Dental hardening composition

Abstract

The present invention relates to a dental hardenable composition. The invention is characterized in that the composition comprises a core-shell impact modifier and 0.1-10 wt % of a binder based on a long-chain monofunctional (meth)acrylic ester, where the ester group has a carbon chain with at least 3 carbon atoms. The invention also relates to the use of the composition as a dental material or dental auxiliary material, a dental product comprising the composition, and a method for producing the dental product.

Description

[Technical field]

[0001] The present invention relates to a dental hardenable composition comprising a core-shell impact modifier and 0.1-10% by weight of a binder based on a longer chain monofunctional (meth)acrylate, the ester group of which has a carbon chain with at least 3 carbon atoms, to the use of said composition as a dental material or dental auxiliary, to dental products made from said composition and to a process for making said dental products. [Background technology]

[0002] For example, hardenable compositions, such as those employed in Additive Manufacturing, are known to those skilled in the art and have been introduced into the dental field, allowing dental products, such as dental restorations, to be manufactured with great precision and individual fit.

[0003] EP 3564282 A1 describes a curable composition for use in high temperature lithography based photopolymerization processes, which contains certain oligomeric dimethyl acrylates as glass transition modifiers. Summary of the Invention [Problem to be solved by the invention]

[0004] US Patent Application Publication No. 2021 / 0017302 discloses a resin composition comprising one or more photoinitiators, one or more hard crosslinkers, where the one or more hard crosslinkers have at least two reactive groups and are present at 20-75 wt% (based on the total weight of the composition), and one or more soft crosslinkers, where the one or more soft crosslinkers have at least two reactive groups and are present at 2-70 wt% (based on the total weight of the composition), and / or the one or more reactive diluents have only one reactive group and are present at 2-70 wt% (based on the total weight of the composition).

[0005] WO 2014 / 078537 relates to a composition for making a three-dimensional dental product, the three-dimensional dental product comprising at least 1% methyl methacrylate and / or ethyl methacrylate, 5-10% silicone acrylic rubber impact modifier, where the core is silicone and the shell is PMMA acrylic, which does not dissolve at room temperature or at elevated temperatures and swells to form a colloid, 1-90% of at least one mono- or polyfunctional (meth)acrylate, 0-60% of at least one inorganic filler, 0-60% of at least one organic filler, 0-10% of pigment, and 0.01-10% of photoinitiator.

[0006] WO 2020 / 182810 relates to a polymerizable radiation curable composition comprising (i) a monomer and (ii) at least one component, the monomer comprising at least (a) one first monomer having a homopolymer TG (glass transition temperature) that is equal to or greater than 120° C. and at least (b) one second monomer having a homopolymer TG (glass transition temperature) that is equal to or less than 100° C., wherein at least one of the at least one first monomer or the at least one second monomer has an alicyclic group, and the at least one further component comprises at least one photoinitiator for the UV and / or Vis region, or a photoinitiator system for the UV and / or Vis region.

[0007] European Patent Application Publication No. 3,925,994 describes a photocurable composition containing a di(meth)acrylic monomer (A) having two (meth)acryloyloxy groups and two urethane bonds, an acrylic monomer (B) having one acryloyl group, and a photopolymerization initiator.

[0008] WO 2019 / 204807 discloses a thermosetting composition suitable for use in additive manufacturing processes, comprising a high concentration of a urethane methacrylate oligomer having at least one polymerizable group and a number average molecular weight of 750 to 4000 g / mol, an effective amount of a monofunctional reactive diluent monomer, a defined concentration of a network builder having a molecular weight lower than the molecular weight of the urethane methacrylate oligomer, optionally a photoinitiator, and optionally additives.

[0009] European Patent Application Publication No. 3494954 relates to a photocurable composition used for producing dental prostheses and the like by stereolithography. The photocurable composition comprises at least a photopolymerization initiator, an acrylic monomer (X) having no aromatic ring but a ring structure other than an aromatic ring, having two or more acryloyloxy groups in one molecule, and having a Mw of 200 to 800, and a (meth)acrylic monomer (A) having one or more ether bonds in one molecule, having two (meth)acryloyloxy groups in one molecule, and having a Mw of 200 to 400. and (C) a (meth)acrylic monomer component having a hydrocarbon skeleton, two (meth)acryloyloxy groups in one molecule and an Mw of 190 to 280; and (D) a (meth)acrylic monomer component having one or more aromatic rings and one (meth)acryloyloxy group in one molecule and an Mw of 140 to 350.

[0010] US Patent Application Publication No. 2018 / 0000570 describes a method of forming a dental component, in which a polymerizable composition is used that includes a core-shell impact modifier, methyl methacrylate, and an initiator.

[0011] U.S. Patent Application Publication No. 2009 / 0192240 discloses a hardenable dental composite material comprising i) a non-aggregated nanofiller having a particle size of about 1 to about 50 nm, and ii) a core-shell polymer particle having an elastomeric core compound and a substantially non-elastomeric shell compound.

[0012] The compositions conventionally employed in additive manufacturing have the drawback of having low impact strength and therefore fracture behavior that is not suitable for dental applications. The impact strength required for dental applications is achieved by adding impact modifiers or by using phase-separated plastic materials. To fully incorporate the impact modifier into the polymer matrix, components with high vapor pressures are usually employed, which are highly volatile and cause the dental product to have an unpleasant odor. Furthermore, the addition of impact modifiers adversely affects the mechanical properties of the composition, in particular the fracture toughness and fracture work, as well as the flexural strength. Thus, there remains a need for improved compositions for the manufacture of dental products. [Means for solving the problem]

[0013] Surprisingly, it has been found that the input of pollutants into the environment by processing such materials into dental products, most of which are characterized by an unpleasant odor, can be reduced by employing compounds with lower vapor pressures, for example within additive manufacturing processes, without adversely affecting the printability of such compositions. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Accordingly, the present invention relates first to a dental hardenable composition comprising, based on the total weight of the composition, the following: a) 0.1 to 10% by weight of a binder based on monomeric monofunctional (meth)acrylates, the ester groups having a carbon chain of 3 or more carbon atoms, b) 1 to 15 wt. % of one or more core-shell impact modifiers, and c) 1 to 90% by weight of a matrix material, and d) 0.01 to 3% by weight of at least one initiator.

[0015] Surprisingly, it has been found that the composition according to the present invention can not only reduce the unpleasant odor that dental restorations usually have, but also has a higher temperature stability in liquid state, and as a result, can achieve better processability.In particular, the use of longer-chain monofunctional (meth)acrylates as binders can provide the composition with mechanical properties that can be used in the dental field.Therefore, it has been found surprisingly that the addition of the binder according to the present invention can improve the fracture toughness and fracture work of dental compositions, while bending strength remains constant.

[0016] The ester group of the binder comprises a carbon chain of 3 or more carbon atoms, which may carry further substituents. In a preferred embodiment, the carbon chain comprises 4 or more carbon atoms, preferably 5 or more carbon atoms. However, preferably, the carbon chain has 16 or less carbon atoms, so as not to adversely affect the processability of the composition. In a particularly preferred embodiment, the binder comprises a C 3 H 7 ~C 16 H 33 , preferably C 3 H 7 ~C 6 H 13 In a particularly preferred embodiment, the binder is selected from the group consisting of propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, and hexyl (meth)acrylate, and isomers thereof. Mixtures of the listed compounds can also be used.

[0017] In a preferred embodiment, the content of the binder in the composition according to the present invention is 0.2 to 7% by weight, preferably 0.5 to 5% by weight, based on the total weight of the composition.

[0018] To avoid the unpleasant odors associated with short-chain (meth)acrylates, especially methyl (meth)acrylate and ethyl (meth)acrylate, the composition according to the invention is preferably free of such compounds. In a preferred embodiment, the content of monomeric methyl (meth)acrylate and / or ethyl (meth)acrylate in the composition according to the invention is preferably less than 0.5% by weight, more preferably less than 0.5% by weight, in particular less than 0.1% by weight, respectively, based on the total weight of the composition.

[0019] The impact modifiers contained in the composition according to the invention are preferably selected from the group of silicone / (meth)acrylate and / or (meth)acrylate / (meth)acrylate-based core-shell particles. More preferably, the dais impact modifiers are core-shell particles with a silicone core and a PMMA shell, or core-shell particles with a (meth)acrylate-based core and a PMMA shell. Within the scope of the present invention, it has been found that such impact modifiers contribute to the fact that, in particular in compositions used in additive manufacturing, products with high mechanical strength and excellent physical properties are obtained.

[0020] Furthermore, the composition according to the invention comprises at least one matrix material. Preferably, said matrix material is a mono- or polyfunctional (meth)acrylate or a mixture of said compounds. More preferably, said matrix material is different from said binder material.

[0021] As the matrix material, compounds known to those skilled in the art can be used. Preferably, the matrix material is a polymerizable (meth)acrylate compound, such as cyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, allyl acrylate, isobornyl (meth)acrylate, stearyl (meth)acrylate, phenoxybenzyl (meth)acrylate, o-phenylphenolethyl (meth)acrylate, 1,14-tetradecanyl dimethacrylate, dimethylol tricyclodecanyl diacrylate, glyceryl ... Ceryl diacrylate, glyceryl triacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, tetraethylene glycol di(meth)acrylate, 1,3-propanediol diacrylate, 1,3-propanediol dimethacrylate, trimethylolpropane tri(meth)acrylate, 1,2,4-butanetriol trimethacrylate, 1,4-cyclohexanediol diacrylate, 1,4-cyclohexanediol dimethacrylate, 1,6-hexanediol di(meth)acrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, sorbitol hexaacrylate, 2,2-bis[4-{2-hydroxy-3-acryloyloxypropoxy}phenyl]propane, and 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)phenyl]propane (Bis-GMA). In particular, the matrix material is selected from the group consisting of tricyclodecane dimethanol dimethacrylate, ethylene glycol phenyl ether methacrylate, isobornyl methacrylate, 3,3,5-trimethylcyclohexyl methacrylate, and tricyclodecanyl acrylate, and mixtures thereof.

[0022] In a preferred embodiment, the composition according to the invention comprises up to 70% by weight of at least one difunctional urethane (meth)acrylate, based on the total weight of the composition. In a further preferred embodiment, the content of the difunctional urethane (meth)acrylate is at least 25% by weight, more preferably 30-45% by weight, based on the total weight of the composition. Urethane di(meth)acrylate triglycerides, in particular aliphatic polyesters / polyethers based on UDA and UDMA, are preferably used as said difunctional urethane (meth)acrylate. In this way, in particular the breaking elongation of the product produced from the composition according to the invention can be increased.

[0023] The curable composition according to the invention further comprises an initiator to initiate the curing of the composition. Such an initiator may be a thermal initiator or a photoinitiator. Preferably, the initiator is included in the curable composition in an amount of 0.01 to 2% by weight, in particular 0.5 to 1.5% by weight, based on the total weight of the curable composition. In a preferred embodiment, the initiator is selected from the group consisting of benzophenone, benzoin or α-diketone to make the composition photocurable. Preferred initiators further include camphor-quinone (CQ), or cationic initiators such as 4-octyloxyphenylphenyliodonium hexafluoroantimonate (OPPI). Further suitable initiators are those selected from the class of acylphosphine oxides, such as nonacylphosphine oxide, bisacylphosphine oxide and triacylphosphine oxide, in particular 2,4,6-trimethylbenzoyldiphenylphosphinate (TPO), and ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate (TPO-L). The hardening of the compositions according to the invention is initiated by irradiation with light having a wavelength of preferably 365-500 nm, more preferably 385-405 nm, so that instruments common in the dental field can be used. It is also preferred within the scope of the invention to use a mixture of thermal and photoinitiators. In this way, the compositions according to the invention can be molded, for example, with a 3D printer, preferably a light-based system such as DLP, LCD or stereolithography. The final hardening can be carried out by another irradiation or a heat treatment.

[0024] The hardenable composition according to the invention may contain further components to adapt its properties according to the intended application. Thus, an embodiment is preferred in which the hardenable composition further comprises an inorganic filler. Such fillers may be included in the composition according to the invention in an amount of up to 60% by weight, based on the total weight of the composition. Preferably, the inorganic filler is selected from the group consisting of silica, zirconia, aluminum oxide, alumina, apatite, titanium dioxide, and glass microbeads. Such inorganic fillers have proven to be particularly advantageous when the hardenable composition is used for the manufacture of artificial teeth.

[0025] In a further preferred embodiment, the curable composition of the present invention further comprises an organic filler, which may be present in an amount of up to 60% by weight, based on the total weight of the composition. Such organic fillers are preferably selected from the group consisting of acrylate beads, in particular PMMA beads, and rubber beads. Such fillers can be employed in particular to improve the shrinkage of the composition during curing and its mechanical properties.

[0026] In particular, when the composition according to the invention is used to manufacture artificial teeth, the composition may further contain a coloring material. The amount of coloring material in the composition depends on the desired color result, but in a preferred embodiment, it is less than 10% by weight, more preferably less than 2.5% by weight, in particular 0.1-2% by weight, based on the total weight of the composition. As coloring material, both organic and inorganic materials can be used, and inorganic coloring pigments are preferred, especially since the best results can be obtained using inorganic coloring pigments as far as the optical properties of the dental restoration are concerned.

[0027] The curable composition according to the invention preferably has a flexural modulus in the cured state of less than 5 GPa, preferably less than 5 GPa, in particular between 2 and 4 GPa, determined according to DIN EN ISO 20795-1 (2013) on printed test specimens.

[0028] The curable composition is preferably a one-part composition, thus eliminating the tedious mixing required for two-part compositions.

[0029] In particular, the hardenable composition is used for dental applications. Thus, preferred embodiments are those in which the composition is printable and processable in additive manufacturing processes. In this way, dental restorations, such as artificial teeth, can be provided with high color and precision of fit. Furthermore, preferred embodiments are those in which the hardenable composition in hardenable form is machineable, such that, for example, manual modifications can be made.

[0030] In particular, the hardenable composition of the present invention is adapted for use in dental applications.Therefore, the present invention further relates to the use of the hardenable composition of the present invention as dental material.Therefore, the composition of the present invention is used in particular for the manufacture of dental restorations such as artificial teeth and full artificial teeth and partial artificial teeth, as well as other dental products such as corrective measures for tooth position, or as an auxiliary for dental applications, for example, for the manufacture of models and templates.

[0031] The present invention further relates to dental products manufactured from the hardenable compositions according to the invention.In particular, such dental products are dental restorations such as artificial teeth, full and partial dental prostheses, and tooth position correction measures such as orthodontics or splints.In another preferred embodiment, the compositions according to the invention are used as an auxiliary in dental applications, for example for the manufacture of models or templates.

[0032] The invention further relates to a process for producing a dental product by introducing the hardenable composition of the invention into an additive manufacturing device and hardening it. Preferably, the hardenable composition is applied layer by layer, the individual layers being interconnected, for example by irradiating with light. The application of the composition can be based on data previously obtained from the patient, for example to achieve a perfect fit. The final hardening of the product is preferably performed by another irradiation or heat treatment.

[0033] The present invention will be further illustrated by the following examples, which should not be construed as limiting the scope of the invention in any way. EXAMPLES

[0034] For the preparation of the compositions, the following materials were used, with the respective values ​​in the table being understood as percentages by weight: - UDA / UDMA: Urethane diacrylate / Urethane dimethacrylate - MA: Matrix material, a mixture of mono- and polyfunctional (meth)acrylates, available from Arkema, France, Sartomer product range - MMA: Methyl methacrylate - EMA: Ethyl methacrylate - Binder 1: 2-methyl-2-propenoate butyl - Binder 2: Butyl 2-methylprop-2-enoate - Binder 3: Isopropyl methacrylate - Impact Modifier 1: Core Shell (Silicone / PMMA) - Impact Modifier 2: Core Shell ((Meth)acrylate / PMMA) - Initiator TPO-L

[0035] [Table 1]

[0036] The mechanical properties were measured as follows. Flexural strength and flexural modulus: According to DIN EN ISO 20795-1 (2013) on printed test specimens.

[0037] Work of fracture and fracture toughness (kmax): by analogy to DIN EN ISO 20795-1 (2013), specimens were printed including the initial crack and notch and measurements were performed outside the water bath.

[0038] As can be seen from the data in the table, comparative compositions D and G, which do not contain a binder, show poor mechanical properties, which can be improved by adding compounds that function as binders (see compositions AC, E and F). As can be further seen from the table, the replacement of the potentially important binders MMA and EMA with longer chain acrylates in compositions B and C does not adversely affect the mechanical properties. Rather, the flexural strength and flexural modulus remain constant, while the work of fracture and fracture toughness (kmax) can be improved by using a binder.

Claims

1. A dental hardenable composition, comprising, based on the total weight of the composition, a) 0.1 to 10% by weight of a binder based on monomeric monofunctional (meth)acrylates, the ester groups having a carbon chain of 3 or more carbon atoms; b) 1 to 15 wt. % of one or more core-shell impact modifiers, and c) 1 to 90% by weight of a matrix material, and d) 0.01 to 3 wt. % of at least one initiator; 1. A curable composition comprising:

2. wherein the ester group of the binder has up to 16 carbon atoms. The curable composition of claim 1.

3. 5. Curable composition according to at least one of the preceding claims, characterized in that the content of monomeric methyl (meth)acrylate and / or monomeric ethyl (meth)acrylate is less than 0.5% by weight, based on the total weight of the composition.

4. 10. Curable composition according to at least one of the preceding claims, characterized in that the impact modifier or modifiers are selected from the group of silicone / (meth)acrylate based core-shell particles and (meth)acrylate / (meth)acrylate based core-shell particles.

5. 4. The curable composition according to at least one of the preceding claims, characterized in that the composition comprises up to 70% by weight of at least one difunctional urethane (meth)acrylate, based on the total weight of the composition.

6. 10. The curable composition according to at least one of the preceding claims, characterized in that the initiator is selected from the group consisting of thermal initiators and photoinitiators.

7. 10. The hardenable composition according to at least one of the preceding claims, characterized in that the composition further comprises up to 60% by weight, based on the total weight of the composition, of an inorganic filler, preferably selected from the group consisting of silica, zirconia, aluminum oxide, alumina, apatite, titanium dioxide and glass microbeads.

8. 10. The curable composition according to at least one of the preceding claims, characterized in that the composition further comprises up to 60% by weight, based on the total weight of the composition, of an organic filler, preferably selected from the group consisting of (meth)acrylate beads, in particular PMMA beads, and rubber beads.

9. 4. The curable composition according to at least one of the preceding claims, characterized in that the composition further comprises up to 10% by weight of a coloring substance, based on the total weight of the composition.

10. 10. Curable composition according to at least one of the preceding claims, characterized in that the composition is printable.

11. 20. Use of a composition according to at least one of the preceding claims as a dental material and / or as an adjuvant for dental applications.

12. A dental product made from a hardenable composition according to at least one of claims 1 to 10.

13. 11. A method of producing a dental product by introducing the hardenable composition according to at least one of claims 1 to 10 into an additive manufacturing apparatus and hardening.

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