JP2022132783A - Heat-softening denture base prototype - Google Patents

Abstract

To provide: a denture base prototype which can accurately reproduce an inside of the oral cavity of a patient in denture production by a resin polymerization method, and allows production without a need for skillful techniques; and a method in a process of denture production which is excellent in operativity and safety and allows quick and inexpensive production.SOLUTION: A denture base prototype for use in denture production by a resin polymerization method includes an artificial tooth socket, and comprises a thermoplastic resin having a softening point of 30°C-90°C.SELECTED DRAWING: Figure 1

Description

The present invention relates to dental prostheses. More particularly, it relates to a denture base prototype used for resin polymerization in the dental field.

In general, denture production by resin polymerization involves taking an impression from a patient, producing a plaster model based on the impression, and producing waxy dentures (denture base model) on the model. The prepared waxy denture (denture base prototype) is embedded in gypsum in a dental flask, and after hardening, the wax is heated to dissolve and remove the waxy portion. The resin is put into the denture negative mold in the flask, the resin is polymerized by heating, the denture after polymerization is indexed from the gypsum, and the denture is finished by polishing. Denture fabrication by the resin polymerization method has been used for a long time, and it is possible to use materials for denture bases with extensive clinical experience. One of the advantages is that it is high.

As described above, the denture base prototype in conventional denture fabrication by the resin polymerization method is generally made from wax. There are problems such as the possibility that quality may vary depending on the skill of the person, and the time and labor required for production. In addition, there are safety issues in the process of melting and removing the wax by heating, the post-treatment of the melted wax is troublesome, and residual wax reduces the adhesiveness between the artificial tooth and the resin. There were problems such as fear.

In Cited Documents 1 to 3, an attempt is made to prepare a denture base model using a water-soluble wax, which is different from the prior art. By using a water-soluble wax, the safety of the process of melting and removing the wax by heating is improved, the post-treatment of the melted wax is easy, which is preferable from an environmental point of view, and the adhesion of the wax to the artificial teeth is reduced. Benefits such as the elimination of concerns are considered. However, the water-soluble wax is not suitable for work because it is not easy to operate, and when it is tried on in the oral cavity, the water-soluble wax melts with saliva. There is In addition, regardless of the type, the production of a denture base model from wax requires skilled skills as described above, requires time and labor for production, and may result in a difference in quality.

Shinnao Ando et al., "Proposal for Ecological Laboratory Work Using Water-Soluble Wax", Dental Technician, Ishiyaku Publishing Co., Ltd., 2010, vol.38, no.2, p235-242 Shinnao Ando et al., "Proposal for ecological laboratory work using water-soluble wax", Dental Laboratory, Ishiyaku Publishing Co., Ltd., 2010, vol.38, no.4, p478-483 Shinnao Ando et al., "Proposal for ecological laboratory work using water-soluble wax", Dental Laboratory, Ishiyaku Publishing Co., Ltd., 2010, vol.38, no.6, p713-719

An object of the present invention is to provide a denture base model that can accurately reproduce the inside of a patient's oral cavity and that can be produced without the need for skilled skills in the production of dentures by the resin polymerization method. . Another object of the present invention is to provide a method of manufacturing dentures which is excellent in operability and safety and which can be manufactured in a short time and at a low cost.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a thermoplastic resin denture base model having an artificial tooth socket so that dentures can be manufactured by the resin casting method in the dental field.
The denture base master of the present invention is a denture base master used in the manufacture of dentures by resin polymerization, is equipped with an artificial tooth socket, and is characterized by being made of a thermoplastic resin having a softening point of 30°C to 90°C.
Further, the present invention is a method for producing a denture base model used for producing dentures by resin polymerization, and is characterized in that it is produced using a 3D printer based on a fused lamination method.
In addition, the present invention provides a method for producing a denture base by a resin polymerization method, in which a thermoplastic resin denture base model at 30° C. to 90° C. is used as a denture base model, and artificial teeth are fixed to the denture base model. embedding the denture base model with the artificial teeth fixed in gypsum; removing the denture base model by softening the denture base model by heating; filling resin into the denture negative mold and polymerizing the resin. A manufacturing method characterized by comprising:

The denture base prototype of the present invention can be easily removed from the gypsum mold by softening by heating, compared with the conventional denture base prototype made of wax, and is excellent in operability and safety in denture production work, and can be produced in a short time. characterized by being able to In addition, since no wax remains on the artificial tooth compared to a conventional denture base model made of wax, there is no risk of lowering the adhesive strength between the denture base and the artificial tooth due to residual wax.

The denture base model of the present invention is produced using a 3D printer based on the hot-melt lamination method. However, the same quality can be produced. In addition, since the scanned intraoral data of the patient can be used, the intraoral cavity of the patient can be accurately reproduced. In addition, since the method for producing a denture base model of the present invention uses a resin polymerization method to produce dentures, it is possible to produce dentures using denture base materials with extensive clinical experience, at a low cost, and in a short period of time. can be done.

Cross-sectional view of a denture base prototype according to an example Prototype of denture base after modeling with a 3D printer (before removing support material) Prototype of denture base after softening removal in the example Denture base replaced with heat-polymerized resin in Example

The denture base model of the present invention has an artificial tooth socket. The term "artificial tooth socket" refers to a portion where an artificial tooth is attached to the manufactured denture base model. The shape of the artificial tooth socket may be a position that reproduces a standard dentition or a position that reproduces a patient-specific dentition.
When attaching the artificial tooth to the artificial tooth socket of the denture base, it may be attached without using anything, or wax or the like may be used as an adhesive.

The resin used for the denture base mold of the present invention is a thermoplastic resin having a softening point of 30°C to 90°C.
A thermoplastic resin with a softening point of 30° C. to 90° C. can be used as the denture base prototype of the present invention without any problems, but it has poor removability, operability, ease of detachment in the case of an undercut shape, and work safety. From the viewpoint of, the softening point is preferably 40°C to 70°C. In particular, thermoplastic resins having a softening point of 50° C. to 60° C. are most preferably used.
Here, the softening point is the point at which the fluidity of an amorphous solid such as glass or plastic increases sharply when the temperature is increased and the temperature passes through a relatively narrow temperature range. The measurement method is ASTM D1525 (ISO 306 GB/T 1633) test method. Increase the temperature of the bath. Then, the temperature is recorded when the end face of the test piece bites to a depth of 1.0 mm.

The resin that can be used as the denture base model of the present invention is not particularly limited as long as it is a thermoplastic resin having a softening point of 30°C to 90°C. Polylactic acid resin, PET resin, and PVA resin are preferable, and polylactic acid resin is most preferably used, from the viewpoints of work safety in the heating process, molding accuracy during prototyping, and the like.

The denture base model of the present invention can be produced by any method such as production using a 3D printer, cutting using CADCAM technology, injection molding, or the like. Among them, it is preferable to use a 3D printer.
In particular, it is most preferable to use a 3D printer based on the hot-melt lamination method. In the case of using the above method, the accuracy of the denture base prototype is not affected by the skill of the operator, the patient's oral cavity can be reproduced with high accuracy, and the density (infill) of the internal structure of the denture base prototype can be freely adjusted. It is possible to obtain merits such as being able to design, being able to produce a denture base prototype in a short time, being excellent in terms of cost, and being able to reproduce the undercut shape.

The internal structure of the denture base model of the present invention can also be arbitrarily produced, but the ease of softening of the denture base model by heating, the ease of removal, the time required to produce the denture base model, the cost of raw materials, etc. Considering that, it is preferable to have cavities in the internal structure.
Regarding the internal structure, for example, if it is a 3D printer, it can be easily adjusted by appropriately setting the density (infill density). Preferably the density (infill density) is 5-40%, most preferably 20-30%. The above density (infill density) can be most preferably used from the viewpoints of difficulty in deformation of the denture base master, molding time, ease of removal, ease of detachment in the case of an undercut shape, and the like. .

The denture base mold of the present invention can be softened by heating by any method such as heating with hot water, heating with a microwave oven, or dry heating with an oven.

<Example of full denture production>
Three-dimensional measurement of the working model is performed with a desktop scanner for laboratory work (E3, 3Shape, Denmark) in a state in which the working model is completed up to the process of attaching the articulator. Next, the three-dimensional shape data of the three-dimensionally measured model is imported into dental CAD software (Dental Designer 2020 Full Dentures, 3Shape, Denmark) to design a complete denture. When designing a complete denture, the patient-specific artificial tooth arrangement is desirable for the virtual artificial tooth arrangement.

After designing the complete denture, output the STL data of the denture base with the artificial tooth socket. The output STL data is imported into slicer software (SIMPLIFY3D, Simplify3D, USA) to create modeling data. The modeling conditions for creating modeling data were as follows: polylactic acid was selected as the material, the modeled object was placed horizontally with respect to the Z axis, automatic support was set, the diameter of the nozzle was 0.4 mm, and the layer pitch was 0.4 mm. 050 mm to 0.300 mm, preferably 0.100 mm, extruder temperature of 190° C., bed temperature of 60° C., and infill of 5% to 100%, preferably 20%. Note that the infill is a parameter that controls the density of the modeled object. After creating the modeling data, import the modeling data into a 3D printer (Moth Mach S3DP224, S Lab, Kyoto, Japan) and perform 3D printing with polylactic acid filament (PolyLite PLA, Polymaker, China). . The thermoplastic resin filament used for 3D printing is preferably polylactic acid, but if it has a glass transition temperature in the range of 30° C. to 90° C. such as PET, the denture base model can be formed. Next, the support attached to the modeled object (denture base prototype) obtained by 3D printing is removed by hand. Then, a ready-made artificial tooth (Belasia SA, Shokaze, Kyoto, Japan) is placed in the artificial tooth socket in the denture base model and fixed with wax. At this time, the artificial teeth to be fixed are preferably ready-made artificial teeth, but may be custom-made artificial teeth manufactured by 3D printing or cutting.

The denture base model to which the artificial teeth are fixed is embedded in a dental flask with gypsum. Specifically, a dental flask is coated with a layer of petroleum jelly, and a denture base prototype to which artificial teeth are fixed is fixed to a working model with wax. After the primary burial is completed, a gypsum separating material is applied to the hardened gypsum, the upper portion of the flask is set to the lower portion of the flask, and secondary burial is performed with gypsum. At the time of burial, it is preferable to fix the denture base prototype with the artificial teeth fixed to the working model with wax, and then bury it with gypsum. You can bury yourself. As for the gypsum used for burial, ordinary gypsum is preferable, but hard gypsum or ultra-hard gypsum is used only for the parts that come into contact with the artificial tooth or denture base model for the purpose of improving the surface properties and improving the strength of the negative mold. can be
After the implantation is completed, the embedded dental flask is submerged in hot water for 1 to 5 minutes to divide the embedded dental flask into upper and lower parts. At the same time as the division, the denture base model softened with hot water is removed. Then, a resin separation material (alginate vanish, Shofu) is applied to the gypsum portion of the obtained split-type denture negative mold (completion of the denture negative mold).

After the denture negative mold is completed, the powder (polymer) and the liquid (monomer) of heat polymerization resin for denture base (Urban, Shofu) are mixed. When the mixture of the heat-polymerized resin for denture base changes from sand-like to rice cake-like, the mixture of heat-polymerized resin for denture base is press-filled into the denture negative mold. After filling the denture base heat-polymerized resin mixture into the denture mold, the dental flask was fixed with bolts and screws, and the dental flask was placed in a heat polymerization machine (Aquamarathon, Dentrochemical, Japan, Tokyo). put in and polymerize. In this example, a heat polymerization resin for denture base was used, but a room temperature polymerization resin for denture base (Fitresin, Shofu) may also be used.
After the completion of polymerization of the heat-polymerized denture base resin, stress relaxation is performed for a minimum of 720 minutes. After stress relaxation, the denture is indexed from the denture negative mold using gypsum forceps. After the complete denture is indexed, it is immersed in a gypsum solution (Supermelt, Shofu) for 30 to 120 minutes to chemically remove gypsum adhering to the denture base.
The fabricated denture is remounted on the articulator and occlusal adjustment is performed. Finally, the denture is mirror-polished to complete the complete denture.

<An example of manufacturing a partial denture>
Three-dimensional measurement of the working model is performed with a desktop scanner for laboratory work (E3, 3Shape, Denmark) in a state in which the working model is completed up to the process of attaching the articulator. Next, the three-dimensional shape data of the three-dimensionally measured model is imported into dental CAD software (Dental Designer 2020 Removable Design, 3Shape, Denmark) to design a framework. After designing the framework, combine model data and framework data. The combined data is designed with dental CAD software (Dental Designer 2020 removable design) to design denture base data with artificial tooth sockets, and the designed framework and denture base data are exported.

Next, the designed framework data is imported into slicer software (Caraprint CAM, Kulzer Japan, Japan, Osaka) to create modeling data. The modeling data of the framework is imported into a DLP 3D printer (Carlaprint 4.0, Kulzer Japan) and modeled with a heat-dissipating modeling ink (Dimaprint Cast Ruby, Kulzer Japan). After modeling, the model is washed with isopropanol and post-cured for 5 minutes with a polymerization device for dental laboratory use (Solidylight LED, Shofu). After post-curing, the modeled framework is embedded in a phosphate-based investment material (Snow White 3D, Matsukaze) to harden the investment material. After the investment material has hardened, the hardened investment material is placed in the laboratory furnace and heated. After heating to make a mold, the cobalt-chromium alloy is high-frequency cast with a dental casting machine (Argon Caster i, Shofu). After the cobalt-chromium alloy is cast, it is indexed from the investment material and the framework casting is fitted and polished to complete the framework.

The output STL data of the denture base is imported into slicer software (SIMPLIFY3D) to create modeling data. The modeling conditions for creating modeling data were as follows: polylactic acid was selected as the material, the modeled object was placed horizontally with respect to the Z axis, automatic support was set, the diameter of the nozzle was 0.4 mm, and the layer pitch was 0.4 mm. 050 mm to 0.300 mm, preferably 0.100 mm, extruder temperature of 190° C., bed temperature of 60° C., and infill of 5% to 100%, preferably 20%. After creating the data for modeling, import the data for modeling into a 3D printer (Moth Mach S3DP224) of the hot melt deposition method and perform 3D printing with polylactic acid filament (PolyLite PLA). The support of the model is removed by hand to complete the polylactic acid denture base model.
Fix the framework and the denture base model made on the working model with wax. Also, the artificial tooth is fixed to the artificial tooth socket with wax.

The working model with the framework, denture base model and artificial teeth fixed is embedded in a dental flask with gypsum. Specifically, a dental flask is coated with a layer of petroleum jelly, and a denture base prototype to which artificial teeth are fixed is fixed to a working model with wax. After the primary burial is completed, a gypsum separating material is applied to the hardened gypsum, the upper portion of the flask is set to the lower portion of the flask, and secondary burial is performed with gypsum. At the time of burial, it is preferable to fix the denture base prototype with the artificial teeth fixed to the working model with wax, and then bury it with gypsum. You can bury yourself. As for the gypsum used for burial, ordinary gypsum is preferable, but hard gypsum or ultra-hard gypsum is used only for the parts that come into contact with the artificial tooth or denture base model for the purpose of improving the surface properties and improving the strength of the negative mold. can be

After the implantation is completed, the embedded dental flask is submerged in hot water for 1 to 5 minutes to divide the embedded dental flask into upper and lower parts. At the same time as the division, the denture base model softened with hot water is removed. Then, a resin separating material (alginate varnish) is applied to the gypsum portion of the divided denture negative mold (completion of the denture negative mold).

After the denture negative mold is completed, the powder (polymer) and liquid (monomer) of the heat-polymerized resin for denture base (Urban) are mixed. When the mixture of the heat-polymerized resin for denture base changes from sand-like to rice cake-like, the mixture of heat-polymerized resin for denture base is press-filled into the denture negative mold. After filling the denture base heat-polymerizing resin mixture into the denture mold, the dental flask is fixed with bolts and screws, and the dental flask is placed in a heat-polymerizing machine (Aquamarathon) for polymerization. In this example, a heat-polymerized resin for denture base was used, but a normal temperature-polymerized resin for denture base (fit resin) may also be used.

After the completion of polymerization of the heat-polymerized denture base resin, stress relaxation is performed for a minimum of 720 minutes. After stress relaxation, the denture is indexed from the denture negative mold using gypsum forceps. After the full denture is indexed, it is immersed in a gypsum solution (supermelt) for 30 to 120 minutes to chemically remove gypsum adhering to the denture base.
Remount the fabricated partial denture on the articulator and adjust the occlusion. Finally, the denture is mirror-polished to complete the partial denture.

(Manufacturing of denture base model)
After outputting the design data of the complete denture, the design data was imported into the slicer software (SIMPLIFY3D) to create modeling data in the same manner as in the above example of manufacturing the complete denture. The modeling conditions for creating the modeling data were as follows: polylactic acid was selected as the material, the modeled object was placed horizontally with respect to the Z axis, automatic support was set, the diameter of the nozzle was 0.4 mm, and the layer pitch was 0.4 mm. 100 mm, extruder temperature of 190° C., bed temperature of 60° C., and infill density of 35%. Fig. 1 shows modeling data for a denture base with an infill density of 35%. It can be confirmed from FIG. 1 that by setting the infill density to 35%, the ratio of internal filling of the denture base data is 35%.
After creating the data for modeling, the data for modeling was imported into a fused deposition type 3D printer (Moth Mach S3DP224), and 3D printing was performed with a polylactic acid filament (PolyLite PLA). A model with supports is shown in FIG. Moreover, as a result of performing a surface deviation analysis on the design data of the model, it was confirmed that the modeling tolerance of the model was within a range of ±0.2 mm with respect to the design data.
The model's support was then removed and the model was embedded twice with gypsum in a dental flask. After gypsum hardening, the dental flask was immersed in hot water at 65° C. for 3 minutes and the softened model was removed using an Evans knife. FIG. 4 shows the model that has been softened and removed. Since the model has an infill density of 35%, it can be easily deformed and removed by heating.
Finally, the rice cake-like heat-polymerized resin (Urban) is press-fitted into the prepared negative mold, the dental flask is fixed with bolts and screws, and the dental flask is attached to the heat-polymerizing machine (Aquamarathon). was added and polymerized. After 720 minutes of stress relaxation, the denture base made of heat-polymerized resin was indexed from the negative mold. Fig. 5 shows the determined denture base made of heat-polymerized resin. In addition, as a result of analyzing the surface deviation of the denture base made of heat-polymerized resin prepared in this example, the modeling tolerance with respect to the design data was within a range of ±0.2 mm, indicating that the denture was manufactured with high accuracy. confirmed.

The thermoplastic resin denture base model according to the invention enables the production of a denture base model with a 3D printer, and is useful for improving the quality and uniformity of dentures in the dental field.

Claims (9)

A denture base prototype used for manufacturing dentures by a resin polymerization method,
Equipped with artificial tooth sockets,
A denture base prototype characterized by being made of a thermoplastic resin having a softening point of 30°C to 90°C. The denture base master according to claim 1, wherein the thermoplastic resin is selected from polylactic acid resin, PET resin, and PVA resin. The denture base master mold according to claim 1, wherein the thermoplastic resin is a polylactic acid resin. The denture base model according to claim 1, wherein the artificial tooth socket is positioned to reproduce a standard dentition. 2. The denture base model according to claim 1, wherein the artificial tooth socket is positioned to reproduce patient-specific dentition. A method of manufacturing a denture base model used for manufacturing dentures by a resin polymerization method, characterized by using a 3D printer based on a hot-melt lamination method. The method of manufacturing a denture base model according to claim 6, wherein the infill density is 5% to 40%. 7. The method of manufacturing a denture base model according to claim 6, wherein the raw material is polylactic acid resin. A method for producing a denture base by a resin polymerization method, comprising:
Using a thermoplastic resin denture base prototype with a softening point of 30° C. to 90° C. as the denture base prototype,
a step of fixing an artificial tooth to the denture base model;
A step of burying the denture base model to which the artificial teeth are fixed with plaster;
a step of softening the denture base model by heating to remove the denture base model;
A step of filling the denture negative mold with resin and polymerizing the resin,
A fabrication method comprising:

Images