Auxiliary instrument for dental treatment, photocurable composition, and method for producing auxiliary instrument for dental treatment

Abstract

The present invention addresses the problem of providing an auxiliary instrument for dental treatment capable of being easily removed from a tooth restored while hardly causing pain to a patient when removing the auxiliary instrument for dental treatment after curing a curable composition for tooth restoration. One aspect for solving the above problem is an auxiliary instrument for dental treatment, the auxiliary instrument having a body part having a recessed opening part capable of accommodating at least a portion required to be restored of a tooth restored of a patient, wherein: a portion at least accommodating the portion required to be restored has an inner surface shape corresponding to a preliminarily designed outer surface shape of the portion required to be restored of the tooth after restoration; in a state in which the body part is elastically deformed and attached to the tooth restored, a cavity is formed by the inner surface shape and the outer surface shape of the tooth restored; the auxiliary instrument for dental treatment restores the tooth restored by irradiating a dental photocurable composition introduced into the cavity with light in a state of being attached to the tooth restored to cure the dental photocurable composition; and a resin material having a tensile elongation in accordance with JIS K6251 of 10%-60% is used.

Description

Dental treatment auxiliary instrument, photocurable composition, and method for manufacturing dental treatment auxiliary instrument

[0001] The present invention relates to a dental treatment auxiliary instrument, a photocurable composition, and a method for producing a dental treatment auxiliary instrument.

[0002] In dental treatment, a method is known in which a hardenable composition is filled into a ground-out portion of dental tissue, and then hardened while a mold (dental treatment auxiliary instrument) having a specific shape is brought into contact with the hardenable composition, thereby obtaining a hardened product with a desired shape (see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2019-107247

[0004] The dental treatment auxiliary instrument is also called a clear index and is made of a resin material. The resin material is required to have physical properties such as translucency for hardening the hardenable composition, an elastic modulus for returning to a designed shape after being deformed when attached to the tooth to be restored, an elastic deformation power for keeping the time required for returning to the shape within a practical range, and hardness that does not cause pain to the patient. However, depending on the type of restoration, there are problems in that removing the dental treatment auxiliary instrument can cause pain to the patient or damage to the restored area.

[0005] The present disclosure has been made in view of the above-mentioned problems, and aims to provide a dental treatment auxiliary instrument that can be easily removed from a tooth to be repaired without causing pain to the patient when removing the dental treatment auxiliary instrument after hardening a hardenable composition for tooth restoration.

[0006] (1) A dental treatment auxiliary instrument that is a molded body of an elastically deformable and translucent resin material, the dental treatment auxiliary instrument having a cap-shaped main body with an open recess capable of accommodating at least a portion of a patient's tooth to be restored, the portion accommodating at least the portion to be restored having an inner surface shape corresponding to a pre-designed outer surface shape of the tooth after the portion to be restored has been restored, the outer surface of the portion to be restored and the inner surface shape form a cavity when the main body is elastically deformed and attached to the tooth to be restored, the dental treatment auxiliary instrument is attached to the tooth to be restored by irradiating light to a dental photocurable composition introduced into the cavity to harden the dental photocurable composition, and the dental treatment auxiliary instrument has a tensile elongation of 10 to 60% in accordance with JIS K 6251.

[0007] (2) The dental treatment auxiliary instrument according to (1), wherein the resin material has a durometer hardness of 60 to 89 in accordance with JIS K 6253, and the resin material has an elastic deformation power of 70 to 100% when the elastic deformation power (%) is calculated using the formula 100 × {We / (Wp+We)} based on the elastic deformation power We (unit: kgf m / s) and the plastic deformation power Wp (unit: kgf m / s) determined by a compression test using a cylindrical test piece having a diameter of 9.0 mm and a height of 13.0 mm in accordance with Method C of JIS K 6254.

[0008] (3) The dental treatment auxiliary instrument according to (1) or (2), wherein the opening recess in the main body has a small piece for gripping and / or a notch for tearing at an outer periphery of the opening.

[0009] (4) A polymerizable composition comprising a urethane diacrylate or urethane dimethacrylate (A) having a weight average molecular weight of 1,000 to 20,000, a non-urethane monofunctional polymerizable monomer (B1) consisting of a monoacrylate or monomethacrylate having a weight average molecular weight of 80 to 1,000 and having neither a urethane bond nor an amide group in the molecule, and a non-urethane bifunctional polymerizable monomer (B2) consisting of a diacrylate or dimethacrylate having a weight average molecular weight of 500 to 2,000 and having neither a urethane bond nor an amide group in the molecule. and a photopolymerization initiator, wherein the content of (A) in the polymerizable component is 40 to 95 mass %, and the ratio of the total amount of polymerizable groups: n (mmol) to the total mass of the polymerizable component: W (g), where W is the total mass of the polymerizable component and n is the total amount of polymerizable groups of bifunctional or higher functional polymerizable monomers contained in the polymerizable component, is n / W (mmol / g), which is 0.3 to 3.0 (mmol / g).

[0010] (5) The photocurable composition according to (4), which contains the non-urethane bifunctional polymerizable monomer (B2).

[0011] (6) The photocurable composition according to (4), which is used for producing the resin material in the dental treatment auxiliary instrument according to any one of (1) to (3).

[0012] (7) A method for manufacturing a dental treatment auxiliary instrument described in (1), comprising: digitizing and ranking the height direction of the main body portion from three-dimensional shape data representing the shape of the main body portion, and generating two-dimensional shape data representing the cross-sectional shape of the main body portion at each ranked height; irradiating a liquid photocurable composition held in a tank with activation light at a predetermined position determined in advance based on the two-dimensional shape data, thereby selectively curing the liquid photocurable composition present at that position to form a modeling layer having the cross-sectional shape; and sequentially forming and stacking modeling layers having the cross-sectional shape at each height in accordance with the ranking order, thereby obtaining a laminate having a shape corresponding to the shape of the main body portion; and a manufacturing method for a dental treatment auxiliary instrument, comprising: a molding process using the photocurable composition described in (4) or (5) as the liquid photocurable composition.

[0013] According to the present invention, it is possible to provide a dental treatment auxiliary instrument that can be easily removed from a tooth to be restored without causing pain to the patient when removing the dental treatment auxiliary instrument after hardening a hardenable composition for tooth restoration.

[0014] 1 is a diagram showing the shape of a dental treatment auxiliary instrument according to one embodiment of the present disclosure. FIG. 2 is a perspective view of FIG. 1 seen from another viewpoint, showing a state when the dental treatment auxiliary instrument is detached from the tooth to be repaired by using a small pinch. FIG. 3 is a diagram showing the shape of a dental treatment auxiliary instrument according to another embodiment of the present disclosure.

[0015] As described above, the inventors have noticed that dental treatment auxiliary instruments have the problem that, when removing the dental treatment auxiliary instrument after repairing the portion requiring restoration of the tooth to be restored, the instrument may impose a burden on the patient or the restored portion may be damaged. As a result of investigations conducted by the inventors to solve the above problem, they have found that the above problem can be solved by setting the tensile strength of the resin material constituting the main body of the dental treatment auxiliary instrument within a predetermined range. Specifically, they have found that, when a certain amount of stress is concentrated in a narrow region of the main body having a predetermined tensile strength, the main body is torn starting from that region, making it easier to remove the dental treatment auxiliary instrument, and have completed the invention of the present disclosure.

[0016] The dental treatment auxiliary instrument, photocurable composition, and method for producing the dental treatment auxiliary instrument of the present disclosure will be described below.

[0017] 1. Dental Treatment Auxiliary Instrument The dental treatment auxiliary instrument of the present disclosure is used in direct bonding treatment using a light-curable composition called composite resin, i.e., to repair or be used for repairing a patient's teeth (tooth to be repaired), such as teeth damaged by caries or fractures, teeth forming a gap in the dentition, or teeth adjacent to a missing tooth, to restore them to a target tooth shape.

[0018] 1 and 2 are diagrams illustrating how to use the dental treatment auxiliary instrument 1 (Clear Index). The dental treatment auxiliary instrument 1 is attached to and used by placing it over the crown of a tooth to be restored in the dentition before restoration. The crown of the tooth before restoration has a cavity (a portion to be restored: a hole drilled after removing a tooth missing due to caries or the like). That is, the main body of the dental treatment auxiliary instrument 1 has a cap-like shape with an open recess that can accommodate at least the portion to be restored. The portion of the dental treatment auxiliary instrument 1 that accommodates the cavity has an inner surface shape that corresponds to the outer surface shape of the tooth after restoration of the portion to be restored, which has been designed in advance.

[0019] In dental treatment using the dental treatment auxiliary instrument 1, first, the dental treatment auxiliary instrument 1 is elastically deformed and placed over the crown of the tooth to be restored (an anterior tooth in FIGS. 1 and 2 ). This forms a cavity between the outer surface of the area to be restored and the inner surface of the dental treatment auxiliary instrument 1. Next, the cavity is filled with a composite resin (a photocurable composition for tooth restoration). Note that FIG. 3 , which illustrates another embodiment described below, shows the state in which the composite resin is being filled into the cavity using a syringe. The main body of the dental treatment auxiliary instrument 1 may be formed with a hole for inserting the tip of a syringe used to fill the composite resin, as well as holes for venting air and / or discharging excess composite resin. Alternatively, a method may be used in which the composite resin is first placed in the area to be restored and then the dental treatment auxiliary instrument 1 is placed over the crown of the tooth to be restored, thereby filling the cavity with the composite resin. In this case, it is not always necessary to form a hole in the main body.

[0020] With the composite resin filled in the cavity, light is irradiated onto the composite resin from the outside of the dental treatment auxiliary instrument 1 to harden it. This restores the tooth to the target tooth shape. Note that in this specification, restoration to the target tooth shape is not limited to sealing the cavity, but also includes adjusting the shape of a crown, significantly increasing the size of a crown that is smaller than a predetermined size, and forming a new crown in a location where no crown originally existed (a missing portion) by using an adjacent tooth (direct bonding bridge).

[0021] After the composite resin is hardened in the cavity, the dental treatment auxiliary instrument 1 is removed from the tooth to be restored. At this time, the dental treatment auxiliary instrument 1 may be torn or otherwise at least partially damaged before being removed. This makes it possible to reduce the pain felt by the patient when the dental treatment auxiliary instrument 1 is removed.

[0022] In addition to the cap-shaped main body portion having an open recess, the dental treatment auxiliary instrument 1 preferably includes a gripping piece 2 shown in FIGS. 1 and 2 . The gripping piece 2 is provided, for example, on the outer periphery of the open recess. When removing the dental treatment auxiliary instrument 1, the therapist of the tooth to be restored can easily remove the dental treatment auxiliary instrument 1 by grasping the gripping piece 2. Furthermore, by gripping the gripping piece 2 and applying force, stress tends to concentrate in a narrow area. As a result, the main body portion is torn starting from that area, allowing the dental treatment auxiliary instrument 1 to be easily removed from the tooth to be restored. The gripping piece 2 is, for example, formed integrally with the main body portion of the dental treatment auxiliary instrument 1. The gripping piece 2 may be made of the same material as the main body portion, or may be made of a different material, or may be joined to the main body portion.

[0023] The dental treatment auxiliary instrument 1 may have a tear notch (not shown) formed on the periphery of the opening recess. This makes it easier to tear the main body portion starting from the tear notch. The shape of the tear notch is not particularly limited, and any shape can be used, such as a V-shape, a U-shape, a hole-shape, a slit-shape, or a notch-shape. When the dental treatment auxiliary instrument 1 has a gripping piece 2, the tear notch is preferably formed near the gripping piece 2. This allows stress to be concentrated on the tear notch when the gripping piece 2 is grasped and force is applied, making it easier to tear the main body portion.

[0024] 1 and 2 illustrate a dental treatment auxiliary instrument 1 for a case in which the tooth to be restored is a front tooth, but the present disclosure is not limited to this. Fig. 3 illustrates a dental treatment auxiliary instrument 1a for a case in which the tooth to be restored is a back tooth. The dental treatment auxiliary instrument 1a has a small pinching piece 2a. The configuration of the dental treatment auxiliary instrument 1a is similar to the configuration of the dental treatment auxiliary instrument 1, except that the tooth to be restored is a back tooth.

[0025] The dental treatment auxiliary instrument of the present disclosure is composed of a molded body made of a translucent resin material. The resin material has a tensile elongation (elongation at break) of 10 to 60% in accordance with JIS K 6251. When the tensile elongation of the resin material is within the above range, the patient feels less pain when removing the dental treatment auxiliary instrument, and the dental treatment auxiliary instrument can be easily removed from the tooth to be restored. Specifically, when the tensile elongation of the dental treatment auxiliary instrument is 10% or more, the dental treatment auxiliary instrument can be attached to the tooth to be restored without breaking. When the tensile elongation of the dental treatment auxiliary instrument is 60% or less, the dental treatment auxiliary instrument can be easily removed from the tooth to be restored by tearing it with relatively little force without excessive stretching. From the above viewpoints, the tensile elongation of the resin material is preferably 20 to 50%.

[0026] The resin material preferably has a durometer hardness of 60 to 89 according to JIS K 6253. A durometer hardness of 89 or less can reduce pain felt by patients at the contact point between the dental treatment auxiliary instrument and the gums. Furthermore, a durometer hardness of 85 or less is more preferable because it can be deformed with a moderate force and placed in a treatment area with an undercut. If the resin material has a durometer hardness that is too low, the dental treatment auxiliary instrument may be easily deformed with only a slight force, potentially changing the shape of the restoration site. Therefore, a durometer hardness of 60 or more is preferable, and a durometer hardness of 70 or more is more preferable. Note that the durometer hardness in this specification refers to the apparent hardness measured using a Type A durometer defined in JIS K 6253. Durometer hardness is measured by contacting the indenter and pressure plate of a durometer with the test specimen.

[0027] The resin material preferably has an elastic deformation power of 70 to 100%. An elastic deformation power of 70% or more allows the dental treatment auxiliary device to quickly return to its designed shape after being attached to the tooth to be restored, thereby improving workability during treatment. The elastic deformation power is more preferably 80% or more, and even more preferably 90% or more. The elastic deformation power in this specification is a value calculated using the formula 100 × {We / (Wp + We)} based on the elastic deformation work: We (unit: kgf m / s) and the plastic deformation work: Wp (unit: kgf m / s) determined by a compression test using a cylindrical test piece with a diameter of 9.0 mm and a height of 13.0 mm, performed in accordance with Method C of JIS K 6254.

[0028] The above resin material can be preferably produced by curing a photocurable composition as described below.

[0029] 2. Photocurable Composition The photocurable composition of the present disclosure comprises a polymerizable component including a urethane di(meth)acrylate (A) and a non-urethane polymerizable monomer (B), and a photopolymerization initiator. In this specification, the term "(meth)acrylate" refers to both "acrylate" and "methacrylate." The term "(meth)acryloyl" refers to both "acryloyl" and "methacryloyl." The term "(meth)acrylic" refers to both "acrylic" and "methacrylic."

[0030] <Polymerizable Component> The weight average molecular weight of the urethane di(meth)acrylate (A) is 1,000 to 20,000. The urethane di(meth)acrylate (A) is not particularly limited as long as it has two (meth)acryloyl groups and a urethane bond in the molecule and has a molecular weight within the above range. The urethane di(meth)acrylate (A) is represented, for example, by the following formula (1):

[0031]

[0032] In formula (1), R １ and R ２ are each independently a hydrogen atom or a methyl group.

[0033] In formula (1), R ３ and R ４ each independently represents a substituted or unsubstituted alkyleneoxy group. Examples of the alkyleneoxy group include linear or branched alkyleneoxy groups, such as a methyleneoxy group, an ethyleneoxy group, a trimethyleneoxy group, a propyleneoxy group, and an n-butyleneoxy group.

[0034] In formula (1), a represents an integer of 0 or greater than 1. When there are multiple a's, the structures in parentheses following a may be the same or different.

[0035] R ５ When there are a plurality of "-"s, they may be the same or different and represent substituted or unsubstituted hydrocarbon groups. Examples of hydrocarbon groups include alkylene groups such as methylene, ethylene, propylene, isopropylene, butylene, hexylene, 2-ethylhexylene, nonylene, and cyclohexylene; arylene groups such as phenylene; and aralkylene groups such as xylylene. Examples of substituents that may substitute for the hydrocarbon group include halogens and alkoxy groups.

[0036] In formula (1), R ６ has a structure derived from a polyol represented by the following formula (1-1): In formula (1-1), X is R ５ represents a hydrocarbon group having the same meaning as —O—X— (1-1)

[0037] In formula (1), b is 0 or an integer of 1 or more. ７ has a structure derived from a polyol represented by formula (1-1).

[0038] In formula (1), c is 0 or an integer of 1 or more. ８ When there are a plurality of R, they may be the same or different. ８ represents a structure derived from a carboxylic acid represented by the following formula (1-2): In formula (1-2), Y is R ５ represents a hydrocarbon group having the same meaning as the above. -OOC-Y-COO- (1-2)

[0039] Such a urethane di(meth)acrylate (A) can be obtained, for example, by reacting a hydroxy(meth)acrylate with a diisocyanate and, if necessary, with a compound such as a polyol or a carboxylic acid.

[0040] Examples of the hydroxy(meth)acrylate include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate.

[0041] Examples of the diisocyanate include tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 2,2-dimethylpentane diisocyanate, 3-methoxyhexane diisocyanate, octamethylene diisocyanate, 2,2,4-trimethylpentane diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate, 3-butoxyhexane diisocyanate, dodecamethylene diisocyanate, and 4,4-biscyclohexylmethane diisocyanate. aliphatic diisocyanates such as isocyanate; and aromatic diisocyanates such as metaphenylene diisocyanate, paraphenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, dimethylbenzene diisocyanate, ethylbenzene diisocyanate, isopropylbenzene diisocyanate, 1,4-naphthalene diisocyanate, 1,5-naphthalene diisocyanate, 2,6-naphthalene diisocyanate, and 2,7-naphthalene diisocyanate.

[0042] Examples of the polyol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, dipropylene glycol, 3-methyl-1,5-pentanediol, 2-ethyl-2-butyl-1,3-propanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, and hydrogenated bis(isopropyl alcohol). Examples include dihydric alcohols such as phenol A, 1,4-dihydroxy-2-butene, 2,6-dimethyl-1-octene-3,8-diol, and bisphenol A; trihydric alcohols such as glycerin and trimethylolpropane; tetrahydric alcohols such as tetramethylolmethane (pentaerythritol) and diglycerin; pentahydric alcohols such as xylitol; hexahydric alcohols such as sorbitol, mannitol, allitol, iditol, dulcitol, altritol, inositol, and dipentaerythritol; heptahydric alcohols such as perseitol; and octahydric alcohols such as sucrose.

[0043] Examples of the carboxylic acid include dicarboxylic acids and trivalent or higher polycarboxylic acids. Examples of the dicarboxylic acid include aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, hexadecanedicarboxylic acid, and dimer acid; alicyclic dicarboxylic acids such as hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, and himic acid; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, methylisophthalic acid, and methylterephthalic acid; and derivatives thereof. Examples of polycarboxylic acids include propane-1,2,3-tricarboxylic acid, 2-methylpropane-1,2,3-triscarboxylic acid, butane-1,2,4-tricarboxylic acid, butane-1,2,3,4-tetracarboxylic acid, trimellitic acid, trimesic acid, hemimellitic acid, pyromellitic acid, benzenepentacarboxylic acid, cyclohexane-1,2,4-tricarboxylic acid, cyclohexane-1,3,5-tricarboxylic acid, cyclohexane-1,2,4,5-tetracarboxylic acid, naphthalene-1,2,4-tricarboxylic acid, naphthalene-2,5,7-tricarboxylic acid, pyridine-2,4,6-tricarboxylic acid, naphthalene-1,2,7,8-tetracarboxylic acid, and naphthalene-1,4,5,8-tetracarboxylic acid; or derivatives thereof.

[0044] The urethane di(meth)acrylate (A) may be used alone or in combination of two or more.

[0045] The content of the urethane di(meth)acrylate (A) in the polymerizable component is preferably 40 to 95% by mass.

[0046] The non-urethane polymerizable monomer (B) is at least one compound selected from the group consisting of non-urethane monofunctional polymerizable monomers (B1) and non-urethane bifunctional polymerizable monomers (B2).

[0047] The non-urethane polymerizable monomer (B) has neither a urethane bond nor an amide group in its molecule. This makes it easy to control the tensile elongation of the cured product to 10 to 60%. While the reasons for this are unclear, the following are thought to be the reasons. For example, the copolymerizability of a resin composition containing a monofunctional polymerizable monomer having a (meth)acrylamide group is thought to be lower than the copolymerizability of a resin composition consisting solely of a polymerizable monomer having a (meth)acrylic group. Therefore, the formation of a homopolymer of the monofunctional polymerizable monomer having a (meth)acrylamide group is rapid, resulting in a larger crosslinked product in the entire system, which is thought to increase the tensile elongation of the cured product.

[0048] The non-urethane monofunctional polymerizable monomer (B1) is a mono(meth)acrylate having a weight average molecular weight of 80 to 1000 and having neither a urethane bond nor an amide group in the molecule. The structure of the non-urethane monofunctional polymerizable monomer (B1) is not particularly limited, but may be, for example, represented by the following formula (2) or (2-1):

[0049]

[0050]

[0051] In the above formulas (2) and (2-1), R ９ is a hydrogen atom or a methyl group.

[0052] In the above formulas (2) and (2-1), R １０represents a substituted or unsubstituted hydrocarbon group, alkylcarbonyl group, or hydroxyalkyl group. Examples of hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, hexyl, 2-ethylhexyl, nonyl, and cyclohexyl; aryl groups such as phenyl; and aralkyl groups such as xylyl. Examples of substituents that substitute for the hydrocarbon group include halogen, alkoxy, aryloxyaryl, aryl ether, and phenoxyphenyl. Examples of alkylcarbonyl groups include acetyl, ethylcarbonyl, and propylcarbonyl groups. Examples of hydroxyalkyl groups include hydroxymethyl, hydroxyethyl, hydroxypropyl, hydroxyisopropyl, and hydroxybutyl groups.

[0053] In the above formula (2-1), R １１ represents an alkylene group such as a methylene group, an ethylene group, a propylene group, or an isopropylene group. d represents an integer of 1 or more. １１ When there are a plurality of, they may be the same or different.

[0054] The non-urethane monofunctional polymerizable monomer (B1) may be used alone or in combination of two or more. The photocurable composition preferably contains 5 to 40% by mass of the non-urethane monofunctional polymerizable monomer (B1).

[0055] The non-urethane bifunctional polymerizable monomer (B2) is a di(meth)acrylate having a weight average molecular weight of 500 to 2000 and having neither a urethane bond nor an amide group in the molecule. The structure of the non-urethane bifunctional polymerizable monomer (B2) is not particularly limited, but may be, for example, represented by the following formula (3) or (3-1):

[0056]

[0057]

[0058] In the above formulas (3) and (3-1), R １２ and R １３ are each independently a hydrogen atom or a methyl group.

[0059] In the above formula (3), R １４ is the above R ５ represents a hydrocarbon group having the same meaning as the above.

[0060] In the above formula (3-1), R １５ is the above R １１ represents an alkylene group having the same meaning as the above, and e represents an integer of 1 or more. １５ When there are a plurality of, they may be the same or different.

[0061] The non-urethane bifunctional polymerizable monomer (B2) may be used alone or in combination of two or more. The photocurable composition preferably contains 5 to 40% by mass of the non-urethane bifunctional polymerizable monomer (B2).

[0062] The photocurable composition of the present disclosure may contain, as a polymerizable component, other polymerizable components in addition to the urethane di(meth)acrylate (A) and the non-urethane polymerizable monomer (B). The other polymerizable components may include a monofunctional polymerizable monomer, a bifunctional polymerizable monomer, or a trifunctional or higher functional polymerizable monomer. In the photocurable composition, when the total mass of the polymerizable components is W (g) and the total amount of polymerizable groups of the bifunctional or higher functional polymerizable monomers contained in the polymerizable components is n (mmol), the ratio of the total amount of polymerizable groups (n (mmol)) to the total mass of the polymerizable components (W (g)): n / W (mmol / g) is preferably 0.3 to 3.0 (mmol / g), more preferably 1.0 to 2.5 (mmol / g). This makes it easier to control the physical properties of the cured product within a preferred range. The photocurable composition of the present disclosure preferably does not contain a trifunctional or higher functional polymerizable monomer as a polymerizable component.

[0063] <Photopolymerization Initiator> The photopolymerization initiator generates radicals in response to specific activation light, including light of a specific wavelength λ (nm) in the ultraviolet or visible light region. Dental treatment auxiliary devices can be manufactured using the liquid vat photopolymerization method described below. The liquid vat photopolymerization method can be performed using a commercially available stereolithography device. The specific wavelength λ (nm) can be determined appropriately depending on the wavelength of the activation light used in the stereolithography device. Examples of general-purpose stereolithography devices include SLA-type stereolithography devices that irradiate semiconductor laser light as activation light, DLP-type stereolithography devices that irradiate projector light, and LCD-type stereolithography devices that irradiate liquid crystal panel light. Light sources with activation light wavelengths of approximately 405 nm or approximately 385 nm are often used. In the present disclosure, the specific wavelength λ is preferably 405 nm or 385 nm, and the stereolithography device is preferably an SLA-type, DLP-type, or LCD-type.

[0064] The photopolymerization initiator may be appropriately selected from known photopolymerization initiators that satisfy the above conditions. The photopolymerization initiator to be selected is not particularly limited, and examples thereof include self-cleavage type photopolymerization initiators, bimolecular hydrogen abstraction type photopolymerization initiators, photoacid generators, and combinations thereof. These photopolymerization initiators may be used in combination with a photosensitizing dye, an electron-donating compound, or the like.

[0065] Suitable self-cleavage photopolymerization initiators include acylphosphine oxide compounds such as diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and 2,4,6-trimethylbenzoylethoxylphenylphosphine oxide; benzoketal compounds, benzyne compounds, α-aminoacetophenone compounds, α-hydroxyacetophenone compounds, titanocene compounds, and acyloxime compounds. Examples of photoacid generators include iodonium salt compounds such as p-isopropylphenyl-p-methylphenyliodonium tetrakispentafluorophenylborate salt; sulfonium salt compounds such as dimethylphenacylsulfonium hexafluoroantimonate salt; and halomethyl-substituted triazine compounds such as 2,4,6-tris(trichloromethyl)-s-triazine. Examples of photosensitizing dyes include ketone compounds, coumarin dyes, cyanine dyes, merocyanine dyes, thiazine dyes, azine dyes, acridine dyes, xanthene dyes, squarium dyes, pyrylium salt dyes, condensed polycyclic aromatic compounds (anthracene, perylene, etc.), thioxanthone compounds, etc. Examples of electron donors include 4-dimethylaminobenzoic acid esters, 4-dimethylaminotoluene, p-dimethoxybenzene, 1,2,4-trimethoxybenzene, thiophene compounds, etc.

[0066] The content of the photopolymerization initiator may be 0.01 to 10 parts by mass per 100 parts by mass of the polymerizable component. If the content of the photopolymerization initiator is too high, burrs and the like will appear in the obtained cured body, resulting in poor precision. On the other hand, if the content of the photopolymerization initiator is too low, it will be impossible to form a shape in the molding process.

[0067] <Other Components> The photocurable composition of the present disclosure may contain other components in addition to those described above. Known components used in photocurable compositions may be used as the other components. For example, the photocurable composition may contain an activating light absorber, a polymerization inhibitor, a thermal polymerization initiator, a coloring substance, etc.

[0068] 3. Manufacturing Method of Dental Treatment Auxiliary Instrument The dental treatment auxiliary instrument of the present disclosure can be manufactured using a liquid vat photopolymerization method. Here, the liquid vat photopolymerization method includes a process (hereinafter also referred to as a "molding process") in which, based on three-dimensional shape data representing the shape of a three-dimensional object (the main body of the dental treatment auxiliary instrument), the height direction of the three-dimensional object is digitized and ranked, and two-dimensional shape data representing the cross-sectional shape of the three-dimensional object at each ranked height is generated. Activating light is applied to a liquid photocurable composition held in a vat at predetermined positions determined based on the two-dimensional shape data to selectively (primarily) cure the liquid photocurable composition present at the predetermined positions to form modeling layers having the cross-sectional shape. Furthermore, modeling layers having the cross-sectional shapes at each height are sequentially formed and stacked in the ranked order to obtain a laminate having a shape corresponding to the shape of the three-dimensional object. The method for manufacturing a dental treatment auxiliary instrument may include a step of performing a cleaning treatment with an organic solvent (hereinafter, the step of performing such a treatment is also referred to as a "cleaning step") or a step of performing a secondary hardening treatment (hereinafter, the step of performing such a treatment is also referred to as a "secondary hardening step") as necessary.

[0069] The method for producing a dental treatment auxiliary instrument of the present disclosure is characterized by using the photocurable composition of the present disclosure as a liquid photocurable composition supplied into the tank of a liquid tank photopolymerization device. Because the photocurable composition of the present disclosure is used in the method for producing a dental treatment auxiliary instrument of the present disclosure, it is possible to produce a dental treatment auxiliary instrument that is easy to remove from a tooth to be restored and that causes little pain to the patient when the dental treatment auxiliary instrument is removed.

[0070] In the method for manufacturing a dental treatment auxiliary device of the present disclosure, the molding process includes: a first step of irradiating a predetermined position of a liquid photocurable composition held in a tank with activating light based on two-dimensional shape data at a height of an initial ranking order, thereby curing the composition, and forming a modeling layer having a shape corresponding to the two-dimensional shape data, and using the "modeling layer" as a bonded layer; a second step of moving the bonded layer up or down and supplying a liquid photocurable composition immediately above or below the bonded layer in the tank; a third step of irradiating a predetermined position of the liquid photocurable composition supplied immediately above or below the bonded layer, based on two-dimensional shape data at a height next in the ranking order in the previous step, with activating light to harden the composition, thereby forming a new modeling layer having a shape corresponding to the two-dimensional shape data, and bonding the new modeling layer to the bonded layer, thereby obtaining a laminate having the new modeling layer as a new bonded layer; and a fourth step of moving the laminate up or down and supplying a liquid photocurable composition immediately above or below the new bonded layer in the tank; and preferably, the cycle consisting of the third and fourth steps is repeated using the new bonded layer as the bonded layer in the third step, and in the final third step, a new modeling layer is formed based on the two-dimensional shape data at the height of the final ranking order to obtain a laminate.

[0071] Such a liquid vat photopolymerization method including a molding step can be suitably carried out using a commercially available liquid vat photopolymerization device known as a 3D printer. The three-dimensional shape data representing the shape of the dental treatment auxiliary instrument (three-dimensional object) used in the molding step can be CAD data designed based on digital data obtained by scanning the intraoral shape of an individual patient or an intraoral model created for each individual patient.

[0072] In the manufacturing method of the dental treatment auxiliary instrument of the present disclosure, after the molding step, it is preferable to wash the obtained laminate with an organic solvent (perform the washing step), and then perform secondary curing by additional irradiation with activating light, heat treatment, or both (perform the secondary curing step).

[0073] Examples of organic solvents used in the washing step include alcohol-based solvents such as ethanol, methanol, and isopropyl alcohol; ketone-based solvents such as acetone and methyl ethyl ketone; ether-based solvents such as diethyl ether, diisopropyl ether, tripropylene glycol monomethyl ether, and tetrahydrofuran; amide-based solvents such as N-methylpyrrolidone and dimethylacetamide; and halogen-based solvents such as methylene chloride and chloroform. Among these, alcohol-based solvents and ether-based solvents are preferred because of their high washing effect, and alcohol-based solvents are more preferred because of their low environmental impact.

[0074] To enhance the cleaning effect, an ultrasonic cleaner can be used. The laminate or a container containing the laminate immersed in an organic solvent or water is placed in water immersed in the ultrasonic cleaner, and ultrasonic waves are applied to clean the laminate. Ultrasonic cleaning can be performed while heating as needed.

[0075] The wavelength of the additional activating light irradiation in the secondary curing step is not particularly limited as long as it is a wavelength that can be absorbed by the photopolymerization initiator remaining in the laminate to generate radicals. Furthermore, when the photocurable composition of the present disclosure contains a thermal polymerization initiator, this can be used to perform secondary curing by heating. Furthermore, the above treatment can be performed while the laminate is immersed in water.

[0076] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0077] (Preparation of Photocurable Compositions) The photocurable compositions according to the examples and comparative examples were mixed in the formulations shown in Tables 1 and 2 below, and 1 part by mass of a polymerization initiator (BTPO: phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide) was further added to prepare the compositions. The numerical values ​​indicating the blending amount of each compound in Tables 1 and 2 refer to parts by mass. The compounds and their abbreviations in Tables 1 and 2 are shown below.

[0078] (Urethane di(meth)acrylate) UMA-200: urethane dimethacrylate (Mw: approx. 3000, manufactured by Shin-Nakamura Chemical Co., Ltd.) UN-333: urethane diacrylate (Mw: approx. 3000, manufactured by Negami Chemical Industries, Ltd.) EBECRYL9270: urethane diacrylate (Mw: approx. 1000, manufactured by Daicel Allnex) UN-6306: urethane diacrylate (Mw: approx. 6600, manufactured by Negami Chemical Industries, Ltd.)

[0079] (Non-urethane monofunctional polymerizable monomer (B1)) H-PR: 2-(methacryloyloxy)ethyl propionate (Mw: about 186, manufactured by Tateyama Chemical Co., Ltd.) POB-A: 3-phenoxybenzyl acrylate (Mw: about 254, manufactured by Kyoeisha Chemical Co., Ltd.)

[0080] (Non-urethane bifunctional polymerizable monomer (B2)) 14G: polyethylene glycol dimethacrylate (Mw: about 770, manufactured by Shin-Nakamura Chemical Co., Ltd.) 9G: polyethylene glycol dimethacrylate (Mw: about 550, manufactured by Shin-Nakamura Chemical Co., Ltd.)

[0081] (Other non-urethane monofunctional polymerizable monomers) DMAA: N,N-dimethylacrylamide (Mw: approximately 99, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0082] (Other non-urethane bifunctional polymerizable monomers) 3G: triethylene glycol dimethacrylate (Mw: approximately 286, manufactured by Shin-Nakamura Chemical Co., Ltd.)

[0083]

[0084]

[0085] (Evaluation) The photocurable compositions prepared in each of the Examples and Comparative Examples were cured by irradiating them with light for 5 minutes using an α Light V (a dental laboratory polymerization device manufactured by Morita Corporation) to obtain a cured product. The cured products were used as samples to measure tensile elongation, hardness, and elastic deformation power. The measurement and evaluation methods are described below.

[0086] (Measurement of Tensile Elongation) Each sample was punched into a No. 3 dumbbell shape in accordance with JIS K 6251, and the tensile elongation (elongation at break) was measured using a tensile tester with a chuck distance of 20 mm and a pulling speed of 500 mm / min. The results are shown in Tables 1 and 2.

[0087] (Hardness (Durometer Hardness) Measurement) The durometer hardness of each sample was measured in accordance with JIS K 6253. The measurement was performed using a type A indenter (cylindrical, φ1.25±0.15 mm, cone part: cone angle 35 degrees, φ0.79 mm). The results are shown in Tables 1 and 2.

[0088] (Elastic Deformation Power Measurement) According to the C method specified in JIS K 6254, each sample was cut into a cylindrical test piece with a diameter of 9.0 mm and a height of 13.0 mm, and a compression test was performed to measure the elastic deformation power (We) and the plastic deformation power (Wp). The elastic deformation power was calculated using the formula: 100 × {We / (Wp + We)}. The results are shown in Tables 1 and 2.

[0089] (Overall Evaluation for Use as a Clear Index) A dental treatment auxiliary device (Clear Index) was produced using the photocurable compositions according to each Example and Comparative Example. Specifically, a jaw model with an abutment tooth formed on the second left maxillary tooth was modeled using Model resin V3 (a resin for 3D printers manufactured by Formlabs) with a Form3B (3D printer manufactured by Formlabs). CAD data corresponding to the jaw model and having a cavity intended for filling the abutment tooth portion with composite resin was created, and each photocurable composition was used to model the cavity with Form2 (3D printer manufactured by Formlabs) and Mars4 (3D printer manufactured by Elegoo), resulting in a model (Clear Index) of the CAD data. This Clear Index was set in the jaw model, and the cavity in the abutment tooth portion was filled with Omnichromaflow (a composite resin manufactured by Tokuyama Dental Co., Ltd.). After light curing using ELIPAR (registered trademark, a light curing device manufactured by 3M Co.), the Clear Index was torn and removed. The performance of the Clear Index during the above process was evaluated according to the following evaluation criteria. The results are shown in Tables 1 and 2.

[0090] Evaluation Criteria 1: The ease of setting the Clear Index on the jaw model, the durability of the Clear Index itself, and the ease of removing the Clear Index were evaluated according to the following evaluation criteria. A: When setting the Clear Index on the jaw model, it can be set easily and without breaking. When removing it from the jaw model, it can be easily torn. B1: When setting the Clear Index on the jaw model, if too much force is applied, it may break, but this is within an acceptable range. When removing it from the jaw model, it can be easily torn. B2: When setting the Clear Index on the jaw model, it can be set easily and without breaking. When removing it from the jaw model, some force is required, but it can be torn and removed by deforming it significantly, which is within an acceptable range. C: When setting the Clear Index on the jaw model, it can be set without breaking. When removing it from the jaw model, the Clear Index stretches too much, requiring considerable force to tear and remove it. D: When setting the Clear Index on the jaw model, it breaks and cannot be used.

[0091] Evaluation Criteria 2: The ease of deformation when a load is applied to the Clear Index and the time required for it to return to its original shape after deformation were evaluated according to the following evaluation criteria. A: It can be deformed by applying a moderate load, and it immediately returns to its original shape after deformation. B1: It can be deformed by applying a moderate load, but it takes more than one second to return to its original shape after deformation. B2: It deforms with just a small load, but it immediately returns to its original shape after deformation. B3: It requires a large load to deform, but it immediately returns to its original shape after deformation. C1: It deforms with just a small load, and it takes more than one second to return to its original shape after deformation. C2: It requires a large load to deform, and it takes more than one second to return to its original shape after deformation.

[0092] Overall evaluation for clear index use: The evaluation results for evaluation criterion 1 and evaluation criterion 2 were combined and evaluated as shown below, with 4 and 3 being considered pass. 4: The evaluation result for evaluation criterion 1 was A, and the evaluation result for evaluation criterion 2 was A. 3: The evaluation result for evaluation criterion 1 was B1 or B2, and the evaluation result for evaluation criterion 2 was A. 2: The evaluation result for evaluation criterion 1 was C or D, and the evaluation result for evaluation criterion 2 was A. 1: The evaluation result for evaluation criterion 1 was C or D, and the evaluation result for evaluation criterion 2 was any of B1, B2, B3, C1, and C2.

[0093] 1, 1a Dental treatment auxiliary tool 2, 2a Picking piece

Claims

1. A dental treatment auxiliary instrument that is a molded body made of an elastically deformable and translucent resin material, the dental treatment auxiliary instrument having a cap-shaped main body with an open recess capable of accommodating at least the portion of a patient's tooth to be restored, the portion accommodating at least the portion to be restored having an inner surface shape that corresponds to the pre-designed outer surface shape of the tooth after the portion to be restored has been restored, when the main body is elastically deformed and attached to the tooth to be restored, a cavity is formed by the outer surface of the portion to be restored and the inner surface shape, when the dental treatment auxiliary instrument is attached to the tooth to be restored, a dental photocurable composition introduced into the cavity is irradiated with light to harden the dental photocurable composition, thereby restoring the tooth to be restored, the resin material having a tensile elongation of 10-60% in accordance with JIS K 6251.

2. A dental treatment auxiliary instrument as set forth in claim 1, wherein the resin material has a durometer hardness of 60 to 89 in accordance with JIS K 6253, and the resin material has an elastic deformation power of 70 to 100% when the elastic deformation power (%) is calculated using the formula 100 x {We / (Wp+We)} based on the elastic deformation power We (unit: kgf m / s) and the plastic deformation power Wp (unit: kgf m / s) determined in a compression test conducted in accordance with Method C of JIS K 6254 using a cylindrical test piece with a diameter of 9.0 mm and a height of 13.0 mm.

3. The dental treatment auxiliary instrument according to claim 1, wherein the opening recess in the main body has a gripping piece and / or a tearing notch on the periphery of the opening.

4. A polymerizable component comprising at least one non-urethane polymerizable monomer (B) selected from the group consisting of a urethane diacrylate or urethane dimethacrylate (A) having a weight average molecular weight of 1,000 to 20,000, a non-urethane monofunctional polymerizable monomer (B1) consisting of a monoacrylate or monomethacrylate having a weight average molecular weight of 80 to 1,000 and having neither a urethane bond nor an amide group in the molecule, and a non-urethane bifunctional polymerizable monomer (B2) consisting of a diacrylate or dimethacrylate having a weight average molecular weight of 500 to 2,000 and having neither a urethane bond nor an amide group in the molecule, and a photopolymerization initiator, wherein the content of (A) in the polymerizable component is 40 to 95% by mass, a photocurable composition in which, when the total mass of the polymerizable components is W (g) and the total amount of polymerizable groups of bifunctional or higher functional polymerizable monomers contained in the polymerizable components is n (mmol), the ratio of the total amount of the polymerizable groups: n (mmol) to the total mass of the polymerizable components: W (g), n / W (mmol / g) is 0.3 to 3.0 (mmol / g).

5. The photocurable composition according to claim 4, which contains the non-urethane bifunctional polymerizable monomer (B2).

6. The photocurable composition according to claim 4, which is used to produce the resin material in the dental treatment auxiliary instrument according to claim 1.

7. A method for manufacturing an auxiliary instrument for dental treatment as defined in claim 1, comprising the steps of: digitizing and ranking the height direction of the main body from three-dimensional shape data representing the shape of the main body portion, and generating two-dimensional shape data representing the cross-sectional shape of the main body portion at each ranked height; irradiating a liquid photocurable composition held in a tank with activating light at a predetermined position determined in advance based on the two-dimensional shape data, thereby selectively curing the liquid photocurable composition present at that position to form a modeling layer having the cross-sectional shape; and sequentially forming and stacking modeling layers having the cross-sectional shape at each height in the order of the ranking, thereby obtaining a laminate having a shape corresponding to the shape of the main body portion; and a manufacturing method for an auxiliary instrument for dental treatment, using the photocurable composition defined in claim 4 as the liquid photocurable composition.

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