Technical work model

Abstract

To provide a work model which is used for dimension adjustment and aesthetic property application of a dental technical material processed by a CAD / CAM method from oral cavity scan data, and to provide a work model which has similar molding accuracy and is lower in cost compared to a work model molded by a photo fabrication method.SOLUTION: A denture mold model is molded of a photo-setting resin by a photo fabrication method, and a dentition model comprising a socket to which the denture mold model is incorporated, is molded of a thermoplastic resin by a thermal dissolution lamination method.SELECTED DRAWING: Figure 12

Description

Technical Field

[0001] The present invention relates to dental prosthetics. More specifically, it relates to a working model used for adjusting dental prosthetic workpieces processed by CAD / CAM methods in the dental field or imparting aesthetics.

Background Art

[0002] In dental treatment, dentists take impressions of the shape of a patient's oral cavity, and a working model is produced by injecting a molding material such as plaster into the obtained impression for use in the production of dental prosthetic workpieces. Then, dental prosthetic workpieces that harmonize with the patient's unique shape and color tone are produced on this working model.

[0003] In recent years, intraoral scanners and CAD / CAM technologies have been spreading in the dental field, and some dental prosthetic workpieces can be manufactured using a full digital workflow. That is, the process from impression taking to working model production as described above has been digitized, enabling some dental prosthetic workpieces to be manufactured using industrial methods. However, there are problems in the full digital workflow, such as errors and variations from the actual object occurring in each process, which requires dimensional adjustment of the processed dental prosthetic workpiece in the oral cavity. Also, in order to harmonize the shape and color tone of the dental prosthetic workpiece with the patient's oral cavity, it is necessary to cut back the area where the dental prosthetic workpiece is visible to the human eye and manually use a crown restoration material to harmonize the shape and color tone with the patient's oral cavity. However, in the full digital workflow, there is no working model, so there is a problem that it cannot be shaped manually using a crown restoration material.

[0004] To address the above problems, working models are fabricated by stereolithography to adjust the dimensions of processed dental prosthetic workpieces or to harmonize the patient's unique shape and color tone using a crown restoration material. However, although the working model by stereolithography has high detail reproducibility, there are problems such as warping and dimensional changes due to polymerization shrinkage caused by post-curing, as well as high material costs.

[0005] On the other hand, there is an additive manufacturing method using thermoplastic resins via fused deposition modeling (FDM). Although this method has low detail reproduction capabilities and cannot reproduce shapes smaller than the diameter of the printing nozzle, it is characterized by the fact that warping and dimensional changes do not occur at room temperature after fabrication, and the material cost is significantly lower compared to photocurable resins used in stereolithography. In recent years, technological advancements such as improvements in 3D printer performance and slicer software have brought the fabrication accuracy of this additive manufacturing method closer to that of stereolithography.

[0006] Patent Document 1 discloses a method for manufacturing dental crowns, in which a working model is fabricated using a 3D printer employing fused deposition modeling (FDM) with thermoplastic and water-soluble PVA resin, a dental crown is molded onto the working model, and the molded dental crown is removed by dissolving the model in water. When a working model including the tooth shape of the abutment tooth is fabricated using FDM, as mentioned above, the reproduction of fine details is poor, resulting in the disadvantage that the margin lines and corner edge shapes of the abutment tooth are not reproduced. This disadvantage can negatively affect the required quality of dental prosthetics, such as the fit of the margin of the dental crown to the abutment tooth and the cement space. In addition, while the method in Patent Document 1 can manufacture resin-based dental crowns, it has the disadvantage of not being able to manufacture ceramic-based dental crowns, which require the process of building up porcelain on the abutment tooth, releasing it from the working model, and firing it. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2019-195584 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The present invention aims to provide a working model for adjusting dental prosthetics processed by CAD / CAM from intraoral scan data. Specifically, it aims to provide a working model for dental prosthetics used for dimensional adjustment and aesthetic enhancement of dental prosthetics processed by CAD / CAM based on intraoral scan data, which is superior in molding accuracy, long-term dimensional stability, and cost. Furthermore, it is characterized by comparable molding accuracy, long-term dimensional stability, and cost-effectiveness compared to working models made of stereolithography. [Means for solving the problem]

[0009] Therefore, the present invention aims to provide a resin working model to improve the dimensional adjustment of dental prosthetics processed by CAD / CAM methods in the dental field and to enhance the aesthetics of dental prosthetics using crown restoration materials. In this invention, dental prosthetics include dental prosthetics such as crowns, bridges, inlays, and implants, as well as orthodontic appliances such as plates and wires, bracket positioning jigs (indirect bonding cores), and retention devices such as retainers, splints, and mouthpieces. The present invention relates to a dental laboratory model used for arranging and adjusting dental prosthetics fabricated by a CAD / CAM device based on a patient's intraoral scan data, and is characterized by being made of resin. Furthermore, the present invention is a method for manufacturing a dental laboratory model used to arrange a dental prosthesis fabricated by a CAD / CAM device based on intraoral scan data of a patient, and to adjust the dental prosthesis, and is characterized by comprising the steps of: acquiring three-dimensional shape data of the dentition using an intraoral scanner; creating shape data for a dental laboratory model based on the three-dimensional shape data; creating molding data from the shape data of the dental laboratory model; and manufacturing the dental laboratory model using one or more methods of stereolithography or fused deposition modeling based on the molding data. [Effects of the Invention]

[0010] The present invention provides a working model made of resin, which is used in the manufacturing of dental prosthetics when plaster models are unavailable, for purposes such as adjusting the dimensions and enhancing the aesthetics of dental prosthetics. The objective is to provide a working model that excels in molding accuracy, long-term dimensional stability, and cost. Furthermore, it is characterized by having comparable molding accuracy, long-term dimensional stability, and cost-effectiveness compared to working models made using stereolithography. [Brief explanation of the drawing]

[0011] [Figure 1] A cylinder created using stereolithography. [Figure 2] A cylinder fabricated by fused deposition modeling (FDM). [Figure 3] Measurement area of ​​the cylinder [Figure 4] Simplified mandibular dentition model fabricated using stereolithography. [Figure 5] Simplified mandibular dentition model fabricated using fused deposition modeling (FDM). [Figure 6] Dimensional measurement sites in a simplified mandibular dentition model [Figure 7] Measurement site of curvature in a simplified mandibular dentition model [Figure 8] Designed dental model in the example [Figure 9] Designed dental model in the example [Figure 10] Tooth model in the example [Figure 11] Dental model in the example [Figure 12] Completed dental laboratory model in the example [Figure 13] Image showing a zirconia coping bridge attached to a working model made of ultra-hard gypsum. [Figure 14] Image showing a zirconia coping bridge attached to a working model of a stereolithography object. [Figure 15] Image showing a working model of a fused deposition modeling (FDM) object with a zirconia coping bridge attached. [Figure 16]An image of a working model combining a photoformed object and an object formed by the fused deposition modeling method, with a zirconia coping bridge attached [Figure 17] An enlarged image of No. 43 in the working model of super hard plaster [Figure 18] An enlarged image of No. 45 in the working model of super hard plaster [Figure 19] An enlarged image of No. 47 in the working model of super hard plaster [Figure 20] An enlarged image of No. 43 in the working model of the photoformed object [Figure 21] An enlarged image of No. 45 in the working model of the photoformed object [Figure 22] An enlarged image of No. 47 in the working model of the photoformed object [Figure 23] An enlarged image of No. 43 in the working model of the object formed by the fused deposition modeling method [Figure 24] An enlarged image of No. 45 in the working model of the object formed by the fused deposition modeling method [Figure 25] An enlarged image of No. 47 in the working model of the object formed by the fused deposition modeling method [Figure 26] An enlarged image of No. 43 in the working model combining a photoformed object and an object formed by the fused deposition modeling method [Figure 27] An enlarged image of No. 45 in the working model combining a photoformed object and an object formed by the fused deposition modeling method [Figure 28] An enlarged image of No. 47 in the working model combining a photoformed object and an object formed by the fused deposition modeling method [Figure 29] A modeling model for confirming the detailed reproducibility in the examples

Mode for Carrying Out the Invention

[0012] The working model of the present invention is a resin working model manufactured using three-dimensional shape data from intraoral scan data and 3D printing technology. More specifically, it is a dental laboratory working model used to position and adjust dental prostheses fabricated by a CAD / CAM device based on intraoral scan data of a patient, and comprises a dentition model and a tooth model, wherein the dentition model has a dentition portion and a base portion, the dental prosthesis is positioned on the tooth model, the dentition model is a fused deposition modeling product of thermoplastic resin, and the tooth model is a stereolithography product of photocurable resin. When performing dental laboratory work, the dental prosthesis can be adjusted while checking the overall shape of the dentition model. Furthermore, if a plaster model is not available using an intraoral scanner, the working model of the present invention can be used as a delivery model, and the fabricated prosthesis and the working model can be delivered as a set.

[0013] The dental laboratory model in this invention is shaped to resemble the inside of a patient's mouth. The tooth model is primarily the area on which dental prosthetics are placed. When the working model of this invention is used to adjust dental prosthetic devices, it is intended to represent abutment teeth, cavity-prepared teeth, or tooth crown shapes. When used to adjust orthodontic materials or retainers, it is intended to represent tooth crown shapes, etc., that the orthodontic materials or retainers make contact with.

[0014] The configuration for combining the dental arch model and the dental impression model is arbitrary. The dental impression model can be fitted into the dental arch model, bonded with adhesive, or simply placed on top of the dental arch model. However, it is preferable to provide the dental arch model with a socket for mounting the dental impression model, as this allows for confirmation of the fit of each tooth to the model of the fabricated prosthesis. Furthermore, when providing a socket for mounting the dental impression model, the shape of the socket is arbitrary, but a polygonal shape such as a rectangle is preferable to prevent errors in the position of the dental impression model.

[0015] The thermoplastic resin used in fused deposition modeling in the present invention is preferably selected from polylactic acid, ABS resin, PET resin, PETG resin, polycarbonate resin, polyamide resin, polypropylene resin, polyethylene resin, ASA resin, and TPU resin. Polylactic acid is particularly preferred due to its cost-effectiveness, low warping of the molded object, high accuracy, and ease of molding.

[0016] In the working model of the present invention, when adjusting a dental prosthesis, the dental prosthesis is placed on the tooth model. The tooth model may be in the shape of multiple teeth or a single tooth, but it is preferable to have the shape of a single tooth from the viewpoint of polymerization shrinkage rate of the stereolithographic product.

[0017] The resin working model of the present invention is a working model comprising a dental arch model and a tooth model. Preferably, the dental arch model has a socket into which the tooth model is incorporated. The tooth model refers to the abutment teeth, cavity-preparing teeth, or crowns within the dental arch model. The socket refers to a hole into which the tooth model is incorporated. The resin working model may be a tooth model fixed type model, a divisible and repositionable type model, a tooth model removable type model, or a secondary tooth model type model.

[0018] The photocurable resin used in the working model of the present invention may contain a mixture of fillers, dyes, pigments, etc.

[0019] The thermosetting resin used in the working model of the present invention is preferably one of the following: polylactic acid, ABS resin, PET resin, PETG resin, polycarbonate resin, polyamide resin, polypropylene resin, polyethylene resin, ASA resin, or TPU resin. However, a thermoplastic resin that can be molded into pellet or filament shapes may also be used. Furthermore, the thermoplastic resin may be mixed with fillers, dyes, pigments, cellulose nanofibers, etc.

[0020] The working model of the present invention is manufactured by the following steps: acquiring three-dimensional intraoral shape data using an intraoral scanner; creating working model data from the three-dimensional intraoral shape data; creating modeling data from the working model data; and fabricating the working model from the modeling data. The step of creating working model data from three-dimensional intraoral shape data is performed using 3D CAD. The step of creating modeling data from working model data is performed using slicer software. The step of fabricating the working model from the modeling data preferably involves a combination of stereolithography and fused deposition modeling. The 3D printer used for fabrication may be of the SLA, DLP, LCD, FDM, FFF, or MEX type. [Examples]

[0021] (Comparison of detail reproduction capabilities in stereolithography and fused deposition modeling) To evaluate the detail reproduction capabilities under different manufacturing methods, shape data of cubes with different dimensions, as shown in Figure 29, was created. The dimensions of the cubes were 0.10 mm, 0.20 mm, 0.30 mm, 0.40 mm, 0.50 mm, and 1.00 mm. Manufacturing data was created from the shape data of these cubes, and the objects were fabricated using stereolithography and fused deposition modeling. The fabrication results are shown in Table 1. Objects that were successfully fabricated are marked with ○, and objects that were not fabricated are marked with ×. Here, "successful fabrication" refers to the state where the shape data can be molded onto the platform by the 3D printer and the shape can be visually confirmed. Conversely, "unsuccessful fabrication" refers to the state where the shape data cannot be molded onto the platform by the 3D printer and the shape cannot be visually confirmed. Stereolithography was able to fabricate cubes down to 0.20 mm, while fused deposition modeling (FDM) could only fabricate cubes down to 0.40 mm. From these experimental results, it can be said that stereolithography has higher detail reproduction capabilities than FDM.

[0022] [Table 1]

[0023] (Cylindrical shape) A cylinder with a diameter of 20 mm and a height of 20 mm was designed using general-purpose 3D CAD software (Rhinoceros 3D, Robert McNeel & Associates, USA), and STL data of the cylindrical shape was output. Then, using the cylinder STL data, slicing software was used to create data for printing, and the cylinders were printed using a DLP 3D printer (CarlaPrint 4.0, Kulzer) loaded with photocurable resin (Diema Printstone, Kulzer, Germany) and a fused deposition modeling (FDM) 3D printer loaded with PLA filament (PolyLitePLA, Polymaker, China). The stereolithography samples were washed with ethanol and post-cured. Figure 1 shows the cylinder printed by stereolithography. Figure 2 shows the cylinder printed by FDM.

[0024] (Comparison of dimensional changes and dimensional errors for each cylindrical object) The dimensions of the two types of fabricated samples were measured using a digital caliper (ABSOLUTE AOS DIGIMATIC, Mitutoyo, Japan) at the following timings: immediately after fabrication, after post-curing, one day after fabrication, and two days after fabrication. The dimensional change and the dimensional error from the design value were then calculated. Figure 3 shows the measurement points for the cylinders. Table 2 shows the dimensional change of the cylindrical sample fabricated with a DLP 3D printer. Table 3 shows the dimensional change of the cylindrical sample fabricated by fused deposition modeling (FDM). Table 4 shows the dimensional error of the cylindrical sample fabricated with a DLP 3D printer. Table 5 shows the dimensional error of the cylindrical sample fabricated by fused deposition modeling (FDM). It was confirmed that the dimensions of objects fabricated with a DLP 3D printer change up to one day after fabrication. Furthermore, it was confirmed that the dimensional error after dimensional stabilization was -0.06 mm in the XY direction and -0.15 mm in the Z direction. It was confirmed that objects fabricated using fused deposition modeling (FDM) 3D printers exhibit no dimensional changes at room temperature and have a dimensional error of 0.00 mm. For this shape, FDM was found to have better dimensional stability and accuracy than stereolithography (SLA).

[0025] [Table 2]

[0026] [Table 3]

[0027] [Table 4]

[0028] [Table 5]

[0029] (Shaping a simplified model of the mandibular dentition) A simplified mandibular dentition model was designed using general-purpose 3D CAD software (Rhinoceros 3D), and STL data was output. Then, the STL data of the simplified mandibular dentition model was used with slicer software to create 3D modeling data, and the models were printed using a DLP 3D printer (Carlaprint 4.0, Kulzer) loaded with photocurable resin (Diema Printstone, Kulzer, Germany) and a fused deposition modeling (FDM) 3D printer loaded with PLA filament (PolyLite PLA, Polymaker, China). The stereolithography samples were washed with ethanol and post-cured. The simplified mandibular dentition model printed by stereolithography is shown in Figure 4. The simplified mandibular dentition model printed by FDM is shown in Figure 5.

[0030] (Comparison of dimensional changes and dimensional errors of each simplified mandibular dentition model) The dimensions of the two types of fabricated samples were measured using a digital caliper (ABSOLUTE AOS DIGIMATIC, Mitutoyo, Japan) at the following timings: immediately after fabrication, after post-curing, one day after fabrication, and two days after fabrication. The dimensional change and the dimensional error from the design value (measurement site A 67.00 mm, measurement site B 50.98 mm) were then calculated. Figure 6 shows the measurement sites for the dimensional changes of the simplified mandibular dentition model. Table 6 shows the dimensional change of the simplified mandibular dentition model sample fabricated with a DLP 3D printer. Table 7 shows the dimensional change of the simplified mandibular dentition model sample fabricated with Fused Deposition Modeling (FDM). Table 8 shows the dimensional error of the simplified mandibular dentition model sample fabricated with a DLP 3D printer. Table 9 shows the dimensional error of the simplified mandibular dentition model sample fabricated with FDM. Objects printed using a DLP 3D printer were found to undergo dimensional changes up to one day after printing. Furthermore, the dimensional errors after dimensional stabilization were confirmed to be -0.14 mm at measurement point A and -0.08 mm at measurement point B. Objects printed using a fused deposition modeling (FDM) 3D printer showed no dimensional changes at room temperature, and the dimensional errors were confirmed to be -0.05 mm at measurement point A and 0.07 mm at measurement point B. In this shape as well, FDM was found to have better dimensional stability and accuracy than stereolithography.

[0031] [Table 6]

[0032] [Table 7]

[0033] [Table 8]

[0034] [Table 9]

[0035] (Comparison of the two-dimensional curvature of each simplified mandibular dentition model) The amount of warpage of the two types of fabricated samples was measured using a digital caliper (ABSOLUTE AOS DIGIMATIC, Mitutoyo) at the time immediately after fabrication, after post-curing, one day after fabrication, and two days after fabrication. The measurement site and method for two-dimensional warpage are shown in Figure 15. Specifically, a load of 500g was applied to the blocks corresponding to the bilateral molar areas of the simplified mandibular dentition model, and the measurement site shown in Figure 7 was measured using a digital caliper (ABSOLUTE AOS DIGIMATIC, Mitutoyo). Table 10 shows the amount of warpage of the simplified mandibular dentition model sample fabricated with a DLP 3D printer. Table 11 shows the amount of warpage of the simplified mandibular dentition model sample fabricated by fused deposition modeling. It was confirmed that the amount of warpage of the fabricated object using a DLP 3D printer increased until one day after fabrication. Furthermore, it was confirmed that the amount of warpage after dimensional stabilization was 0.15 mm. It was confirmed that objects fabricated using fused deposition modeling (FDM) 3D printers exhibit no dimensional changes at room temperature and have a warp of 0.03 mm. For this shape, it was confirmed that FDM resulted in less warping than stereolithography (SLA).

[0036] [Table 10]

[0037] [Table 11]

[0038] (Design of a removable dental model) A dental dentition model made of ultrahard gypsum was scanned using a dental laboratory desktop scanner (D2000, 3Shape, Denmark). The mandible had teeth 43, 45, and 47 prepared as abutment teeth for crowns, while teeth 44 and 46 were missing. The obtained three-dimensional shape data was then used to design a removable dental model using dental 3D CAD software (Dental Designer 2020, 3Shape). In this design, the crown abutment teeth were used as the dental model. The design data was output as an STL file. A perspective view of the designed dental model is shown in Figure 8. A perspective view of the dental model with a socket into which the designed dental model is incorporated is shown in Figure 9.

[0039] (Shaping of dental models in removable dental models) Using the STL data of the aforementioned dental model, 3D printing data was created using slicer software, and the model was printed using a DLP 3D printer (Carlaprint 4.0, Kulzer) equipped with a photocurable resin (Diema Printstone, Kulzer, Germany). The photocured sample was cleaned with ethanol and post-cured. The completed dental model is shown in Figure 10.

[0040] (Shaping of a dental arch model having a socket into which a dental model is incorporated in a removable dental model) Using STL data of a dental model with a socket into which a dental impression model is incorporated, 3D printing data was created using slicer software, and the model was printed using a fused deposition modeling (FDM) 3D printer loaded with PLA filament (PolyLitePLA, Polymaker, China). The completed dental model with a socket into which a dental impression model is incorporated is shown in Figure 11.

[0041] (Fabrication of removable dental models) A removable tooth model was completed by incorporating a tooth model fabricated using stereolithography into a socket in a dental model that has a socket into which the tooth model is incorporated. The completed removable tooth model is shown in Figure 12. Stereolithography was used for the abutment tooth shape, which requires detailed reproduction. Furthermore, fused deposition modeling (FDM) was used for the dental model with a socket into which the tooth model is incorporated, from the perspective of dimensional stability, small dimensional errors, small deformation due to warping, and material cost. This combination is expected to enable the manufacture of a working model with high shape reproduction accuracy relative to the design data, and to provide a working model with lower material costs compared to a working model made using only stereolithography.

[0042] (Comparative observation of the fit of zirconia coping bridges to working models obtained by each manufacturing method, and quantitative evaluation of margin gap size) A dental laboratory desktop scanner (D2000, 3Shape, Denmark) was used to scan a dentition model made of ultra-hard gypsum, in which teeth 43, 45, and 47 of the mandible had been prepared as abutment teeth for crowns, and teeth 44 and 46 were missing. The resulting three-dimensional shape data was then used to design a coping bridge using dental 3D CAD software (Dental Designer 2020, 3Shape). The STL data of the coping bridge was output, and fabrication data was created using CAM software (GO2dental ver.6.04, GO2cam International, France). Then, a dental milling machine (DWX-51D, DG Shape, Japan) was loaded with dental cutting ceramics (Shofu Disc ZR Lucent Supra, Shofu, Japan) and three dental milling burs (Shofu CAD / CAM milling burs BE-2.0-4-DLC, BE-1.0-4-DLC, BE-0.6-4-DLC, Shofu), and cutting was performed using the corresponding processing data. After connector cutting, the resulting processed parts were sintered in a zirconia sintering furnace (Ostromat 664i, DEKEMA, Germany). The sintered processed parts were then given an additional surface treatment by alumina sandblasting. Next, using the same method as described above, fixed tooth models were fabricated using stereolithography, fixed tooth models using fused deposition modeling, and removable tooth models combining stereolithography and fused deposition modeling. The zirconia coping bridge was then fitted to a dental model made of ultra-hard gypsum, a model created by stereolithography, a model created by fused deposition modeling (FDM), and a removable dental model created by combining stereolithography and FDM, and the fit was observed. Figure 13 shows an image of the zirconia coping bridge fitted to a dental model made of ultra-hard gypsum. Figure 14 shows an image of the zirconia coping bridge fitted to a model created by stereolithography. Figure 15 shows an image of the zirconia coping bridge fitted to a model created by FDM. Figure 16 shows an image of the zirconia coping bridge fitted to a removable dental model created by combining stereolithography and FDM. The fit of the zirconia coping bridge to the dental model made of ultra-hard gypsum, the model created by stereolithography, and the removable dental model created by combining stereolithography and FDM was confirmed to be good, with minimal gaps at the margins of the abutment teeth.The fit of the zirconia coping bridge to the fabricated object using fused deposition modeling was poor, with many gaps at the abutment tooth margins.

[0043] In addition, with the zirconia coping bridges attached to the working models obtained by each manufacturing method, a digital microscope (Dino capture 2.0, Ammo Co., Ltd., Taiwan) was used to photograph the margin gaps between the zirconia coping bridges and the abutment teeth, the mandibular right canine (hereinafter referred to as tooth 43), mandibular right second premolar (hereinafter referred to as tooth 45), and mandibular right second molar (hereinafter referred to as tooth 47), at 40x magnification. Figure 17 shows a magnified image of tooth 43 in the dentition model made of ultrahard gypsum. Figure 18 shows a magnified image of tooth 45 in the dentition model made of ultrahard gypsum. Figure 19 shows a magnified image of tooth 47 in the dentition model made of ultrahard gypsum. Figure 20 shows a magnified image of tooth 43 in the object fabricated by stereolithography. Figure 21 shows a magnified image of tooth 45 in the object fabricated by stereolithography. Figure 22 shows a magnified image of tooth 47 in the object fabricated by stereolithography. Figure 23 shows a magnified image of tooth 43 in the object fabricated by fused deposition modeling. Figure 24 shows a magnified image of object 45 fabricated by fused deposition modeling (FDM). Figure 25 shows a magnified image of object 47 fabricated by FDM. Figure 26 shows a magnified image of object 43 fabricated using a combination of stereolithography and FDM for removable tooth profiles. Figure 27 shows a magnified image of object 45 fabricated using a combination of stereolithography and FDM for removable tooth profiles. Figure 28 shows a magnified image of object 47 fabricated using a combination of stereolithography and FDM for removable tooth profiles. The margin gap amount in these magnified images was then measured. The margin gap was calculated by annotating two points on the magnified image: the margin of the coping bridge and the abutment tooth margin, and then calculating the distance between these two points. The measurement results for the margin gap are shown in Table 12. From Table 12, it was confirmed that the margin gaps of the objects fabricated by stereolithography and the removable tooth model combining stereolithography and fused deposition modeling were equivalent to those of the standard tooth model made of ultrahard gypsum. The objects fabricated by fused deposition modeling were found to have a margin gap approximately 2.00 times larger than that of the standard tooth model made of ultrahard gypsum. As a general guideline for margin gap size, in practice, 120.00 μm or less is preferable, and if it is 120 μm or more, it may be problematic as it increases the risk of inducing secondary caries in practical use. In this experiment, since the tooth model made of ultrahard gypsum was the object measured for acquiring shape data, the comparative evaluation was performed using this tooth model as the standard.

[0044] [Table 12]

[0045] These results suggest that the removable dental model fabricated using a combination of stereolithography and fused deposition modeling (FDM) possesses a shape equivalent to that of the master model, a dentition model made of ultra-hard gypsum. Therefore, both the stereolithography fabricated product and the removable dental model fabricated using a combination of stereolithography and FDM are considered to be of sufficient quality for use in adjusting the dimensions of dental prosthetics processed by CAD / CAM and for enhancing aesthetics by shaping them with crown restoration materials. Furthermore, since the removable dental model fabricated using a combination of stereolithography and FDM is composed entirely of thermoplastic resin except for the abutment teeth, it is considered that significant material cost reductions are possible compared to stereolithography alone. Based on the above, the present invention possesses the dimensional accuracy necessary for adjusting the dimensions and enhancing the aesthetics of dental prosthetics, and significantly reduces material costs compared to stereolithography alone, making it useful in dental clinical practice. [Industrial applicability]

[0046] The working model according to the invention can be used for dimensional adjustment and aesthetic improvement of dental prosthetics processed by CAD / CAM methods, and is useful for improving the quality and uniformity of dental prosthetics in the dental field. [Explanation of symbols]

[0047] 1. Dental model 2. Dental model 3. Dental arch 4. Base 5 sockets

Claims

[Claim 1] Based on the patient's intraoral scan data, dental prosthetics fabricated using a CAD / CAM system are placed. A method for manufacturing a dental laboratory model used for adjusting the aforementioned dental prosthesis, The process involves acquiring three-dimensional shape data of the dentition using an intraoral scanner, A step of creating shape data for a dental work model based on the three-dimensional shape data, The process of creating shaping data for a dental arch model having a tooth arch portion and a base portion, and having a socket for attaching a dental model to the base portion, from the shape data of the aforementioned dental laboratory work model, A step of creating shaping data for a dental model on which the dental prosthesis is placed, from the shape data of the aforementioned dental work model, Based on the fabrication data of the aforementioned dental arch model, a step is made to fabricate a dental arch model by fused deposition modeling using a thermoplastic resin selected from polylactic acid, ABS resin, PET resin, PETG resin, polycarbonate resin, polyamide resin, polypropylene resin, polyethylene resin, ASA resin, and TPU resin. A step of fabricating a tooth model using photopolymerization with a photocurable resin based on the molding data of the aforementioned tooth model, The process of attaching a dental model made by stereolithography to a socket made by fused deposition modeling, A method for manufacturing a dental laboratory model, characterized by including [the necessary components].

Images