JP2011085614A - Tooth model and method for manufacturing the same - Google Patents

Abstract

Disclosed is a tooth model or a method of manufacturing the tooth model that is particularly suitable for training in root canal treatment by providing the realistic properties of the pulp cavity.
[Solution]
The method for producing a tooth model according to the present invention includes (a) a step of selectively irradiating a photocurable liquid composition with light to form a first hardened layer constituting one section of the tooth model; ) One cross section of a tooth model on one surface of the first hardened layer by applying the photocurable liquid composition to one surface of the first hardened layer and selectively irradiating light Forming a second hardened layer comprising:
And a tooth model having a dental pulp cavity is formed by repeating the step (b).
[Selection] Figure 3

Description

  The present invention relates to a tooth model for practicing root canal treatment and a manufacturing method thereof.

  When a dental disease such as caries progresses, the lesion may reach the dental pulp through enamel and dentin. If the pulp becomes infected with bacteria, it can cause pulpitis. Since pulpitis is generally impossible to cure (irreversible), it is necessary to remove the pulp (root extraction) by root canal treatment. As a conventional method of root canal treatment, there is a method of scraping the dental pulp infected with bacteria with an instrument such as a reamer, a file, etc., followed by a series of root canal treatments such as patching and filling, and finally restoring a crown . Such root canal treatments occupy most of dental treatments and require advanced techniques. Therefore, various tooth models for dentistry students to practice root canal treatment have been proposed.

  For example, Patent Document 1 discloses a dental pulp cavity made of silicone rubber obtained by injecting a resin mixture into a female mold for a dental model, and fixing and curing the dental cavity-shaped silicone rubber at the center of the female mold. A tooth model having a part has been proposed. Patent Document 2 proposes a tooth for a jaw and tooth model using an innocent material such as alumina or gypsum.

JP-A-5-241498 JP 2006-163330 A

  However, although the tooth model obtained by the above-mentioned conventional technique is similar to natural teeth in terms of machinability, it is not suitable for practical training in terms of workability, especially because it lacks realism in the pulp cavity. It was. Therefore, as a model for practicing root canal treatment, there was a fact that extracted natural teeth were still used. The use of natural teeth makes it possible to practice full-fledged root canal treatment, but there is a problem that the state of individual teeth is not constant.

  Some embodiments according to the present invention provide a tooth model particularly suitable for training of root canal treatment or a method of manufacturing the tooth model by providing the realistic property of the pulp cavity by solving the above-described problems. is there.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1]
One aspect of the method for producing a tooth model according to the present invention is:
(A) a step of selectively irradiating the photocurable liquid composition with light to form a first cured layer constituting one section of the tooth model;
(B) Applying the photocurable liquid composition to one surface of the first hardened layer, and selectively irradiating the surface with a tooth model on one surface of the first hardened layer. Forming a second hardened layer constituting one cross section;
Including
A tooth model having a dental pulp cavity is formed by repeating the step (b).

[Application Example 2]
In application example 1,
(C) It may further include a step of removing the photocurable liquid composition remaining in the second cured layer.

[Application Example 3]
One aspect of the tooth model according to the present invention is:
A dental pulp cavity is formed by the method for manufacturing a tooth model described in Application Example 1 or Application Example 2.

[Application Example 4]
In application example 3,
The root canal diameter in the pulp cavity can be 0.1 mm or more and 50 mm or less.

[Application Example 5]
In application example 3 or application example 4,
The apical hole diameter in the pulp cavity can be 0.1 mm or more and 50 mm or less.

[Application Example 6]
In any one of Application Examples 3 to 5,
A portion of 0.5 mm to 3 mm can be curved from the apical hole in the dental pulp cavity.

[Application Example 7]
In any one of Application Example 3 to Application Example 6,
The pulp cavity can have a branch structure.

  According to the method for manufacturing a tooth model according to the present invention, a tooth model having cutting ability and workability similar to that of a natural tooth can be manufactured by providing the real property of the pulp cavity portion. According to such a tooth model, dentistry students can practice a series of root canal treatments, and the same effects as when practiced using natural teeth can be obtained.

It is sectional drawing which showed typically the manufacturing apparatus used for the manufacturing method of the tooth model which concerns on this Embodiment. It is sectional drawing which shows a process (a) typically. It is sectional drawing which shows a process (b) typically. It is a perspective view which shows typically the tooth model which concerns on this Embodiment. It is the conceptual diagram which showed typically an example of the electrical root canal length measuring method. It is a perspective view which shows typically the tooth model obtained by the present Example.

  Hereinafter, preferred embodiments of the present invention will be described. Embodiment described below demonstrates an example of this invention. In addition, the present invention is not limited to the following embodiments, and includes various modifications that are implemented within a range that does not change the gist of the present invention.

1. Manufacturing method of tooth model The manufacturing method of the tooth model according to the present embodiment,
(A) a step of selectively irradiating the photocurable liquid composition with light to form a first cured layer constituting one section of the tooth model;
(B) Applying the photocurable liquid composition to one surface of the first hardened layer, and selectively irradiating the surface with a tooth model on one surface of the first hardened layer. Forming a second hardened layer constituting one cross section;
And a tooth model having a dental pulp cavity is formed by repeating the step (b).

  Hereinafter, the manufacturing apparatus and each process will be described in this order.

1.1. Manufacturing Device FIG. 1 is a cross-sectional view schematically showing a manufacturing device 100 that can be used in the method for manufacturing a tooth model according to the present embodiment.

  The manufacturing apparatus 100 includes a container 10, a support stage 12, a light source 16, and a light irradiation unit 18 as basic configurations.

  The container 10 is filled with an appropriate amount of the photocurable liquid composition 20. The photocurable liquid composition 20 may be a liquid composition that is rapidly cured by light such as a laser beam. However, the tooth model is required to have appropriate hardness (cutability), contrast and heat resistance. Therefore, the photocurable liquid composition includes a radical photopolymerization initiator / a composition based on an acrylic monomer, a composition based on a radical photopolymerization initiator / epoxy acrylate monomer, a cationic system A composition containing a photopolymerization initiator / epoxy monomer as a main component and a composition containing a cationic photopolymerization initiator / oxetane monomer as a main component are preferable. Examples of the commercially available photocurable liquid composition 20 include an oxetane photocurable resin (trade name “SCR-950”, manufactured by JSR Corporation), and an epoxy photocurable resin (trade name “SCR-751”). ”, Manufactured by JSR Corporation), and by using these, a tooth model having high definition and toughness can be formed.

  The support stage 12 is provided inside the container 10 and can be moved up and down inside the container 10. The operation of the support stage 12 can be controlled by a control unit described later.

  The light source 14 is for generating light such as a laser beam. As the light source 14, for example, a light excitation laser, a metal halide lamp, a hyper metal halide lamp, an LED light source, or the like can be used.

  The light irradiation unit 16 is for selectively irradiating light generated by the light source 14. The light irradiation unit 16 is not particularly limited, and the following means can be employed. For example, (1) means for irradiating a photocurable liquid composition while scanning convergent light obtained using a laser beam or a lens, a mirror, etc., and (2) using a mask having a light transmissive portion of a predetermined pattern. , Means for irradiating the photocurable liquid composition with non-converging light through the mask, (3) using a light guide member formed by bundling a large number of optical fibers, and providing an optical fiber corresponding to a predetermined pattern in the light guide member (4) means for controlling ON / OFF of light irradiation with each mirror as a pixel using a digital mirror device, and the like can be employed. Further, in the means using the mask, a mask that electrochemically forms a mask image composed of a light transmitting region and a light non-transmitting region in accordance with a predetermined pattern is used according to the same principle as the liquid crystal display device. You can also

  In the above, since the tooth model has a fine portion such as a pulp cavity portion and high dimensional accuracy is required, as a means for selectively irradiating the photocurable liquid composition with a spot, It is preferable to employ means for scanning a laser beam having a small diameter. The light irradiation surface (for example, the scanning plane for convergent light) may be either the liquid surface of the photocurable liquid composition or the contact surface with the vessel wall of the translucent container. In the case where the liquid surface of the photocurable liquid composition or the contact surface with the container wall is used as the light irradiation surface, light can be irradiated directly from the outside of the container or through the container wall.

  The manufacturing apparatus 100 may further include a computer for inputting three-dimensional data, a control unit for controlling operations of the support stage 12 and the light irradiation unit 18 based on the data, a recoater for leveling the liquid level, and the like. As a result, a more accurate tooth model can be formed.

1.2. Step (a)
This step is a step of forming a first hardened layer constituting one section of the tooth model by selectively irradiating the photocurable liquid composition with light. FIG. 2 is a cross-sectional view schematically showing the step (a).

  First, in this step, the photocurable liquid composition 20 is supplied onto the support stage 12 by lowering (sinking) the support stage 12 from the gas-liquid interface 22 of the photocurable liquid composition 20 by a minute amount. A thin layer of the photocurable liquid composition 20 is formed.

  Next, as shown in FIG. 2, the first hardened layer 24 is formed by selectively irradiating the thin layer with light such as a laser beam from the light irradiation unit 18. At this time, the photocurable liquid composition 20 having a depth of 0.03 mm to 1 mm from the gas-liquid interface 22 can be cured. The thickness of the 1st hardening layer 24 can be adjusted with the intensity | strength of the light irradiated from the light irradiation part 18, the thickness of the photocurable liquid composition 20, etc. FIG. As described above, the first hardened layer 24 constituting one cross section of the tooth model is formed.

1.3. Step (b)
In this step, the photocurable liquid composition is applied to one surface of the first hardened layer, and selectively irradiated with light, whereby the tooth model is applied to one surface of the first hardened layer. It is a process of forming the 2nd hardened layer which constitutes one section. FIG. 3 is a cross-sectional view schematically showing the step (b).

  First, the support stage 12 is lowered (sedged) by a small amount, the photocurable liquid composition 20 is supplied onto the first cured layer 24, and a thin layer of the photocurable liquid composition 20 is formed again. To do.

  Next, as shown in FIG. 3, the thin layer is selectively irradiated with light such as a laser beam from the light irradiation unit 18, and continuously and integrally on the first hardened layer 24. A second hardened layer 26 is further formed so as to be laminated. At this time, the photocurable liquid composition 20 having a depth of 0.03 mm to 1 mm from the gas-liquid interface 22 can be cured. The thickness of the 2nd hardened layer 24 can be adjusted with the intensity | strength of the light irradiated from the light irradiation part 18, the thickness of the photocurable liquid composition 20, etc. FIG. As described above, the second hardened layer 26 constituting one cross section of the tooth model is formed.

  Then, by repeating this step (b) a predetermined number of times with or without changing the light irradiation pattern, a tooth model in which a plurality of continuous hardened layers are integrally laminated can be formed. . Here, after the specific portion of the photocurable liquid composition 20 is cured, the cured portion is moved continuously or stepwise from the uncured portion to the uncured portion by moving the light irradiation position (irradiation surface). A three-dimensional shape of a tooth model having a pulp cavity is laminated. The irradiation position can be moved by various methods. For example, any one of the container 10, the light irradiation unit 18, and an already cured portion of the photocurable liquid composition 20 is moved, or the container 10 is photocurable. Examples thereof include a method of additionally supplying the liquid composition 20.

  Moreover, in this process, you may form the upper part and lower part of a tooth model separately, respectively. By separately forming the upper part and the lower part of the tooth model, the uncured photocurable liquid composition 20 accumulated in the pulp cavity can be easily removed. After removing the photocurable liquid composition 20, the target tooth model can be obtained by bonding the upper and lower parts of the tooth model.

1.4. Step (c)
This step is an optional step and is a step of removing the photocurable liquid composition remaining in the second cured layer.

  The tooth model obtained by the above-mentioned process is taken out from the container 10, and after removing the uncured photocurable liquid composition 20 remaining on the surface, it is washed as necessary. Here, as the cleaning agent, alcohol-based organic solvents represented by alcohols such as isopropyl alcohol and ethyl alcohol; ketone-based organic solvents represented by acetone, methyl ethyl ketone, etc .; aliphatic organic solvents represented by terpenes An ester organic solvent represented by ethyl acetate and the like.

1.5. Step (d)
This step is an optional step and is a step of accelerating the curing of the photocurable composition obtained by the aforementioned step.

  The surface of the cleaned tooth model obtained by the above-described process is irradiated with an ultraviolet lamp, and / or the cleaned tooth model is stored in a hot air dryer. Here, the drying temperature is preferably 30 to 120 ° C. and the holding time is preferably 1 to 10 hours. However, if the temperature change in the heating or cooling step is gradually performed, deformation during drying can be prevented, which is more preferable.

1.6. Others In order to enhance the practice effect of root canal treatment for dentistry students, the dental pulp cavity portion of the tooth model produced by the above-described steps may be colored with a pigment. As a method of coloring the dental pulp cavity with a pigment, for example, by putting a colored liquid in which the pigment is dissolved in a bottle, and lowering the internal pressure of the bottle while the obtained dental model is immersed in the colored liquid The dental pulp cavity can be colored. When only the pulp cavity portion is desired to be colored, only the pulp cavity portion can be colored by injecting a coloring liquid into the pulp cavity portion and allowing it to stand still.

2. Tooth model The tooth model according to the present embodiment has a pulp cavity formed by the above-described method for manufacturing a tooth model. According to the method for manufacturing a tooth model described above, a tooth model is formed by laminating a plurality of hardened layers having a thickness of about 0.03 mm to 1 mm. Therefore, a fine three-dimensional structure such as a dental pulp cavity is formed inside the tooth model. The target shape can be formed.

  FIG. 4 is an example of a tooth model according to the present embodiment. In FIG. 4, the shape of the pulp cavity located inside the tooth model 200 is represented by a solid line, and the entire structure of the tooth model 200 is represented by a broken line. As shown in FIG. 4, the tooth model 200 includes a dental pulp cavity portion 30 formed therein, a dental crown portion 40 containing dentin and enamel surrounding the dental pulp cavity portion 30, and the dental pulp cavity portion 30. And a root 50 including the surrounding dentin. The pulp cavity portion 30 has a medullary portion 32, a root canal 34 extending from the medullary portion 32 toward the root of the root, and a periapical hole 36 present at the end of the root.

  Although not shown, the root canal 34 may have a so-called side branch that branches from the main root canal, may have a side branch that connects the root canals, or further from the root canal that connects the root canals. It may be branched. In addition, the realistic property of the dental pulp cavity part 30 can be provided by making the root canal 34 into a curved shape. In particular, by bending the root canal 34 of 0.5 mm to 3 mm from the apical hole 36, a structure similar to a natural tooth can be constructed.

  For the root canal 34, as in the classification reported by Weine, (I) when the root canal entrance is 1 root canal and the exit is 1 root canal, (II) the root canal entrance is 2 root canals and the exit is 1 root canal, (III) 2 root canals with 2 root canals and 2 exits, (IV) 1 root canal with 2 root canals, 2 outlets, etc. Although there are extremely complicated root canal systems, such a complex root canal system can be constructed in the tooth model 200. Further, the root canal diameter and apical hole diameter can be arbitrarily designed within a range of, for example, 0.1 mm or more and 50 mm or less, but the root canal diameter of the root canal inlet and outlet is constructed narrower than the central part of the root canal. Thereby, the real property of the pulp cavity part 30 can be further provided.

  Further, although not shown, the apical hole 36 is also branched and has a so-called apical branch.

  The tooth model according to the present embodiment can have not only a shape similar to a healthy tooth but also a shape that reproduces a pathological image. As a tooth model having a shape that reproduces a pathological image, for example, a tooth model that reproduces a state in which caries has progressed, a tooth model that reproduces a state in which tartar has adhered, and root absorption (a state in which the tip of the root is dissolved) )) Is reproduced. As a tooth model that reproduces the state in which the caries have progressed, a tooth model that reproduces a state having an intrinsic caries that has been difficult to produce in the past can be used. The caries portion is reproduced by forming a low-density portion by, for example, a method of forming an uncured gap of about 0.1 mm in a mesh shape or a method of three-dimensionally stacking blocks of several hundred μm. be able to.

  In addition, the tooth model according to the present embodiment is a tooth model that reproduces an incised tooth (intradental tooth) in which a part of the enamel and dentin of the crown part is deeply invaded inside the pulp. It is also possible to reproduce a special shape such as a tooth model that reproduces another branched root (sub-root) different from the tooth root, or a tooth model that reproduces the groove. Furthermore, the jawbone for supporting the tooth model may be reproduced.

  In the practice of dentistry students, an electrical root canal length measurement method is sometimes performed using a tooth model. At this time, if the tooth model according to the present embodiment is further provided with a structure for supporting the tooth model, the tooth model can be fixed to the electrical root canal length measuring apparatus. This makes it easier for dental students to practice. FIG. 5 is a conceptual diagram schematically showing an example of an electrical root canal length measurement method. As shown in FIG. 5, the tooth model 202 is provided with a fixing member 60. The container 70 is filled with physiological saline, and is arranged so that a part of the tooth model 202 is immersed in the physiological saline. By setting it as such a structure, since the tooth model 202 can be easily fixed to the container 70, operation of the electrical root canal length measuring method becomes simple. Note that the fixing member 60 and the container 70 may be fixed with screws or the like.

  The tooth model according to the present embodiment can be formed not only to form the pulp cavity portion but also to have a shape similar to that of a natural tooth by incorporating the above-described features. As a result, a dental model having a pulp cavity portion having the same or similar shape as that of a natural tooth can be obtained, so that dentistry students can perform a full-scale practice of root canal treatment and practiced using natural teeth. The same effect as the case can be obtained.

  Furthermore, in actual medical practice, root canal treatment is performed based on radiographs. However, when training is performed using extracted natural teeth, as many radiographs are required. However, since the tooth model according to the present embodiment can mass-produce a model having the same shape, it is possible to practice root canal treatment of a dentist student simply by duplicating one X-ray photograph.

3. Examples Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

3.1. Photocurable liquid composition As the photocurable liquid composition, “SCR-950” (manufactured by JSR Corporation, oxetane-based photocurable resin) was used.

3.2. Manufacture of tooth models 3.2.1. Production apparatus An optical modeling system “SCS-1000H” (manufactured by Sony Corporation, He—Cd laser) was used. The optical modeling system “SCS-1000H” is an apparatus having the basic configuration of the manufacturing apparatus 100 illustrated in FIG. 1, and thus description of common members is omitted.

3.2.2. Manufacturing Method First, a natural tooth shape as a sample was created as a three-dimensional CAD solid model and converted into an STL file. Next, the STL-converted file was sliced and converted into contour line data to create contour data for each cross section.

  The stereolithography system “SCS-1000H” was installed, and the photocurable liquid composition “SCR-950” was placed in the container. Based on the obtained contour line data, the He-Cd laser emitted from the light irradiation part scanned the thin layer surface of the photocurable liquid composition on the support stage, thereby depicting one cross-sectional shape of the tooth model. . The portion irradiated with the He—Cd laser was cured from a liquid to a solid, and a cross-section for one layer was formed on the support stage. Next, the support stage was lowered each time one layer was formed, and several cross-sectional bodies were laminated continuously.

  By repeating this operation, a three-dimensional model of the tooth model was completed. Finally, the support stage was raised and the tooth model was taken out. The obtained tooth model was washed with an ultrasonic cleaner and alcohol and then dried by air blow to obtain a tooth model having a pulp cavity.

3.3. Tooth Model FIG. 6 is a perspective view schematically showing a tooth model 204 obtained in this example. In FIG. 6, the shape of the dental pulp cavity located inside the tooth model 204 according to the present embodiment is represented by a solid line, and the entire structure of the tooth model 200 is represented by a broken line. As shown in FIG. 6, the tooth model 204 includes a dental pulp cavity portion 30 formed therein, a dental crown portion 40 containing dentin and enamel surrounding the dental pulp cavity portion 30, and the dental pulp cavity portion 30. And a root portion 50 including the surrounding dentin. The pulp cavity portion 30 had a medulla portion 32, a root canal 34 extending from the medulla portion 32 toward the root of the root, and a periapical hole 36 present at the end of the root. When the maximum pore diameter of the root canal 34 of the tooth model 200 was measured, it was 11 mm. Moreover, when the maximum hole diameter of the apical hole 36 of the tooth model 200 was measured, it was 4 mm. Furthermore, it was recognized that the part which entered about 2 mm from the apical hole 36 is curved.

  As described above, a tooth model having a shape similar to that of a natural tooth could be manufactured by the method for manufacturing a tooth model according to this example.

3.4. Usage Test Ten dental students practiced root canal treatment using the tooth model 204 obtained as described above. As a result, the tooth model 204 has a high realistic property of the pulp cavity portion 30 and has cutting performance and workability (such as filing and reaming) almost the same as those of natural teeth, and is suitable for practical training of root canal treatment. I found out.

  The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the present invention includes substantially the same configuration (for example, a configuration having the same function, method, and result, or a configuration having the same purpose and effect) as the configuration described in the embodiment. In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same object. In addition, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

DESCRIPTION OF SYMBOLS 10 ... Container, 12 ... Support stage, 16 ... Light source, 18 ... Light irradiation part, 20 ... Photocurable liquid composition, 22 ... Gas-liquid interface, 24 ... 1st hardening layer, 26 ... 2nd hardening layer, DESCRIPTION OF SYMBOLS 30 ... Dental pulp cavity part, 32 ... Medullary part, 34 ... Root canal, 36 ... Apical hole, 40 ... Crown part, 50 ... Root part, 60 ... Fixing member, 70 ... Container, 100 ... Manufacturing apparatus, 200/202 204: tooth model

Claims (7)

(A) a step of selectively irradiating the photocurable liquid composition with light to form a first cured layer constituting one section of the tooth model;
(B) Applying the photocurable liquid composition to one surface of the first hardened layer, and selectively irradiating the surface with a tooth model on one surface of the first hardened layer. Forming a second hardened layer constituting one cross section;
Including
A method of manufacturing a tooth model, wherein a tooth model having a dental pulp cavity is formed by repeating the step (b). In claim 1,
(C) A method for producing a tooth model, further comprising the step of removing the photocurable liquid composition remaining in the second hardened layer.   A dental model in which a pulpal cavity portion is formed by the method for producing a dental model according to claim 1 or 2. In claim 3,
A tooth model in which the root canal diameter in the pulp cavity is 0.1 mm or more and 50 mm or less. In claim 3 or claim 4,
A tooth model in which the apical hole diameter in the pulp cavity is 0.1 mm or more and 50 mm or less. In any one of Claims 3 thru | or 5,
A tooth model in which a portion of 0.5 mm to 3 mm is curved from the apical hole in the pulp cavity. In any one of Claims 3 thru | or 6,
A dental model in which the pulp cavity has a branched structure.

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