JP2009053659A - Tooth for tooth model having enamel portion impregnated with resin or low melting point glass, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tooth model capable of exhibiting grinding feel similar to that of natural tooth, with which a student aspiring to become a dentist experiences intraoral work and practices treatment, and also experiences formation of an abutment tooth, formation of cavity, or the like. <P>SOLUTION: A difference in the grinding feel between tooth enamel and dentin which constitute a natural tooth is reproduced by impregnating a sintered body formed integrally of an inorganic powder, such as, alumina with a thermosetting resin or a low melting point glass so as to form an enamel portion. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a tooth used for a jaw model in which a student aiming at a dentist experiences intraoral work and practice treatment. A tooth for a jaw and tooth model is a tooth that is used for simulating a treatment action in the oral cavity or practicing treatment using a jaw and tooth model at a university or the like. The present invention particularly relates to a tooth used for cutting a tooth and experiencing form formation such as abutment tooth formation and cavity formation, and a manufacturing method thereof.

In the past, in the practice of dental treatment, extracted teeth from the human body and animals were used to experience the cutting feeling of natural teeth. However, the extracted tooth had a hygiene problem, and there was a possibility of infection without sufficient hygiene management, so it was not possible to practice freely. Moreover, since it is a natural living body, there is a problem of spoilage, and sufficient caution is required for storage.
Therefore, a method for experiencing the cutting feeling of a tooth without using a natural tooth has been demanded.

At present, teeth for a jaw and tooth model for practicing intraoral treatment are often made of epoxy resin and melamine resin, and are widely used.
However, although the tooth for jaw model made of epoxy resin and melamine resin has a natural tooth shape, it has a cutting feeling different from natural teeth, so practice of abutment tooth formation and cavity formation However, the cutting feeling and workability differed compared with the case of working in the actual oral cavity, and the practice effect was not obtained.

Specifically, natural teeth are composed of enamel and dentin, and enamel and dentin are harder than resins, and epoxy resins and melamine resins are softer and tend to cut more. Even after practicing treatment with model teeth, hard natural teeth tended not to be cut as expected.
Furthermore, the enamel and the dentin that cover the dentine-based crown are different in hardness. As a result, when cutting is transferred from enamel to dentin, the dentin may be strongly shaved and the shape may not be formed well.

  As a result of a demand for a harder material, a composite type is commercially available. Even if it is a composite type tooth, the dentin part and the enamel part have the same cutting feeling, so the cutting feeling is different from the natural tooth, so even if you practice abutment tooth formation and cavity formation, Compared with the case of working in the oral cavity, the cutting feeling and workability were different, and the practice effect was not obtained. The easy-to-understand expression has a feeling of slipping, and the cutting feeling is very different from natural teeth.

  In other words, it is required that the cutting feeling changes in the transition part from the enamel part to the dentin part of the tooth for the jaw and tooth model, as in the case of natural teeth. It is important to reproduce the cutting feel of dentin.

In Japanese Utility Model Laid-Open No. 1-90068, an enamel layer has a phlogopite crystal [NaMg ₃ (Si ₃ AlO ₁₀ ) F ₂ ] and a lithia / alumina / silica crystal (Li ₂ O · Al ₂ O ₃ · 2SiO ₂ , Li ₂ O · Al ₂ O ₃ · 4SiO ₂ ) is formed from glass / ceramics with Vickers hardness of 350 to 450 simultaneously precipitated, and white, red and yellow colorants are added to the polyol (main agent) in the root layer. In addition, an isocyanate prepolymer (curing agent) is further mixed and injected into the silicone rubber mold under vacuum, cured at room temperature and prepared in advance, and interposed between the enamel layer and the root layer. It is shown that the dentin recognition layer to which is attached is formed of an adhesive resin having an opaque color.

However, when the enamel layer is composed of phlogopite crystals or lithia / alumina / silica crystals, the cutting feeling is too hard compared to natural teeth, so it is not durable and the dentin recognition layer is adhesive. Because it was made of resin and the cutting feeling was too soft, it was not durable.
Furthermore, there is a description that a dentin layer is formed by an adhesive layer. It is shown that an enamel layer portion and a root layer portion are formed and bonded. It is recognized as a dentin layer with a thick adhesive layer.

Japanese Patent Application Laid-Open No. 5-224591 shows that a tooth model having cutting ability very similar to natural teeth and suitable for dental education cutting practice is provided.
As a constitution, at least the surface of the crown portion has a Knoop hardness of 70 or more, and at least the surface of the root portion has a Knoop hardness of 10 to 40. As main constituent components, inorganic powder and cross-linked resin are contained in a weight ratio of 20% to 80% to 70% to 30%.
In the text, there is a description that “it may be made of a material of any hardness, for example, metal, ceramics, resin, and may be a cavity from the viewpoint of the preparation method of the tooth model and economical viewpoint”. It was not a tooth model that showed the difference in machinability between the enamel part and the dentin part.

  Japanese Patent Laid-Open No. 5-216395 introduces the provision of a tooth model having a cutting ability very similar to that of natural teeth and suitable for dental education cutting practice and a method for manufacturing the same. Contains hydroxyapatite powder with a porosity of 40-80% and (meth) acrylic ester resin as a main component of the tooth model in a weight ratio of 20% to 80% to 50% to 50% It is what you are doing. However, it was not a tooth model that could show the difference in machinability between enamel and dentin.

  In JP-A-5-241498, JP-A-5-241499, and JP-A-5-241500, there are descriptions of inorganic fillers and hydroxyapatite fillers. It has not yet been resolved. However, it was not a tooth model that could show the difference in machinability between enamel and dentin.

Japanese Patent Application Laid-Open No. 2004-94049 describes an invention that provides a dental training model tooth that enables accurate shape measurement using a laser beam.
In the specification, “as the material constituting the crown surface of the model tooth of the present invention, generally known materials can be used, for example, ceramics or other porcelain or acrylic, polystyrene, polycarbonate, etc. , Acrylonitrile styrene butadiene copolymer (ABS), polypropylene, polyethylene, polyester, and other thermoplastic resin materials, melamine, urea, unsaturated polyester, phenol, epoxy, and other thermosetting resin materials, and their main raw materials Glass fiber, carbon fiber, pulp, synthetic resin fiber and other organic and inorganic reinforcing fibers, talc, silica, mica, calcium carbonate, barium sulfate, alumina and other fillers, pigments, dyes and other colorants, or What added various additives, such as a weathering agent and an antistatic agent, can be used. Is described with, but there is no description of the preferred material, it was not intended to resolve the grinding feel.

As a result of research, it was found that it was necessary to use a sintered body of an inorganic material in order to give a natural tooth cutting feeling, but it was difficult to control the hardness of the inorganic material. It was difficult to produce the enamel part and the dentin part while controlling the temperature.
In particular, when a tooth model is made of a fired body of the same inorganic material for the enamel part and the dentin part, it is difficult to reproduce the difference in cutting feeling between the enamel part and the dentin part.

In order to reproduce the difference in cutting feeling between the enamel portion and the dentin portion, it is conceivable to separately prepare the enamel portion and the dentin portion and adjust the cutting feeling of each portion.
In order to adjust the cutting feeling of the fired body, it is necessary to match the density, grain shape, and firing temperature of the fired body, but the shrinkage rate and thermal expansion coefficient of the enamel part and dentin part during firing are different. Cracking, peeling, cracking, etc., and a gap between the dentin part and enamel part may cause chipping at the time of cutting, and the gap conveys a feeling different from the cutting feeling of natural teeth and withstands use. It was not a thing.
In particular, when the enamel portion and the dentin portion are produced as separate fired bodies, it is necessary to bond the enamel portion and the dentin portion, and the cutting feeling varies greatly in the interface region including the bonded portion. That is, when a transition is made from the enamel part to the dentin part, a sense of incongruity is generated, resulting in a tooth model that is largely separated from the natural tooth.

In addition, when natural teeth are cut, a sticky cutting feeling unique to cutting a living body can be obtained.
A number of methods have been tried to express such a sticky cutting feeling unique to natural teeth, but with a resin, composite, etc., a sufficient cutting feeling cannot be obtained, and the conventional jaw tooth model There was no such a sensation even when irrigating teeth. Even in the case of enamel, there is a demand for a cutting sensation that feels more viscous than the cutting sensation of inorganic materials due to the same phenomenon.

That is, the conventional tooth model is not in a satisfactory condition in terms of machinability. Therefore, although it has been shown that development of a tooth model similar to natural teeth in cutting ability is desired, it does not show a sufficient cutting feeling. In particular, there has been a demand for a tooth having a stickiness peculiar to natural teeth, and it was not a tooth model that could show a difference in machinability between an enamel part and a dentin part.
However, there is currently no research report on the specific composition of the tooth model that achieves the cutting feeling of the enamel and dentin of natural teeth and the method for producing them.

  Therefore, the enamel part and the dentin part are made using the same inorganic material, and it expresses the sticky cutting feeling unique to natural teeth, and further reproduces the difference in cutting feeling between the enamel part and the dentin part. There is a need for a tooth model.

  So far, no method has been developed to reproduce the pulp that is unique to natural teeth, and dental students have never been able to experience open-bone experience. Bare pulp (shaving down to the part of the dental pulp) is the most important technique in dental treatment, and if it is accidentally exposed, it is necessary to learn the subsequent treatment method at the same time.

As caries of natural teeth progresses, the treatment method advances to the enamel layer, dentin layer, and dental pulp, and practice of root canal treatment such as extraction is also an important treatment. Even when performing pulpectomy, the dental pulp was removed with a reamer, and the feeling of rubbing the dentin wall surface with the reamer was completely different, so practice such as root canal filling was not possible.
Some dental pulp treatments are used for practicing root canal treatment, but the box-shaped acrylic has a small hole, and practicing root canal treatment (root canal cleaning, root canal dilation, etc.) Yes. However, due to the fact that it cannot be worn on the chin and the hardness of dentin, etc., there is a situation where sufficient practice has not been achieved.
There is a demand for a tooth for a jaw and tooth model that can easily perform these experiences. In particular, when cleaning the root canal, the pulp is completely removed up to the apical foramen, or it can be learned with the sense of the hand, which is difficult for beginners. Therefore, it is necessary to practice using a tooth for a jaw and tooth model in which the pulp of a natural tooth is reproduced.

  Further, caries removal is an important treatment in dental treatment, but the caries portion is much softer than a normal dentin portion, so that the caries portion is difficult to cut. Therefore, it is necessary to practice using jaw teeth model teeth in which caries in natural teeth are reproduced. Further, there has been a demand for a method for confirming that the caries portion has been accurately removed.

Japanese Utility Model Publication No. 1-90068 Japanese Patent Laid-Open No. 5-224591 JP-A-5-216395 JP-A-5-241498 JP-A-5-241499 JP-A-5-241500 JP 2004-94049 A

  An object of the present invention is to provide a tooth for a jaw and tooth model that can experience the same sensation as when treating natural teeth. In particular, the present invention provides a tooth for a jaw tooth model in which a difference in cutting feeling between enamel and dentin in a natural tooth is reproduced in a tooth for a jaw tooth model including an enamel part and a dentin part. is there.

  The present invention relates to a tooth for a jaw and tooth model for treatment practice including an enamel part and a dentin part, wherein the enamel part and the dentin part are formed of a sintered body of an inorganic powder, and the inorganic powder constituting the fired body There is provided a tooth for a jaw and tooth model in which voids exist between the particles, and the voids in the enamel portion are impregnated with resin or low-melting glass.

  In the tooth for a jaw and tooth model of the present invention, the enamel portion and the dentin portion can be integrally formed of a sintered body of inorganic powder. An enamel portion is formed by impregnating a part of the obtained fired body with resin or low-melting glass.

  In the tooth for a jaw and tooth model of the present invention, as the resin, a thermosetting resin such as urea resin, melamine resin, phenol resin, and epoxy resin or a thermoplastic resin containing a crosslinking agent can be used, and the low melting glass As, glass which flows at 200 ° C. to 600 ° C. can be used.

  Since the enamel portion and the dentin portion are integrally formed of a fired body having the same composition, an adhesive layer between the enamel portion and the dentin portion is eliminated. As a result, the transition from the enamel part to the dentin part is smooth during cutting.

  For the tooth for a jaw and tooth model of the present invention, for example, powders of inorganic materials such as alumina, zirconia, titanium oxide, and silica can be used, but the present invention is not limited thereto, and various inorganic powders are used. And mixtures thereof can be used.

  The jaw model tooth is a substitute for the hardest natural tooth in the human body, and ordinary materials feel soft during cutting, whereas the jaw model tooth according to the present invention is made of an inorganic material. Therefore, a cutting feeling similar to that of natural teeth can be obtained. A cutting experience similar to that using a diamond abrasive (using an air turbine) rotating at a high speed of 400,000 rotations / minute in the oral cavity can be performed.

In the present invention, it is preferable that an inorganic powder is injection-molded using a ceramic injection mold (CIM) technique to form an injection body having a desired shape, and the obtained injection body is fired.
Since the compatibility between the tooth and the jaw is important for contact with the cutting body that rotates at high speed, it is preferable to use a CIM technique that can be precisely molded in molding.
Furthermore, the shape of the crown of the tooth model is also important, and it is important that the ridges, fossa, and cusps are accurately expressed as the objective of abutment tooth formation and cavity formation. Is suitable.

  In the tooth for a jaw and tooth model of the present invention, the pulp portion can be formed inside the dentin portion. The dental pulp portion is filled with resin, silicone rubber, wax or water-soluble material.

  In the tooth for a jaw and tooth model of the present invention, a pseudo caries portion can be formed between the enamel portion and the dentin portion or at the edge thereof. The pseudo caries portion is formed of a fired body of resin or inorganic powder.

The tooth for a jaw and tooth model of the present invention is a fired body integrally molded using an inorganic material, and includes an enamel portion and a dentin portion. Since it is integrally molded, there is no adhesive layer between the enamel part and the dentin part, and the transition during cutting can be made smoothly without feeling the soft feeling of the adhesive.
Since the enamel portion is formed by impregnating a thermosetting resin, a thermoplastic resin containing a cross-linking agent, or a low-melting glass, a hard cutting feeling close to that of the enamel layer can be obtained as compared with a case where the enamel portion is not impregnated.
Both dentin part and enamel part have the same cutting feeling as natural teeth, and the cutting feeling of transition from enamel part to dentin part is close to natural teeth, so it is easy to practice cutting natural teeth even with a model. Yes.

  By using the tooth for a jaw and tooth model of the present invention to form an abutment tooth and a cavity, a cutting feeling similar to that of a natural tooth can be experienced as soon as possible, and the formation experience can be easily performed. Moreover, these formation techniques can be acquired quickly.

  Furthermore, the tooth of the present invention can be experienced as a root canal treatment or a caries treatment technique by forming a dental pulp portion or a pseudo caries portion.

The tooth 1 for a jaw and tooth model of the present invention includes at least an enamel portion 11 and a dentin portion 12 as shown in FIG.
As shown in FIG. 2, the enamel portion 11 and the dentin portion 12 are integrally formed of a fired body of inorganic powder, and a desired region of the fired body is impregnated with a resin or low-melting glass, thereby enamel portion 11. Form.

The inorganic powder fired body 2 constituting the tooth 1 for a jaw and tooth model of the present invention is constituted by sintering of inorganic powder particles 21 as shown in FIG. Further, voids 22 exist between the particles 21.
This void 22 is impregnated with resin or low-melting glass 3 to form an enamel portion 11 that is harder than the dentin portion 12 and has a sticky cutting feel similar to that of natural teeth.

Next, as shown in FIG. 4, inorganic powder is injection molded to form an injection body of a desired shape, and the fired body obtained by firing the obtained injection body (FIG. 4A) is made of resin or By immersing in a container filled with the low-melting glass 3 (FIG. 4B), the resin or the low-melting glass 3 is impregnated in a desired portion to be the enamel portion 11 (FIG. 4C).
It is preferable to impregnate the fired body with resin or low melting point glass 3 in a vacuum vessel. Impregnation can be facilitated by eliminating the air inside the gap 22 of the fired body 2 under reduced pressure.

In the tooth 1 for jaw model of the present invention, the pulp portion 13 can be formed inside the dentin portion 12 (FIG. 5).
In order to form the pulp portion 13 inside the dentin portion 12, a mold having a desired pulp shape is formed using a combustible material such as an epoxy resin. The pulp-shaped mold is placed in a mold, and an injection body is formed from inorganic powder. By firing this, the dental pulp-shaped mold is burned down, and a tooth 1 having a pulp-shaped space inside is obtained. . The dental pulp portion 13 is formed by filling the obtained pulp-shaped space with resin, silicone rubber, wax or water-soluble material.

In the tooth for a jaw and tooth model of the present invention, a pseudo carious portion 14 can be formed between the enamel portion 11 and the dentin portion 12 or at the edge thereof. FIG. 6 shows a schematic view in which a pseudo caries 14 is formed at a transition portion between the enamel portion 11 and the dentin portion 12 of the jaw model tooth.
Further, as shown in FIG. 7, the pseudo carious portion 14 can be formed so as to penetrate from the occlusal surface of the enamel portion to the dentin portion, and the pseudo carious portion 14 can be formed together with the dental pulp portion 13.
The pseudo caries portion 14 is formed of a sintered body of inorganic powder, resin or composite. When the pseudo caries portion 14 is formed of a resin or a composite, a coloring agent, a fluorescent material or an X-ray contrast material is added to the sintered body of the inorganic powder, the resin or the composite so that the degree of caries portion removal can be visually confirmed. can do.

  The tooth for the jaw tooth model of the present invention can be made white, ivory, milky white, translucent color by using inorganic pigments like natural teeth, so that it has a more realistic cutting experience Can do. Preferred are white, ivory and milky white.

  In the tooth for a jaw and tooth model of the present invention, the jaw field and the mannequin portion can be appropriately selected. However, it is important to take measures to confirm the suitability for selection. For example, it is important to appropriately match the size of the tooth insertion opening of the jaw model.

Examples of the inorganic powder that can be used to form the tooth for the jaw model of the present invention include ceramics or glass such as alumina, zirconia, silica, aluminum nitride, and silicon nitride. Alumina and zirconia are preferred.
Alumina-based and zirconia-based are that alumina or zirconia is 60% to 100%, preferably 80% to 100%, more preferably 95% to 100% of the fired body composition. In particular, the composition of alumina is 50% to 100%, preferably 70% to 100%, and more preferably 90% to 100%.
It is preferable to use alumina-based ceramics as the inorganic powder.

  When teeth are formed from a sintered body of inorganic powder, the hardness can be adjusted by coarsening the particle size, increasing the voids, changing the composition, changing the firing temperature, changing the mooring time, etc. is there.

The average particle size of the sintered inorganic powder can be 0.1 to 10 μm and is preferably set to 1.0 to 5.0 μm.
Although the firing temperature varies depending on the composition, the firing temperature is 800 to 1200 ° C. when there are many glass components such as silica, and the firing temperature is 1200 to 1600 ° C., preferably 1400 to 1550 ° C. in the case of alumina.

The tooth for a jaw and tooth model of the present invention is preferably formed of a sintered body of alumina powder. In this case, the primary particle diameter of the alumina powder is preferably 0.2 to 5 μm, and is preferably fired at a firing temperature of 1300 to 1600 ° C.
The firing temperature is closely related to the cutting feeling and must be adjusted according to the particle size and raw materials. Similarly, the mooring time at the firing temperature is closely related to the cutting feeling and must be adjusted according to the particle size and raw materials.
The Vickers hardness of the fired body constituting the tooth for a jaw and tooth model of the present invention is preferably 300 to 1000, and more preferably 300 to 600.
In addition, it does not prevent adding a metal oxide typified by silica to the tooth composition to such an extent that the cutting feeling of the alumina fired body is not impaired.

It is preferable to use the CIM technique often used as a ceramic forming method for forming an injection body for obtaining a fired body of a tooth for a jaw and tooth model of the present invention.
The CIM technology is a technology for molding inorganic powder and includes the following steps.
(1) Alumina is kneaded with a binder (which decomposes by heat up to about 1000 ° C.) to produce pellets.
(2) A mold for injection molding having a fixed shape is produced, and the pellet produced in (1) is injection molded.
(3) After molding, the binder is degreased (the temperature is raised to decompose the binder component).
(4) Next, the degreased body is fired at a predetermined temperature to obtain a desired fired body.

  Examples of the binder that can be used in the present invention include stearic acid, polyvinyl alcohol, a thermoplastic resin, and wax, and it is preferable to use stearic acid or polyvinyl alcohol.

The thermoplastic resin refers to a resin that can obtain a thermoplasticity that can be molded by applying heat.
The thermoplastic resin used in the present invention specifically includes acrylic, styrene, olefin, vinyl chloride, urethane, polyamide, polybutadiene, polyacetal, unsaturated polyester, polycarbonate, polyphenylene ether, and the like. .
Polysulfone, polyimide, polyetherimide, polyetheretherketone and the like can also be used as appropriate. In particular, an acrylic type is preferable.

  As the wax, both natural wax and synthetic wax can be used. Examples of natural waxes include animal and plant waxes, mineral waxes, and petroleum waxes. Compound wax, polyethylene wax, etc. can be used as the synthetic wax. Paraffin wax is preferred. The wax system also includes fats and oils. Oils and fats are glycerin esters of fatty acids. Not soluble in water but soluble in alcohol. It is preferably a fat that is solid at room temperature (37 ° C., atmospheric pressure). There are vegetable waxes, animal beef tallow and pork tallow. Specifically, lauric acid, myristic acid, palmitic acid, behenic acid, stearic acid, fats and oils extracted from the living body, and the like can be used, and fats and oils extracted from the living body are preferable. Particularly, fats derived from pigs and cows are preferable (representative examples include lard and head).

  The tooth form is injection-molded using CIM technology, the teeth of the calcined product obtained through the degreasing and firing processes are immersed in resin or molten low-melting glass, and the desired part is impregnated with resin or glass to enamel Forming part. Under reduced pressure, it is preferable to impregnate the teeth of the fired body with resin or molten glass and return to normal pressure.

  As the resin to be impregnated for use in the present invention, a thermosetting resin or a thermoplastic resin can be used.

A thermosetting resin is preferred to a thermoplastic resin. A thermosetting resin refers to a resin that does not dissolve in a solvent after processing and does not soften even when reheated. A urea resin, a melamine resin, a phenol resin, an epoxy resin, and the like can be typically used, and a melamine resin and an epoxy resin are preferable. Most preferred is an epoxy resin.
It is preferably a chemically polymerizable resin. This is because the resin is impregnated into the voids of the fired body and can be easily cured.

  The chemically polymerizable resin is a resin that is polymerized using a chemical catalyst even if it is originally contained in a thermosetting resin or a thermoplastic resin. Particularly preferred are those containing a cross-linking material and having no thermoplasticity.

The thermoplastic resin refers to a resin that can obtain thermoplasticity that can be molded by applying heat.
The thermoplastic resins that can be used to form the enamel portion of the present invention are specifically acrylic, styrene, olefin, vinyl chloride, urethane, polyamide, polybutadiene, polyacetal, and saturated polyester. , Polycarbonate, polyphenylene ether and the like. In particular, acrylic, styrene, urethane, and polyamide resins are preferable.
By mixing a crosslinking agent with these thermoplastic resins, it becomes a preferable embodiment like a thermosetting resin. That is, tooth cutting can be practiced without melting by the heat generated during cutting.

  The glass that can be used to form the enamel portion of the present invention is not particularly limited, but is preferably a low-melting glass that flows in the range of 200 to 600 ° C. If the temperature at which the glass starts to flow is 600 ° C. or less, it is preferable because the fired body made of inorganic powder is not deformed.

Such low melting point glass is preferably alumina silicate glass. The composition of the preferred glass, _Al 2 _{O 3} is 5 to 40% SiO ₂ is 20 to 90%, and more preferably _Al 2 _{O 3} is 20 to 35% SiO ₂ is 35 to 70% further _Al 2 _{O 3} is 25 to 33%, it is preferably SiO ₂ is 50 to 65%.

In order to lower the melting point, it is preferable to contain 1 to 15%, more preferably 3 to 10% of one or more of sodium oxide, potassium oxide, lithium oxide and lanthanoid oxides. In particular, it is preferable to add ₂ to 10% of LaO2.

  As other compounding components, it is preferable to add boric acid, phosphoric acid, sodium oxide, potassium oxide, lithium oxide, lime, magnesium, strontium oxide, barium oxide, lead oxide, titania, zinc oxide, zirconia as appropriate.

  As auxiliary materials, petal, cobalt trioxide, nickel oxide, potassium dichromate, chromium oxide, manganese dioxide, potassium permanganate, vanadium pentoxide, metal selenium, sodium selenite, cupric oxide, copper sulfate, It is preferable to add cuprous oxide, gold chloride, silver nitrate, sulfur white, sodium sulfide, fluorite, sodium silicofluoride, and apatite.

  By adding a compounding component having a coloring action to glass, it is possible to easily color only the enamel portion in order to increase the visibility of the enamel portion.

  In order to reproduce the same sticky cutting feeling as natural teeth in the dentin part of the tooth for a jaw and tooth model of the present invention, after forming the enamel part, water-soluble It can be impregnated with materials, heat-soluble materials or organic materials.

As the water-soluble material, any water-soluble polymer that can be impregnated in the voids of the fired body can be used without particular attention. It is preferable that it is at least one of polysaccharides and proteins. A protein is preferred.
When impregnated with a water-soluble material, the effect is exhibited by pre-impregnating with water or water.

  As the polysaccharide, dextrin, glycogen, cellulose, pectin, konjac mannan, glucomannan and alginic acid are preferable. Preferred are cellulose, pectin, konjac mannan and glucomannan. This is because a certain degree of viscosity is necessary.

  The protein may be a high molecular compound mainly composed of a polypeptide comprising about 20 kinds of L-α-amino acids. From the viewpoint of composition, it is preferable to use a simple protein consisting only of amino acids and a complex protein containing nucleic acid, phosphate, lipid, sugar, metal and the like. More preferred are gelatin, agar, collagen and elastin. Still more preferred are gelatin and agar. This is because it is necessary not to dissolve more and more in water but to maintain the shape in the voids of the fired body.

A wax system can be used as the heat-soluble material.
When impregnated with a heat-soluble material, the effect is exhibited by melting with frictional heat generated during cutting. Even if water is not used as a wax system, it exhibits the same effect as polysaccharides and proteins, and tooth grinding practice can be easily performed even without water injection equipment.

  As the wax-based composition, both natural wax and synthetic wax can be used. Examples of natural waxes include animal and plant waxes, mineral waxes, and petroleum waxes. Compound wax, polyethylene wax, etc. can be used as the synthetic wax. Paraffin wax is preferred. The wax system also includes fats and oils. Oils and fats are glycerin esters of fatty acids. Not soluble in water but soluble in alcohol. It is preferably a fat that is solid at room temperature (37 ° C., atmospheric pressure). There are vegetable waxes, animal beef tallow and pork tallow. Specifically, lauric acid, myristic acid, palmitic acid, behenic acid, stearic acid, fats and oils extracted from the living body, and the like can be used, and fats and oils extracted from the living body are preferable. Particularly, fats derived from pigs and cows are preferable (representative examples include lard and head).

Impregnation can be assisted by mixing the surfactant during the impregnation. That is, the surfactant auxiliary agent plays an important role in impregnating the voids of the fired body with these water-soluble materials or heat-soluble materials.
Surfactants can also be used as water-soluble materials.

As the surfactant, an anionic, nonionic, cationic, zwitterionic or the like can be used as appropriate. Anionic and nonionic are preferable.
Examples of anionic compounds include fatty acid salts (soap) C ₁₁ H ₂₃ COONa, alpha sulfo fatty acid ester salts (α-SFE) C ₁₀ H ₂₁ —CH (SO ₃₃ Na) COOCH ₃ , alkylbenzene sulfonates (ABS) C ₁₂ H _25- (C ₆ H ₄ ) SO ₃ Na, alkyl sulfate (AS) [higher alcohol type] C ₁₂ H ₂₅ -OSO ₃ Na, alkyl ether sulfate (AES) C ₁₂ H ₂₅ -O (CH ₂ CH ₂ O) ₃ SO ₃ Na, alkylsulfuric triethanolamine C ₁₂ H ₂₅ —OSO ₃ ^— · ⁺ NH (CH ₂ CH ₂ OH) _{3 and the} like are used.
Nonionics include fatty acid diethanolamide C ₁₁ H ₂₃ -CON (CH ₂ CH ₂ OH) ₂ , polyoxyethylene alkyl ether (AE) C ₁₂ H ₂₅ -O (CH ₂ CH ₂ O) ₈ H, polyoxy polyoxyethylene alkyl phenyl ether _{(APE) C 9 H 19 -} (C 6 H 4) O (CH 2 CH 2 O) 8 H , or the like is used.
Alkyltrimethylammonium salts as cationic ^{_{C 12 H 25 -N + (CH}} 3) 3 · Cl -, dialkyl dimethyl ammonium chloride ^{_{C 12 H 25 -N + (C}} 8 H 17) (CH 3) 2 · Cl - alkyl pyridinium chloride ^{_{C 12 H 25 - (N +}} C 5 H 5) · Cl - or the like is used.
As the zwitterionic system, alkylcarboxybetaine [betaine system] C ₁₂ H ₂₅ -N ⁺ (CH ₃ ) ₂ .CH ₂ COO ^- or the like is used.

A method for impregnating a water-soluble material or a heat-soluble material will be described below.
The water-soluble material or heat-soluble material to be impregnated is put into a beaker and heated to an appropriate temperature to lower the viscosity. Add moderate surfactant. When the viscosity drops, the ceramic fired body is charged and placed in a vacuum desiccator. As the air in the vacuum desiccator is evacuated and the air in the ceramic fired body is released to the outside, as the pressure is reduced, bubbles appear on the surface of the fired body, and the air inside has been removed. Look at the situation and when the air comes out, impregnate it by gently returning the air to the desiccator.

  The organic material is preferably at least one of a thermosetting resin, a thermoplastic resin, and a resin containing a crosslinking agent. Furthermore, an epoxy resin is preferable.

A method for forming pseudo dental caries and pseudo pulp in the tooth for jaw model of the present invention will be described below.
CIM so as to cover the carious part and pulp part made with this combustible thermosetting resin material when the caries part and pulp part are made with the combustible thermosetting resin material and the tooth is made with the mold. The material is injection-molded, and then the caries and pulp portions are made hollow by firing.
Resin or silicone rubber is poured into the hollow caries or dental pulp to produce pseudo caries or pseudo pulp.
Caries are created in the fossa of the occlusal surface and the enamel dentin transition. In the case of making a foveal portion or the like, the enamel is not greatly affected, but the dentin portion is often greatly affected. A method for reproducing such a bag-like caries site has not been established.
Similarly, in the pulp shape, only a small hole like the apical hole is open to the outside, and a method for reproducing a bag-shaped pulp portion having a large pulp portion inside has not been established.

When the enamel portion of the tooth is impregnated with the resin, the carious portion or the pulp portion may be impregnated with the resin at the same time. Before impregnating the enamel part of the tooth with resin, the carious part or pulp part is impregnated with resin, and the resin is impregnated into the carious side inorganic powder fired body or the pulp side inorganic powder fired body by polymerizing and curing in advance. It is preferable that the cutting feeling is closer to that of natural teeth.
The material used for the carious portion and the dental pulp portion can be freely selected from an elastic resin, a foamed resin, a thermosetting resin, a thermoplastic resin, a resin containing a crosslinking agent, a water-soluble material, a heat-soluble material, and the like.
Preferred resins used for the caries portion are foamed resin and thermosetting resin. More preferably, a thermosetting resin or a resin containing a crosslinking agent is preferable. Furthermore, an epoxy resin is preferable.
Preferred resins used for the dental pulp are elastic resin, foamed resin, and thermosetting resin.

  The water-soluble material and heat-soluble material that can be used for the carious portion and the dental pulp portion and the impregnation method are the same as described above.

  The silicone rubber of the carious part and the pulp part in the ceramic fired body of the tooth for a jaw and tooth model of the present invention can be used without any limitation. Application to the pulp portion is particularly preferable. Other rubber materials that can be used include: chlorosulfonated polyethylene rubber: hyperon rubber, fluorine rubber, isobutene isoprene rubber: butyl rubber, natural rubber, acrylonitrile butadiene rubber: hiker, urethane rubber, ethylene propylene rubber, styrene butadiene rubber, chloroprene rubber: Neoprene is exemplified. Rubber height (durometer (JIS K 6253)) is 10 to 70, preferably 20 to 50.

The wax of the carious part and the pulp part in the ceramic sintered body of the tooth for a jaw and tooth model of the present invention is an animal-derived wax (beeswax, whale wax, shellac wax, etc.), a plant-derived wax (carnauba wax, wood wax, rice bran). Wax (rice wax), candelilla wax, petroleum-derived wax (paraffin wax, microcrystalline wax), mineral-derived wax (montan wax, ozokerite), synthetic wax (Fischer-Tropsch wax, polyethylene wax, oil-based synthetic wax ( Esters, ketones, amides), hydrogenated waxes, and the like can be used. Application to the pulp portion is particularly preferable. A wax derived from petroleum is preferable, and paraffin wax is particularly preferable.
The water-soluble material of the carious part and the pulp part in the ceramic fired body of the tooth for a jaw and tooth model of the present invention contains at least one of polysaccharide and protein. The water-soluble material can exert its effect by pre-impregnation with water injection or water. A protein is preferred.
A hydrophilic polymer is also preferred as the water-soluble material. For example, synthesis of polyvinyl alcohol (PVA), polyacrylic acid polymer, polyacrylamide (PAM), polyethylene oxide (PEO), etc. from cellulose derivatives such as semi-synthetic carboxymethylcellulose (CMC) and methylcellulose (MC) derived from nature Water-soluble polymers of the system can be used.

  The combustible material may be any material that can be shaped into a pulp shape and can be burned when the tooth is baked to create a pulp space without being deformed by the injection pressure and temperature when the tooth is formed. Specifically, it is a resin, and particularly preferably a thermosetting resin. Specifically, a urea resin, a melamine resin, a phenol resin, an epoxy resin, an acrylic resin, or a styrene resin may be used after being crosslinked.

The burnable pulp preparation process, which uses the combustible material to mold the combustible material pulp formed into the carious part and the pulp part, is a pre-burning material that is burned when the tooth is fired to form the dental pulp shape. This is a process of forming a carious portion and a dental pulp portion.
Since a tooth made of an inorganic material undergoes a firing process, a space is made with a combustion material at the time of firing, and then the tooth is completed by filling with a material suitable for the dental pulp. This is the pulp shape preparation process.
Mold installation process to install carious parts and pulp parts made of flammable material at a predetermined position in tooth mold is a process to install caries parts and dental pulp parts made of flammable materials in mold It is. Caries and dental pulp made of pre-molded combustible material may be placed in the mold, or caries and pulp made of combustible material continuously molded in situ Either part may be re-inserted into the tooth-shaped mold.

The injection process of injecting pellets made of inorganic powder and binder into a tooth mold to obtain an injection tooth is an inorganic tooth composition that is heated and mixed in a dental mold with a carious part and pulp part made of a combustible material. This is a step of injecting pellets made of powder and binder. In this process, the caries and dental pulp made of flammable material are thin and must be injected with care.
The firing step of obtaining a fired tooth by degreasing and firing the injection tooth is a step of firing the injection tooth obtained in the injection process. The firing temperature in the firing step is 800 to 1200 ° C. when the glass content is large, and 1200 to 1600 ° C., preferably 1400 to 1550 ° C. in the case of alumina. At this time, the carious portion and the dental pulp portion made of the combustible material are burned to form a space portion.

  The pulp preparation process that fills the burned carious part and dental pulp part with resin, silicone rubber, wax, water-soluble material, etc. means that the burned pulp space part is filled with resin, silicone rubber, wax, water-soluble material. And providing a pseudo pulp. There are a method of filling with a syringe or the like, and a method of filling the pulp portion of the fired body by dipping in a pseudo pulp material, placing it in a vacuum container and applying a vacuum.

  Next, the method for producing a tooth for a jaw and tooth model of the present invention will be described below.

(Manufacture of fired teeth)
Firing body 1:
A mold capable of injection molding the shape of the tooth form was produced. Using 1 kg of alumina pellets for CIM (100% Al ₂ O ₃ , average particle size 5.0 μm, stearic acid 30%) as a raw material for teeth, injection molding was performed on a tooth-shaped mold to obtain an injection body 1 .
The produced injection body in the form of a tooth was degreased and fired (1500 ° C., mooring time 10 minutes) to obtain a fired body 1.

Firing body 2:
A mold capable of injection molding the shape of the tooth form was produced. Using 1 kg of alumina pellets for CIM (100% Al ₂ O ₃ , average particle size 1.0 μm, stearic acid 30%) as a raw material of teeth, injection molding is performed on a mold of a tooth shape to obtain an injection body 2 It was.
The produced injection body in the form of a tooth was degreased and fired (1500 ° C., mooring time 10 minutes) to obtain a fired body 2.

(Resin impregnation)
The crown portions of the fired bodies 1 and 2 obtained were immersed in the following materials, put in a vacuum container, and decompressed. After leaving for 10 minutes, each material was impregnated by returning to normal pressure to form an enamel portion (Examples 1 to 6). The impregnation depth was 0.5 to 5.0 mm, although it varied depending on the particle size of the alumina powder contained in the alumina pellets and the impregnated resin material.
30 teeth were prepared for each, and the cutting feeling of the teeth was confirmed.

(Resin tested)
Epoxy resin (low viscosity epoxy resin Z-2 / H-07): An epoxy resin to which a catalyst was added was used. After returning to normal pressure, the sample was left for 72 hours, and then the cutting feeling was confirmed with a diamond bar.
Acrylic resin (manufactured by Kuraray, MMA monomer): An acrylic resin to which a chemical polymerization catalyst was added was used. After returning to normal pressure, the sample was left for 72 hours, and then the cutting feeling was confirmed with a diamond bar.
Melamine resin (RTV silicone resin M8017: Asahi Kasei): A silicone resin to which a catalyst was added was used. After returning to normal pressure, the sample was left for 72 hours, and then the cutting feeling was confirmed with a diamond bar.

  As comparative examples, fired bodies 1 and 2 that were not impregnated with anything were used (Comparative Examples 1 and 2).

Evaluation criteria (cutting feeling)
A: The cutting feeling of the dentin part and the enamel part was fully expressed.
B: The cutting feeling of the dentin portion and the enamel portion could not be expressed sufficiently.
(Dentin-enamel migration)
A: The difference in cutting feeling was sufficiently expressed during the transition between the dentin portion and the enamel portion.
B: At the time of transition between the dentin portion and the enamel portion, the difference in cutting feeling could not be expressed sufficiently.
C: At the time of transition between the dentin portion and the enamel portion, the difference in cutting feeling could not be expressed at all.

In Examples 1 to 6, the stickiness was felt as compared with Comparative Examples 1 and 2, and a cutting feeling similar to that of natural teeth was obtained. There was almost no crushing feeling peculiar to ceramics at the time of cutting, and it was close to the sense of cutting living teeth.
By controlling the amount of reduced pressure, the reduced pressure time, and the immersion time to adjust the impregnation depth of the resin, it was possible to create a tooth having an enamel portion and a dentin portion having different cutting feelings as with natural teeth.
When dentin and enamel were prepared separately, chipping between dentin and enamel was difficult, so it was not easy to practice tooth cutting.

(Glass impregnation)
A swamp made of the following materials was built up in the crown portions of the obtained fired bodies 1 and 2, and each material was impregnated by firing at the following temperature to form an enamel portion (Examples 7 to 7). 10). The impregnation depth was 0.5 to 5.0 mm, although it varied depending on the particle size of the alumina powder contained in the alumina pellets and the impregnated glass material.
30 teeth were prepared for each, and the cutting feeling of the teeth was confirmed.

(Glass tested)
PbO—SiO ₂ —B ₂ O ₃ : Firing temperature 550 ° C.
Alumina silicate glass: firing temperature 950 ° C

Evaluation criteria (cutting feeling)
A: The cutting feeling of the dentin part and the enamel part was fully expressed.
B: The cutting feeling of the dentin portion and the enamel portion could not be expressed sufficiently.
(Dentin-enamel migration)
A: The difference in cutting feeling was sufficiently expressed during the transition between the dentin portion and the enamel portion.
B: At the time of transition between the dentin portion and the enamel portion, the difference in cutting feeling could not be expressed sufficiently.
C: At the time of transition between the dentin portion and the enamel portion, the difference in cutting feeling could not be expressed at all.

In Examples 7 to 8, tenacity was felt and a cutting feeling similar to that of natural teeth was obtained. There was almost no crushing feeling peculiar to ceramics at the time of cutting, and it was close to the sense of cutting living teeth.
Create a tooth with enamel and dentin parts with different cutting feelings by adjusting the impregnation depth of low melting point glass by controlling the type of glass and firing time after glass building. I was able to.

  It can be used as a practice tooth for cutting natural teeth at a university that nurtures dentists.

Sectional drawing of the tooth for jaw model of this invention. Sectional drawing of the tooth for tooth models before forming an enamel part. The enlarged view of an inorganic powder sintered body. Schematic which shows the preparation methods of the tooth for jaw model of this invention. Sectional drawing of the tooth for jaw model of this invention containing a dental pulp part. Sectional drawing of the tooth for jaw tooth models of this invention containing a pseudo carious part. Sectional drawing of the tooth for jaw model of this invention containing a dental pulp part and a pseudo carious part.

Explanation of symbols

1 ... Tooth-shaped fired body,
11 ... Enamel part impregnated with resin,
12: Dentin portion not impregnated with resin,
13 ... dental pulp,
14 ... pseudo caries part,
2 ... sintered body of inorganic powder,
21 ... Particles of inorganic powder,
22: gap,
3: Resin or molten glass.

Claims (10)

  A tooth for a jaw and tooth model for treatment practice including an enamel part and a dentin part, wherein the enamel part and the dentin part are formed of an inorganic powder fired body, and between the inorganic powder particles constituting the fired body A tooth for a jaw and tooth model in which a void exists and the void in the enamel portion is impregnated with resin or low-melting glass.   The tooth for a jaw and tooth model according to claim 1, wherein the enamel portion and the dentin portion are integrally formed of a sintered body of inorganic powder.   The tooth for a jaw and tooth model according to claim 1 or 2, wherein the inorganic powder is selected from ceramic powders of alumina, zirconia, silica, titanium oxide, aluminum nitride, or silicon nitride.   The tooth for a jaw and tooth model according to any one of claims 1 to 3, wherein the resin is a thermosetting resin.   The tooth for a jaw and tooth model according to any one of claims 1 to 3, wherein the low melting point glass is a glass that flows in a temperature range of 200 ° C to 600 ° C.   The tooth for a jaw and tooth model according to claim 1, wherein a pulp portion is formed inside the dentin portion.   The tooth for a jaw and tooth model according to claim 6, wherein the dental pulp portion includes a resin, silicone rubber, wax, or a water-soluble material.   The tooth for a jaw and tooth model according to claim 1, further comprising a pseudo-carious portion on the dentin side between the enamel portion and the dentin portion or on the edge thereof or on the dentin side around the transition portion between the enamel portion and the dentin portion. A method of manufacturing a tooth for a jaw and tooth model for treatment practice including an enamel part and a dentin part,
A step of kneading the powder of the inorganic fired body with a binder to produce pellets,
A step of injection-molding the pellets using a mold for injection molding of a certain shape to form an injection body of a desired shape;
Heat treating the projectile to degrease the binder,
Firing a degreased injection body at a predetermined temperature to form a fired body having a desired shape, and impregnating a part of the fired body with resin or low-melting glass to form an enamel portion. A method for producing a tooth for a jaw and tooth model.   In the step of injection molding the injection body, a combustible pulp mold formed into a pulp shape using a combustible material is installed inside the injection body, and in the step of firing the injection body, the combustible pulp mold The method further comprises the step of: forming a pulp-shaped space in the dentin portion of the fired body by burning out, and further injecting resin, silicone rubber, wax or a water-soluble material into the pulp-shaped space. The manufacturing method of the tooth for jaw jaw models as described.

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