Manufacturing method of heat-softened dental tray

Abstract

To provide a dental tray in which an impression material is not easily peeled off from the tray and a cured model material can be easily removed from impression.SOLUTION: A dental tray is used for impression taking in dental treatment. The dental tray is made of a thermoplastic resin in which a softening point is 30 to 90°C, and an arithmetic average roughness of the surface is Ra 1.0 μm or more and Rz 6.0 μm or more.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to dental instruments, and more particularly to trays used for taking impressions in the dental field. [Background technology]

[0002] A dental tray is an instrument used for taking impressions in dental treatment. Taking an impression involves filling a dental tray with an impression material such as silicone, alginate or agar, inserting the impression material into the oral cavity and pressing it against the dentition and jaw, and removing it from the oral cavity after the impression material has hardened. A dental model is then made by injecting a model material such as gypsum or resin into the impression obtained by the impression taking and removing the model material from the impression. The dental model is used for examination and diagnosis and for making devices to be placed in the oral cavity.

[0003] When the impression material is removed from the teeth, the impression material may peel off from the tray. When the impression material peels off from the tray, the shape of the impression is likely to change significantly, which causes a problem that a highly accurate impression cannot be obtained. To solve this problem, for example, Patent Document 1 discloses a method of making it difficult for the impression material to peel off from the tray by using an adhesive to bond the impression material and the impression tray.

[0004] Another problem is that when removing the hardened model material from the impression in the above-mentioned dental model manufacturing process, the hardened model material cannot be easily removed from the impression due to undercuts in the model, and therefore, the dental tray must be broken to remove the hardened model material.

[0005] Various methods have been studied for removing the hardened model material without damaging the model. For example, Patent Document 2 discloses a method for easily removing the impression material from the model by dividing the tray. Patent Document 3 discloses a dentition impression tray made of Ni-Ti or Ni-Ti-Cu shape memory alloy with a shape recovery start temperature of 40°C or higher. Although these methods allow the model to be removed without damaging it, the tray itself is costly. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Published Patent Application No. 2010-270070 [Patent Document 2] Unexamined Patent Publication No. 61-25546 [Patent Document 3] Published Patent Application No. 11-267138 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a dental tray in which the impression material is unlikely to peel off from the tray and the hardened model material can be easily removed from the impression. [Means for solving the problem]

[0008] The present invention includes the following inventions. [1] A dental tray used for taking impressions in dental treatment, characterized in that the dental tray is made of a thermoplastic resin having a softening point of 30 to 90°C and has a surface arithmetic mean roughness of Ra 1.0 μm or more and Rz 6.0 μm or more. [2] The dental tray according to [1], characterized in that the softening point of the thermoplastic resin is 40°C to 70°C. [3] The dental tray according to [1], characterized in that the surface roughness is Ra 3.0 μm or more and Rz 18.0 μm or more. [4] A dental tray as described in [1], characterized in that the thermoplastic resin is a polylactic acid-based resin or a PET-based resin. Effect of the Invention

[0009] The dental tray manufacturing method of the present invention is different from conventional dental trays in that the impression material is less likely to peel off from the tray, and a highly accurate impression can be obtained. In addition, the dental tray itself is softened by heating, so that the model material can be easily removed from the impression, and a dental model can be produced in a short time. Since the tray is softened, damage to the model that can occur when removing the hardened model material from the impression does not occur. [Brief description of the drawings]

[0010] [Figure 1] Appearance photograph of dental tray according to Example 1 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The method for producing a dental tray of the present invention is a method for producing a tray used for taking an impression. The tray may have a handle or a hole, and may have any shape.

[0012] The dental tray of the present invention can be manufactured by any method, such as injection molding, a manufacturing method using a 3D printer, etc. Among them, by using a 3D printer using a fused deposition modeling method, any shape can be easily manufactured, and a dental tray can be manufactured inexpensively and in a short time.

[0013] The dental tray of the present invention is made of a thermoplastic resin having a softening point of 30 to 90° C. and softens when heated, allowing the model to be easily removed.

[0014] Thermoplastic resins having a softening point of 30° C. to 90° C. can be used without any problems, but from the viewpoints of removability, operability, ease of removal in the case of an undercut shape, and work safety, it is preferable that the softening point is 40° C. to 70° C. In particular, thermoplastic resins having a softening point of 50° C. to 60° C. are most preferably used.

[0015] Here, the softening point refers to the point at which an amorphous solid such as glass or plastic suddenly becomes more fluid as it passes through a relatively narrow temperature range when the temperature is increased. The measurement method is based on the ASTM D1525 (ISO306GB / T163 3) test method, in which a test piece of a specified size is placed in a heating bath, and the temperature of the bath is increased while the end face of a certain cross-sectional area is pressed against the center. The temperature is then recorded when the end face of the test piece penetrates to a depth of 1.0 mm.

[0016] The thermoplastic resin in the manufacturing method 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., and any resin can be used, such as polylactic acid resin, PET resin, ABS resin, ASA (acrylonitrile styrene acrylate), polyvinyl chloride, etc. Here, polylactic acid resin and PET resin are preferred from the viewpoints of removability of the model, operability during removal, operational safety in the heating step, and environmental load due to the ability to reuse as a raw material after use.

[0017] When a polylactic acid-based resin is used as the thermoplastic resin, it can be particularly preferably used. When a polylactic acid-based resin is used, it is particularly excellent in terms of removability of the model, operability during removal, work safety in the heating process, environmental load due to reusability as a raw material, low CO2 generation during the manufacturing process, and low cost of raw materials. When a polylactic acid-based resin is used, it can be particularly useful as a disposable tray.

[0018] The dental tray of the present invention is characterized in that the arithmetic mean roughness of the surface is Ra 1.0 μm or more and Rz 6.0 μm or more. The above surface roughness improves the adhesive strength between the impression material and the tray. From the viewpoint of improving the adhesive strength between the impression material and the tray, the surface roughness is more preferably Ra 3.0 μm or more and Rz 18.0 μm or more, and particularly preferably Ra 5.0 μm or more and Rz 30.0 μm or more.

[0019] When measuring surface roughness, if fine molding marks remain due to the manufacturing method, which is likely to occur when manufacturing using a 3D printer, etc., the roughness is measured in a direction perpendicular to the molding marks (a direction crossing the molding marks).

[0020] To improve adhesion, the dental trays of the present invention may be perforated.

[0021] In the method for manufacturing a dental tray of the present invention, when manufacturing using a 3D printer, layered manufacturing may be performed under modeling conditions for a hollow shape, or layered manufacturing may be performed under modeling conditions for a close-packed shape.

[0022] The internal structure of the dental tray of the present invention can be prepared arbitrarily, but considering the ease of softening by heating, ease of removal, time required for preparing the dental tray, raw material cost, etc., it is preferable that the internal structure has a cavity. The internal structure can be easily adjusted by appropriately setting the density (infill density) in the case of, for example, a 3D printer. The density (infill density) is preferably 5 to 80%, particularly preferably 20 to 60%, and most preferably 20 to 40%. The above density (infill density) can be most preferably used in terms of the denture base master model being less likely to deform, the molding time, ease of removal, ease of removal in the case of an undercut shape, etc.

[0023] The 3D printer may have a single discharge nozzle or may have multiple discharge nozzles. There are no particular limitations on the discharge nozzle, but for example, a nozzle with a hole diameter at the nozzle tip of preferably 0.1 to 3.0 mm, more preferably 0.3 to 1.0 mm, can be used.

[0024] The dental tray manufactured by the manufacturing method of the present invention is characterized in that the impression material is not easily peeled off from the tray. By manufacturing the tray using a 3D printer based on the fused deposition modeling method, it is possible to easily form a fine uneven shape with a surface roughness of Ra 1.0 μm or more and Rz 10.0 μm or more on the entire surface of the tray, which generates a physical interlocking force between the dental tray and the impression material and increases the contact surface area.

[0025] From the viewpoint of easily forming a fine uneven shape with a surface roughness of Ra 1.0 μm or more and Rz 10.0 μm or more, the discharge nozzle diameter of the 3D printer is preferably 0.1 to 3.0 mm, and particularly preferably 0.3 to 1.0 mm.

[0026] The dental tray of the present invention may be an individual tray that is shaped to match a patient's unique shape based on the shape of a study model. A study model is a model made by injecting a model material into a rough impression.

[0027] In the method for producing a dental model using the dental tray of the present invention, a dentist takes an impression using the dental tray and impression material of the present invention, then injects a model material into the impression, and after the model material has completely hardened, the tray is softened by heating and the hardened model material is removed. The model material is preferably gypsum or a resin that hardens at room temperature. The tray may be heated by hot water, a microwave oven, or dry heating in an oven. EXAMPLES

[0028] (Making dental trays) After outputting the design data for the dental tray, the design data was imported into slicer software (SIMPLIFY 3D) to create modeling data. The modeling conditions for creating the modeling data were as follows: thermoplastic resin was selected as shown in Table 1, the model was placed horizontally with respect to the Z axis, automatic support was set, and the layer pitch was 0.100 mm. Note that the nozzle diameter was 0.1 mm in Example 1, 0.4 mm in Examples 2 to 4 and 6, and 0.6 mm in Example 5. The infill density was 35%. After creating the modeling data, the data was imported into a fused deposition modeling 3D printer (Moth Mach S 3 DP 2 2 4) and 3D printed using filament of the material shown in Table 1, and the supports for the model were removed. For the comparative example, an injection molded product was used. (Surface roughness measurement) The surface roughness of the obtained molded object was measured using a surface roughness measuring instrument (Surfcom 1500SD / DX, manufactured by Tokyo Seimitsu Co., Ltd.) (N=3). (Checking the ease of removing the model) The impression material (Jildefit (Shofu)) was poured into the prepared dental tray, an impression of the subject's mouth was taken, and after checking the adhesiveness of the impression material, plaster (Modelock II (Shofu)) was poured in. After the plaster hardened, it was immersed in 65°C hot water for 3 minutes to soften the dental tray and impression material, and the ease of removal was confirmed.

[0029] (Adhesion of impression materials) ◎: No peeling at all ○: There is some peeling on the edge, but it does not affect the accuracy of the model. △: Partial peeling occurs ×: Peeling off (Ease of removing the model) ◎: The model can be easily removed 〇: The model can be removed without any problems △: Removing the model is difficult and time-consuming ×: Difficult to remove and damages the model

[0030] [Table 1]

[0031] [Table 2] [Industrial Applicability]

[0032] The dental tray of the present invention can be produced at low cost and is useful for improving the quality and production efficiency of dental models in the dental field.

Claims

1. A dental tray used for taking impressions in dental treatment, the dental tray being made of a thermoplastic resin having a softening point of 30 to 90°C and having an arithmetic mean roughness of the surface of Ra 1.0 μm or more and Rz 6.0 μm or more.

2. 2. The dental tray according to claim 1, wherein the softening point of the thermoplastic resin is 40°C to 70°C.

3. 2. The dental tray according to claim 1, characterized in that the arithmetic mean roughness of the surface is Ra 3.0 μm or more and Rz 18.0 μm or more.

4. 2. The dental tray according to claim 1, wherein the thermoplastic resin is a polylactic acid-based resin or a PET-based resin.

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