JP4159494B2 - Method for manufacturing dental teeth for dental practice - Google Patents

Description

  The present invention relates to a method for manufacturing dental training model teeth.

2. Description of the Related Art Conventionally, dental training models having an abutment shape or a cavity shape in a crown portion have been widely used in dental restoration training, prosthesis manufacturing training, and the like in educational fields such as dental universities and dental technician schools. In general, since the abutment form or the cavity form needs to be changed for each case, several to several tens of similar products are required even in the same region. In addition, since dental training education needs to be equal for all students, the shape of the dental training model teeth supplied must have the same shape with as little individual variation as possible.
As a method for efficiently producing such various types of dental training model teeth, for example, there are those described in the following non-patent literature, and the method disclosed here is a liquid thermosetting resin. Is cast into a soft rubber mold to produce an abutment tooth form and a cavity forming form.
Jiro Hasegawa, “Latest Dental Materials and Technologies / Equipment”, CMC Co., Ltd., issued December 14, 2000, pp. 192-193

  However, the technique disclosed in Non-Patent Document 1 is to invert a single model tooth once into a rubber mold, and then mold the molded product a plurality of times using this rubber mold. It takes a lot of time to produce a molded product, and since a soft rubber mold is used, the rubber mold deforms with each molding, and the dimensional accuracy is as high as when a mold is used. There was a problem that it was not possible to obtain a molded product having.

In addition, as a method for accurately producing a dental prosthesis for each patient in the dentistry field, for example, those disclosed in the following Patent Documents 1 to 4 can be cited, and the techniques disclosed in these Patent Documents are In either case, a dental prosthesis is manufactured by cutting from the tooth shape data of the patient.
JP-A-11-128248 JP 7-136191 A JP-A-10-127661 Japanese Patent Laid-Open No. 10-058281

  However, in the method for manufacturing a dental prosthesis disclosed in Patent Documents 1 to 4, the dental prosthesis corresponding to the patient's tooth profile is shaved from the prosthetic soul-like material based on the shape data of each patient. Although it is a technique, in order to cut a prosthesis from a massive material, it takes a lot of waste of raw materials to obtain the desired shape, and the processing time is long, and it is excellent in productivity as an industrial product manufacture It wasn't.

  The present invention provides a method for producing a small number of various types of dental training model teeth in a short time and with a high level of dimensional accuracy.

That is, the method for producing a dental practice model tooth of the present invention is a method for producing a dental practice model tooth formed by artificially imitating an abutment form or a cavity form in a crown part, The method includes a step (step A) of forming an artificial model tooth composed of a crown portion and a root portion artificially imitated, and a step of creating shape data relating to a desired abutment shape or cavity shape (step) B), a step of converting the shape data into cutting data for forming an abutment shape or a cavity shape (step C), and using the cutting data, the abutment shape or the cavity in the crown portion of the artificial model tooth It consists of the process (process D) which carries out the cutting shaping of the form, It is characterized by the above-mentioned.
According to the present invention, in the method for manufacturing a dental training model tooth having the above-described features, the shape data is desired for the artificial model tooth including a crown part and a root part artificially formed. After the abutment form or cavity shape is provided by modeling, the abutment form or cavity shape is obtained by measuring the three-dimensional shape using a three-dimensional shape measuring instrument. is there.
Furthermore, the present invention provides a dental training model tooth manufacturing method having the above-described features, wherein the shape data of the artificial model tooth comprising a crown portion and a root portion artificially imitated. It is obtained by adding shape data relating to a desired abutment form or cavity form to the shape data.
In the present invention, it is preferable that the artificial model tooth including the crown portion and the root portion artificially imitated is formed by an injection molding method using a mold.

  By using the manufacturing method of the present invention, a small number of various types of dental training model teeth can be manufactured in a short time with a high level of dimensional accuracy.

As shown in FIG. 1, a dental training model tooth obtained by the manufacturing method of the present invention includes a crown portion (1) and a root portion (2) that are formed artificially, and at least teeth. The crown has the desired abutment configuration (4) or cavity configuration (3). Fig.1 (a) is a figure which shows an example of the schematic shape of the dental practice-like model tooth in which the healthy form was formed, FIG.1 (b) formed the cavity shape obtained by the manufacturing method of this invention. It is a figure which shows an example of schematic shape of the dental training model tooth, FIG.1 (c) is a figure which shows an example of schematic shape of the dental training model tooth which formed the abutment form.
The abutment form (4) provided in the crown part (1) is a form suitable for mounting of the prosthesis, and is appropriately determined depending on the site of the tooth, the size of the tooth, or the type of the prosthesis. The Moreover, the cavity shape (3) provided in the crown part (1) is also appropriately determined according to the site of the tooth, the size of the tooth, the case, and the like. The cavity shape (3) may be provided not only in the crown portion (1) but also in the root portion (2), and the number thereof is not limited to one.

  Artificial model teeth for which an abutment form and a cavity form are formed, the crown part and root part may be formed of the same material, may be formed of a plurality of materials, Like a natural tooth, it may have a multilayer structure having an enamel layer on the surface and a dentin layer inside. In this case, the enamel layer and the dentin layer that form the crown part may be formed of different materials, may be the same material, but can perform dental education practice closer to natural teeth, The material of the enamel layer is preferably a harder material than the dentin material. The crown (1) is provided with fine irregularities on the surface thereof with a centerline average roughness Ra of 0.1 micrometer or more and less than 10 micrometers, preferably about 0.15 micrometers or more and 5 micrometers, The laser beam may be reflected.

Further, by providing a discolored portion due to caries or deposition on the surface portion, it may be a model tooth that is closer to an actual natural tooth, or a deposit imitating tartar may be provided. Furthermore, it is possible to provide a discolored portion simulating caries at the interface between the enamel layer and the dentin layer, and a pulp cavity may be formed inside the dentin.
The root part of the dental model tooth for dental training may be a single layer structure or a multilayer structure, and has a structure having a plurality of roots closer to natural teeth, or a single root structure obtained by simplifying natural teeth. May be. Further, a pulp cavity or a root canal that simulates a natural tooth may be formed inside.
These dental training model teeth are preferably prepared with a plurality of parts suitable for a human living body such as milk teeth and permanent teeth. For example, in the case of permanent teeth, 32 artificial model teeth are prepared by combining upper and lower jaws, It may be designed to be installed on the jaw model.

As a raw material for such dental training model teeth, generally known injection moldable or compression moldable materials can be used, for example, ceramics or other porcelain or heat such as acrylic, polystyrene, polycarbonate, polyester or the like. Synthetic resin materials such as plasticity, thermosetting such as melamine, urea, unsaturated polyester, phenol and epoxy, polymerizable monomer materials such as trimethylolpropane trimethacrylate and dimethacryloxyethyltrimethylhexamethylenediurethane, and these Main raw materials for glass fiber, carbon fiber, pulp, synthetic resin fiber and other organic and inorganic reinforcing fibers, talc, silica, mica, calcium carbonate, barium sulfate, alumina, glass powder and other fillers, pigments and dyes Colorants such as weathering agents and antistatic agents It can be used those obtained by adding various additives.
Here, in order to obtain a model tooth having a cutting feeling closer to that of a natural tooth, a hard material in which an inorganic material such as silica is filled in the polymerizable monomer material described above is used for the enamel layer of the crown portion, and the dentin layer It is desirable to use a material having a relatively low hardness, mainly made of acrylic, melamine, epoxy, or the like, as a material for the tooth root.
The color tone of these materials is not particularly limited, but is appropriately adjusted to a desired color tone. The method of toning is not particularly limited, and may be adjusted to a desired color tone by appropriately combining various known pigments and dyes.

Next, the method for producing the dental training model tooth of the present invention will be described with reference to the drawings, but the present invention is not limited to this.
First, a raw material is filled and solidified in a mold having the shape of an artificial model tooth composed of a crown portion and a root portion artificially imitated as shown in FIG. A tooth is formed (step A). Here, the mold includes not only a mold made of metal but also a hard resin mold containing a filler used for a prototype mold.
As a molding method, a generally known method of filling and solidifying a material in a mold such as injection molding or compression molding can be used. For example, when a thermosetting resin material is used as the material for the artificial model tooth, it is desirable to mold the artificial model tooth by a generally known injection molding method. A mold (5) as shown in FIG. The resin material (6) softened by heating is filled into a mold maintained at a temperature higher than the curing temperature of the resin material (FIG. 2 (b)), heated and solidified under pressure, and then the mold is opened. Then, by taking out the molded product (FIG. 2C), the artificial model tooth (7) having high dimensional accuracy can be efficiently molded (FIG. 2D).

In addition, a material in which powdery alumina and a resin component such as wax are mixed is filled and solidified in the mold as described above, and the taken-out molded product is heated to evaporate the wax, and then baked and hardened at a high temperature. By using this method, it is also possible to mold an artificial model tooth made of ceramics with high dimensional accuracy.
Furthermore, it is possible to use a method of molding based on three-dimensional shape data using a three-dimensional molding machine using a photo-curing resin or a three-dimensional molding machine of various materials, but these techniques are used for molding. Since it takes a relatively long time, it is generally used when it is applied to artificial model tooth molding that cannot be molded by injection molding or compression molding.

Next, shape data having a desired abutment shape or cavity shape is created (step B). As a method of creating shape data, it is also possible to obtain a pre-shaped abutment shape or cavity shape by measuring the shape with a three-dimensional shape measuring instrument, and creating a desired shape using a three-dimensional CAD or the like It is also possible to do.
In the former case, by using an artificial model tooth that is a basis for cutting and shaping the above-described abutment form or cavity shape, three-dimensional shape measurement is performed on the artificial model tooth obtained by shaping a desired abutment form or cavity shape. The shape data including the abutment form or the cavity form can be easily obtained. As a method for acquiring shape data, a generally known contact type three-dimensional shape measuring device (9) as shown in FIG. 3 or a non-contact three-dimensional shape measuring device using laser light or halogen light is used. Can do.
In the latter case, it is possible to create a desired abutment shape or cavity shape on the data using a three-dimensional CAD or the like, but more faithful shape data can be obtained. Measure the shape of the necessary part including the crown part of the artificial model tooth that is the basis for cutting and shaping the abutment form or cavity shape, and change the obtained shape data to a shape that includes the abutment form or cavity shape on CAD It is desirable to obtain desired shape data.

  Next, the acquired shape data of the abutment shape or the cavity shape is converted into NC data for cutting on the CAM (step C). In order to minimize the cutting time, it is desirable to create cutting NC data of only the acquired abutment shape portion or cavity shape portion. It is also possible to duplicate the created NC data at a plurality of positions.

Next, an abutment form or a cavity form is cut from the artificial model tooth using the cutting NC data (step D). As a technique for performing the cutting modeling, a predetermined type of a processing machine that performs the cutting modeling based on NC data such as a vertical or horizontal NC cutting apparatus or a machining center that performs cutting using a cutter (11) as shown in FIG. An artificial model tooth based on the position is fixed, and cutting modeling is performed based on NC data. Here, the cutting modeling includes laser cutting and the like in addition to cutting with a rotary blade, grinding with a rotating grindstone, or grinding with ultrasonic vibration.
The method of attaching the artificial model tooth to the machine for cutting and shaping is not particularly limited. For example, a method of fixing the bottom and root of the artificial model tooth with a screw (10), a method of clamping the root, and a root The method is suitably selected from a method of vacuum adsorption, a method of fixing a metal to a tooth root portion, and fixing by a magnetic force.
The number of artificial model teeth to be cut and shaped may be one or plural, but a plurality of artificial model teeth are fixed to the cutting molding machine in terms of obtaining higher productivity. Is desirable. The plurality of artificial model teeth may all be the same site or may be different sites, and are appropriately determined in consideration of productivity.

The direction in which the artificial model teeth are fixed may be perpendicular or horizontal to the axial direction in which cutting and shaping are performed, or may have a free angle, depending on the desired abutment form or cavity form. It is determined. In addition, the jig (8) is used for fixing the artificial model teeth to the cutting molding machine, and further, the cutting molding machine is provided with a rotation mechanism that can rotate the jig (8) about a certain axis. By providing the jig fixing portion (12), the fixing direction of the artificial model teeth can be made variable, and the productivity can be further increased.
For example, a jig fixing part (12) as shown in FIG. 5 is provided in a cutting molding machine, and at least a part of the root part (2) of the artificial model tooth (7) can be inserted and fixed to the jig fixing part (12). Such a jig (8) is attached by being rotated by a jig rotating device (13). Then, as shown in FIG. 5, after fixing a plurality of artificial model teeth (7) to this jig (8), one artificial model tooth (7) is used one by one using a cutting blade (11), or Cut multiple pieces at the same time. By using a jig as illustrated in FIG. 5, many dental training model teeth can be manufactured within a limited range. Further, in the present invention, as shown in FIGS. 6A to 6C, the artificial model tooth (7) is fixed to the artificial model tooth fixing jig (8), and the jig (8) is sequentially attached. The artificial model tooth (7) may be cut from various directions by rotating, and in this case, the crown part and / or root part of the artificial model tooth (7) based on predetermined cutting data. Therefore, the desired abutment shape or cavity shape can be formed in a relatively short time, so that the productivity is extremely high.

  The cutting blade (11) used for cutting shaping is appropriately selected depending on the desired abutment shape or cavity shape. For example, a cutting tool for metal processing such as a general end mill, ball end mill, taper end mill, radius end mill, etc. In addition, a grindstone in which alumina powder or the like is hardened with a resin material, or a dental carbide bar or diamond bar in which diamond abrasive grains are electrodeposited on a metal rod can be used. In the present invention, the size and shape of the cutting blade are also appropriately selected according to the abutment form or the cavity form.

By using such a manufacturing method of the present invention, a dental training model tooth having an abutment shape or a cavity shape with a wide variety of small quantities can be manufactured in a short time and with a high level of dimensional accuracy.
The dental training model tooth obtained using the manufacturing method of the present invention may be supplied as a product as it is, and the crown surface, the abutment form part or the cavity form part may be replaced with a pencil, ink, etc. It may be supplied after being subjected to post-processing such as coloring with a laser or marking the surface with a laser. It is also possible to print the product number, manufacturing number, etc. on the root of the dental training model tooth using an inkjet marker, a laser marker, or the like.

[Example 1]
The shape of the molar crown and root of the molar was formed, and the mold heated to about 165 ° C. was attached to a thermosetting resin injection molding machine (manufactured by Matsuda Seisakusho) with a clamping force of 75T. Thereafter, milky white melamine resin softened by heating at about 90 ° C. was filled in the mold and cured by heating for about 50 seconds, and then the mold was opened and the artificial model tooth made of melamine resin was taken out.
Next, an abutment form was formed on the occlusal surface of the artificial model tooth made of melamine resin using a dental technician's router and a carbide bar.
This artificial model tooth that forms the abutment form is attached to a jig of a method for fitting the root part, and a contact type three-dimensional view from a direction substantially coinciding with the tooth axis so as to include the abutment form of the artificial model tooth. Shape measurement was performed with a shape measuring instrument (manufactured by Advance).

The obtained shape data was processed into polygon data by CAD (manufactured by Delcam), and the processing locus and NC data were calculated on CAM (manufactured by Delcam) based on this data. At this time, the calculation of the machining trajectory was set to a minimum area necessary for cutting the measured cavity. A blade end mill (manufactured by Nisshin Tool Co., Ltd.) having a diameter of 0.6 mm and an effective length of 6 mm was used as the blade, and the cutting conditions were a rotation speed of 30000 rpm and a feed rate of 1200 mm / min.
Next, a new artificial model tooth was fixed to a jig used for measurement before, and this jig was attached to a predetermined position of a vertical machining center (manufactured by DIGMA). NC data calculated by the CAM was taken into the machining center and cut in the same direction as the measurement axis. This artificial model tooth attachment to cutting was repeated several times to produce a dental training model tooth having an abutment form. The time required for obtaining the shape data was about 30 minutes, and the time required for calculating the NC data from the shape data was about 60 minutes. Further, the time required for cutting per piece was about 1 minute.
As a result of measuring the maximum length of the dental training model tooth thus obtained, the difference from the artificial model tooth forming the base abutment form is within 0.03 mm, and the manufactured dental training model tooth The variation between the model teeth was within 0.02 mm, and the dimensional accuracy was good.

[Example 2]
The shape of the molar crown and root of the molar was formed, and the mold heated to about 165 ° C. was attached to a thermosetting resin injection molding machine (manufactured by Matsuda Seisakusho) with a clamping force of 75T. Thereafter, milky white melamine resin softened by heating at about 90 ° C. was filled in the mold and cured by heating for about 50 seconds, and then the mold was opened and the artificial model tooth made of melamine resin was taken out.
Next, the artificial model tooth made of melamine resin is attached to a jig that engages the root of the tooth, and the occlusal surface is shaped with a contact type three-dimensional shape measuring instrument (manufactured by Advance Co., Ltd.) in a direction that substantially matches the tooth axis. Measurement was performed.

The obtained shape data was processed into polygon data by CAD (manufactured by Delcam), the occlusal surface data was deformed, and an abutment form was formed on the occlusal surface on the data. The machining trajectory and NC data were calculated on CAM (manufactured by Delcam) based on the data forming this abutment form. At this time, the calculation of the machining trajectory was set to a minimum area necessary for cutting the measured cavity. A blade end mill (manufactured by Nisshin Tool Co., Ltd.) having a diameter of 0.6 mm and an effective length of 6 mm was used as the blade, and the cutting conditions were a rotation speed of 30000 rpm and a feed rate of 1200 mm / min.
Next, a new artificial model tooth was fixed to a jig used for measurement before, and this jig was attached to a predetermined position of a vertical machining center (manufactured by DIGMA). NC data calculated by the CAM was taken into the machining center and cut in the same direction as the measurement axis. This artificial model tooth attachment to cutting was repeated several times to produce a dental training model tooth having an abutment form. The time required to calculate the NC data from the shape data was about 60 minutes. Further, the time required for cutting per piece was about 1 minute.
As a result of measuring the maximum length of the dental training model tooth thus obtained, the difference from the shape data as a basis is within 0.02 mm, and there is no variation between the manufactured dental training model teeth. It was within .02 mm, and the dimensional accuracy was good.

[Comparative Example]
The root part bottom surface of the artificial model tooth in which the abutment form used in Example 1 was formed was fixed to the substantially central part of a φ50 mm flat plate, and a frame was formed on the outer periphery of the φ50 mm flat plate using a commercially available gum tape. Next, until the artificial model teeth are completely buried, a two-component room-temperature-curing silicone resin (addition polymerization type) is poured, and the vacuum-defoamed material in the vacuum chamber is naturally cured at room temperature. . After the natural curing was completed, the silicone resin was completely cured in an oven maintained at 60 ° C. After the silicone resin was completely cured, the artificial model tooth on which the base abutment shape was formed was removed. The silicon resin mold in which the cavity was formed was turned upside down, and an epoxy resin was poured into the cavity formed in the silicon resin. After vacuum defoaming of the epoxy resin, the epoxy resin was naturally cured. After the natural curing was completed, the epoxy resin was completely cured in an oven maintained at 60 ° C. After the epoxy resin was completely cured, the dental training model tooth in which the abutment form was formed was taken out from the silicon resin, and the root of the root portion was prepared with a 180th sandpaper.
From the casting of the epoxy resin to the finishing of the bottom surface of the root portion was repeated several times, a dental training model tooth having an abutment form was manufactured. The time required for producing the silicon resin mold was about 480 minutes including the curing time. Moreover, the time required for casting per one piece was about 360 minutes including the curing time.
As a result of measuring the maximum length of the dental training model tooth thus obtained, the difference from the artificial model tooth forming the base abutment form is about 0.1 mm on average, and the manufactured dental The variation between the model teeth for training was 0.2 mm at the maximum, and the dimensional accuracy was inferior.

Fig.1 (a) is a figure which shows an example of the schematic shape of the dental practice-like model tooth in which the healthy form was formed, FIG.1 (b) formed the cavity shape obtained by the manufacturing method of this invention. It is a figure which shows an example of schematic shape of the dental training model tooth, FIG.1 (c) is a figure which shows an example of schematic shape of the dental training model tooth which formed the abutment form. FIG. 2A is a cross-sectional view showing an example of an artificial model tooth molding die, and FIG. 2B shows a state in which the material is filled and solidified in the artificial model tooth molding die. FIG. 2 (c) is a sectional view showing a state where the artificial model tooth molding die is opened and the molded product is taken out, and FIG. 2 (d) is an example of the molded artificial model tooth. FIG. FIG. 3 is a cross-sectional view showing an example of the shape measurement of the cavity shape of the dental training model tooth in which the cavity shape is formed. FIG. 4 is a cross-sectional view showing an example of a state in which a sinus shape is cut and formed on an artificial model tooth by a cutting molding machine. FIG. 5 is a diagram illustrating an example of an artificial model tooth fixing jig. Fig.6 (a) is a figure which shows an example of the state which has cut the artificial model fixed to the artificial model fixing jig from the occlusal surface direction, FIG.6 (b) was fixed to the artificial model fixing jig. It is a figure which shows an example of the state which is cutting the artificial model from the mesial plane direction, FIG.6 (c) is an example of the state which is cutting the artificial model fixed to the artificial model fixing jig from the centrifugal plane direction. FIG.

Explanation of symbols

1: crown part 2: tooth root part 3: cavity shape 4: abutment form 5: mold for artificial model tooth molding 6: artificial model tooth material 7: artificial model tooth 8: artificial model tooth fixing jig 9: three-dimensional shape Measuring instrument 10: Artificial model tooth fixing screw 11: Cutting blade 12: Jig fixing part 13: Jig rotating device 14: Runner

Claims (3)

A method for manufacturing a dental practice model tooth in which at least a crown shape or a cavity shape is artificially modeled at a crown part, and the method is an artificially modeled tooth A step of forming an artificial model tooth composed of a crown portion and a root portion, a step of creating shape data relating to a desired abutment shape or cavity shape, and the shape data into cutting data for forming the abutment shape or cavity shape A method for producing a dental tooth for dental training, comprising a step of converting, and a step of cutting and shaping an abutment form or a cavity form on at least a crown portion of the artificial model tooth using the cutting data. After the shape data gives a desired abutment form or cavity shape to the artificial model tooth composed of a crown part and a tooth root part imitating artificially by shaping, the abutment form or cavity form is provided. The method for manufacturing a dental tooth for dental training according to claim 1, wherein the dental tooth is obtained by measuring a three-dimensional shape using a three-dimensional shape measuring instrument. The shape data is provided with shape data relating to a desired abutment shape or cavity shape on the shape data of the artificial model tooth composed of a crown portion and a root portion artificially imitated. The method for producing a dental tooth for dental training according to claim 1, wherein the dental tooth is obtained by the following method.

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