Hardenable compositions for use in methods of treating dental conditions in a patient's oral cavity

Abstract

The present invention relates to a hardenable composition for use in a process of treating a dental condition in a patient's oral cavity, comprising: radiation-curable component(s); photoinitiator(s), wherein the photoinitiator exhibits absorption in the UV light region and absorption in the visible light region, wherein the absorption in the UV light region is stronger than the absorption in the visible light region; optionally filler(s); and optionally additive(s), wherein the process comprises the steps of layer-by-layer additive manufacturing of a dental or orthodontic article using radiation having a wavelength in the UV light region; attaching the dental or orthodontic article to a surface of dental hard tissue or dental material; and applying radiation having a wavelength in the visible light region to the dental or orthodontic article.

Description

[Technical Field]

[0001] The present invention relates to a hardenable composition and related kit for use in a method of treating a dental condition in a patient's oral cavity. The hardenable composition comprises radiation-curable component(s), a photoinitiator having a specific absorption spectrum, and optionally filler(s) and additive(s), and is curable by UV and visible light. [Background technology]

[0002] The use of additive manufacturing techniques, particularly 3D printing, to produce dental articles is known in the art. However, articles produced by 3D printing, in particular, cannot be used directly and typically require post-processing steps.

[0003] Post-processing typically includes cleaning or removing uncured resin from the article after it has been removed from the print tank, and removing the pins that support the article during the printing process.

[0004] Furthermore, 3D printed articles typically need to be post-cured to obtain articles with sufficient mechanical properties. Depending on the application, the conditions used for the 3D printing process and post-curing step will vary, particularly with regard to the wavelength of radiation used for curing.

[0005] In the dental field, curing of radiation-curable compositions in the patient's mouth may not be done with UV light, even though this would be more effective, whereas 3D printing is typically done with UV light.

[0006] Therefore, depending on the intended application, it is necessary to select an appropriate photoinitiator that is sensitive to the respective wavelengths of light used for either 3D printing and post-curing.

[0007] To address this need, radiation-curable compositions containing two different types of photoinitiators have been proposed.

[0008] For example, WO 2013 / 153183(A2) (Ivoclar) discloses a method for producing dental molding components based on composite resins, comprising: (a) at least one multireactive binder; (b) a first photoinitiator having an absorption maximum at a wavelength of less than 400 nm; (c) a second photoinitiator having an absorption maximum at a wavelength of at least 400 nm; and (d) an absorber having an absorption maximum at a wavelength of less than 400 nm for the stereolithographic production of dental molding components based on composite resins. The present invention describes the use of a composite resin composition containing: Summary of the Invention

[0009] However, there remains a need for radiation-curable compositions that, on the one hand, can be economically processed by additive manufacturing processes to obtain articles with suitable mechanical properties, and, on the other hand, allow the provision of articles that still contain a sufficiently high amount of uncured portions available for light-induced adhesive fixation of the article to the dental hard tissue.

[0010] If desired, the mechanical properties of the article obtained by the additive manufacturing process should also allow for mechanical manipulation of the 3D printed article before further processing such as trimming or cutting.

[0011] Ideally, the degree of undesired light scattering during the additive manufacturing process should also be reduced.

[0012] Additionally, it may be desirable for the 3D printed article to have high flexibility after the 3D printing process, allowing the 3D printed article to be more easily placed onto another object, even an object with an undercut.

[0013] At least one of the above objectives is addressed by the present invention as described herein and in the claims.

[0014] In particular, the present invention relates to a hardenable composition for use in a method of treating a dental condition in a patient's oral cavity, The curable composition comprises a radiation curable component(s); photoinitiator(s), which exhibits absorption in the UV light region and absorption in the visible light region, the absorption in the UV light region being stronger than the absorption in the visible light region; Optionally, filler(s); and optionally additive(s), The process is additively manufacturing a dental or orthodontic article layer-by-layer using radiation having a wavelength in the UV light range; attaching the dental or orthodontic article to a surface of dental hard tissue or dental material; applying radiation having a wavelength in the visible light range to the dental or orthodontic article.

[0015] The present invention also relates to a kit of parts comprising a hardenable composition for use as described herein, a dental adhesive or dental cement, optionally a dental positioning tray, and optionally instructions for use.

[0016] Additionally, the present invention relates to a pre-hardened composition obtainable by processing the hardenable composition described herein in an additive manufacturing process, the pre-hardened composition having the shape of a dental or orthodontic article. [Brief explanation of the drawings]

[0017] [Figure 1] 1 shows the UV / VIS spectrum of camphorquinone. [Figure 2] 1 shows the UV / VIS spectrum of phenyl-1,2-propanedione. [Figure 3] 1 shows flexural strength testing of 3D printed articles obtained from curable compositions described herein. DETAILED DESCRIPTION OF THE INVENTION

[0018] The term "compound" or "component" is a chemical substance having a particular molecular identity or consisting of a mixture of such substances, for example, a polymeric substance.

[0019] A "hardenable or curable or polymerizable component" is any component that can be cured or hardened by radiation-induced polymerization in the presence of a photoinitiator. The hardenable component may contain only one, two, or more than two polymerizable groups. Typical examples of polymerizable groups include unsaturated carbon groups, such as vinyl groups present in (methyl)acrylate groups, among others.

[0020] As used herein, "(meth)acryl" is an abbreviation for "acryl" and / or "methacryl." For example, a "(meth)acryloxy" group is an abbreviation for either an acryloxy group (i.e., CH2=CH-C(O)-O-) and / or a methacryloxy group (i.e., CH2=C(CH3)-C(O)-O-).

[0021] A "urethane group" is a group having the structure "-NH-CO-O-."

[0022] As used herein, "solidifying" or "curing" a composition are used interchangeably and refer to polymerization and / or crosslinking reactions, including, for example, photopolymerization reactions and chemical polymerization techniques (e.g., chemical reactions that form radicals effective to polymerize ethylenically unsaturated compounds), involving one or more materials included in the composition.

[0023] "Radiation-curable" shall mean that the component (or composition, as the case may be) can be cured by the application of radiation, preferably electromagnetic radiation at wavelengths in the light spectrum of 350 nm to 500 nm under ambient conditions and within a suitable time frame (e.g., within about 15, 10, or 5 minutes).

[0024] "Dental article" refers to an article used in the fields of dentistry or orthodontics. Dental articles typically have two different surface portions: an outer surface and an inner surface. The outer surface is typically a surface that does not permanently contact the tooth surface. In contrast, the inner surface is a surface used to attach or fix the dental article to the tooth. When the dental article has the shape of a dental crown, the inner surface typically has a concave shape, while the outer surface typically has a convex shape. Dental articles should not contain ingredients that are harmful to the patient's health, and therefore do not contain harmful or toxic ingredients that may leak from dental or orthodontic articles.

[0025] "Orthodontic articles" include orthodontic brackets, buccal tubes, lingual retainers, orthodontic bands, bite openers, buttons, attachments, and cleats.

[0026] "Dental hard tissue" includes enamel and dentin.

[0027] "Particle" means a solid substance having a geometrically determinable shape. The shape may be regular or irregular. Particles can typically be analyzed, for example, with respect to particle size and particle size distribution.

[0028] "Agglomerated" describes a weak association of particles, usually held together by charge or polarity, that can be broken down into smaller entities. The specific surface area of ​​the agglomerated particles does not deviate substantially from the specific surface area of ​​the primary particles that make up the agglomerate (see DIN 53206; 1972).

[0029] Agglomerated fillers are commercially available, for example, from Degussa, Cabot Corp or Wacker under the product names Aerosil™, CAB-O-SIL™ and HDK.

[0030] "Non-agglomerated or discrete filler particles" means that the filler particles are present in the resin in a discrete, non-associated (i.e., non-agglomerated and non-aggregated) state. If desired, this can be verified by TEM electron microscopy.

[0031] Non-aggregated nano-sized silica is commercially available, for example, from Nalco Chemical Co. (Naperville, Ill.) under the product name NALCO COLLOIDAL SILICAS, e.g., NALCO product #s 1040, 1042, 1050, 1060, 2327, and 2329.

[0032] Non-agglomerating fillers are used and described, for example, in U.S. Patent No. 8,329,776 (B2) to Hecht et al., the contents of which are incorporated herein by reference.

[0033] As used herein, "aggregated" describes a strong association of particles, often bonded together, for example, by residual chemical treatment or partial sintering. The specific surface area of ​​the aggregated particles is typically smaller than the specific surface area of ​​the primary particles that make up the aggregate (see DIN 53206; 1972).

[0034] "Nanofiller" is a filler whose individual particles have a size in the nanometer range, for example, an average particle size of less than 200 nm, or less than 100 nm, or less than 50 nm. Useful examples are described in U.S. Patent No. 6,899,948 (Zhang et al.) and U.S. Patent No. 6,572,693 (Wu et al.). The contents relating to nano-sized silica particles are incorporated herein by reference.

[0035] "Additive manufacturing" or "3D printing" refers to a process that involves the layer-by-layer creation of an object from digital data. The article can be of almost any shape or geometry and is created from a three-dimensional model or other electronic data source.

[0036] There are many 3D printing technologies, one of which is bath polymerization, which uses a radiation curing process to create three-dimensional articles. Examples of bath polymerization technologies include stereolithography (SLA) and digital light processing (DLP).

[0037] "Stereolithography" is an example of an additive manufacturing technique that typically uses two motors to aim a laser beam across the print area, thereby solidifying the printing resin. This method breaks down the design into a series of points, layer by layer.

[0038] "Digital light fabrication" is another example of an additive manufacturing technique and typically involves the use of a digital projector screen to flash an image of each layer across the build platform of an additive manufacturing unit. The image is typically made up of square pixels, resulting in layers made up of small rectangular bricks called voxels.

[0039] "UV light region" means light having a wavelength in the range of 350 nm to 410 nm.

[0040] "Visible light region" refers to light having a wavelength in the range of 440 nm to 500 nm.

[0041] "Ambient conditions" refers to the conditions to which the compositions described herein are typically exposed during storage and handling. Ambient conditions may be, for example, a pressure of 900 mbar to 1,100 mbar, a temperature of 10°C to 40°C, and a relative humidity of 10% to 100%. In the laboratory, ambient conditions are typically adjusted to 20°C to 25°C and 1,000 mbar to 1,025 mbar (at sea level pressure).

[0042] As used herein, "a," "an," "the," "at least one," and "one or more" are used interchangeably. Also herein, the recitation of numerical ranges by endpoints includes all numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0043] Adding "(s)" to a term means that the term is to include the singular and the plural. For example, the term "additive(s)" means one additive and more (e.g., two, three, four, etc.) additives.

[0044] Unless otherwise indicated, all numbers expressing quantities of ingredients, measurements of physical properties, and the like set forth below and used in the specification and claims are to be understood as modified in all instances by the term "about."

[0045] The terms "comprise" or "contain" and variations thereof do not have a limiting meaning when these terms appear in the specification and claims. "Consisting essentially of" means that certain additional components may be present, i.e., components that do not materially affect the essential properties of the article or composition. "Consisting of" means that no additional components should be present. The term "comprise" is also intended to encompass the terms "consist essentially of" and "consists of."

[0046] If a composition does not contain a particular component as an essential feature, the composition is "essentially or substantially free of" that component. Thus, the component is not intentionally added to the composition, either as is or in combination with other components or elements of other components. A composition that is essentially free of a particular component typically does not contain that component at all. However, the presence of a small amount of the component may be unavoidable, for example, due to impurities contained in the raw materials used. "Essentially free" typically means a content of less than 1, 0.5, or 0.1% by weight.

[0047] The present invention is advantageous for several reasons.

[0048] The photoinitiators described herein absorb light not only in the visible range but also in the UV range, which is an advantage over, for example, the photoinitiator camphor quinone (CQ), which absorbs primarily in the visible range as shown in Figure 1.

[0049] In Figure 1, the absorption spectrum of CQ is shown as A, the emission spectrum of a typical 3D printing device is shown as B, and the emission spectrum of a typical dental curing light device is shown as C.

[0050] The photoinitiators described herein are sensitive not only to light typically used in additive manufacturing equipment, but also to light typically used in dental curing lights. This is shown in Figure 2 for the photoinitiator phenyl-1,2-propanedione (PPD).

[0051] In Figure 2, the absorption spectrum of PPD is shown as A, the emission spectrum of a typical 3D printing device is shown as B, and the emission spectrum of a typical dental curing light device is shown as C.

[0052] Furthermore, the absorption of the photoinitiator in the UV light region is high enough to obtain a pre-cured article with suitable mechanical properties, especially high flexibility.

[0053] The flexibility of pre-cured articles can even be so high that a typical determination of flexural strength is not possible because the test bars used for the measurements do not break. Thus, pre-cured articles can be considered to be completely elastic or elastomeric. This is shown in Figure 3.

[0054] However, the resulting pre-cured article still contains a sufficiently high amount of uncured portions and photoinitiator to not only harden the pre-cured article at a later stage, but also to provide the option of adhesively fixing the pre-cured article to dental hard tissue or to adhesively fix the pre-cured article to other dental materials, the adhesive fixation being triggered by a light-induced curing process in the visible light range.

[0055] The photoinitiators described herein are also aesthetically pleasing because they are essentially colorless or have only a slight yellow color in the visible light range, and therefore the color of dental or orthodontic articles obtained by radiation curing a hardenable composition containing this photoinitiator is not adversely affected or is not affected, and does not exhibit undesirable discoloration after curing.

[0056] Because the photoinitiator is essentially colorless, it can also be used in comparable high amounts without adversely affecting aesthetic properties, allowing for high process flexibility during the additive manufacturing process and, if desired, high conversion rates of the curable part.

[0057] Furthermore, because the photoinitiator exhibits high absorption and sensitivity in the UV light region, the curing reaction during the additive manufacturing process proceeds quickly, allowing for economical production of pre-cured articles.

[0058] These properties are particularly useful in dental or orthodontic procedures requiring extraoral pre-curing and a final intraoral post-curing step, for example, for producing preformed dental composite crowns, orthodontic attachments for clear tray aligners, and / or orthodontic brackets.

[0059] The hardenable compositions described herein are for use in methods of treating dental conditions in a patient's mouth.

[0060] The curable composition includes one or more radiation-curable components, a photoinitiator for curing the radiation-curable components, optionally a filler(s), and optionally an additive(s).

[0061] The curable compositions described herein can be characterized as one-part photocurable compositions.

[0062] Curable compositions typically have the following characteristics: a. Viscosity: 23℃ and 1s -1 <50 Pa at shear rates * s, or 23°C, 1 s -1 at a shear rate of 1 Pa * s~40Pa * be within the range of less than s; b. It is curable by radiation having a wavelength in the range of 350 nm to 500 nm. The compounds can be further characterized by the following, either alone or in combination:

[0063] Viscosities of the curable composition within the above ranges have been found to be particularly suitable for processing the curable composition in additive manufacturing processes.

[0064] The radiation-curable component is typically a component that contains one or more ethylenically unsaturated moieties.

[0065] The radiation curable component can be selected from (meth)acrylate components, urethane (meth)acrylate components, and mixtures thereof. When a mixture of (meth)acrylate components is used, the urethane (meth)acrylate component may be preferred.

[0066] The radiation-curable component(s) are typically present in the following amounts: at least 20% by weight, or at least 25% by weight, or at least 30% by weight of the curable composition; up to 95% by weight, or up to 90% by weight, or up to 80% by weight; 20% to 95% by weight, or 25% to 90% by weight, or 30% to 80% by weight; the weight percentages are based on the curable composition.

[0067] The curable composition may include one or more (meth)acrylate components that do not include a urethane moiety.

[0068] The (meth)acrylate(s) that do not include a urethane moiety differ from the urethane (meth)acrylates, for example, with respect to functionality, chemical moieties, molecular weight, or a combination thereof.

[0069] The (meth)acrylate component that does not contain a urethane moiety can typically be characterized by the following properties, either alone or in combination: a) containing at least two (meth)acrylate moieties; b) molecular weight of 170 g / mol to 1,000 g / mol.

[0070] Examples include di- or poly-acrylates and methacrylates such as glycerol diacrylate, glycerol triacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, 1,3-propanediol diacrylate, 1,3-propanediol dimethacrylate, trimethylolpropane triacrylate, 1,2,4-butanetriol trimethacrylate, 1,4-cyclohexanediol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, sorbitol hexaacrylate, bis[1-(2-acryloxy)]-p-ethoxyphenyldimethylmethane, bis[1-(3-acryloxy-2-hydroxy)]-p-propoxy-phenyl-dimethylmethane; bis-acrylates and bis-methacrylates of polyethylene glycols having molecular weights of 200 to 500, and copolymerizable mixtures of acrylated monomers. Suitable monomers are also described, for example, in US Pat. No. 4,652,274 (Boettcher et al.) and US Pat. No. 4,642,126 (Zador et al.), the contents of which are incorporated herein by reference.

[0071] Preferred ethylenically unsaturated monomers are methacrylate and acrylate monomers, such as the di(meth)acrylates of propanediol, butanediol, hexanediol, octanediol, nonanediol, decanediol and eicosanediol, the di(meth)acrylates of ethylene glycol, polyethylene glycol and polypropylene glycol, the di(meth)acrylates of ethoxylated bisphenol A, such as 2,2'-bis(4-(meth)acryloxytetraethoxyphenyl)propane, and (meth)acrylamide. The monomers used may also be esters of [alpha]-cyanoacrylic acid, crotonic acid, cinnamic acid and sorbic acid.

[0072] Bis[3[4]-methacryl-oxymethyl-8(9)-tricyclo[5.2.1.0 2,6It is also possible to use methacrylic acid esters, including those mentioned in U.S. Pat. No. 4,795,823 (Schmitt et al.), including decylmethyl triglycolate. Examples of suitable methacrylic acid esters include 2,2-bis-4(3-methacryloxy-2-hydroxypropoxy)phenyl-propane (Bis-GMA), 2,2-bis-4(3-methacryloxypropoxy)phenylpropane, triethylene glycol dimethacrylate (TEGDMA), and bishydroxymethyltricyclo-(5.2.1.0). 2,6 The di(meth)acrylate of decane is also suitable.

[0073] If desired, the curable composition may also include a (meth)acrylate component containing only one (meth)acrylate moiety, such as, for example, methyl acrylate, methyl methacrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-hexyl (meth)acrylate, stearyl (meth)acrylate, allyl (meth)acrylate, glycerol di(meth)acrylate, and mixtures thereof.

[0074] Suitable compounds also include 2-hydroxyethyl(meth)acrylate (HEMA), 2- or 3-hydroxypropyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate, 5-hydroxypentyl(meth)acrylate, 6-hydroxyhexyl(meth)acrylate, 10-hydroxydecyl(meth)acrylate, dialkylene glycol mono(meth)acrylates such as diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tetra-ethylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, dipropylene glycol mono(meth)acrylate, Examples of suitable hydroxypropyl acrylates include pyrene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, and also include 1,2- or 1,3- and 2,3-dihydroxypropyl(meth)acrylate, 2-hydroxypropyl-1,3-di(meth)acrylate, 3-hydroxypropyl-1,2-di(meth)acrylate, N-(meth)acryloyl-1,2-dihydroxypropylamine, N-(meth)acryloyl-1,3-dihydroxypropylamine, adducts of phenol and glycidyl(meth)acrylate, such as 1-phenoxy-2-hydroxypropyl(meth)acrylate, and 1-naphthoxy-2-hydroxypropyl(meth)acrylate.If desired, one or more of these components can be used in combination.

[0075] When present, and when present in combination with other polymerizable components such as a urethane (meth)acrylate component, the (meth)acrylate component is typically present in the following amounts: at least 20 wt%, or at least 25 wt%, or at least 30 wt%; up to 75 wt%, or up to 70 wt%, or up to 65 wt%; 20 wt% to 75 wt%, or 25 wt% to 70 wt%, or 30 wt% to 65 wt%; the weight percentages are based on the curable composition.

[0076] The curable composition may also include one or more urethane (meth)acrylates.

[0077] Urethane (meth)acrylates typically contain at least two (meth)acrylate moieties and at least two urethane moieties.

[0078] The molecular weight of the urethane (meth)acrylate is at least 400 g / mol, or at least 800 g / mol, or at least 1,000 g / mol.

[0079] Useful ranges include 400 g / mol to 3,000 g / mol, or 800 g / mol to 2,700 g / mol, or 1,000 g / mol to 2,500 g / mol.

[0080] The urethane (meth)acrylates used in the compositions are typically obtained by reacting an NCO-terminated compound with a suitable monofunctional (meth)acrylate monomer, such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, preferably hydroxyethyl and hydroxypropyl methacrylate.

[0081] Urethane (meth)acrylates can be obtained by many methods known to those skilled in the art.

[0082] For example, a polyisocyanate may be reacted with a polyol to form an isocyanate-terminated urethane prepolymer, which may then be reacted with a (meth)acrylate, such as 2-hydroxyethyl (meth)acrylate. These types of reactions can be carried out at room temperature or at higher temperatures, optionally in the presence of a catalyst, such as a tin catalyst, a tertiary amine, or the like.

[0083] The polyisocyanate that can be used to form the isocyanate-functional urethane prepolymer can be any organic isocyanate having at least two free isocyanate groups, including aliphatic, cycloaliphatic, aromatic, and araliphatic isocyanates.

[0084] Any of the known polyisocyanates can be used, including combinations such as alkyl and alkylene polyisocyanates, cycloalkyl and cycloalkylene polyisocyanates, and alkylene and cycloalkylene polyisocyanates.

[0085] Preferably, diisocyanates having the formula X(NCO)2 are used, where X represents an aliphatic hydrocarbon radical having 2 to 12 C atoms, an alicyclic hydrocarbon radical having 5 to 18 C atoms, an aromatic hydrocarbon radical having 6 to 16 C atoms and / or an alicyclic hydrocarbon radical having 7 to 15 C atoms.

[0086] Examples of suitable polyisocyanates include 2,2,4-trimethylhexamethylene-1,6-diisocyanate, hexamethylene-1,6-diisocyanate (HDI), cyclohexyl-1,4-diisocyanate, 4,4'methylene-bis(cyclohexyl isocyanate), 1,1'-methylenebis(4-isocyanato)cyclohexane, isophorone diisocyanate, 4,4'-methylenediphenyl diisocyanate, 1,4-tetramethylene diisocyanate (diis ocycanate, meta- and para-tetramethylxylene diisocycanate, 1,4-phenylene diisocycanate, 2,6- and 2,4-toluene diisocycanate, 1,5-naphthylene diisocycanate, 2,4'- and 4,4'-diphenylmethane diisocycanate, and mixtures thereof.

[0087] It is also possible to use the high-functionality polyisocyanates known from polyurethane chemistry or modified polyisocyanates containing, for example, carbodiimide, allophanate, isocyanurate and / or biuret groups. Particularly preferred isocyanates are isophorone diisocyanate, 2,4,4-trimethyl-hexamethylene diisocyanate and high-functionality polyisocyanates with an isocyanurate structure.

[0088] The isocyanate-terminated urethane compound is capped with a (meth)acrylate to form a urethane (meth)acrylate compound. Generally, any (meth)acrylate-type capping agent having a terminal hydroxyl group and also having an acrylic or methacrylic moiety (methacrylic moiety is preferred) can be used.

[0089] Examples of suitable capping agents include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, glycerol di(meth)acrylate, and / or trimethylolpropane di(meth)acrylate. Particularly preferred are 2-hydroxyethyl methacrylate (HEMA) and / or 2-hydroxyethyl acrylate (HEA).

[0090] The equivalent ratio of isocyanate groups to compounds reactive with isocyanate groups is 1.1:1 to 8:1, preferably 1.5:1 to 4:1.

[0091] The isocyanate polyaddition reaction can be carried out in the presence of catalysts known from polyurethane chemistry, such as organotin compounds such as dibutyltin dilaurate or amine catalysts such as diazabicyclo[2.2.2]octane. Furthermore, the synthesis can be carried out in the melt or in a suitable solvent, which can be added before or during the prepolymer preparation. Suitable solvents include, for example, acetone, 2-butanone, tetrahydrofuran, dioxane, dimethylformamide, N-methyl-2-pyrrolidone (NMP), ethyl acetate, alkyl ethers of ethylene and propylene glycol, and aromatic hydrocarbons. The use of ethyl acetate as the solvent is particularly preferred.

[0092] Suitable examples of urethane (meth)acrylates include 7,7,9-trimethyl-4,13-dioxo-3,14-dioxa-5,12-diazahexadecane-1,16-dioxy-dimethacrylate (e.g., Plex™ 666-1, Rohm), urethane (meth)acrylates derived from 1,4 and 1,3-bis(1-isocyanato-1-methylethyl)benzene (e.g., those described in EP 0 934 926 A1), and mixtures thereof.

[0093] According to one embodiment, the urethane (meth)acrylate is characterized as follows: Structure A-(-S1-U-S2-MA) n and A is a connector element containing at least one unit, S1 is a spacer group comprising at least four units linked together; S2 is a spacer group comprising at least four units linked together; The A, S1 and S2 units are independently

[0094] [ka] is selected from R 1 and R 2are independently selected from hydrogen, alkyl, substituted alkyl, alkenyl, cycloalkyl, substituted cycloalkyl, arylalkyl, aryl, or substituted aryl, and these units can form linear, branched, or cyclic structures such as alkyl, cycloalkyl, aryl, ester, urethane, or amide groups; U is a urethane group connecting the spacer groups S1 and S2; MA is an acrylate or methacrylate group; n is 3 to 6.

[0095] According to one embodiment, the urethane (meth)acrylate has the following structure: A(-S1-U-S2-MA) n [In the formula, A is a connector element comprising at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 units; S1 is a spacer group consisting of units linked together and comprising at least 4, 5, 6, 7, 8, 9 or 10 units; S2 is a spacer group consisting of linked units and containing at least 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, or 25 units; U is a urethane group connecting the spacer groups S1 and S2; MA is an acrylate or methacrylate group; n is 3 to 6, or 4 to 6, or 5 to 6.

[0096] It may be preferred if A has a cyclic structure and contains at least about 6 units.

[0097] It may be further preferred if S1 has a linear or branched structure and comprises at least 4 or 6 units.

[0098] It may be further preferred if S2 has a linear or branched structure and comprises at least 6 or 8 units.

[0099] Urethane (meth)acrylates in which A has a cyclic structure and contains at least 6 units, S1 has a linear structure and contains at least 4 units, S2 has a linear structure and contains at least 8 units, and U is a urethane group may also be preferred.

[0100] Neither the atoms of the urethane group connecting S1 and S2 nor the atoms of the (meth)acrylic group belong to the spacer group S1 or S2, and therefore the atoms of the urethane group are not counted as units of the spacer group S1 or S2.

[0101] The nature and structure of the connector element is not particularly limited: it can contain saturated (no double bonds) or unsaturated (at least one or two double bonds) units, aromatic or heteroaromatic units (aromatic structures containing atoms including N, O, and S).

[0102] Specific examples of connector elements A having a ring structure include the following:

[0103] [ka]

[0104] Specific examples of connector elements A that are acyclic but have a branched structure include the following:

[0105] [ka]

[0106] The dotted line indicates the bond to the spacer group S1.

[0107] The nature and structure of the spacer group S1 or S2 are also not particularly limited.

[0108] The spacer group is made up of units linked together. Typical units include:

[0109] [ka] In the formula, R 1 and R 2 are independently selected from hydrogen, alkyl, substituted alkyl, alkenyl, cycloalkyl, substituted cycloalkyl, arylalkyl, aryl, or substituted aryl.

[0110] These units can form linear, branched or cyclic structures such as alkyl, cycloalkyl, aryl, ester, urethane or amide groups.

[0111] The structure of S1 can be identical to the structure of S2. However, in some embodiments, the structure of S1 is different from S2. In specific embodiments, the number of units present in S1 is less than or equal to the number of units present in S2.

[0112] In specific embodiments, S1 can have a saturated hydrocarbon structure.

[0113] In another specific embodiment, S2 can have a saturated hydrocarbon structure.

[0114] Typical examples of useful spacer groups for S1 include the following:

[0115] [ka] Examples include:

[0116] The dotted lines indicate chemical bonds to either group A or group U.

[0117] Typical examples of useful spacer groups for S2 include the following:

[0118] [ka] Examples include:

[0119] The dotted line indicates the chemical bond to either the (meth)acrylate group or to the group U. The number of units counted according to the invention is given in brackets.

[0120] Specific examples of urethane (meth)acrylates include the following:

[0121] [ka] Examples include:

[0122] Further suitable urethane (meth)acrylates can be based on alpha-omega terminated poly(meth)acrylatdiols (e.g., as described in EP 1242493 B1) or polyester, polyether, polybutadiene or polycarbonate urethane (meth)acrylates (e.g., as described in U.S. Pat. No. 6,936,642 B2).

[0123] When present, the urethane (meth)acrylate is typically present in an amount of: at least 5, or at least 8, or at least 10% by weight; up to 30, or up to 25, or up to 20% by weight; 5-30, or 8-25, or 10%-20% by weight; The weight percentages are based on the curable composition.

[0124] The (meth)acrylate that does not contain a urethane moiety is typically used in excess by weight over the (meth)acrylate that does contain a urethane moiety.

[0125] The ratio of ((meth)acrylate not containing a urethane moiety) / ((meth)acrylate containing a urethane moiety) is usually in the range of 10 / 1 to 2 / 1 by weight.

[0126] The curable composition also includes one or more photoinitiators.

[0127] Suitable photoinitiators are those capable of initiating or initiating the curing reaction of the radiation-curable component upon radiation. In this regard, the photoinitiators described herein are capable of generating free radicals upon exposure to radiation in the wavelength ranges described herein, i.e., the visible light range and the UV light range.

[0128] These photoinitiators are also called multi-wavelength photoinitiators.

[0129] The curable composition typically contains only photoinitiator(s) that have absorption bands in the UV and visible light regions.

[0130] According to one embodiment, the curable composition comprises only one photoinitiator.

[0131] The photoinitiators described herein have special absorption behavior.

[0132] The absorption spectrum covers not only the UV light region but also the visible light region, so the absorption spectrum contains two regions, one for absorbing UV light and one for absorbing visible light, and the absorption in the UV light region is stronger than the absorption in the visible light region.

[0133] Stronger absorption means that at a given wavelength, the absorption curve or value obtained from the UV / VIS spectrometer lies above the absorption curve or value at a different wavelength.

[0134] For the photoinitiators described herein, the ratio of the absorbance in the range of 350 nm to 410 nm, particularly 390 nm, to the absorbance in the range of 440 nm to 500 nm, particularly 450 nm, is typically in the range of 1.05 to 13, or 1.10 to 10, or 1.15 to 5.

[0135] Additionally, certain embodiments of photoinitiators are typically non-fluorescent.

[0136] The photoinitiator may contain a diketone moiety, a titanocene moiety, or an acylgermanium moiety.

[0137] Examples of suitable photoinitiators include components containing a phenyl-1,2-propanedione (PPD) moiety, components containing a benzyl moiety, bis(cyclopentadienyl)bis[2,6-difluoro-3-(1-pyrryl)phenyltitanium (Omnirad™ 784), components containing a monoacyl or diacylgermanium moiety, and mixtures thereof.

[0138] The formula for each part is as follows: Shown below.

[0139] [ka]

[0140] In particular, components containing phenyl-1,2-propanedione moieties have been found to be useful because the 3D articles obtained by radiation curing of the respective curable compositions exhibit essentially no discoloration after the second curing step. Furthermore, components containing phenyl-1,2-propanedione moieties are typically liquids, which facilitates mixing with the other components of the radiation-curable composition.

[0141] Photoinitiators are often used in combination with an activator, which is often a tertiary amine.

[0142] Suitable examples of tertiary amines include N,N-dimethyl-p-toluidine, N,N-dimethyl-aminoethyl methacrylate (DMAEMA), triethanolamine, methyl 4-dimethylaminobenzoate, ethyl 4-dimethyl-aminobenzoate (EDMAB), methyl-diphenyl-amine, 4-(N,N-dimethylamino)phenethyl alcohol (DMPOH), and isoamyl 4-dimethylaminobenzoate.

[0143] The photoinitiator, optionally in combination with the activator, is present in the following amounts: lower limit: at least 0.01, at least 0.02, or at least 0.03 wt. %; upper limit: up to 5, up to 4, or up to 3 wt. %; range: 0.01-5, or 0.02-4, or 0.03 wt. % to 3 wt. %, where the wt. % is based on the curable composition.

[0144] The hardenable composition may also include one or more filler(s). The nature of the filler is not particularly limited, as long as the intended use is achieved.

[0145] Suitable fillers include non-acid-reactive glasses such as lanthanum glass, borosilicate glass, soda glass, barium glass, strontium glass, glass ceramics, aluminosilicate glass, barium boroaluminosilicate glass, strontium boroaluminosilicate glass; silicates such as calcium silicate, zirconium silicate; and metal oxides such as quartz, cristobalite, alumina, titania, silica-titania, silica-titania-barium oxide, silica-zirconia, silica-alumina, and mixtures thereof.

[0146] Fillers that can also be used include fillers comprising discrete nano-sized filler particles, agglomerated filler particles, and mixtures thereof can be used.

[0147] Compositions containing nanosized filler particles are typically clearer than compositions containing larger filler particles.

[0148] The average particle size of the nano-sized filler particles is 40 nm or less, or 35 nm or less, or 30 nm or less. The average particle size is typically in the range of 10 nm to 40 nm, or 10 nm to 35 nm, or 10 nm to 30 nm.

[0149] The specific surface area (BET) of the nano-sized filler is preferably 80 m 2 / g or more, or 100m2 / g or more, or 120m 2 The specific surface area (BET) is typically 80 m 2 / g~500m 2 / g, or 100m 2 / g~400m 2 / g, or 120m 2 / g~300m 2 / g range.

[0150] If desired, the specific surface area can be determined according to Brunauer, Emmett and Teller (BET) by using an apparatus available from Quantachrome (Monosorb™).

[0151] The nanosized fillers comprise, contain, consist essentially of, or consist of aggregated nanosized particles, which can be demonstrated, if desired, by transmission electron microscopy (TEM).

[0152] Filler particles typically comprise oxides of Si, Zr, Al and mixtures thereof, with oxides of Si and Zr sometimes being preferred.

[0153] Suitable fumed silicas include, for example, Aerosil™ series OX-50, -130, -150, and -200, Aerosil™ R8200, R805 available from Evonik, CAB-O-SIL™ M5 available from Cabot Corp (Tuscola), and HDK types available from Wacker, such as products sold under the trade names HDK™-H2000, HDK™ H15, HDK™ H18, HDK™ H20, and HDK™ H30.

[0154] Nanosized silica is commercially available from Nalco Chemical Co. (Naperville, IL) under the product name NALCO™ COLLOIDAL SILICAS. For example, preferred silica particles can be obtained using NALCO™ products 1040, 1042, 1050, 1060, 2327, and 2329. Other suitable nano-sized silicas are commercially available from Covestro (Leverkusen, Germany) under the product name Dispercoll™ (e.g., Dispercoll™ S 3030 or Dispercoll™ S 4020), from Grace GmbH & Co. KG (Worms, Germany) under the product name Ludox™ (e.g., Ludox™ P-X30 or Ludox™ P-W30), and from Nouryon (Amsterdam, Netherlands) under the product name Levasil™ (e.g., Levasil™ CS50-34P).

[0155] The aggregated filler particles typically comprise nanoclusters.

[0156] Compared to other fillers, the use of nanocluster(s) can be beneficial as it allows for the formulation of compositions with higher filler loadings that result in better mechanical properties, such as abrasiveness or wear resistance, and higher aesthetics.

[0157] Suitable nanofillers comprising agglomerated nano-sized particles can be prepared, for example, according to the process described in Preparative Examples A and B of US Pat. No. 6,730,156 (Windisch et al.).

[0158] Once dispersed in the resin, the filler particles remain in the aggregated stage, i.e., they are not broken down into discrete (i.e., individual) and non-associated (i.e., non-aggregated) particles during the dispersion process.

[0159] The nano-sized filler particles are typically surface treated.

[0160] The surface treatment allows for easier dispersion of the nano-sized filler particles in the monomer matrix and may prevent settling of the filler from the formulation during storage.

[0161] Useful surface treatment agents include silanes.

[0162] The silane surface treatment agent may contain polymerizable moieties, in particular (meth)acrylate moieties, or may be free of polymerizable moieties. Only one silane surface treatment agent or a mixture of different silane treatment agents can be used.

[0163] In a specific embodiment, a mixture of silane surface treatment agents containing polymerizable moieties, particularly (meth)acrylate moieties, and silane surface treatment agents not containing polymerizable moieties is used.

[0164] When the surface treatment is carried out using two different silane surface treatment agents, the polymeric silane surface treatment agent is typically used in a higher amount by weight compared to the non-polymeric silane surface treatment agent.

[0165] It has been found that ratios of polymeric silane surface treatment agent to non-polymeric silane surface treatment agent in the range of 90 / 10 to 60 / 40 or 80 / 20 to 70 / 30 by weight are useful.

[0166] If desired, the surfaces of the treated particles can be analyzed using FT-IR or NMR techniques.

[0167] The polymerizable silane surface treatment agent is typically an alkoxysilane, preferably a trialkoxysilane containing a (meth)acrylate group.

[0168] An exemplary embodiment is a compound of the formula: A m BSi(R 1 ) n (OR 2 ) 3-n wherein A comprises a (meth)acrylic moiety; B is (i) a linear or branched C1-C12 Alkyl, (ii) C6-C 12 aryl; (iii) a spacer group such as an organic group having 2 to 20 carbon atoms bonded together by one or more ether, thioether, ester, thioester, thiocarbonyl, amide, urethane, carbonyl, and / or sulfonyl bonds; R 1 is an alkyl group (e.g., C1 to C6) or an aryl group (e.g., C6 to C 12 ), R 2 contains an alkyl group (e.g., C1-C6), m=1, 2 or 3, and n=0, 1 or 2.

[0169] Examples of (meth)acrylate functionalized trialkoxysilanes include 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)-acryl-oxy-propyltris(methoxyethoxy)silane, 3-(meth)acryl-oxy-propenyltrimethoxysilane, (meth)-acryl-oxy-ethyldimethyl(3-trimethoxysilylpropyl)ammonium chloride, N-(3-(meth)acryloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane, O-((meth)acryloxyethyl)-N-(triethoxysilylpropyl)-urethane, (meth)acryloxy-methyltrimethoxysilane, (meth)acryloxymethyltriethoxysilane, (meth)acryloxymethylmethyldimethoxysilane, (meth)acryloxymethylmethyldiethoxysilane, Examples include, but are not limited to, (meth)acryloxyoctyltrimethoxysilane, [(meth)acryl-oxymethyl]phenethyltrimethoxysilane, O-[(meth)acryloxyethyl]-N-(triethoxysilyl-propyl)-carbamate, (meth)acryloxypropyltriisopropoxy-silane, (meth)acryloxypropylmethyldimethoxy-silane, (meth)acryloxypropylmethyldiethoxysilane, 3-(meth)acryloxypropyldimethylmethoxysilane, 3-(meth)acryloxypropyldimethylethoxysilane, (meth)acryloxymethyldimethylmethoxysilane, (meth)acryl-oxymethyldimethyl-ethoxysilane, oligomeric hydrolysate of 3-(meth)acryloxypropyltrimethoxy-silane, and oligomeric hydrolysate of 3-(meth)acryloxypropyltriethoxysilane.

[0170] The non-polymerizable silane surface treatment agent is typically an alkoxysilane, preferably a trialkoxysilane.

[0171] An exemplary embodiment is a compound of the formula: DSi(R 1 ) n (OR 2 ) 3-n wherein D is (i) a linear or branched, unsubstituted or substituted (e.g., with one or more amino or mercapto groups) C1-C 16 alkyl, (ii) unsubstituted or substituted (e.g., with one or more amino or mercapto groups) C-C 12 an aryl group, or (iii) an organic group having 2 to 20 carbon atoms bonded to each other by one or more ether, thioether, ester, thioester, thiocarbonyl, amide, urethane, carbonyl, and / or sulfonyl bonds; R 1 is an alkyl group (e.g., C1 to C6) or an aryl group (e.g., C6 to C 12 ), R 2 contains an alkyl group (e.g., C1-C6), n=0, 1 or 2].

[0172] Suitable non-polymeric silane surface treatment agents include phenyltrimethoxysilane, phenyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, hexadecyltrimethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, propyltrimethoxysilane, 3-aminopropyl-methyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercapto-propyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-cyclohexyl-3-aminopropyltrimethoxysilane, 3-ureido-propyl-trimethoxysilane, (cyclohexyl)methyldimethoxysilane, and mixtures thereof.

[0173] Polymeric and non-polymeric silane surface treatments are commercially available, for example, from Wacker (Munchen, Germany) under the product name Geniosil™ or from Evonik (Hanau, Germany) under the product name Dynasylan™.

[0174] The process for surface treating discrete nano-sized filler particles typically involves the following steps: mixing the sol containing nano-sized particles with a silane surface treatment agent; stirring the mixture under reflux in a solvent such as ethanol for several hours (e.g., 2 hours to 10 hours); After stirring for several hours (e.g., 2 to 10 hours), a step of again stirring for several hours (e.g., 2 to 10 hours) while mixing a monomer into the resulting mixture; and removing the solvent under vacuum.

[0175] A suitable process is also described in US Pat. No. 6,899,948 (Zhang et al.).

[0176] When filler(s) are present, in particular nanosized filler particles, they are typically present in the following amounts: at least 10, or at least 15, or at least 20 wt. %; or up to 70, or up to 60, or up to 50 wt. %; or from 10 to 70, or from 15 to 60, or from 20 to 50 wt. %, where the wt. % is based on the curable composition.

[0177] The use of such amounts of filler typically contributes to the physical-mechanical properties of the composition, particularly in its cured state.

[0178] The curable composition typically also includes one or more additives.

[0179] Additives that may be present include stabilizers, fluorescent dyes, UV light absorbers, fluoride releasers and mixtures thereof.

[0180] Suitable stabilizers include free radical scavengers, such as substituted and / or unsubstituted hydroxyaromatic compounds (e.g., butylated hydroxytoluene (BHT), hydroquinone, hydroquinone monomethyl ether (MEHQ), 3,5-di-tert-butyl-4-hydroxyanisole (2,6-di-tert-butyl-4-ethoxy-phenol), 2,6-di-tert-butyl-4-(dimethyl-amino)methylphenol or 2,5-di-tert-butylhydroquinone, 2-(2'-hydroxy-5'-methylphenyl)-2H-benzotriazole, 2-(2'-hydroxy 2-(2'-hydroxy-4',6'-di-tert-pentylphenyl)-2H-benzotriazole, 2-hydroxy-4-n-octoxybenzophenone, 2-(2'-hydroxy-5'-methacryloxyethylphenyl)-2H-benzotriazole, phenothiazine, and HALS (hindered amine light stabilizers).

[0181] Suitable fluorescent dyes often contain an anthracene or perylene moiety. Fluorescent dyes typically have an absorption peak in the range of 350 nm to 450 nm. Commercially available fluorescent dyes include, for example, Lumilux™ Blau LZ, Lumilux™ Gelb LZ, and dyes containing an anthracene moiety (e.g., 2-ethyl-9,10-dimethoxyanthracene; EDMO).

[0182] If present, the fluorescent dye is typically present in an amount of from 0.001% to 0.5% by weight based on the weight of the composition.

[0183] Suitable UV light absorbers include compounds containing a benzotriazole moiety. UV absorbers typically have an absorption peak in the range of 350 nm to 420 nm. Commercially available UV light absorbers include Tinuvin™ 326, Tinuvin™ 328, Tinuvin™ P, and Uvinul™ M40.

[0184] If present, UV light absorbers are typically present in an amount of from 0.001% to 1.0% by weight based on the weight of the composition.

[0185] Examples of fluoride-releasing agents include naturally occurring or synthetic fluoride minerals. These fluoride sources can optionally be treated with a surface treatment agent.

[0186] The additives are typically present in the following amounts: at least 0, or at least 0.01, or at least 0.1 wt. %; or up to 10, or 7.5, or 5 wt. %; or from 0 to 10, or 0.01 to 7.5, or 0.1 wt. % to 5 wt. %, where the wt. % is based on the curable composition.

[0187] The curable compositions described herein typically comprise: Radiation curable component(s): 20% to 95% by weight, Photoinitiator, optionally in combination with an activator: 0.01% to 5% by weight Filler: 0% to 70% by weight, Additives: 0% to 10% by weight, Contains each ingredient in the amount of The weight percentages are of the curable composition, the components being as described herein.

[0188] The curable composition also comprises: Methacrylate not containing a urethane moiety: 20% by weight to 75% by weight, Urethane (meth)acrylate: 5% by weight to 30% by weight, Photoinitiator, optionally in combination with an activator: 0.01% to 5% by weight; Filler: 10% by weight to 60% by weight, Additives: 0.01% by weight to 7.5% by weight, The composition may comprise, consist essentially of, or consist of each component in an amount of The weight percentages are of the curable composition, the components being as described herein.

[0189] The curable composition also comprises: Methacrylate not containing urethane moiety: 30% by weight to 65% by weight, Urethane (meth)acrylate: 10% by weight to 20% by weight, Photoinitiator, optionally in combination with an activator: 0.02% to 4% by weight Filler: 15% to 50% by weight, Additives: 0.1% by weight to 5% by weight, and The weight percentages are of the curable composition, the components being as described herein.

[0190] A more specific embodiment is described below.

[0191] Embodiment 1 1. A hardenable composition for use in a process of treating a dental condition in a patient's oral cavity, comprising: The curable composition comprises: radiation-curable component(s) selected from (meth)acrylate components, urethane (meth)acrylate components, and mixtures thereof; photoinitiator(s) selected from a component containing a phenyl-1,2-propanedione moiety, a component containing a benzyl moiety, bis(cyclopentadienyl)bis[2,6-difluoro-3-(1-pyrryl)phenyltitanium], and mixtures thereof; Optionally, filler(s); optionally comprising, consisting essentially of, or consisting of additive(s); The process is additively manufacturing a dental or orthodontic article layer-by-layer using radiation having a wavelength in the UV light range; attaching the dental or orthodontic article to a surface of dental hard tissue or dental material; applying radiation having a wavelength in the visible light range to the dental or orthodontic article.

[0192] Embodiment 2 1. A hardenable composition for use in a process of treating a dental condition in a patient's oral cavity, comprising: The curable composition comprises: a radiation-curable component(s) selected from a (meth)acrylate component, a urethane (meth)acrylate component, and mixtures thereof, in an amount of 20% to 95% by weight; photoinitiator(s) selected from a component containing a phenyl-1,2-propanedione moiety, a component containing a benzyl moiety, bis(cyclopentadienyl)bis[2,6-difluoro-3-(1-pyrryl)phenyltitanium, and mixtures thereof; optionally in combination with an activator, Filler(s) in an amount of 1% to 70% by weight; and The process is additively manufacturing a dental or orthodontic article layer-by-layer using radiation having a wavelength in the UV light range; attaching a dental or orthodontic article to a dental hard tissue surface; applying radiation having a wavelength in the visible light range to the dental or orthodontic article.

[0193] The weight percent is based on the curable composition.

[0194] Embodiment 3 1. A hardenable composition for use in a process of treating a dental condition in a patient's oral cavity, the hardenable composition comprising: a radiation-curable component(s) selected from a (meth)acrylate component, a urethane (meth)acrylate component, and mixtures thereof, in an amount of 20% to 75% by weight; photoinitiator(s) selected from a component containing a phenyl-1,2-propanedione moiety, a component containing a benzyl moiety, bis(cyclopentadienyl)bis[2,6-difluoro-3-(1-pyrryl)phenyltitanium, and mixtures thereof; optionally in combination with an activator, Filler(s) in an amount of 10% to 50% by weight; and The process is additively manufacturing a dental or orthodontic article layer-by-layer using radiation having a wavelength in the UV light range; applying a dental adhesive or dental cement to a surface portion of the dental or orthodontic article intended to be attached to dental hard tissue; attaching a dental or orthodontic article to a dental hard tissue surface; applying radiation having a wavelength in the visible light range to the dental or orthodontic article; The weight percent is based on the curable composition.

[0195] Embodiment 4 1. A hardenable composition for use in a process of treating a dental condition in a patient's oral cavity, the hardenable composition comprising: a radiation-curable component(s) selected from a (meth)acrylate component, a urethane (meth)acrylate component, and mixtures thereof, in an amount of 20% to 75% by weight; and a photoinitiator(s) selected from components comprising a phenyl-1,2-propanedione moiety. optionally in combination with an activator, Filler(s) in an amount of 10% to 50% by weight; and The process is additively manufacturing a dental or orthodontic article layer-by-layer using radiation having a wavelength in the UV light range; applying a dental adhesive or dental cement to a surface portion of the dental or orthodontic article intended to be attached to dental hard tissue; attaching a dental or orthodontic article to a dental hard tissue surface; applying radiation having a wavelength in the visible light range to the dental or orthodontic article; The weight percent is based on the curable composition.

[0196] The curable compositions described herein can be prepared by mixing the components together under reduced light conditions. If desired, a speed mixer can be used.

[0197] During storage, the curable compositions described herein are typically stored under reduced light conditions, especially in sealed containers, vessels, or foil bags. The volume of the container can range from 1 ml to 10 liters, or from 5 ml to 5 liters, or from 100 ml to 2 liters.

[0198] The curable composition can be processed in an additive manufacturing process to produce 3D printed articles. 3D printing processes are generally known to those skilled in the art.

[0199] An example of this type of technology is described in US Pat. No. 8,003,040 (B2) (El-Siblani), which relates to a process for producing three-dimensional objects by solidifying layers using synergistically stimulating electromagnetic radiation in a pattern.

[0200] In particular, the so-called SLA or DLP 3D printing processes have proven useful. Usable technical equipment is commercially available from companies such as, for example, 3Shape, Rapid Shape, Formlabs, Lithoz, Prodways, Stratasys, EnvisionTec, etc.

[0201] Additive manufacturing machines typically operate at specific radiation wavelengths in the range of 350 nm to 500 nm.

[0202] Additive manufacturing machines can also be characterized by the resolution they can achieve, with suitable resolutions typically in the range of 5 μm to 100 μm, or 10 μm to 80 μm, or 20 μm to 60 μm.

[0203] After the additive manufacturing process, the printed article can be post-processed if desired.

[0204] Useful post-processing steps include washing and optionally post-curing the washed article.

[0205] Cleaning of the 3D printed article can be done by using a cleaning solution and / or by performing a so-called spin cleaning process.

[0206] A cleaning process can be performed to remove any unwanted residue of curable resin remaining on the surface of the 3D printed article.

[0207] Suitable cleaning solutions include alcohols such as ethanol or isopropanol, esters of carboxylic acids such as dibasic esters of carboxylic acids and / or tribasic esters of carboxylic acids, or mixtures thereof. Suitable cleaning solutions are also described in WO 2018 / 222395 A1 (3M).

[0208] The spin cleaning process involves moving or rotating the three-dimensional article, which generates mass inertial forces.

[0209] The term "mass inertia force" referred to herein may be specified as force per unit mass, and therefore has the units m / s 2 The mass inertia force can also be expressed as G-force, which is a factor of the gravitational acceleration. In this specification, the gravitational acceleration is 9.81 m / s 2 Therefore, for example, 9.81 m / s 2 The mass inertia force can be expressed as 1G.

[0210] Acceleration forces or mass inertia forces are induced by moving, for example rotating, an object.

[0211] The centrifugal force on a particle on the surface of a three-dimensional article typically depends on the speed of rotation and the radius at which the particle is located from the axis of rotation.

[0212] By varying parameters such as the speed of the movement or rotation, its duration and / or the axis of rotation, this technique allows for the adjustment of the amount and layer thickness of the radiation curable composition remaining on the surface of the three-dimensional article.

[0213] In one embodiment, the mass inertia corresponds to a g-force of at least 100 g. A mass inertia of 100 g has proven suitable for removing medium to high viscosity radiation-curable materials. Those skilled in the art will recognize that the mass inertia required for cleaning may be lower for low viscosity materials and higher for high viscosity materials. Such methods are described, for example, in WO 2019 / 023120 A1 (3M).

[0214] Commercially available 3D printing equipment can be used to additively manufacture the dental or orthodontic articles described herein.

[0215] The use of the photoinitiators described herein is particularly advantageous in the following applications: layer thickness: 10 μm to 50 μm; curing light wavelength: 350 nm to 420 nm; curing light intensity: 5 W / m 2 ~100W / m 2 Radiation exposure time: 1 to 20 seconds When these processing parameters are applied, the radiation curable composition is cured.

[0216] After the additive manufacturing process is performed, a pre-cured dental or orthodontic article is obtained. Because no post-cure step has been applied, the pre-cured article typically still contains non-polymerized unsaturated moieties, such as (meth)acrylate moieties, on its surface.

[0217] If desired, the presence and optional amount of non-polymerized (meth)acrylate functionality can be characterized by determining the degree of conversion, or alternatively by IR spectroscopy (eg, Raman spectroscopy).

[0218] Pre-cured dental or orthodontic articles typically: a) be elastomeric; and b) have an elongation at break in the range of 10% to 200%, as determined according to DIN EN ISO 527-1:2012-06. may be characterized by the features listed above alone or in combination.

[0219] The hardened dental or orthodontic article typically has: a) a flexural strength in the range of 60 MPa to 200 MPa, as measured according to ISO / DIN 4049 (2019); b) an elongation at break in the range of 1% to 40%, as determined according to DIN EN ISO 527-1:2012-06. may be characterized by the features listed above alone or in combination.

[0220] The dental or orthodontic article may have different shapes either before or after hardening. The volume of the dental or orthodontic article is typically in the range of 0.1 ml to 10 ml or 0.2 ml to 5 ml.

[0221] For example, the dental article may have the shape of a dental crown, a dental bridge, a dental onlay, a dental inlay, or a dental veneer.

[0222] The hardenable compositions described herein are particularly useful for producing dental articles having the shape of a crown, particularly dental articles having the shape of a crown for pediatric use.

[0223] These types of dental composite crowns are described, for example, in U.S. Pat. No. 10,610,330 (B2) (Herrmann et al.) or U.S. Patent Application Publication No. 2020 / 0206092 (A1) (Herrmann et al.), the contents of which are incorporated herein by reference.

[0224] Dental composite crowns obtained by processing the hardenable compositions herein in an additive manufacturing process are typically ductile and can be shaped or conformed by a practitioner, if desired, before or during the step of attaching the dental composite crown to the surface of a tooth stump in a patient's mouth.

[0225] Additionally, due to its resilient properties, the preformed dental composite crown can be easily placed over the stump of a tooth, even when an undercut is present.

[0226] A final curing or hardening step of the dental composite crown can then be performed using a dental curing light having a wavelength in the visible light range, for example, after the dental composite crown has been placed over the stump in the patient's mouth.

[0227] This provides the practitioner with more flexibility.

[0228] The orthodontic article may have the shape of an orthodontic attachment, an orthodontic bracket.

[0229] Orthodontic articles that can be produced by using the hardenable compositions described herein are described, for example, in WO 2021 / 130624(A1) (3M), WO 2022 / 149083 (3M), or WO 2022 / 149084(A1) (3M), the contents of which are incorporated herein by reference.

[0230] The present invention also relates to a kit of parts.

[0231] The kit of parts comprises, consists essentially of, or consists of a hardenable composition described herein, a dental adhesive, dental cement, or dental primer, optionally a curing light, optionally a dental positioning tray, and optionally instructions for use.

[0232] Dental adhesives typically have a fairly low viscosity (e.g., 0.01 Pa at 23°C). * s~3Pa * The dental adhesive is an acidic dental composition having an acidic acid group (a component of the dental adhesive) and an ethylenically unsaturated component (a component of the dental adhesive) that interacts directly with the tooth enamel or dentin surface. The dental adhesive is typically a one-part composition that is radiation-curable and includes an ethylenically unsaturated component(s) that has an acidic moiety, an ethylenically unsaturated component(s) that does not have an acidic moiety, water, a sensitizer(s), a reducing agent(s), and an additive(s).

[0233] Examples of dental adhesives are described in U.S. Patent Application Publication Nos. 2020 / 0069532(A1) (Thalacker et al.) and 2017 / 0065495(A1) (Eckert et al.). Dental adhesives are also commercially available, such as 3M™ Scotchbond™ Universal or 3M™ Scotchbond™ Universal Plus (3M Oral Care).

[0234] Suitable dental primers are described in U.S. Patent No. 6,126,922 (Rozzi et al.) and WO 00 / 69393(A1) (3M). Dental primers are also commercially available (e.g., 3M™ Transbond™ XT Primer (3M Oral Care)).

[0235] Dental cements that can be added to the kit include, among others, self-adhesive resin cements that contain an acidic polymerizable component (e.g., a (meth)acrylate component with a phosphoric acid or carboxylic acid moiety), a polymerizable component without an acidic moiety, an initiator system, and a filler.

[0236] Suitable dental cements are also commercially available, for example RelyX™ Unicem 2, RelyX™ Universal or RelyX™ Luting Plus (3M Oral Care).

[0237] Dental positioning trays are typically used to place orthodontic attachments on a patient's teeth. Examples of dental positioning trays are described in U.S. Patent Application Publication No. 2015 / 0313687(A1) (Blees et al.) and U.S. Patent Application Publication No. 2020 / 131356(A1) (Zech et al.).

[0238] Suitable dental curing lights are described in U.S. Patent No. 10,758,126 (B2) (Geldmacher et al.) or U.S. Patent No. 10,231,810 (B2) (Gramann et al.). Dental curing lights are also commercially available (e.g., 3M™ Elipar™ S10 or 3M™ Elipar™ Deep-Cure S LED Curing Light (3M Oral Care)).

[0239] The instructions for use describe how the dental product or hardenable composition should be used in daily practice, outlining, for example, application steps and hardening conditions.

[0240] The hardenable composition is for use in the process of treating a dental condition in a patient's mouth.

[0241] As described above, a pre-hardened dental or orthodontic article, or a dental or orthodontic article including a pre-hardened composition, is first manufactured.

[0242] If desired, the pre-cured article can be post-treated, particularly washed.

[0243] The pre-cured article is then attached to the surface of dental hard tissue or another dental material. If desired, this process can be assisted by the use of a dental adhesive or dental cement.

[0244] Therefore, the process Optionally, post-processing the pre-cured dental or orthodontic article; applying a dental adhesive or dental cement to the surface portion of the dental or orthodontic article that is intended to be attached to the dental hard tissue or dental material.

[0245] In a further step, the pre-cured article is radiation cured, typically using wavelengths in the visible light range.

[0246] If the dental adhesive or dental cement is also radiation curable, the pre-cured dental or orthodontic article and radiation curing of the dental adhesive or dental cement can occur simultaneously.

[0247] More specifically, the preferred process comprises the following: a. processing the hardenable composition in an additive manufacturing process, optionally followed by post-processing steps such as washing, to obtain a 3D printed pre-cured orthodontic article; b. Inserting the 3D printed pre-cured orthodontic article into a cavity of a dental positioning tray; c. applying a dental adhesive or dental cement to the surface of the 3D printed pre-cured orthodontic article that is intended to be attached to the tooth surface; d. inserting a transparent dental positioning tray into the patient's mouth; e. radiation curing the 3D printed pre-cured orthodontic article; f. removing the dental positioning tray from the patient's oral cavity; g. Optionally, inserting a dental aligner tray into engagement with the orthodontic article.

[0248] For effective radiation curing of 3D printed pre-cured orthodontic articles, the dental positioning tray should be transparent to the light used for radiation curing.

[0249] Dental aligner trays are used to straighten teeth, much like braces. They use gentle, consistent force to move teeth into desired positions. They are typically clear and custom-made.

[0250] The process typically does not include the following additional steps: roughening the surface of the 3D printed dental or orthodontic article that is intended to be attached to dental hard tissue or dental material; and / or Applying a further radiation curing step to the pre-cured dental or orthodontic article before the article is attached to the dental hard tissue or dental material.

[0251] Roughening the surface of the pre-cured article to increase its size is not necessary because the pre-cured article contains a sufficiently large amount of polymerizable moieties that are available for copolymerization reactions with other (meth)acrylate components present, for example, in a dental adhesive or dental cement.

[0252] For the same reason, applying an additional radiation curing or post-curing step before the article is attached to dental hard tissue or another dental material is counterproductive, as the amount of polymerizable moiety is reduced.

[0253] Additionally, the radiation curable compositions herein typically comprise the following components: a) 0.1 or 0.3 wt. % or more of a peroxide component, based on the weight of the radiation-curable composition; b) (meth)acrylates having acidic moieties in an amount of 2% by weight or more; Not including, The weight percentages are based on the weight of the curable composition.

[0254] Thus, the radiation curable composition is essentially free of peroxide components or (meth)acrylates with acidic moieties, and does not contain intentionally added peroxide components or (meth)acrylates with acidic moieties.

[0255] The complete disclosures of the patents, patent documents, and publications cited herein are incorporated by reference in their entirety, as if each were individually incorporated. Various modifications and variations to the present invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. The above specification, examples, and data provide a description of the manufacture and use of the compositions and methods of the present invention. The present invention is not limited to the embodiments disclosed herein. Those skilled in the art will recognize that many alternative embodiments of the present invention can be made without departing from the spirit and scope of the present invention.

[0256] The following examples are presented to illustrate the present invention. [Example]

[0257] method viscosity If desired, the viscosity was adjusted to 0.1 s using a 25 mm plate / cone system with a Physica MCR 301 (Anton Paar Germany GmbH, Ostfildern-Scharnhausen). -1 ~1,000s -1 It can be measured at 23.0°C with a shear gradient of

[0258] Methods for determining optical absorption bands If desired, optical absorption spectra can be determined using a Spectramax 190 spectrophotometer (available from Molecular Devices LLC., Sunnyvale, CA, USA). A multi-cuvette, such as a Microtest 96-well 370 μl clear plate (available from BD Biosciences, Franklin Lakes, NJ, USA), is used. 200 μl of the solution (photoinitiator dissolved in TEGDMA) is placed in one of the 96 cuvettes and loaded into the Spectromax 190. Spectra are recorded between 200 nm and 800 nm in 1 nm increments.

[0259] Particle size distribution (non-nano-sized particles) If desired, particle size can be measured using a Malvern Mastersizer 2000 (Malvern Instruments, Malvern, Worcestershire, UK) light scattering device. The Mastersizer 2000 uses an integrated optical system to cover a range of 0.02 μm to 2000 μm. The mixture to be analyzed is added to a test chamber filled with isopropanol until approximately 8% to 15% obscuration is reached. Ultrasound is not applied to avoid altering the particle size distribution. The raw data is processed by the instrument software, which uses the refractive index of the non-nanosized filler and applies a Mie correction with the Fraunhofer approximation, a technique known to experts.

[0260] Particle size distribution (nano-sized particles) The measurement of the size of the nanoparticles is preferably based on TEM (Transmission Electron Microscopy) methods, by which the population is analyzed and the average particle size is obtained. A preferred method of particle size measurement can be described as follows: Approximately 80 nm thick samples are placed on 200 mesh copper grids (SPI Supplies, a division of Structure Probe, Inc., West Chester, PA) with carbon-stabilized Formvar substrates. Transmission electron micrographs (TEM) are taken at 200 KV using a JEOL200CX (JEOL Ltd., Akishima, Japan; sold by JEOL USA, Inc.). Population sizes of approximately 50-100 particles can be measured, and the average diameter determined.

[0261] Flexural strength (FS) If desired, the bending strength was measured according to ISO 4049 (2019) using a universal testing machine (Zwick Z 010, crosshead speed 2 mm / min) and size 2 * 2 * This can be done using 25 mm specimens. Flexural strength is typically given in MPa.

[0262] Elongation at break (EaB) If desired, the elongation at break of the material can be determined according to DIN EN ISO 527-1:2012-06. The elongation is given in % of the original length. The elongation data are as follows: central unit: 10 mm x 2 mm x 2 mm; total length: 25 mm; width of wider part: 5 mm; radius of rounded edge: R = 10 mm on the central unit; 25 mm on the wider part. The test piece can be evaluated on a Zwick Z010 universal testing machine by tearing at least three I-shaped specimens of dimensions 1.

[0263] material

[0264] [Table 1]

[0265] The light absorption characteristics of the photoinitiators are shown in Table 2.

[0266] [Table 2]

[0267] The resin compositions (RCx) shown in Table 3 were prepared:

[0268] [Table 3]

[0269] General Process for Making the Curable Composition The components are mixed under safe light conditions using a speed mixer, followed by a roll mill step, and the mixture is then vacuum treated in a laboratory kneader.

[0270] The general process for producing 3D printed objects Additive manufacturing process: The composition was poured into the work tray of a commercially available DLP printer (Rapidshape, Heimsheim, Germany). The pre-processed data (STL file; shape of a three-dimensional rectangular parallelepiped object; 25 mm * 2mm * Load a 2 mm (2 mm) of the adhesive into the printer. The following printing conditions can be applied: Curing light wavelength: 360 nm to 420 nm; Curing light intensity: 5 W / m 2 ~100W / m 2 ;Exposure time: 1 s to 11 s;Layer thickness: 25 μm.

[0271] three dimensional article The three-dimensional article can be produced as follows: The composition is placed in the vat of an additive manufacturing machine. The three-dimensional article is produced layer by layer by using the parameters described above in the additive manufacturing process. The three-dimensional article may have the shape of a test sample or an orthodontic article, as desired. The three-dimensional article is removed from the vat of the additive manufacturing machine.

[0272] Cleaning process: Cleaning of the three-dimensional article from excess material can be carried out using the parameters described in the text above, as described in WO 2019 / 023120 (A1) (3M).

[0273] Post-curing The post-cure step was performed using an Elipar™ Deep-Cure S dental curing light (3M Oral Care). This dental curing light provides light with a wavelength ranging from 430 nm to 480 nm. The following conditions were applied: 1470 mW / cm 2 For 60 seconds.

[0274] Testing (General Process) Using the formulations shown in Table 3, specimens (2 × 2 × 25 mm) for flexural strength (FS) testing were prepared via the additive manufacturing process described above, followed by a post-curing step. The results are provided in Table 4.

[0275] [Table 4]

[0276] The results in Table 4 show that TPO(CE1) can be used to obtain 3D printed specimens with flexural strengths of approximately 40 MPa.

[0277] Additional post-curing with visible light does not result in an increase in flexural strength.

[0278] Using a combination of TPO and camphorquinone (CE2), a flexural strength of approximately 30 MPa can be obtained after 3D printing, which increases to over 70 MPa after additional treatment with visible light.

[0279] In contrast, the use of PPD (IE1) leads to very flexible samples after 3D printing that cannot be broken by the testing machine (Figure 3) and therefore the bending strength cannot be determined.

[0280] By performing an additional photocuring step, the flexural strength increased to a value of approximately 80 MPa.

[0281] This clearly demonstrates that PPD can be used to 3D print polymerizable compositions into a highly flexible pre-cured state, allowing for manipulation and handling of the resulting article, as is possible with stainless steel crowns.

[0282] Additionally, the 3D printed article in its pre-cured state has sufficient (meth)acrylate linkages available to achieve good adhesion with a binder for 3D printing attachment, if desired.

[0283] Final curing (post-curing) can be achieved with visible light in the patient's mouth to ensure strength and durability.

Claims

1. 1. A hardenable composition for use in a process of treating a dental condition in a patient's oral cavity, comprising: The curable composition is radiation-curable component(s); photoinitiator(s) alone, which exhibits absorption in the UV light region and absorption in the visible light region, said absorption at 390 nm being stronger than said absorption at 450 nm; Optionally, filler(s); and optionally additive(s), The process comprises: additively manufacturing a dental or orthodontic article layer-by-layer using radiation having a wavelength in the UV light range; attaching the dental or orthodontic article to a surface of dental hard tissue or dental material; applying radiation having a wavelength in the visible light range to said dental or orthodontic article; the UV light region is defined as light having a wavelength in the range of 350 nm to 410 nm; A curable composition for use wherein said visible light region is defined as light having a wavelength in the range of 440 nm to 500 nm.

2. said photoinitiator(s) being containing a diketone moiety, and / or 10. The curable composition for use according to claim 1, which is non-fluorescent.

3. 3. The curable composition for use according to claim 1 or 2, wherein the photoinitiator(s) are selected from components comprising a phenyl-1,2-propanedione moiety, components comprising a benzyl moiety, bis(cyclopentadienyl)bis[2,6-difluoro-3-(1-pyrryl)phenyltitanium], monoacyl or diacylgermanium moiety, and mixtures thereof.

4. A curable composition for use according to any one of claims 1 to 3, wherein said curable composition comprises only one photoinitiator, optionally in combination with an activator.

5. <50 Pa at 23°C ＊ Viscosity of 1 s and 1 s －１ 5. The curable composition for use according to any one of claims 1 to 4, characterized by a shear rate of

6. The curable composition for use according to any one of claims 1 to 5, wherein the radiation curable component is selected from a (meth)acrylate component, a urethane (meth)acrylate component and mixtures thereof.

7. The curable composition for use according to any one of claims 1 to 6, wherein said filler(s) comprise nano-sized filler particles.

8. below: Radiation curable component: 20% to 95% by weight, Photoinitiator(s), optionally in combination with an activator: 0.01% to 5% by weight; Filler(s): 0% to 70% by weight, Additives: 0% to 10% by weight 8. A curable composition for use according to any one of claims 1 to 7, comprising the components in an amount of

9. below: 30% to 65% by weight of methacrylate not containing a urethane moiety, Urethane (meth)acrylate: 10% by weight to 20% by weight, Photoinitiator(s), optionally in combination with an activator: 0.02% to 4% by weight; Filler(s): 15% to 50% by weight, Additive(s): Contains ingredients in an amount of 0.1% to 5% by weight; A curable composition for use according to any one of claims 1 to 8, wherein the weight percentages are based on the curable composition.

10. below: 30% to 65% by weight of methacrylate not containing a urethane moiety, Urethane (meth)acrylate: 10% by weight to 20% by weight, Photoinitiator(s), optionally in combination with an activator: 0.02% to 4% by weight; Filler(s) comprising nano-sized filler particles having an average particle size of 40 nm or less: 15% to 50% by weight; Additive(s): Contains ingredients in an amount of 0.1% to 5% by weight; A curable composition for use according to any one of claims 1 to 9, wherein the weight percentages are based on the curable composition.

11. the dental or orthodontic article having a surface portion for attachment to a surface of dental hard tissue or dental material; The process comprises: Optionally, post-processing the pre-hardened dental or orthodontic article; 11. The hardenable composition for use according to any one of claims 1 to 10, comprising the additional step of: applying a dental adhesive or dental cement to the surface portion of the dental or orthodontic article that is intended to be attached to dental hard tissue or dental material.

12. The process comprises: roughening the surface portion of the dental or orthodontic article intended to be attached to dental hard tissue or dental material; and / or 12. The hardenable composition for use according to any one of claims 1 to 11, which does not comprise the additional step of applying a further radiation curing step to the dental or orthodontic article before the dental or orthodontic article is attached to the dental hard tissue or to the dental material.

13. A kit of parts comprising a hardenable composition for use according to any one of claims 1 to 10, a dental adhesive or dental cement, optionally a dental positioning tray, and optionally instructions for use.

14. 13. A pre-hardened composition obtainable by processing the hardenable composition for use according to any one of claims 1 to 12 in an additive manufacturing process, the pre-hardened composition having the shape of a dental or orthodontic article.

15. below: be rubber elastic; having an elongation at break in the range of 10% to 200%, as determined according to DIN EN ISO 527-1:2012-06; 15. The pre-cured composition of claim 14, characterized by the following features, either alone or in combination:

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