JP2007310372A - Method of producing tooth for gnathic tooth model, and application of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tooth for a gnathic tooth model both the dentin part and enamel part of which have cutting feel similar to that of a natural tooth and the cutting feel at the portion where the enamel part changes to the dentin part is close to that of a natural tooth, thus, which enables dental students to easily conduct practice of scaling a natural tooth. <P>SOLUTION: The tooth for a gnathic tooth model for practicing treatments comprises a dentin part and an enamel part. After the dentin part and the enamel part are produced, the dentin part and the enamel part are bonded together. The bonding agent is an organic resin composition, and the dentin part and the enamel part are composed of a baked inorganic powder. Preferably, the thickness of the bonding agent is 1-500 μm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention is a tooth used for a jaw and tooth model in which a student who aims to become a dentist experiences an intraoral work and practice treatment. More specifically, the present invention relates to a method for manufacturing a tooth used for experiencing formation of an abutment, formation of a cavity, and the like.

Teeth for a jaw and tooth model for intraoral treatment practice are often made of epoxy resin and melamine resin, and are widely used.
However, since epoxy resin and melamine resin have different cutting feelings, even when practicing abutment tooth formation and cavity formation, it is often embarrassed by the different cutting feeling and workability when working in the actual oral cavity. It was. Specifically, epoxy resins and melamine resins tend to be soft and increase cutting, and natural teeth tend to be hard to cut as expected because they are hard. Even in hard natural teeth, the dentin part is hard, but the enamel part is harder. As a result, there is a possibility that it will be sharply cut and the shape cannot be made well.

  As a result of a demand for a harder material, a composite type is commercially available. Even in composite type teeth, the dentin part and enamel part have the same cutting feeling, so the cutting feeling is different from natural teeth, and even if you practice abutment tooth formation and cavity formation, When working, it was often embarrassed by the different cutting feeling and workability. The easy-to-understand expression has a feeling of slipping, and the cutting feeling is very different from natural teeth.

In Japanese Utility Model Laid-Open No. 1-90068, Vickers hardness in which phlogopite crystals [NaMg3 (Si3AlO10) F2] and lithia / alumina / silica-based crystals (Li2O.Al2O3.2SiO2, Li2O.Al2O3.4SiO2) are simultaneously precipitated on the enamel layer. It is composed of glass and ceramics controlled to 350-450, and the root layer is added with white, red and yellow colorants in the polyol (main agent), and further mixed with an isocyanate prepolymer (curing agent) to form a silicone rubber base. It is injected into the mold under vacuum, hardened at room temperature and prepared in advance, and the dentin layer that is interposed between the enamel layer and the root layer is bonded with an opaque color. It shows that it is formed of a resin.

  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 layer is an adhesive resin. Therefore, the cutting feeling of the adhesive was too soft, so it was not durable. Furthermore, there is a description that dentin is formed in the adhesive layer. It is shown that an enamel layer portion and a root layer portion are formed and bonded. It is recognized as dentin by 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 main constituent components, inorganic powder and cross-linked resin are contained in a weight ratio of 20% to 80% to 70% to 30%.

As the inorganic powder constituting the tooth model of the present invention, for example, alumina, zirconia, titania, silica and the like are introduced, and the inorganic powder is not limited to the above compounds, and various inorganic powders can be used.
However, since the cutting feeling is different from that of natural teeth, even when practicing abutment tooth formation and cavity formation, when working in the actual oral cavity, it was often embarrassed by the different cutting feeling and workability. Moreover, only an inorganic powder body is disclosed. In particular, 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.
Conventional tooth models are not in a satisfactory state 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, it was not a tooth model that showed the difference in machinability between the enamel part and the dentin part.

JP-A-5-224591 provides a dental model that can be optimally used for a periodontal disease treatment practice of a dentist. 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.
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 has not been solved from the viewpoint of cutting feeling. In particular, it was not a tooth model that showed the difference in machinability between the enamel part and the dentin part.
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. In particular, it was not a tooth model that showed the difference in machinability between the enamel part and the dentin part.

Japanese Patent Application Laid-Open No. 2004-94049 describes an invention for providing 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.

Up to now, it was not a tooth model that could show the difference in machinability between the enamel part and the dentin part. Furthermore, there is no disclosure as a specific composition for realizing this cutting feeling, and no description is given of a manufacturing method thereof.
Although the jaw model has these problems, no research report has been found.

JP-A-5-241498 JP-A-5-241499, JP 5-241500 A JP 2004-94049 A Japanese Utility Model 1-90068

Although the conventional tooth for jaw model has a natural tooth form, it has a different cutting feeling. In order to experience the cutting feeling of natural teeth, some ideas such as cutting extracted teeth were seen. The extracted tooth is a material from the human body and animals, and there are problems with hygiene. There is a possibility of infection if hygiene is not adequately controlled, and practice must be freely prevented to prevent infection. . Moreover, since it is a natural living body, there is a problem of spoilage, and sufficient caution is required for storage.
There has been a demand for a method for experiencing the cutting feeling of a tooth without using a natural tooth. In particular, there is a demand for a change in the cutting feeling of the dentin portion from the enamel portion of the tooth. There was no way to do it.
As a result of research, it is necessary to use an inorganic fired body to give a cutting feel to natural teeth, but it is difficult to control the hardness of inorganic materials, so the enamel part is controlled while controlling these. And it was difficult to produce the dentin part.

In order to adjust the cutting feeling of the sintered body, it is necessary to match the density, grain shape, and firing temperature of the fired body, but the shrinkage and thermal expansion differ during firing of the enamel part and the dentin part, and cracks and peels off. , Cracking, etc., and further, there is a gap between the dentin part and the enamel part, which may cause chipping during cutting, and the gap conveys a feeling different from the cutting feeling of natural teeth and does not endure use It was.
When the adhesive layer that bonds the enamel part and the dentin part is thick, a different cutting feeling is felt. As a result, the tooth model is greatly separated from the natural tooth.

The present invention relates to a tooth for a jaw and tooth model for therapeutic practice, which comprises a dentin portion and an enamel portion, and after the dentin portion and the enamel portion are prepared, the dentine portion and the enamel portion are bonded to each other. This is a model tooth.
A tooth for a jaw and tooth model, wherein the adhesive of the present invention is an organic resin composition.
The present invention is a tooth for a jaw and tooth model for treatment practice, wherein the dentin portion and the enamel portion are made of an inorganic powder fired body.
Furthermore, the thickness of the adhesive is preferably 1 to 500 μm. More preferably, the thickness is 1 to 300 μm, and further preferably 1 to 200 μm. Furthermore, it is preferable to set it as 1-100 micrometers.
By reducing the adhesive thickness, cutting easily moves to the dentin portion of the sintered inorganic powder, and the cutting feeling with natural teeth is approximated.

The present invention relates to a jaw and tooth model characterized by injection molding using CIM technology, forming a dentin portion and an enamel portion through degreasing and firing steps, and bonding the dentin portion and the enamel portion using an adhesive. This is a method for producing dental teeth.

According to the method of the present invention, both the dentin part and the enamel part can obtain the same cutting feeling as that of the natural tooth, and the cutting feeling that shifts from the enamel part to the dentin part is close to that of the natural tooth. Practice cutting natural teeth easily.
Since the extracted tooth is a material from a living body and has a hygiene problem, a tooth that can be used safely without taking measures such as infection prevention and has a feeling similar to that of the extracted tooth has been demanded. In addition, there is a need for a material that does not require any sanitary management and is free from the risk of corruption.
By forming an abutment tooth and a cavity using the tooth of the present invention, a cutting feeling similar to that of a natural tooth can be experienced quickly, and the formation experience can be easily performed. Moreover, these formation techniques can be acquired quickly.
The jaw model tooth is a substitute for the hardest natural tooth in the human body, and a normal material feels soft at the time of cutting, while a cutting feeling similar to that of a natural tooth can be obtained. A cutting experience similar to that of cutting using diamond abrasives (using an air turbine) rotating at a high speed of 400000 revolutions per minute in the oral cavity is possible.

Since it is in contact with the cutting body that rotates at high speed in molding, compatibility with the jaw is important, and compatibility with enamel and dentin is also required, so it is necessary to use CIM (Ceramic Injection Mold) technology that can be molded precisely. preferable.
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. ing.
Since the tooth of the present invention can be white, ivory, milky white, and translucent, like a tooth, a more realistic cutting experience can be achieved. Preferred are white, ivory and milky white.
You can experience cutting natural tooth models without tasting the soft feeling of the adhesive. You can experience smooth cutting from enamel to dentin.

A tooth for a jaw and tooth model is a tooth used for simulating the practice of treatment in the oral cavity and practicing treatment using a jaw and tooth model in universities, etc., and the present invention cuts and forms teeth. It relates to the case where it is used. In particular, the present invention relates to a tooth having cutting ability similar to that of a natural tooth and used for practicing cavity formation and abutment tooth formation.

The present invention consists in adhering a molded enamel part and a dentin part.
As the resin used for the adhesion of the present invention, a thermosetting resin, a thermoplastic resin, or a chemically polymerizable resin can be used, and among them, a thermosetting resin and a chemically polymerizable resin are preferable. Furthermore, a ceramic adhesive and an epoxy resin are preferable.
Adhesion required for the present invention is preferably that the enamel portion and the dentin portion are bonded together, and there is a portion that is not even bonded or that there are large bubbles that affect the cutting feeling. Absent.

The tooth composition of the present invention is preferably produced from ceramics. The composition of the tooth of the present invention is produced from ceramics or glass such as alumina, zirconia, silica, aluminum nitride, and silicon nitride. Moreover, it is preferable to produce by an alumina type and a zirconia type. 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%. The tooth composition is preferably molded from alumina powder.
Both the enamel part and the dentin part are preferably an inorganic powder fired body.
To adjust the hardness of the enamel part and dentin part, there are methods such as roughening the grain size, increasing the voids, changing the material, changing the firing temperature, changing the mooring time, etc., but the most suitable method Is to change the particle size with the same composition.
The average particle size of the enamel portion is preferably 10 times or more than the average particle size of the dentin portion. When the average particle size of the enamel portion is 1.0 to 10.0 μm, the average particle size of the dentin portion is preferably set to 0.1 to 0.5 μm.
Although the firing temperature varies depending on the composition, when there are many glass components such as silica, the firing temperature is 800 to 1200 ° C., and when alumina is 1200 to 1600 ° C., preferably 1400 to 1550 ° C.

For forming the enamel part and the dentin part, it is preferable to use the CIM technique as a ceramic forming method.
Using CIM technology, the enamel part and the dentin part are injection-molded, and after degreasing and firing processes, the fired enamel part and the dentin part are bonded to the interface using a thermosetting resin or a chemically polymerizable resin. It is also preferable.

The thermoplastic resin used for bonding refers to a resin that can obtain thermoplasticity to the extent that it can be molded by applying heat, and the thermosetting resin refers to a resin that crosslinks and cures when heated. The Specifically, acrylic, styrene, olefin, vinyl chloride, urethane, polyamide, polybutadiene, polyacetal, saturated polyester, polycarbonate, polyphenylene ether and the like can be used.
Polysulfone, polyimide, polyetherimide, polyetheretherketone and the like can also be used as appropriate. In particular, an acrylic type is preferable.

A thermosetting resin is preferred to a thermoplastic resin. A thermosetting resin 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.

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 resin used for the adhesive is preferably a thermosetting resin or a chemically polymerizable resin among thermosetting resins, thermoplastic resins, and chemically polymerizable resins.

A female mold of the enamel part and dentin part of the tooth form was dug out, and a mold capable of injection-molding the target shape was produced. Since both the enamel part and the dentin part are shaped, and shrinkage occurs due to degreasing and firing, the part was largely calculated in advance to prepare a mold. The mold was adjusted for each material.
Using 1 kg of alumina pellets for CIM as the raw material for the enamel part (Al ₂ O ₃ is 26%, SiO ₂ is 44%, average particle size is 0.25 μm, stearic acid is 30%), injection is made into a tooth-shaped mold. Molded to obtain an injection body.
The produced injection body in the form of the enamel portion was degreased and fired (1300 degrees, mooring time 10 minutes) to obtain a sintered body 1-1.
Using 1kg of alumina pellets for CIM (26% Al ₂ O ₃ , 44% SiO ₂ , average particle size 3.0 μm, 30% stearic acid) as a raw material for dentin, injection into dental molds Molded to obtain an injection body.
The produced injection body in the form of a dentin portion was degreased and fired (1000 degrees, mooring time 10 minutes) to obtain a sintered body 1-2.

Using 1 kg of alumina pellets for CIM (68% Al ₂ O ₃ , 2% SiO ₂ , average particle size 0.3 μm, 30% stearic acid) as a raw material for the enamel part, it is injected into a dental mold Molded to obtain an injection body.
The produced injection body in the shape of the enamel portion was degreased and fired (1550 degrees, mooring time 10 minutes) to obtain a sintered body 2-1.
Using 1 kg of alumina pellets for CIM (68% Al ₂ O ₃ , 2% SiO ₂ , average particle size 5.0 μm, 30% stearic acid) as a raw material for dentin, injection into a dental mold Molded to obtain an injection body.
The produced injection body in the form of a dentin portion was degreased and fired (1400 degrees, mooring time 15 minutes) to obtain a sintered body 2-2.

The feeling of cutting of the fired bodies 1 and 2 obtained by joining the enamel portion and the dentin portion of the obtained sintered bodies 1-1, 1-2, 2-1, and 2-2 with various adhesives was confirmed. 30 fired bodies were prepared and tested.
(Epoxy resin)
An epoxy resin to which a catalyst was added was applied to the interface between the enamel part and the dentin part, and was bonded. After leaving for 72 hours, the cutting feeling was confirmed with a diamond bar.
(Ceramic adhesive)
The ceramic adhesive was applied and bonded to the interface between the enamel part and the dentin part. After leaving for 72 hours, the cutting feeling was confirmed with a diamond bar.
(Cement material)
A powder liquid kneading type cement was used which was cured by reacting an ionic polymer with glass. It was applied to the interface between the enamel part and the dentin part. After leaving for 72 hours, the cutting feeling was confirmed with a diamond bar.
(Α-cyanoacrylate monomer adhesive) (abbreviation: α adhesive)
It is an adhesive sold under the popular name Aron Alpha, and is applied to the interface between the enamel part and the dentin part. After leaving for 72 hours, the cutting feeling was confirmed with a diamond bar.

A: The result was as good as natural teeth.
○: Although it was confirmed that it was sufficiently adhered, some chipping occurred.

Compared to the fired body 1, the fired body 2 was closer to the cutting feeling of the natural tooth in both the dentin portion and the enamel portion.
Regarding cutting, both conditions were good. Although the chipping of the cement material and the α adhesive was observed, a cutting feeling similar to that of natural teeth was obtained.

(Comparative Example 1)
A target mold was made by digging out a female mold of the enamel part and dentin part of the tooth form. In the comparative example, an injection mold having a two-layer structure was produced, and a molded body in which a dentin portion and an enamel portion were molded was obtained.
Using 1 kg of alumina pellets for CIM as the raw material for the enamel part (Al ₂ O ₃ is 26%, SiO ₂ is 44%, average particle size is 0.25 μm, stearic acid is 30%), injection is made into a tooth-shaped mold. Molded.
Using 1 kg of alumina pellets for CIM as a raw material for the dentin part (26% Al ₂ O ₃ , 44% SiO ₂ , average particle size 3.0 μm, 30% stearic acid), the enamel part followed by the tooth shape The mold was injection molded to obtain an injection body.
The produced injection body in the form of a tooth was degreased and fired (1100 degrees, mooring time 10 minutes) to obtain a sintered body 3. 30 fired bodies were prepared and tested.

Using 1 kg of alumina pellets for CIM (68% Al ₂ O ₃ , 2% SiO ₂ , average particle size 0.3 μm, 30% stearic acid) as a raw material for the enamel part, it is injected into a dental mold Molded.
Using 1 kg of alumina pellets for CIM (68% Al ₂ O ₃ , 2% SiO ₂ , average particle size 5.0 μm, 30% stearic acid) as a raw material for the dentin part, the enamel part followed by the tooth shape The mold was injection molded to obtain an injection body.
The produced injection body in the form of a tooth was degreased and fired (1500 degrees, mooring time 15 minutes) to obtain a sintered body 4. 30 fired bodies were prepared and tested.

In the sintered bodies 3 and 4, cracks were observed at the boundary between the enamel portion and the dentin portion due to the difference in shrinkage rate, and many objects were not bonded. Breaking and chipping were observed during the cutting. Since the thermal expansion and shrinkage during firing of the dentin portion and the enamel portion are different, it was difficult to produce by this method.
Example 3
The enamel part and the dentin part of the sintered bodies 1-1, 1-2, 2-1 and 2-2 obtained by producing in the same manner as in Examples 1 and 2 were fired using a low-melting glass powder. The feeling of cutting was confirmed by joining.
The case where IP9021 (low melting point glass, 575 ° C. firing) manufactured by Heraus was used as the glass powder was fired body 5, and the case where IP9049 (low melting point glass, firing at 610 ° C.) was used was fired body 6.

Regarding adhesiveness, dentin and enamel bonded together. Although the cutting feeling was adhered, cracks occurred at the interface, and a cutting feeling close to that of natural teeth was not obtained. Although it was confirmed that they were sufficiently adhered, some chipping occurred. Since the bonded glass did not reach the entire interface, an unbonded surface was formed, which seems to have caused chipping or the like.
The sintered bodies 5 and 6 melted the vitreous material by firing, and the dentin portion and the enamel portion were bonded, but the glass portion at the interface was cracked during cutting, and peeling and chipping occurred from the vitreous adhesive layer.
Although problems remain in adhesiveness and chipping as in Examples 1 and 2, there was a great effect on the cutting feeling.

Example 4
The enamel part and the dentin part of the sintered bodies 1-1, 1-2, 2-1 and 2-2 obtained by producing in the same manner as in Examples 1 and 2 are epoxy resin, ceramic adhesive, cement material, The cutting feeling was confirmed by bonding using an α adhesive. However, in order to control the film thickness, alumina film of 700 μm, 400 μm, 350 μm, 250 μm, 150 μm, 50 μm, and 20 μm was mixed with 3% of each adhesive to limit the film thickness of the enamel part and the dentin part.
After preparing the tooth | gear which prescribed | regulated the thickness of the adhesive material layer, it cut | disconnected and measured the adhesive bond layer with the microscope. It was confirmed that it was made to be several tens of microns thicker than the alumina powder used for defining the thickness of each adhesive layer.

Δ: Superior to conventional teeth.
○: Although it was confirmed that it was sufficiently adhered, some chipping occurred.
A: The result was as good as natural teeth.
◎ +: Very good results as natural teeth.

Although depending on the type of adhesive, when the particle size of the alumina powder to be mixed exceeded 700 μm, there was a strong tendency to feel the cutting feeling of the adhesive layer during cutting. If it is about 500μ or less, it can be used for cutting practice. Further, as the adhesive layer became thinner, the feeling of cutting of the adhesive disappeared. In addition, although related to the type of adhesive, the feeling of cutting of the adhesive was greatly reduced from 500 μm or less. Further, it was felt that chipping was reduced from 300 μm or less, and adhesion was strengthened. Further, when the thickness is 200 μm or less, the adhesion is sufficiently performed, and the margin portion can be cut without a sense of incongruity. In addition, the feeling of adhesion from 100 μm or less faded, and the enamel layer shifted to the dentin layer without a sense of incongruity.

Claims (5)

A tooth for a dental model for treatment practice, which consists of a dentin part and an enamel part, and the dentin part and the enamel part are made, and then the dentin part and the enamel part are bonded. For teeth. A tooth for a jaw and tooth model, wherein the adhesive according to claim 1 is an organic resin composition. A tooth for a jaw and tooth model, wherein the adhesive material according to claim 1 has a thickness of 1 to 500 µm. Teeth for a jaw and tooth model for treatment practice,
3. The tooth for a jaw and tooth model according to claim 2, wherein the dentin portion and the enamel portion are made of an inorganic powder fired body. Teeth for a jaw and tooth model for treatment practice,
A step of kneading Al ₂ O ₃ powder having an average particle size of 1 to 8 μm with a binder, molding and baking with a molding machine, and Al ₂ O ₃ powder having an average particle size of 0.1 to 1.0 μm. A tooth for a jaw and tooth model, comprising a step of kneading with a binder, molding and baking with a molding machine, and bonding the dentin portion and the enamel portion with an adhesive.