oligomers) would be present in the monomer mixture.

[0049] Within the scope of the invention, r is in each case independently 1-12, preferably 1-9, even more preferably 1-6. Since t can vary in the base monomer Ml, ie t can be 2 or 3, the number of radicals r present also varies accordingly. This means that within the scope of the invention, r can correspond either to the radicals rl and r2 or to the radicals rl, r2 and r3. Within the scope of the invention, the radicals rl-r2 and rl-r3 in a base monomer Ml can each be the same or they can differ from one another.

[0050] This means that the groups K can be distributed according to molecular weight, since the groups -OR- with different stoichiometric indices rl, r2, r3 can be present next to each other.

[0051] The sum of the coefficients rl, r2, r3 is preferably greater than 3. In a preferred embodiment, rl + r2 + r3 = 4- 20.

[0052] The base monomer M2 can be selected from bis(methacryloyloxymethyl)tricyclo[5.2.1.0 / 2,6]decane, bis(acryloyloxymethyl)tricyclo[5.2.1.0 / 2,6]decane, and mixtures thereof. More preferably, the base monomer M2 is bis(acryloyloxymethyl)tricyclo[5.2.1.0 / 2,6]decane. The base monomer M2 can be a commercially available monomer, such as tricyclo[5.2.1.0 / 2,6]decane dimethanol diacrylate from Polyscience. However, it can also be monomers that can be obtained by esterification reaction, e.g., according to the preparation examples in EP0235836B1 or US4131729 / DE2816823. Technically available base monomers M2 based on tricyclo[5.2.1.0 / 2,6]decane dimethanol di(meth)acrylate generally contain isomer mixtures in which the exocyclic methylene groups are bonded to different framework C atoms depending on the isomer.

[0053] The monomer mixture may comprise a base monomer M3 which differs from the base monomers M1 of formula 1 and M2 of formula 2.

[0054] The base monomer M3 is preferably selected from urethane-based monomers.

[0055] Suitable base monomers M3 can be selected from difunctional urethane (meth)acrylates, polyfunctional urethane (meth)acrylates and mixtures thereof.

[0056] The base monomer M3 is preferably urethane di(meth)acrylate. Urethane di(meth)acrylates are preferably selected from linear or branched alkylene bis(urethane (meth)acrylates) and urethane di(meth)acrylate-functionalized polyethers.

[0057] Preferred are difunctional urethane (meth)acrylates selected from difunctional urethane (meth)acrylates with a bivalent alkylene group and those with a bivalent cyclic aliphatic hydrocarbon group. Difunctional urethane (meth)acrylates with a bivalent alkylene group are preferably selected from linear or branched urethane di(meth)acrylates functionalized with a bivalent alkylene group, such as bis(methacryloxy-2-ethoxycarbonylamino)alkylene.

[0058] The difunctional urethane (meth)acrylates can thus be compounds of the following formula 14, which have a group B selected from a bivalent linear or branched alkylene group and a bivalent cyclic aliphatic hydrocarbon group; which have a group Z selected from linear and branched C2-C8 hydrocarbon radicals in which one or more carbon atoms can optionally be replaced by oxygen, nitrogen or sulfur; and which have groups X, each of which can independently be methyl or H. An example is bis(methacryloxy-2-ethoxycarbonylamino)alkylene. The bivalent alkylene preferably comprises 2,2,4-trimethylhexamethylene and / or 2,4,4-trimethylhexamethylene. Preference is given to 1,6-bis(methacryloxy-2-ethoxycarbonylamino)-2,4,4-trimethylhexane. Examples include UDMA and HEMA-TDMI. (Formula 14)

[0059] The base monomer M3 can also be urethane di(meth)acrylate-functionalized polyethers with alkylene group(s), such as bis(methacryloxy-2-ethoxycarbonylamino)-substituted polyalkylene ethers. In these cases, group B from formula 14 is a polyether group. Preference is given to compounds containing bis(methacryloxy-2-ethoxycarbonylamino) which comprise linear or branched alkylene groups with C3 to C20, preferably C3 to C9, or bivalent cyclic aliphatic groups with C3 to C20, preferably C3 to C9. It can also be a methyl-substituted alkylene or a methyl-substituted cyclohexyl group.

[0060] Furthermore, the base monomer M3 can also be HP-UDMA, a reaction product of 3-hydroxypropyl methacrylate and trimethylhexamethylene diisocyanate, or HP-UDA, a reaction product of 3-hydroxypropyl acrylate and trimethylhexamethylene diisocyanate.

[0061] Urethane (meth)acrylates with a bivalent cyclic aliphatic hydrocarbon group are accessible by reacting 2 mol of 2-hydroxyethyl methacrylate (HEMA) or 2 mol of 2-hydroxyethyl acrylate (HEA) with 1 mol of cyclic aliphatic diisocyanate. Suitable diisocyanates are isophorone diisocyanate (1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane) or HI2-MDI (1-isocyanato-4-[(4-isocyanatocyclohexyl)methyl]cyclohexane) as well as other cyclic diisocyanates. Examples of these are UDA-IPDI, the reaction product of two molecules of 2-hydroxyethyl acrylate (HEA) and one molecule of isophorone diisocyanate (IPDI), and UDMA-IPDI, the adduct of two molecules of 2-hydroxyethyl methacrylate (HEMA) and one molecule of isophorone diisocyanate.

[0062] Suitable base monomers M3 are available, for example, under the following trade or brand names: Ebecryl 230 (aliphatic urethane diacrylate), CN9200 (aliphatic urethane diacrylate), Ebecryl 210 (aromatic urethane diacrylate oligomers), Ebecryl 270 (aliphatic urethane diacrylate oligomer), Photomer 6210 (aliphatic urethane diacrylate), Photomer 6891 (aliphatic urethane diacrylate), UDMA, Genomer 4256 (aliphatic urethane dimethacrylate), Genomer 4267 (aliphatic urethane diacrylate), Genomer 4259 (aliphatic urethane diacrylate), RCX 18-059 (aliphatic urethane diacrylate), GN 1963CG (aliphatic urethane methacrylate), CN 1993CG (aliphatic urethane methacrylate), PRO 21252 (aliphatic urethane acrylate), H1391 (hydroxypropyl urethane dimethacrylate), X851-1066 (urethane dimethacrylate), X726-000 (PEG 400 extended urethane dimethacrylate), and, Urethane methacrylate 14-774 (aliphatic urethane dimethacrylate), Genomer 4277 (aliphatic urethane dimethacrylate).

[0063] The base monomer M3 is preferably selected from 7,7,9- (or 7,9,9-)trimethyl-4,13-dioxo-3,14-dioxa-5,12-diazahexadecane-1,16-diyl-bis (2-methylacrylate) (UDMA), 7,7,9- (or 7,9,9-)trimethyl-4,13-dioxo-3,14-dioxa-5,12-diaza-hexadecane-1,16-diol diacrylate (UDA), the reaction product of 2 molecules of 2-hydroxyethyl acrylate (HEA) and one molecule of isophorone diisocyanate (IPDI) (UDA-IPDI) and mixtures thereof.

[0064] In a preferred embodiment, the base monomer M3 is selected from UDMA, UDA, UDA-IPDI and mixtures thereof.

[0065] Furthermore, the monomer mixture may contain other monomers. Other monofunctional monomers are preferably selected from MMA (methyl methacrylate), EMA (ethyl methacrylate), n-BMA (n-butyl methacrylate), IBMA (isobutyl methacrylate), t-BMA (tert-butyl methacrylate), EHMA (2-ethylhexyl methacrylate), LMA (lauryl methacrylate), TDMA (tridecyl methacrylate), SMA (stearyl methacrylate), CHMA (cyclohexyl methacrylate), BZMA (benzyl methacrylate), IBXMA (isobornyl methacrylate), MAA (methacrylic acid), HEMA (2-hydroxyethyl methacrylate), HPMA (2-hydroxypropyl methacrylate), DMMA (dimethylaminoethyl methacrylate), DEMA (diethylaminoethyl methacrylate), GMA (glycidyl methacrylate), THEMA (tetrahydrofurfuryl methacrylate), AMA (allyl methacrylate), ETMA (ethoxyethyl methacrylate), 3FMA (trifluoroethyl methacrylate), 8FMA (octafluoropentyl methacrylate), IBA (isobutyl acrylate), TBA (tert-butyl acrylate), LA (lauryl acrylate), CEA (cetyl acrylate), STA (stearyl acrylate), CHA (cyclohexyl acrylate), BZA (benzyl acrylate),IBXA (Isobornylacrylat), 2-MTA (2-Me- thoxyethylacrylat), ETA (2-Ethoxyethylacrylat), EETA (Ethoxyethoxyethylacrylat), PEA (2-Phenoxyethylacrylat), THEA (Tetrahydrofurfurylacrylat), HEA (2-Hydroxyethylacrylat), HPA (2-Hydroxypropylacrylat), 4HBA (4-Hydroxybutylacrylat), DMA (Dimethylaminoethylacrylat), 3FA (Trifluorethylacrylat), 17FA (Heptadecafluorodecylacrylat), 2-PEA (2-Phenoxyethylac- rylat), TBCHA (4-tert-butylcyclohexylacrylat), EHA (2-Ethylhe- xylacrylat), 3EGMA (Triethylenglycolmonomethacrylat) , Isode- cyl-methacrylat, Isodecyl-acrylat, Trimethylcyclohexylmethac- rylat, Trimethylcyclohexylacrylat, Tert-butyl-cyclohexylac- rylat, SR256 ((2- (2-Ethoxyethoxyethylacrylat)), SR257C (C16- C18 alkylacrylat), CD278 (Diethylenglycol-monobutyletherac- rylat), SR440 (Iso-octylacrylat), SR484 (Octyldecylacrylat), Adamantylmethacrylat (CAS=16887-36-8), Dicyclopentanylmethac- rylat (CAS=34759-34-7), Dicyclopentenyloxyethyl methacrylat (CAS=68586-19-6),Dicyclopentanyl acrylate (CAS=79637-74-4), dicyclopentenyloxyethyl acrylate (CAS=65983-31-5) and dicyclopentanyl methyl acrylate (CAS=93962-84-6). Other difunctional and multifunctional monomers are preferably selected from DDDMA (1,1O-decanediol dimethacrylate), DDDA (1,10-decanediol diacrylate), NDDA (1,9-nonanediol diacrylate), NDDMA (1,9-nonanediol dimethacrylate), HDDMA (1,6-hexanediol dimethacrylate), HDDA (1,6-hexanediol diacrylate), PDDMA (1,5-pentanediol dimethacrylate), PDDA (1,5-pentanediol diacrylate), BDDMA (1,4-butanediol dimethacrylate), BDDA (1,4-butanediol diacrylate), PRDMA (1,3-propanediol dimethacrylate), PRDA (1,3-propanediol diacrylate), GDMA,

[0066] (Glycerindimethacrylat), PEG400DA (Polyethylenglycol 400 Diac- rylat), PEG400DMA (Polyethylenglycol 400 Dimethacrylat), PEG300DA (Polyethylenglycol 300 Diacrylat), PEG300DMA (Polyethy- lenglycol 300 Dimethacrylat), PEG200DA (Polyethylenglycol 200 Diacrylat), PEG600DA (Polyethylenglycol 600 Diacrylat), NPG(PO)2DA (Propoxyliertes (2) Neopentylglycol Diacrylat), NPG(PO)2DMA (Propoxyliertes (2) Neopentylglycol Dimethac- rylat), EGDMA (Ethylenglycoldimethacrylat), EGDA (Ethylengly- coldiacrylat), TEGDMA (Triethylenglycoldimethacrylat), TEDA (Triethylenglycoldiacrylat), 4EGDMA (Tetraethylenglycoldime- thacrylat), 4EGDA (Tetraethylenglycoldiacrylat), BGDMA (1,3— Butylenglycoldimethacrylat ), BGDA (1,3-Butylenglycoldiac- rylat), DEGDMA (Diethylenglycoldimethacrylat), DEGDA (Diethyl- englycoldiacrylat), NPG-DMA (Neopentylglycoldimethacrylat), NPG-DA (Neopentylglycoldiacrylat), TPGDMA (Tripropylenglycol- dimethacrylat), TPGDA (Tripropylenglycoldiacrylat), SR341 (3- Methyl-1,5-pentandioldiacrylat) , CD536 (Dioxaneglycoldiac- rylat), TMPTMA (Trimethylolpropantrimethacrylat), TMPTA, Tri- methylolpropantriacrylat , DTMPTMA (Di-Trimethylolpropan-tetra- methacrylat); DTMPTA (Di-Trimethylolpropan-tetraacrylat); DiPENTMA (Di-Pentaerythritol-pentamethacrylat; DiPENTA (Di- Pentaerythritol-pentaacrylat ), DPEHMA (Di-Pentaerythritol-he- xamethacrylat), DPEHA (Di-Pentaerythritol-hexaacrylat, Miramer M340 (Pentaerythritoltriacrylat), SR494 (Ethoxyliertes Pen- taerythritoltetraacrylat ), Miramer M4004 (Pentaerythritol-n-EO tetraacrylate), SR593 (Ethoxyliertes Pentaerythritoltriac- rylat), ethoxyliertes Trimethylolpropan-trimethacrylat, ethoxyliertes Trimethylolpropan-triacrylat, propoxyliertes Trimethylolpropan-trimethacrylat , propoxyliertes Trimethylolp- ropan-triacrylat, ethoxyliertes Pentaerythritol-trimethac- rylat, ethoxyliertes Pentaerythritol-triacrylat, ethoxyliertes Pentaerythritol-tetramethacrylat , ethoxyliertes Pentaerythri- tol-tetraacrylat,ethoxyliertes Di-Pentaerythritol-trimethac- rylat, ethoxyliertes Di-Pentaerythritol-triacrylat, ethoxy- liertes Di-Pentaerythritol-tetramethacrylat, ethoxyliertes Di- Pentaerythritol-tetraacrylat , ethoxyliertes Di-Pentaerythri- tolpentamethacrylat, ethoxyliertes Di-Pentaerythritol-pentaac- rylat, ethoxyliertes Di-Pentaerythritolhexamethacrylat, ethoxyliertes Di-Pentaerythritol-hexaacrylat, propoxyliertes Pentaerythritol-trimethacrylat , propoxyliertes Pentaerythri- tol-triacrylat, propoxyliertes Pentaerythritol-tetramethac- rylat, propoxyliertes Pentaerythritol-tetraacrylat, propxy- liertes Di-Pentaerythritol-trimethacrylat, propoxyliertes Di- Pentaerythritol-triacrylat , propoxyliertes Di-Pentaerythritol- tetramethacrylat, propoxyliertes Di-Pentaerythritol-tetraac- rylat, propoxyliertes Di-Pentaerythritolpentamethacrylat, propxyliertes Di-Pentaerythritol-pentaacrylat, propoxyliertes Di-Pentaerythritolhexamethacrylat , propoxyliertes Di-Pen- taerythritol-hexaacrylat,Miramer M320 (Glycerin propoxylated triacrylate), SR 9019 (Propoxylated Glycerol triacrylate), SR 9020 (Propoxylated Glycerol triacrylate), SR 9021 (Highly propoxylated Glycerol triacrylate), Genomer 3364 (Modified acrylated polyether polyol), SR 9041 (Pentaacrylate ester). The other mono-, di-, and multifunctional monomers can be included alone or in mixtures.

[0067] Preferred other monomers are triethylene glycol dimethacrylate (TEGDMA), tripropylene glycol diacrylate (TPGDA), 2-hydroxyethyl acrylate (HEA), dicyclopentanyl methyl acrylate (TCDA) and mixtures thereof.

[0068] It is preferred that one or more of the following basic monomers are present in the following mass proportions, based on the total mass of the monomer mixture:

[0069] Base monomer M1 from 2 to 75% by weight, preferably from 5 to 68% by weight, more preferably from 13 to 63% by weight, even more preferably from 15 to 52% by weight;

[0070] Base monomer M2 from 5 to 96 wt.%, preferably from 12 to 65 wt.%, more preferably from 30 to 63.5 wt.%, even more preferably from 30 to 52 wt.%; base monomer M3 from 0 to 75 wt.%, preferably from 0.1 to 65 wt.%, more preferably from 12 to 65 wt.%, even more preferably from 12 to 64 wt.%.

[0071] Furthermore, the other monomers can be present in a mass fraction of 0-15 wt.%, preferably 0.1-15 wt.%, more preferably 1-10 wt.%, more preferably 1-4 wt.%, even more preferably 1-2 wt.%, based on the total mass of the monomer mixture.

[0072] It is preferred that the monomer mixture comprises or consists of the base monomers M1 and M2 in a mass fraction of 25 wt.% or more, more preferably of 30 wt.% or more, even more preferably of 40 wt.% or more, further preferably of 50 wt.% or more, even more preferably of 60 wt.% or more, even more preferably of 70 wt.% or more, even more preferably of 80 wt.% or more, even more preferably of 90 wt.% or more, based on the total mass of the monomer mixture.

[0073] According to the invention, it is preferred that a mass ratio Y = m(M2) / m(Ml) of the base monomers M2 to Ml is 0.5 < Y < 20, preferably 0.6 < Y < 10, more preferably 0.95 < Y < 5.

[0074] The monomer mixture may comprise or consist of the base monomers M1, M2 and M3 in a mass fraction of 80 to 100 wt.%, preferably 85 to 100 wt.%, more preferably 87 to 100 wt.%, even more preferably 100 wt.%, based on the total mass of the monomer mixture.

[0075] According to the invention, it is preferred that the monomer mixture does not contain any monomer having a bisphenol A structure. In particular, it does not contain 2,2-bis[4-(2-hydroxy-3-(meth)acryloxypropoxy)phenyl]propane (BisGMA) and / or ethoxylated bisphenol A di(meth)acrylate (BisEMA). The same applies to the polymerizable dental material.

[0076] In one embodiment, it is preferred that the monomer mixture does not contain any monomer selected from low-molecular-weight and low-viscosity mono- and di(meth)acrylates. In particular, no monomer with a viscosity at a temperature of 23°C of less than 0.05 Pas and / or with partial water solubility is contained. In particular, no di(meth)acrylates with an oligo[ethyleneoxy] group or a linear or branched C1-C10 alkylene group are present in the monomer mixture. More preferably, the monomer mixture is free of hexanediol diacrylate (HDDA), hexanediol dimethacrylate (HDDMA), triethylene glycol diacrylate (TEGDA), and / or triethylene glycol dimethacrylate (TEGDMA). The same applies to the polymerizable dental material.

[0077] The viscosity of monomers or organic resins is regularly specified by the manufacturer and can be determined using a viscometer (e.g., Kinexus Pro from Malvern Instruments Ltd.). A plate-on-plate geometry with an upper plate diameter of 25 mm and a gap width of 0.1 mm was used. A shear stress range of 0.1 Pa to 50 Pa was covered during the measurement. The value at 50 Pa shear stress was used for the evaluation. The measurement was carried out at a temperature of 23°C, which was monitored and kept constant by the device's internal temperature control.

[0078] The monomer mixture according to the invention preferably has a viscosity of 0.2 to 10, more preferably 1 to 6 Pa s at a temperature of 23°C. The invention has the advantage that the monomer mixture according to the invention and consequently also the polymerizable dental material according to the invention overcome the aforementioned disadvantages of the prior art. The monomer mixture and the polymerizable dental material can be produced from base monomers that are readily available and which also have a reduced toxicity potential. The use of the monomer mixture according to the invention for producing a dental material leads to reduced polymerization shrinkage while simultaneously maintaining good mechanical properties of the resulting dental material.In particular, the monomer mixture can be used to obtain dental materials, especially dental composites, with improved volume shrinkage and flexural strength, as well as a good elastic modulus. This is surprising given the molecular sizes and structures of the base monomer M1, as one would expect a reduced crosslinking density and flexural strength.

[0079] Preferably, the monomer mixture and the polymerizable dental material therefore contain no monomers or other compounds with structural elements derived from bisphenol A and also no low-molecular mono- and di(meth)acrylates with partial water solubility, in particular no TEGDMA.

[0080] The invention further relates to a monomer mixture for producing a dental material, comprising: a. at least two or more base monomers M1 represented by the following empirical formula 1:

[0081] K n U m (O-S-PG)o (Formula 1), where PG = a polymerizable group selected from -OOC- CH=CH2 and -OOC-C (CH3)=CH2;

[0082] S = a spacer group selected from unbranched and branched alkylene with Cl-ClO carbon atoms, which may additionally contain oxygen and / or -OOC- in the carbon chain, preferably ethylene;

[0083] 0 = oxygen;

[0084] U = a group represented by the following formula 2:

[0085] -CO-NH-A-NH-CO- (Formula 2), where

[0086] A = a group selected from a divalent aromatic or aliphatic C6-C20 hydrocarbon group, preferably a divalent aliphatic C6-C13 hydrocarbon group, represented by the following formula 6: (Formula 6), where the two indicated bonds (ie the broken lines) each represent the bonding sites to the nitrogen atoms of formula 2; K = a group represented by the following formula 3:

[0087] T(O) S [((OR) r )O]t (Formula 3), where

[0088] T = a trivalent hydrocarbon group having C3-C7 carbon atoms, preferably a trivalent hydrocarbon group represented by the following formula 5: (Formula 5), ​​where the three indicated bonds (ie the broken lines) represent the bonding sites to the oxygen atoms of formula 3,

[0089] 0 = oxygen,

[0090] R = each independently selected from an ethylene group, a 1,2-propylene group, a 1,3-propylene group and a mixture thereof, preferably a 1,2-propylene group, r = each independently 1-12, preferably 1-

[0091] 9, even more preferably 1-6, s = 0 or 1, preferably 0, t = 2 or 3, preferably 3, where the condition must be met that s+t = 3; n = 1-9, preferably 1-7, more preferably 1-5; where the conditions must be met that m = 2n+1 and o = n+2; b. optionally at least one base monomer M2 of the following formula 4:

[0092] PG'-S'-A'-S'-PG' (Formula 4), where

[0093] PG' = a polymerizable group selected from 00C-CH=CH2 and -OOC-C(CH3)=CH2;

[0094] S' = a spacer group selected from unbranched and branched alkylene with Cl-ClO carbon atoms, which may additionally contain oxygen and / or - 00C- in the carbon chain, is preferably methylene, or S' is omitted;

[0095] A' = an aliphatic polycyclic group, preferably an aliphatic tricyclic hydrocarbon group in which one or more hydrogen atoms can each be replaced independently of one another by C 1 -C 4 alkyl radicals, C 1 -C 4 alkoxy radicals, fluorine atoms, chlorine atoms or trifluoromethyl groups, more preferably tricyclodecanylene, even more preferably tricyclo[5.2.1.0 / 2,6]decanylene. The monomer mixture preferably contains several base monomers Ml, more preferably more than two base monomers Ml, further preferably more than three base monomers Ml, even more preferably more than four base monomers Ml, even more preferably more than five base monomers Ml, etc. It is preferably a mixture which, in addition to base monomers, also comprises base oligomers. According to the invention, such a mixture is also referred to as a mixture of base monomers Ml.

[0096] It is preferred that, in addition to the base monomer Ml with n = 1 (i.e., a monomer), the mixture also contains at least one base monomer Ml with n greater than 1 (i.e., an oligomer). The mass fraction of the base monomer(s) Ml with n greater than 1, which can be determined by fractionation by means of gel permeation chromatography using a refractive index detector (measurement with visible light), is preferably 5-70 wt.%, more preferably 10-60 wt.%, even more preferably 15-50 wt.%, based on the total mass of all base monomers Ml of a monomer / oligomer series of n = 1-9.

[0097] The distribution of the base monomers Ml with respect to n can vary widely. It may be that the base monomers Ml in which n = 2-5 or n = 2-4 have the highest mass fraction relative to the total mass fraction of the base monomers Ml. However, it may also be the case that the base monomer(s) Ml with n = 1 has the highest mass fraction compared to each individual base monomer Ml with n = 2-9 contained in the monomer mixture.

[0098] The basic monomers Ml with n > 1 are present as basic monomers with n = 2-9, preferably with n = 2-7, more preferably with n = 2-5.

[0099] In one embodiment, all base monomers Ml of a monomer / oligomer series with n = 1-9, preferably with n = 1-7, more preferably with n = 1-5, can be present alongside one another. This means that if at least one compound is present for each n from 1-9, at least 9 compounds (i.e., one monomer for n = 1 and eight oligomers for n = 2, 3, 4, etc.) would be present in the monomer mixture (or monomer / oligomer mixture). For n = 1-7, at least 7 compounds (i.e., one monomer and six oligomers) would be present in the monomer mixture, and for n = 1-5, at least 5 compounds (i.e., one monomer and four oligomers) would be present.

[0100] Furthermore, the monomer mixture for producing a dental material comprising at least two or more base monomers M1 is subject to essentially the same features and conditions as for the monomer mixture according to the invention for producing a dental material comprising at least one base monomer M1.

[0101] The invention further relates to a use of the monomer mixture according to the invention, preferably according to one of claims 1 to 10, for producing a polymerizable dental material, preferably a dental composite, core build-up, root canal filling, filling, underfilling, fixing, crown, bridge, restoration and / or prosthesis material.

[0102] In a preferred embodiment, it is a radically polymerizable dental material.

[0103] The invention also relates to a polymerizable dental material comprising: a) the monomer mixture according to the invention, preferably according to one of claims 1 to 10; b) optionally at least one initiator or one initiator system for the polymerization; c) optionally fillers; d) optionally additives customary in dentistry.

[0104] The polymerizable dental material can be in the form of a kit. The kit can contain one or more components. In a multi-component kit or system, the dental material is prepared immediately before use by mixing the components in the specified mixing ratio and then curing. b) Initiator(s)

[0105] Suitable initiators or initiator systems are capable of initiating polymerization reactions, preferably free-radical polymerization reactions. Such initiators or initiator systems are known to those skilled in the art.

[0106] Initiator systems consist of at least one initiator and at least one other compound, such as a coinitiator. These can be distributed among various components of the polymerizable dental material. The dental material according to the invention can be cured thermally, chemically, or photochemically, ie, by irradiation with UV and / or visible light.

[0107] Suitable initiators can be, for example, photoinitiators. These are characterized by the fact that they can cure the material by absorbing light in the wavelength range from 300 nm to 700 nm, preferably from 350 nm to 600 nm, and particularly preferably from 380 nm to 500 nm, and optionally by additional reaction with one or more coinitiators. Preferably, phosphine oxides, acylphosphine oxides, bisacylphosphine oxides and derivatives thereof, acylgermanes, as described for example in EP2649981A1, W02017 / 055209A1 and EP3153150A1, benzoin ethers, benzil ketals, acetophenones, benzophenones, thioxanthones, bisimidazoles, metallocenes, fluorones, a-dicarbonyl compounds, aryldiazonium salts, arylsulfonium salts, aryliodonium salts, ferrocenium salts, phenylphosphonium salts or a mixture of these compounds are used here.

[0108] Particularly preferred are diphenyl-2,4,6-trimethylbenzoylphosphine oxide, phenyl-bis-2,4,6-trimethylbenzoylphosphine oxide, benzoin, benzoin alkyl ethers, benzil dialkyl ketals, a-hydroxyacetophenone, dialkoxyacetophenones, a-aminoacetophenones, isopropylthioxanthone, camphorquinone, phenylpropanedione, 5,7-diiodo-3-butoxy-6-fluorone, (eta-6-cumene)(eta-5-cyclopentadienyl)iron hexafluorophosphate, (eta-6-cumene)(eta-5-cyclopentadienyl)iron tetrafluoroborate, (eta-6-cumene)(eta-5-cyclopentadienyl)iron hexafluoroantimonate, substituted diaryliodonium salts, Triarylsulfonium salts or a mixture of these compounds are used.

[0109] Preferred co-initiators for photochemical curing are tertiary amines, borates, organic phosphites, diaryliodonium compounds, thioxanthones, xanthene, fluorenes, fluorones, α-dicarbonyl compounds, dicarbonyl systems as described in WO2021 / 048313A1, condensed polyaromatics, or a mixture of these compounds. Particular preference is given to using N,N-dimethyl-p-toluolidine, N,N-dialkylalkylanilines, N,N-dihydroxyethyl-p-toluidine, 2-ethylhexyl-p-(dimethylamino)benzoate, ethyl-p-(dimethylamino)benzoate, butyrylcholine triphenylbutyl borate, or a mixture of these compounds. So-called thermal initiators can also be used as initiators, which can cause the material to harden by absorbing thermal energy at elevated temperatures.In this case, inorganic and / or organic peroxides, inorganic and / or organic hydroperoxides, α,α'-azobis(isobutyroethyl ester), α,α'-azobis(isobutyronitrile), benzpinacols, or a mixture of these compounds are preferably used. Diacyl peroxides such as benzoyl peroxide or lauroyl peroxide, cumene hydroperoxide, benzpinacol, 2,2'-dimethylbenzpinacol, or a mixture of these compounds are particularly preferred.

[0110] For chemical curing at room temperature, a redox initiator system is generally used, which consists of one or more initiators and a coinitiator or coinitiators serving as activator. For reasons of storage stability, individual components of an initiator system are incorporated into spatially separate parts of the dental material according to the invention, i.e. a multi-component, preferably a two-component material is present. The initiator or initiators used are preferably inorganic and / or organic peroxides, inorganic and / or organic hydroperoxides, barbituric acid derivatives, malonyl sulfamides, protonic acids, Lewis or Broensted acids or compounds that release such acids, carbenium ion donors such as methyl triflate or triethyl perchlorate or a mixture of these compounds. The coinitiator or coinitiators used are preferably tertiary amines, heavy metal compounds, in particular compounds of the 8thand Group 9 of the Periodic Table ("iron and copper group"), compounds with ionically bound halogens or pseudohalogens such as quaternary ammonium halides, weak Broenstedt acids such as alcohols and water, or a mixture of these compounds are used. The dental material according to the invention can also contain any conceivable combination of the initiators and coinitiators described above. One example of this is so-called dual-curing dental materials, which contain both photoinitiators and optionally the corresponding coinitiators for photochemical curing, as well as initiators and corresponding coinitiators for chemical curing at room temperature.

[0111] The polymerizable dental material according to the invention is preferably light-curing. In a preferred embodiment, camphorquinone (CQ) is present as an initiator and 2-ethylhexyl p-(dimethylamino)benzoate (EHA) or ethyl p-(dimethylamino)benzoate is present as a co-initiator. c) Fillers

[0112] The polymerizable dental material according to the invention may contain other additives commonly used in dentistry. The filler particles are not restricted to a specific particle shape. Rather, fillers with a spherical, flaky, platelet-like, needle-like, leaf-like, or irregular shape can be used very well. The filler particles preferably have an average particle diameter of 5 nm to 100 pm, more preferably 5 nm to 50 pm.

[0113] Suitable fillers can be selected from a wide variety of materials commonly used in dental products. The choice of filler can, for example, adjust the fluidity, viscosity, consistency, color, radiopacity, and mechanical stability of the dental material. Based on their chemical nature, fillers can be roughly divided into three different classes: inorganic fillers, organic fillers, and organic-inorganic composite fillers. The fillers can be used not only individually but also in combination with one another.

[0114] Ground powders of natural or synthetic glasses or crystalline inorganic substances in various sizes and states (monodisperse, polydisperse) can be used as inorganic fillers. Suitable materials include quartz, cristobalite, glass ceramics, feldspar, barium silicate glasses (such as those available under the trade names Kimble RAY-SORB T3000, Schott 8235, Schott GM27884, Schott G018-053, and Schott GM39923), barium fluorosilicate glasses, strontium silicate glasses, strontium borosilicate glasses (such as those available under the trade names RAY-SORB T4000, Schott G018-093, Schott G018-163, and Schott GM32087), lithium aluminum silicate glasses, barium glasses, calcium silicates, sodium aluminum silicates, fluoroaluminosilicate glasses (such as those available under the trade names Schott G018-091 and Schott G018-117), zirconium or cesium boroaluminosilicate glasses (such asavailable under the trade names Schott G018-307, G018-308 and G018-310), zeolites and apatites. The fillers preferably have an average particle size d50 of 0.01-15 pm, preferably an average particle size d50 of 0.2-5 pm and particularly preferably an average particle size of 0.2-1.5 pm. It may be preferred that the average particle size d50 is between 0.1-0.5 pm. In such cases, it is particularly preferred that the average particle size d90 is less than 1.0 pm. Furthermore, discrete, non-agglomerated, non-aggregated, organically surface-modified nanoparticles can be used in order to achieve a more uniform filling of the dental material and to increase the hardness and abrasion resistance.

[0115] In this context, nanoparticles are understood to be spherical particles with an average particle size of less than 200 nm. The average particle size is preferably less than 100 nm and particularly preferably less than 60 nm. The smaller the nanoparticles, the better they can fulfill their function of filling the cavities between the coarser particles. The materials for the nanoparticles are preferably oxides or mixed oxides and are preferably selected from the group consisting of oxides and mixed oxides of the elements silicon, titanium, yttrium, strontium, barium, zirconium, hafnium, niobium, tantalum, tungsten, bismuth, molybdenum, tin, zinc, ytterbium, lanthanum, cerium, aluminum, and mixtures thereof. The preferred oxide nanoparticles are not agglomerated. To enable good integration of the nanoparticles into the polymer matrix of a composite material, the surfaces of the nanoparticles are organically modified.The surface treatment of the fillers is preferably carried out with a silanizing agent. Methacryloxypropyltrimethoxysilane is particularly suitable as an adhesion promoter. Commercially available nanoscale, non-agglomerated, and non-aggregated silica sols that can be used are sold, for example, under the names "NALCO COLLOIDALSILICAS" (Nalco Chemical Co.), "Ludox colloidal silica" (Grace), or "Highlink OG" (Clariant).

[0116] Submicron fillers or microfillers consisting of agglomerated, nano-scale particles can also be used, especially if their specific surface area (determined according to Brunauer, Emmet, Teller) is in the range between 100 and 400 m 2 / g. Fumed silica or wet-precipitated silica are preferred. Suitable, applicable non-surface-treated silica filler products are commercially available under the names AEROSIL™ ("0X50", "90", "130", "150", "200", "300" and "380", "R8200" from Evonik Industries AG, Essen, Germany), Cab-O-Sil ("LM-150", "M-5", "H-5", "EH-5" from Cabot Corp., Tuscola, IL), HDK™ ("S13", "V15", "N20", "T30", "T40" from Wacker-Chemie AG, Munich, Germany), and Orisil™ ("200", "300", "380" from Orisil, Lviv, Ukraine).

[0117] Particularly advantageous abrasion and gloss resistance properties can be achieved by using aggregated, nanoscale particles based on mixed oxides of silicon dioxide and zirconium dioxide in the dental material. A suitable filler can be manufactured using a process described, for example, in US Pat. No. 6,730,156 (Example A). The filler produced in this way can then be surface-treated using a method as described in US Pat. No. 6,730,156 (e.g., Manufacturing Example B).

[0118] The aggregated fillers preferably have an average secondary particle size of 1-15 pm, preferably an average secondary particle size of 1-10 pm and particularly preferably an average secondary particle size of 2-5 pm.

[0119] The use of spherical submicroparticles based on silicon-zirconium mixed oxides, as described in DE 19524362 Al or US2020 / 0121564 Al, can be particularly advantageous for achieving high fill levels with simultaneous high aesthetics and abrasion stability.

[0120] In addition, significant amounts of selected radiopaque fillers may be present. The addition of radiopaque particles to the dental material is advantageous because it allows one to distinguish between healthy tooth structure and the restoration. Suitable radiopaque fillers contain particles of metal oxides, metal fluorides, or barium sulfate. Oxides and fluorides of heavy metals with an atomic number greater than 28 are preferred. The metal oxides and fluorides should be selected so that they influence the color of the restoration as little as possible. Metal oxides and fluorides with an atomic number greater than 30 are more suitable. Suitable metal oxides are oxides of yttrium, strontium, barium, zirconium, hafnium, niobium, tantalum, tungsten, bismuth, molybdenum, tin, zinc, lanthanides (elements with an atomic number from 57 to 71), cerium, and combinations thereof. Suitable metal fluorides include yttrium trifluoride and ytterbium trifluoride.Particularly preferred here are irregularly shaped or spherical YbFa or YFa particles with an average primary particle size of 40 nm to 1.5 pm, and particularly preferred are core-shell combination products consisting of a YF3 or YbFa core and a SiO2 shell, with the SiO2 shell surface most preferably being silanized. In particular, such a core-shell combination product has a refractive index of 1.48 to 1.54 and a measured average particle size of the agglomerated particles between 0.5 and 5 pm.

[0121] Examples of suitable organic fillers are filled and unfilled, powdered polymers or copolymers based on polymethyl methacrylate (PMMA), polyethyl methacrylate, polypropyl methacrylate, polybutyl methacrylate (PBMA), polyvinyl acetate (PVAc), polyethylene glycol (PEG), polypropylene glycol (PPG), polyvinyl alcohol (PVA), polyurethane (PU), polyurea, methyl methacrylate-ethyl methyl acrylate copolymer, ethylene vinyl acetate copolymer, and styrene-butadiene copolymer. Furthermore, the organic filler may contain a biologically active component, a specific pigment, a polymerization initiator, a stabilizer, or something similar added during the manufacturing process. The organic fillers may be used alone or as mixtures.

[0122] Advantageous polishing properties combined with a higher filler content can be achieved in dental materials using so-called organic-inorganic composite fillers. These fillers are produced by combining a polymerizable monomer with an inorganic filler to form a paste, subsequently curing it through polymerization, and then finely grinding it before being used as a filler. Microfillers are preferably used as the inorganic filler. After grinding, the fillers preferably have an average particle size of 0.05–100 μm, preferably an average particle size of 0.5–50 μm, and particularly preferably an average particle size of 1–30 μm.

[0123] It is preferred that the fillers in the dental materials are surface-modified. For this purpose, the described inorganic or organic-inorganic composite fillers, for example, are subjected to a surface treatment before use to improve the compatibility, affinity, and incorporability of the fillers into the resin mixture. This treatment organically modifies the surfaces of the inorganic particles, meaning the surfaces have organic structural elements. All methods known to those skilled in the art can be used for this purpose. Silanizing agents are preferred for inorganic fillers that bear OH groups on the surface.Examples include γ-methacryloxyalkyltrimethoxysilane (number of C atoms between the methacryloxy group and the silicon atom: 3 to 12), γ-methacryloxyalkyltriethoxysilane (number of C atoms between the methacryloxy group and the silicon atom: 3 to 12), or silicone compounds such as vinyltrimethoxysilane, vinylethoxysilane, and vinyltriacetoxysilane. Methacryloxypropyltrimethoxysilane is particularly preferred as a silanizing agent.

[0124] Inorganic fillers that carry few or no OH groups on their surface are preferably surface-treated with other surface modifiers, such as titanates, aluminates, zircoaluminates, surfactants, fatty acids, organic acids, inorganic acids, or metal alkoxides. Organic compounds that carry N-, P-, S-, and / or O-containing functional groups (e.g., polyols, sulfoxides, phosphinic acid esters, phosphonic acid esters, trialkylphosphines, carboxylic acids, and carboxylic acid esters) are particularly preferred as surface modifiers for salts of barium, strontium, and rare earth metals. 10-Methacryloyloxydecyl dihydrogen phosphate is particularly suitable.

[0125] Particularly in the case of agglomerated silicon dioxide-based nanofillers, the surface modifications can consist of radically reactive groups, such as the aforementioned methacryloyloxyalkyl groups, or radically unreactive groups. Suitable unreactive groups include trimethylsilyl, dimethylsilylene, or methylsilylidene groups, which can be applied to the surface by silanization, e.g., with hexamethyldisilazane, dimethyldimethoxysilane, or methyltrimethoxysilane. Suitable unreactive surface-modified agglomerated nanofillers are commercially available, for example, under the names Aerosil R8200, Aerosil R812S, Aerosil R805, Aerosil R202, Aerosil R974 (Evonik Industries AG, Essen, Germany) or HDKH2000, HDKH200 / 4 (Wacker Chemie, Burghausen, Germany). Furthermore, the agglomerated nanofillers can preferably be modified with groups that are reactive in radical processes, for example methacryloyl groups.A commercially available product of a radically reactively modified agglomerated nanofiller is available under the name Aerosil R7200 (Evonik Industries AG, Essen, Germany).

[0126] Preferably, the agglomerated nanofillers can be largely deagglomerated, as described, for example, in EP1720206.

[0127] A dental material according to the invention can contain a proportion of filler particles between 0 and 95 wt.%, preferably from 1 to 95 wt.%, based on the total mass of the polymerizable dental material. The amount of the filler fraction is selected depending on the indication of the dental product. For example, the highest possible filler quantities are used for stable, moldable filling composites, for dental compositions for the production of inlays, onlays or overlays, and for compositions for the production of dental CAD-CAM materials to be processed subtractively. As a rule, these compositions have filler contents of 75 wt.% to 92 wt.%, based on the total composition. Flowable dental composites, luting composites, core build-up materials, crown and bridge materials, and dental materials to be processed using stereolithographic methods generally have an average filler range of 40 to 80 wt.-%, based on the total composition, whereas fillers in the range of 1 to 40 wt.%, based on the total composition, are used for dental varnishes, dental sealing materials, dental infiltrants, low-viscosity dental materials processed by stereolithographic techniques, and dental adhesives. The filler ranges given above are only guidelines; deviations may occur depending on the filler selection. d) Common dental additives.

[0128] The polymerizable dental material according to the invention may contain other additives commonly used in dentistry. Common dental additives are known to those skilled in the art; preferred additives are inhibitors, stabilizers, accelerators, dyes, fluoridating agents, remineralizing agents, radiopaque agents, and film formers.

[0129] Inhibitors and stabilizers serve primarily to prevent premature polymerization. They are substances that react with reactive radicals to form more stable scavenger products. The addition of inhibitors or stabilizers improves the storage stability of compositions yet to be cured. Inhibitors can also be used to adjust the processing time of curing systems within a suitable range. Suitable inhibitors include phenol derivatives such as hydroquinone monomethyl ether (HQME) or 2,6-di-tert-butyl-4-methylphenol (BHT). Further inhibitors, such as tert-butylhydroxyanisole (BHA), 2,2-diphenyl-l-picrylhydrazyl, galvinoxyl, and triphenylmethyl radicals, 2,3,6,6-tetramethylpiperidinyl-l-oxyl radicals (TEMPO), as well as derivatives of TEMPO or phenothiazine and derivatives of this compound, are described in EP 0783880 B1. Alternative inhibitors can be found in DE 10119831 A1 or EP 1563821 A1.

[0130] The polymerizable dental material may contain, in particular, 2,6-di-tert-butyl-4-methylphenol (BHT) as a stabilizer.

[0131] The dental material according to the invention can contain UV stabilizers as a conventional dental additive. UV stabilizers serve, in particular, to stabilize the dental material against degradation or discoloration caused by UV radiation. Examples of UV absorbers are 2-hydroxy-4-methoxybenzophenone, phenyl salicylate, 3-(2'-hydroxy-5'-methylphenyl)benzotriazole, or diethyl 2,5-dihydroxyterephthalate.

[0132] The dental material according to the invention can contain one or more fluoride-releasing substances in finely divided, particulate form as a dental additive. Fluoride-releasing substances can be water-soluble fluorides such as sodium fluoride or amine fluoride. Other suitable fluoride-releasing substances are poorly soluble fluorides of main group 2. Fluoride-containing glasses are also suitable fluoride sources. Other suitable additives are finely particulate substances that release calcium and / or phosphate and thereby have a remineralizing effect. Suitable remineralizing substances are calcium phosphate compounds such as hydroxyapatite, brushite, monocalcium phosphate, fluorapatite, and bioactive glasses such as those mentioned in DE10111449A1, DE102005053954A1, or US9517186B2.

[0133] The dental material according to the invention may contain a colorant or colorant mixture selected from fluorescent dyes, fluorescent pigments, organic color pigments, inorganic color pigments and mixtures thereof.

[0134] A fluorescent colorant or pigment is preferably an organic fluorescent dye or an organic fluorescent pigment, in particular a non-polymerizable, organic fluorescent colorant, optionally comprising arylcarboxylic acid esters, such as diethyl 2,5-dihydroxyterephthalate, arylcarboxylic acids, coumarin, rhodamine, naphthalene imide, or derivatives thereof. Inorganic fluorescent pigments can be, for example, CaAl4O7:Mn 2+

[0135] (BaO.98EuO.02)MgAlioOi7, BaMgF4:Eu 2+, Y (1.995)Ce (0.005)SiO5. As color pigments, the dental material according to the invention can comprise organic pigments and inorganic pigments, such as N,N'-bis (3,5-xylyl)perylene-3,4:9,10-bis(dicarbimide), copper phthalocyanine, titanate pigment, in particular chromium antimony titanate (rutile structure), spinel black, in particular pigments based on iron oxide black (FeaO4), where iron is partially substituted by chromium and copper or nickel and chromium or manganese, other iron oxide-based pigments, zinc iron chromium spinel brown spinel, ((Zn,Fe)(Fe,Cr)2O4) cobalt zinc aluminate blue spinel and / or titanium oxide.

[0136] The components in the dental material can be contained in the following mass proportions, based on the total mass of the dental material according to the invention: the monomer mixture from 5 to 99 wt.%, preferably from 10 to 95 wt.%, more preferably from 15 to 85 wt.; the at least one initiator or initiator system for the polymerization from 0 to 5 wt.%, preferably from 0.01 to 5 wt.%; the fillers from 0 to 95 wt.%, preferably from 1 to 95 wt.%, more preferably from 5 to 90 wt.%, even more preferably from 15 to 85 wt.%; the dental additives from 0 to 5 wt.%, preferably from 0.001 to 5 wt.%.

[0137] Preferably, the dental material does not contain a compound with a bisphenol A-based structural element.

[0138] The invention further relates to the dental material according to the invention, preferably according to one of claims 12 to 13, for use in a therapeutic method as a dental composite, filling, underfilling, luting, core build-up, root canal filling, crown, bridge, restoration and / or prosthesis material.

[0139] The invention also relates to a cured dental material produced from the polymerizable dental material according to the invention, in particular according to one of claims 12 to 13.

[0140] The invention may also provide a process for producing at least one, preferably at least two or more, base monomers M1, wherein the process comprises the following steps: a) reacting one or more compounds of the following formula 15:

[0141] T(OH) S [((OR) r )OH]t (Formula 15), where

[0142] T = a trivalent hydrocarbon group with C3-C7 carbon atoms,

[0143] 0 = oxygen,

[0144] R = each independently selected from an ethylene group, a 1,2-propylene group, a 1,3-propylene group and a mixture thereof, preferably a 1,2-propylene group, r = each independently 1-12, preferably 1-9, even more preferably 1-6, s = 0 or 1, preferably 0, t = 2 or 3, preferably 3, wherein the condition must be met that s+t = 3; with one or more diisocyanates of the following formula 16:

[0145] OCN-A-NCO (Formula 16), where

[0146] A = a group selected from a divalent aromatic or aliphatic C6-C2O hydrocarbon group, preferably a divalent aliphatic C6-C13 hydrocarbon group, represented by the following formula 6: (Formula 6) where the two indicated bonds (ie the broken lines) each represent the bonding sites to the nitrogen atoms of formula 2; b) reacting the remaining isocyanate groups of a reaction product from step a) with a compound of the following formula 17:

[0147] HO-S-PG (Formula 17), where

[0148] PG = a polymerizable group selected from -OOC- CH=CH2 and -OOC-C(CH3)=CH2;

[0149] S = a spacer group selected from unbranched and branched alkylene with Cl-ClO carbon atoms, which may additionally contain oxygen and / or - 00C- in the carbon chain, is preferably ethylene.

[0150] The reaction in step a) is preferably carried out in a ratio of a molar amount of the hydroxyl groups xl(OH) to a molar amount of the isocyanate groups x2(NGO) of x2(NGO) / x2(OH), subject to the condition that Xi(NCO) / xi(OH) is > 1, more preferably xi(NCO) / xi(OH) is between 1.5 and 10, even more preferably xi(NCO) / xi(OH) is between 3 and 5.

[0151] Preferably, the reaction in step a) takes place essentially with the formation of urethane groups up to a degree of conversion of at least 95%, more preferably of at least 99%, of all OH groups.

[0152] The reaction in step b) preferably takes place in a ratio of a molar amount of the hydroxyl groups X2(OH) to a molar amount of the isocyanate groups X2(NCO) of X2(OH) / x2(NCO), subject to the condition that X2(OH) / x2(NCO) is > 1, more preferably X2(OH) / x2(NCO) is between 1.0 and 1.4, even more preferably X2(OH) / x2(NCO) is between 1.0 and 1.2. By choosing the ratio xi(NCO) / xi(OH), in particular the ratio of the weight fractions of the base monomer Ml with n = 1 to the weight fraction of the monomers Ml with n > 2 can be controlled.

[0153] The reactions of steps a) and / or b) can take place in a solvent or without solvent. The solvent can be a low-viscosity resin that does not interfere with the reactions. Suitable low-viscosity resins can be those described as monomer M2 and / or other monomers, provided they do not react under the reaction conditions used.

[0154] It may be preferred that a reaction product from step b) (i.e., the base monomer M1 or a mixture of the base monomers M1) is mixed with the other monomers of the monomer mixture according to the invention immediately after completion of the reaction. The other monomers within the scope of the invention include the monomers M2, M3, and the other monomers. Volatile constituents, such as solvents, are then preferably removed only after the addition of the other monomers. Such a procedure has the advantage that the monomer mixture remains low-viscosity and stirrable.

[0155] However, it may also be preferred for the reaction product from step b) to be dried before addition with the other monomers of the monomer mixture according to the invention. This can be advantageous because the excess proportion of the compound of formula 17 can be significantly reduced by the drying process. Drying can be carried out, for example, using a thin-film evaporator. After completion of the drying process, the monomer mixture according to the invention can then be prepared by adding the other monomers and mixing.

[0156] The invention may also relate to a monomer mixture for producing a dental material, comprising at least one, preferably at least two or more base monomers M1, produced by such a process.

[0157] The invention will now be described by way of example with reference to some advantageous embodiments.

[0158] Examples

[0159] For the following examples, the compounds used in Table 1 below were used in particular.

[0160] Table 1: Compounds and substances used in the examples.

[0161] Example of oligourethane acrylate (OPUA)

[0162] A preferred example of a base monomer M1 according to the invention is an oligourethane acrylate (OPUA), which is explained in more detail below. The oligourethane acrylate (OPUA) according to the invention can be obtained, for example, in a mixture with UDA-IPDI (base monomer M3) by reacting a glycerol propoxylate having a number-average degree of propoxylation of 9 per molecule of glycerol with an excess of isophorone diisocyanate and subsequently reacting the excess isocyanate groups with HEA. The monomer mixture thus obtained comprises various OPUAs (as base monomer M1) as well as UDA-IPDI (as base monomer M3) and excess HEA (as other monomer). TPGDA (as other monomer) can also be added to the mixture, which can serve as a diluent resin.

[0163] The OPUA produced in this way (as base monomer Ml) can be described by the following molecular formula 1: KnUm(OS-PG)o (Formula 1), with n = 1-4, m = 3-9 and o = 3-6, where the conditions are met that m = 2n+l and o = n+2, where the proportions of the respective oligomers range from n = 1 to n =

[0164] 4 and individual structural elements of the OPUA produced in this way look as follows:

[0165] The indicated bonds (ie the broken lines) represent the bonding points of the groups to the corresponding partner groups. Thus, the three carbon atoms of group T each bind to the corresponding oxygen atoms of T[((OR) ri-r3)0]t of group K. The carbamoyl carbon atoms -NH-CO- of group U can either bond to an oxygen atom of group -OS-PG and to an oxygen atom of group K (T[((OR)ri-rs)O]t) or bond to two oxygen atoms of different groups K. The oxygen atom of group -OS-PG always bonds to a carbamoyl carbon atom - NH-CO- of group U.

[0166] The bonding situation is shown below as an example for a molecular fragment T- ((OR) r 2)-OUOS-PG.

[0167] The sum rl + r2 + r3 has an average value of 9.

[0168] Synthesis example: Preparation of OPUA in mixture with UDA-

[0169] IPDI

[0170] This article describes a process for producing OPUA as base monomer Ml in a mixture with UDA-IPDI.

[0171] 60 g of glycerol propoxylate 9 are dissolved in 100 ml of toluene and then completely concentrated using a rotary evaporator. This yields glycerol propoxylate 9 with a residual content of approximately 11.6 wt.% toluene, which is considered an inert component for all further syntheses. The weights given below refer to the pure substance, glycerol propoxylate 9.

[0172] 15 ml of dry THF are placed in a three-neck flask equipped with a dropping funnel and reflux condenser with a CaCl2-filled drying tube, with exclusion of water. A g of isophorone diisocyanate are added and dissolved with stirring at room temperature. B g of glycerol propoxylate 9 are added at room temperature. 87.2 μl of a 51.5 g / L solution of Sn-Kat in toluene, dry, are then added while cooling with a water bath and stirred for a further 10 minutes while cooling with water. The mixture is then stirred for 3.5 h at 40°C bath temperature. C g of HEA are added dropwise, and the mixture is stirred for a further 0.5 h at 40°C and then for 62 h at room temperature. IR spectroscopy does not detect any remaining isocyanate groups. The reaction mixture is then applied in a thin layer to an evaporating dish, where it is initially dried in air at room temperature for 2 days.Residual traces of solvent are removed from the mixture over two days at 60°C in a forced-ventilation oven. Colorless to pale yellow, clear, viscous substances are obtained in almost quantitative yield.

[0173] Batches 1 and 2, as shown in Table 3, are obtainable from mixtures 1 and 2 according to Table 2 below.

[0174] Table 2: Mixing ratios for the preparation of batches 1 and 2 containing OPUA 3 shown in Table 3.

[0175] An appropriate amount of TPGDA is additionally added to batch 1.

[0176] Formulation Examples: The batches 1-3 used in the examples were characterized by HPLC-MS and MALDI-TOF. For mixtures 1 and 2, as well as for the isolated OPUA 1 from batch 3, the weight fractions shown in Table 3 were determined by GPC measurement.

[0177] Table 3: Composition and mass ratios of batches 1-3.

[0178] Isolation of an oligomer mixture OPUA 1

[0179] The oligomer mixture OPUA 1 is obtained by column filtration of Mixture 1 through silica gel. In a typical procedure, 33 g of Mixture 1 in 12 ml of a mobile phase consisting of n-heptane / ethyl acetate 60:40 (volume:volume) are applied to a silica gel column (diameter 4.8 cm, length 22 cm) packed in the mobile phase. Components not belonging to OPUA 1 are rinsed down with 3.5 L of the same mobile phase. OPUA 1 is then washed from the column using 1.2 L of ethyl acetate. The product solution is carefully concentrated on a rotary evaporator while introducing air. The low-viscosity solution is applied in a thin layer, and residual solvent is removed by standing in air at room temperature over a period of 17 days.

[0180] Preparation of the resins To produce the resins, monomer mixtures were prepared as shown in Tables 4-6 below, and an initiator system was added to them (all values ​​in % by weight, based on the total mass of the polymerizable dental material). In all examples, the initiator system consisted of the same amounts of camphorquinone (CQ) and 2-ethylhexyl p-(dimethylamino)benzoate (EHA) as a co-initiator. 2,6-Di-tert-butyl-4-methylphenol (BHT) was used as a stabilizer in the same concentration in all mixtures. The resulting resins were homogenized overnight using a stirrer.

[0181] Examples 1 to 8 in Tables 4 and 5 represent monomer mixtures not according to the invention and demonstrate the properties of monomer mixtures and polymerizable dental materials of the prior art. In Comparative Examples 3 to 8, the base monomer Bis-GMA was replaced with other non-inventive, difunctional urethane (meth)acrylates. Although good volume shrinkage values ​​are achieved in Comparative Examples 7 and 8, the flexural strength values ​​are significantly poorer. Comparative Examples 3, 4, 5, and 6 show no improvements in either flexural strength or volume shrinkage.

[0182] Table 4: Composition, volume shrinkage, flexural strength and modulus of elasticity of non-inventive monomer mixtures and corresponding dental material compositions (comparative examples)

[0183] Table 5: Composition, volume shrinkage, flexural strength and modulus of elasticity of non-inventive monomer mixtures and corresponding dental material compositions (comparative examples)

[0184] Examples 9 to 14 in Table 6 correspond to monomer mixtures according to the invention and thus to polymerizable dental materials according to the invention. In all examples, the volume shrinkage is significantly improved compared to the Bis-GMA-TEGDMA resin mixtures (Comparative Examples 1 and 2) and the UDMA-TEGDMA resin mixture (Comparative Example 3). The measured flexural strengths for inventive examples 9-14 are at least equivalent, and in some cases even improved, compared to Examples 1-3, despite significantly reduced shrinkage values. Table 6: Composition, volume shrinkage, flexural strength, and Young's modulus of inventive monomer mixtures and dental material compositions

[0185] Production of dental composites

[0186] Dental composites were prepared according to Table 7 below. In Examples 15-19, monomer mixtures according to the invention were used. In Comparative Example 20, a corresponding dental composite was prepared with a monomer mixture containing BisGMA. To produce the dental composites, a total of 75 wt. % of the dental glass G018-053 from SCHOTT AG (average grain size

[0187] 0.7 μm, 6 wt.% silane), based on the total mass of the dental composite, was added and homogenized using a Speedmixer DAC 400-1 VAC-P (Hauschild, Germany). Degassing was then carried out for 3 min at 20 mbar with continued mixing. Table 7: Composition, volume shrinkage, flexural strength, and Young's modulus of dental composites according to the invention with a filler content of 75 wt.% (Examples 15-19)

[0188] Table 8: Composition, volume shrinkage, flexural strength and modulus of elasticity of a non-inventive dental composite with a filler content of 75 wt.% (Comparative Example 20)

[0189] Determination of flexural strength and Young's modulus Flexural strength and Young's modulus were determined. For this purpose, test specimens were manufactured analogously to ISO 4049:2009. In contrast, the test specimens were produced by irradiation with a HiLite®power light polymerization unit (Heraeus). For this purpose, the dental composites in the test specimens (40 mm x 2 mm x 2 mm) were irradiated for 90 s on both sides. The test specimens were stored in distilled water at 37°C for 24 hours. The flexural strength and Young's modulus were determined using a Zwick universal testing machine (type Z010 or type Z2.5, Zwick-Roell, Germany). The mean value of 6 individual measurements and the standard deviation are given.

[0190] Volume shrinkage

[0191] The volume shrinkage was calculated from the difference in density p of the dental composites before (VA) and 24 hours after (NA) curing. Three samples were measured for each composite, and the mean value was used as the density. To determine the density of the composites after curing, cylindrical test specimens (8 mm diameter and 2 mm height) were produced by irradiation with a HiLite power light polymerization unit (Heraeus). Irradiation took place for 90 s from both sides of the test specimen. These were stored in a dry place at 23°C for 24 hours. A helium gas pycnometer (Accupyc III 1340, Micromeritics Instrument Corporation, USA, GA) was used to measure the density of the cured and uncured composites.

[0192] The volume shrinkage VS was calculated from the following formula:

[0193] VS 100% x (PNA - PVA) / PNA.

[0194] GPC measurement The measurement was carried out on a GPC system (PSS SECcurity GPC System, PSS Polymer Standards Service GmbH, Germany) with column oven and RI detector.

[0195] The following column combination was used to separate the components: guard column VA 50 / 7.7 Nucleogel GP 5 P, separation columns

[0196] VA 300 / 7.7 Nucleogel GPC 104-5 and VA 300 / 7.7 Nucleogel GPC 500-5 (all from Macherey & Nagel). The columns were thermostatted at 20 °C.

[0197] The sample concentration was approximately 1%. 20 μl of sample were injected, and THE (Merck 109731) was used as the mobile phase. The mobile phase flow rate was 0.5 ml / min. The proportions of oligomers and monomers were determined by integrating the respective areas under the measurement curve of the refractive index detector. For peaks that merge into one another, the perpendicular was dropped onto the volume axis at the local minimum of the curve between the peaks, and the intersection of the perpendicular with the volume axis was used as the integration limit.

Claims

Patent claims Monomer mixture for producing a dental material, comprising: a. at least one base monomer M1 of the following empirical formula 1: KnUm(OS-PG)o (Formula 1), where PG = a polymerizable group selected from -OOC-CH=CH2 and -OOC-C(CH3)=CH2; S = a spacer group selected from unbranched and branched alkylene with Cl-ClO carbon atoms, which may additionally contain oxygen and / or -OOC- in the carbon chain, is preferably ethylene; 0 = oxygen; U = a group represented by the following formula 2: -CO-NH-A-NH-CO- (Formula 2), where A = a group selected from a divalent aromatic or aliphatic C6-C20 hydrocarbon group, preferably a divalent aliphatic C6-C13 hydrocarbon group, more preferably is a divalent saturated, cyclic C6-C13 hydrocarbon group; K = a group represented by the following formula 3: T(O) S [((OR) r )O]t (Formula 3), where T = a trivalent hydrocarbon group with C3-C7 carbon atoms, 0 = oxygen, R = is each independently selected from an ethylene group, a 1,2-propylene group, a 1,3-propylene group and a mixture thereof, preferably a 1,2-propylene group, r = is each independently 1-12, preferably 1-9, even more preferably 1-6, s = 0 or 1, preferably 0, t = 2 or 3, preferably 3, where the condition must be met that s+t = 3; n = 1-9, preferably 1-7, even more preferably 1-5; where the conditions must be met that m = 2n+1 and o = n+2; b. at least one base monomer M2 of the following formula 4 : PG'-S'-A'-S'-PG' (Formula 4), where PG' = a polymerizable group selected from OOC-CH=CH2 and -OOC-C(CH3)=CH2; S' = a spacer group selected from unbranched and branched alkylene with Cl-ClO carbon atoms, which may additionally contain oxygen and / or -OOC- in the carbon chain, is preferably methylene, or S' is omitted; A' = an aliphatic polycyclic group, preferably an aliphatic tricyclic hydrocarbon group, in which one or more hydrogen atoms can each independently be replaced by C1-C4 alkyl radicals, C1-C4 alkoxy radicals, fluorine atoms, chlorine atoms, or trifluoromethyl groups, more preferably tricyclodecanylene, even more preferably tricyclo[5.2.1.0 / 2,6]decanylene. Monomer mixture according to claim 1, characterized in that T is a trivalent hydrocarbon group having C3 carbon atoms and is preferably represented by the following formula 5: (Formula 5), ​​wherein the indicated bonds each represent the bonding sites to the oxygen atoms of formula 3. Monomer mixture according to claim 1 or 2, characterized in that A is a divalent hydrocarbon group having C10 carbon atoms and is preferably represented by the following formula 6: where the two indicated bonds each represent the bonding sites to the nitrogen atoms of formula 2. Monomer mixture according to one of claims 1 to 3, characterized in that several base monomers M1, preferably at least two base monomers M1, more preferably more than two base monomers M1, even more preferably more than three base monomers M1, even more preferably more than four base monomers M1 are present in the monomer mixture. Monomer mixture according to one of claims 1 to 4, characterized in that the base monomer M2 is selected from bis(methacryloyloxymethyl)tricyclo[5.2.1.0 / 2,6]decane, Bis(acryloyloxymethyl)tricyclo[5.2.1.0 / 2,6]decane and mixtures thereof, preferably the base monomer M2 is bis(acryloyloxymethyl)tricyclo[5.2.1.0 / 2,6]decane. Monomer mixture according to one of claims 1 to 5, characterized in that the monomer mixture comprises a base monomer M3 which differs from the base monomers M1 of formula 1 and M2 of formula 2, and the base monomer M3 is preferably selected from urethane-based monomers, even more preferably the base monomer M3 is selected from UDMA, UDA, UDA-IPDI, and mixtures thereof. Monomer mixture according to one of claims 1 to 6, characterized in that one or more of the following base monomers are present in the following mass proportions, based on the total mass of the monomer mixture: - base monomer M1 from 2 to 75% by weight, preferably from 5 to 68% by weight, more preferably from 13 to 63% by weight, even more preferably from 15 to 52% by weight; - base monomer M2 from 5 to 96 wt.%, preferably from 12 to 65 wt.%, more preferably from 30 to 63.5 wt.%, even more preferably from 30 to 52 wt.%; - Base monomer M3 from 0 to 75 wt.%, preferably from 0.1 to 65 wt.%, more preferably from 12 to 65 wt.%, even more preferably from 12 to 64 wt.%. Monomer mixture according to one of claims 1 to 7, characterized in that the monomer mixture contains no monomer having a bisphenol A structure, preferably no 2,2-bis[4-(2-hydroxy-3-(meth)acryloxypropoxy)phenyl]propane (BisGMA) and no ethoxylated bisphenol A di(meth)acrylate (BisEMA). Monomer mixture according to one of claims 1 to 8, characterized in that the monomer mixture does not contain any monomer selected from low-molecular-weight and low-viscosity mono- and di(meth)acrylates, any monomer with a viscosity at a temperature of 23°C of less than 0.05 Pas and / or with partial water solubility, and / or any monomer selected from hexanediol diacrylate (HDDA), hexanediol dimethacrylate (HDDMA), triethylene glycol diacrylate (TEGDA), and triethylene glycol dimethacrylate (TEGDMA). Monomer mixture for producing a dental material, comprising: a. at least two or more base monomers M1 represented by the following empirical formula 1: KnUm(OS-PG)o (Formula 1), where PG = a polymerizable group selected from -OOC-CH=CH2 and -OOC-C(CH3)=CH2; S = a spacer group selected from unbranched and branched alkylene with Cl-ClO carbon atoms, which may additionally contain oxygen and / or -OOC- in the carbon chain, is preferably ethylene; 0 = oxygen; U = a group represented by the following formula 2: -CO-NH-A-NH-CO- (Formula 2), where A = a group selected from a divalent aromatic or aliphatic C6-C2O hydrocarbon group, preferably a divalent aliphatic C6-C13 hydrocarbon group, represented by the following formula 6: Formula 6) where the two indicated bonds each represent the represent bonding sites to the nitrogen atoms of formula 2; K = a group represented by the following formula 3 is: T(O) S [((OR) r )O]t (Formula 3) where T = a trivalent hydrocarbon group having C3-C7 carbon atoms, preferably a trivalent hydrocarbon group represented by the following formula 5: (Formula 5), ​​where the three indicated bonds each represent the bonding sites to the oxygen atoms of formula 3, 0 = oxygen, R = each independently selected from an ethylene group, a 1,2-propylene group, a 1,3-propylene group and a mixture thereof, preferably a 1,2-propylene group, r = each independently 1-12, preferably 1-9, even more preferably 1-6, s = 0 or 1, preferably 0, t = 2 or 3, preferably 3, where the condition must be met that s+t = 3; n = 1-9, preferably 1-7, even more preferably 1-5; where the conditions must be met that m = 2n+1 and o = n+2; b. optionally at least one base monomer M2 of the following formula 4: PG'-S'-A'—S'—PG' (Formula 4), where PG' = a polymerizable group selected from OOC-CH=CH2 and -OOC-C(CH3)=CH2; S' = a spacer group selected from unbranched and branched alkylene with Cl-ClO carbon atoms, which may additionally contain oxygen and / or -OOC- in the carbon chain, is preferably methylene, or S' is omitted; A' = an aliphatic polycyclic group, preferably an aliphatic tricyclic hydrocarbon group, in which one or more hydrogen atoms can each independently be replaced by Cl-C4-alkyl radicals, Cl-C4-alkoxy radicals, fluorine atoms, chlorine atoms or trifluoromethyl groups, more preferably tricyclodecanylene, even more preferably tricyclo [5.2.1.0 2 ' 6]decanylene. Use of the monomer mixture according to any one of claims 1 to 10 for producing a polymerizable dental material, preferably a dental composite, core build-up, root canal filling, filling, lining, luting, crown, bridge, restoration and / or prosthesis material. Polymerizable dental material comprising: a) a monomer mixture according to any one of claims 1 to 10; b) optionally at least one initiator or initiator system for polymerization; c) optional fillers; d) optional dental additives.

13. Dental material according to claim 12, characterized in that one or more of the following components are contained in the dental material in the following mass proportions, based on the total mass of the dental material: a) the monomer mixture from 5 to 99 wt.%, preferably from 10 to 95 wt.%, more preferably from 15 to 85 wt.%; b) the at least one initiator or initiator system for the polymerization from 0 to 5 wt.%, preferably from 0.01 to 5 wt.%; c) the fillers from 0 to 95 wt.%, preferably from 1 to 95 wt.%, more preferably from 5 to 90 wt.%, even more preferably from 15 to 85 wt.%; d) the dental additives from 0 to 5 wt.%, preferably from 0.001 to 5 wt.%.

14. Dental material according to one of claims 12 to 13 for use in a therapeutic procedure as a dental composite, filling, underfilling, luting, core build-up, root canal filling, crown, bridge, restoration and / or prosthesis material.

15. Cured dental material made from a polymerizable dental material according to one of claims 12 to 13.

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