WO2016080281A1 - Model tooth for dental practice and method for manufacturing same - Google Patents

Model tooth for dental practice and method for manufacturing same Download PDF

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Publication number
WO2016080281A1
WO2016080281A1 PCT/JP2015/081884 JP2015081884W WO2016080281A1 WO 2016080281 A1 WO2016080281 A1 WO 2016080281A1 JP 2015081884 W JP2015081884 W JP 2015081884W WO 2016080281 A1 WO2016080281 A1 WO 2016080281A1
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Prior art keywords
enamel
dentin
urea resin
model tooth
resin
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PCT/JP2015/081884
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French (fr)
Japanese (ja)
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暁春 賈
尾瀬　和久
明宏 東村
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株式会社ニッシン
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Publication of WO2016080281A1 publication Critical patent/WO2016080281A1/en

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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09B—EDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS
    • G09B23/00—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes
    • G09B23/28—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes for medicine

Definitions

  • the present invention relates to a dental training model tooth and a manufacturing method thereof.
  • Natural extracted teeth may be used as practice material for dentists or dental students to experience intraoral work for dental treatment.
  • Naturally extracted teeth are a preferred material for practitioners of dental treatment to memorize tooth cutting feeling, tooth structure, and root canal shape during actual treatment.
  • natural extracted teeth have a problem in that they need to be preserved due to corruption and hygiene problems.
  • model tooth made of a synthetic material has been proposed as a practice material for intraoral work that replaces natural extracted teeth (see, for example, Patent Document 1).
  • model teeth for example, those manufactured using an epoxy resin are distributed.
  • the present invention relates to a dental training model tooth that has a good cutting feeling close to that of natural teeth and can be produced by a highly efficient method, and a dental training model that can manufacture the dental training model tooth with high efficiency. It is an object of the present invention to provide a method for manufacturing a tooth.
  • the inventors of the present invention have a dental training model tooth including a dentin part and an enamel part joined to the dentin part, and the dentin part and the enamel part contain a urea resin, whereby The present inventors have found that the above problems can be solved and have completed the present invention. Specifically, the present invention provides the following.
  • a dental practice model tooth comprising a dentin part and an enamel part, wherein at least one of the dentin part and the enamel part contains a urea resin.
  • the dentin part and the enamel part are separately formed in the same mold in a state where both are joined by multilayer injection molding using a urea resin or a composition containing a urea resin.
  • the dental training model tooth which has a favorable cutting feeling close
  • a model tooth 10 according to the present invention includes an enamel portion 11 and a dentin portion 12. At least one of the enamel part 11 and the dentin part 12 contains a urea resin.
  • the model tooth 10 may be formed as a single part by seamlessly integrating the enamel portion 11 and the dentin portion 12. Also, the model tooth 10 may be configured by joining the enamel part 11 and the dentin part 12, which are separate parts, so that the enamel part 11 is in close contact with the surface of the dentin part 12.
  • the shapes of the enamel portion 11 and the dentin portion 12 are not particularly limited as long as the shape of the desired intraoral work can be practiced.
  • the shape of the enamel portion 11 and the dentin portion 12 is preferably a shape imitating the shapes of the enamel and the dentin constituting the natural tooth.
  • the shape of the enamel portion 11 is natural. It is preferably a shape simulating the shape of enamel in the tooth.
  • the thickness of the thickest portion of the enamel portion 11 is preferably 1 to 3 mm, and more preferably 2 to 2.5 mm.
  • the enamel portion 11 and the dentin portion 12 contains a urea resin.
  • the enamel part 11 and the dentin part 12 may be comprised only with urea resin, and may be comprised with the urea resin composition containing components other than urea resin and urea resin.
  • the material that does not contain the urea resin is selected from various materials that have been conventionally used as model tooth materials. be able to.
  • the urea resin composition may contain various additives such as a filler, a colorant, a resin component other than the urea resin, and an ultraviolet absorber. . These components contained in the urea resin composition will be described later.
  • the material of the enamel part 11 and the material of the dentin part 12 may be the same or different. From the viewpoint that the model tooth 10 can be easily manufactured and the model tooth 10 can be manufactured at low cost, the material of the enamel portion 11 and the material of the dentin portion 12 are the same urea resin or urea resin composition. Is preferred.
  • the structure of the model tooth 10 is preferably a structure composed of a single part in which the enamel portion 11 and the dentin portion 12 are seamlessly integrated.
  • the urea resin or the urea resin composition is excellent in adhesiveness with a filling resin material (composite resin) used for filling a cut portion of a tooth to be treated in dental treatment.
  • model teeth 10 when the material of the enamel portion 11 and the material of the dentin portion 12 are the same material, the difference in texture between the enamel and the dentin in the natural tooth cannot be expressed.
  • the material of the enamel part 11 and the material of the dentin part 12 are used from the viewpoint of manufacturing the model tooth 10 closer to the natural tooth. Are preferably different from each other.
  • one of the material of the enamel part 11 and the material of the dentin part 12 may be a material other than the urea resin or the urea resin composition.
  • the dentin portion 12 is made of a urea resin or a urea resin composition.
  • Enamel is a harder tissue than dentin. For this reason, it is preferable that the enamel part 11 is designed to be harder than the dentin part 12.
  • the material of the enamel part 11 is not limited to a urea resin or a urea resin composition, For example, even if it is a hard inorganic material like a ceramic. Good.
  • the material of the enamel part 11 and the dentin part 12 is a urea resin composition or a composition containing a resin other than the urea resin, the hardness of the enamel part 11 and the dentin part 12 is as described later. It adjusts by mix
  • a dental pulp portion 13 may be formed on the dentin portion 12 as necessary.
  • the dentin and the pulp are recognized as different tissues, but in the present specification, the pulp portion 13 is described as a part of the dentin portion 12.
  • the dentin part 12 preferably includes a pulp part 13.
  • it is easy to practice treatment such as medullary spread, root canal enlargement, root canal filling using the model tooth 10.
  • Examples of the method of providing the pulp portion 13 in the dentin portion 12 include a method of coloring a portion corresponding to the pulp portion 13 in the dentin portion 12 according to a known method.
  • a plurality of parts of the dentin part 12 divided into two or more by a cross section substantially parallel to the length direction of the pulp part 13 is manufactured, and corresponds to the pulp part 13 on the divided surface in the plurality of parts.
  • the portion to be processed may be colored with a hue different from the hue of the dentin portion 12, and then a plurality of parts may be joined using an adhesive or the like to form the dentin portion 12.
  • a material that forms the pulp portion 13 in the hole after the dentin portion 12 having a hole having a shape corresponding to the pulp portion 13 is formed in advance.
  • the method of filling is included.
  • the material which comprises the dental pulp part 13 will not be restrict
  • Examples of the material constituting the dental pulp portion 13 include a curable resin that has fluidity when filled and can be cured after filling.
  • the curable resin may be a thermosetting resin or a photocurable resin, and examples thereof include an epoxy resin, a melamine resin, a urea resin, an acrylic resin, and a silicone resin.
  • the method for joining the enamel part 11 and the dentin part 12 is not particularly limited.
  • the enamel part 11 and the dentin part 12 may be physically fitted and joined together.
  • the enamel portion 11 and the dentin portion 12 may be directly joined in a mold by using a multicolor injection molding method.
  • the urea resin, the filler, the inorganic material, the resin component other than the urea resin, the colorant, other additives, and the adhesive will be described in order with respect to the material of the model tooth 10 or the model tooth 10 part.
  • the urea resin is prepared by thermosetting a urea resin precursor.
  • the urea resin precursor include a mixture containing urea and formaldehyde, and a urea formaldehyde resin obtained by polymerizing urea and formaldehyde to some extent.
  • Urea resin precursors formaldehyde, hexamethylenetetramine, oxalic acid dimethyl ester, phthalic anhydride, organic halides, amine hydrochlorides, and salicylic acid urea adducts for the purpose of accelerating thermosetting and reducing loss of formaldehyde.
  • a curing catalyst such as
  • urea resin precursor urea resin precursors used in the production of various molded products can be used without particular limitation. Further, the urea resin may be modified by various known methods within a range not impairing the object of the present invention.
  • the model tooth By using urea resin or urea resin composition containing urea resin as the material of the model tooth, the model tooth in which the problems related to cutting feeling and discoloration during long-term storage related to the model tooth formed using epoxy resin are solved. Can be manufactured.
  • urea resin precursor one having fluidity and applicable to injection molding is preferable. After the urea resin precursor is injected into the heated mold, the urea resin precursor is cured in the mold to form an enamel portion and a dentin portion containing the urea resin.
  • urea resin precursors applicable to injection molding include, for example, Readwrite (registered trademark) WT-2086, Readwrite (registered trademark) Toughamine INT2064W, Readwrite (registered trademark) W420, manufactured by Taiwa Co., Ltd. And Readwrite (registered trademark) Y2127, and CU-Y, CU-E, CZ-T, and CZ-F manufactured by Panasonic Corporation.
  • Commercially available urea resin precursors can also be used by blending components such as fillers described later.
  • urea resin precursor applicable to injection molding, it is possible to produce model teeth or parts constituting the model teeth with significantly higher efficiency than the casting method.
  • dimensional accuracy, mold shape reproducibility, and burr Problems such as occurrence are resolved.
  • the material constituting the enamel part and the dentin part is preferably a urea resin composition containing a filler from the viewpoint of model tooth productivity.
  • the urea resin composition containing a filler the cutting feeling of an enamel part and a dentin part can be adjusted by selecting the kind of filler, content, the shape of a filler, etc. suitably.
  • the said resin composition may contain the filler demonstrated below similarly to a urea resin composition. .
  • the content of the filler is the same as that of the urea resin composition.
  • filler organic or inorganic fillers conventionally blended in various resin compositions can be used.
  • shape of the filler is not particularly limited, and for example, a fibrous filler or a powdery or plate-like filler can be used.
  • the urea resin composition may contain a combination of two or more fillers.
  • fibrous filler examples include glass fiber, milled glass fiber, carbon fiber, cellulose fiber, ceramic fiber, zirconia fiber, silica fiber, titanium oxide fiber, silicon carbide fiber, rock wool, potassium titanate whisker, and barium titanate whisker. , Aluminum borate whiskers, and metal fibers.
  • silica, mica, talc, kaolin, calcium carbonate, glass beads, glass flakes, barium glass, zirconium glass, zirconium oxide, zirconium silicate, barium sulfate, clay, wollastonite examples include alumina, zinc oxide, titanium oxide, magnesium oxide, and graphite.
  • titanium oxide, cellulose fiber, glass fiber, silica, and barium glass are preferred because it is easy to bring the cutting feeling of model teeth close to the cutting feeling of natural teeth, silica, and Barium glass is more preferred, and silica is particularly preferred.
  • the filler to be blended is subjected to a surface treatment in advance in order to improve the familiarity and wettability with the urea resin.
  • Preferred surface treatment materials include silane coupling agents, titanate coupling agents, aluminate coupling agents, zirconate coupling agents, and the like.
  • the usage-amount of a surface treating agent is suitably adjusted according to the specific surface area of a filler.
  • a composite resin comprising a urea resin and a surface-treated filler is molded into an enamel part and a dentin part. The enamel part and the dentin part thus produced have improved hardness, tensile strength, impact resistance and the like.
  • a filler having an X-ray contrast property is preferable because the X-ray contrast property can be imparted to the model tooth while adjusting the cutting feeling.
  • the filler having X-ray contrast properties include barium glass, zirconium glass, zirconium oxide, barium oxide, zirconium silicate, and barium sulfate. Among these, zirconium oxide is preferable from the viewpoint of X-ray contrast properties.
  • the amount of the filler having X-ray contrast properties is not particularly limited, and is typically preferably 1 to 80% by mass with respect to the mass of the urea resin composition. From the viewpoint of achieving both X-ray contrast properties and moldability of the model teeth, the amount of the filler having X-ray contrast properties is preferably 1 to 20% by mass with respect to the mass of the urea resin composition. 3 to 15% by mass is more preferable, and 3 to 10% by mass is particularly preferable.
  • the amount of filler having X-ray contrast is The amount of the urea resin composition is preferably 1 to 30% by mass, more preferably 3 to 20% by mass, and particularly preferably 5 to 15% by mass.
  • the filler having X latent contrast is a glass component such as barium glass or zirconia glass
  • the amount of filler having X contrast is 20 to 80% by mass with respect to the mass of the urea resin composition. 30 to 70% by mass is more preferable, and 40 to 60% by mass is particularly preferable.
  • filler having X-ray contrast properties for example, those sold by Daiichi Rare Element Chemical Co., Ltd., Kinsei Matec Co., Ltd., Nippon Frit Co., Ltd., NEC SCHOTT Components Co., Ltd., or the like can be used.
  • the enamel part and the dentin part can be formed using dental treatment tools such as bars, reamers, and files.
  • the feeling of cutting when cutting is adjusted.
  • the cutting feeling of the enamel part and the dentin part varies depending on the type of filler, but is generally prepared by adjusting the Vickers hardness of the material of the enamel part and the dentin part.
  • the greater the filler content in the urea resin composition the higher the Vickers hardness of the enamel part and dentin part formed using the urea resin composition.
  • the larger the filler size the higher the Vickers hardness of the enamel part and the dentin part.
  • the large size of the filler means that the average particle diameter of the filler is large for the powdery or plate-like filler, and the fiber length and the fiber diameter of the filler for the fibrous filler. It means that at least one is large.
  • the Vickers hardness of the enamel portion is about 200 to 400 like a natural tooth.
  • the Vickers hardness of the material of the enamel part is preferably 40 to 200, 40 to 150, or 40 to 100.
  • the Vickers hardness of the dentin portion material is adjusted to a value lower than the Vickers hardness of the enamel portion material.
  • the blending amount of the filler in the urea resin composition when adjusting the Vickers hardness of the enamel part and the dentin is not particularly limited as long as the Vickers hardness of the enamel part and the dentin is a desired value.
  • the blending amount of the filler is preferably 1 to 50% by mass, more preferably 5 to 40% by mass, and particularly preferably 10 to 40% by mass with respect to the mass of the urea resin composition.
  • the filler blended in the urea resin composition and the relationship between the filler and the cutting feeling of the model teeth have been described, but as a filler, it is possible to form a model tooth with a cutting feeling close to natural teeth.
  • Silica and barium glass are preferred, and silica is more preferred.
  • the filler is silica
  • natural teeth are provided by using a urea resin composition containing 5 to 50% by mass, preferably 20 to 40% by mass of silica, based on the mass of the urea resin composition.
  • An enamel portion having a cutting feeling very close to that of enamel can be formed.
  • a hard inorganic material may be used as a material for the enamel portion in order to create a model tooth having a cutting feeling close to that of a natural tooth.
  • a hard inorganic material include ceramic.
  • the type of ceramic is not particularly limited as long as it is conventionally used as a model tooth material.
  • the method for producing an enamel part made of an inorganic material is not particularly limited.
  • the enamel portion made of an inorganic material is manufactured using a known processing method according to the material.
  • the Vickers hardness of the material of the enamel part is preferably 200 to 420, in order to manufacture a model tooth having a cutting feeling close to that of a natural tooth.
  • the range is preferably 250 to 380, particularly preferably 270 to 370.
  • a resin component other than the urea resin may be included in addition to the urea resin as long as the object of the present invention is not impaired.
  • the resin component other than the urea resin may be a thermoplastic resin or a thermosetting resin.
  • the resin component other than the urea resin is preferably a thermosetting resin from the viewpoint of cutting feeling of the model teeth.
  • the urea resin composition includes a resin component other than the urea resin
  • the urea resin and the resin component other than the urea resin may be compatible with each other, and either the urea resin or the resin component other than the urea resin may be used.
  • a sea-island structure in which one is a sea component and the other is an island component may be formed.
  • the resin component other than the urea resin is a thermoplastic resin
  • the resin component other than the urea resin is a thermoplastic resin
  • the resin component other than the urea resin is a thermoplastic resin
  • the resin component other than the urea resin is a thermoplastic resin
  • polyacetal resin polyamide resin, polycarbonate resin, polyester resin (polybutylene terephthalate, polyethylene terephthalate, polyarylate, etc.), FR-AS resin, FR -ABS resin, AS resin, ABS resin, polyphenylene oxide resin, polyphenylene sulfide resin, polysulfone resin, polyethersulfone resin, polyetheretherketone resin, fluorine resin, polyimide resin, polyamideimide resin, polyamide bismaleimide resin, polyether Imide resin, polybenzoxazole resin, polybenzothiazole resin, polybenzimidazole resin, BT resin, polymethylpentene, ultrahigh molecular weight polyethylene, FR-poly Propy
  • the resin component other than the urea resin is a thermosetting resin
  • a thermosetting resin include a phenol resin, a melamine resin, an epoxy resin, and an alkyd resin.
  • the content of the urea resin in the resin component contained in the urea resin composition is 50% by mass.
  • 70% by mass or more is more preferable, 90% by mass or more is particularly preferable, and 95% by mass or more is most preferable.
  • the enamel part and the dentin part may be transparent or colored. Further, only one of the enamel part and the dentin part may be colored. It is preferable that both the enamel part and the dentin part are colored. In this case, the enamel part and the dentin part are preferably colored with a hue close to the hue of a natural tooth. Specific examples of hues close to natural teeth include white, ivory, milky white, A2 color, and A3 color. These hues may be translucent.
  • the dentin part When both the enamel part and the dentin part are colored with a hue close to the hue of natural teeth, it is possible to work with the same feeling as the work on natural teeth during training using model teeth There is.
  • the dentin part When the dentin part is transparent, the dentin part preferably comprises a colored pulp part. In this case, there is an advantage that the visibility of the dental pulp portion is good during the practice using the model teeth.
  • the colorant is not particularly limited as long as it can color the enamel part and the dentin part to a desired hue and does not cause discoloration or fading by heating during molding.
  • Various known colorants are used. be able to.
  • Preferred examples of the colorant include pigments such as yellow ocher, bengara, ultramarine blue, black iron oxide, and titanium white (titanium dioxide).
  • the amount of colorant used is not particularly limited.
  • the colorant is used in an amount such that the enamel part or dentin part has the desired hue and transparency.
  • the thickness of the coating film is preferably as thin as possible so as not to impair the cutting feeling of the model teeth.
  • the material constituting the enamel part and the dentin part may contain various additives in addition to the filler, the resin component other than the urea resin, and the colorant.
  • Suitable additives include, for example, antioxidants, ultraviolet absorbers, mold release agents, plasticizers and the like.
  • the kind of adhesive agent will not be specifically limited as long as an enamel part and a dentin part can be favorably joined.
  • various types of adhesives such as radical polymerization type adhesives, ion polymerization type adhesives such as cationic polymerization type and anion polymerization type, melamine / urea co-condensation resin adhesives, epoxy adhesives, etc. may be used. it can.
  • a photocurable anionic polymerization type adhesive is preferable.
  • the photocurable anionic polymerization type adhesive include a photocurable instantaneous adhesive containing 2-cyanoacrylate and a photoinitiator.
  • the melamine resin or melamine resin composition is inferior in adhesiveness to a photocurable anionic polymerization type adhesive.
  • the urea resin or urea resin composition has good adhesion to a photocurable anionic polymerization type adhesive. For this reason, when a photocurable anionic polymerization type adhesive is used, the enamel portion and the dentin portion each containing a urea resin are particularly well bonded.
  • the model tooth according to the present invention is obtained by joining the enamel portion and the dentin portion formed using the materials described above.
  • the joint surface of the parts joined using the adhesive may be roughened by a method such as sand blasting or chemical etching. By roughening the bonding surface before bonding, the model tooth parts can be bonded more firmly.
  • the method for producing the model tooth according to the present invention is not particularly limited, and various molding methods applied to the urea resin can be employed.
  • the injection molding method is preferable because the productivity of the model teeth is good.
  • a model tooth is obtained by joining the enamel part and the dentin part produced by injection molding.
  • the above-mentioned adhesive agent is used.
  • the enamel part and the dentin part may be manufactured as parts divided into two or more. In this case, the divided parts are joined to form an enamel part and a dentin part.
  • a specific example of the injection molding apparatus is EC-60 (manufactured by Toshiba Corporation, maximum injection pressure 2450 kg / cm 2 , mold clamping force 60 ton).
  • Preferred conditions for injection molding of the urea resin precursor using EC-60 are as follows. Mold temperature: 145 to 160 ° C on the fixed side, 145 to 160 ° C on the movable side Cylinder temperature: front 80-100 ° C, rear 40-70 ° C Injection pressure: 60-140 MPa Screw rotation speed: 30-60rpm Curing time: 20-40 seconds
  • a multilayer injection molding method can be applied to the manufacture of model teeth.
  • the enamel portion and the dentin portion are formed in a state where both are joined in the same mold. According to this method, since the work of joining the enamel part and the dentin part is unnecessary, the productivity of the model tooth is particularly good.
  • Example 1 Using the urea resin precursor I having the following composition and a mold having a hollow portion shaped like an enamel provided in natural teeth, injection molding was performed under the following conditions to obtain an enamel portion.
  • Urea formaldehyde resin (Readlight (registered trademark) WT-2086, manufactured by Taiwa Co., Ltd.): 70 parts by mass Cellulose: 22 parts by mass Zirconium oxide: 5 parts by mass Titanium white: 3 parts by mass Formaldehyde: 1 part by mass Hexamethylenetetramine: 1
  • Injection molding was performed under the above conditions using a urea resin precursor II having the following composition and a mold having a cavity shaped like a dentin included in a natural tooth to obtain a dentin part.
  • the dentin part was manufactured as a part divided into two parts. After coloring the part corresponding to the pulp part of the two divided parts, the two parts are bonded by using an adhesive (TB1773E, manufactured by ThreeBond Co., Ltd., an anionic polymerization photocuring instant adhesive) and dentin Part was formed.
  • Various adhesives such as radical polymerization type instantaneous adhesive (for example, V2 manufactured by Arteco Co., Ltd.) and melamine / urea co-condensation resin adhesive can be used as the adhesive.
  • the obtained enamel part and dentin part were joined using an adhesive (TB1773E, manufactured by ThreeBond Co., Ltd., photocuring imparted instantaneous adhesive by anionic polymerization) to obtain a model tooth.
  • the enamel part and the dentin part were not easily peeled off, and the adhesiveness between the enamel part and the dentin part was good.
  • a part of the model tooth obtained was cut to form a recess in the model tooth, and then the recess formed with an acrylic resin composite resin was filled and cured. After the composite resin was cured, the vicinity of the filled portion of the composite resin was cut with a high-speed rotating air turbine (300,000 rpm), but the composite resin was not peeled off due to the impact of the cutting. That is, the model tooth of Example 1 has good adhesiveness with the composite resin.
  • Example 2 an enamel part and a dentin part are formed using a urea resin precursor having the following composition, and a model tooth is produced by joining the enamel part and the dentin part in the same manner as in Example 1. did.
  • the content of the filler in the model tooth material is set to the amount (% by mass) described in Table 1, and is described in Table 1.
  • An enamel part and a dentin part are formed using a urea resin precursor obtained by blending various kinds of fillers, and the enamel part and the dentin part are joined in the same manner as in Example 1. Teeth were made.
  • ⁇ Formability evaluation> The moldability at the time of injection molding was evaluated according to the following criteria. In addition, about the model tooth of the comparative example 1, since it is not manufactured by injection molding, a moldability cannot be evaluated. As for moldability, resin flowability and releasability during molding and appearance of the product (existence of gloss; presence of burrs, sink marks, flow marks, warpage, jetting, weld lines, burns, and bubbles) Based on the above, it was rated in four levels, ⁇ , ⁇ , ⁇ , and ⁇ .
  • the model teeth of Examples 2 to 8 manufactured using urea resin have a cutting feeling equivalent to or close to natural teeth. Further, from Examples 3 to 8, when the material constituting the model tooth includes a filler, it is easy to obtain a model tooth having a cutting feeling closer to that of natural teeth, and when the filler is silica, the cutting feeling is obtained. It can be seen that it is easy to obtain model teeth that are particularly good. On the other hand, it can be seen that the model tooth of Comparative Example 1 made of an epoxy resin has a feeling of cutting far from natural teeth.
  • Example 2 shows that when a model tooth is manufactured by injection molding using a urea resin precursor containing no filler, the moldability is extremely good. From Examples 3 to 8, the urea resin precursor is obtained. It can be seen that the moldability by injection molding is not significantly impaired even when the body contains a filler.
  • Example 9 to 15 the content of the filler (filler having X-ray contrast properties) in the model tooth material is the amount (% by mass) shown in Table 2 with respect to the urea resin precursor having the following composition:
  • the enamel part and the dentin part are formed using the urea resin precursor obtained by blending the fillers of the type shown in Table 2, and the enamel part is formed in the same manner as in Example 1. And dentin part were joined to make a model tooth.
  • Urea formaldehyde resin (Readlight (registered trademark) WT-2086, manufactured by Taiwa Co., Ltd.): 70 parts by mass Titanium white: 3 parts by mass Formaldehyde: 1 part by mass Hexamethylenetetramine: 1 part by mass
  • the obtained model teeth of Examples 9 to 15 were evaluated for X-ray contrast, color tone, and moldability according to the following methods. These evaluation results are shown in Table 2.
  • ⁇ X-ray contrast> The model teeth were X-rayed according to the method described in “D3.2 When using digital X-ray equipment” in Annex D of JIS T6609-2. The obtained image was observed and X-ray contrast property was evaluated according to the following criteria. ⁇ : An image of a model tooth with a very clear shape is confirmed. ⁇ : An image of a model tooth with a clear shape is confirmed. ⁇ : An image of a model tooth with a slightly unclear shape is confirmed. The image was not confirmed
  • ⁇ Color tone> The color tone of the obtained model tooth was observed visually, and the color tone of the model tooth was evaluated according to the following criteria.

Abstract

The present invention provides: a model tooth for dental practice having an excellent feel of cutting similar to that of a natural tooth, it being possible to produce the model tooth for dental practice using even a highly efficient method; and a method for manufacturing the model tooth for dental practice with which it is possible to highly efficiently manufacture the model tooth for dental practice. A model tooth for dental practice provided with a dentine part and an enamel part that is joined to the dentine part, the model tooth for dental practice being configured such that the dentine part and the enamel part contain urea resin. The method for manufacturing the model tooth for dental practice preferably includes an injection molding step for forming the dentine part and the enamel part by injection molding using urea resin or a urea resin composition, and a joining step for joining the dentine part and the enamel part together.

Description

歯科実習用模型歯及びその製造方法Dental practice model teeth and method for manufacturing the same
　本発明は、歯科実習用模型歯及びその製造方法に関する。 The present invention relates to a dental training model tooth and a manufacturing method thereof.
　歯科医師又は歯科学生が、歯科治療のための口腔内作業を体験する目的で、練習材料として天然の抜去歯が使用されることがある。天然の抜去歯は、歯科治療の練習者が、実際の治療時の歯の切削感や、歯牙の構造、根管の形態を記憶するためには好ましい材料である。しかし、天然の抜去歯は、腐敗や衛生上の問題からその保存に注意を要する点で問題がある。 Natural extracted teeth may be used as practice material for dentists or dental students to experience intraoral work for dental treatment. Naturally extracted teeth are a preferred material for practitioners of dental treatment to memorize tooth cutting feeling, tooth structure, and root canal shape during actual treatment. However, natural extracted teeth have a problem in that they need to be preserved due to corruption and hygiene problems.
　そこで、天然の抜去歯に変わる口腔内作業の練習材料として、合成材料（樹脂）からなる模型歯が提案されている（例えば特許文献１を参照）。模型歯としては、例えば、エポキシ樹脂を用いて製造されたものが流通している。 Therefore, a model tooth made of a synthetic material (resin) has been proposed as a practice material for intraoral work that replaces natural extracted teeth (see, for example, Patent Document 1). As model teeth, for example, those manufactured using an epoxy resin are distributed.
特開２００２－０００６２８号公報JP 2002-000628 A
　しかし、エポキシ樹脂を用いて製造された模型歯について、天然の歯牙と比較して、切削感が大きく異なる問題がある。また、エポキシ樹脂を用いて模型歯を製造する場合、通常、硬化前のエポキシ樹脂をモールド内に注型した後、エポキシ樹脂を熱硬化させて模型歯が製造される。ところが、このような方法で模型歯を製造する場合、金型の形状再現性が悪く、形状のバラツキが生じやすい。また、注型法は、非常に生産性に劣る点でも問題である。 However, there is a problem that the cutting feeling of the model teeth manufactured using the epoxy resin is greatly different from that of natural teeth. Moreover, when manufacturing a model tooth using an epoxy resin, after casting the epoxy resin before hardening in a mold, a model tooth is manufactured by thermosetting an epoxy resin normally. However, when the model teeth are manufactured by such a method, the shape reproducibility of the mold is poor and the shape is likely to vary. The casting method is also a problem in that it is extremely inferior in productivity.
　本発明は、天然の歯牙に近い良好な切削感を有し、高効率な方法でも生産可能である歯科実習用模型歯と、当該歯科実習用模型歯を高効率で製造可能な歯科実習用模型歯の製造方法とを提供することを目的とする。 The present invention relates to a dental training model tooth that has a good cutting feeling close to that of natural teeth and can be produced by a highly efficient method, and a dental training model that can manufacture the dental training model tooth with high efficiency. It is an object of the present invention to provide a method for manufacturing a tooth.
　本発明者らは、象牙質部と、象牙質部に接合されるエナメル質部とを備える歯科実習用模型歯について、象牙質部及びエナメル質部に尿素樹脂を含む構成とすることにより、上記の課題を解決できることを見出し、本発明を完成するに至った。具体的に、本発明は以下のものを提供する。 The inventors of the present invention have a dental training model tooth including a dentin part and an enamel part joined to the dentin part, and the dentin part and the enamel part contain a urea resin, whereby The present inventors have found that the above problems can be solved and have completed the present invention. Specifically, the present invention provides the following.
　（１）　象牙質部とエナメル質部とを備え、前記象牙質部及び前記エナメル質部の少なくとも一方が尿素樹脂を含む、歯科実習用模型歯。 (1) A dental practice model tooth comprising a dentin part and an enamel part, wherein at least one of the dentin part and the enamel part contains a urea resin.
　（２）　前記象牙質部と前記エナメル質部とが継ぎ目なく一体化されており、前記象牙質部と前記エナメル質部とが同一の材料からなる、（１）に記載の歯科実習用模型歯。 (2) The dental training model tooth according to (1), wherein the dentin part and the enamel part are seamlessly integrated, and the dentin part and the enamel part are made of the same material. .
　（３）　象牙質部がエナメル質部に接合されている（１）に記載の歯科実習用模型歯。 (3) The dental training model tooth according to (1), wherein the dentin part is joined to the enamel part.
　（４）　象牙質部と、エナメル質部とが、互いに異なる材質からなる、（３）に記載の歯科実習用模型歯。 (4) The dental training model tooth according to (3), wherein the dentin part and the enamel part are made of different materials.
　（５）　象牙質部及びエナメル質部の少なくとも一方が、尿素樹脂と充填材とを含む、（１）～（４）のいずれか１つに記載の歯科実習用模型歯。 (5) The dental practice model tooth according to any one of (1) to (4), wherein at least one of the dentin part and the enamel part contains a urea resin and a filler.
　（６）　充填材が、Ｘ線造影性を有する充填材を含む、（５）に記載の歯科実習用模型歯。 (6) The dental training model tooth according to (5), wherein the filler includes a filler having X-ray contrast properties.
　（７）　象牙質部及びエナメル質部の少なくとも一方が着色剤を含む、（１）～（６）のいずれか１つに記載の歯科実習用模型歯。 (7) The dental practice model tooth according to any one of (1) to (6), wherein at least one of the dentin part and the enamel part contains a colorant.
　（８）　尿素樹脂又は尿素樹脂を含む組成物を用いる射出成形により、象牙質部とエナメル質部とを含み、象牙質部とエナメル質部とが継ぎ目なく一体化されている模型歯を形成する射出形成工程を含む、（２）、（５）、（６）、又は（７）に記載の歯科実習用模型歯の製造方法。 (8) Forming a model tooth including a dentin part and an enamel part, and the dentin part and the enamel part seamlessly integrated by injection molding using urea resin or a composition containing urea resin The manufacturing method of the model tooth for dental training as described in (2), (5), (6), or (7) including an injection molding process.
　（９）　尿素樹脂又は尿素樹脂を含む組成物を用いる射出成形により、象牙質部と、エナメル質部との少なくとも一方を形成する射出形成工程と、
　象牙質部と、エナメル質部とを接合する接合工程と、を含む（３）～（７）のいずれか１つに記載の歯科実習用模型歯の製造方法。 (9) An injection molding step of forming at least one of a dentin part and an enamel part by injection molding using a urea resin or a composition containing a urea resin;
A method for producing a dental tooth for dental training according to any one of (3) to (7), comprising a joining step of joining a dentin part and an enamel part.
　（１０）尿素樹脂又は尿素樹脂を含む組成物を用いる多層射出成形により、象牙質部と、エナメル質部とを、同一の金型内で、両者が接合された状態で別個に形成する、（３）～（７）のいずれか１つに記載の歯科実習用模型歯の製造方法。 (10) The dentin part and the enamel part are separately formed in the same mold in a state where both are joined by multilayer injection molding using a urea resin or a composition containing a urea resin. 3) A method for manufacturing a dental model tooth for dental training according to any one of (7) to (7).
　本発明によれば、天然の歯牙に近い良好な切削感を有し、高効率な方法でも生産可能である歯科実習用模型歯と、当該歯科実習用模型歯を高効率で製造可能な歯科実習用模型歯の製造方法とを提供することができる。 ADVANTAGE OF THE INVENTION According to this invention, the dental training model tooth which has a favorable cutting feeling close | similar to a natural tooth, and can be produced also by a highly efficient method, and the dental training which can manufacture the said dental training model tooth with high efficiency And a manufacturing method for a dental model tooth.
本発明に係る模型歯の断面を模式的に示す図である。It is a figure which shows typically the cross section of the model tooth which concerns on this invention.
≪模型歯≫
〔模型歯の全体構造〕
　以下、模型歯の全体構造について、図１を参照しながら説明する。本発明に係る模型歯１０は、エナメル質部１１と象牙質部１２とを備える。エナメル質部１１及び象牙質部１２の少なくとも一方は、尿素樹脂を含む。模型歯１０は、エナメル質部１１と象牙質部１２とを継ぎ目なく一体化して、単一のパーツとして形成されてもよい。また、エナメル質部１１が象牙質部１２の表面に密着するように、別個のパーツであるエナメル質部１１と象牙質部１２とが接合されて模型歯１０が構成されてもよい。 ≪Model tooth≫
[Overall structure of model teeth]
Hereinafter, the overall structure of the model tooth will be described with reference to FIG. A model tooth 10 according to the present invention includes an enamel portion 11 and a dentin portion 12. At least one of the enamel part 11 and the dentin part 12 contains a urea resin. The model tooth 10 may be formed as a single part by seamlessly integrating the enamel portion 11 and the dentin portion 12. Also, the model tooth 10 may be configured by joining the enamel part 11 and the dentin part 12, which are separate parts, so that the enamel part 11 is in close contact with the surface of the dentin part 12.
　エナメル質部１１及び象牙質部１２の形状は、所望する口腔内作業の練習が可能な形状であれば特に限定されない。通常、エナメル質部１１及び象牙質部１２の形状は、天然の歯牙を構成するエナメル質及び象牙質の形状を模した形状であるのが好ましい。
　特に、天然の歯牙に近い切削感を再現するために、エナメル質部１１の材料として、象牙質部１２の材料よりも硬い材料を採用している場合、エナメル質部１１の形状は、天然の歯牙におけるエナメル質の形状を模した形状であるのが好ましい。この場合、エナメル質部１１の最も厚い部分の厚さは、１～３ｍｍが好ましく、２～２．５ｍｍがより好ましい。 The shapes of the enamel portion 11 and the dentin portion 12 are not particularly limited as long as the shape of the desired intraoral work can be practiced. Usually, the shape of the enamel portion 11 and the dentin portion 12 is preferably a shape imitating the shapes of the enamel and the dentin constituting the natural tooth.
In particular, when a material harder than the material of the dentin portion 12 is adopted as the material of the enamel portion 11 in order to reproduce a cutting feeling close to natural teeth, the shape of the enamel portion 11 is natural. It is preferably a shape simulating the shape of enamel in the tooth. In this case, the thickness of the thickest portion of the enamel portion 11 is preferably 1 to 3 mm, and more preferably 2 to 2.5 mm.
　前述の通り、エナメル質部１１及び象牙質部１２の少なくとも一方は尿素樹脂を含む。エナメル質部１１及び象牙質部１２は、尿素樹脂のみで構成されてもよく、尿素樹脂と尿素樹脂以外の成分を含む尿素樹脂組成物で構成されてもよい。また、エナメル質部１１及び象牙質部１２の一方が尿素樹脂を含まない材料からなる場合、当該尿素樹脂を含まない材料は、従来から模型歯の材料として使用されている種々の材料から選択することができる。模型歯１０の材料が尿素樹脂組成物である場合、尿素樹脂組成物は、充填材、着色剤、及び尿素樹脂以外の樹脂成分や、紫外線吸収剤等の種々の添加剤を含んでいてもよい。尿素樹脂組成物に含まれるこれらの成分については後述する。 As described above, at least one of the enamel portion 11 and the dentin portion 12 contains a urea resin. The enamel part 11 and the dentin part 12 may be comprised only with urea resin, and may be comprised with the urea resin composition containing components other than urea resin and urea resin. When one of the enamel portion 11 and the dentin portion 12 is made of a material that does not contain a urea resin, the material that does not contain the urea resin is selected from various materials that have been conventionally used as model tooth materials. be able to. When the material of the model tooth 10 is a urea resin composition, the urea resin composition may contain various additives such as a filler, a colorant, a resin component other than the urea resin, and an ultraviolet absorber. . These components contained in the urea resin composition will be described later.
　エナメル質部１１の材質と、象牙質部１２の材質とは、同一であっても異なっていてもよい。模型歯１０の製造が容易であり、安価に模型歯１０を製造可能である点からは、エナメル質部１１の材質と、象牙質部１２の材質とが、同一の尿素樹脂又は尿素樹脂組成物であるのが好ましい。 The material of the enamel part 11 and the material of the dentin part 12 may be the same or different. From the viewpoint that the model tooth 10 can be easily manufactured and the model tooth 10 can be manufactured at low cost, the material of the enamel portion 11 and the material of the dentin portion 12 are the same urea resin or urea resin composition. Is preferred.
　この場合、特に製造が容易であることから、模型歯１０の構造として、エナメル質部１１と象牙質部１２とが継ぎ目なく一体化された、単一のパーツからなる構造であるのが好ましい。後述するように、尿素樹脂又は尿素樹脂組成物は、歯科治療において、治療対象の歯における切削された箇所の充填に用いられる充填用の樹脂材料（コンポジットレジン）との接着性に優れる。 In this case, since the manufacture is particularly easy, the structure of the model tooth 10 is preferably a structure composed of a single part in which the enamel portion 11 and the dentin portion 12 are seamlessly integrated. As will be described later, the urea resin or the urea resin composition is excellent in adhesiveness with a filling resin material (composite resin) used for filling a cut portion of a tooth to be treated in dental treatment.
　模型歯１０において、エナメル質部１１の材質と象牙質部１２の材質が、同一の材料である場合、天然の歯牙におけるエナメル質と象牙質との質感の差は表現できない。しかし、上記の理由から、エナメル質部１１及び象牙質部１２の材質として、同一の尿素樹脂又は尿素樹脂組成物を用いて製造された模型歯、特に、単一のパーツからなる模型歯は、コンポジットレジンを充填する作業の実習用の模型としては十分に有用なものである。 In the model tooth 10, when the material of the enamel portion 11 and the material of the dentin portion 12 are the same material, the difference in texture between the enamel and the dentin in the natural tooth cannot be expressed. However, for the above reasons, model teeth manufactured using the same urea resin or urea resin composition as the material of the enamel part 11 and the dentin part 12, in particular, model teeth made of a single part, It is a useful model as a training model for the work of filling a composite resin.
　また、天然の歯牙ではエナメル質と象牙質とで質感が異なっているため、より天然の歯牙に近い模型歯１０を製造する観点からは、エナメル質部１１の材質と、象牙質部１２の材質とが異なっているのが好ましい。この場合、エナメル質部１１の材質と、象牙質部１２の材質との一方が、尿素樹脂又は尿素樹脂組成物以外の材料であってもよいが、切削感の点や、上記のコンポジットレジンとの接着性の点等から、象牙質部１２が尿素樹脂又は尿素樹脂組成物からなるのが好ましい。 In addition, since the texture of enamel and dentin is different in natural teeth, the material of the enamel part 11 and the material of the dentin part 12 are used from the viewpoint of manufacturing the model tooth 10 closer to the natural tooth. Are preferably different from each other. In this case, one of the material of the enamel part 11 and the material of the dentin part 12 may be a material other than the urea resin or the urea resin composition. From the viewpoint of adhesiveness, etc., it is preferable that the dentin portion 12 is made of a urea resin or a urea resin composition.
　エナメル質は、象牙質よりも硬質な組織である。このため、エナメル質部１１は、象牙質部１２よりも高硬度に設計されるのが好ましい。象牙質部１２が尿素樹脂又は尿素樹脂組成物からなる場合、エナメル質部１１の材質は、尿素樹脂又は尿素樹脂組成物に限定されず、例えば、セラミックのような硬質の無機材料であってもよい。エナメル質部１１及び象牙質部１２の材質が、尿素樹脂組成物、又は尿素樹脂以外の樹脂を含む組成物である場合、エナメル質部１１及び象牙質部１２の硬度は、後述するように、エナメル質部１１及び象牙質部１２の材料である樹脂組成物に充填材を配合することで調整される。 Enamel is a harder tissue than dentin. For this reason, it is preferable that the enamel part 11 is designed to be harder than the dentin part 12. When the dentine part 12 consists of urea resin or a urea resin composition, the material of the enamel part 11 is not limited to a urea resin or a urea resin composition, For example, even if it is a hard inorganic material like a ceramic. Good. When the material of the enamel part 11 and the dentin part 12 is a urea resin composition or a composition containing a resin other than the urea resin, the hardness of the enamel part 11 and the dentin part 12 is as described later. It adjusts by mix | blending a filler with the resin composition which is the material of the enamel part 11 and the dentin part 12. FIG.
　象牙質部１２には、必要に応じて歯髄部１３が形成されていてもよい。なお、歯学的には、象牙質と歯髄とは異なる組織と認められるが、本願明細書では、歯髄部１３を象牙質部１２の一部として記載する。象牙質部１２は、歯髄部１３を備えるのが好ましい。象牙質部１２が歯髄部１３を備える場合、模型歯１０を用いて、髄質開拡、根管拡大、根管充填等の治療の練習を行いやすい。 A dental pulp portion 13 may be formed on the dentin portion 12 as necessary. In terms of dentistry, the dentin and the pulp are recognized as different tissues, but in the present specification, the pulp portion 13 is described as a part of the dentin portion 12. The dentin part 12 preferably includes a pulp part 13. In the case where the dentin portion 12 includes the pulp portion 13, it is easy to practice treatment such as medullary spread, root canal enlargement, root canal filling using the model tooth 10.
　象牙質部１２中に歯髄部１３を設ける方法としては、象牙質部１２中の歯髄部１３に相当する箇所を公知の方法に従って着色する方法が挙げられる。この場合、歯髄部１３の長さ方向に対して略平行な断面により２以上に分割された象牙質部１２の複数の部品を製造し、複数の部品中の分割面上の歯髄部１３に該当する箇所を象牙質部１２の色相とは異なる色相に着色した後に、複数の部品を接着剤等用いて接合して象牙質部１２を形成してもよい。 Examples of the method of providing the pulp portion 13 in the dentin portion 12 include a method of coloring a portion corresponding to the pulp portion 13 in the dentin portion 12 according to a known method. In this case, a plurality of parts of the dentin part 12 divided into two or more by a cross section substantially parallel to the length direction of the pulp part 13 is manufactured, and corresponds to the pulp part 13 on the divided surface in the plurality of parts. The portion to be processed may be colored with a hue different from the hue of the dentin portion 12, and then a plurality of parts may be joined using an adhesive or the like to form the dentin portion 12.
　象牙質部１２中に歯髄部１３を設ける別の方法としては、予め歯髄部１３に相当する形状の空孔を備える象牙質部１２を形成した後、当該空孔に歯髄部１３を構成する材料を充填する方法が挙げられる。歯髄部１３を構成する材料は、空孔に充填可能な材料であれば特に制限されない。歯髄部１３を構成する材料としては、充填時には流動性を有し充填後に硬化可能な硬化性樹脂が挙げられる。硬化性樹脂は、熱硬化性樹脂であっても光硬化性樹脂であってもよく、例えば、エポキシ樹脂、メラミン樹脂、尿素樹脂、アクリル樹脂、シリコーン樹脂等が挙げられる。 As another method of providing the pulp portion 13 in the dentin portion 12, a material that forms the pulp portion 13 in the hole after the dentin portion 12 having a hole having a shape corresponding to the pulp portion 13 is formed in advance. The method of filling is included. The material which comprises the dental pulp part 13 will not be restrict | limited especially if it is a material which can be filled with a void | hole. Examples of the material constituting the dental pulp portion 13 include a curable resin that has fluidity when filled and can be cured after filling. The curable resin may be a thermosetting resin or a photocurable resin, and examples thereof include an epoxy resin, a melamine resin, a urea resin, an acrylic resin, and a silicone resin.
　エナメル質部１１と象牙質部１２とが異なるパーツから構成される場合、エナメル質部１１と象牙質部１２とを接合させる方法は特に限定されない。例えば、エナメル質部１１と象牙質部１２とを物理的に嵌合させて両者を接合してもよい。また、接着剤を用いてエナメル質部１１と象牙質部１２とを接合してもよい。さらに、後述するように多色射出成型法を用いて、金型内でエナメル質部１１と象牙質部１２とを直接接合させてもよい。 When the enamel part 11 and the dentin part 12 are composed of different parts, the method for joining the enamel part 11 and the dentin part 12 is not particularly limited. For example, the enamel part 11 and the dentin part 12 may be physically fitted and joined together. Moreover, you may join the enamel part 11 and the dentin part 12 using an adhesive agent. Furthermore, as will be described later, the enamel portion 11 and the dentin portion 12 may be directly joined in a mold by using a multicolor injection molding method.
　以下、模型歯１０又は模型歯１０のパーツの材料について、尿素樹脂、充填材、無機材料、尿素樹脂以外の樹脂成分、着色剤、その他の添加剤、及び接着剤について順に説明する。 Hereinafter, the urea resin, the filler, the inorganic material, the resin component other than the urea resin, the colorant, other additives, and the adhesive will be described in order with respect to the material of the model tooth 10 or the model tooth 10 part.
〔尿素樹脂〕
　尿素樹脂は、尿素樹脂前駆体を熱硬化させて調製される。尿素樹脂前駆体の例としては、尿素とホルムアルデヒドとを含む混合物や、尿素とホルムアルデヒドとをある程度重合させたユリアホルムアルデヒド樹脂が挙げられる。尿素樹脂前駆体は、熱硬化の促進やホルムアルデヒドの損失の低減等の目的で、ホルムアルデヒド、ヘキサメチレンテトラミンや、シュウ酸ジメチルエステル、フタル酸無水物、有機ハロゲン化物、アミン塩酸塩、及びサリチル酸尿素アダクト等の硬化触媒を含んでいてもよい。 [Urea resin]
The urea resin is prepared by thermosetting a urea resin precursor. Examples of the urea resin precursor include a mixture containing urea and formaldehyde, and a urea formaldehyde resin obtained by polymerizing urea and formaldehyde to some extent. Urea resin precursors formaldehyde, hexamethylenetetramine, oxalic acid dimethyl ester, phthalic anhydride, organic halides, amine hydrochlorides, and salicylic acid urea adducts for the purpose of accelerating thermosetting and reducing loss of formaldehyde. A curing catalyst such as
　尿素樹脂前駆体としては、種々の成形体の製造に使用される尿素樹脂前駆体を特に制限なく使用することができる。また、尿素樹脂は、本発明の目的を阻害しない範囲で、公知の種々の方法で変性されたものであってもよい。 As the urea resin precursor, urea resin precursors used in the production of various molded products can be used without particular limitation. Further, the urea resin may be modified by various known methods within a range not impairing the object of the present invention.
　模型歯の材料として尿素樹脂又は尿素樹脂を含む尿素樹脂組成物を用いることによりは、エポキシ樹脂を用いて形成された模型歯に関する、切削感、長期保管時の変色に関する問題が解消された模型歯を製造することができる。 By using urea resin or urea resin composition containing urea resin as the material of the model tooth, the model tooth in which the problems related to cutting feeling and discoloration during long-term storage related to the model tooth formed using epoxy resin are solved. Can be manufactured.
　尿素樹脂前駆体としては、流動性を有し、射出成形に適用可能なものが好ましい。加熱された金型内に尿素樹脂前駆体が射出された後、金型内で尿素樹脂前駆体が硬化し、尿素樹脂を含むエナメル質部や象牙質部が形成される。射出成型に適用可能な尿素樹脂前駆体としては、例えば、それぞれ株式会社台和製である、リードライト（登録商標）ＷＴ－２０８６、リードライト（登録商標）タフアミンＩＮＴ２０６４Ｗ、リードライト（登録商標）Ｗ４２０、及びリードライト（登録商標）Ｙ２１２７等や、それぞれパナソニック株式会社製である、ＣＵ－Ｙ、ＣＵ－Ｅ、ＣＺ－Ｔ、及びＣＺ－Ｆ等が挙げられる。市販の尿素樹脂前駆体は、後述する充填材等の成分を配合して用いることもできる。 As the urea resin precursor, one having fluidity and applicable to injection molding is preferable. After the urea resin precursor is injected into the heated mold, the urea resin precursor is cured in the mold to form an enamel portion and a dentin portion containing the urea resin. Examples of urea resin precursors applicable to injection molding include, for example, Readwrite (registered trademark) WT-2086, Readwrite (registered trademark) Toughamine INT2064W, Readwrite (registered trademark) W420, manufactured by Taiwa Co., Ltd. And Readwrite (registered trademark) Y2127, and CU-Y, CU-E, CZ-T, and CZ-F manufactured by Panasonic Corporation. Commercially available urea resin precursors can also be used by blending components such as fillers described later.
　射出成型に適用可能な尿素樹脂前駆体を用いることにより、注型法と比較して顕著に高い効率で模型歯又は模型歯を構成するパーツを生産することができる。また、尿素樹脂前駆体を用いて射出成形法により模型歯を製造する場合、エポキシ樹脂を用いて注型法により模型歯を製造する場合の寸法精度、金型の形状の再現性、及びバリの発生等の問題が解消される。 By using a urea resin precursor applicable to injection molding, it is possible to produce model teeth or parts constituting the model teeth with significantly higher efficiency than the casting method. In addition, when manufacturing model teeth by injection molding using urea resin precursor, dimensional accuracy, mold shape reproducibility, and burr Problems such as occurrence are resolved.
〔充填材〕
　エナメル質部及び象牙質部を構成する材料は、模型歯の生産性の観点からは、充填材を含む尿素樹脂組成物であるのが好ましい。充填材を含む尿素樹脂組成物について、充填材の種類、含有量、及び充填材の形状等を適宜選択することにより、エナメル質部及び象牙質部の切削感を調整することができる。なお、エナメル質部又は象牙質部が、尿素樹脂以外の樹脂を含む樹脂組成物からなる場合、当該樹脂組成物は、尿素樹脂組成物と同様に、以下説明する充填材を含んでいてもよい。尿素樹脂以外の樹脂を含む樹脂組成物において、充填材の含有量は、尿素樹脂組成物と同様である。 [Filler]
The material constituting the enamel part and the dentin part is preferably a urea resin composition containing a filler from the viewpoint of model tooth productivity. About the urea resin composition containing a filler, the cutting feeling of an enamel part and a dentin part can be adjusted by selecting the kind of filler, content, the shape of a filler, etc. suitably. In addition, when an enamel part or a dentine part consists of resin compositions containing resin other than urea resin, the said resin composition may contain the filler demonstrated below similarly to a urea resin composition. . In the resin composition containing a resin other than the urea resin, the content of the filler is the same as that of the urea resin composition.
　充填材としては、従来から種々の樹脂組成物に配合されている、有機又は無機の充填材を用いることができる。充填材の形状は特に限定されず、例えば、繊維状の充填材や、粉状又は板状の充填材を用いることができる。尿素樹脂組成物は、充填材を２種以上組み合わせて含んでいてもよい。 As the filler, organic or inorganic fillers conventionally blended in various resin compositions can be used. The shape of the filler is not particularly limited, and for example, a fibrous filler or a powdery or plate-like filler can be used. The urea resin composition may contain a combination of two or more fillers.
　繊維状の充填材としては、ガラス繊維、ミルドガラス繊維、炭素繊維、セルロース繊維、セラミック繊維、ジルコニア繊維、シリカ繊維、酸化チタン繊維、炭化ケイ素繊維、ロックウール、チタン酸カリウムウィスカ、チタン酸バリウムウィスカ、ホウ酸アルミニウムウィスカ、及び金属繊維等が挙げられる。
　粉状又は板状の充填材としては、シリカ、マイカ、タルク、カオリン、炭酸カルシウム、ガラスビーズ、ガラスフレーク、バリウムガラス、ジルコニウムガラス、酸化ジルコニウム、ケイ酸ジルコニウム、硫酸バリウム、クレー、ワラストナイト、アルミナ、酸化亜鉛、酸化チタン、酸化マグネシウム、及びグラファイト等が挙げられる。 Examples of the fibrous filler include glass fiber, milled glass fiber, carbon fiber, cellulose fiber, ceramic fiber, zirconia fiber, silica fiber, titanium oxide fiber, silicon carbide fiber, rock wool, potassium titanate whisker, and barium titanate whisker. , Aluminum borate whiskers, and metal fibers.
As powder or plate-like filler, silica, mica, talc, kaolin, calcium carbonate, glass beads, glass flakes, barium glass, zirconium glass, zirconium oxide, zirconium silicate, barium sulfate, clay, wollastonite, Examples include alumina, zinc oxide, titanium oxide, magnesium oxide, and graphite.
　以上説明した充填材の中では、模型歯の切削感を天然歯牙の切削感に近づけることが容易であることから、酸化チタン、セルロース繊維、ガラス繊維、シリカ、及びバリウムガラスが好ましく、シリカ、及びバリウムガラスがより好ましく、シリカが特に好ましい。 Among the fillers described above, titanium oxide, cellulose fiber, glass fiber, silica, and barium glass are preferred because it is easy to bring the cutting feeling of model teeth close to the cutting feeling of natural teeth, silica, and Barium glass is more preferred, and silica is particularly preferred.
　なお、配合する充填材は尿素樹脂とのなじみや濡れ性を改善するために、予め表面処理を施されていることが好ましい。好ましい表面処理材としては、シラン系カップリング剤、チタネート系カップリング剤、アルミネート系カップリング剤、及びジルコネート系カップリング剤等が挙げられる。表面処理剤の使用量は、充填材の比表面積に応じて適宜調整される。尿素樹脂と表面処理を施された充填材からなる複合樹脂はエナメル質部と象牙質部に成型される。このようにして製作されたエナメル質部と象牙質部は、硬度、引張強度、耐衝撃性等が向上する。 In addition, it is preferable that the filler to be blended is subjected to a surface treatment in advance in order to improve the familiarity and wettability with the urea resin. Preferred surface treatment materials include silane coupling agents, titanate coupling agents, aluminate coupling agents, zirconate coupling agents, and the like. The usage-amount of a surface treating agent is suitably adjusted according to the specific surface area of a filler. A composite resin comprising a urea resin and a surface-treated filler is molded into an enamel part and a dentin part. The enamel part and the dentin part thus produced have improved hardness, tensile strength, impact resistance and the like.
　また、充填材としては、切削感を調整しつつ模型歯にＸ線造影性を付与できることからＸ線造影性を有する充填材も好ましい。Ｘ線造影性を有する充填材の好適な例としては、バリウムガラス、ジルコニウムガラス、酸化ジルコニウム、酸化バリウム、ケイ酸ジルコニウム、及び硫酸バリウムが挙げられる。これらの中では、Ｘ線造影性の点から、酸化ジルコニウムが好ましい。 Also, as the filler, a filler having an X-ray contrast property is preferable because the X-ray contrast property can be imparted to the model tooth while adjusting the cutting feeling. Preferable examples of the filler having X-ray contrast properties include barium glass, zirconium glass, zirconium oxide, barium oxide, zirconium silicate, and barium sulfate. Among these, zirconium oxide is preferable from the viewpoint of X-ray contrast properties.
　Ｘ線造影性を有する充填材の使用量は特に限定されず、典型的には、尿素樹脂組成物の質量に対して、１～８０質量％が好ましい。模型歯のＸ線造影性と、成形性とを両立させる点からは、Ｘ線造影性を有する充填材の使用量は、尿素樹脂組成物の質量に対して、１～２０質量％が好ましく、３～１５質量％がより好ましく、３～１０質量％が特に好ましい。
　なお、Ｘ線造影性のみを考慮すると、Ｘ線造影性を有する充填材が酸化ジルコニウム、酸化バリウム、ケイ酸ジルコニウム、及び硫酸バリウム等である場合、Ｘ線造影性を有する充填材の使用量は、尿素樹脂組成物の質量に対して、１～３０質量％が好ましく、３～２０質量％がより好ましく、５～１５質量が特に好ましい。
　Ｘ潜造影性を有する充填材がバリウムガラスやジルコニアガラス等のガラス成分である場合、Ｘ線造影性を有する充填材の使用量は、尿素樹脂組成物の質量に対して、２０～８０質量％が好ましく、３０～７０質量％がより好ましく、４０～６０質量％が特に好ましい。 The amount of the filler having X-ray contrast properties is not particularly limited, and is typically preferably 1 to 80% by mass with respect to the mass of the urea resin composition. From the viewpoint of achieving both X-ray contrast properties and moldability of the model teeth, the amount of the filler having X-ray contrast properties is preferably 1 to 20% by mass with respect to the mass of the urea resin composition. 3 to 15% by mass is more preferable, and 3 to 10% by mass is particularly preferable.
In consideration of only X-ray contrast, if the filler having X-ray contrast is zirconium oxide, barium oxide, zirconium silicate, barium sulfate, etc., the amount of filler having X-ray contrast is The amount of the urea resin composition is preferably 1 to 30% by mass, more preferably 3 to 20% by mass, and particularly preferably 5 to 15% by mass.
When the filler having X latent contrast is a glass component such as barium glass or zirconia glass, the amount of filler having X contrast is 20 to 80% by mass with respect to the mass of the urea resin composition. 30 to 70% by mass is more preferable, and 40 to 60% by mass is particularly preferable.
　Ｘ線造影性を有する充填材は、例えば、第一稀元素化学工業株式会社、キンセイマテック株式会社、日本フリット株式会社、及びＮＥＣ　ＳＣＨＯＴＴ　コンポーネンツ株式会社等から販売されているものを用いることができる。 As the filler having X-ray contrast properties, for example, those sold by Daiichi Rare Element Chemical Co., Ltd., Kinsei Matec Co., Ltd., Nippon Frit Co., Ltd., NEC SCHOTT Components Co., Ltd., or the like can be used.
　エナメル質部及び象牙質部を構成する尿素樹脂組成物に、以上説明した充填材を配合することで、バー、リーマ、ファイル等の歯科治療用の工具を用いてエナメル質部及び象牙質部を切削する際の切削感が調整される。エナメル質部及び象牙質部の切削感は、充填材の種類によっても異なるが、概ね、エナメル質部及び象牙質部の材質のビッカース硬度を調整することで調製される。 By blending the above-described fillers with the urea resin composition that constitutes the enamel part and the dentin part, the enamel part and the dentin part can be formed using dental treatment tools such as bars, reamers, and files. The feeling of cutting when cutting is adjusted. The cutting feeling of the enamel part and the dentin part varies depending on the type of filler, but is generally prepared by adjusting the Vickers hardness of the material of the enamel part and the dentin part.
　一般的には、尿素樹脂組成物中の充填材の含有量が多い程、尿素樹脂組成物を用いて形成されるエナメル質部及び象牙質部のビッカース硬度が高い。また、充填材が同一の素材である場合において、充填材のサイズが大きい程、エナメル質部及び象牙質部のビッカース硬度が高い。充填材のサイズが大きいとは、粉状又は板状の充填材については、充填材の平均粒子径が大きいことを意味し、繊維状の充填材については、充填材の繊維長及び繊維径の少なくとも一方が大きいことを意味する。 Generally, the greater the filler content in the urea resin composition, the higher the Vickers hardness of the enamel part and dentin part formed using the urea resin composition. When the filler is the same material, the larger the filler size, the higher the Vickers hardness of the enamel part and the dentin part. The large size of the filler means that the average particle diameter of the filler is large for the powdery or plate-like filler, and the fiber length and the fiber diameter of the filler for the fibrous filler. It means that at least one is large.
　天然の歯牙に近い切削感を有する模型歯を製造するためには、エナメル質部のビッカース硬度が天然の歯牙同様２００～４００程度であるのが好ましい。しかし、樹脂組成物を用いてエナメル質部を形成する場合、良好な成形性を維持しつつ、２００～４００程度のビッカース硬度を実現することは困難である。そこで、エナメル質部を充填材を含む尿素樹脂組成物のような樹脂組成物を用いて形成する場合、天然の歯牙に近い良好な切削感と、模型歯の良好な生産性とを両立させる観点から、エナメル質部の材質のビッカース硬度は、４０～２００であるのが好ましく、４０～１５０であってもよく、４０～１００であってもよい。 In order to produce a model tooth having a cutting feeling close to that of a natural tooth, it is preferable that the Vickers hardness of the enamel portion is about 200 to 400 like a natural tooth. However, when the enamel portion is formed using the resin composition, it is difficult to achieve a Vickers hardness of about 200 to 400 while maintaining good moldability. Therefore, when the enamel part is formed using a resin composition such as a urea resin composition containing a filler, a viewpoint of achieving both good cutting feeling close to natural teeth and good productivity of model teeth. Therefore, the Vickers hardness of the material of the enamel part is preferably 40 to 200, 40 to 150, or 40 to 100.
　また、天然の歯牙に近い切削感を有する模型歯を製造するためには、象牙質部の材質のビッカース硬度は、エナメル質部の材質のビッカース硬度より低い値に調整されるのが好ましい。 Further, in order to manufacture a model tooth having a cutting feeling close to that of a natural tooth, it is preferable that the Vickers hardness of the dentin portion material is adjusted to a value lower than the Vickers hardness of the enamel portion material.
　エナメル質部及び象牙質物のビッカース硬度を調整する際の、尿素樹脂組成物中の充填材の配合量は、エナメル質部及び象牙質物のビッカース硬度が所望する値である限り特に限定されない。典型的には、充填材の配合量は、尿素樹脂組成物の質量に対して、１～５０質量％が好ましく、５～４０質量％がより好ましく、１０～４０質量％が特に好ましい。 The blending amount of the filler in the urea resin composition when adjusting the Vickers hardness of the enamel part and the dentin is not particularly limited as long as the Vickers hardness of the enamel part and the dentin is a desired value. Typically, the blending amount of the filler is preferably 1 to 50% by mass, more preferably 5 to 40% by mass, and particularly preferably 10 to 40% by mass with respect to the mass of the urea resin composition.
　以上、尿素樹脂組成物に配合される充填材と、充填材と模型歯の切削感との関係について説明したが、天然の歯牙に近い切削感の模型歯を形成できる点で、充填材としてはシリカ及びバリウムガラスが好ましく、シリカがより好ましい。 As described above, the filler blended in the urea resin composition and the relationship between the filler and the cutting feeling of the model teeth have been described, but as a filler, it is possible to form a model tooth with a cutting feeling close to natural teeth. Silica and barium glass are preferred, and silica is more preferred.
　充填材がシリカである場合、例えば、尿素樹脂組成物の質量に対して５～５０質量％、好ましくは２０～４０質量％のシリカを含む尿素樹脂組成物を用いることにより、天然の歯牙が備えるエナメル質の切削感に極めて近い切削感を有するエナメル質部を形成することができる。 When the filler is silica, for example, natural teeth are provided by using a urea resin composition containing 5 to 50% by mass, preferably 20 to 40% by mass of silica, based on the mass of the urea resin composition. An enamel portion having a cutting feeling very close to that of enamel can be formed.
〔無機材料〕
　前述のように、天然の歯牙に近い切削感を有する模型歯を作成するためには、エナメル質部の材料として硬質の無機材料を用いてもよい。このような、硬質の無機材料としては、例えば、セラミックが挙げられる。セラミックの種類としては、従来から、模型歯の材料として使用されていたものであれば特に限定されない。 [Inorganic materials]
As described above, a hard inorganic material may be used as a material for the enamel portion in order to create a model tooth having a cutting feeling close to that of a natural tooth. Examples of such a hard inorganic material include ceramic. The type of ceramic is not particularly limited as long as it is conventionally used as a model tooth material.
　無機材料からなるエナメル質部を製造する方法特に限定されない。無機材料からなるエナメル質部は、材料に合わせた周知の加工方法を用いて製造される。 The method for producing an enamel part made of an inorganic material is not particularly limited. The enamel portion made of an inorganic material is manufactured using a known processing method according to the material.
　エナメル質部を硬質の無機材料を用いて製造する場合、天然の歯牙に近い切削感を有する模型歯を製造するためには、エナメル質部の材質のビッカース硬度は、好ましくは２００～４２０、より好ましくは２５０～３８０、特に好ましくは２７０～３７０の範囲である。 When the enamel part is manufactured using a hard inorganic material, the Vickers hardness of the material of the enamel part is preferably 200 to 420, in order to manufacture a model tooth having a cutting feeling close to that of a natural tooth. The range is preferably 250 to 380, particularly preferably 270 to 370.
〔尿素樹脂以外の樹脂成分〕
　エナメル質部及び象牙質部を構成する材料が尿素樹脂組成物である場合、本発明の目的を阻害しない範囲で、尿素樹脂に加えて尿素樹脂以外の樹脂成分を含んでいてもよい。尿素樹脂以外の樹脂成分は、熱可塑性樹脂であっても、熱硬化性樹脂であってもよい。尿素樹脂以外の樹脂成分は、模型歯の切削感の点から、熱硬化性樹脂であるのが好ましい。尿素樹脂組成物に含まれる尿素樹脂以外の樹脂成分が熱硬化性樹脂である場合、模型歯を切削する際に工具と模型歯との摩擦で生じる摩擦熱による模型歯の軟化が生じにくいため、天然の歯牙に近い切削感を有する模型歯を得やすい。 [Resin components other than urea resin]
When the material constituting the enamel part and the dentin part is a urea resin composition, a resin component other than the urea resin may be included in addition to the urea resin as long as the object of the present invention is not impaired. The resin component other than the urea resin may be a thermoplastic resin or a thermosetting resin. The resin component other than the urea resin is preferably a thermosetting resin from the viewpoint of cutting feeling of the model teeth. When the resin component other than the urea resin contained in the urea resin composition is a thermosetting resin, softening of the model teeth due to frictional heat generated by friction between the tool and the model teeth is difficult when cutting the model teeth. It is easy to obtain model teeth that have a cutting feeling similar to natural teeth.
　尿素樹脂組成物が尿素樹脂以外の樹脂成分を含む場合、尿素樹脂と、尿素樹脂以外の樹脂成分とは均一に相溶化していてもよく、尿素樹脂と尿素樹脂以外の樹脂成分とのどちらか一方が海成分であり他方が島成分である海島構造を形成してもよい。 When the urea resin composition includes a resin component other than the urea resin, the urea resin and the resin component other than the urea resin may be compatible with each other, and either the urea resin or the resin component other than the urea resin may be used. A sea-island structure in which one is a sea component and the other is an island component may be formed.
　尿素樹脂以外の樹脂成分が熱可塑性樹脂である場合の好適な例としては、ポリアセタール樹脂、ポリアミド樹脂、ポリカーボネート樹脂、ポリエステル樹脂（ポリブチレンテレフタレート、ポリエチレンテレフタレート、ポリアリレート等）、ＦＲ－ＡＳ樹脂、ＦＲ－ＡＢＳ樹脂、ＡＳ樹脂、ＡＢＳ樹脂、ポリフェニレンオキサイド樹脂、ポリフェニレンサルファイド樹脂、ポリスルホン樹脂、ポリエーテルスルホン樹脂、ポリエーテルエーテルケトン樹脂、フッ素系樹脂、ポリイミド樹脂、ポリアミドイミド樹脂、ポリアミドビスマレイミド樹脂、ポリエーテルイミド樹脂、ポリベンゾオキサゾール樹脂、ポリベンゾチアゾール樹脂、ポリベンゾイミダゾール樹脂、ＢＴ樹脂、ポリメチルペンテン、超高分子量ポリエチレン、ＦＲ－ポリプロピレン、（メタ）アクリル樹脂（ポリメチルメタクリレート等）、及びポリスチレン等が挙げられる。 Preferable examples when the resin component other than the urea resin is a thermoplastic resin include polyacetal resin, polyamide resin, polycarbonate resin, polyester resin (polybutylene terephthalate, polyethylene terephthalate, polyarylate, etc.), FR-AS resin, FR -ABS resin, AS resin, ABS resin, polyphenylene oxide resin, polyphenylene sulfide resin, polysulfone resin, polyethersulfone resin, polyetheretherketone resin, fluorine resin, polyimide resin, polyamideimide resin, polyamide bismaleimide resin, polyether Imide resin, polybenzoxazole resin, polybenzothiazole resin, polybenzimidazole resin, BT resin, polymethylpentene, ultrahigh molecular weight polyethylene, FR-poly Propylene, (meth) acrylic resin (polymethyl methacrylate, etc.), and polystyrene, and the like.
　尿素樹脂以外の樹脂成分が熱硬化性樹脂である場合の好適な例としては、フェノール樹脂、メラミン樹脂、エポキシ樹脂、及びアルキド樹脂等が挙げられる。 Preferable examples when the resin component other than the urea resin is a thermosetting resin include a phenol resin, a melamine resin, an epoxy resin, and an alkyd resin.
　エナメル質部及び象牙質部を構成する材料が、尿素樹脂以外の樹脂成分を含む尿素樹脂組成物である場合、尿素樹脂組成物に含まれる樹脂成分中の尿素樹脂の含有量は、５０質量％以上が好ましく、７０質量％以上がより好ましく、９０質量％以上が特に好ましく、９５質量％以上が最も好ましい。 When the material constituting the enamel part and the dentin part is a urea resin composition containing a resin component other than the urea resin, the content of the urea resin in the resin component contained in the urea resin composition is 50% by mass. The above is preferable, 70% by mass or more is more preferable, 90% by mass or more is particularly preferable, and 95% by mass or more is most preferable.
〔着色剤〕
　エナメル質部及び象牙質部は、透明であっても着色されていてもよい。また、エナメル質部及び象牙質部の一方のみが着色されていてもよい。エナメル質部及び象牙質部の双方が着色されているのが好ましく、この場合、エナメル質部及び象牙質部は、天然の歯牙の色相に近い色相に着色されるのが好ましい。
　天然の歯牙に近い色相の具体例としては、白色、アイボリー、乳白色、Ａ２色、及びＡ３色等が挙げられる。これらの色相は、半透明色であってもよい。 [Colorant]
The enamel part and the dentin part may be transparent or colored. Further, only one of the enamel part and the dentin part may be colored. It is preferable that both the enamel part and the dentin part are colored. In this case, the enamel part and the dentin part are preferably colored with a hue close to the hue of a natural tooth.
Specific examples of hues close to natural teeth include white, ivory, milky white, A2 color, and A3 color. These hues may be translucent.
　エナメル質部及び象牙質部の双方が、天然の歯牙の色相に近い色相に着色されている場合、模型歯を用いる実習時に、天然の歯牙に対する作業と同様の感覚で作業を行うことができる利点がある。
　象牙質部が透明である場合、象牙質部は着色された歯髄部を備えるのが好ましい。この場合、模型歯を用いる実習時に、歯髄部の視認性が良好である利点がある。 When both the enamel part and the dentin part are colored with a hue close to the hue of natural teeth, it is possible to work with the same feeling as the work on natural teeth during training using model teeth There is.
When the dentin part is transparent, the dentin part preferably comprises a colored pulp part. In this case, there is an advantage that the visibility of the dental pulp portion is good during the practice using the model teeth.
　着色剤としては、エナメル質部及び象牙質部を所望する色相に着色可能であり、成形時の加熱によって変色や退色を起こさないものであれば特に限定されず、公知の種々の着色剤を用いることができる。 The colorant is not particularly limited as long as it can color the enamel part and the dentin part to a desired hue and does not cause discoloration or fading by heating during molding. Various known colorants are used. be able to.
　好ましい着色剤としては、例えば、イエローオーカー、ベンガラ、群青、黒酸化鉄、チタンホワイト（二酸化チタン）等の顔料が挙げられる。 Preferred examples of the colorant include pigments such as yellow ocher, bengara, ultramarine blue, black iron oxide, and titanium white (titanium dioxide).
　着色剤の使用量は特に限定されない。着色剤は、エナメル質部又は象牙質部が、所望する色相及び透明性になるような量で用いられる。 The amount of colorant used is not particularly limited. The colorant is used in an amount such that the enamel part or dentin part has the desired hue and transparency.
　なお、エナメル質部及び象牙質部を構成する材料に対して、所望する色相の塗料でペイントを施してもよい。この場合、塗膜の厚さは、模型歯の切削感を損なわないように極力薄いのが好ましい。 In addition, you may paint with the paint of a desired hue with respect to the material which comprises an enamel part and a dentin part. In this case, the thickness of the coating film is preferably as thin as possible so as not to impair the cutting feeling of the model teeth.
〔その他の添加剤〕
　エナメル質部及び象牙質部を構成する材料は、上記の、充填材、尿素樹脂以外の樹脂成分、及び着色剤の他に、種々の添加剤を含んでいてもよい。好適な添加剤としては、例えば、酸化防止剤、紫外線吸収剤、離型剤、可塑剤等が挙げられる。 [Other additives]
The material constituting the enamel part and the dentin part may contain various additives in addition to the filler, the resin component other than the urea resin, and the colorant. Suitable additives include, for example, antioxidants, ultraviolet absorbers, mold release agents, plasticizers and the like.
〔接着剤〕
　エナメル質部と象牙質部と接着剤を用いて接合する場合、接着剤の種類は、エナメル質部と象牙質部とを良好に接合できる限り特に限定されない。接着剤としては、ラジカル重合型接着剤や、カチオン重合型やアニオン重合型等のイオン重合型接着剤や、メラミン・ユリア共縮合樹脂接着剤、エポキシ系接着剤等種々の接着剤を用いることができる。 〔adhesive〕
When joining an enamel part, a dentin part, and an adhesive agent, the kind of adhesive agent will not be specifically limited as long as an enamel part and a dentin part can be favorably joined. As the adhesive, various types of adhesives such as radical polymerization type adhesives, ion polymerization type adhesives such as cationic polymerization type and anion polymerization type, melamine / urea co-condensation resin adhesives, epoxy adhesives, etc. may be used. it can.
　かかる接着剤の中では、酸素阻害を受けることなく速やか且つ良好に硬化してエナメル質部と象牙質部とを強固に接着可能であることと、接着時の接着剤の白化が生じにくいこととから、光硬化性のアニオン重合型の接着剤が好ましい。光硬化性のアニオン重合型の接着剤としては、例えば、２－シアノアクリル酸エステルと光開始剤とを含む光硬化性の瞬間接着剤が挙げられる。 Among such adhesives, it is possible to cure quickly and satisfactorily without being obstructed by oxygen and to firmly bond the enamel part and the dentin part, and the whitening of the adhesive during bonding is less likely to occur. Therefore, a photocurable anionic polymerization type adhesive is preferable. Examples of the photocurable anionic polymerization type adhesive include a photocurable instantaneous adhesive containing 2-cyanoacrylate and a photoinitiator.
　メラミン樹脂又はメラミン樹脂組成物は、光硬化性のアニオン重合型の接着剤に対する接着性に劣る。他方、尿素樹脂又は尿素樹脂組成物は、光硬化性のアニオン重合型の接着剤に対する接着性が良好である。このため、光硬化性のアニオン重合型の接着剤を用いると、それぞれ尿素樹脂を含むエナメル質部と象牙質部とが特に良好に接着される。 The melamine resin or melamine resin composition is inferior in adhesiveness to a photocurable anionic polymerization type adhesive. On the other hand, the urea resin or urea resin composition has good adhesion to a photocurable anionic polymerization type adhesive. For this reason, when a photocurable anionic polymerization type adhesive is used, the enamel portion and the dentin portion each containing a urea resin are particularly well bonded.
　以上説明した材料を用いて形成されるエナメル質部と象牙質部を接合することによって、本発明に係る模型歯が得られる。 The model tooth according to the present invention is obtained by joining the enamel portion and the dentin portion formed using the materials described above.
　なお、接着剤を用いて接合されるパーツの接合面は、例えば、サンドブラストやケミカルエッチング等の方法によって粗面化されていてもよい。接着を行う前に、接着面を粗面化することにより、より強固に模型歯のパーツを接合することができる。 In addition, the joint surface of the parts joined using the adhesive may be roughened by a method such as sand blasting or chemical etching. By roughening the bonding surface before bonding, the model tooth parts can be bonded more firmly.
≪模型歯の製造方法≫
　本発明に係る模型歯を製造する方法は特に限定されず、尿素樹脂に適用される種々の成形方法を採用することができる。模型歯を構成するエナメル質部及び象牙質部の製造方法の具体例としては、尿素樹脂前駆体を所望の形状の金型に注型した後に加熱して硬化させる注型法、圧縮成形法、及び射出成形等が挙げられる。これらの方法の中では、模型歯の生産性が良好であることから射出成型法が好ましい。 ≪Model tooth manufacturing method≫
The method for producing the model tooth according to the present invention is not particularly limited, and various molding methods applied to the urea resin can be employed. As a specific example of the manufacturing method of the enamel part and the dentin part constituting the model tooth, a casting method in which a urea resin precursor is cast into a mold having a desired shape and then cured by heating, a compression molding method, And injection molding. Among these methods, the injection molding method is preferable because the productivity of the model teeth is good.
　射出成形法において用いる射出成形機としては、従来から尿素樹脂の射出成形に用いられているものを特に制限なく使用することができる。射出成形により製造されるエナメル質部及び象牙質部を接合することにより、模型歯が得られる。エナメル質部及び象牙質部を接合する場合、好ましくは前述の接着剤が使用される。
　なお、エナメル質部及び象牙質部は、それぞれ２以上に分割されたパーツとして製造されてもよい。この場合、分割されたパーツを接合して、エナメル質部及び象牙質部が形成される。 As an injection molding machine used in the injection molding method, those conventionally used for urea resin injection molding can be used without particular limitation. A model tooth is obtained by joining the enamel part and the dentin part produced by injection molding. When joining an enamel part and a dentin part, Preferably the above-mentioned adhesive agent is used.
The enamel part and the dentin part may be manufactured as parts divided into two or more. In this case, the divided parts are joined to form an enamel part and a dentin part.
　射出成形装置の具体例としては、ＥＣ－６０（株式会社東芝製、最大射出圧力２４５０Ｋｇ／ｃｍ２、型締力６０ｔｏｎ）が挙げられる。ＥＣ－６０を用いて尿素樹脂前駆体を射出成形する際の好ましい条件は以下の通りである。
金型温度：固定側１４５～１６０℃、可動側１４５～１６０℃
シリンダー温度：前部８０～１００℃、後部４０～７０℃
射出圧力：６０～１４０ＭＰａ
スクリュー回転数：３０～６０ｒｐｍ
硬化時間：２０～４０秒 A specific example of the injection molding apparatus is EC-60 (manufactured by Toshiba Corporation, maximum injection pressure 2450 kg / cm 2 , mold clamping force 60 ton). Preferred conditions for injection molding of the urea resin precursor using EC-60 are as follows.
Mold temperature: 145 to 160 ° C on the fixed side, 145 to 160 ° C on the movable side
Cylinder temperature: front 80-100 ° C, rear 40-70 ° C
Injection pressure: 60-140 MPa
Screw rotation speed: 30-60rpm
Curing time: 20-40 seconds
　また、模型歯の製造には多層射出成形法を適用することもできる。多層射出成形法では、エナメル質部と、象牙質部とが、同一の金型内で、両者が接合された状態で形成される。この方法によれば、エナメル質部と象牙質部とを接合する作業が不要であるため、特に模型歯の生産性が良好である。 Also, a multilayer injection molding method can be applied to the manufacture of model teeth. In the multilayer injection molding method, the enamel portion and the dentin portion are formed in a state where both are joined in the same mold. According to this method, since the work of joining the enamel part and the dentin part is unnecessary, the productivity of the model tooth is particularly good.
　以下、実施例に基づいて本発明を詳細に説明するが、本発明はこれらの実施例によって限定されるものではない。 Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limited to these examples.
［実施例１］
　下記組成の尿素樹脂前駆体Ｉと、天然の歯牙が備えるエナメル質を模した形状の空洞部を有する金型とを用いて下記の条件で射出成形を行い、エナメル質部を得た。
＜尿素樹脂前駆体Ｉ＞
　ユリアホルムアルデヒド樹脂（リードライト（登録商標）ＷＴ－２０８６、株式会社台和製）：７０質量部
　セルロース：２２質量部
　酸化ジルコニウム：５質量部
　チタンホワイト：３質量部
　ホルムアルデヒド：１質量部
　ヘキサメチレンテトラミン：１質量部
＜射出成形条件＞
装置：ＥＣ－６０（株式会社東芝製、最大射出圧力２４５０Ｋｇ／ｃｍ２、型締力６０ｔｏｎ）
金型温度：固定側１４５～１６０℃、可動側１４５～１６０℃
シリンダー温度：前部８０～１００℃、後部４０～７０℃
射出圧力：６０～１４０ＭＰａ
スクリュー回転数：３０～６０ｒｐｍ
硬化時間：２０～４０秒 [Example 1]
Using the urea resin precursor I having the following composition and a mold having a hollow portion shaped like an enamel provided in natural teeth, injection molding was performed under the following conditions to obtain an enamel portion.
<Urea resin precursor I>
Urea formaldehyde resin (Readlight (registered trademark) WT-2086, manufactured by Taiwa Co., Ltd.): 70 parts by mass Cellulose: 22 parts by mass Zirconium oxide: 5 parts by mass Titanium white: 3 parts by mass Formaldehyde: 1 part by mass Hexamethylenetetramine: 1 Mass <Injection molding conditions>
Apparatus: EC-60 (manufactured by Toshiba Corporation, maximum injection pressure 2450Kg / cm 2 , mold clamping force 60ton)
Mold temperature: 145 to 160 ° C on the fixed side, 145 to 160 ° C on the movable side
Cylinder temperature: front 80-100 ° C, rear 40-70 ° C
Injection pressure: 60-140 MPa
Screw rotation speed: 30-60rpm
Curing time: 20-40 seconds
　下記組成の尿素樹脂前駆体ＩＩと、天然の歯牙が備える象牙質を模した形状の空洞部を有する金型とを用いて上記の条件で射出成形を行い、象牙質部を得た。なお、象牙質部は２つに分割されたパーツとして製造した。分割された２つのパーツの歯髄部に該当する箇所を着色した後、２つのパーツを接着剤（ＴＢ１７７３Ｅ、株式会社スリーボンド製、アニオン重合による光硬化付与瞬間接着剤）を用いて接着して象牙質部を形成した。なお、接着剤としては、ラジカル重合型の瞬間接着剤（例えば、株式会社アルテコ製のＶ２等）や、メラミン・ユリア共縮合樹脂接着剤等、種々の接着剤も用いることができる。
＜尿素樹脂前駆体ＩＩ＞
　変性ユリアホルムアルデヒド樹脂（リードライト（登録商標）タフアミンＩＮＴ２０６４Ｗ、株式会社台和製）：７０質量部
　セルロース：２２質量部
　酸化ジルコニウム：５質量部
　チタンホワイト：１質量部
　ホルムアルデヒド：１質量部
　ヘキサメチレンテトラミン：１質量部 Injection molding was performed under the above conditions using a urea resin precursor II having the following composition and a mold having a cavity shaped like a dentin included in a natural tooth to obtain a dentin part. The dentin part was manufactured as a part divided into two parts. After coloring the part corresponding to the pulp part of the two divided parts, the two parts are bonded by using an adhesive (TB1773E, manufactured by ThreeBond Co., Ltd., an anionic polymerization photocuring instant adhesive) and dentin Part was formed. Various adhesives such as radical polymerization type instantaneous adhesive (for example, V2 manufactured by Arteco Co., Ltd.) and melamine / urea co-condensation resin adhesive can be used as the adhesive.
<Urea resin precursor II>
Modified urea formaldehyde resin (Readlight (registered trademark) Toughamine INT2064W, manufactured by Taiwa Corporation): 70 parts by weight Cellulose: 22 parts by weight Zirconium oxide: 5 parts by weight Titanium white: 1 part by weight Formaldehyde: 1 part by weight Hexamethylenetetramine: 1 Parts by mass
　得られたエナメル質部と象牙質部とを、接着剤（ＴＢ１７７３Ｅ、株式会社スリーボンド製、アニオン重合による光硬化付与瞬間接着剤）を用いて接合して模型歯を得た。エナメル質部と象牙質部とは容易には剥離せず、エナメル質部と象牙質部との接着剤による接着性は良好であった。
　また、得られた模型歯の一部を切削し、模型歯に凹部を形成した後、アクリル樹脂系のコンポジットレジンを形成された凹部に充填・硬化させた。コンポジットレジンを硬化させた後、コンポジットレジンの充填箇所付近を高速回転エアータービン（３０万回転／分）により切削したが、切削の衝撃によりコンポジットレジンの剥離は生じなかった。つまり、実施例１の模型歯は、コンポジットレジンとの接着性が良好である。 The obtained enamel part and dentin part were joined using an adhesive (TB1773E, manufactured by ThreeBond Co., Ltd., photocuring imparted instantaneous adhesive by anionic polymerization) to obtain a model tooth. The enamel part and the dentin part were not easily peeled off, and the adhesiveness between the enamel part and the dentin part was good.
Further, a part of the model tooth obtained was cut to form a recess in the model tooth, and then the recess formed with an acrylic resin composite resin was filled and cured. After the composite resin was cured, the vicinity of the filled portion of the composite resin was cut with a high-speed rotating air turbine (300,000 rpm), but the composite resin was not peeled off due to the impact of the cutting. That is, the model tooth of Example 1 has good adhesiveness with the composite resin.
［実施例２～８及び比較例１］
　実施例２では、下記組成の尿素樹脂前駆体を用いてエナメル質部と象牙質部とを形成し、実施例１と同様にしてエナメル質部と象牙質部とを接合して模型歯を作製した。
　実施例３～８では、下記組成の尿素樹脂前駆体に対して、模型歯の材料中の充填材の含有量が表１に記載の量（質量％）になるように、表１に記載の種類の充填材を配合して得られた尿素樹脂前駆体を用いてエナメル質部と象牙質部とを形成し、実施例１と同様にしてエナメル質部と象牙質部とを接合して模型歯を作製した。
　比較例２では、ビスフェノールＡ型エポキシ樹脂と硬化剤とを含むエポキシ樹脂組成物を用いて、注型法によりエナメル質部と象牙質部とを形成し、実施例１と同様にしてエナメル質部と象牙質部とを接合して模型歯を作製した。
＜尿素樹脂前駆体＞
　ユリアホルムアルデヒド樹脂（リードライト（登録商標）ＷＴ－２０８６、株式会社台和製）：７０質量部
　ホルムアルデヒド：１質量部
　ヘキサメチレンテトラミン：１質量部 [Examples 2 to 8 and Comparative Example 1]
In Example 2, an enamel part and a dentin part are formed using a urea resin precursor having the following composition, and a model tooth is produced by joining the enamel part and the dentin part in the same manner as in Example 1. did.
In Examples 3 to 8, with respect to the urea resin precursor having the following composition, the content of the filler in the model tooth material is set to the amount (% by mass) described in Table 1, and is described in Table 1. An enamel part and a dentin part are formed using a urea resin precursor obtained by blending various kinds of fillers, and the enamel part and the dentin part are joined in the same manner as in Example 1. Teeth were made.
In Comparative Example 2, an enamel part and a dentin part were formed by a casting method using an epoxy resin composition containing a bisphenol A type epoxy resin and a curing agent, and the enamel part was formed in the same manner as in Example 1. And dentin part were joined to make a model tooth.
<Urea resin precursor>
Urea formaldehyde resin (Readlight (registered trademark) WT-2086, manufactured by Taiwa Co., Ltd.): 70 parts by mass Formaldehyde: 1 part by mass Hexamethylenetetramine: 1 part by mass
　得られた、実施例２～８及び比較例１の模型歯について、エナメル質部のビッカース硬度と、エナメル質部の切削感と、成形性とを評価した。これらの評価結果を、表１に記す。なお、切削感と成形性とは、下記方法に従って評価した。 The obtained model teeth of Examples 2 to 8 and Comparative Example 1 were evaluated for Vickers hardness of the enamel part, cutting feeling of the enamel part, and formability. These evaluation results are shown in Table 1. The cutting feeling and formability were evaluated according to the following methods.
＜切削感の評価＞
　歯科治療技術に習熟した１０名のパネラーによる切削試験を行い、試験片の切削感を以下の基準に従って評価した。切削感の評価には、ＰＡＮＡ－ＭＡＸ（ハンドピース、株式会社ナカニシ製）のタービンとダイヤモンドバーとを用いた。１０名のパネラーによる評価の回答のうち、もっとも回答数の多かった評価をその試験片の切削感の評価結果とした。
◎：天然の歯牙の切削感と同等
○：ほぼ天然の歯牙の切削感と同等
△：天然の歯牙の切削感との違いは感じられるが、天然の歯牙に近い切削感
×：天然の歯牙の切削感と大きく異なる <Evaluation of cutting feeling>
A cutting test was conducted by 10 panelists who were proficient in dental treatment technology, and the cutting feeling of the test piece was evaluated according to the following criteria. For the evaluation of cutting feeling, a turbine and diamond bar of PANA-MAX (handpiece, manufactured by Nakanishi Co., Ltd.) were used. Among the responses of the evaluation by the 10 panelists, the evaluation with the largest number of responses was taken as the evaluation result of the cutting feeling of the test piece.
◎: Equivalent to the cutting feeling of natural teeth ○: Almost equivalent to the cutting feeling of natural teeth △: Differences in cutting feeling from natural teeth are felt, but cutting feeling close to natural teeth ×: Natural teeth Very different from the cutting feeling
＜成形性評価＞
　射出成形時の成形性を、以下の基準に従って評価した。なお、比較例１の模型歯については、射出成型により製造されていないため、成形性を評価できない。成形性については、成形時の樹脂の流動性及び離形性と、製品の外観（艶の有無；バリ、ヒケ、フローマーク、反り、ジェッティング、ウェルドライン、焼け、及び気泡の発生の有無）とから総合的に判断し、◎、○、△及び×の４段階に格付けした。 <Formability evaluation>
The moldability at the time of injection molding was evaluated according to the following criteria. In addition, about the model tooth of the comparative example 1, since it is not manufactured by injection molding, a moldability cannot be evaluated. As for moldability, resin flowability and releasability during molding and appearance of the product (existence of gloss; presence of burrs, sink marks, flow marks, warpage, jetting, weld lines, burns, and bubbles) Based on the above, it was rated in four levels, ◎, ○, Δ, and ×.
　表１から分かるように、尿素樹脂を用いて製造された実施例２～８の模型歯は天然の歯牙と同等か近い切削感を有する。また、実施例３～８より、模型歯を構成する材料が充填材を含む場合、天然の歯牙の切削感により近い切削感を有する模型歯を得やすく、充填材がシリカである場合、切削感が特に良好である模型歯を得やすいことが分かる。
　他方、エポキシ樹脂からなる比較例１の模型歯は、切削感が天然の歯牙と大きくかけ離れたものであることが分かる。 As can be seen from Table 1, the model teeth of Examples 2 to 8 manufactured using urea resin have a cutting feeling equivalent to or close to natural teeth. Further, from Examples 3 to 8, when the material constituting the model tooth includes a filler, it is easy to obtain a model tooth having a cutting feeling closer to that of natural teeth, and when the filler is silica, the cutting feeling is obtained. It can be seen that it is easy to obtain model teeth that are particularly good.
On the other hand, it can be seen that the model tooth of Comparative Example 1 made of an epoxy resin has a feeling of cutting far from natural teeth.
　また、実施例２より、充填材を含まない尿素樹脂前駆体を用いて射出成形により模型歯を製造する場合、成形性が極めて良好であることが分かり、実施例３～８より、尿素樹脂前駆体が充填材を含む場合であっても、射出成形による成形性は著しく損なわれないことが分かる。 Further, Example 2 shows that when a model tooth is manufactured by injection molding using a urea resin precursor containing no filler, the moldability is extremely good. From Examples 3 to 8, the urea resin precursor is obtained. It can be seen that the moldability by injection molding is not significantly impaired even when the body contains a filler.
［実施例９～１５］
　実施例９～１５では、下記組成の尿素樹脂前駆体に対して、模型歯の材料中の充填材（Ｘ線造影性を有する充填材）の含有量が表２に記載の量（質量％）になるように、表２に記載の種類の充填材を配合して得られた尿素樹脂前駆体を用いてエナメル質部と象牙質部とを形成し、実施例１と同様にしてエナメル質部と象牙質部とを接合して模型歯を作製した。
＜尿素樹脂前駆体＞
　ユリアホルムアルデヒド樹脂（リードライト（登録商標）ＷＴ－２０８６、株式会社台和製）：７０質量部
　チタンホワイト：３質量部
　ホルムアルデヒド：１質量部
　ヘキサメチレンテトラミン：１質量部 [Examples 9 to 15]
In Examples 9 to 15, the content of the filler (filler having X-ray contrast properties) in the model tooth material is the amount (% by mass) shown in Table 2 with respect to the urea resin precursor having the following composition: The enamel part and the dentin part are formed using the urea resin precursor obtained by blending the fillers of the type shown in Table 2, and the enamel part is formed in the same manner as in Example 1. And dentin part were joined to make a model tooth.
<Urea resin precursor>
Urea formaldehyde resin (Readlight (registered trademark) WT-2086, manufactured by Taiwa Co., Ltd.): 70 parts by mass Titanium white: 3 parts by mass Formaldehyde: 1 part by mass Hexamethylenetetramine: 1 part by mass
　得られた、実施例９～１５の模型歯について、下記方法に従って、Ｘ線造影性と、色調と、成形性とを評価した。これらの評価結果を、表２に記す。
＜Ｘ線造影性＞
　模型歯を、ＪＩＳ　Ｔ６６０９－２の附属書Ｄ中の「Ｄ３．２　デジタルＸ線機器を用いる場合」に記載される方法に従ってＸ線撮影した。得られた像を観察し、以下の基準に従ってＸ線造影性を評価した。
◎：きわめて形状の明瞭な模型歯の像が確認される
○：形状の明瞭な模型歯の像が確認される
△：やや形状の不明瞭な模型歯の像が確認される
×：模型歯の像が確認されなかった The obtained model teeth of Examples 9 to 15 were evaluated for X-ray contrast, color tone, and moldability according to the following methods. These evaluation results are shown in Table 2.
<X-ray contrast>
The model teeth were X-rayed according to the method described in “D3.2 When using digital X-ray equipment” in Annex D of JIS T6609-2. The obtained image was observed and X-ray contrast property was evaluated according to the following criteria.
◎: An image of a model tooth with a very clear shape is confirmed. ○: An image of a model tooth with a clear shape is confirmed. △: An image of a model tooth with a slightly unclear shape is confirmed. The image was not confirmed
＜色調＞
得られた模型歯の色調を目視にて観察して、下記基準に従って模型歯の色調を評価した。
◎：色調が白色である
○：白色に近い色調であるが、Ｘ線造影性を有する充填材の色調に由来する着色がわずかに認められる
△：白色に近い色調であるが、Ｘ線造影性を有する充填材の色調に由来する着色が強く認められる
×：色調が白色と大きく異なる <Color tone>
The color tone of the obtained model tooth was observed visually, and the color tone of the model tooth was evaluated according to the following criteria.
A: The color tone is white. O: The color tone is close to white, but slight coloring derived from the color tone of the filler having X-ray contrast properties is observed. Δ: The color tone is close to white, but the X-ray contrast properties. The coloring derived from the color tone of the filler having a color is strongly recognized.
＜成形性評価＞
　射出成形時の成形性を、実施例２～８と同様の基準に従って、◎、○、△、及び×の４段階で評価した。 <Formability evaluation>
The moldability at the time of injection molding was evaluated according to the same criteria as in Examples 2 to 8, in four stages of ◎, ○, Δ, and ×.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　実施例９～１５より、模型歯を構成する材料がＸ線造影性を有する充填材としての作用を有する充填材を含む場合、模型歯にＸ線造影性が付与されることが分かる。実施例９～１２によれば、充填材が酸化ジルコニウムである場合、充填材を少量しか使用しなくてもＸ線造影性が良好な模型歯を得られることが分かる。充填材の含有量が少量である場合、白色の模型歯について色調の悪化が少なく、射出成形による成形性が良好である。 From Examples 9 to 15, it can be seen that when the material constituting the model tooth includes a filler having an action as a filler having X-ray contrast, X-ray contrast is imparted to the model tooth. According to Examples 9 to 12, it can be seen that when the filler is zirconium oxide, model teeth with good X-ray contrast can be obtained even if only a small amount of filler is used. When the content of the filler is small, there is little deterioration in the color tone of the white model teeth, and the moldability by injection molding is good.
　１０　模型歯
　１１　エナメル質部
　１２　象牙質部
　１３　歯髄部 10 model teeth 11 enamel part 12 dentin part 13 pulp part

Claims (10)

  1. 　象牙質部とエナメル質部とを備え、前記象牙質部及び前記エナメル質部の少なくとも一方が尿素樹脂を含む、歯科実習用模型歯。 Dental dental model tooth comprising a dentin part and an enamel part, wherein at least one of the dentin part and the enamel part contains urea resin.
  2. 　前記象牙質部と前記エナメル質部とが継ぎ目なく一体化されており、前記象牙質部と前記エナメル質部とが同一の材料からなる、請求項１に記載の歯科実習用模型歯。 The dental training model tooth according to claim 1, wherein the dentin part and the enamel part are seamlessly integrated, and the dentin part and the enamel part are made of the same material.
  3. 　前記象牙質部が前記エナメル質部に接合されている、請求項１に記載の歯科実習用模型歯。 The dental training model tooth according to claim 1, wherein the dentin part is joined to the enamel part.
  4. 　前記象牙質部と、前記エナメル質部とが、互いに異なる材質からなる、請求項３に記載の歯科実習用模型歯。 The dental training model tooth according to claim 3, wherein the dentin part and the enamel part are made of different materials.
  5. 　前記象牙質部及び前記エナメル質部の少なくとも一方が、尿素樹脂と充填材とを含む、請求項１～４のいずれか１項に記載の歯科実習用模型歯。 The dental practice model tooth according to any one of claims 1 to 4, wherein at least one of the dentin part and the enamel part contains a urea resin and a filler.
  6. 　前記充填材がＸ線造影性を有する充填材を含む、請求項５に記載の歯科実習用模型歯。 The dental training model tooth according to claim 5, wherein the filler includes a filler having X-ray contrast properties.
  7. 　前記象牙質部及び前記エナメル質部の少なくとも一方が、尿素樹脂と着色剤とを含む、請求項１～６のいずれか１項に記載の歯科実習用模型歯。 The dental practice model tooth according to any one of claims 1 to 6, wherein at least one of the dentin part and the enamel part contains a urea resin and a colorant.
  8. 　前記尿素樹脂又は前記尿素樹脂を含む組成物を用いる射出成形により、前記象牙質部と前記エナメル質部とを含み、前記象牙質部と前記エナメル質部とが継ぎ目なく一体化されている模型歯を形成する射出形成工程を含む、請求項２、５、６、又は７に記載の歯科実習用模型歯の製造方法。 A model tooth that includes the dentin part and the enamel part, and the dentin part and the enamel part are seamlessly integrated by injection molding using the urea resin or the composition containing the urea resin. The manufacturing method of the dental tooth for dental training of Claim 2, 5, 6, or 7 including the injection molding process which forms.
  9. 　前記尿素樹脂又は前記尿素樹脂を含む組成物を用いる射出成形により、前記象牙質部と、前記エナメル質部との少なくとも一方を形成する射出形成工程と、
    　前記象牙質部と、前記エナメル質部とを接合する接合工程と、を含む請求項３～７のいずれか１項に記載の歯科実習用模型歯の製造方法。     An injection molding step of forming at least one of the dentin part and the enamel part by injection molding using the urea resin or the composition containing the urea resin;
    The method for producing a dental tooth for dental training according to any one of claims 3 to 7, further comprising a joining step of joining the dentin part and the enamel part.
  10. 　前記尿素樹脂又は前記尿素樹脂を含む組成物を用いる多層射出成形により、前記象牙質部と、前記エナメル質部とを、同一の金型内で、両者が接合された状態で別個に形成する、請求項３～７のいずれか１項に記載の歯科実習用模型歯の製造方法。 By the multilayer injection molding using the urea resin or the composition containing the urea resin, the dentin part and the enamel part are separately formed in a state where both are joined in the same mold, The method for producing a dental tooth for dental training according to any one of claims 3 to 7.
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