Dental Composition

Abstract

The present invention relates to a dental composition comprising at least one polymerizable monomer having at least one ethylenically unsaturated group, a photosensitizer having an absorption maximum in the range of 400 nm to 800 nm, and a radical initiator system comprising at least one CH-acidic compound as a coinitiator.

Description

[Technical field]

[0001] The present invention relates to a dental composition comprising at least one polymerizable monomer having at least one ethylenically unsaturated group, a photosensitizer having an absorption maximum in the range of 400 nm to 800 nm, and a radical initiator system comprising at least one CH-acidic compound as a coinitiator. [Background technology]

[0002] Dental restorations typically include light-curable dental compositions containing free radically polymerizable resins. Light-curing of dental compositions involves a photoinitiator system that generates free radicals upon exposure to visible light. Traditionally, photosensitizers such as camphorquinone (CQ), optionally in combination with a tertiary aromatic amine, are often used as the photoinitiator system.

[0003] However, the presence of amines in (meth)acrylate-containing compositions can cause yellowing of the resulting photocured composition. Another drawback of tertiary aromatic amines is their tendency to discolor and their sensitivity to strong acidic media. In addition, tertiary aromatic amines react with oxygen radicals. Thus, while on the one hand their use has the benefit of avoiding sticky surfaces, on the other hand more aromatic amines are needed for initiation than the stoichiometric requirement for the respective photosensitizer, such as CQ. Tertiary aromatic amines for use as co-initiators in dental compositions can leach out of the cured composition, which can cause toxicological concerns. In particular, the toxicological concerns about tertiary aromatic amines necessitate the development of new co-initiators for photosensitizers, such as CQ, in dental materials.

[0004] Objective of the invention In view of the prior art, it was therefore an object of the present invention to provide a novel dental composition comprising an initiator system which does not exhibit the aforementioned drawbacks of the known prior art dental compositions.

[0005] In particular, it was an object of the present invention to provide dental compositions that include an initiator system that is at least substantially free, and preferably completely free, of amines, particularly tertiary amines, and more particularly tertiary aromatic amines.

[0006] Therefore, what is needed is a method to provide new coinitiators for common photosensitizers such as camphorquinone in dental compositions, where the coinitiators do not contain amines.

[0007] It is further an object of the present invention to provide dental compositions comprising a radical initiator system containing a combination of a photosensitizer and at least one coinitiator that is a CH-acidic compound, which can reduce, and ideally avoid or eliminate, the leaching issues and toxicological concerns of commonly used tertiary aromatic amine based coinitiators, while simultaneously improving the required biocompatibility. Summary of the Invention

[0008] These objects, and also further objects not expressly stated but which can be immediately derived or discerned from the relationships discussed herein as a preamble, are achieved by a dental composition having all the features of claim 1. Appropriate modifications of the dental composition are protected in the dependent claims 2 to 15.

[0009] The present invention therefore comprises: a) at least one polymerizable monomer having at least one ethylenically unsaturated group; 1. A dental composition comprising: b) a radical initiator system, i. a photosensitizer having an absorption maximum in the range of 400 nm to 800 nm; ii. at least one CH-acidic compound as a coinitiator; A radical initiator system comprising The dental composition further comprises:

[0010] It is therefore possible to provide novel dental compositions comprising initiator systems which, in an unpredictable manner, do not exhibit the aforementioned drawbacks of known prior art dental compositions.

[0011] Specifically, the present invention provides dental compositions that include a radical initiator system that is at least substantially free, and preferably completely free, of amines, particularly tertiary amines, and more particularly tertiary aromatic amines.

[0012] The present invention thereby provides novel, amine-free coinitiators for common photosensitizers such as camphorquinone in dental compositions.

[0013] Further provided are dental compositions comprising a radical initiator system containing a combination of a photosensitizer and at least one coinitiator that is a CH-acidic compound, such inventive dental compositions that can reduce, and ideally avoid or eliminate, the leaching issues and toxicological concerns of commonly used tertiary aromatic amine based coinitiators while simultaneously improving the required biocompatibility.

[0014] The dental composition comprising at least one CH-acidic compound as co-initiator provides improved polymerization efficiency, including good conversion, without causing aromatic amine leaching problems.The co-initiator of the present invention, being a CH-acidic compound, is stable in strong acidic medium, making it suitable for dental applications such as adhesives and self-etching formulations.When incorporated into such dental composition, the co-initiator of the present invention has low discoloration tendency while simultaneously showing good storage stability.

[0015] At least one coinitiator that is a CH-acidic compound acts by initiating the polymerization of one or more polymerizable monomers having at least one ethylenically unsaturated group. When incorporated into such dental compositions, the coinitiators of the present invention provide biocompatibility with reduced component release.

[0016] For a more complete understanding of the present invention, reference is now made to the following detailed description taken in conjunction with the accompanying drawings, in which: [Brief description of the drawings]

[0017] [Figure 1] Photopolymerization profiles of methacrylate functional group (TPH3) in the presence of (1) CQ (0.5% wt) or (2) CQ / lactone (HD-8) (0.5 / 3% w / w) or (4) CQ / DMABE (0.5 / 1% w / w) or (3) CQ / lactone (HD-8) / Speedcure 938 (0.5 / 3 / 1% w / w) under exposure to Smartlite Focus (300 mW / cm2) with a sample thickness of 1.4 mm and in air. [Diagram 2] Photopolymerization profiles of C=C double bonds (PrimeBond Active) in the presence of (1) CQ (1.5% w / w) or (2) CQ / Speedcure 938 (1.5 / 0.75% w / w) or (3) CQ / acetylbutyrolactone (HD-8) / iodonium sulfonate (1.5 / 1.2 / 0.75% w / w) or (4) CQ / acetylbutyrolactone (HD-8) / Speedcure 938 (1.5 / 1.2 / 0.75% w / w) or under exposure to a SmartLite Focus (300 mW / cm2), sample thickness 17 μm, and air. [Diagram 3]Photopolymerization profiles of methacrylate functional groups (TPH3) in the presence of camphorquinone as photoinitiator (air, thickness = 1.4 mm, SmartLite Focus 300 mW / cm2) are shown for: (1) CQ / HD-1 / SC938 (0.5 / 3 / 1% w / w), (2) CQ / HD-2 / SC938 (0.5 / 3 / 1% w / w), (3) CQ / HD-3 / SC938 (0.5 / 3 / 1% w / w), (4) CQ / HD-4 / SC938 (0.5 / 3 / 1% w / w), (5) CQ / HD-5 / SC938 (0.5 / 3 / 1% w / w). 8 (0.5 / 3 / 1% w / w), (6) CQ / HD-6 / SC938 (0.5 / 3 / 1% w / w), (7) CQ / HD-7 / SC938 (0.5 / 3 / 1% w / w), (8) CQ / HD-8 / SC938 (0.5 / 3 / 1% w / w), (9) CQ / HD-10 / SC938 (0.5 / 3 / 1% w / w), (10) CQ / DMABE (0.5 / 0.5% w / w), (11) CQ (0.5% w / w). Irradiation begins at t = 5 seconds. [Figure 4] Photopolymerization profiles of methacrylate functional group (TPH3) in the presence of camphorquinone as photoinitiator (air, thickness = 1.4 mm, SmartLite Focus 300 mW / cm2): (1) CQ / TPH3 (0.5 / 100% w / w), (2) CQ / HD-9 / TPH3 (0.5 / 5 / 95% w / w), (3) CQ / HD-9 / SC938 / TPH3 (0.5 / 5 / 1 / 100% w / w), (4) CQ / DMABE / TPH3 (0.5 / 0.6 / 100% w / w), (5) CQ / DMABE / HD-9 / TPH3 (0.5 / 0.6 / 5 / 95% w / w). Irradiation starts at t = 5 s. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The term "alkyl," unless otherwise specified, refers to a monoradical branched or unbranched saturated hydrocarbon chain having 1 to 18 carbon atoms. This term can be exemplified by groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, n-decyl, dodecyl, and tetradecyl.

[0019] The term "alkoxy group", unless otherwise specified, refers to a monoradical branched or unbranched saturated hydrocarbon chain having 1 to 18 carbon atoms, at least one carbon atom of such alkoxy group being substituted with an oxygen atom. Such alkoxy group is bonded to a carbon atom of the compound by said at least one oxygen atom. This term can be exemplified by groups such as methoxy and ethoxy. That is, the term "alkoxy group" is defined in the context of the present invention as understood by a chemist based on common chemical knowledge.

[0020] The term "alkylene", unless otherwise specified, refers to a linear saturated divalent hydrocarbon radical having one to four carbon atoms or a branched saturated divalent hydrocarbon radical having three to four carbon atoms, such as methylene, ethylene, 2,2-dimethylethylene, propylene, 2-methylpropylene, and butylene, preferably methylene, ethylene, or propylene.

[0021] The term "aryl" refers to a C6-C10 membered aromatic, heterocyclic, fused aromatic, fused heterocyclic, biaromatic, or biheterocyclic ring system. Broadly defined, "aryl" as used herein includes 5-, 6-, 7-, 8-, 9-, and 10-membered monocyclic aromatic groups that may contain 0-4 heteroatoms, such as, for example, benzene, pyrrole, furan, thiophene, imidazole, oxazole, thiazole, triazole, pyrazole, pyridine, pyrazine, pyridazine, and pyrimidine. "Aryl" groups having heteroatoms in the ring structure may also be referred to as "heteroaryl" or "heterocyclic" or "heteroaromatic". The aromatic ring may be substituted at one or more ring positions with one or more substituents including, but not limited to, halogen, azide, alkyl, aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxyl, alkoxyl, amino (or quaternized amino), nitro, sulfhydryl, imino, amide, phosphonic acid, phosphate, carbonyl, carboxyl, silyl, ether, alkylthio, sulfonyl, sulfonamide, ketone, aldehyde, ester, heterocyclyl, aromatic or heteroaromatic moiety, --CF3, --CN, and combinations thereof.

[0022] The term "cycloalkyl" refers to a monocyclic or polycyclic cycloalkyl radical. Examples of monocyclic acycloalkyls include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. Examples of polycyclic cycloalkyl radicals include, for example, adamantyl, norbornyl, decalinyl, 7,7-dimethyl-bicyclo[2.2.1]heptanyl, and tricyclo[5.2.1.02,6]decyl.

[0023] The term "(meth)acrylate," in the context of the present disclosure, is intended to refer to both the acrylate and the corresponding methacrylate.

[0024] The term "(meth)acrylamide," in the context of this disclosure, is intended to include acrylamide and methacrylamide.

[0025] The term "polymerizable monomer" in the context of this disclosure means any monomer capable of radical polymerization. The polymerizable monomer contains at least one ethylenically unsaturated group. The at least one ethylenically unsaturated group includes vinyl, allyl, acrylic, methacrylic, and styryl.

[0026] The terms "polymerizable monomer having at least one ethylenically unsaturated group" and "ethylenically unsaturated monomer" may be used interchangeably.

[0027] The term "radical initiator system", in the context of this disclosure, means any system comprising a sensitizer and at least one coinitiator that upon activation by heat or light and / or environmental redox conditions forms free radicals, thereby initiating the polymerization of polymerizable monomers.

[0028] The term "co-initiator", in the context of the present disclosure, means a compound that does not essentially absorb upon exposure to UV radiation or visible light, but forms free radicals together with the sensitizer used in accordance with the present disclosure.

[0029] The term "sensitizer", in the context of this disclosure, refers to a compound that is capable of absorbing radiation in the wavelength range of 400-800 nm upon exposure, but is not capable of forming free radicals alone, i.e., without the addition of a coinitiator. Sensitizers used in this disclosure must be capable of interacting with the coinitiators used in this disclosure.

[0030] The present disclosure relates to a dental composition selected from a dental adhesive, a dental composite, a root canal filling composition, a dental sealant, and a dental cement.

[0031] The dental compositions of the present disclosure include one or more polymerizable monomers having at least one ethylenically unsaturated group.

[0032] The polymerizable monomer may be an acrylate, a methacrylate, an ethylenically unsaturated compound, a carboxyl group-containing unsaturated monomer, a C2-8 hydroxyl alkyl ester of (meth)acrylic acid, a C1-24 alkyl ester or cycloalkyl ester of (meth)acrylic acid, a C2-18 alkoxy alkyl ester of (meth)acrylic acid, an olefin or diene compound, a monoester / diester, a monoether, an adduct, a vinyl monomer, a styryl monomer, a TPH resin, an SDR resin, a PBA resin, and / or a BPA-free resin.

[0033] Radical Initiator System The dental composition of the present disclosure includes a radical initiator system. The radical initiator system can include a photoinitiator. The suitable photoinitiator can be in the form of a two-component or three-component system. The two-component system can include a photosensitizer and a CH-acidic compound as a coinitiator. The three-component system can further include an additional iodonium, sulfonium, or phosphonium salt.

[0034] In the context of the present invention, the expression "CH-acidic compounds" refers to "α-CH-acidic compounds". This last definition is clearly understandable (see also general textbooks of organic chemistry such as "Organikum").

[0035] Such CH-acidic compounds may contain additional functionality, such as at least one ethylenically unsaturated group, that allows them to participate in the polymerization process as at least one polymerizable monomer.

[0036] This could be an additional advantage of using such specific coinitiators, which are not only suitable to replace toxic amine-based coinitiators but also present the possibility to be incorporated into the growing polymer chain.

[0037] In one embodiment, the at least one CH-acidic compound has the following formula (I): [ka] (In the formula, R7, R 10 =C1-C8 alkoxy, C1-C8 alkyl, hydroxy, thiol, amine, or -OCH2CH2OC(O)C(CH3)CH2 moiety, preferably a methoxy, ethoxy, hydroxy, amine, methyl, or -OCH2CH2OC(O)C(CH3)CH2 moiety; R8, R9 = hydrogen, C1-C8 alkyl, or acetyl moiety, preferably hydrogen, methyl, or acetyl moiety, provided that at least R8 or R9 is a hydrogen moiety. It is a compound according to the above.

[0038] In a preferred embodiment thereof, the at least one CH-acidic compound has the following formulae (Ia) and (Ib): [ka] where R, R=hydrogen, C1-C8 alkyl, or acetyl moiety, preferably hydrogen, methyl, or acetyl moiety, with the proviso that at least R or R is a hydrogen moiety; R 11 , R 12 = hydrogen, C1-C8 alkyl, or a -CH2CH2OC(O)C(CH3)CH2 moiety, preferably hydrogen, methyl, ethyl, or a -CH2CH2OC(O)C(CH3)CH2 moiety) [ka] (In the formula, R7 = C1-C8 alkoxy, C1-C8 alkyl, hydroxy, thiol, amine, or -OCH2CH2OC(O)C(CH3)CH2 moiety, preferably methoxy, ethoxy, hydroxy, amine, methyl, or -OCH2CH2OC(O)C(CH3)CH2 moiety; R8, R9=hydrogen, C1-C8 alkyl, or acetyl moiety, preferably hydrogen, methyl, or acetyl moiety, with the proviso that at least R8 or R9 is a hydrogen moiety; R12 = hydrogen, C1-C8 alkyl, or a -CH2CH2OC(O)C(CH3)CH2 moiety, preferably hydrogen, methyl, ethyl, or a -CH2CH2OC(O)C(CH3)CH2 moiety) is a compound according to one of the following: Preferably, the at least one CH-acidic compound is ethyl 2-methylacetoacetate (HD-3), ethyl diacetoacetate (HD-5), or 2-(methacryloyloxy)ethyl acetoacetate (HD-10).

[0039] In an alternative embodiment, the at least one CH-acidic compound has the following formula (II): [ka] (In the formula, R 13 = hydrogen, C1-C8 alkyl, carboxylic acid, acetyl, or -CH2OC(O)C(CH3)CH2 moiety, where the C1-C8 alkyl moiety may be substituted with at least a nitrile group, a hydroxy group, or a carboxylic acid group; Preferably, it is a methyl, -CHOH, -COOH, -CHCOOH, -CHCN, acetyl, or -CHOC(O)C(CH)CH moiety. It is a compound according to the above.

[0040] In a preferred embodiment thereof, the at least one CH-acidic compound has the following formulae (IIa) and (IIb): [ka] (In the formula, R 14 = hydrogen, C1-C8 alkyl, or a hydroxy moiety, preferably a methyl or hydroxy moiety) [ka] (In the formula, R 15= hydrogen, hydroxy, carboxylic acid, nitrile, or -OC(O)C(CH3)CH2 moiety) It is a compound related to one of the above.

[0041] In another alternative embodiment, the at least one CH-acidic compound has the following formula (III): [ka] (In the formula, R 16 = Hydrogen, C1-C 18 Alkyl, or C1-C 18 a cycloalkyl moiety, in which at least one carbon atom in the C1-C8 alkyl or cycloalkyl moiety may be substituted with nitrogen, and the C1-C8 alkyl or cycloalkyl moiety may be substituted with at least a double-bonded oxygen atom, an aromatic, and / or a heteroaromatic group; The compound according to the formula: Preferably, the at least one CH-acidic compound is N-(diphenylmethylene)glycine ethyl ester (HD-1), ethyl 2-oxocyclopentanecarboxylate (HD-2), or ethyl 2-ethyl-2-methylacetoacetate (HD-4).

[0042] In another alternative embodiment, the at least one CH-acidic compound has the following formula (IV): [ka] (In the formula, R 17 , R 18 = hydrogen or a C1-C8 alkyl moiety) The compound according to the formula: Preferably, the at least one CH-acidic compound is dimethyl 1,4-cyclohexanedione-2,5-dicarboxylate (HD-6).

[0043] In another alternative embodiment, the at least one CH-acidic compound has the following formula (V): [ka] (In the formula, R 19 , R 20 = hydrogen or a C1-C8 alkyl moiety) The compound according to the formula: Preferably, at least one CH-acidic compound is dehydroacetic acid (HD-7).

[0044] In another alternative embodiment, the at least one CH-acidic compound has the following formula (VI): [ka] (In the formula, R1, R2, R3, R4, R5, R6 = hydrogen, C1-C8 alkyl, carboxylic acid, acetyl, or -OC(O)CHCH2 moiety, provided that at least R1, R2, R5, or R6, preferably R5 or R6, is a hydrogen moiety. The compound according to the formula: Preferably, the at least one CH-acidic compound has the following formula (VIa): [ka] (In the formula, R3, R4, R6 = hydrogen, C1-C8 alkyl, carboxylic acid, acetyl, or -OC(O)CHCH2 moiety The compound according to the formula: More preferably, the at least one CH-acidic compound is α-acetylbutyrolactone (HD-8), or (R)-α-acryloyloxy-β,β-dimethyl-γ-butyrolactone (HD-9).

[0045] In formula (VIa), R1, R2, and R5 are each hydrogen moieties.

[0046] In conclusion, according to one embodiment of the present invention, the at least one CH-acidic compound is a compound according to one of formulae (I), (Ia), (Ib), (II), (IIa), (IIb), (III), (IV), (V), (VI) and (VIa) as defined above.

[0047] When more than one CH-acidic compound is included by the radical initiator system of the present invention, all included CH-acidic compounds can be compounds according to the same formula (I), (Ia), (Ib), (II), (IIa), (IIb), (III), (IV), (V), (VI), or (VIa).

[0048] Alternatively, when two or more CH-acidic compounds are included by the radical initiator system of the present invention, each of the included CH-acidic compounds can be a compound according to formula (I), (Ia), (Ib), (II), (IIa), (IIb), (III), (IV), (V), (VI), or (VIa), but in no case are two CH-acidic compounds according to the same formula (I), (Ia), (Ib), (II), (IIa), (IIb), (III), (IV), (V), (VI), or (VIa).

[0049] As a further alternative, when two or more CH-acidic compounds are included by the radical initiator system of the present invention, at least two of the included CH-acidic compounds can be compounds according to the same Formula (I), (Ia), (Ib), (II), (IIa), (IIb), (III), (IV), (V), (VI), or (VIa).

[0050] In one embodiment, the dental composition further comprises an additive selected from an iodonium salt, a phosphonium salt, and a sulfonium salt, preferably, the additive is an iodonium salt.

[0051] In one preferred embodiment thereof, the additive is present in an amount of 0.01 to 5 weight percent based on the total weight of the dental composition.

[0052] Such iodonium compounds have the following formula (C): R 21 -I + -R 22 A - Formula (C) (In the formula, R 21 and R 22 are independent of each other and represent an organic moiety, A - is an anion) may include.

[0053] In embodiments, the iodonium compounds include diphenyliodonium (DPI) hexafluorophosphate, di(4-methylphenyl)iodonium (Me2-DPI) hexafluorophosphate, di-(4-t-butylphenyl)-iodonium hexafluorophosphate, diaryliodonium hexafluoroantimonate, (4-methylphenyl)[4-(2-methylpropyl)phenyl]iodonium hexafluoroantimonate, (4-methylphenyl)[4-(2-methylpropyl)phenyl]iodonium hexafluorophosphate (Irgacure® 250, BASF Chemicals, Inc.), commercially available from SE), (4-methylphenyl)[4-(2-methylpropyl)phenyl]iodonium tetrafluoroborate, 4-octyloxyphenylphenyliodonium hexafluoroantimonate, 4-(2-hydroxytetradecyloxyphenyl)phenyliodonium hexafluoroantimonate, and 4-isopropyl-4'-methyldiphenyliodonium borate.

[0054] According to further embodiments, the iodonium compound is di-(4-t-butylphenyl)-iodonium hexafluorophosphate, di(4-methylphenyl)iodonium (Me2-DPI) hexafluorophosphate, or bis(4-tert-butylphenyl)iodonium p-toluenesulfonate.

[0055] According to a further embodiment, the photoinitiator has the following formula (D): R 23 R 24 R 25 S + A - Formula (D) (In the formula, R 23 , R 24 , and R 25 are independent of each other and represent an organic moiety or R 23 , R 24 , and R 25 Any two of the following may form a ring structure together with the sulfur atom to which they are attached: A - is an anion) The sulfonium compounds may include those of the formula:

[0056] The triarylsulfonium salt is as follows: [ka] S-(phenyl)thianthrenium hexafluorophosphate of the formula:

[0057] According to a further embodiment, the photoinitiator has the following formula (E): R 26 R 27 R 28 R 29 P + A - Formula (E) (In the formula, R 26 , R 27 , R 28 , and R 29 are independent of each other and represent an organic moiety, A - is an anion) The phosphonium compounds may include those of the formula:

[0058] The phosphonium salt of formula (E) can be a tetraalkylphosphonium salt, a tetrakis-(hydroxymethyl)-phosphonium (THP) salt, or a tetrakis-(hydroxymethyl)-phosphonium hydroxide (THPOH) salt, where the anion of the tetraalkylphosphonium salt is selected from the group consisting of formate, acetate, phosphate, sulfate, fluoride, chloride, bromide, and iodide.

[0059] Other suitable photoinitiators for polymerizing free radical photopolymerizable compositions can include the class of phosphine oxides, typically having a functional wavelength range of about 380 nm to about 1200 nm. Additional suitable phosphine oxide free radical initiators having a functional wavelength range of about 380 nm to about 450 nm are the acyl and bisacyl phosphine oxides.

[0060] In one embodiment, the photosensitizer is a 1,2-diketone compound, and preferably, the photosensitizer is present in an amount of 0.01 to 5 weight percent based on the total weight of the dental composition.

[0061] The alpha-diketone sensitizer compound may be selected from camphorquinone, 1,2-diphenylethane-1,2-dione (benzyl), 1,2-cyclohexanedione, 2,3-pentanedione, 2,3-hexanedione, 3,4-hexanedione, 2,3-heptanedione, 3,4-heptanedione, glyoxal, biacetyl, 3,3,6,6-tetramethylcyclohexanedione, 3,3,7,7-tetramethyl-1,2-cycloheptanedione, 3,3,8,8-tetramethyl-1,2-cyclooctanedione, 3,3,18,18-tetramethyl-1,2-cyclooctadecanedione, dipivaloyl, furyl, hydroxybenzyl, 2,3-butanedione, 2,3-octanedione, 4,5-octanedione, and 1-phenyl-1,2-propanedione.

[0062] In one embodiment, the radical initiator system is present in an amount from 0.1 to 10 weight percent based on the total weight of the dental composition.

[0063] In one embodiment, the at least one CH-acidic compound is present in an amount of 0.01 to 5 weight percent based on the total weight of the dental composition.

[0064] In one embodiment, the dental composition comprises a radical initiator system that is at least substantially free, and preferably completely free, of amines, particularly tertiary amines, and more particularly tertiary aromatic amines.

[0065] The present invention therefore addresses the problem of providing inventive dental compositions that include an improved initiator system.

[0066] The following non-limiting examples are provided to illustrate embodiments of the present invention and to facilitate an understanding of the invention, but are not intended to limit the scope of the invention, which is defined by the claims appended hereto.

[0067] The compounds used in the present invention and comparative experiments are listed below: [ka] JPEG0007645872000014.jpg100162

[0068] As used herein, "SC938" refers to "speedcure 938."

[0069] Example 1: Use of (R)-α-acyloyl-γ-butyrolactone (HD-8) as a coinitiator for the polymerization of TPH3 resin (a methacrylate resin) In the presence of (1) CQ (0.5% wt), or (2) CQ / lactone (HD-8) (0.5 / 3% w / w), or (4) CQ / DMABE (0.5 / 1% w / w), or (3) CQ / lactone (HD-8) / Speedcure 938 (0.5 / 3 / 1% w / w), the cells were incubated at 37°C for 1 h at 4°C for 1 h at 100°C for 2 h at 15°C for 1 h at 1 ... 2Photopolymerization profile of methacrylate functional group (TPH3) under exposure to 1.4 mm sample thickness in air (shown in Figure 1). Good reactivity of CQ / lactone (HD-8) / Speedcure 938 in TPH3 was observed, which is similar to CQ / DMABE but is an amine-free system.

[0070] Here, it is clearly demonstrated that the use of CH-acidic coinitiators in combination with CQ works better than CQ alone.Furthermore, it is shown that the CQ with CH-acidic coinitiators and iodonium compounds in three-component system works much better than the two-component system of CQ with each identical CH-acidic coinitiator.The comparative example of CQ with tertiary amine DMABE shows similar performance to the three-component example of the present invention.This proves that the present invention has succeeded in providing a suitable dental composition with an initiator system that can perform the same as the initiator system of CQ combined with environmentally toxic, commonly used tertiary amine as coinitiator.

[0071] Example 2: Use of (R)-α-acyloyl-γ-butyrolactone (HD-8) as a coinitiator for the polymerization of Prime&bond Active resin (methacrylate resin) In the presence of (1) CQ (1.5% w / w) or (2) CQ / Speedcure 938 (1.5 / 0.75% w / w) or (3) CQ / acetylbutyrolactone (HD-8) / bis(4-tert-butylphenyl)iodonium p-toluenesulfonate (1.5 / 1.2 / 0.75% w / w) or (4) CQ / acetylbutyrolactone (HD-8) / Speedcure 938 (1.5 / 1.2 / 0.75% w / w), or in the presence of a SmartLite Focus (300 mW / cm 2 Photopolymerization profile of a C=C double bond (PrimeBond Active) under exposure to 1000 nm UV radiation with a sample thickness of 17 μm and in air (Figure 2).

[0072] Good reactivity was observed with CQ / lactone (HD-8) / Speedcure 938 and CQ / lactone / iodonium sulfonate in PBA, which are amine-free systems. A slightly sticky polymer was obtained.

[0073] Here, it is clearly demonstrated that the performance of the three-component initiator system of the present invention, CQ combined with CH-acidic compounds and iodonium compounds, is better than CQ alone or the combination of CQ and iodonium ions. This proves that the favorable performance shown in Figure 1 is due to the CH-acidic compounds. The combination of iodonium compounds and CQ is not superior and is not a substitute. However, when used additionally with CQ and CH-acidic compounds, the use of such iodonium compounds has been shown to be meaningful for further improving the performance of the two-component system of CQ and the respective CH-acidic compounds.

[0074] Example 3. Systematic review of multiple CH-acidic compounds in combination with CQ, including comparisons with CQ alone and with CQ in combination with a tertiary amine (DMABE) In the presence of camphorquinone as a photoinitiator (air, thickness = 1.4 mm, SmartLite Focus 300 mW / cm 2 Photopolymerization profile of methacrylate functional group (TPH3) in: (1) CQ / HD-1 / SC938 (0.5 / 3 / 1% w / w), (2) CQ / HD-2 / SC938 (0.5 / 3 / 1% w / w), (3) CQ / HD-3 / SC938 (0.5 / 3 / 1% w / w), (4) CQ / HD-4 / SC938 (0.5 / 3 / 1% w / w), (5) CQ / HD-5 / SC938 (0.5 / (3 / 1% w / w), (6) CQ / HD-6 / SC938 (0.5 / 3 / 1% w / w), (7) CQ / HD-7 / SC938 (0.5 / 3 / 1% w / w), (8) CQ / HD-8 / SC938 (0.5 / 3 / 1% w / w), (9) CQ / HD-10 / SC938 (0.5 / 3 / 1% w / w), (10) CQ / DMABE (0.5 / 0.5% w / w), (11) CQ (0.5% w / w). Irradiation begins at t = 5 seconds (as shown in Figure 3).

[0075] The novel CH-acidic compounds (HD-1 to HD-10) were used in combination with camphorquinone (CQ) as efficient co-initiators for the free radical polymerization of methacrylates under air and exposure to blue dental LEDs (SmartLite Focus-Dentsply Sirona). Notably, they can be used in combination with CQ and iodonium salts, and these amine-free systems show superior polymerization performance compared to the current comparative reference systems CQ / DMABE and CQ alone. For example, the polymerization of TPH3 resin (a methacrylate resin) in the presence of CQ / CH-acidic compounds / SC938, using nine different CH-acidic compounds as co-initiators in each of the investigated photoinitiator systems, is shown in Figure 3.

[0076] Here, it is again demonstrated that the performance of the ternary initiator system of the present invention of CQ in combination with a CH-acidic compound and an iodonium compound is better than CQ alone or at least similar to the combination of CQ with a commonly used tertiary amine (DMABE) as a coinitiator.

[0077] Example 4. Use of (R)-α-acryloyloxy-β,β-dimethyl-γ-butyrolactone (HD-9) as a coinitiator (R)-α-Acryloyloxy-β,β-dimethyl-γ-butyrolactone (HD-9) was proposed in combination with camphorquinone as a novel coinitiator. For example, the polymerization of TPH3 resin in the presence of CQ / HD-9, CQ / HD-9 / SC938, and CQ / DMABE / HD-9 as photoinitiator systems is shown in Figure 4. The amine-free system CQ / HD-9 / SC938 shows excellent polymerization performance similar to the reference comparison system CQ / DMABE.

[0078] In the presence of camphorquinone as a photoinitiator (air, thickness = 1.4 mm, SmartLite Focus 300 mW / cm 2Photopolymerization profile of methacrylate functional group (TPH3) in: (1) CQ / TPH3 (0.5 / 100% w / w), (2) CQ / HD-9 / TPH3 (0.5 / 5 / 95% w / w), (3) CQ / HD-9 / SC938 / TPH3 (0.5 / 5 / 1 / 100% w / w), (4) CQ / DMABE / TPH3 (0.5 / 0.6 / 100% w / w). Irradiation starts at t = 5 s (shown in Figure 4).

[0079] While the principles of the invention have been explained in relation to specific embodiments, it is to be understood that various modifications thereof will become apparent to those skilled in the art upon reading the specification. It is therefore to be understood that the invention disclosed herein is intended to cover such modifications as fall within the scope of the appended claims. The scope of the invention is limited only by the scope of the appended claims.

Claims

1. a) at least one polymerizable monomer having at least one ethylenically unsaturated group; 1. A dental composition comprising: b) a radical initiator system, i. a photosensitizer having an absorption maximum in the range of 400 nm to 800 nm; ii. at least one CH-acidic compound as a coinitiator; A radical initiator system comprising The composition further comprises The at least one CH-acidic compound has the following formula (I): 【Chemistry 1】 (In the formula, R 7 , R 10 = methoxy, ethoxy, hydroxy, amine, methyl, or -OCH 2 CH 2 OC(O)C(CH 3 )CH 2 ; R 8 , R 9 = hydrogen, methyl, or acetyl, with the proviso that at least R 8 or R 9 is hydrogen. The compound according to the present invention is A dental composition comprising an iodonium salt additive.

2. The at least one CH-acidic compound has the following formulas (Ia) and (Ib): 【Chemistry 2】 (In the formula, R ８ , R ９ = hydrogen, methyl, or acetyl, provided that at least R ８ Or R ９ is hydrogen, R １１ , R １２ = hydrogen, methyl, ethyl, or -CH ２ CH ２ O C (O) C (CH ３ ) CH ２ (It is) 【Chemistry 3】 (In the formula, R ７ =Methoxy, ethoxy, hydroxy, amine, methyl, or -OCH ２ CH ２ O C (O) C (CH ３ ) CH ２ and R ８ , R ９ = hydrogen, methyl, or acetyl, provided that at least R ８ Or R ９ is hydrogen, R １２ = hydrogen, methyl, ethyl, or -CH ２ CH ２ O C (O) C (CH ３ ) CH ２ (It is) is a compound according to one of the following: The at least one CH-acidic compound is ethyl 2-methylacetoacetate (HD-3), ethyl diacetoacetate (HD-5), or 2-(methacryloyloxy)ethyl acetoacetate (HD-10). The dental composition according to claim 1 .

3. The dental composition of claim 1, characterized in that the additive is present in an amount of 0.01 to 5 weight percent based on the total weight of the dental composition.

4. A dental composition described in any one of claims 1 to 3, characterized in that the photosensitizer is a 1,2-diketone compound and is present in an amount of 0.01 to 5 weight percent based on the total weight of the dental composition.

5. A dental composition described in any one of claims 1 to 4, characterized in that the radical initiator system is present in an amount of 0.1 to 10 weight percent based on the total weight of the dental composition.

6. 6. The dental composition of claim 1, wherein the at least one CH-acidic compound is present in an amount of 0.01 to 5 percent by weight, based on the total weight of the dental composition.

7. The dental composition according to any one of claims 1 to 6, characterized in that the dental composition comprises a radical initiator system that does not contain a tertiary aromatic amine.

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