Nonlinearly-color-adjusted porous molding for dental cutting

Abstract

To provide a porous molding (and / or a sintered body thereof) with an external appearance close to that of a natural tooth by making changes in color shading and intensity of the porous molding (and / or the sintered body thereof) itself close to those of the natural tooth.SOLUTION: A porous molding for dental cutting includes a first area where a concentration of at least one of supported metal elements is within a certain range; and a second area that is adjacent to the first area and where the concentration of the supported metal element decreases as it moves away from the first area. At least a part of an interface between the first area and the second area has a three-dimensional curved surface shape.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a color-adjusted porous molded body for dental cutting, and more specifically to a color-adjusted porous molded body for dental cutting for producing dental restorations using CAD / CAM. [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, to improve the aesthetics of 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 (particularly color and translucency) of natural teeth using zirconia (sintered body) itself. Patent Document 1 discloses a blank in which an ivory-colored material with low light translucency is disposed inside the blank, and a material with high light translucency (a material equivalent to enamel) is disposed so as to surround the material. 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, these conventional blanks are 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 natural teeth. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2014-534018 [Patent Document 2] International Publication No. 2019 / 131787 Summary of the Invention [Problem to be solved by the invention]

[0006] Conventional colored porous bodies are composed of parallel layers colored in tooth color, so the porous body (and / or its sintered body) itself could not 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 / or its sintered body) itself to have an appearance closer to that of natural teeth.

[0007] As a result of intensive research into the porous molded body for dental cutting, it was found that three-dimensionally changing the concentration of the metal element carried by the porous molded body for dental cutting is effective in making the color shade and intensity of the porous molded body (and / or its sintered body) more similar to that of natural teeth, and thus making the porous molded body (and / or its sintered body) itself have an appearance more similar to that of natural teeth. The details of the present invention are described below. [Means for solving the problem]

[0008] The present invention provides a porous molding for dental cutting processing carrying a metal element, the porous molding having a first region in which the concentration of at least one of the carried metal elements is within a certain range, and a second region adjacent to the first region and in which the concentration of the carried metal element decreases with increasing distance from the first region, and at least a portion of the interface between the first region and the second region has a three-dimensional curved shape.

[0009] The present invention also provides a porous molding for dental cutting processing carrying a metal element, the porous molding for dental cutting processing having a first region in which the concentration of at least one of the carried metal elements is within a certain range, and a second region adjacent to the first region and having a portion in which the concentration of the carried metal element decreases three-dimensionally with increasing distance from the first region.

[0010] The present invention also provides a porous molding for dental cutting processing carrying a metal element, the porous molding having a first region in which the concentration of at least one of the carried metal elements is within a certain range, and a second region adjacent to the first region and in which the concentration of the carried metal element decreases with increasing distance from the first region, the second region having portions in which the concentration of the carried metal element decreases along three linear directions that are mutually perpendicular in the first region.

[0011] The present invention also provides a sintered body obtained by sintering the porous molded body for dental cutting of the present invention after cutting. Effect of the Invention

[0012] 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]

[0013] [Figure 1] FIG. 2 is a diagram showing the concentration of supported metal elements in the central cross section of the zirconia pre-sintered body for dental cutting according to the first embodiment. [Diagram 2] 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 3] FIG. 11 is a schematic diagram showing the concentration of metal elements supported on the side surface of the zirconia pre-sintered body for dental cutting according to the second embodiment. [Figure 4]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. [Diagram 5] FIG. 13 is a diagram showing the concentration of supported metal elements in a zirconia pre-sintered body for dental cutting according to the third embodiment. [Figure 6] 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 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. [Figure 8] FIG. 13 shows data on the shape of a single anterior crown for a zirconia pre-sintered body for dental cutting in Example 2. [Figure 9] FIG. 13 shows data on the shape of a single anterior crown for a zirconia pre-sintered body for dental cutting in Comparative Example 2. [Figure 10] FIG. 13 shows data on the shape of a single anterior crown for a zirconia pre-sintered body for dental cutting in Comparative Example 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] In the present invention, the first region may be in the shape of a hemispheroid or a hemisphere.

[0015] In the present invention, the outline of the first region may have a flat portion.

[0016] In the present invention, the outer shape of the first region can have flat portions and three-dimensional curved surface portions connecting the flat portions.

[0017] In the present invention, the outer shape of the first region can have a flat surface portion, a three-dimensional curved surface portion, and a connection portion that connects the flat surface portion and the three-dimensional curved surface portion.

[0018] In the present invention, the second region may have a portion in which the rate of decrease in the concentration of at least one of the supported metal elements is within a certain range.

[0019] In the present invention, the second region may have a portion in which the rate of decrease in the concentration of at least one of the supported metal elements increases with increasing distance from the first region.

[0020] In the present invention, the contour of the first region can have three planar portions.

[0021] In the present invention, the outer shape of the first region can have three planar portions and a three-dimensional curved surface portion connecting the three planar portions.

[0022] In the present invention, the metal element can be selected from the group consisting of rare earth metal elements and transition metal elements.

[0023] In the present invention, the metal element may include one or more metal elements selected from the group consisting of yttrium, calcium, cerium, terbium, nickel, iron, erbium, cobalt, niobium, titanium, praseodymium, zirconium, vanadium, niobium, tantalum, and chromium.

[0024] In the present invention, the metal element may be supported on the porous molded article for dental cutting by a metal element support material.

[0025] Dental restorations obtained from the sintered porous molding for dental cutting of the present invention are excellent in aesthetics, have high color reproducibility, and can reproduce the dentin shape of the mamelon part, 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.

[0026] Hereinafter, one embodiment of the present invention will be specifically described. [Porous compact before metal element loading] The porous compact of the present invention is a porous compact carrying a metal element. The porous compact before carrying the metal element can be, for example, a pre-sintered zirconia body containing zirconia and a stabilizing material for suppressing the phase transition of zirconia. The stabilizing material is not particularly limited, but examples thereof include yttria, ceria, calcia, magnesia, etc.

[0027] In the present invention, the crystal phase of the pre-sintered zirconia before the metal element is supported is preferably tetragonal and / or cubic. If the crystal phase is monoclinic, sufficient translucency may not be imparted after the zirconia is completely sintered, which is not preferable.

[0028] The method for producing the zirconia pre-sintered body of the present invention before the metal element is supported is not particularly limited, and any known production method can be used without any problem. Specifically, it is preferable that the zirconia pre-sintered body is produced by pressure molding zirconia powder and calcining the obtained zirconia molded body. There is no particular limit to the method for producing the zirconia powder used in the zirconia pre-sintered body before the metal element is supported, 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.

[0029] The zirconia powder used in the manufacture of the zirconia pre-sintered body before the metal element is supported in 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 mentioned. 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 before the metal element is supported in the present invention may not contain a coloring agent.

[0030] The zirconia powder used in the production of the pre-sintered zirconia body before supporting a metal element in the present invention may contain a sintering aid, examples of which include alumina and silica.

[0031] The primary particle size of the zirconia powder used in the production of the zirconia pre-sintered body before the metal element is supported 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.

[0032] 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.

[0033] 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.

[0034] By calcining the zirconia molded body, a pre-sintered zirconia body before metal elements are supported 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, and the particles are provided with continuous pores through which a solution can penetrate.

[0035] The calcination temperature of the zirconia pre-sintered body as the porous molded body before supporting the metal element 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 become too low, and chipping or fracture tends to occur easily during cutting. On the other hand, if the calcination temperature is 1200° C. or more, the Vickers hardness and / or bending strength become too high, and the milling bur of the cutting machine becomes worn out rapidly, and the running cost tends to increase.

[0036] The relative density of the zirconia pre-sintered body as a porous molded body before metal elements are supported thereon is preferably 40 to 70%, more preferably 45 to 65%, and particularly preferably 50 to 60%, of the density of the fully sintered zirconia sintered body.

[0037] 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 method for producing these porous molded bodies is not particularly limited, and they may be produced by the same method as the method for producing the above-mentioned zirconia pre-sintered body, or may be produced 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.

[0038] [Metallic elements] Metal elements 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 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.

[0039] The metal element may be directly supported on the porous body, or may be indirectly supported on the porous body, for example, via a metal element support material. The metal element support material is used for the purpose of supporting the metal element in the porous body.

[0040] The term "support" as used herein means, for example, permeating a solution containing a metal element into a porous body and precipitating and sedimenting the metal element within the porous body. It also includes increasing the viscosity of a solution containing a metal element to cause the metal element to remain within the porous body.

[0041] Next, an example of a specific embodiment of the porous molded body for dental cutting of the present invention will be described with reference to the drawings. Fig. 1 is a diagram showing the concentration of supported metal elements in the central cross section of a pre-sintered zirconia body for dental cutting as a porous molded body for dental cutting according to the first embodiment. Fig. 2 is a diagram showing the surface layer (contact surface) of the pre-sintered zirconia body for dental cutting according to this embodiment, which is in contact with the impregnation solution.

[0042] The zirconia pre-sintered body 1 for dental cutting in Fig. 1 is configured in a so-called block shape having a substantially rectangular parallelepiped shape. Fig. 1 shows the concentration of the supported metal element in a cross section passing through the center C of the substantially square upper surface 2 shown in Fig. 2 and perpendicular to the upper surface 2. In the zirconia pre-sintered body for dental cutting according to the first embodiment shown in Fig. 1, the concentration of the supported metal element in a cross section passing through the center C of the substantially square upper surface 2 and perpendicular to the upper surface 2 and the cross section shown in Fig. 1 is substantially the same as the concentration of the supported metal element in the cross section shown in Fig. 1.

[0043] In the embodiment of FIG. 1, the zirconia pre-sintered body for dental cutting 1 has a supported portion 3 on which a metal element is supported, and a non-supported portion 4 on which no metal element is supported. In the embodiment of FIG. 1, yttrium, which is a transition metal element, is supported in the supported portion 3 as the metal element. As shown in FIG. 1, the supported portion 3 has a first region 3A in which the concentration of yttrium is within a certain range, and a second region 3B adjacent to the first region 3A and in which the concentration of supported yttrium decreases with increasing distance from the first region 3A. In the present invention, "concentration within a certain range" is defined by the following method.

[0044] The imaginary perpendicular line VL is the line where the length of the support is maximum in the direction perpendicular to the surface (contact surface) that comes into contact with the impregnation solution. The surface (contact surface) on VL that comes into contact with the impregnation solution is the origin O (0 mm). On the imaginary perpendicular line VL2 on VL that does not include a 0.5 mm interval in the direction away from the origin O (0 mm), the measurement points of the metal element concentration measured at 0.5 mm intervals in the direction away from the origin O from one end of the imaginary perpendicular line VL2 on the origin O side are sequentially designated as P. 1 , P 2 , P 3 P n (n≧5, P n is the first measurement point where no metal element support due to impregnation is measured), and the metal element concentration at each measurement point is C 1 , C 2 , C 3 ···C n Then, the allowable metal element concentration range W, which means that the range of increase or decrease in the metal element concentration is constant, is calculated using the formula 1 below.

number

[0045] Next, P 1 The average concentration value of the metal element concentration C of two consecutive points is calculated in order up to the n-th measurement point.

number

[0046] Furthermore, the average concentration shift value CMA, which is the difference between the average concentration values ​​of two consecutive metal elements, is calculated by the following formula 3: n is calculated for all measurement points up to the nth measurement point.

number

[0047] Average concentration shift value CMA n Compare the value of with the allowable metal element concentration range W, 1 From P n Heading in the direction of the CMA for the first time n The measurement point just before the measurement point W is measurement point P m And this measurement point P m The measurement points from the origin O to the measurement point P m The measurement points up to P m From P n The measurement points up to are the second area.

[0048] The second region may have a portion in which the rate of decrease in the concentration of at least one of the supported metal elements is within a certain range. In the present invention, the "rate of decrease in the concentration is within a certain range" means that P m From P n At the measurement points up to , two consecutive measurement points (P l , P l+1 ) metal element concentration (C l , C l+1 ) and the slope obtained from the next two consecutive measurement points (P l+1 , P l+2 ) metal element concentration (C l+1 , C l+2 ) means the range of measurement points where the absolute value of the difference in slope obtained from the above equation (see equation 4 below) is 1.0 or less.

number

[0049] The second region may have a portion in which the rate of decrease in the concentration of at least one of the supported metal elements increases with increasing distance from the first region. In the present invention, the term "the rate of decrease in the concentration increases with increasing distance from the first region" refers to a region in which the concentration of at least one of the supported metal elements increases with increasing distance from the first region. m From P n At the measurement points up to the origin O, the two consecutive measurement points (P l , P l+1 ) metal element concentration (C l , C l+1 ) is the absolute value of the slope obtained from the next two consecutive measurement points (P l+1 , P l+2 ) metal element concentration (C l+1 , C l+2 ) is smaller than the absolute value of the slope obtained from the above equation. In the present invention, the portion corresponding to both the "portion in which the rate of decrease in the concentration of at least one of the supported metal elements is within a certain range" and the "portion in which the rate of decrease in the concentration of at least one of the supported metal elements increases with increasing distance from the first region" as defined in the present specification belongs to the "portion in which the rate of decrease in the concentration of at least one of the supported metal elements is within a certain range". For example, the second portion of the present invention may have a portion corresponding only to the "portion in which the rate of decrease in the concentration of at least one of the supported metal elements is within a certain range", a portion corresponding to both the "portion in which the rate of decrease in the concentration of at least one of the supported metal elements is within a certain range" and the "portion in which the rate of decrease in the concentration of at least one of the supported metal elements increases with increasing distance from the first region", and a portion corresponding only to the "portion in which the rate of decrease in the concentration of at least one of the supported metal elements increases with increasing distance from the first region".

number

[0050] 1, the support 3 of this embodiment has a semi-elliptical shape in two cross sections that pass through the center C of the substantially square upper surface 2 and are perpendicular to each other. Therefore, the support 3 of this embodiment has a substantially semi-elliptical shape as a whole. Thus, in this embodiment, at least a part of the interface between the support 3 and the non-support 4 has a three-dimensional curved shape.

[0051] In addition, the first region 3A of this embodiment has a semi-elliptical shape in two cross sections that pass through the center C of the substantially square upper surface 2 and are perpendicular to each other. Therefore, the first region 3A of this embodiment has a substantially semi-elliptical shape as a whole. Thus, in this embodiment, at least a part of the interface between the first region 3A and the second region 3B has a three-dimensional curved shape.

[0052] Thus, in this embodiment, at least a part of the interface between the first region 3A and the second region 3B has a three-dimensional curved shape. In other words, the second region 3B of this embodiment has a part where the concentration of the supported metal element decreases three-dimensionally as it moves away from the first region. In other words, in this embodiment, the first region has a part where the concentration of the supported metal element decreases along three mutually orthogonal linear directions (X direction and Y direction in FIG. 1 and directions perpendicular to the X direction and Y direction). Therefore, the zirconia sintered body for dental cutting obtained by sintering the zirconia pre-sintered body for dental cutting 1 has a part where the gradation of ... Therefore, the changes in color shade and intensity in the sintered body itself can be made to be closer to those of natural teeth, so that the zirconia sintered body for dental cutting processing itself has an appearance closer to that of natural teeth.

[0053] In this embodiment, at least a part of the interface between the supported portion 3 and the non-supported portion 4 has a three-dimensional curved surface 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 obtained by sintering the zirconia pre-sintered body for dental cutting 1. Therefore, the color shade and intensity of the sintered body itself can be made to be closer to that of natural teeth, so that the zirconia sintered body for dental cutting itself can have an appearance closer to that of natural teeth.

[0054] Next, an example of a method for producing the zirconia pre-sintered body for dental cutting 1 of this embodiment will be described. The zirconia pre-sintered body for dental cutting 1 of this embodiment can be produced, for example, by impregnating the zirconia pre-sintered body for dental cutting before the metal element is supported thereon with an impregnation solution containing the metal element and a solvent.

[0055] The impregnation solution that can be used for producing the pre-sintered zirconia body for dental cutting 1 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.

[0056] The impregnation solution preparation step is a step of 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, stirring with a glass rod or the like, stirring by rotating 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 stirring with an ultrasonic homogenizer can be mentioned.

[0057] There is no particular limit to the metal ion concentration of the impregnation solution, but for example, in the case of yttrium ions, it is preferably about 2.0wt% to 10.0wt%. If it is 2.0wt% or less, the amount of yttrium supported on the zirconia pre-sintered body for dental cutting as a porous body is small, and sufficient properties may not be obtained. If it is 10.0wt% or more, the amount of yttrium supported on the zirconia pre-sintered body for dental cutting as a porous body 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 properties, 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.

[0058] The impregnation solution may contain an acid, a base, or a pH adjuster 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 as the porous molded body.

[0059] A specific example of a method for supporting a metal element using the above-mentioned impregnation solution includes a method including a contact step, a permeation step, and a supporting step.

[0060] [Contact process] The contact step is a step of bringing the impregnation solution into contact with the surface of the zirconia pre-sintered body as a porous compact. The method of bringing the impregnation solution into contact with the surface of the zirconia pre-sintered body is not particularly limited, but examples of the method include dripping the impregnation solution onto the zirconia pre-sintered body or painting the surface of the zirconia pre-sintered body with a brush.

[0061] The surface of the zirconia pre-sintered body refers to all surfaces exposed to the atmosphere. For example, in the case of a rectangular zirconia pre-sintered body, all six surfaces exposed to the atmosphere are surface surfaces, and in the case of a cylindrical zirconia pre-sintered body, all three surfaces, the side surface corresponding to the circumference and the upper and lower surfaces forming a circle, are surface surfaces. In the contacting step of this embodiment, at least one surface of the zirconia pre-sintered body for dental cutting as a porous molded body is contacted with an impregnation solution containing a metal element and a solvent to form one or more contact parts.

[0062] As a specific embodiment of the contact of the impregnation solution, when a first virtual line and a second virtual line perpendicular to the first virtual line are defined on the surface surface with which the impregnation solution comes into contact, the impregnation solution is contacted to form one or more contact portions such that there is a non-contact portion on at least one side of the first virtual line that the impregnation solution does not come into contact with, and there is a non-contact portion on at least one side of the second virtual line that the impregnation solution does not come into contact with. For example, the contact portion and the non-contact portion can be formed by coating or masking a part of the surface surface of the zirconia pre-sintered body as the porous compact 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 contacted only with a part of the surface surface of the zirconia pre-sintered body as the porous compact by coating, dripping, or the like, without coating or masking.

[0063] 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.

[0064] 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 In addition, when a plurality of contact portions are formed, the above-mentioned area ratio is calculated based on the total area of ​​the plurality of contact portions, and the area ratio is preferably 5.0×10 to 0.05. -4 The impregnation solution is contacted so that the pH is 1.2.

[0065] The contact surface is the surface layer of the zirconia pre-sintered body as a porous compact where there is a contact portion. For example, in a cylindrical zirconia pre-sintered body, the circumferential surface is the side surface, and the circular surfaces are the top and bottom surfaces. When the top surface is brought into contact with the impregnation solution, only the top surface becomes the contact surface. When the top and bottom surfaces are brought into contact with the impregnation solution, both the top and bottom surfaces become the contact surfaces.

[0066] 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 the thickness is less than this, the color tone adjustment portion (for example, the metal element carrying 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 pre-sintered zirconia body.

[0067] [Infiltration process] In the infiltration step, the impregnation solution that has been brought into contact with the zirconia pre-sintered body as a porous body in the contact step is infiltrated into the zirconia pre-sintered body. There is no particular limitation on the infiltration method, and various methods such as leaving the zirconia pre-sintered body in an air atmosphere or infiltration under pressure or reduced pressure may be used.

[0068] The infiltration step is preferably carried out until the contacted impregnation solution is fully infiltrated into the zirconia pre-sintered body as a porous molded body. In the infiltration step of the impregnation solution, 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 contacted impregnation solution is fully infiltrated into the zirconia pre-sintered body in the infiltration step, the supporting step described below is preferably carried out 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 zirconia pre-sintered 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 a 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.

[0069] [Supporting process] In the carrying step, the metal element carrying 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 zirconia pre-sintered body as a porous molded body. The temperature of the heat treatment in the carrying step can be set according to the metal element carrying 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 carrying 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.

[0070] In the supporting step, the metal element supporting portion that supports the metal element in the zirconia pre-sintered body as the porous molded body preferably has a shape including a curve inside the zirconia pre-sintered body. In this specification, in order to quantify the magnitude of the curve, the R value calculated by the following formula is used.

number

[0071] Since the zirconia pre-sintered body as the porous molded body after the supporting step may contain solvent, unreacted materials, by-products, etc., 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 zirconia pre-sintered body as 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 materials, by-products, etc. These heat treatments can remove impurities, organic matter, and odors.

[0072] In this way, a zirconia pre-sintered body for dental cutting, i.e., a porous molded body for dental cutting, is obtained. The obtained porous molded body for dental cutting is preferably cut to a desired size, cut, and surface polished as necessary.

[0073] There is no particular restriction on the type of prosthetic device to be cut using the porous molded body for dental cutting, 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 from which the prosthetic device is produced 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.

[0074] By completely sintering the porous green body for dental cutting, a sintered porous green body for dental cutting is obtained.

[0075] 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.

[0076] The relative density of the porous molding 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.

[0077] FIG. 2 is a schematic diagram of a surface layer surface (contact surface) of a pre-sintered zirconia body for dental cutting as a porous molded body according to this embodiment, which is in contact with an impregnation solution.

[0078] In this embodiment, 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, each side of which has a 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 circular contact portion 5 having a radius of r / 4, and the zirconia pre-sintered body 1 is impregnated with the impregnation solution from this circular contact portion 5 having a radius of r / 4.

[0079] Therefore, in the embodiment of FIG. 2, the impregnating solution comes into contact with the upper surface 2 to form one contact portion 5 such that there are non-contact portions 6 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 6 that do not come into contact with the impregnating solution on both ends in the extension direction of the second imaginary straight line IL2.

[0080] As shown in FIG. 1, in this embodiment, the impregnation solution permeates the zirconia pre-sintered body 1 as a porous compact so that the support portion 3 has a semi-elliptical shape. In this embodiment, the impregnation solution permeates the zirconia pre-sintered body 1 so that the first region 3A 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 in the zirconia pre-sintered body 1 from the contact position at the contact portion 5. In this embodiment, the impregnation solution is impregnated into the zirconia pre-sintered body 1 from the contact portion 5 having a circular shape with a center radius of r / 4 formed on the approximately square upper surface 2. Therefore, the shapes of the support portion 3 and the first region 3A in the cross section of the zirconia pre-sintered body that includes the second virtual straight line IL2 and is perpendicular to the upper surface 2 are the same as the shapes of the support portion 3 and the first region 3A in the cross section of the zirconia pre-sintered body 1 that includes the first virtual straight line IL1 and is perpendicular to the upper surface 2, as shown in FIG. 1. Therefore, in this embodiment, the support 3 and the first region 3A have a substantially semi-ellipsoidal shape. By using this method, it is possible to manufacture a zirconia pre-sintered body for dental cutting, i.e., a porous compact, in which at least a part of the interface between the first region 3A and the second region 3B has a three-dimensional curved shape, as shown in FIG.

[0081] Fig. 3 is a diagram showing the concentration of metal elements supported on the side of the pre-sintered zirconia for dental cutting as the porous molded body for dental cutting according to the second embodiment. Fig. 4 is a diagram showing the surface layer surface (contact surface) of the pre-sintered zirconia for dental cutting according to the second embodiment that comes into contact with the impregnation solution.

[0082] As shown in Fig. 4, the zirconia pre-sintered body 1 for dental cutting is configured in a so-called block shape having a substantially rectangular parallelepiped shape. Fig. 3 shows the concentration of the supported metal element on a side surface that passes through one vertex V of the substantially square lower surface 7 and is perpendicular to the lower surface 7. In the zirconia pre-sintered body for dental cutting according to the second embodiment shown in Fig. 3, the concentration of the supported metal element on a side surface that passes through one vertex V of the square lower surface 7 and is perpendicular to the lower surface 7 and the side surface shown in Fig. 3 is the same as the concentration of the supported metal element on the cross section shown in Fig. 3.

[0083] 3, the support 3 of this embodiment has a shape obtained by cutting an ellipse into 1 / 4 along its major and minor axes at two mutually orthogonal side surfaces passing through the vertex V. Therefore, the support 3 of this embodiment has an overall shape obtained by equally dividing an ellipsoid into 1 / 8. Thus, in this embodiment, at least a part of the interface between the support 3 and the non-support 4 has a three-dimensional curved shape.

[0084] Moreover, the first region 3A of this embodiment has a shape obtained by cutting an ellipse into 1 / 4 along its major and minor axes at two mutually perpendicular side surfaces that pass through the vertex V. Therefore, the first region 3A of this embodiment as a whole has a shape obtained by equally dividing an ellipsoid into 1 / 8. Thus, in this embodiment, at least a part of the interface between the first region 3A and the second region 3B has a three-dimensional curved surface shape.

[0085] In this manner, also in this embodiment, at least a part of the interface between the first region 3A and the second region 3B has a three-dimensional curved shape. Therefore, also in this embodiment, at least a part of the interface between the supported portion 3 and the non-supported portion 4 has a three-dimensional curved shape. Therefore, the color shading and intensity of the sintered body itself can be made to be closer to that of natural teeth, and the zirconia sintered body for dental cutting itself can have an appearance closer to that of natural teeth.

[0086] In this embodiment, the impregnating solution is brought into contact with the square lower surface 7 with one side having a length of s, and the impregnating solution is impregnated into the zirconia pre-sintered body 1 as a porous molded body for dental cutting processing from one contact portion 5. 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 square lower surface 7 and are perpendicular to each other so as to be parallel to the two sides forming the vertex V. Then, the impregnating solution is brought into contact with an area with a radius of s / 2 from the vertex V as the center to form a contact portion 3 having a sector shape with a radius of s / 2, and the impregnating solution is impregnated into the zirconia pre-sintered body 1 from the contact portion 5 of the sector shape with a radius of s / 2.

[0087] Thus, the outline of the first region in this embodiment has three planar portions formed by two side surfaces that pass through vertex V and are perpendicular to each other, and a square-shaped bottom surface 7, and a three-dimensional curved portion connecting the three planar portions.

[0088] Fig. 5 is a schematic diagram of the impregnated state of the zirconia pre-sintered body for dental cutting according to the third embodiment, and Fig. 6 is a schematic diagram of the surface layer surface (contact surface) of the zirconia pre-sintered body for dental cutting according to the third embodiment, which is in contact with the impregnating solution.

[0089] As shown in 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. Fig. 5 shows the concentration of the supported metal element at a position displaced from the center C of the circular upper surface 2.

[0090] 5, in this embodiment, a plurality of supported portions 3 each having a substantially semi-ellipsoid shape are formed as in the first embodiment. Thus, in this embodiment, at least a part of the interface between the supported portion 3 and the non-supported portion 4 has a three-dimensional curved shape.

[0091] In addition, the first region 3A of this embodiment has a semi-elliptical shape in two cross sections perpendicular to each other about a position displaced from the center C of the circular upper surface 2, similar to the first embodiment. Therefore, the first region 3A of this embodiment has a substantially semi-elliptical shape as a whole. Thus, in this embodiment, at least a part of the interface between the first region 3A and the second region 3B has a three-dimensional curved shape.

[0092] In this manner, also in this embodiment, at least a part of the interface between the first region 3A and the second region 3B has a three-dimensional curved shape. Therefore, also in this embodiment, at least a part of the interface between the supported portion 3 and the non-supported portion 4 has a three-dimensional curved shape. Therefore, the color shading and intensity of the sintered body itself can be made to be closer to that of natural teeth, and the zirconia sintered body for dental cutting itself can have an appearance closer to that of natural teeth.

[0093] FIG. 6 is a schematic diagram of a surface layer surface (contact surface) of a pre-sintered zirconia body for dental cutting according to the third embodiment, which surface comes into contact with an impregnation solution.

[0094] In this embodiment, a first imaginary straight line IL1 and a second imaginary straight line IL2 are defined so as to intersect at right angles with each other and pass through a position displaced from the center C of the circular upper surface 2. Then, the impregnating solution is brought into contact with the 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 to form a circular contact portion 5A having a radius r1. Then, the impregnating solution is brought into contact with the plurality of portions so that a plurality of contact portions 5B are formed at equal intervals on the first imaginary straight line IL1 and the second imaginary straight line IL2 with the contact portion 5A as the center, and another contact portion 5C is formed in a matrix shape together with the contact portions 5A and 5B based on the contact portions 5A and 5B, and the zirconia pre-sintered body 1 is impregnated with the impregnating solution from the plurality of contact portions 5. As shown in FIG. 6, the plurality of contact portions 5 each have a circular shape and are formed so as not to contact each other. The plurality of contact portions 5 are formed so that the interval between adjacent contact portions 5 is d1.

[0095] In the above embodiment, the entire interface between the first region 3A and the second region 3B has a three-dimensional curved shape. However, the interface between the first region 3A and the second region 3B may have a plane and / or a curved surface other than a three-dimensional curved surface in part. In the above embodiment, the first region has a semi-ellipsoidal shape, but the shape of the first region can be a semi-hemispherical shape, or a shape other than an ellipsoidal shape and a hemispherical shape. In the above embodiment, the outer shape of the first region is composed of a plane portion and a three-dimensional curved portion connecting the plane portion, but the outer shape of the first region can include a portion other than the plane portion and the three-dimensional curved portion.

[0096] In the embodiment shown in Fig. 1 to Fig. 6, the impregnating 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 impregnating 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 impregnating solution is in contact with the surface (contact surface) in a state inclined with respect to the horizontal plane. When the impregnating 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 first region 3A and the second region 3B can be made asymmetrical by utilizing the effect of gravity, as shown in Fig. 7. EXAMPLES

[0097] Examples of the present invention will be specifically described below, but the present invention is not limited to these examples.

[0098] [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.

[0099] [Preparation of impregnation solution] Impregnation solution 1 was prepared according to Table 1. The impregnation solution was prepared by putting the solvent, metal element, and metal element support material into a PET bottle and mixing them by an upside-down mixing method.

[0100] [Table 1]

[0101] [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).

[0102] Example 1 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. The masked zirconia pre-sintered body was attached to the jig, 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) to 18 mm at intervals of 0.5 mm to measure the amount of supported metal element (Fe).

[0103] 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).

[0104] [Table 2]

[0105] Example 2 The zirconia pre-sintered body was placed in a jig so 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 sample was prepared by dropping 1.0 g of impregnation solution 1 onto the masked zirconia pre-sintered body. After that, it was 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 (500 ° C, 30 minutes) in an electric furnace to obtain a zirconia pre-sintered body for dental cutting processing. The data of the anterior single crown shape was arranged on the obtained zirconia pre-sintered body for dental cutting processing as shown in Figure 8. Specifically, because natural teeth have a three-dimensional gradation of color tone from the cervical area to the incisal area, the structure of this natural tooth was taken into consideration and the area was arranged so that the cervical area was area 3A, the middle area was area 3B, and the incisal area was the non-supported area. Based on the arrangement data, a model of a single anterior crown shape was created using a cutting machine (DWX-52DCi, manufactured by Roland DG). The created single crown model was sintered at 1450℃ for 2 hours.

[0106] Comparative Example 2 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. The data for the shape of a single anterior crown was arranged on the obtained zirconia pre-sintered body as shown in Figure 9. Specifically, because natural teeth have a three-dimensional color tone gradation from the cervical part to the incisal edge, the structure of this natural tooth was taken into consideration and the data was arranged so that the cervical part was molded body A and the incisal edge was molded body B. Based on the arranged data, a model of the shape of a single anterior crown was produced using a cutting machine (DWX-52DCi, manufactured by Roland DG Corporation). The produced single crown model was sintered at 1450℃ for 2 hours.

[0107] Comparative Example 3 Five types of powders were prepared by mixing colored zirconia raw powder (ZPEX yellow: manufactured by Tosoh Corporation) and zirconia raw powder (Zpex Smile: manufactured by Tosoh Corporation) in ratios of 1:0, 3:1, 1:1, 1:3, and 0:1. Each powder was filled into a mold (Φ20mm, t56mm) in 3.6g portions and press molded (surface pressure: 15kN) to obtain a zirconia molded body with a five-layer structure stacked in parallel. Furthermore, the zirconia molded body was subjected to CIP treatment (maximum load pressure: 50MPa, holding time: 1 minute). After that, it was calcined in an electric furnace (1000℃, 30 minutes) to produce a zirconia pre-sintered body. The data of the anterior single crown shape was arranged on the obtained zirconia pre-sintered body for dental cutting processing as shown in Figure 10. Specifically, natural teeth have a three-dimensional gradation of color tone from the cervical to the incisal edge, but in Comparative Example 3, all layers are stacked in parallel from the cervical to the incisal edge, so the fifth layer, which is the darkest in color, was arranged to be the cervical area. Based on the arranged data, a model of a single crown shape for an anterior tooth was made using a cutting machine (DWX-52DCi, manufactured by Roland DG Corporation). The single crown model was sintered at 1450℃ for 2 hours.

[0108] The anterior single crown models of Example 2, Comparative Example 2, and Comparative Example 3 were evaluated for three points: (1) reproducibility of the dentin structure near the cervical area, (2) gradation of the colored area, and (3) reproducibility of natural teeth. The evaluation was performed visually by three evaluators and was evaluated according to the three-level evaluation criteria described below. Table 3 shows the evaluation results by the three evaluators.

[0109] (1) Evaluation criteria for reproducibility of dentin structure near the cervical region 3: The reproduction is adequate. 2: Some parts cannot be reproduced, but it is still fully usable in clinical practice. 1: Not reproducible.

[0110] (2) Evaluation criteria for the gradation of colored parts 3: The interface of the colored portion is barely visible. 2: The interface of the colored area is partially visible, but the material is fully usable for clinical purposes. 1: The interface of the colored parts is visible.

[0111] (3) Evaluation criteria for reproducibility of natural teeth 3: The reproduction is adequate. 2: Some parts cannot be reproduced, but it is still fully usable in clinical practice. 1: Not reproducible.

[0112] [Table 3]

[0113] In Example 2, the cervical area was colored in a three-dimensional curved shape, so the reproducibility of the dentin structure was excellent. In addition, the amount of metal element carried (coloring density) decreased toward the surface of the model, so a good gradation was obtained. In Comparative Example 2, the reproducibility of the dentin structure of the cervical area was excellent, but no gradation was obtained, and the reproducibility of natural teeth was low. In Comparative Example 3, the zirconia powder was layered in parallel, so the reproducibility of the dentin structure was low. [Industrial Applicability]

[0114] 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]

[0115] 1. Zirconia pre-sintered body 2 Top surface 3. Supporting part 3A First Area 3B Second Area 4 Non-supporting part

Claims

1. A porous molded body for dental cutting that supports a metal element, a first region in which the concentration of at least one of the supported metal elements is within a certain range; a second region adjacent to the first region and in which the concentration of the supported metal element decreases with increasing distance from the first region; A porous molded article for dental cutting, characterized in that at least a portion of the interface between a first region and a second region has a three-dimensional curved shape.

2. A porous molded body for dental cutting that supports a metal element, a first region in which the concentration of at least one of the supported metal elements is within a certain range; A porous molding for dental cutting, characterized in having a second region adjacent to the first region and having a portion in which the concentration of the supported metal element decreases three-dimensionally with increasing distance from the first region.

3. A porous molded body for dental cutting that supports a metal element, a first region in which the concentration of at least one of the supported metal elements is within a certain range; a second region adjacent to the first region and in which the concentration of the supported metal element decreases with increasing distance from the first region; The second region has a portion where the concentration of the metal element supported in the first region decreases along three linear directions perpendicular to each other.

4. 4. The porous molded article for dental cutting according to claim 1, wherein the first region has a semi-ellipsoidal or semi-spherical shape.

5. 4. The porous molded article for dental cutting according to claim 1, wherein the outer shape of the first region has a flat portion.

6. 4. The porous molded article for dental cutting according to claim 1, wherein the outer shape of the first region has flat portions and three-dimensional curved portions connecting the flat portions.

7. 4. The porous molded article for dental cutting according to claim 1, wherein the second region has a portion in which the rate of decrease in the concentration of at least one of the supported metal elements is within a certain range.

8. 4. The porous molding for dental cutting according to claim 1, wherein the second region has a portion in which the rate of decrease in the concentration of at least one of the supported metal elements increases with increasing distance from the first region.

9. 4. The porous molded article for dental cutting according to claim 1, wherein the outer shape of the first region has three flat portions.

10. 4. The porous molded article for dental cutting according to claim 1, wherein the outer shape of the first region has three flat portions and a three-dimensional curved portion connecting the three flat portions.

11. 4. The zirconia pre-sintered body for dental cutting according to claim 1, wherein the metal element is at least one selected from the group consisting of rare earth metal elements and transition metal elements.

12. The metal element is selected from the group consisting of yttrium, calcium, cerium, terbium, nickel, iron, erbium, cobalt, niobium, titanium, praseodymium, zirconium, vanadium, niobium, tantalum and chromium, and contains one or more metal elements.

13. 4. The porous molded body for dental cutting according to claim 1, wherein the metal element is supported on the porous molded body for dental cutting by a metal element support material.

14. 4. The porous green body for dental cutting according to claim 1, which is a pre-sintered zirconia body for dental cutting.

15. A sintered body obtained by cutting the porous molded body for dental cutting according to any one of claims 1 to 3 and then sintering it.

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