Zirconia porous molding for dentistry cutting in which color tone is non-linearly adjusted, and manufacturing method of the same

Abstract

To provide a method for making changes in contrast or intensity of color in a porous molding (and / or sintered body thereof) itself closer to those of a natural tooth, and making the porous molding (and / or sintered body thereof) itself have an external appearance closer to a natural tooth.SOLUTION: A method for impregnating impregnation solution containing a metal element and a solvent into a porous molding for dentistry cutting includes a contact step of bringing the impregnation solution containing the metal element and the solvent in contact with a front layer surface of at least one of the porous molding for dentistry cutting to form one or more contact parts 3. In the case where a first virtual line and a second virtual line orthogonal to the first virtual line are defined on the front layer surface to which the impregnation solution contacts, the impregnation solution is brought in contact to form one or more contact parts 3 such that a non-contact part 4 to which the impregnation solution does not contact is present on at least one side of the first virtual line, and the non-contact part 4 to which the impregnation solution does not contact is present on at least one side of the second virtual line, in the contact step.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a colored porous body for dental cutting processing and a porous body for dental cutting processing manufactured by said manufacturing method, and more specifically to a method for manufacturing a color-adjusted porous body for dental cutting processing for producing dental restorations using CAD / CAM, and a porous body for dental cutting processing manufactured by said manufacturing method. [Background technology]

[0002] In recent years, the technology of producing prosthetic devices by cutting using dental CAD / CAM systems has rapidly spread. This has made it possible to easily produce prosthetic devices by processing workpieces made of ceramic materials such as zirconia, alumina, and lithium disilicate, and resin materials such as acrylic resin and hybrid resin.

[0003] In particular, zirconia has been used in clinical applications in a variety of cases due to its high strength. However, fully sintered zirconia (hereinafter referred to as zirconia sintered body) has a very high hardness, so zirconia sintered bodies are often prepared by calcining at a temperature lower than the fully sintered temperature and adjusted to a hardness suitable for cutting (pre-sintered zirconia), and then re-firing after cutting to obtain the zirconia sintered body.

[0004] On the other hand, in order to further improve the aesthetics in the oral cavity, it is necessary to make the appearance of the prosthetic device similar to that of natural teeth, and attempts have been made to reproduce the same appearance (especially color tone and translucency) of natural teeth using zirconia (sintered body) itself. Patent Document 1 discloses a method for partially coloring a dental calcined body by using a coloring liquid and a penetrating liquid material that limits the penetration of the coloring liquid. However, this method does not allow the colored portion to be colored in a shape that includes a curve, making it difficult to reproduce the appearance of a natural tooth. Patent Document 2 discloses a dental mill blank having a laminated structure in which a curved body layer is disposed inside an enamel layer. However, this blank is manufactured by laminating powdered raw materials, and since there is a clear boundary between the enamel layer and the body layer, it is difficult to reproduce the appearance of a natural tooth. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6093900 [Patent Document 2] International Publication No. 2019 / 131787 Summary of the Invention [Problem to be solved by the invention]

[0006] Conventional color-adjusted porous bodies are composed of parallel layers colored in tooth color, so that when the porous body is a pre-sintered body for dental cutting, for example, the porous body (and / or its sintered body) itself cannot express a color tone similar to that of natural teeth in terms of color shading and intensity. Therefore, there has been a demand for the porous body (and its sintered body) itself to have an appearance closer to that of natural teeth. Furthermore, there has been a demand for a method of adjusting the color tone of a porous body that can easily reproduce detailed tooth color designs.

[0007] As a result of intensive research into the manufacturing method of a porous molded body for dental cutting, it was found that by adjusting an impregnation solution containing a metal element and a solvent and making the contact area of ​​the surface of the porous molded body with the impregnation solution a specific range, the change in color tone and intensity of the porous molded body (and its sintered body) can be made closer to that of natural teeth, and the porous molded body (and its sintered body) can have an appearance closer to that of natural teeth. The details of the present invention are described below. [Means for solving the problem]

[0008] The present invention relates to a method for impregnating a porous body for dental cutting with an impregnation solution containing a metal element and a solvent, comprising the steps of: A contacting step is included in which an impregnation solution containing a metal element and a solvent is brought into contact with at least one surface of a porous molded body for dental cutting to form one or more contact portions; When a first virtual line and a second virtual line perpendicular to the first virtual line are defined on a surface that comes into contact with the impregnation solution, In the contacting step, The present invention provides a method for forming one or more contact portions by contacting the impregnation solution such that a non-contact portion that does not come into contact with the impregnation solution exists on at least one side of a first virtual straight line, and a non-contact portion that does not come into contact with the impregnation solution exists on at least one side of a second virtual straight line.

[0009] The present invention also provides A method for supporting a metal element on a porous molded body for dental cutting, comprising the steps of: a contacting step of contacting at least one surface of the porous molded body for dental cutting with an impregnation solution containing a metal element, a solvent, and a metal element support to form one or more contact portions; A supporting step of supporting the metal element contained in the impregnation solution on the porous body for dental cutting processing, When a first virtual line and a second virtual line perpendicular to the first virtual line are defined on a surface that comes into contact with the impregnation solution, In the contacting step, the impregnation solution is A non-contact portion that is not in contact with the impregnation solution is present on at least one side of the first virtual line, and A method for forming one or more contact portions such that a non-contact portion that is not in contact with the impregnation solution exists on at least one side of the second imaginary line is provided. Effect of the Invention

[0010] According to the present invention, the changes in color shade and intensity in the porous molded body (and / or its sintered body) itself can be made to be closer to those of natural teeth, so that the porous molded body (and / or its sintered body) itself has an appearance closer to that of natural teeth. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a surface (contact surface) of a zirconia pre-sintered body for dental cutting according to a first embodiment, which is in contact with an impregnation solution. [Diagram 2] Schematic diagram of the impregnation state of the impregnation solution in the pre-sintered zirconia for dental cutting in Figure 1 [Diagram 3] Schematic diagram of the surface (contact surface) of the zirconia pre-sintered body for dental cutting according to the second embodiment that comes into contact with the impregnation solution. [Figure 4] Schematic diagram of the impregnation state of the impregnation solution in the zirconia pre-sintered body for dental cutting in Figure 3 [Diagram 5] Schematic diagram of the surface (contact surface) of the zirconia pre-sintered body for dental cutting according to the third embodiment that comes into contact with the impregnation solution. [Figure 6] Schematic diagram of the impregnation state of the impregnation solution in the zirconia pre-sintered body for dental cutting in Fig. 5 [Figure 7] Schematic diagram of the case where the impregnating solution is brought into contact with the surface (contact surface) in a state where the surface (contact surface) is inclined relative to the horizontal plane. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] In the present invention, in the contact step, the area ratio of the contact portion to the non-contact portion of the surface layer that comes into contact with the impregnation solution is 5.0 × 10 -4 The impregnation solution can be contacted such that the R 2 O 3 is 1.2.

[0013] In the present invention, the amount of impregnation solution to be impregnated into one contact portion is 0.01 g / mm 2 It can be more than that.

[0014] In the present invention, in the contacting step, the impregnation solution can be brought into contact with the porous formed body in such a manner that the impregnation solution does not permeate the entire porous formed body.

[0015] In the present invention, the metal element contained in the impregnation solution may be one or more elements selected from the group consisting of rare earth metal elements and transition metal elements.

[0016] In the present invention, the metal element contained in the impregnation solution may be one or more selected from the group consisting of yttrium, cerium, terbium, nickel, iron, erbium, cobalt, niobium, titanium, praseodymium, zirconium, vanadium, niobium, tantalum, and chromium.

[0017] In the present invention, the impregnation solution may contain at least one metal element support material for supporting a metal element on the porous molded body for dental cutting.

[0018] In the present invention, the metal element support material may be an organic compound.

[0019] In the present invention, the metal element-supporting material may be one or more selected from the group consisting of oxycarboxylic acids, glycols, and combinations thereof.

[0020] In the present invention, the method according to claim 1, wherein the shape of the contact portion is circular or elliptical.

[0021] In the present invention, the diameter or major axis of the contact portion may be 0.5 to 15 mm.

[0022] In the present invention, the contact portion can be defined by a masking material.

[0023] In the present invention, the impregnation solution can permeate 1.0 mm or more from the center of the contact portion in a direction perpendicular to the surface layer surface with which the impregnation solution comes into contact.

[0024] In the present invention, the impregnation solution can be brought into contact with the porous molded body for dental cutting so that the impregnated area of ​​the impregnation solution has a curve with an R value of 0.3 mm to 250 mm inside the porous molded body for dental cutting.

[0025] In the present invention, the porous molded body for dental cutting may be a pre-sintered zirconia body for dental cutting.

[0026] In the present invention, in the supporting step, the metal element in the impregnation solution can be supported on the porous formed body by heating at a temperature equal to or lower than the boiling point of the solvent in the impregnation solution.

[0027] In the present invention, in the supporting step, the metal element in the impregnation solution can be supported on the porous formed body by heating at a temperature of 50 to 170°C.

[0028] In the present invention, the metal element support material may be an organic compound.

[0029] In the present invention, the metal element support material may be one or more selected from the group consisting of oxycarboxylic acids, glycols, and combinations thereof.

[0030] The present invention provides a method for producing a dental sintered body by sintering a porous molded body for dental cutting impregnated with an impregnation solution by the method of the present invention, and a method for producing a dental sintered body by sintering a porous molded body for dental cutting carrying a metal element by the method of the present invention.

[0031] The present invention can form a color tone adjustment region with a three-dimensional curved shape and gradation inside the porous molded body for dental cutting. As a result, the dental restoration obtained from the porous molded body for dental cutting has excellent aesthetics, high color reproducibility, and can reproduce the dentin shape of the mamelon part, the cervical part, etc. Furthermore, the porous molded article for dental cutting of the present invention can reproduce the shade of coloring and has no clear color transitions, resulting in a more aesthetic appearance.

[0032] Hereinafter, one embodiment of the present invention will be specifically described. [Porous compact] The porous molded body in the present invention may be, for example, a zirconia pre-sintered body. The zirconia pre-sintered body contains zirconia and a stabilizing material that suppresses the phase transition of zirconia. The stabilizing material is not particularly limited, but examples thereof include yttria, ceria, calcia, and magnesia. The present invention may include a step of preparing such a porous molded body (porous molded body preparation step) or a step of preparing a zirconia pre-sintered body (zirconia pre-sintered body preparation step).

[0033] The crystal phase of the zirconia pre-sintered body in the present invention is preferably tetragonal and / or cubic. If the crystal phase is monoclinic, sufficient translucency may not be imparted after complete sintering of the zirconia, which is not preferable.

[0034] The method for producing the zirconia pre-sintered body of the present invention is not particularly limited, and any known production method can be used without any problems. Specifically, it is preferable to produce the zirconia pre-sintered body by pressure molding zirconia powder and calcining the resulting zirconia molded body. There is no particular limit to the method for producing the zirconia powder used for the zirconia pre-sintered body, and any known method can be used. Specifically, it is preferable that the zirconia powder used in the present invention is produced by a hydrolysis method.

[0035] The zirconia powder used in the manufacture of the zirconia pre-sintered body of the present invention may contain a coloring agent. Specifically, iron oxide for imparting a yellow color and erbium for imparting a red color may be used. In addition to these coloring agents, coloring agents containing elements such as cobalt, manganese, and chromium may be used in combination to adjust the color tone without any problem. The zirconia powder containing a coloring agent can increase the variety of coloring to the tooth color. The zirconia powder used in the manufacture of the zirconia pre-sintered body of the present invention may not contain a coloring agent.

[0036] The zirconia powder used in the production of the zirconia pre-sintered body of the present invention may contain a sintering aid, examples of which include alumina and silica.

[0037] The primary particle size of the zirconia powder used in the production of the zirconia pre-sintered body in the present invention is preferably 1 to 500 nm. If the primary particle size is less than 1 nm, the translucency of the zirconia sintered body is improved, but it tends to be difficult to impart sufficient strength to the zirconia sintered body. On the other hand, if the primary particle size is more than 500 nm, it tends to be difficult to impart sufficient strength to the zirconia sintered body.

[0038] A zirconia molded body can be obtained by pressure molding the zirconia powder into a desired shape. The pressure during pressure molding is not particularly limited, but a surface pressure of 5 to 120 MPa is preferable, and a surface pressure of 30 to 100 MPa is even more preferable.

[0039] The obtained zirconia molded body is preferably subjected to isostatic pressing by hot isostatic pressing (HIP treatment) or cold isostatic pressing (CIP treatment), and is particularly preferably subjected to CIP treatment. The maximum load pressure of the CIP treatment is preferably 50 MPa or more. If the maximum load pressure is less than 50 MPa, sufficient translucency and strength may not be imparted to the zirconia sintered body. The holding time at the maximum load pressure of the CIP treatment is not particularly limited, but is usually preferably 0 to 150 seconds, and more preferably 0 to 60 seconds.

[0040] By calcining the zirconia molded body, a pre-sintered zirconia body can be obtained as a porous molded body. In the present invention, the term "calcination" refers to firing the zirconia molded body at a temperature 100 to 600°C lower than the complete sintering temperature. The particles are temporarily bonded together by the calcination, resulting in a state in which continuous pores are formed between the particles through which a solution can penetrate.

[0041] The calcination temperature of the zirconia pre-sintered body in the present invention is preferably 800 to 1200° C. If the calcination temperature is less than 800° C., the Vickers hardness and / or bending strength will be too low, and chipping or fracture will tend to occur during cutting. On the other hand, if the calcination temperature is 1200° C. or more, the Vickers hardness and / or bending strength will be too high, and the milling bur of the cutting machine will be worn out rapidly, and the running cost will tend to be high.

[0042] The relative density of the zirconia pre-sintered body to the density of the completely sintered zirconia sintered body is preferably 40 to 70%, more preferably 45 to 65%, and particularly preferably 50 to 60%.

[0043] The porous molded body in the present invention is not limited to the above-mentioned zirconia pre-sintered body, and may be, for example, alumina or lithium disilicate. The manufacturing method of these porous molded bodies is not particularly limited, and they may be manufactured by the same method as the manufacturing method of the above-mentioned zirconia pre-sintered body, or may be manufactured by a conventionally known method. In addition, the sintered state of the porous molded body in the present invention is not particularly limited, and it may be a molded body that has not been pre-sintered, or may be a molded body that has been completely sintered.

[0044] [Impregnation solution] The impregnation solution in the present invention is a solution containing a metal element and a solvent, and is, for example, a solution prepared by an impregnation solution preparation step described below.

[0045] The impregnation solution preparation process of the present invention is a process for obtaining an impregnation solution by mixing a metal element and a solvent, and the mixing method is not particularly limited as long as each material is mixed uniformly. For example, mixing with a glass rod or the like, mixing by a stirrer, a tumbling mixing method in which the entire container containing each material is turned upside down several times to mix the materials, and mixing with an ultrasonic homogenizer can be mentioned.

[0046] Metal elements used in the impregnation solution may also include metalloid elements such as boron and silicon. By using a plurality of these metal elements as necessary, translucency and color can be freely reproduced, and a rich color expression can be achieved. Specific metal elements are preferably rare earth metal elements, and also preferably transition metal elements. Specifically, yttrium, calcium, cerium, terbium, nickel, iron, erbium, cobalt, niobium, titanium, praseodymium, zirconium, vanadium, niobium, tantalum, and chromium are more preferable, and yttrium, nickel, iron, erbium, cobalt, praseodymium, zirconium, niobium, and tantalum are particularly preferable.

[0047] The metal ion concentration of the impregnation solution in the present invention is not particularly limited, but for example, in the case of yttrium ions, it is preferably about 2.0wt% to 10.0wt%. If it is less than 2.0wt%, the amount of yttrium supported on the porous molded body for dental cutting processing is small, and sufficient characteristics may not be obtained. If it is more than 10.0wt%, the amount of yttrium supported on the porous molded body for dental cutting processing is large, and physical properties may be adversely affected. Since the optimal metal support amount varies depending on the type of metal and the desired characteristics, it is preferable to determine the metal ion concentration of the impregnation solution based on the desired metal support amount and the solubility of the metal ion source in the solvent.

[0048] The impregnation solution of the present invention preferably contains a metal element-supporting material for the porous molded body. The metal element-supporting material is used for the purpose of supporting the metal element in the impregnation solution inside the porous molded body.

[0049] The term "support" as used herein means, for example, that the impregnation solution is permeated into the porous body and the metal element in the impregnation solution is precipitated and precipitated within the porous body. It also includes the metal element being left in the porous body by increasing the viscosity and / or solidifying the impregnation solution.

[0050] The metal element support material is preferably one that is decomposed or made highly viscous mainly by heat treatment. When an impregnation solution that does not contain a metal element support material is used, the metal element tends to segregate near the surface of the porous body as the solvent evaporates due to drying after the impregnation step. Therefore, it is preferable to use a metal element support material to deposit or precipitate the metal element in the impregnation solution in the porous body by heat treatment, or to make the impregnation solution highly viscous so that the metal element does not move to the surface of the porous body and remains there.

[0051] The metal element support material for precipitating and depositing the metal element is preferably an organic compound, examples of which include urea, hexamethylenetetramine, dimethyl oxalate, etc., and it is preferable to use urea. By heat-treating these metal element support materials, the metal element can be precipitated and deposited in the porous molded body.

[0052] Examples of metal elements that are precipitated and precipitated on the porous molded body include, but are not limited to, metal oxides, metal hydroxides, metal oxyhydroxides, metal carbonates, metal carbonate hydroxides, metal oxalates, etc. Furthermore, there is no particular limitation on the form of the metal elements. They may be in any shape, such as spherical, plate-like, needle-like, or amorphous, and may be either crystalline or amorphous. Metal ions are supported on the porous molded body by these precipitations and precipitations.

[0053] The metal element support material, which increases the viscosity of the impregnation solution to leave the metal element in the porous body, is preferably an organic compound, more preferably an oxycarboxylic acid, a glycol, or a combination thereof. Citric acid and propylene glycol are particularly preferred. By heat treating these metal element support materials, the viscosity of the impregnation solution increases, allowing the metal element to remain in the zirconia pre-sintered body.

[0054] The solvent used in the impregnation solution is used as a carrier medium for permeating the metal element in the impregnation solution into the porous body. The solvent is not particularly limited as long as it has high wettability to the porous body. Specific examples include water, methanol, ethanol, n-propanol, isopropyl alcohol, acetone, and methyl ethyl ketone. These solvents can be used in combination as necessary. It is preferable to include water, ethanol, isopropyl alcohol, and acetone. Water is particularly preferable.

[0055] Examples of the metal ion source include acetates, citrates, and nitrates.

[0056] In the present invention, an acid, a base or a pH adjuster may be added to the impregnation solution for the purpose of controlling the pH. There is no particular limitation on the acid, base or pH adjuster used, but it is preferable to use an organic acid such as acetic acid or citric acid, or ammonia water, in order not to leave any residue on the zirconia pre-sintered body for dental cutting.

[0057] [Contact process] The contact step of the present invention is a step of contacting the surface of the porous body with the impregnation solution. The method of contacting the surface of the porous body with the impregnation solution is not particularly limited, but examples thereof include dripping the impregnation solution onto the porous body and painting the surface of the porous body with a brush.

[0058] The surface layer of the porous molded body in the present invention refers to all surfaces exposed to the atmosphere. For example, in the case of a rectangular porous molded body, all six surfaces exposed to the atmosphere are surface layers, and in the case of a cylindrical porous molded body, all three surfaces, the side surface corresponding to the circumference and the top and bottom surfaces forming a circle, are surface layers. In the contact step of the present invention, at least one surface layer of the porous molded body for dental cutting is contacted with an impregnation solution containing a metal element and a solvent to form one or more contact portions.

[0059] In the present invention, when a first virtual line and a second virtual line perpendicular to the first virtual line are defined on the surface with which the impregnation solution comes into contact, the impregnation solution forms one or more contact portions in the contacting step such that there is a non-contact portion on at least one side of the first virtual line with which the impregnation solution does not come into contact, and there is a non-contact portion on at least one side of the second virtual line with which the impregnation solution does not come into contact. For example, the contact portion and the non-contact portion can be formed by coating or masking a part of the surface of the porous molded body with a masking material that the impregnation solution does not penetrate. Examples of the masking material include Vaseline and vinyl tape, but are not particularly limited as long as the material is not permeable by the impregnation solution. The impregnation solution may be brought into contact with only a part of the surface of the porous molded body by coating, dripping, or the like, without coating or masking.

[0060] The shape of the contact part may be a polygon, a circle, or a combination of these, and the shape of the color tone adjustment area can be expressed in a variety of ways depending on the shape of the contact part and the amount of the impregnation solution to be infiltrated. The shape of the contact part is not particularly limited, but it is preferably a circle or ellipse with a diameter or major axis of 0.5 to 15 mm. In particular, for reproducing the tooth neck, it is preferable that the contact part be a circle or ellipse with a diameter or major axis of 0.5 to 6.0 mm, and in particular, for reproducing the mamelon part, it is preferable that the contact part be a circle or ellipse with a diameter or major axis of 0.5 to 1.0 mm.

[0061] In the contact step, the area ratio of the contact area to the non-contact area on the surface layer with which the impregnation solution comes into contact (if multiple contact areas are formed, the total area of ​​the multiple contact areas) is 5.0 × 10 -4 It is preferable that the impregnation solution is in contact with the ion exchange layer so that the impregnation solution has a viscosity of 1.0×10 to 1.2. -3 More preferably, it is 2.0×10 -3 It is more preferable that the ratio is 0.1 or less, and particularly 6.0×10 -3 It is preferable that the area ratio is 0.05 or less. When a plurality of contact portions are formed, the above area ratio is calculated based on the total area of ​​the plurality of contact portions.

[0062] The contact surface in the present invention is the surface layer surface of the porous molded body where the contact portion exists. For example, in a cylindrical porous molded body, the surface corresponding to the circumference is the side surface, and the surfaces forming the circle are the upper and lower surfaces, and when the upper surface is brought into contact with the impregnation solution, only the upper surface becomes the contact surface. When the upper and lower surfaces are brought into contact with the impregnation solution, the two surfaces, the upper surface and the lower surface, become the contact surfaces.

[0063] The amount of impregnation solution is 0.01 g / mm for each contact area. 2 It is preferable that the density is 0.01g / mm or more. 2 If it is less than this, the colored portion (for example, the support portion) will not have a curved shape macroscopically, and it may be difficult to reproduce the tooth color. Also, it is preferable not to allow the impregnation solution to permeate the entire porous molded body.

[0064] [Infiltration process] The present invention may further include a penetration step in which the impregnation solution brought into contact with the porous body in the contact step is penetrated into the porous body. There is no particular limitation on the penetration method, and various methods such as leaving the porous body in an air atmosphere or penetration under pressure or reduced pressure may be used.

[0065] The infiltration step is preferably performed until the entire amount of the contacted impregnation solution is infiltrated into the porous molded body. In the impregnation solution infiltration step, the temperature of the atmosphere during infiltration is preferably 0 to 40°C, more preferably 10 to 25°C, in order to prevent evaporation of the solvent. After the entire amount of the contacted impregnation solution is infiltrated into the porous molded body in the infiltration step, the supporting step described below is preferably performed within 3 hours, more preferably within 1 hour. If the contacted impregnation solution is left at room temperature for a long time after infiltration, the solvent in the impregnation solution may evaporate, and the metal element in the impregnation solution may segregate on the surface of the porous molded body. The impregnation solution infiltrated in the infiltration step is preferably infiltrated 1.0 mm or more from the center of the contact part on the contact surface in the direction perpendicular to the surface surface with which the impregnation solution is in contact. If it is 1.0 mm or less, the metal element supporting part may not have a curved shape macroscopically.

[0066] [Supporting process] The present invention may include a supporting step in which the metal element-supporting material in the impregnation solution is decomposed or made highly viscous by heat treatment, and the metal element in the impregnation solution is precipitated, sedimented, and left in the porous molded body. The temperature of the heat treatment in the supporting step can be set according to the metal element-supporting material. The heat treatment temperature in the case of precipitating and precipitating the metal element in the impregnation solution is preferably equal to or lower than the boiling point of the solvent in the impregnation solution. This is because if the solvent evaporates before the decomposition of the metal element-supporting material begins, segregation of the metal element occurs, and the metal element may not be supported while maintaining the desired shape. In addition, the heat treatment temperature in the case of making the metal element remain by increasing the viscosity of the impregnation solution is preferably 50 to 170°C, more preferably 60 to 120°C. If the heat treatment temperature is too high, the solvent may evaporate before the viscosity of the impregnation solution begins to increase, and the metal element may segregate.

[0067] In the present invention, the metal element support part that supports the metal element in the porous molded body in the supporting step preferably has a shape including a curve inside the porous molded body. In the present invention, in order to quantify the magnitude of the curve, the R value calculated by the following formula is used.

number

[0068] Since the solvent, unreacted matter, by-products, etc. may remain in the porous molded body after the supporting step, it is preferable to perform heat treatment. There is no particular restriction on the atmosphere during heat treatment, and it can be performed under inert gas or superheated steam. Since no special equipment is required, heat treatment in normal pressure air is preferable. There is no particular restriction on the heat treatment temperature, but it is preferable to perform heat treatment at 500°C to 1200°C with a heating rate of 1 to 100°C / min. If the heating rate is too slow, it takes a long time to degrease and the production efficiency is reduced. In addition, if the heating rate is too fast, the porous molded body may crack. During heat treatment, it can be anchored at any temperature, and there is no particular restriction on the anchoring temperature or the number of times. It is preferable to determine the anchoring temperature and the number of times depending on the solvent, unreacted matter, by-products, etc. These heat treatments can remove impurities, organic matter, and odors.

[0069] In this way, the manufacturing method of the present invention can obtain a porous molded body for dental cutting, in which metal elements are supported so as to have a curved surface shape inside. The obtained porous molded body for dental cutting is preferably cut, cut, and surface-polished to a desired size as necessary.

[0070] There is no particular restriction on the type of prosthetic device to be cut using the porous molded body for dental cutting of the present invention, and there is no problem with any prosthetic device such as an inlay, laminate, crown, bridge, etc. Therefore, there is no particular restriction on the shape of the porous molded body for dental cutting to produce a prosthetic device by cutting, and any shape of porous molded body for dental cutting can be used, such as a block shape corresponding to an inlay, laminate, crown, etc., or a disk shape corresponding to a bridge.

[0071] By completely sintering the porous green body for dental cutting of the present invention, a sintered porous green body for dental cutting can be obtained.

[0072] There is no particular restriction on the method of making the dental cutting porous molded body into a sintered state, but a simple and preferred method is normal pressure sintering. There is no particular restriction on the sintering temperature, but 1400 to 1600 ° C is preferred, and 1450 to 1550 ° C is particularly preferred. There is no particular restriction on the retention time at the maximum sintering temperature, but 1 minute to 12 hours is preferred, and 1 to 4 hours is particularly preferred. There is no particular restriction on the heating rate, but 1 to 400 ° C / min is preferred, and 3 to 100 ° C / min is particularly preferred. In addition, the dental cutting porous molded body of the present invention can be sintered at 1400 ° C to 1600 ° C without cutting to obtain a dental cutting sintered body in a sintered state of a prosthetic device, and then cut to obtain a prosthetic device.

[0073] The relative density of the sintered porous compact for dental cutting is preferably 98% or more of the theoretical density. The relative density is calculated by measuring density / theoretical density. If the relative density is 98% or less, the strength and translucency tend to decrease.

[0074] Next, an example of a specific embodiment of the contact of the impregnation solution in the contact step in the present invention will be described with reference to the drawings. Fig. 1 is a schematic diagram of the surface layer surface (contact surface) of the zirconia pre-sintered body for dental cutting as the porous molded body for dental cutting according to the first embodiment, which is in contact with the impregnation solution, and Fig. 2 is a schematic diagram of the impregnation state of the zirconia pre-sintered body for dental cutting in Fig. 1.

[0075] As shown in Fig. 1 and Fig. 2, the zirconia pre-sintered body 1 for dental cutting is configured in a so-called block shape having a substantially rectangular parallelepiped shape. In the embodiment of Fig. 1 and Fig. 2, the impregnation solution is brought into contact with the substantially square upper surface 2, and the zirconia pre-sintered body 1 is impregnated with the impregnation solution from one contact portion. More specifically, in the embodiment of Fig. 1 and Fig. 2, a first imaginary straight line IL1 and a second imaginary straight line IL2 are defined that are perpendicular to each other and pass through the center C of the substantially square upper surface 2 with a side length of r. Then, the impregnation solution is brought into contact with a circle having a radius of r / 4 from the center of the substantially square upper surface 2 to form a contact portion 3 having a circular shape of a radius of r / 4, and the zirconia pre-sintered body 1 is impregnated with the impregnation solution from this circular contact portion having a radius of r / 4.

[0076] Therefore, in the embodiment of Figures 1 and 2, the impregnating solution comes into contact with the upper surface 2 to form one contact portion 3 such that there are non-contact portions 4 that do not come into contact with the impregnating solution on both ends in the extension direction of the first imaginary straight line IL1, and there are non-contact portions 4 that do not come into contact with the impregnating solution on both ends in the extension direction of the second imaginary straight line IL2.

[0077] In FIG. 2, the impregnation state of the impregnation solution in the cross section of the zirconia pre-sintered body, which includes the first virtual straight line IL1 and is perpendicular to the upper surface 2, is shown by a permeated portion 5 permeated with the impregnation solution and a non-permeated portion 6 where the impregnation solution has not permeated. As shown in FIG. 2, in this embodiment, the impregnation solution permeates the zirconia pre-sintered body 1 so that the permeated portion 5 has a semi-elliptical shape. The reason for this semi-elliptical shape is considered to be that the impregnation of the impregnation solution in the zirconia pre-sintered body 1 progresses so as to spread three-dimensionally from the contact position at the contact portion 3 in the zirconia pre-sintered body 1. In this embodiment, the impregnation solution is impregnated into the zirconia pre-sintered body 1 from the contact portion 3 having a circular shape with a center radius of r / 4 formed on the substantially square upper surface 2. Therefore, the impregnation state of the impregnation solution in the cross section of the zirconia pre-sintered body including the second virtual straight line IL2 and perpendicular to the upper surface 2 is the same as the impregnation state of the impregnation solution in the cross section of the zirconia pre-sintered body 1 including the first virtual straight line IL1 and perpendicular to the upper surface 2, as shown in FIG. 2. Therefore, in this embodiment, the permeated portion 5 has a substantially semi-ellipsoidal shape. Thus, in this embodiment, the boundary between the permeated portion 5 and the non-permeated portion 6 has at least a part of a curved shape in both the cross section of the zirconia pre-sintered body including the first virtual straight line IL1 and perpendicular to the upper surface 2 and the cross section of the zirconia pre-sintered body including the second virtual straight line IL2 and perpendicular to the upper surface 2. That is, in this embodiment, at least a part of the boundary between the permeated portion 5 and the non-permeated portion 6 can be made into a three-dimensional curved shape, so that a color tone adjustment region having a three-dimensional curved shape can be formed inside the zirconia sintered body for dental cutting.

[0078] In the above embodiment, the first imaginary straight line IL1 and the second imaginary straight line IL2 are defined so as to pass through the center C of the upper surface 2, but the first imaginary straight line IL1 and the second imaginary straight line IL2 can be defined arbitrarily on the surface layer surface that comes into contact with the impregnating solution, as long as there is a non-contact portion on at least one side of the first imaginary straight line that does not come into contact with the impregnating solution, and there is a non-contact portion on at least one side of the second imaginary straight line that does not come into contact with the impregnating solution. However, for example, as in the above embodiment, the first imaginary straight line IL1 and the second imaginary straight line IL2 can be defined so as to pass through the center of gravity of the surface layer surface that comes into contact with the impregnating solution, or can be defined so as to pass through the center of gravity of the contact portion 3.

[0079] FIG. 3 is a schematic diagram of a surface (contact surface) of a pre-sintered zirconia body for dental cutting according to a second embodiment, which is in contact with an impregnation solution, and FIG. 4 is a schematic diagram of the impregnated state of the pre-sintered zirconia body for dental cutting of FIG. 3 with the impregnation solution.

[0080] As shown in Figs. 3 and 4, the zirconia pre-sintered body 1 for dental cutting is configured in a so-called block shape having a substantially rectangular parallelepiped shape. In the embodiment of Figs. 3 and 4, the impregnating solution is brought into contact with the lower surface 7 of a square shape with one side having a length of s, and the zirconia pre-sintered body 1 is impregnated with the impregnating solution from one contact portion. More specifically, in the embodiment of Figs. 3 and 4, a first imaginary straight line IL1 and a second imaginary straight line IL2 are defined that pass through one vertex V of the lower surface 7 of the square shape and are perpendicular to each other so as to be parallel to two sides forming the vertex V. Then, the impregnating solution is brought into contact with an area with a radius s / 2 from the vertex V as the center, forming a sector-shaped contact portion 3 with a radius s / 2, and the zirconia pre-sintered body 1 is impregnated with the impregnating solution from the sector-shaped contact portion 3 with a radius s / 2.

[0081] Therefore, in the embodiment of FIG. 3 and FIG. 4, a non-contact portion 4 that does not come into contact with the impregnating solution exists on one end side in the extension direction of the first imaginary straight line IL1, and a single contact portion 3 is formed by the impregnating solution coming into contact with the lower surface 7 such that a non-contact portion 4 that does not come into contact with the impregnating solution exists on one end side in the extension direction of the second imaginary straight line IL2.

[0082] In FIG. 4, the impregnation state of the impregnation solution in the cross section of the zirconia pre-sintered body that includes the first virtual straight line IL1 and is perpendicular to the lower surface 7 is shown by a permeated portion 5 where the impregnation solution has permeated and a non-permeated portion 6 where the impregnation solution has not permeated. As shown in FIG. 4, in this embodiment, the impregnation solution permeates the inside of the zirconia pre-sintered body 1 so that the permeation portion 5 has an elliptical arc shape. In this embodiment, the impregnation solution is impregnated into the zirconia pre-sintered body 1 from the contact portion 3 having a sector shape with a radius s / 2 centered on the apex V. Therefore, the impregnation state of the impregnation solution in the cross section of the zirconia pre-sintered body that includes the second virtual straight line IL2 and is perpendicular to the lower surface 7 is the same as the impregnation state of the impregnation solution in the cross section of the zirconia pre-sintered body 1 that includes the first virtual straight line IL1 and is perpendicular to the lower surface 7, as shown in FIG. 4. Therefore, in this embodiment, the permeation portion 5 has a shape obtained by cutting an approximately ellipsoid centered on the apex V into 1 / 8 with the apex V as the center. Thus, in this embodiment as well, the boundary between the permeated portion 5 and the non-permeated portion 6 has at least a partial curved shape in both a cross section of the zirconia pre-sintered body that includes the first imaginary straight line IL1 and is perpendicular to the lower surface 7, and a cross section of the zirconia pre-sintered body that includes the second imaginary straight line IL2 and is perpendicular to the lower surface 7.

[0083] In the above embodiment, the first imaginary straight line IL1 and the second imaginary straight line IL2 are defined so as to pass through one vertex V of the lower surface 7. However, the first imaginary straight line IL1 and the second imaginary straight line IL2 can be defined arbitrarily on the surface layer that comes into contact with the impregnating solution, as long as there is a non-contact portion that does not come into contact with the impregnating solution on at least one side of the first imaginary straight line and there is a non-contact portion that does not come into contact with the impregnating solution on at least one side of the second imaginary straight line.

[0084] In the above embodiment, the first imaginary line IL1 and the second imaginary line IL2 are defined so as to be parallel to the two sides forming the vertex V. However, the first imaginary line IL1 and the second imaginary line IL2 can be defined in any direction as long as there is a non-contact portion that does not come into contact with the impregnation solution on at least one side of the first imaginary line, and there is a non-contact portion that does not come into contact with the impregnation solution on at least one side of the second imaginary line.

[0085] FIG. 5 is a schematic diagram of a surface (contact surface) of a pre-sintered zirconia body for dental cutting according to a third embodiment, which is in contact with an impregnation solution, and FIG. 6 is a schematic diagram of the impregnated state of the pre-sintered zirconia body for dental cutting of FIG. 5 with the impregnation solution.

[0086] As shown in Fig. 5 and Fig. 6, the zirconia pre-sintered body 1 for dental cutting is configured in a so-called disk shape having a substantially circular plate shape. In the embodiment of Fig. 5 and Fig. 6, the impregnation solution is brought into contact with a plurality of parts of the circular upper surface 2, so that the zirconia pre-sintered body 1 is impregnated with the impregnation solution from a plurality of contact parts 3. More specifically, in the embodiment of Fig. 5 and Fig. 6, a first imaginary straight line IL1 and a second imaginary straight line IL2 are defined so as to be perpendicular to each other and pass through a position displaced from the center C of the circular upper surface 2. Then, the impregnation solution is brought into contact with a circle having a radius r1 from the center of the intersection of the first imaginary straight line IL1 and the second imaginary straight line IL2, so that a contact part 3A having a circular shape having a radius r1 is formed. Then, the impregnation solution is brought into contact with the plurality of portions so that a plurality of contact portions 3B are formed at equal intervals on the first imaginary straight line IL1 and the second imaginary straight line IL2 with the contact portion 3A at the center, and another contact portion 3C is formed in a matrix shape together with the contact portions 3A and 3B based on the contact portions 3A and 3B, and the impregnation solution is impregnated into the zirconia pre-sintered body 1 through the plurality of contact portions 3. As shown in Fig. 5, each of the plurality of contact portions 3 has a circular shape and is formed so as not to be in contact with each other. The plurality of contact portions 3 are formed so that the interval between adjacent contact portions 3 is d1.

[0087] Therefore, in the embodiment of FIGS. 5 and 6, the impregnating solution is in contact with the upper surface 2 to form a contact portion 3A such that, centered on the intersection of the first imaginary straight line IL1 and the second imaginary straight line IL2, there are non-contact portions 4 that are not in contact with the impregnating solution on both ends in the extension direction of the first imaginary straight line IL1, and there are non-contact portions 4 that are not in contact with the impregnating solution on both ends in the extension direction of the second imaginary straight line IL2.

[0088] On the first imaginary straight line IL1, non-contact portions 4 that do not come into contact with the impregnating solution exist on both ends in the extension direction of the first imaginary straight line IL1, and the impregnating solution comes into contact with the upper surface 2 so that non-contact portions 4 that do not come into contact with the impregnating solution exist on both ends in a direction parallel to the extension direction of the second imaginary straight line IL2, forming a plurality of contact portions 3B.

[0089] On the second imaginary straight line IL2, there are non-contact portions 4 that do not come into contact with the impregnating solution on both ends in the direction parallel to the extension direction of the first imaginary straight line IL1, and the impregnating solution comes into contact with the upper surface 2 so that there are non-contact portions 4 that do not come into contact with the impregnating solution on both ends in the extension direction of the second imaginary straight line IL2, forming a plurality of contact portions 3B.

[0090] In the region spaced apart from both the first imaginary straight line and the second imaginary straight line, there are non-contact portions 4 that do not come into contact with the impregnating solution on both ends in the direction parallel to the extension direction of the first imaginary straight line IL2, and the impregnating solution comes into contact with the upper surface 2 so that there are non-contact portions 4 that do not come into contact with the impregnating solution on both ends in the direction parallel to the extension direction of the second imaginary straight line IL2, thereby forming a plurality of contact portions 3C.

[0091] 6, the impregnation state of the impregnation solution in the cross section of the zirconia pre-sintered body including the first virtual straight line IL1 and perpendicular to the upper surface 2 is shown by a permeated portion 5 permeated with the impregnation solution and a non-permeated portion 6 not permeated with the impregnation solution. As shown in FIG. 6, in this embodiment, a plurality of permeated portions 5 having a substantially semi-ellipsoid shape are formed at positions corresponding to a plurality of contact portions 3, as in the first embodiment. Thus, in this embodiment, each of the plurality of permeated portions 5 has a boundary with the non-permeated portion 6 at least partially curved shape in both the cross section of the zirconia pre-sintered body including the first virtual straight line IL1 and perpendicular to the upper surface 2 (or a cross section parallel to the cross section) and the cross section of the zirconia pre-sintered body including the second virtual straight line IL2 and perpendicular to the upper surface 2 (or a cross section parallel to the cross section).

[0092] In the embodiment shown in Fig. 1 to Fig. 6, the impregnation solution is brought into contact with the surface (contact surface) of the zirconia pre-sintered body for dental cutting in a horizontal state (the surface is parallel to the horizontal plane). However, as shown in Fig. 7, the impregnation solution may be brought into contact with the surface (contact surface) of the zirconia pre-sintered body for dental cutting in a state in which the impregnation solution is in contact with the surface (contact surface) in a state inclined with respect to the horizontal plane. When the impregnation solution is brought into contact with the surface (contact surface) in a state in which the surface (contact surface) is inclined with respect to the horizontal plane, the three-dimensional curved shape of at least a part of the boundary between the permeation part 5 and the non-permeation part 6 can be made asymmetrical by utilizing the effect of gravity, as shown in Fig. 7. EXAMPLES

[0093] Examples of the present invention will be specifically described below, but the present invention is not limited to these examples.

[0094] [Preparation of pre-sintered zirconia] 17 g of zirconia powder (Zpex: manufactured by Tosoh Corporation) was filled into a die with a diameter of 20 mm and a height of 56 mm, and uniaxially pressed at a pressure of 15 kN to obtain a zirconia molded body. The obtained zirconia molded body was subjected to CIP treatment by pressing at a pressure of 200 MPa for 60 seconds using a cold isostatic press. The zirconia molded body after CIP treatment was pre-sintered at 1000°C for 30 minutes to obtain a pre-sintered zirconia body.

[0095] [Preparation of impregnation solution] Impregnation solutions 1 to 11 were prepared according to Table 1. Each impregnation solution was prepared by putting a solvent, a metal element, and a metal element support material into a PET bottle and mixing them by an upside-down mixing method.

[0096] [Table 1]

[0097] [Metal element loading measurement] The amount of supported metal elements was measured using an X-ray fluorescence analyzer (ZSX100e, manufactured by Rigaku). The impregnated surface of the zirconia pre-sintered body for dental cutting, which had been brought into contact with the impregnation solution, was polished with waterproof abrasive paper, and the surfaces at depths of 1, 4, 5, 6, 9, and 18 mm from the impregnated surface were analyzed to measure the amount of supported metal elements. In this embodiment, the amount of supported metal elements was analyzed using an X-ray fluorescence analyzer, but the amount of supported metal elements in the present invention may be analyzed by other analytical methods such as EDX (energy dispersive X-ray spectroscopy).

[0098] [R-value measurement] After sintering the zirconia pre-sintered body, the area where the metal element was supported was judged from the change in color tone using an optical microscope (VH-ZST, manufactured by KEYENCE Corporation), and the R value of the metal element supported part was calculated in two directions (first direction and second direction) that passed through the center of the circular upper surface, were perpendicular to the circular upper surface, and were perpendicular to each other.

[0099] (Examples 1 to 5) The zirconia pre-sintered body was placed in a jig such that only the circular upper surface was exposed, and then the upper surface was masked with vinyl tape. A hole of Φ1.0 mm was made in the vinyl tape used for masking at a position corresponding to the center of the circular upper surface. A sample in which 0.04 g of each impregnation solution was dropped onto the masked zirconia pre-sintered body and a sample in which 1.0 g of each solution was dropped onto the masked zirconia pre-sintered body were prepared. After that, the sample was left to stand for 1 hour, so that the entire amount of the impregnation solution was permeated into the zirconia pre-sintered body. The zirconia pre-sintered body permeated with the impregnation solution was removed from the jig, placed in a resin bag, and degassed. The degassed zirconia pre-sintered body was placed in a dryer and heat-treated at 97 ° C for 15 hours to precipitate metal compounds. After the heat treatment, the zirconia pre-sintered body was removed from the resin bag and heat-treated in an electric furnace (500 ° C, 30 minutes) to obtain a zirconia pre-sintered body for dental cutting processing. The center of the obtained zirconia pre-sintered body for dental cutting was cut vertically downward from the upper surface so that the dimensions after sintering would be 14.5 mm x 15.0 mm x 1.0 mm, and then sintered at 1450°C for 1 hour.

[0100] Example 6 The zirconia pre-sintered body was placed in a jig such that only the circular upper surface was exposed, and then the upper surface was masked with vinyl tape. A hole of Φ1.0 mm was made in the vinyl tape used for masking at a position corresponding to the center of the circular upper surface. A sample in which 0.04 g of each impregnation solution was dropped onto the masked zirconia pre-sintered body and a sample in which 1.0 g of each solution was dropped onto the masked zirconia pre-sintered body were prepared. After that, the sample was left to stand for 1 hour, so that the entire amount of the impregnation solution was permeated into the zirconia pre-sintered body. The zirconia pre-sintered body permeated with the impregnation solution was removed from the jig, placed in a dryer, and heat-treated at 60 ° C for 10 hours to increase the viscosity of the solvent and cause the metal elements to remain in the zirconia pre-sintered body. After the heat treatment, the zirconia pre-sintered body was heat-treated in an electric furnace (500 ° C, 30 minutes) to obtain a zirconia pre-sintered body for dental cutting processing. The center of the obtained zirconia pre-sintered body for dental cutting was cut vertically downward from the upper surface so that the dimensions after sintering would be 14.5 mm x 15.0 mm x 1.0 mm, and then sintered at 1450°C for 1 hour.

[0101] (Examples 7 to 11) The zirconia pre-sintered body was placed in a jig such that only the circular upper surface was exposed, and then the upper surface was masked with vinyl tape. A hole of Φ1.0 mm was made in the vinyl tape used for masking at a position corresponding to the center of the circular upper surface. A sample in which 0.04 g of each impregnation solution was dropped onto the masked zirconia pre-sintered body and a sample in which 1.0 g of each solution was dropped onto the masked zirconia pre-sintered body were prepared. After that, the sample was left to stand for 1 hour, so that the entire amount of the impregnation solution was permeated into the zirconia pre-sintered body. The zirconia pre-sintered body permeated with the impregnation solution was removed from the jig, placed in a dryer, and dried at 120 ° C for 15 hours. After drying, the zirconia pre-sintered body was heat-treated in an electric furnace (500 ° C, 30 minutes) to obtain a zirconia pre-sintered body for dental cutting processing. The center of the obtained zirconia pre-sintered body for dental cutting was cut vertically downward from the upper surface so that the dimensions after sintering would be 14.5 mm x 15.0 mm x 1.0 mm, and then sintered at 1450°C for 1 hour.

[0102] In Examples 1 to 11, when 0.04 g of each impregnation solution was dropped, the R value after sintering in each of the first direction and the second direction was 0.5 mm to 1.25 mm, respectively, was classified as A, the R value was other than that, and the region where the metal element was supported did not have a macroscopic curved shape was classified as C. In addition, when 1.00 g of each impregnation solution was dropped, the R value after sintering in the range of 0.3 mm to 250 mm was classified as A, the R value was other than that, and the region where the metal element was supported did not have a macroscopic curved shape was classified as C.

[0103] [Table 2]

[0104] In all the examples, it was confirmed that the region in which the metal element was supported had a macroscopic curved shape in each of the first and second directions. When 0.04 g of each impregnation solution was dropped, in Examples 1 to 6 in which the impregnation solution containing the metal element support material was used, the region in which the metal element was supported was supported in the zirconia pre-sintered body while maintaining the curved shape due to the decomposition (Examples 1 to 5) and high viscosity (Example 6) of the metal element support material, and the specified R value was satisfied even after complete sintering. On the other hand, in Examples 7 to 11 in which the impregnation solution not containing the metal element support material was used, the metal element was segregated on the surface of the zirconia pre-sintered body as the solvent evaporated in the drying process of the impregnation solution, and none of them satisfied the R value of 0.3 mm to 250 mm after sintering. When 1.0 g of each impregnation solution was dropped, the prescribed R value was met in all examples. From the above results, it can be seen that the metal support material is effective in cases where the color tone adjustment part is relatively small, such as reproduction of the mamelon part.

[0105] (Examples 12 to 17) The zirconia pre-sintered compact was placed in a jig that exposed only its upper surface, and then the upper surface was masked with vinyl tape. A hole of the size shown in Table 3 was made in the vinyl tape used for masking, at a position corresponding to the center of the circular upper surface. The jig was attached to the masked zirconia pre-sintered compact, and a weight of 0.01 g / mm2 was applied to the area of ​​the hole. 2 Impregnation solution 1 was dripped so that the impregnation solution was 100% and left to stand for 1 hour, so that the entire amount of the impregnation solution was impregnated into the zirconia pre-sintered body. The zirconia pre-sintered body impregnated with the impregnation solution was removed from the jig, placed in a resin bag, and degassed. The degassed zirconia pre-sintered body was placed in a dryer and heat-treated at 97°C for 15 hours to precipitate metal compounds. After the heat treatment, the zirconia pre-sintered body was removed from the resin bag and heat-treated in an electric furnace (500°C, 30 minutes) to obtain a zirconia pre-sintered body for dental cutting. The center of the obtained zirconia pre-sintered body for dental cutting was cut vertically downward from the upper surface so that the dimensions after sintering were 14.5mm x 15.0mm x 1.0mm, and sintered at 1450°C for 1 hour. After sintering, the R value was measured in two mutually perpendicular directions (first direction and second direction) using an optical microscope. The metal element support portion (the portion penetrated by the impregnation solution) was rated as A when its depth from the contact surface was 1.0 mm or more and its R value was 0.5 mm to 30 mm. The coloring component support portion was rated as B when its depth and R value were other than the above. The coloring component support area did not have a macroscopic curved shape.

[0106] [Table 3]

[0107] In all of the examples, it was confirmed that the region carrying the coloring component had a curved shape macroscopically. -4 In Examples 12 to 15, which satisfied the above 1.2, the depth and R value of the metal element support portion were within the specified values. On the other hand, in Example 16, the depth of the metal element support portion was 1.0 mm or more, but the R value was larger than the specified value. In Example 17, the depth of the metal element support portion was 1.0 mm or less.

[0108] (Example 18) The zirconia pre-sintered body was placed in a jig such that only the upper surface was exposed, and then the upper surface was masked with vinyl tape. A hole of Φ1.0 mm was made in the vinyl tape used for masking at a position corresponding to the center of the circular upper surface. A jig was attached to the masked zirconia pre-sintered body, 1.0 g of impregnation solution 1 was dropped, and the zirconia pre-sintered body was allowed to permeate with the entire amount of the impregnation solution by leaving it to stand for 1 hour. The zirconia pre-sintered body permeated with the impregnation solution was removed from the jig, placed in a resin bag, and degassed. The degassed zirconia pre-sintered body was placed in a dryer and heat-treated at 97 ° C for 15 hours to precipitate metal compounds. After the heat treatment, the zirconia pre-sintered body was removed from the resin bag and heat-treated in an electric furnace (500 ° C, 30 minutes) to obtain a zirconia pre-sintered body for dental cutting processing. The impregnated surface of the obtained zirconia pre-sintered body for dental cutting was analyzed from the center (the center of the hole in the vinyl tape) up to 18 mm at 0.5 mm intervals to measure the amount of supported metal element (Fe).

[0109] Comparative Example 1 9 g of colored zirconia raw material powder (ZPEX yellow: manufactured by Tosoh Corporation) was filled into a mold (Φ20 mm, t56 mm) and pressed (surface pressure: 1 kN) to obtain a cylindrical zirconia molded body A. The obtained zirconia molded body A was polished with waterproof abrasive paper (♯240) and molded into a hemispherical ellipsoid. The zirconia molded body A was set again in a mold (Φ20 mm, t56 mm), and zirconia raw material powder (Zpex Smile: manufactured by Tosoh Corporation) was filled on top of it so that the total weight of the molded body A was 17 g, and press molding (surface pressure: 15 kN) was performed to obtain a cylindrical zirconia molded body B. Furthermore, the zirconia molded body B was subjected to CIP treatment (maximum load pressure: 50 MPa, holding time: 1 minute). After that, it was calcined in an electric furnace (1000 °C, 30 minutes) to produce a zirconia pre-sintered body. For the obtained zirconia pre-sintered body, the surface on which the zirconia molded body A was exposed was set as the lower surface, and the lower surface was analyzed from the center up to 18 mm at intervals of 0.5 mm to measure the amount of metal element (Fe).

[0110] [Table 4]

[0111] In Example 18, the weight of the supported Fe decreased with increasing depth from the impregnation surface of the zirconia pre-sintered body for dental cutting. The rate of decrease in the weight of the supported Fe increased with increasing depth from the impregnation surface of the zirconia pre-sintered body for dental cutting. On the other hand, in Comparative Example 1, the weight of Fe was constant regardless of the depth from the lower surface. This shows that Example 18 provides a gradation in color adjustment, and is suitable for reproducing tooth color. In Example 18, Fe was selected as an example of a metal element to be supported, but the gradation of the colored portion can be reproduced in the same way even when other metal elements are supported. [Industrial Applicability]

[0112] According to the present invention, the changes in color shade and intensity in the porous molded body (and / or its sintered body) itself can be made to be closer to those of natural teeth, so that the porous molded body (and / or its sintered body) itself has an appearance closer to that of natural teeth. [Explanation of symbols]

[0113] 1. Zirconia pre-sintered body 2 Top side 3 Contact area 4 Non-contact part 5 Penetration part 6 Non-permeable area

Claims

1. A method for impregnating a porous body for dental cutting with an impregnation solution containing a metal element and a solvent, comprising: A contacting step includes contacting at least one surface of a porous molded body for dental cutting with an impregnation solution containing a metal element and a solvent to form one or more contact portions, When a first virtual line and a second virtual line perpendicular to the first virtual line are defined on a surface that comes into contact with the impregnation solution, In the contacting step, A method for forming one or more contact portions by contacting the impregnating solution such that a non-contact portion that is not in contact with the impregnating solution exists on at least one side of a first virtual straight line, and a non-contact portion that is not in contact with the impregnating solution exists on at least one side of a second virtual straight line.

2. The area ratio of the contact area to the non-contact area on the surface layer that comes into contact with the impregnation solution is 5.0 × 10 －４ 2. The method of claim 1, wherein the impregnation solution is contacted such that .about.1.

2.

3. The amount of impregnation solution per contact part is 0.01 g / mm ２ The method of claim 1, wherein

4. 2. The method according to claim 1, wherein in the contacting step, the impregnation solution is contacted such that the impregnation solution does not permeate the entire porous molded body for dental cutting.

5. 2. The method according to claim 1, wherein the metal element contained in the impregnation solution is at least one selected from the group consisting of rare earth metal elements and transition metal elements.

6. 2. The method of claim 1, wherein the metal element contained in the impregnation solution is one or more selected from the group consisting of yttrium, calcium, cerium, terbium, nickel, iron, erbium, cobalt, niobium, titanium, praseodymium, zirconium, vanadium, niobium, tantalum and chromium.

7. 2. The method according to claim 1, wherein the impregnation solution contains at least one metal element-carrying material for carrying a metal element on the porous molded body for dental cutting.

8. 8. The method of claim 7, wherein the metal element support material is an organic compound.

9. 8. The method according to claim 7, wherein the metal element-supporting material is at least one selected from the group consisting of oxycarboxylic acids, glycols, and combinations thereof.

10. 2. The method of claim 1, wherein the contact portion is circular or elliptical in shape.

11. The method according to claim 10, wherein the diameter or major axis of the contact portion is 0.5 to 15 mm.

12. 2. The method of claim 1, wherein in the contacting step, the contact area is defined by a masking material.

13. 2. The method according to claim 1, wherein the impregnating solution penetrates from the center of the contact portion to a depth of 1.0 mm or more in a direction perpendicular to the surface with which the impregnating solution contacts.

14. 2. The method according to claim 1, wherein the impregnating solution is brought into contact with the porous molded body for dental cutting such that the impregnated area of ​​the impregnating solution has a curve with an R value of 0.3 mm to 250 mm inside the porous molded body for dental cutting.

15. 2. The method according to claim 1, wherein the porous compact for dental cutting is a pre-sintered zirconia compact for dental cutting.

16. A method for supporting a metal element on a porous molded body for dental cutting, comprising the steps of: a contacting step of contacting at least one surface of the porous molded body for dental cutting with an impregnation solution containing a metal element, a solvent, and a metal element support to form one or more contact portions; A supporting step of supporting the metal element contained in the impregnation solution on the porous body for dental cutting processing, When a first virtual line and a second virtual line perpendicular to the first virtual line are defined on a surface that comes into contact with the impregnation solution, In the contacting step, the impregnation solution is A non-contact portion that is not in contact with the impregnation solution is present on at least one side of the first virtual line, and A method for forming one or more contact portions such that a non-contact portion that is not in contact with the impregnation solution exists on at least one side of the second imaginary straight line.

17. 17. The method according to claim 16, wherein in the supporting step, the metal element in the impregnation solution is supported on the porous body by heating at a temperature not exceeding the boiling point of the solvent in the impregnation solution.

18. The method according to claim 16, wherein in the supporting step, the metal element in the impregnation solution is supported on the porous body by heating at a temperature of 50 to 170°C.

19. The method of claim 16, wherein the metal element support material is an organic compound.

20. The method according to claim 16, wherein the metal element-supporting material is at least one selected from the group consisting of oxycarboxylic acids, glycols, and combinations thereof.

21. The method of claim 16, wherein the porous compact for dental cutting is a presintered zirconia compact for dental cutting.

22. A method for producing a dental sintered body, comprising sintering a porous molded body for dental cutting impregnated with an impregnation solution by any one of the methods of claims 1 to 15, or a porous molded body for dental cutting carrying a metal element by any one of the methods of claims 16 to 21.

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