Dental block material and dental block using the same

Abstract

To provide a dental block material using a thermoplastic resin that is easy to process with CAD / CAM and has sufficient hardness for use as a CAD / CAM processed product. [Solution] The dental block material according to the present invention is made of a thermoplastic resin having a Vickers hardness of 20HV0.2 to 35HV0.2 as defined in JIS Z 2244, a flexural strength of 150MPa to 250MPa and a flexural modulus of 2 to 10GPa as defined in JIS T 6517:2011.

Description

Technical Field

[0001] The present invention relates to a dental block material and a dental block using the same. More specifically, it relates to a dental block material made of a thermoplastic resin having a Vickers hardness of 20 HV0.2 to 35 HV0.2 as defined in JIS Z 2244, a flexural strength of 150 MPa to 250 MPa as defined in JIS T 6517:2011, and a flexural modulus of 2 to 10 GPa, and a dental block using the same.

Background Art

[0002] In this specification, a dental block refers to a block made of resin for use in CAD / CAM processing. By processing this dental block with CAD / CAM, a dental prosthesis called a CAD / CAM processed product (crown) can be manufactured. This CAD / CAM processed product can be used, for example, in a patient with dental caries by trimming the carious part and then supplementing the CAD / CAM processed product to the part to be restored in the tooth to treat the dental caries, and it can be mainly used for dental treatment purposes.

[0003] In this specification, a dental block material refers to a material used in a dental block. Conventionally, as a dental block material, a dental block material using a thermosetting resin on a metal pedestal has been used, and a dental block using this dental block material has been processed by CAD / CAM.

[0004] Patent Document 1 describes a dental cutting resin cured body composed of a cured product of a composition containing (a) an inorganic filler containing 55 wt% or more of an element of Group 2 and / or Group 13 in the periodic table in terms of oxide, (b) a polymerizable monomer, and (c) a polymerization initiator, and discloses a dental block material using a thermosetting resin.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] However, dental block materials using thermosetting resins are difficult to process using CAD / CAM technology, and CAD / CAM-processed products obtained from dental blocks using these materials have the drawback of being hard but brittle and prone to cracking. Therefore, there has been a desire to prepare dental block materials using thermoplastic resins.

[0007] On the other hand, dental block materials using thermoplastic resins have problems with properties such as hardness not being sufficient for use as CAD / CAM processed materials. Therefore, there has been a demand for the development of dental block materials using thermoplastic resins that are easy to process with CAD / CAM and also possess sufficient hardness, high flexural strength, and low flexural modulus for use as CAD / CAM processed materials.

[0008] In light of the above problems, we conducted intensive research and discovered that a thermoplastic resin with a Vickers hardness of 20HV0.2 to 35HV0.2 as defined in JIS Z 2244, a bending strength of 150MPa to 250MPa, and a bending modulus of 2 to 10GPa as defined in JIS T 6517:2011 can be used to obtain a dental block material that is suitable for CAD / CAM processing and has sufficient hardness for use as a CAD / CAM processed product. This led to the present invention. [Means for solving the problem]

[0009] The invention according to claim 1 relates to a dental block material made of a thermoplastic resin having a Vickers hardness of 20HV0.2 to 35HV0.2 as defined in JIS Z 2244, a flexural strength of 150MPa to 250MPa and a flexural modulus of 2 to 10GPa as defined in JIS T 6517:2011.

[0010] The invention according to claim 2 relates to the dental block material according to claim 1, wherein the thermoplastic resin is one or more thermoplastic resins selected from the group consisting of polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polycarbonate (PC), and modified polyphenylene ether (m-PPE), and the dental block material further comprises 1 wt% to 30 wt% of an inorganic filler.

[0011] The invention according to claim 3 relates to the dental block material according to claim 2, wherein the inorganic filler comprises a praseodium compound, an erbium compound and / or a manganese compound, and titanium oxide.

[0012] The invention according to claim 4 relates to a dental block material according to any one of claims 1 to 3, wherein the dental block material is a dental block material for reuse after being processed with a dental CAD / CAM device.

[0013] The invention according to claim 5 relates to a dental block material for reuse, wherein the dental block material comprises 60 wt% to 80 wt% of the dental block material described in any one of claims 1 to 4 before cutting with a dental CAD / CAM device, and 20 wt% to 40 wt% of the dental block material described in any one of claims 1 to 4 obtained as waste when cutting with a dental CAD / CAM device.

[0014] The invention according to claim 6 relates to a dental block comprising (a) a block portion and (b) a pin portion, wherein the block portion and the pin portion are made of the dental block material described in any one of claims 1 to 5.

[0015] The invention according to claim 7 relates to the dental block according to claim 6, wherein the block portion and the pin portion are integrally molded.

[0016] The invention according to claim 8 relates to a dental block according to claim 6 or 7, wherein the shape of the block portion is selected from the group consisting of a rectangular parallelepiped, a cube, a cylinder, and a sphere.

[0017] The invention according to claim 9 relates to a dental block according to any one of claims 6-8, wherein the block portion is 110 wt% to 500 wt% of the weight of a CAD / CAM workpiece obtained by cutting with a dental CAD / CAM device.

[0018] The invention according to claim 10 relates to the dental block according to claim 9, wherein the block portion is 150 wt% to 300 wt% of the weight of the CAD / CAM workpiece obtained by cutting with a dental CAD / CAM device. [Effects of the Invention]

[0019] According to the invention of claim 1, the dental block material is made of a thermoplastic resin having a Vickers hardness of 20HV0.2 to 35HV0.2 as defined in JIS Z 2244, a bending strength of 150MPa to 250MPa as defined in JIS T 6517:2011, and a bending modulus of 2 to 10GPa. Therefore, it has an appropriate amount of bending strength, making it suitable for CAD / CAM processing, and it can be made into a dental block material that has sufficient hardness, high bending strength, and low bending modulus when used as a CAD / CAM processed product. Furthermore, compared to dental block materials that do not have the above characteristics, the processing time by CAD / CAM equipment can be shortened. In addition, since the dental block obtained from this dental block material is made of thermoplastic resin, the dental block can be reused by thermally melting and injection molding the surplus dental block obtained as waste when cutting with a CAD / CAM equipment.

[0020] According to the invention of claim 2, the thermoplastic resin is one or more thermoplastic resins selected from the group consisting of polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polycarbonate (PC), and modified polyphenylene ether (m-PPE), and the dental block material further contains 1 wt% to 30 wt% of inorganic filler, so that a dental block material can be provided that has an appropriate amount of flexural strength that is easy to process with CAD / CAM, and also has sufficient hardness for use as a CAD / CAM processed product. Furthermore, since the inorganic filler also acts as a pigment, the dental block material can be given color.

[0021] According to the invention of claim 3, the inorganic filler comprises a praseodium compound, an erbium compound and / or a manganese compound, and titanium oxide, so that a white CAD / CAM product having the same color as other teeth in the patient's oral cavity can be provided from this dental block material.

[0022] According to the invention of claim 4, since the dental block material is a dental block material that is to be reused after being processed with a dental CAD / CAM device, it is possible to provide a dental block material that can make use of even the surplus dental blocks obtained as waste during CAD / CAM processing without waste.

[0023] According to the invention of claim 5, a dental block material for reuse is provided, wherein the dental block material comprises 60 wt% to 80 wt% of the dental block material described in any one of claims 1 to 4 before cutting with a dental CAD / CAM device, and 20 wt% to 40 wt% of the dental block material described in any one of claims 1 to 4 obtained as waste when cutting with a dental CAD / CAM device. Therefore, the dental block material can be reused without degrading the properties of the dental block, and a dental block material can be provided that has an appropriate amount of bending strength for easy CAD / CAM processing, as well as sufficient hardness, bending strength, and bending modulus for use as a CAD / CAM processed product.

[0024] According to the invention according to claim 6, there is provided a dental block comprising (a) a block portion and (b) a pin portion, wherein the block portion and the pin portion are made of the dental block material according to any one of claims 1 - 5. Therefore, since it has an appropriate amount of bending strength, it is suitable for CAD / CAM processing and has sufficient hardness for use as a CAD / CAM processed product, thus providing a dental block. Further, since the thermoplastic resin can be injection molded, a dental block having a shape close to the desired shape and size of the CAD / CAM processed product in advance can be manufactured. Therefore, the time required for CAD / CAM processing can be shortened, and it becomes possible to quickly provide the desired CAD / CAM processed product.

[0025] According to the invention according to claim 7, since the block portion and the pin portion are integrally formed, a dental block can be provided without using an adhesive, and this dental block can be CAD / CAM processed without using a pin portion made of metal. Further, even when reusing the dental block obtained as waste during CAD / CAM processing, the dental block can be directly thermally melted. Therefore, compared with the conventional dental block having a pin portion made of metal, the dental block can be reused at low cost and simply.

[0026] According to the invention according to claim 8, since the shape of the block portion is a shape selected from the group consisting of a rectangular parallelepiped, a cube, a cylinder, and a sphere, the time for CAD / CAM processing can be shortened by making the block portion conform to the size and shape of the CAD / CAM processed product to be manufactured in advance, and the amount of surplus dental block as waste can also be reduced.

[0027] According to the invention according to claim 9, since the block portion is 110 wt% - 500 wt% of the weight of the CAD / CAM processed product obtained by cutting with a dental CAD / CAM device, the time for CAD / CAM processing can be shortened, and the desired CAD / CAM processed product can be quickly provided. Further, since the amount of surplus dental block as waste can also be reduced, a dental block with less environmental load can be provided.

[0028] According to the invention of claim 10, since the block portion is 150 wt% to 300 wt% of the weight of the CAD / CAM workpiece obtained by cutting with a dental CAD / CAM device, the CAD / CAM processing time can be shortened, and the desired CAD / CAM workpiece can be provided quickly. In addition, the amount of excess dental block waste can be reduced, so a dental block with a lower environmental impact can be provided. [Brief explanation of the drawing]

[0029] [Figure 1] This is a perspective view of a dental block according to one embodiment of the present invention. [Figure 2] (a) A perspective view of a dental block according to one embodiment of the present invention. (b) A plan view of a dental block according to one embodiment of the present invention. [Figure 3] (a) A perspective view of a dental block according to one embodiment of the present invention. (b) A plan view of a dental block according to one embodiment of the present invention. [Figure 4] This is a side view of a dental block according to one embodiment of the present invention. [Figure 5] This is an explanatory diagram showing how a CAD / CAM product obtained from a dental block according to an embodiment of the present invention is fitted onto a patient's teeth in the oral cavity. [Modes for carrying out the invention]

[0030] A preferred embodiment of the dental block material according to the present invention (hereinafter also simply referred to as "this dental block material") will be described below.

[0031] This dental block material is made of a thermoplastic resin that possesses a certain level of hardness, bending strength, and flexural modulus, in order to be easy to process using CAD / CAM technology and to have sufficient hardness, flexural strength, and flexural modulus for use as a CAD / CAM processed object.

[0032] More specifically, this dental block material is made of a thermoplastic resin with a Vickers hardness of 20HV0.2 to 35HV0.2 and a flexural strength of 150MPa to 250MPa. Therefore, this dental block material has sufficient hardness and appropriate toughness for use as a CAD / CAM processed product (90), making it less prone to cracking and easier to process during CAD / CAM processing. If the Vickers hardness of the thermoplastic resin is less than 20HV0.2, it is not hard enough for use as a CAD / CAM processed product (90), resulting in low durability when used in a patient's oral cavity. On the other hand, if the Vickers hardness of the thermoplastic resin exceeds 35HV0.2, although it has sufficient hardness, CAD / CAM processing is time-consuming, making it difficult to provide CAD / CAM processed products (90) quickly. Furthermore, if the flexural strength of the thermoplastic resin is less than 150MPa, it lacks toughness and is prone to cracking when used as a CAD / CAM processed product (90) over a long period of time. On the other hand, if the flexural strength of the thermoplastic resin exceeds 250 MPa, although it has sufficient toughness, the flexural modulus improves, making it prone to cracking in the oral cavity. Furthermore, it becomes difficult to quickly provide CAD / CAM processed parts (90). Additionally, if the flexural modulus of the thermoplastic resin is 2 GPa or less, the material is too tough and there is a risk of deformation, and if it is 10 GPa or more, the material becomes brittle, increasing the risk of fracture in the oral cavity.

[0033] Any thermoplastic resin with a Vickers hardness of 20HV0.2 to 35HV0.2, a flexural strength of 150MPa to 250MPa, and a flexural modulus of 2 to 10GPa can be used, with engineering plastics being particularly preferable. For example, suitable thermoplastic resins include polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polycarbonate (PC), modified polyphenylene ether (m-PPE), polyaryl ketone (PAK), polyether ether ether ketone (PEEEK), polyether ether ketone ketone (PEEKK), polyether ketone ether ketone ether ketone (PEKEKEK), polyether ketone ketone ketone (PEKKK), or combinations thereof. Furthermore, it is particularly preferable to use PEEK, PEKK, PC, m-PPE, or combinations thereof as thermoplastic resins.

[0034] This dental block material preferably contains the above-mentioned thermoplastic resin as its main component, and the content is preferably 60 wt% to 100 wt%. If the thermoplastic resin content is less than 60 wt%, a dental block material with a Vickers hardness of 20 HV 0.2 to 35 HV 0.2, a flexural strength of 150 MPa to 250 MPa, and a flexural modulus of 2 to 10 GPa cannot be obtained, making CAD / CAM processing difficult and resulting in insufficient properties for use as a CAD / CAM processed material.

[0035] This dental block material preferably contains an appropriate amount of inorganic filler. The inorganic filler can be any inorganic oxide with a melting point of 500°C or higher, such as silica, alumina, aluminosilicate glass, silica fiber, praseodymium compounds, erbium compounds and / or manganese compounds, titanium oxide, yellow iron oxide, or combinations thereof. By including inorganic filler in this dental block material, physical properties such as hardness and flexural strength can be suitably adjusted. Furthermore, it is more preferable to use a combination of inorganic filler containing praseodymium compounds, erbium compounds and / or manganese compounds, and titanium oxide with a thermoplastic resin consisting of PEEK, PEKK, PC, m-PPE, or combinations thereof, as this easily imparts characteristics such as a Vickers hardness of 20HV0.2 to 35HV0.2, a flexural strength of 150MPa to 250MPa, and a flexural modulus of 2 to 10GPa.

[0036] In this specification, praseodium compounds refer to compounds that primarily contain praseodium oxide, and also contain salts such as praseodymium(III) chloride.

[0037] In this specification, erbium compounds refer to compounds that primarily contain erbium oxide, and in addition contain salts of erbium chloride, erbium nitrate, erbium fluoride, or erbium oxalate.

[0038] In this specification, manganese compounds refer to compounds that mainly contain manganese and are dissolved in aluminum oxide, such as manganese pink and manganese oxide. Since inorganic fillers also act as pigments, their colors can be imparted to dental block materials. For example, praseodium oxide can impart yellow, erbium oxide and / or manganese compounds can impart red, and titanium oxide can impart white to this dental block material. The inorganic filler content can be, for example, 1wt%~30wt%, 1wt%~40wt%, 1wt%~50wt%, 5wt%~30wt%, 10wt%~30wt%, 15wt%~30wt%, 20wt%~30wt%, 25wt%~30wt%, 5wt%~35wt%, 15wt%~35wt%, 20wt%~35wt%, 25wt%~35wt%, 25wt%~40wt%, 20wt%~50wt%, or 30wt%~60wt%. Furthermore, an inorganic filler content of 1wt%~30wt% is preferable, as it provides a suitable color to the dental block material while also imparting a certain level of hardness, flexural strength, and flexural modulus. If the inorganic filler content is less than 1 wt%, the color of the inorganic filler cannot be sufficiently imparted to the dental block material. If the inorganic filler content exceeds 30 wt%, the flexural modulus of the dental block material increases, making it more brittle.

[0039] It is preferable to use an inorganic filler that combines three types: praseodium oxide, erbium oxide and / or manganese pink, and titanium oxide. This provides the tooth's natural white color while also providing a certain degree of hardness and flexural strength.

[0040] For example, when incorporating 10 wt% of an inorganic filler containing praseodium oxide, erbium oxide and / or manganese compounds, and titanium dioxide into this dental block material, the praseodium oxide content can be 1 wt% to 2 wt%, the erbium oxide and / or manganese compound content can be 0.01 wt% to 1 wt%, and the titanium dioxide content can be 7 wt% to 9 wt%.

[0041] As another example, when incorporating 20 wt% of an inorganic filler containing praseodium oxide, erbium oxide and / or manganese compounds, and titanium dioxide into this dental block material, the praseodium oxide content can be 1 wt% to 2 wt%, the erbium oxide and / or manganese compound content 0.01 wt% to 1 wt%, and the titanium dioxide content 17 wt% to 19 wt%.

[0042] As another example, when incorporating 30 wt% of an inorganic filler containing praseodium oxide, erbium oxide and / or manganese compounds, and titanium dioxide into this dental block material, the praseodium oxide content can be 1 wt% to 2 wt%, the erbium oxide and / or manganese compound content 0.01 wt% to 1 wt%, and the titanium dioxide content 27 wt% to 29 wt%.

[0043] This dental block material is suitable for reuse after processing with a dental CAD / CAM system. This is because, since this dental block material uses thermoplastic resin as its main component, it can be re-injected after being injection-molded as a dental block (80) by thermal melting. In this way, because this dental block material can be reused, it can reduce material costs and environmental impact compared to conventional dental block materials that use thermosetting resins.

[0044] This dental block material is not limited to inorganic fillers and may contain other additives. Any such additive that is obvious to those skilled in the art may be used.

[0045] The manufacturing method for this dental block material involves mixing the thermoplastic resin and inorganic filler described above in a container while heating them. The manufacturing method for the dental block material is not particularly limited, and any method obvious to those skilled in the art can be used.

[0046] For reuse, the dental block material can preferably be made containing 60 wt% to 80 wt% of the dental block material before cutting with a dental CAD / CAM device and 20 wt% to 40 wt% of the dental block material obtained as waste during cutting with a dental CAD / CAM device. The inventors have found that by blending in the above proportions, it is possible to provide a dental block (80) that maintains almost the same properties as the unprocessed dental block material. As a result, by using the above proportions of the dental block material, it is possible to provide a dental block material that has an appropriate amount of bending strength for easy CAD / CAM processing and sufficient hardness for use as a CAD / CAM processed product (90).

[0047] Preferred embodiments of the dental block according to the present invention (hereinafter also simply referred to as "the dental block") will be described with reference to the attached drawings.

[0048] Figure 1 is a perspective view of a dental block according to one embodiment of the present invention. Figure 2a is a perspective view of a dental block according to one embodiment of the present invention. Figure 2b is a plan view of a dental block according to one embodiment of the present invention. Figure 3a is a perspective view of a dental block according to one embodiment of the present invention. Figure 3b is a plan view of a dental block according to one embodiment of the present invention. Figure 4 is a side view of a dental block according to one embodiment of the present invention.

[0049] As shown in Figure 1, the dental block (80) comprises a block portion (81) and a pin portion (82). The dental block (80) is formed from the dental block material described above and is the material used for actual processing when set in a CAD / CAM device.

[0050] The block portion (81) is the part that becomes a CAD / CAM processed product (90) through CAD / CAM processing. The shape of the block portion (81) can be, for example, a rectangular prism, a cube, a cylinder, or a sphere. For example, if the shape of the block portion (81) is a rectangular prism, the height X shown in Figure 1 is preferably 10 mm to 20 mm, the vertical length Y is preferably 10 mm to 20 mm, and the horizontal length Z is preferably 15 mm to 65 mm. If the height X, vertical length Y, and horizontal length Z are less than the minimum values, it is difficult to create the shape of a tooth crown, and if they exceed the maximum values, the processing time is longer and the amount of dental block (80) waste increases.

[0051] Figure 2 shows a block section (81) with a cylindrical shape. Alternatively, as shown in Figure 3, the block section (81) can have a fan-shaped form.

[0052] The shape of the block portion (81) is not limited to the shape described above; for example, as shown in Figure 4, a block portion (81) with a shape that conforms to the tooth crown can also be used. In the example in Figure 4, a block portion (81) with a roughly M-shaped side is used. By making the shape and size of the block portion (81) similar to the shape and size of the target workpiece, the CAD / CAM machining time can be shortened, and the amount of excess dental block (80) that is waste can also be reduced.

[0053] The pin portion (82) is a jig for attachment to a CAD / CAM machining center. Therefore, by providing the pin portion (82), the dental block (80) can be fixed to the CAD / CAM machining center and adjusted to a specific position during machining. The shape of the pin portion (82) is not particularly limited, and any shape of the pin portion (82) that is obvious to those skilled in the art can be used. For example, a cylindrical pin portion (82) can be used, and this pin portion (82) may have a groove for attachment to a CAD / CAM machining center as appropriate.

[0054] Both the block portion (81) and the pin portion (82) are made of the aforementioned dental block material. Therefore, the block portion (81) and the pin portion (82) have a Vickers hardness of 20HV0.2 to 35HV0.2, a bending strength of 150MPa to 250MPa, and a bending modulus of elasticity of 2 to 10GPa, respectively. Thus, the dental block (80) is easy to process using CAD / CAM and can provide a CAD / CAM processed product (90) with sufficient hardness.

[0055] In this dental block (80), it is preferable to integrally mold the block portion (81) and the pin portion (82) using this dental block material. By doing so, the dental block (80) can be manufactured simply and in large quantities, and the manufacturing cost of the dental block (80) can be reduced. Furthermore, since the dental block (80) in which the block portion (81) and the pin portion (82) are integrally molded can be reused by simply melting down the dental block (80) obtained as waste after CAD / CAM processing, costs can be reduced and the burden on the environment can be minimized.

[0056] The weight of the block portion (81) can be, for example, 110 wt% to 500 wt% or 150 wt% to 300 wt% of the weight of the CAD / CAM workpiece (90) obtained by cutting with a dental CAD / CAM device. If the weight range is less than each minimum value, the weight of the block portion (81) is too small, making CAD / CAM machining difficult. If the weight range exceeds each maximum value, CAD / CAM machining takes a long time, and the amount of excess dental block (80) that becomes waste increases.

[0057] The dental block (80) can be manufactured, for example, by liquefying the dental block material with heat, pouring it into an injection mold of any shape, and cooling and solidifying it. Thus, the manufacturing method for the dental block (80) can be, for example, injection molding, but any method obvious to those skilled in the art can be used.

[0058] The CAD / CAM processed product (90) can be obtained, for example, by processing the dental block (80) with a CAD / CAM device. As shown in Figure 5, the CAD / CAM processed product (90) can be used, for example, when one of the teeth (91) on the gums (93) in a patient's oral cavity becomes decayed, by grinding down the tooth (91) to create an abutment tooth (92), and then placing the CAD / CAM processed product (90) over the abutment tooth (92). However, the use of the CAD / CAM processed product (90) is not limited to the examples described above. The CAD / CAM processed product (90) can also be used as a filling or a bridge, in which case the shape of the CAD / CAM processed product (90) is processed to resemble a filling or a bridge before use. [Examples]

[0059] The effects of the present invention will be made clearer by illustrating examples of dental block materials and dental blocks according to the present invention below. However, the present invention is not limited in any way to the following examples.

[0060] [Examples 1-8] (Manufacturing of dental blocks and CAD / CAM processed products using them) In Examples 1-8, thermoplastic resins mixed in the proportions shown in Tables 1 and 2 were pulverized to an average particle size d50 = 10 μm. Subsequently, titanium dioxide, praseodium oxide, and erbium oxide or manganese pink were mixed into the pulverized material as inorganic fillers, and the resulting dental block material was injection molded by thermal melting to produce dental blocks with a rectangular block shape. The composition of the dental blocks, the size of the block portion, and the processing time for Examples 1-8 are shown in Tables 1 and 2.

[0061] The dental blocks obtained in Examples 1-8 were processed into molar-sized models using a dental milling machine DWX-52D (manufactured by Matsukaze Co., Ltd.) to obtain CAD / CAM-processed parts.

[0062] (Measurement test) The Vickers hardness of the CAD / CAM workpieces obtained in Examples 1-8 was measured according to the test method specified in JIS Z 2244. Bending strength, water absorption, and dissolution were also measured according to the test method specified in JIS T 6517:2011. Furthermore, the color of the CAD / CAM workpieces obtained in Examples 1-8 was measured using a colorimeter. For the measurement, a CAD / CAM block was processed to a thickness of 2.0 mm, color measurement was performed, and the color difference with VITA Shade Guide A3 was measured. The results are shown in Tables 1 and 2.

[0063] [Comparative Example 1] By varying the mixing ratio of thermoplastic resin and inorganic filler, a dental block of Comparative Example 1 and a CAD / CAM processed product using it were manufactured using the same manufacturing method as for the dental blocks of Examples 1-8.

[0064] [Comparative Example 2] A thermosetting resin was molded by heating and pressure polymerization to obtain a dental block of Comparative Example 2 (Matsukaze Block HC, Matsukaze Co., Ltd.). The obtained dental block of Comparative Example 2 was processed into a molar-sized model using a dental milling machine DWX-52D (manufactured by Matsukaze Co., Ltd.) to obtain a CAD / CAM processed product.

[0065] (Measurement test) The Vickers hardness of the CAD / CAM workpieces obtained in Comparative Example 1 and Comparative Example 2 was measured according to the test method specified in JIS Z 2244. In addition, the bending strength, bending modulus, water absorption, and dissolution rate were measured according to the test method specified in JIS T 6517:2011. Furthermore, the color of the CAD / CAM workpieces obtained in Comparative Examples 1 and 2 was measured using a colorimeter. The results are shown in Table 3.

[0066] (Manufacturing of CAD / CAM processed products using recycled dental blocks from Examples 1-8 and Comparative Example 1) Dental blocks from Examples 1-8 and Comparative Example 1 were thermally melted, and the resulting dental block material was injection molded again to produce dental blocks with a rectangular prism shape. The obtained dental blocks were processed into molar-sized models using a dental milling machine DWX-52D (manufactured by Matsukaze Co., Ltd.) to obtain CAD / CAM processed parts. Note that the dental block from Comparative Example 2 could not be reused because it was made of thermosetting resin.

[0067] (Measurement test) The flexural strength of the recycled CAD / CAM processed parts obtained in Examples 1-8 and Comparative Example 1 was measured according to the test method specified in JIS T 6517:2011. The results are shown in Tables 1, 2, and 3.

[0068] [Table 1]

[0069] [Table 2]

[0070] [Table 3]

[0071] (Consideration) In Examples 1-4, dental blocks were manufactured using PEEK as the thermoplastic resin. From the data in Table 1, it was found that increasing the content of inorganic fillers, including titanium dioxide, praseodymium oxide, and erbium oxide and / or manganese pink, lowered the flexural strength, increased the flexural modulus, and increased the Vickers hardness. Therefore, although the toughness was slightly reduced, it was found that the blocks had sufficient hardness for use as CAD / CAM processed objects in the patient's oral cavity. Furthermore, it was found that dental blocks with a high titanium dioxide content were white in color, which is desirable for use as prosthetics. In addition, even with such dental blocks, the Vickers hardness was in the range of 20HV0.2 to 35HV0.2, the flexural strength was in the range of 150MPa to 250MPa, and the flexural modulus was in the range of 2.0 to 10.0GPa, indicating that the dental blocks possessed a good balance of toughness and sufficient hardness. Furthermore, the bending strength of the recycled dental blocks was within the range of 150 MPa to 250 MPa, suggesting that their physical properties hardly deteriorate even after reuse.

[0072] In Example 5, a dental block was manufactured using PEKK as the thermoplastic resin. In the case of PEKK in Example 5, the Vickers hardness was 24HV0.2, the flexural strength was 189 MPa, and the flexural modulus was 3.0 GPa, indicating that the dental block possessed a good balance of toughness and sufficient hardness. Furthermore, the flexural strength of the recycled dental block was 181 MPa, suggesting that the physical properties hardly deteriorated even after reuse.

[0073] In Example 6, a dental block was manufactured using PC as the thermoplastic resin. In the case of PC in Example 6, the Vickers hardness was 22HV0.2, the flexural strength was 152 MPa, and the flexural modulus was 3.5 GPa, indicating that the dental block possessed a good balance of toughness and sufficient hardness. Furthermore, the flexural strength of the recycled dental block was 149 MPa, suggesting that the physical properties hardly deteriorated even after reuse.

[0074] Comparative Example 1 involved manufacturing a dental block by mixing 35 wt% PEEK with 65 wt% inorganic filler. This dental block had a Vickers hardness of 24 HV 0.2 and a flexural strength of 189 MPa. While it possessed a good balance of toughness and sufficient hardness, its high flexural modulus meant it was likely to break if used long-term in a patient's oral cavity.

[0075] Comparative Example 2 is a dental block molded using a thermosetting resin. The dental block of Comparative Example 2 has sufficient hardness, with a Vickers hardness of 65HV0.2. On the other hand, its flexural strength is 167 MPa and its flexural modulus is 12.0 GPa, indicating a slight lack of toughness, which made it unsuitable for long-term clinical use as a CAD / CAM processed product. Furthermore, because the dental block material of Comparative Example 2 is made of a thermosetting resin, it cannot be reused.

[0076] From the color measurement results of Examples 1-8 and Comparative Examples 1 and 2, it was found that by adding inorganic fillers containing titanium dioxide, praseodium oxide, and erbium oxide and / or manganese pink, the color became considerably closer to that of normal teeth. Therefore, it was found that the CAD / CAM processed products of Examples 1-8 could be used comfortably in the patient's oral cavity. [Industrial applicability]

[0077] The dental block material according to the present invention is made of a thermoplastic resin with a Vickers hardness of 20HV0.2 to 35HV0.2 as defined in JIS Z 2244, a bending strength of 150MPa to 250MPa, and a bending modulus of 2.0 to 10.0GPa as defined in JIS T 6517:2011. Therefore, it has an appropriate amount of bending strength, making it suitable for CAD / CAM processing, and it can be made into a dental block material that has sufficient hardness, high bending strength, and low bending modulus when used as a CAD / CAM processed product. Furthermore, compared to dental block materials that do not have the above characteristics, the processing time by CAD / CAM equipment can be shortened. In addition, since the dental blocks obtained from this dental block material are made of thermoplastic resin, the dental blocks can be reused by thermally melting and injection molding the surplus dental blocks obtained as waste when cutting with a CAD / CAM equipment.

[0078] Therefore, the dental block material according to the present invention can be suitably and widely used as a dental block material that is suitable for CAD / CAM processing and has sufficient hardness for use as a CAD / CAM processed product. [Explanation of Symbols]

[0079] 80 Dental Blocks 81 Block Section 82 Pin section 90 CAD / CAM workpiece 91 teeth 92 Abutment teeth 93 Gums

Claims

1. A dental block material made of thermoplastic resin having a Vickers hardness of 20HV0.2 to 35HV0.2 as defined in JIS Z 2244, a flexural strength of 150 MPa to 250 MPa and a flexural modulus of 2 to 10 GPa as defined in JIS T 6517:2011.

2. The dental block material according to claim 1, wherein the thermoplastic resin is one or more thermoplastic resins selected from the group consisting of polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polycarbonate (PC), and modified polyphenylene ether (m-PPE), and the dental block material further comprises 1 wt% to 30 wt% of an inorganic filler.

3. The dental block material according to claim 2, wherein the inorganic filler comprises a praseodium compound, an erbium compound and / or a manganese compound, and titanium oxide.

4. The dental block material according to any one of claims 1 to 3, wherein the dental block material is a dental block material intended for reuse after being processed with a dental CAD / CAM device.

5. A dental block material used for reuse, wherein the dental block material is The dental block material described in any one of claims 1-4, 60 wt% to 80 wt%, before being cut with a dental CAD / CAM device, A dental block material comprising 20 wt% to 40 wt% of the dental block material described in any one of claims 1 to 4, which is obtained as waste when cutting with a dental CAD / CAM device.

6. (a) Block section and (b) A dental block comprising a pin portion, A dental block wherein the block portion and the pin portion are made of the dental block material described in any one of claims 1 to 5.

7. The dental block according to claim 6, wherein the block portion and the pin portion are integrally molded.

8. The dental block according to claim 6 or 7, wherein the shape of the block portion is selected from the group consisting of a rectangular parallelepiped, a cube, a cylinder, and a sphere.

9. The dental block according to any one of claims 6-8, wherein the block portion is 110 wt% to 500 wt% of the weight of the CAD / CAM workpiece obtained by cutting with a dental CAD / CAM device.

10. The dental block according to claim 9, wherein the block portion is 150 wt% to 300 wt% of the weight of the CAD / CAM workpiece obtained by cutting with a dental CAD / CAM device.

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