Dental block material and dental block

Abstract

To provide a dental block material capable of providing a dental block that exhibits both excellent machinability and toughness.SOLUTION: Provided is a dental block material containing poly(ether ether ketone) and an inorganic filler. The content ratio of the inorganic filler in the dental block material is greater than or equal to 10 mass% and less than 30 mass%, and the melt viscosity of the dental block material at a temperature of 380°C and a shear rate of 1216 (sec-1) is 450-690 Pa sec.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a dental block material and a dental block.

Background Art

[0002] 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 CAD / CAM processed. CAD / CAM processing is a process performed using CAD (Computer Aided Design), which is a system for designing a structure using a computer, and CAM (Computer Aided Manufacturing), which is a system for generating data for processing from the shape data obtained by CAD. However, the dental block material using a thermosetting resin has a problem that CAD / CAM processing is difficult. In addition, the CAD / CAM processed product obtained from the dental block using the dental block material has a problem that it is hard but brittle and easy to cut.

[0003] In response to such problems, Patent Document 1 discloses a dental block material made of a thermoplastic resin having a Vickers hardness, and a flexural strength and a flexural modulus within a predetermined range. Patent Document 2 discloses a resin composite material characterized by containing 100 parts by volume of a polyaryl ether ketone resin having a melt viscosity of 210 to 350 Pa·sec at a temperature of 370 degrees and a shear rate of 1220 (1 / s), and 20 to 60 parts by volume of inorganic particles.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in Patent Documents 1 and 2, no consideration has been given from the viewpoint of a dental block that achieves both machinability and toughness. Machinability refers to the property that chips are finely cut and fly off when machining a dental block. By having machinability, the surface of a processed product of a dental block, such as a dental block molded product, can be smoothed. In addition, if the dental block has high toughness, when the processed product of the dental block is attached to a patient's tooth, the processed product is less likely to be damaged and can be used over a long period of time.

[0006] An object of the present disclosure is to provide a dental block material capable of providing a dental block that achieves both machinability and toughness.

Means for Solving the Problems

[0007] The present disclosure relates to the following content. [1] A dental block material containing polyetheretherketone and an inorganic filler, wherein the content ratio of the inorganic filler in the dental block material is 10% by mass or more and less than 30% by mass, and the melt viscosity of the dental block material at a temperature of 380°C and a shear rate of 1216 (sec -1 ) is 450 to 690 Pa·sec. [2] The dental block material according to [1], wherein the inorganic filler is inorganic particles. [3] The dental block material according to [1] or [2], wherein the inorganic filler is one or more selected from the group consisting of titanium oxide, barium sulfate, barium titanate, and yellow iron oxide. [4] The dental block material according to any one of [1] to [3], wherein the content ratio of the polyetheretherketone in the dental block material is 70 to 80% by mass. [5] The temperature of the polyetheretherketone is 380°C and the shear rate is 1216 (sec-1 ) having a melt viscosity of 370 to 530 Pa·sec, the dental block material according to any one of [1] to [4]. [6] A dental block comprising a block portion and a pin portion, wherein the block portion and the pin portion contain the dental block material according to any one of [1] to [5]. [7] When the dental block is notched to obtain a test piece having a notch portion, the line roughness in the notch portion of the test piece with respect to the direction of the notching is 0.030 or less, the dental block according to [6]. [8] In the tensile strength test of the dental block, the fracture point strain is 7.0 or more, the dental block according to [6] or [7].

Advantages of the Invention

[0008] According to the present disclosure, it is possible to provide a dental block material that can provide a dental block that achieves both easy machinability and toughness.

Brief Description of the Drawings

[0009]

Figure 1

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the present disclosure will be described based on specific embodiments. In this specification, when the lower limit value and the upper limit value of a numerical range are separately described, the numerical range can be a combination of any lower limit value and any upper limit value among them. In the present disclosure, the numerical range represented by "A to B" means a numerical range including the lower limit and the upper limit which are the endpoints.

[0011] In this specification, a dental block refers to a block containing resin for use in CAD / CAM processing. By subjecting the dental block to CAD / CAM processing, a dental prosthesis called a dental block molded product (also referred to as a crown) can be manufactured. This dental block molded product can be used, for example, in patients with dental caries. After removing the carious part, the dental block molded product is used to repair the part of the tooth to be restored, thereby treating dental caries, and it can be mainly used for dental treatment purposes. In this specification, the dental block material refers to the material used in the manufacture of dental blocks. The dental block material can also be referred to as a dental block material composition.

[0012] The dental block material of the present disclosure contains polyetheretherketone (PEEK) and an inorganic filler. The content ratio of the inorganic filler in the dental block material (hereinafter, also simply referred to as the content ratio of the inorganic filler) is 10% by mass or more and less than 30% by mass. And the melt viscosity of the dental block material at a temperature of 380 °C and a shear rate of 1216 (sec -1 ) is 450 to 690 Pa·sec. When the content ratio of the inorganic filler and the melt viscosity of the dental block material are within the above ranges, it is possible to provide a dental block material that achieves both good machinability and toughness.

[0013] When the melt viscosity and the content ratio of the inorganic filler of the dental block material are within the above ranges, it becomes a dental block material that can provide a dental block achieving both good machinability and toughness. The reason is not clear, but the inventors of the present invention speculate as follows. When the content ratio of the inorganic filler is less than 10% by mass, the resin block becomes soft and the cuttability of the dental block decreases. When the content ratio of the inorganic filler is 30% by mass or more, the dental block becomes brittle and the toughness becomes insufficient. And when the melt viscosity of the dental block material is less than 450 Pa·sec, the compressive strength of the dental block becomes low and the toughness becomes insufficient. Also, when the melt viscosity of the dental block material exceeds 690 Pa·sec, the fluidity decreases and the manufacturability of the dental block decreases. Therefore, it is considered that a dental block material capable of providing a dental block that achieves both good machinability and toughness can be obtained by having the content ratio of the inorganic filler and the melt viscosity of the dental block material within the above ranges.

[0014] As described above, the melt viscosity of the dental block material at a temperature of 380°C and a shear rate of 1216 (sec -1 ) is 450 to 690 Pa·sec. Further, it is preferably 500 to 670 Pa·sec, and more preferably 550 to 620 Pa·sec. By being within the above range, it is likely to become a dental block material capable of providing a dental block that achieves both good machinability and toughness. Here, when the measurement temperature of the melt viscosity is 380°C, stable measurement of the melt viscosity is easy to perform. The melt viscosity of the dental block material can be adjusted by changing the melt viscosity of the PEEK used or by changing the content ratio of the inorganic filler in the dental block material. The method for measuring the melt viscosity of the dental block material will be described later.

[0015] The melt viscosity of polyetheretherketone at a temperature of 380°C and a shear rate of 1216 (sec -1 ) is preferably 370 to 530 Pa·sec. Further, it is more preferably 375 to 500 Pa·sec, and even more preferably 380 to 480 Pa·sec. By being within the above range, the melt viscosity of the dental block material is likely to be within the above range. Here, when the measurement temperature of the melt viscosity is 380°C, stable measurement of the melt viscosity is easy to perform. The melt viscosity of PEEK can be adjusted by changing the molecular weight of polyetheretherketone. Examples of PEEK having a melt viscosity within the above range include VESTAKEEP (registered trademark) L4000G (manufactured by EVONIK). The method for measuring the melt viscosity of PEEK will be described later.

[0016] The content ratio of polyetheretherketone in the dental block material is not particularly limited, but is preferably 70 to 90% by mass, more preferably 75 to 85% by mass, and even more preferably 75 to 80% by mass.

[0017] As described above, the content ratio of the inorganic filler in the dental block material is 10% by mass or more and less than 30% by mass. Further, it is preferably 15 to 25% by mass, and more preferably 20 to 25% by mass. By being in the above range, it is easy to become a dental block material that can provide a dental block with further improved machinability. When the dental block material contains a plurality of types of inorganic fillers, the content ratio of the inorganic filler is the total content ratio of the plurality of types of inorganic fillers. The content ratio of the inorganic filler in the dental block material can be adjusted by changing the addition amount of the inorganic filler when manufacturing the dental block material. The content ratio of the inorganic filler can be measured by thermogravimetric (TG) measurement.

[0018] The inorganic filler is not particularly limited, but is preferably an inorganic oxide such as silica, alumina, aluminosilicate glass, silica fiber, praseodymium oxide, erbium oxide, manganese oxide, titanium oxide, barium titanate, and yellow iron oxide. Also, sulfates such as calcium sulfate and barium sulfate are also preferred. Among them, one or more selected from the group consisting of titanium oxide, barium titanate, barium sulfate, and yellow iron oxide are more preferred in terms of the color of the dental block being suitable.

[0019] The inorganic filler may contain inorganic substances other than the above. Examples of the inorganic substances other than the above include praseodymium salts such as praseodymium(III) chloride; erbium salts such as erbium chloride, erbium nitrate, erbium fluoride, and erbium oxalate; and manganese pink in which manganese is solid-dissolved in aluminum oxide. Further, the inorganic filler is preferably inorganic particles. When the inorganic filler is inorganic particles, it is likely to be a dental block material that can provide a dental block that achieves both machinability and toughness. The aspect ratio of the inorganic filler is not particularly limited, but is preferably 5 or less. The lower limit is not particularly limited, and examples include 1 or more and 5 or less. When within the above range, it is likely to be a dental block material that can provide a dental block that achieves both machinability and toughness.

[0020] The dental block material may contain known additives. Examples of the additives include antioxidants, ultraviolet absorbers, and the like.

[0021] The manufacturing method of the dental block material is not particularly limited, but the dental block material can be manufactured, for example, by mixing the above-mentioned polyetheretherketone and inorganic filler in a container while heating. That is, the manufacturing method of the dental block material preferably has a step of heat-mixing the polyetheretherketone and the inorganic filler. In addition, the dental block material can be manufactured by adopting known methods.

[0022] The dental block according to one aspect of the present disclosure will be described with reference to the drawings. The dental block 80 includes a block portion 81 and a pin portion 82 (FIG. 1). The dental block is preferably a molded product of the dental block material of the present disclosure. That is, it is preferable that the block portion 81 and the pin portion 82 contain the dental block material of the present disclosure.

[0023] The block portion 81 is a portion that becomes a molded product of the block portion by CAD / CAM processing. The shape of the block portion 81 is not particularly limited, and can be, for example, a shape such as a rectangular parallelepiped, a cube, a cylinder, or a sphere. For example, when the shape of the block portion is a rectangular parallelepiped, the height X in FIG. 1 is preferably 10 mm to 20 mm, the longitudinal length Y is preferably 10 mm to 20 mm, and the lateral length Z is preferably 15 to 65 mm. The usage method of the molded article of the block portion is not particularly limited. For example, in a patient's oral cavity, it can be used by cutting a decayed tooth to prepare a abutment tooth and covering it from above the abutment tooth. In addition, the molded article of the block portion can also be used as a dental filling or a bridge.

[0024] The pin portion 82 is a portion used when attaching the dental block to a CAD / CAM processing machine. By providing the dental block 80 with the pin portion 82, the dental block can be fixed to the CAD / CAM processing machine, and the position can be adjusted when processing the dental block. The shape of the pin portion is not particularly limited, and a known shape such as a cylindrical shape can be adopted.

[0025] From the viewpoint of productivity, the dental block is preferably an integrally molded article of a block portion and a pin portion using the dental block material of the present disclosure.

[0026] In the tensile strength test of the dental block, the breaking point strain is preferably 7.0 or more, more preferably 8.0 or more, and still more preferably 10.0 or more. When within the above range, the toughness of the dental block is likely to be suitable. When it is less than 7.0, the toughness is likely to be low. The upper limit of the breaking point strain is not particularly limited, but for example, it is preferably 7.0~1 It can be 7.0, 8.0~16.0, 10.0~15.0. When the breaking point strain exceeds 17.0, the accuracy during cutting may decrease. The breaking point strain can be adjusted by the content ratio of the inorganic filler. Specifically, as the content ratio of the inorganic filler increases, the breaking point strain is likely to decrease. And as the content ratio of the inorganic filler decreases, the breaking point strain is likely to increase. The method for measuring the breaking point strain of the dental block will be described later.

[0027] When a test piece having a notch portion is obtained by notch processing the dental block, the line roughness (Rz) with respect to the notch processing direction at the notch portion of the test piece is preferably 0.030 or less. For notch machining, NOTCHING TOOL A manufactured by Toyo Seiki is used. Then, the dental block is notch-machined to obtain a test piece corresponding to JIS K 7111-1 / 1eA. At this time, the notch machining of the dental block is performed by applying a cutting edge for notch machining (model number 7505269, which is a standard accessory of NOTCHING TOOL A) to the dental block so as to be perpendicular to the length direction of the dental block and parallel to the thickness direction, moving the cutting edge in the length direction of the dental block, cutting the dental block in a V shape, and forming a notch portion. That is, the notch portion extends in the length direction of the test piece, and the shape of the notch is V-shaped when viewed from the length direction of the test piece. When the test piece is viewed from the thickness direction, the innermost portion extending in the length direction of the test piece (the valley bottom portion when the test piece is viewed from the length direction) can be said to be the tip of the notch portion.

[0028] And, the line roughness with respect to the notch machining direction in the notch portion is measured. The line roughness is a definition of surface roughness and is defined in JIS B 0601-2001. That is, a large line roughness with respect to the notch machining direction in the notch portion indicates that the surface of the notch portion is rough. That is, it indicates that notch machining is difficult to perform and that the machinability is likely to be low. Conversely, it can be said that the smaller the line roughness, the more excellent the machinability tends to be. The specific measurement method will be described later. It is more preferable that the line roughness is 0.025 or less, further preferably 0.020 or less, and particularly preferably 0.014 or less. When it is within the above range, the machinability of the dental block becomes suitable. If it exceeds 0.030, the machinability may decrease. The lower limit of the line roughness is not particularly limited, but for example, preferably 0.000 to 0.030, 0.000 to 0.025, 0.005 to 0.020, 0.005 to 0.014 can be mentioned. The value of the line roughness can be adjusted by the content ratio of the inorganic filler. Specifically, when the content ratio of the inorganic filler increases, the value of the line roughness tends to decrease. And, when the content ratio of the inorganic filler decreases, the value of the line roughness tends to increase. The measurement method of the line roughness will be described later.

[0029] The manufacturing method of the dental block is not particularly limited, but the dental block can be manufactured, for example, by molding the dental block material of the present disclosure using a known molding method such as injection molding or extrusion molding. That is, the manufacturing method of the dental block preferably includes a step of molding the dental block material of the present disclosure.

[0030] Hereinafter, the measurement methods of the physical properties of the dental block material and the dental block will be described.

[0031] <Method for Measuring the Melt Viscosity of Dental Block Material and Polyether Ether Ketone> Based on JIS K7199, it is measured using a capillary rheometer manufactured by Toyo Seiki. For the measurement sample, the measurement temperature is 380 ° C, and the apparent viscosity at an apparent shear rate of 1216 (sec -1 ) is measured and taken as the melt viscosity. As the measurement sample, a dental block material or polyether ether ketone is used.

[0032] <Method for Measuring the Breaking Point Strain of Dental Block> The toughness of the dental block can be evaluated by measuring the tensile strength of the dental block. The tensile strength of the dental block is measured by the following procedure. Based on JIS K7161, it is measured using an autograph AG-X Plus manufactured by Shimadzu Corporation. The test speed is set to 50 mm / min. For the measurement sample, a multipurpose test piece (type A1), which is a dumbbell-shaped tensile test piece described in JIS K7139, is obtained as a sample with a test piece thickness of 4 mm from the dental block material, which is the raw material of the dental block. The measurement result obtained by this measurement sample is taken as the tensile strength of the dental block.

[0033] <Method for Measuring Line Thickness> The measurement of the line thickness is performed by the following procedure. 1. A multipurpose test piece (type A1), which is a dumbbell-shaped tensile test piece described in JIS K 7139, is obtained as a measurement sample from the dental block material, which is the raw material of the dental block. 2. Notch the dumbbell test piece using the NOTCHING TOOL A manufactured by Toyo Seiki to produce a test piece with a notch corresponding to JIS K 7111-1 / 1eA. 3. Obtain the uneven image including the notch using the Keyence one-shot 3D shape measuring machine VR-3000. 4. Determine the line roughness in the notch portion with respect to the notch machining direction from the obtained uneven image. Specifically, when viewing the uneven image from the thickness direction of the test piece, a straight line extending in the length direction of the test piece is provided along the tip of the notch portion. Then, when viewing the uneven image from the thickness direction of the test piece, five straight lines are provided on each side at intervals of 0.06 mm centered on the straight line along the tip of the notch portion, for a total of 11 straight lines. After that, measure the line roughness of the notch portion on each straight line. At this time, a range of 0.5 mm from each end in the notch machining direction of the notch portion is excluded from the measurement target of the line roughness, and the remaining portion is the measurement target. The arithmetic mean value of the obtained line roughness is defined as the line roughness in the notch portion with respect to the notch machining direction.

[0034] Also, the evaluation criteria for machinability are as follows. A: The value of the line roughness is 0.014 or less. B: The value of the line roughness exceeds 0.014 and is 0.030 or less. C: The value of the line roughness exceeds 0.030 and is 0.050 or less. D: The value of the line roughness exceeds 0.050.

[0035] Each configuration and their combinations in each embodiment are examples, and within the scope not departing from the gist of the present invention, additions, omissions, substitutions, and other changes to the configuration can be made as appropriate. The present disclosure is not limited by the embodiments, but is limited only by the scope of the claims.

Examples

[0036] Hereinafter, the present disclosure will be specifically described with reference to examples. However, the present disclosure is not limited to the aspects of the following examples.

[0037] [Example 1] 100 parts by mass of polyetheretherketone (VESTAKEEP® L4000G, manufactured by EVONIK) as a base resin was pulverized so that the average particle size d50 became 10 μm to obtain a PEEK pulverized product. Subsequently, 10 parts by mass of titanium oxide as an inorganic filler was mixed with the PEEK pulverized product by twin-screw kneading to obtain a dental block material. The obtained dental block material was injection-molded by heat melting to obtain a dental block in which the shape of the block portion was a rectangular parallelepiped and the shape of the pin portion was a cylinder. The processing time was as described in Table 1. Each of the above measurements was performed on the dental block. The obtained physical properties are shown in Table 1.

[0038] [Examples 2 to 6] A dental block material and a dental block were obtained in the same manner as in Example 1 except that the type and content ratio of the inorganic filler were as described in Table 1. The physical properties of the obtained dental block are shown in Table 1.

[0039] [Comparative Examples 1 to 3] A dental block material and a dental block were obtained in the same manner as in Example 1 except that the type of the base resin and the type and content ratio of the inorganic filler were as described in Table 1. The physical properties of the obtained dental block are shown in Table 1. In the table, 2000G indicates VESTAKEEP® 2000G, manufactured by EVONIK.

Table 1

Industrial Applicability

[0040] According to the present disclosure, it is possible to provide a dental block material capable of providing a dental block that achieves both machinability and toughness. That is, the dental block material of the present disclosure can be used for manufacturing a dental block.

Claims

1. A dental block material containing polyetheretherketone and an inorganic filler, wherein the content ratio of the inorganic filler in the dental block material is 10% by mass or more and less than 30% by mass, The dental block material has a melt viscosity of 450 to 690 Pa·sec at a temperature of 380°C and a shear rate of 1216 (sec －１ ). Dental block material.

2. The dental block material according to Claim 1, wherein the inorganic filler is inorganic particles.

3. The dental block material according to Claim 1 or 2, wherein the inorganic filler is one or more selected from the group consisting of titanium oxide, barium sulfate, barium titanate, and yellow iron oxide.

4. The dental block material according to Claim 1 or 2, wherein the content ratio of the polyetheretherketone in the dental block material is 70 to 80% by mass.

5. The melt viscosity of the polyetheretherketone at a temperature of 380°C and a shear rate of 1216 (sec －１ is 370 to 530 Pa·sec, and the dental block material according to claim 1 or 2.

6. A dental block comprising a block portion and a pin portion, wherein the block portion and the pin portion contain the dental block material according to Claim 1 or 2.

7. The dental block according to Claim 6, wherein when a test piece having a notch portion is obtained by notching the dental block, the line roughness in the notch portion of the test piece with respect to the direction of the notching is 0.030 or less.

8. The dental block according to Claim 6, wherein in the tensile strength test of the dental block, the breaking point strain is 7.0 or more.

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