JP2022052540A - Container for manufacturing dental mill blank and manufacturing method of dental mill blank - Google Patents

Abstract

To provide a container for manufacturing a dental mill blank which can improve the filling property of a curable composition to the container in a case of filling the curable composition with low fluidity and can improve a yield when manufacturing the dental mill blank, provide a manufacturing method of the dental mill blank using the container, and provide the dental mill blank which has small cracks and air bubbles and is excellent in the mechanical strength in a case of using the curable composition with low fluidity.SOLUTION: There is provided a container 1 for manufacturing a dental mill blank for filling a paste-like curable composition. The container includes an opening 2 on the upper side of the container. The container comprises a composition filling part having a wall surface which has one or more through holes and the opening.SELECTED DRAWING: Figure 1

Description

The present invention relates to a container for manufacturing a dental mill blank and a method for manufacturing a dental mill blank using the container.

Dental curable compositions composed of polymerizable monomers, inorganic fillers and polymerization initiators are dental materials often used as materials for repairing tooth defects and tooth decay. In recent years, a CAD / CAM system that designs dental prostheses such as inlays and crowns by computer and cuts them with a milling device has become widespread, and is cured as a material to be cut used in this system. A dental mill blank made from a sex composition is being studied. As the dental mill blank, a block body having an appropriate size and having a shape such as a rectangular body, a cylinder, or a disk is supplied, and the material includes glass ceramics, zirconia, titanium, acrylic resin, polymer resin and an inorganic filler. Various materials such as composite materials have been proposed. Since the dental mill blank is worn in the oral cavity for a long period of time, it is required to have no defects such as cracks and bubbles, and to have sufficient mechanical strength to replace natural teeth.

As a method for manufacturing a dental mill blank for the purpose of satisfying such required characteristics, for example, in Patent Document 1, a curable composition before curing is placed in a concave container that is not made of metal, and the entire concave container is used as a whole. A method for manufacturing a dental mill blank is to put it in a container that can have a predetermined pressure, heat it while pressurizing it at a pressure of 1.0 MPa or more, and polymerize it so that the pressure inside and outside the mold becomes equal. It has been disclosed. By this manufacturing method, it is possible to suppress air bubbles and cracks, and it is possible to provide a high-quality dental mill blank such that chipping that lacks details during cutting in CAM does not occur.

However, the consistency of the curable composition described in Patent Document 1 was 30 to 68 mm, which was relatively high fluidity. On the other hand, when the content of the inorganic filler in the curable composition is increased for the purpose of improving the mechanical strength, it is extremely avoided that the consistency of the paste of the curable composition becomes low, that is, the fluidity becomes low. Hateful. As a result of studies by the present inventors, when such a paste having a relatively low fluidity is filled in the concave container, the air in the container does not escape and it is difficult to fill the container without a shortage. I understood. Therefore, it is difficult to mold the obtained dental mill blank into a desired shape, and it is necessary to process it into a rectangular parallelepiped, a cylinder, a disk, or the like in a subsequent process in order to supply it for cutting in CAM. There were problems such as cost increase and increase in waste amount. Furthermore, when polymerization is carried out with air remaining in the container, oxygen in the residual air inhibits the polymerization reaction, resulting in many cracks in the dental mill blank and a decrease in mechanical strength. It turned out that there was.

Further, as another method, in Patent Document 2, after putting the curable composition before curing in a concave container, the concave container is subjected to rotation at least about an inclined axis toward diagonally upward to cure. A method of stirring the sex composition is disclosed. By this manufacturing method, even if air bubbles are entrained or color unevenness occurs when the concave container is filled with the curable composition, the air bubbles entrained by stirring are defoamed and the color unevenness is eliminated. Therefore, a high-strength dental mill blank can be obtained without air bubbles or color unevenness.

However, as a result of studies by the present inventors, when a curable composition having a consistency of less than 30 mm and a low fluidity is used, there is a problem that bubbles cannot be eliminated only by the above-mentioned stirring force. Further, in the method of giving a predetermined rotation to the concave container as shown in Patent Document 2, an excessive load is applied to the curable composition due to the centrifugal force caused by the rotation motion, and the inorganic filler and the polymerizable monomer are applied. There was also the problem of separation.

International Publication No. 2015/045698 Japanese Unexamined Patent Publication No. 2018-2610

The present invention has been made to solve the above-mentioned problems of the prior art, and to improve the filling property of the curable composition into a container when the curable composition having low fluidity is filled. It is an object of the present invention to provide a container for manufacturing a dental mill blank, which can improve the yield when manufacturing a dental mill blank, and a method for manufacturing a dental mill blank using the container. Another object of the present invention is to provide a dental mill blank having few cracks and bubbles and excellent mechanical strength when a curable composition having low fluidity is used.

As a result of intensive research to solve the above problems, the present inventors have separated the inorganic filler and the polymerizable monomer by using a container having a through hole to allow air to pass through. It was found that the curable composition can be filled without a shortage with respect to the container volume, there are few cracks and bubbles in the dental mill blank after polymerization curing, and the mechanical strength is excellent. Based on this, further research was carried out, and the present invention was completed.

The present invention includes the following inventions.
[1] A container for manufacturing a dental mill blank for filling a paste-like curable composition.
It has an opening above the container and has an opening.
A container for manufacturing a dental mill blank, wherein the container includes a wall surface having one or more through holes and a composition filling portion including the opening.
[2] The container for manufacturing a dental mill blank according to [1], wherein the cross-sectional shape of the through hole is circular.
[3] When the diameter of the through hole is ( _ra ) mm and the area of the wall surface having the through hole is (S) mm ² , the following formulas (I) and (II) are satisfied, [1] or The container for manufacturing the dental mill blank according to [2].
0.1 ≤ _ra ≤ 5 (I)
S / 10000 ≤ π * (r _a / 2) ² ≤ S / 6 (II)
[4] The container for manufacturing a dental mill blank according to any one of [1] to [3], wherein the shape of the composition filling portion in the container is a polygonal prism.
[5] The wall surface is a bottom surface, and the distance Z1 between the apex X1 located closest to a specific through hole and the center of gravity Y1 of the through hole among the vertices of the bottom surface forms the apex X1. The container for manufacturing a dental mill blank according to [4], which has the through hole at a position within 30% of the average value of the lengths of the two sides of the bottom surface of the filling portion.
[6] The dental use according to [4] or [5], wherein the wall surface having the through holes is a bottom surface, and the total number of through holes on the bottom surface is 50% or more of the total number of vertices on the bottom surface. A container for manufacturing mill blanks.
[7] The container for manufacturing a dental mill blank according to any one of [1] to [3], wherein the shape of the composition filling portion in the container is columnar.
[8] The shortest distance Z2 between the inner circumference of the bottom surface of the composition filling portion and the center of gravity Y2 of the specific through hole is the shortest distance between the inner circumference of the bottom surface of the composition filling portion and the center of gravity of the bottom surface of the composition filling portion. The container for manufacturing a dental mill blank according to [7], which has a through hole at a position within 30% of the distance W.
[9] The container for manufacturing a dental mill blank according to [7] or [8], wherein the total number of through holes is two or more.
[10] The container for manufacturing a dental mill blank according to any one of [1] to [9], wherein the material of the container is at least one selected from the group consisting of a thermoplastic resin, a silicone resin, and a metal. ..
[11] The step of filling the curable composition into the container for producing the dental mill blank according to any one of [1] to [10], and pressurizing the curable composition filled in the container. , A method for producing a dental mill blank, comprising a polymerization step of heating the curable composition filled in the container.
[12] The method for producing a dental mill blank according to [11], wherein the pressurizing pressure in the polymerization step is 0.2 to 4.0 MPa and the heating temperature is 60 to 180 ° C.

INDUSTRIAL APPLICABILITY The present invention can improve the filling property of a curable composition into a container when filled with a curable composition having low fluidity, and can improve the yield when manufacturing a dental mill blank. A container for manufacturing a blank and a method for manufacturing a dental mill blank using the container can be provided. Further, the present invention can provide a dental mill blank having few cracks and bubbles and excellent mechanical strength when a curable composition having low fluidity is used. Further, the present invention can improve the filling property of the curable composition into a container even when a highly fluid curable composition is used, and can improve the yield when manufacturing a dental mill blank. A container for manufacturing a mill blank and a method for manufacturing a dental mill blank using the container can be provided. Further, the present invention can provide a dental mill blank having few cracks and bubbles and excellent mechanical strength even when a curable composition having high fluidity is used. Further, in the present invention, a container for manufacturing a dental mill blank, which does not require an operation such as giving a special rotation to the container and can improve the yield when manufacturing a dental mill blank, and dentistry using the container. A method for manufacturing a mill blank can be provided.

FIG. 1 shows a plan view of the bottom surface of the composition filling portion in the case where the composition filling portion of the container for manufacturing a dental mill blank according to the embodiment of the present invention is a polygonal prism. FIG. 2 shows a plan view of the bottom surface of the composition filling portion in the case where the composition filling portion of the container for manufacturing a dental mill blank according to the embodiment of the present invention is cylindrical.

The container for manufacturing a dental mill blank of the present invention is a concave container provided with an opening at the top, and has a wall surface having one or more through holes to the extent that air can pass through, and the opening. It is characterized by comprising a composition filling part containing. As a result, the filling property of the curable composition in the container can be improved, and as a result, the yield in manufacturing the dental mill blank is improved. Further, by using the container, it is possible to provide a dental mill blank having few cracks and bubbles and having excellent mechanical strength. In addition, in this specification, "wall surface" means at least one surface inside a container, and includes "bottom surface" and "side surface". The "bottom surface" may be a surface facing the opening. The recess constitutes the composition filling portion. In one embodiment, the container for manufacturing a dental mill blank according to the present invention has an upper opening, a composition filling portion connected to the opening, and an outside of the container and a composition filling portion. The wall surface has one or more through holes that communicate with and.

The factors that cause this effect are presumed to be as follows, for example. Usually, when a filling container is filled with a hard paste-like curable composition having low fluidity (hereinafter, may be referred to as “paste-like composition”), the paste-like compositions overlap each other in the container. In order to avoid the risk of entraining air at the time, it is common to push and fill the paste-like composition from a nozzle having an inner size equal to or larger than the inner size of the filling container. At this time, the paste filling port of the filling container is closed by the paste-like composition. On the other hand, the container for manufacturing a dental mill blank according to the present invention has one or more through holes on the wall surface, so that the air originally existing in the filling container can be evacuated. For example, in a preferred embodiment, the container for manufacturing a dental mill blank according to the present invention is provided with a structure (composition filling portion) having a through hole on the opposite side to the paste filling port for filling. The air that originally exists in the container can be removed. Further, in the container for manufacturing a dental mill blank according to the present invention, by using a container having through holes formed to the extent that air can pass through, the opening is closed by the filled paste-like composition. Even if this is done, it is presumed that the paste-like composition can be filled without a shortage with respect to the volume of the composition filling portion in the container by allowing air to escape from the through hole provided on the wall surface. For a container for manufacturing a dental mill blank, a method of filling the paste-like composition from a nozzle having an inner size equal to or larger than the inner size of the opening of the filling container is preferable from the viewpoint of avoiding the risk of entraining air. Applies to. On the other hand, since the conventional concave container as described in Patent Document 1 (International Publication No. 2015/045698) does not have a penetrating structure provided with a hole through which air passes, when the opening is closed by the paste-like composition. It is presumed that there is no place for air to escape, and the paste-like composition is pushed back by the repulsion of air, so that it cannot be filled without a shortage with respect to the container volume.

The concave container can be manufactured by a molding method conventionally known in the general industry. For example, vacuum forming method, injection molding, press molding, blow molding, cutting, wire electric discharge machining and the like can be mentioned. Among them, vacuum forming and injection molding are preferably used for soft materials such as thermoplastic resins. For hard materials such as metal, cutting molding and wire electric discharge machining are preferably used.

Further, as a method for forming the through hole, a method known in the general industry can be used. For example, puncher machining, hot needle machining, laser machining, cutting machining, wire electric discharge machining and the like can be mentioned. Among them, puncher processing and laser processing are preferably used for soft materials such as thermoplastic resins. For hard materials such as metal, cutting molding and wire electric discharge machining are preferably used.

The shape of the cross section of the through hole is not particularly limited, but from the viewpoint of ease of forming the through hole, it is preferably formed in a circular shape (round shape, elliptical shape, etc.), and is a perfect circular shape. Is more preferable. The shape of the through hole in the height (depth) direction is not particularly limited as long as it is a through hole through which air can pass, and may be cylindrical, tapered, or the like, but the through hole may be formed. From the viewpoint of ease, a columnar shape is preferable. Further, when the cross-sectional shape of the through hole is circular, it may be a hollow shape in which the central portion is non-penetrating.

The shape of the composition-filled portion in the concave container into which the paste-like composition is filled is a factor that affects the shape of the dental mill blank after curing. The shape of the composition filling portion in the container is not particularly limited, but it is preferably a polygonal prism or a columnar shape from the viewpoint of application to a CAD / CAM system manufactured by cutting with a milling device. Above all, it is more preferable that the columnar shape is a rectangular parallelepiped or a perfect circle. As a container for manufacturing a dental mill blank according to the present invention, if the shape of the composition filling portion in the container is a polygonal prism or a columnar shape, a through hole is used when the paste-like composition is filled from the open port. The effect of air bleeding can be obtained, and the filling property of the curable composition into a container can be improved not only when the curable composition having high fluidity is filled but also when the curable composition having low fluidity is filled. The appearance of the container is not limited to a polygonal prism or a columnar shape because it can be improved and the unfilled volume ratio of the composition-filled portion can be reduced. The container for manufacturing a dental mill blank according to the present invention is, for example, a polygonal prism or a circle having one or more through holes on the bottom surface and communicating the composition filling portion (space) with the outside by the through holes. It may have a shape having a columnar composition filling portion and a thickness on the side surface (for example, a cross-sectional shape such as an egg shape or a star shape when viewed from above).

The position of the through hole is not particularly limited, but when the shape of the composition filling portion of the container is a polygonal prism, the polygonal prism in which the paste-like composition is most difficult to be filled in the space of the composition filling portion. From the viewpoint of facilitating the filling property in the vicinity of the apex of the bottom surface, it is preferable to form a through hole in the vicinity of the apex of the bottom surface. As shown in FIG. 1, specifically, among the vertices of the bottom surface, the distance Z1 between the apex X1 located closest to the specific through hole and the center of gravity Y1 of the through hole forms the apex X1. It is preferable that the through hole is formed so as to be within 30% of the average value of the lengths of the two sides of the bottom surface of the composition filling portion, more preferably 20% or less, still more preferably 15% or less. Further, when the bottom surface has a through hole, a through hole may be further formed on the side surface. In such an embodiment, for example, with respect to the through hole on the bottom surface, the distance Z1 is within 30% of the average value of the lengths of the two sides of the bottom surface of the composition filling portion forming the apex X1, and further on the side surface. Examples thereof include a container for manufacturing a dental mill blank, which comprises a composition filling portion having a through hole.

The position of the through hole is obtained by the following formula. That is, in the present specification, when the shape of the composition filling portion of the container is prismatic, "the through hole is at the position of a ₁ % (for example, 30%)" means that the position of the specific through hole is as follows. It shows that the result of the equation is a ₁ (eg 30).
Position of through hole (%) = 100 × [Distance between the nearest vertex X1 and the center of gravity Y1 of the through hole Z1 (mm) / {(length of side A (mm) + length of side B (mm)) / 2}]

Further, when the shape of the composition filling portion in the container according to the present invention is a polygonal prism or a columnar shape, and the cross-sectional shape of the through hole possessed by the wall surface of the composition filling portion is a circular shape, the diameter of the through hole is formed. Is not particularly limited as long as air can pass through, but when the diameter of the through hole is ( _ra ) mm and the area of the wall surface to which the through hole is provided is (S) mm ² , the following formula (I) is used. And (II) are preferably satisfied.
0.1 ≤ _ra ≤ 5 (I)
S / 10000 ≤ π * (r _a / 2) ² ≤ S / 6 (II)

In other words, the diameter of the through hole is preferably 0.1 to 5 mm, more preferably 0.3 to 4.5 mm, and even more preferably 0.5 to 4 mm. .. When the diameter of the through hole is 0.1 mm or more, the formation of the through hole is facilitated, and the air is easily released, so that the paste-like composition can be obtained without any shortage with respect to the volume of the composition filling portion in the container. Can be filled. Further, since the diameter of the through hole is 5 mm or less, a large amount of the paste-like composition is suppressed from leaking from the through hole, so that it is possible to further reduce the cost increase and the increase in the amount of waste. The area ratio specified in the formula (II) is preferably S / 10000 ≤ π * (r _a / 2) ² ≤ S / 6, and S / 8000 ≤ π * (r _a / 2) ² ≤ S / 15. Is more preferable, and S / 6000 ≤ π * ( _ra / 2) ² ≤ S / 50 is even more preferable. When it is equal to or more than the lower limit of the area ratio specified in the formula (II), the formation of through holes is facilitated and the air is easily released, so that the paste is not insufficient for the volume of the composition filling portion in the container. The state composition can be filled. Further, when the area ratio is not more than the upper limit of the area ratio specified in the formula (II), a large amount of the paste-like composition is suppressed from leaking from the through holes, so that the cost increase and the increase in the amount of waste can be further reduced. Can be done.

Further, in one embodiment, when the shape of the composition filling portion in the container is a polygonal prism and the cross-sectional shape of the through hole is circular, the circular shape in the cross section of the specific through hole is another circular shape existing in the vicinity. And part may overlap. If the circle in the cross section of a particular through hole has a shape that partially overlaps with other circles in the vicinity, it is hard for one of the overlapping circles (preferably the one with the longest diameter). Even if it is a paste-like composition, the distance Z1 between the nearest apex X1 and the circular center of gravity Y1 is easy to fill the paste-like composition without insufficient volume with respect to the volume of the composition filling portion in the container. However, it is preferably within 30%, more preferably within 20%, and even more preferably within 15% of the average value of the lengths of the two sides of the bottom surface of the container forming the apex X1.

As shown in FIG. 2, when the shape of the composition filling portion of the container according to the present invention is columnar, the inner circumference of the composition filling portion where the paste-like composition is most difficult to be filled in the space of the composition filling portion. From the viewpoint of facilitating the filling property in the vicinity, it is preferable to form the composition in the vicinity of the inner circumference of the bottom surface of the filling portion. Specifically, the shortest distance Z2 between the inner circumference of the bottom surface of the composition filling portion and the center of gravity Y2 of the through hole is within 30% of the shortest distance W between the inner circumference of the bottom surface of the composition filling portion and the center of gravity of the bottom surface. It is preferable that the through hole is formed so as to be, 20% or less is more preferable, and 15% or less is further preferable.

The position (%) of the through hole is obtained by the following formula. That is, in the present specification, when the shape of the container is columnar, "the through hole is located at a ₂ % (for example, 30%)" means that the result of the following formula is a for the position of the specific through hole. It shows that it is ₂ (for example, 30). The shortest distance Z2 between the inner circumference of the composition filling portion of the container and the center of gravity Y2 of the through hole is the distance between the center of gravity Y2 of the through hole and the intersection X2 of the perpendicular line from the center of gravity Y2 of the through hole to the circumference.
Position of through hole (%) = 100 × [Shortest distance between the inner circumference of the composition filling part of the container and the center of gravity Y2 of the through hole Z2 (mm) / the inner circumference of the composition filling part of the container and the center of gravity of the bottom surface of the container Shortest distance W (mm)

Further, in one embodiment, when the shape of the composition filling portion in the container is columnar and the cross-sectional shape of the through hole is circular, the circular shape in the cross section of the specific through hole is another circular shape existing in the vicinity. And part may overlap. If a circle in the cross-sectional area of a particular through hole has a shape that partially overlaps with other circles in the vicinity, then for one of the overlapping circles (preferably the one with the longest diameter). The shortest distance Z2 is the inner circumference of the bottom surface of the composition filling portion because it is easy to fill the paste-like composition without a shortage with respect to the volume of the composition filling portion in the container even if it is a hard paste-like composition. It is preferably within 30% of the shortest distance W between the container and the center of gravity of the bottom surface of the container, more preferably within 20%, still more preferably within 15%.

The number of through holes formed is not particularly limited, but it is preferable to form a large number of through holes from the viewpoint of enhancing the air bleeding effect of the through holes. When the shape of the composition filling portion in the container is a polygonal prism and has through holes on the bottom surface, the total number of through holes on the bottom surface is 50% or more of the total number of vertices on the bottom surface of the composition filling portion in the container. It is preferably present, more preferably 75% or more, and even more preferably 100%. The upper limit of the number of through holes is not particularly limited, but can be, for example, 200% or less with respect to the number of vertices of the container. The total number of through holes is the total number on the bottom surface, and the composition filling portion in the container may further have through holes on the side surface. The total number of through holes means the total number of through holes penetrating the bottom surface when the composition filling portion in the container has through holes on the bottom surface. In another embodiment, for example, the shape of the composition filling portion in the container is a polygonal prism, and the distance Z1 between the apex X1 located closest to the specific through hole and the center of gravity Y1 of the through hole is set. , Within 30% of the average value of the lengths of the two sides of the bottom surface of the container forming the apex X1, and further, in addition to the through hole, the wall surface has another through hole whose distance Z1 does not satisfy the range. Examples include containers for manufacturing mill blanks.

When the shape of the composition filling portion in the container is columnar, the total number of through holes on the wall surface having through holes (preferably the bottom surface) is preferably two or more, and preferably three or more. More preferably, it is more preferably four or more. The upper limit of the total number of through holes is not particularly limited, but may be, for example, eight or less. Further, as another embodiment, for example, the shape of the composition filling portion in the container is cylindrical, and the composition filling portion has one or more through holes on a specific wall surface (for example, a bottom surface). The shortest distance Z2 between the inner circumference of the wall surface (for example, the bottom surface) and the center of gravity Y2 of the specific through hole formed in the wall surface is the inner circumference of the wall surface (for example, the bottom surface) of the composition filling portion. , Within 30% of the shortest distance W from the center of gravity of the wall surface (for example, the bottom surface) of the composition filling portion, and further, in addition to the through hole, another through hole (preferably) in which the shortest distance Z2 does not satisfy the above range. Is a container for manufacturing a dental mill blank having a wall surface having a diameter of 0.1 to 5 mm). FIG. 2 shows the shortest distance Z2 and the shortest distance W when the shape of the composition filling portion in the container is cylindrical and the through hole is provided on the bottom surface.

The material of the container for manufacturing a dental mill blank is not particularly limited, but may be, for example, at least one selected from the group consisting of a thermoplastic resin, a silicone resin, and a metal. Among them, a thermoplastic resin or a silicone resin is preferably used, and a thermoplastic resin is more preferably used from the viewpoint of manufacturing cost, dimensional accuracy of the container, and moldability. Examples of the thermoplastic resin include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyvinyl acetate, polytetrafluoroethylene, acrylonitrile butadiene styrene resin, acrylic resin, polysulfone resin, polyphenylsulfone resin and the like. Among these, polypropylene, polytetrafluoroethylene, polysulfone resin, and polyphenylsulfone resin are preferable from the viewpoint of heat resistance and releasability, and polypropylene is more preferable.

In the container for producing a dental mill blank of the present invention, the consistency of the paste-like composition to be filled is low, and even if the paste-like composition is hard, the paste is not insufficient for the volume of the composition filling portion in the container. It is characterized in that it can be filled with a state composition. The consistency of the paste-like composition to be filled in the container is not particularly limited, but is preferably 8 to 50 mm, more preferably 10 to 40 mm, still more preferably 12 to 30 mm. When the consistency is 8 mm or more, it is easy to knead uniformly in the kneading step, or it is possible to easily foam in the defoaming step. Further, since the consistency is 50 mm or less, a large amount of the paste-like composition is suppressed from leaking from the through hole of the container for manufacturing the dental mill blank of the present invention, so that the cost increase and the increase in the amount of waste are further reduced. can do. The method for measuring the consistency is as described in Examples described later. Further, in the present specification, the higher the value, the softer the paste of the composition and the higher the fluidity, and the lower the value, the harder the paste of the composition and the lower the fluidity.

The consistency of the paste-like composition is determined by weighing the paste-like composition on a glass plate, placing the glass plate on the glass plate, and measuring the major axis and the minor axis of the sample after a certain period of time through the glass plate. .. Specific measurement methods will be described in Examples.

The composition of the paste-like composition according to the present invention is not particularly limited, and may include, for example, an inorganic filler (A), a polymerizable monomer (B), and a polymerization initiator (C).

[Inorganic filler (A)]
As the inorganic filler (A) in the present invention, for example, known inorganic particles used as a filler for a dental composite resin can be used. Examples of the inorganic particles include various glasses (for example, silicon dioxide (quartz, quartz glass, silica gel, etc.), silicon as a main component and containing boron and / or aluminum together with various heavy metals), alumina, and various ceramics. Kind, diatomaceous soil, kaolin, clay minerals (montmorillonite, etc.), active white clay, synthetic zeolite, mica, silica, calcium fluoride, itterbium fluoride, calcium phosphate, barium sulfate, zirconium dioxide (zirconia), titanium dioxide (titania), hydroxyapatite And so on. As the inorganic filler, one type may be used alone, or two or more types may be used in combination.

Important physical characteristics desired for dental materials include transparency and X-ray contrast properties similar to those of natural teeth. Of these, transparency can be achieved by matching the refractive indexes of the inorganic filler (A) and the polymer of the polymerizable monomer as much as possible. On the other hand, the X-ray contrast property can be imparted by using an inorganic filler (oxide or the like) containing a heavy metal element such as zirconium, barium, titanium, lanthanum, or strontium as the inorganic filler (A). The refractive index of such an inorganic filler containing a heavy metal element is usually high and is in the range of 1.5 to 1.6. In the present invention, for example, the (meth) acrylic acid ester compound (A) and the mono (meth) having two or more (meth) acryloyloxy groups in one molecule constituting the polymerizable monomer forming the polymer. Since the refractive index of the cured product of the acrylic acid ester compound (B) is usually in the range of 1.5 to 1.6, it is combined with such an inorganic filler having a high refractive index having X-ray contrast property. The difference in refractive index can be adjusted to be small, and the transparency of the obtained dental material can be improved.

Examples of the inorganic filler having a high refractive index capable of imparting the above-mentioned X-ray contrast property include barium borosilicate glass (for example, "E-3000" manufactured by Esstech, "8235" manufactured by Shot, and ". GM27884 "," GM39923 ", etc.), Strontium boroaluminosilicate glass (for example," E-4000 "manufactured by Esstech," G018-093 "," GM32087 "manufactured by Shot, etc.), Lantern glass (for example, Shot). GM31684, etc.), fluoroaluminosilicate glass (eg, Shot's "G018-091", "G018-117", etc.), zirconia-containing glass (eg, Shot's "G018-310"). , "G018-159", etc.), glass containing strontium (eg, "G018-163", "G018-093", "GM32087", etc. manufactured by Shot), glass containing zinc oxide (eg, Shot). (G018-161) etc.), glass containing calcium (for example, “G018-309” etc. manufactured by Shot Co., Ltd.) and the like.

The shape of the inorganic filler (A) is not particularly limited, and various shapes such as crushed, plate-shaped, scaly, fibrous (short fibers, long fibers, etc.), needle-shaped, whiskers, and spherical shapes are used. be able to. The inorganic filler may be a combination of different shapes among the above shapes as long as the requirements of the present invention are satisfied.

The average primary particle size of the inorganic filler (A) in the present invention is not particularly limited, but is preferably 0.01 to 5 μm, more preferably 0.02 μm or more, still more preferably 0.04 μm or more. Further, it is more preferably 3 μm or less, and further preferably 2 μm or less. If the average primary particle size is smaller than 0.01 μm, the mechanical strength is likely to be impaired, and if it is larger than 5 μm, the polishability of the cured product is impaired, and the aesthetics required for dental materials may be deteriorated.

The average primary particle diameter of the inorganic filler (A) can be determined by a laser diffraction / scattering method or electron microscopic observation of the particles. Specifically, the laser diffraction / scattering method is convenient for measuring the particle size of particles having a size of 0.1 μm or more, and electron microscope observation is convenient for measuring the particle size of particles having a size of less than 0.1 μm. A laser diffraction / scattering method may be adopted for determining whether or not the thickness is 0.1 μm or more.

In the laser diffraction / scattering method, for example, a laser diffraction type particle size distribution measuring device (for example, "SALD-2300" manufactured by Shimadzu Corporation) is used as a dispersion medium using a 0.2% sodium hexametaphosphate aqueous solution on a volume basis. The average primary particle size can be obtained by measurement.

In electron microscope observation, for example, an image photograph of a particle scanning electron microscope (SEM; for example, "SU3500H-800NA type" manufactured by Hitachi High-Technologies Corporation) is taken and observed within the unit field of view of the SEM image photograph. The average primary particle size can be obtained by measuring the particle size of particles (200 or more) using an image analysis type particle size distribution measurement software (such as "Mac-View" manufactured by Mountech Co., Ltd.). At this time, the particle diameter of the particles is obtained as a circle-equivalent diameter which is the diameter of a circle having the same area as the area of the particles, and the average primary particle diameter is calculated from the number of particles and the particle diameter.

The content of the inorganic filler (A) in the present invention is preferably 100 to 600 parts by mass, more preferably 150 to 550 parts by mass, and 200 to 500 parts by mass with respect to 100 parts by mass of the polymerizable monomer (B). Parts by mass are more preferred. The content of the inorganic filler (A) in the curable composition according to the present invention is preferably 70% by mass or more, more preferably 72% by mass or more, still more preferably 75% by mass or more. The content of the inorganic filler (A) in the curable composition according to the present invention is preferably 99% by mass or less, more preferably 98% by mass or less, still more preferably 97% by mass or less.

The inorganic filler (A) in the present invention is preferably surface-treated in advance. By using the surface-treated inorganic filler (A), the mechanical strength of the obtained curable composition after curing can be further improved. When two or more kinds of inorganic fillers (A) are used, only one of them may be surface-treated, and all of them may be surface-treated. There may be. In the latter case, the individually surface-treated inorganic filler (A) may be mixed, or a plurality of inorganic fillers may be mixed in advance and the surface treatment may be performed collectively.

As such a surface treatment agent, a known surface treatment agent can be used, and an organic metal compound such as an organic silicon compound, an organic titanium compound, an organic zirconium compound, and an organic aluminum compound, and a phosphoric acid group, a pyrophosphate group, and a thiophosphoric acid can be used. An acidic group-containing organic compound having at least one acidic group such as a group, a phosphonic acid group, a sulfonic acid group, and a carboxylic acid group can be used. When two or more kinds of surface treatment agents are used, it may be used as a surface treatment agent layer of a mixture of two or more kinds of surface treatment agents, or as a surface treatment agent layer having a multi-layer structure in which a plurality of surface treatment agent layers are laminated. good. Further, as the surface treatment method, a known method can be used without particular limitation.

Examples of the organic silicon compound include compounds represented by R ¹ _n SiX _(4-n) (in the formula, R ¹ is a substituted or unsubstituted hydrocarbon group having 1 to 12 carbon atoms, and X is carbon. It indicates an alkoxy group, an acetoxy group, a hydroxyl group, a halogen atom or a hydrogen atom of the number 1 to 4, and n is an integer of 0 to 3, but when there are a plurality of R ¹ and X, they are the same or different. May be).

Specifically, for example, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, etc. Vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, 3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldimethoxysilane, β- (3) , 4-Epoxycyclohexyl) Ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane , Γ-methacryloyloxypropylmethyldiethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ- Aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, trimethylsilanol, methyltrichlorosilane, methyl Dichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, vinyltrichlorosilane, trimethylbromosilane, diethylsilane, vinyltriacetoxysilane, ω- (meth) acryloyloxyalkyltrimethoxysilane [(meth) acryloyl Carbon number between oxy group and silicon atom: 3-12, eg γ-methacryloyloxypropyltrimethoxysilane], ω- (meth) acryloyloxyalkyltriethoxysilane [(meth) acryloyloxy group and silicon atom Number of carbon atoms between: 3 to 12, eg, γ-methacryloyloxypropyltriethoxysilane, etc.] and the like. In the present invention, the notation "(meth) acryloyloxy" is used to include both methacryloyloxy and acryloyloxy.

Among these, a coupling agent having a functional group capable of copolymerizing with a polymerizable monomer, for example, ω- (meth) acryloyloxyalkyltrimethoxysilane [(meth) acryloyloxy group and the number of carbon atoms between the silicon atom: 3-12], ω- (meth) acryloyloxyalkyltriethoxysilane [(meth) carbon number between acryloyloxy group and silicon atom: 3-12], vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri Acetoxysilane, γ-glycidoxypropyltrimethoxysilane and the like are preferably used.

Examples of the organic titanium compound include tetramethyl titanate, tetraisopropyl titanate, tetra n-butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate and the like.

Examples of the organic zirconium compound include zirconium isopropoxide, zirconium n-butoxide, zirconium acetylacetonate, zirconium acetate and the like.

Examples of the organoaluminum compound include aluminum acetylacetonate and aluminum organolate chelate compounds.

Examples of the acidic group-containing organic compound containing a phosphoric acid group include 2-ethylhexyl acid phosphate, stearyl acid phosphate, 2- (meth) acryloyloxyethyl dihydrogen phosphate, 3- (meth) acryloyloxypropyl dihydrogen phosphate, and 4- (meth) acryloyloxybutyl dihydrogen phosphate, 5- (meth) acryloyloxypentyl dihydrogen phosphate, 6- (meth) acryloyloxyhexyl dihydrogen phosphate, 7- (meth) acryloyloxyheptyl dihydrogen Phosphate, 8- (meth) acryloyloxyoctyldihydrogen phosphate, 9- (meth) acryloyloxynonyldihydrogenphosphate, 10- (meth) acryloyloxydecyldihydrogenphosphate, 11- (meth) acryloyloxyundecyl Dihydrogen phosphate, 12- (meth) acryloyl oxide decyl dihydrogen phosphate, 16- (meth) acryloyl oxyhexadecyl dihydrogen phosphate, 20- (meth) acryloyl oxyicosyl dihydrogen phosphate, bis [2- (Meta) acryloyloxyethyl] hydrogen phosphate, bis [4- (meth) acryloyloxybutyl] hydrogen phosphate, bis [6- (meth) acryloyloxyhexyl] hydrogen phosphate, bis [8- (meth) acryloyloxy Octyl] Hydrogen phosphate, Bis [9- (meth) acryloyl oxynonyl] Hydrogen phosphate, Bis [10- (meth) acryloyl oxydecyl] Hydrogen phosphate, 1,3-di (meth) acryloyloxypropyl dihydrogen Phosphate, 2- (meth) acryloyloxyethyl phenylhydrogen phosphate, 2- (meth) acryloyloxyethyl-2-bromoethylhydrogen phosphate, bis [2- (meth) acryloyloxy- (1-hydroxymethyl) ethyl] Examples thereof include hydrogen phosphate, acid acid groups thereof, alkali metal salts, ammonium salts and the like.

Further, as the acidic group-containing organic compound having an acidic group such as a pyrophosphate group, a thiophosphate group, a phosphonic acid group, a sulfonic acid group and a carboxylic acid group, those described in International Publication No. 2012/042911 are preferable. Can be used for.

The above-mentioned surface treatment agent may be used alone or in combination of two or more. Further, an acidic group having a functional group capable of copolymerizing with the polymerizable monomer in order to enhance the chemical bondability between the inorganic filler (A) and the polymerizable monomer and improve the mechanical strength of the cured product. It is more preferable to use the contained organic compound.

The amount of the surface treatment agent used is not particularly limited, and for example, 0.1 to 50 parts by mass is preferable with respect to 100 parts by mass of the inorganic filler (A).

[Polymerizable monomer (B)]
As the polymerizable monomer (B) used in the present invention, for example, a known polymerizable monomer used for a dental composite resin or the like can be used without any limitation, but in general, a radically polymerizable monomer is used. It is preferably used. Specific examples of the radically polymerizable monomer include esters such as α-cyanoacrylic acid, (meth) acrylic acid, α-halogenated acrylic acid, crotonic acid, cinnamic acid, sorbic acid, maleic acid, and itaconic acid; Examples thereof include (meth) acrylamide-based polymerizable monomers such as (meth) acrylamide and (meth) acrylamide derivatives; vinyl esters; vinyl ethers; mono-N-vinyl derivatives; styrene derivatives and the like. Among these, one or more polymerizable monomers selected from the group consisting of (meth) acrylate-based polymerizable monomers and (meth) acrylamide-based polymerizable monomers are preferable, and (meth). Acrylate is more preferred. In the present invention, the notation "(meth) acrylic" is used to include both methacrylic and acrylic, and the notation "(meth) acrylate" is used to include both methacrylate and acrylate. Be done.

(I) Monofunctional (meth) acrylic acid ester and (meth) acrylamide derivative For example, methyl (meth) acrylate, isobutyl (meth) acrylate, benzyl (meth) acrylate, lauryl (meth) acrylate, 2- (N, N-dimethylamino) ethyl (meth) acrylate, 2,3-dibromopropyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, propylene Glycol mono (meth) acrylate, glycerin mono (meth) acrylate, erythritol mono (meth) acrylate, N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N, N-bis (hydroxyethyl) (meth) Acrylamide, (meth) acryloyl oxide decylpyridinium bromide, (meth) acryloyl oxide decylpyridinium chloride, (meth) acryloyloxyhexadecylpyridinium chloride, (meth) acryloyloxydecylammonium chloride, 10-mercaptodecyl (meth) acrylate, o- Phenylphenol (meth) acrylate, m-phenylphenol (meth) acrylate, p-phenylphenol (meth) acrylate, methoxylated-o-phenylphenol (meth) acrylate, methoxylated-m-phenylphenol (meth) acrylate, methoxy Chemicals-p-phenylphenol (meth) acrylates, ethoxylated-o-phenylphenol (meth) acrylates, ethoxylated-m-phenylphenol (meth) acrylates, ethoxylated-p-phenylphenol (meth) acrylates, propoxysylated- o-phenylphenol (meth) acrylate, propoxylated-m-phenylphenol (meth) acrylate, propoxylated-p-phenylphenol (meth) acrylate, butoxylated-o-phenylphenol (meth) acrylate, butoxylated-m- Examples thereof include phenylphenol (meth) acrylate and butoxylated-p-phenylphenol (meth) acrylate.

(Ii) Bifunctional (meth) acrylic acid ester For example, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1 , 6-Hexanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, 2,2-bis [4- [3-acryloyloxy-2-hydroxypropoxy] phenyl] propane, 2,2- Bis [4- [3-methacryloyloxy-2-hydroxypropoxy] phenyl] propane (Bis-GMA), 2,2-bis [4- (meth) acryloyloxyethoxyphenyl] propane, 2,2-bis [4- (Meta) acryloyloxypolyethoxyphenyl] propane, 1,2-bis [3- (meth) acryloyloxy-2-hydroxypropoxy] ethane, pentaerythritol di (meth) acrylate, [2,2,4-trimethylhexamethylene Bis (2-carbamoyloxyethyl)] dimethacrylate (UDM), 2,2,3,3,4,4-hexafluoro-1,5-pentyldi (meth) acrylate and the like can be mentioned.

(Iii) Trifunctional or higher (meth) acrylic acid ester For example, trimethylolpropane tri (meth) acrylate, trimethylolethanetri (meth) acrylate, tetramethylolmethanetri (meth) acrylate, pentaerythritol tetra (meth) acrylate. , Dipentaerythritol hexa (meth) acrylate, N, N'-(2,2,4-trimethylhexamethylene) bis [2- (aminocarboxy) propane-1,3-diol] tetra (meth) acrylate, 1, Examples thereof include 7-diacryloyloxy-2,2,6,6-tetra (meth) acryloyloxymethyl-4-oxaheptane.

As the polymerizable monomer, a cationically polymerizable monomer such as an oxylan compound or an oxetane compound can also be used in addition to the radically polymerizable monomer.

As the polymerizable monomer, one type may be used alone, or two or more types may be used in combination. Further, the polymerizable monomer is preferably in a liquid state, but it does not necessarily have to be in a liquid state at room temperature, and even if it is a solid polymerizable monomer, it is in the form of other liquids. It can also be mixed and dissolved with a monomer before use.

The viscosity (25 ° C.) of the polymerizable monomer is preferably 10 Pa · s or less, more preferably 5 Pa · s or less, and further preferably 2 Pa · s or less. On the other hand, when two or more kinds of polymerizable monomers are mixed and used, or when they are diluted with a solvent and used, the viscosities of the individual polymerizable monomers do not have to be within the above range and are used. In the state (mixed / diluted state), the viscosity is preferably within the above range.

[Polymer Initiator (C)]
Next, the polymerization initiator (C) will be described. The polymerization initiator (C) is roughly classified into a photopolymerization initiator, a thermal polymerization initiator, and a chemical polymerization initiator, and can be uniformly polymerized even if it is thick, or the viscosity of the polymerizable monomer is lowered by heating. A heat polymerization initiator is more preferably used from the viewpoint of increasing the polymerization reaction efficiency and improving the mechanical strength. The thermal polymerization initiator used in the present invention can be selected from the thermal polymerization initiators used in the general industry, and among them, the thermal polymerization initiator used for dental applications is preferably used. Examples of the heat polymerization initiator include organic peroxides and azo compounds.

Examples of the organic peroxides include ketone peroxides, hydroperoxides, diacyl peroxides, dialkyl peroxides, peroxyketals, peroxyesters, peroxydicarbonates and the like.

Examples of the ketone peroxide include methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, methyl cyclohexanone peroxide, cyclohexanone peroxide and the like.

Examples of the hydroperoxide include 2,5-dimethylhexane-2,5-dihydroperoxide, diisopropylbenzenehydroperoxide, cumene hydroperoxide, t-butylhydroperoxide, and 1,1,3,3-tetramethylbutylhydroperoxide. And so on.

Examples of the diacyl peroxide include acetyl peroxide, isobutyryl peroxide, benzoyl peroxide, decanoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, 2,4-dichlorobenzoyl peroxide, and lauroyl peroxide.

Examples of the dialkyl peroxide include di-t-butyl peroxide, dicumyl peroxide, t-butyl cumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, and 1,3-bis. Examples thereof include (t-butylperoxyisopropyl) benzene and 2,5-dimethyl-2,5-di (t-butylperoxy) -3-hexane.

Examples of the peroxyketal include 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, and 2,2-bis (t-). Butane, butane, 2,2-bis (t-butylperoxy) octane, 4,4-bis (t-butylperoxy) valeric acid n-butyl ester and the like can be mentioned.

Examples of the peroxy ester include α-cumylperoxyneodecanoate, t-butylperoxyneodecanoate, t-butylperoxypivalate, and 2,2,4-trimethylpentylperoxy-2-ethylhexanoate. , T-amylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, di-t-butylperoxyisophthalate, di-t-butylperoxyhexahydroterephthalate, t-butylperoxy-3 , 3,5-trimethylhexanoate, t-butylperoxyacetate, t-butylperoxybenzoate, t-butylperoxymaleate and the like.

Examples of the peroxydicarbonate include di-3-methoxyperoxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, diisopropylperoxydicarbonate, and di-n-. Examples thereof include propylperoxydicarbonate, di (2-ethoxyethyl) peroxydicarbonate, and diallylperoxydicarbonate.

Examples of the azo compounds include 2,2'-azobis (isobutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), and 4,4'-azobis (4-cyanovaleric acid). , 1,1'-azobis (cyclohexane-1-carbonitrile), dimethyl-2,2'-azobis (isobutyrate), 2,2'-azobis (2-amidinopropane) dihydrochloride and the like.

Among these heat polymerization initiators, hydroperoxides, peroxyketals, peroxyesters and diacyl peroxides are preferable from the viewpoint of overall balance of safety, storage stability and radical generation ability, and among them, hydroperoxides, peroxyketals and peroxyesters are preferable. Is more preferable. As the heat polymerization initiator, one type may be used alone, or two or more types may be used in combination.

By mixing the polymerizable monomer (B) and the polymerization initiator (C), a polymerizable monomer-containing composition is obtained.

Here, the amount of the polymerization initiator (C) to be blended in the polymerizable monomer-containing composition is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the polymerizable monomer. .. It is more preferably 0.3 to 3 parts by mass, and more preferably 0.5 to 2 parts by mass. If the amount of the polymerization initiator (C) is too small, the unpolymerized component may remain, which may lead to a decrease in strength, and if it is too large, there is a risk of discoloration of the cured product.

In addition to the above-mentioned components, the curable composition of the present invention includes a pH adjuster, an ultraviolet absorber, an antioxidant, a colorant, a pigment, an antibacterial agent, an X-ray contrast agent, a thickener, and a fluorescence, depending on the purpose. It is also possible to further add agents, antifoaming agents and the like.

As the pigment, for example, a known pigment used for a dental composite resin or a dental cement can be used without any limitation. The pigment may be any of an inorganic pigment and / or an organic pigment, and the inorganic pigment may be, for example, a sulphate such as chlorophyll, zinc yellow, barium yellow; a ferrocyanide such as navy blue; silver vermilion, cadmium yellow, etc. Sulfides such as zinc sulfide and cadmium red; sulfates such as barium sulfate, zinc sulfate and strontium sulfate; oxides such as antimony white, zinc flower, titanium white, red iron oxide and chromium oxide; water such as aluminum hydroxide Oxides; silicates such as calcium silicate and ultramarine; carbons such as carbon black and graphite may be mentioned. Examples of the organic pigment include ditron pigments such as Naftor Green B and Naftor Green Y; nitro pigments such as Naftor Yellow S and Resole Fast Yellow 2G; Permanent Red 4R, Brilliant Fast Scarlet, Hansa Yellow, Benzidine Yellow and the like. Insoluble azo pigments; sparingly soluble azo pigments such as resole red, lake red C, lake red D; soluble azo pigments such as Brilliant Carmine 6B, Permanent Red F5R, Pigment Scarlet 3B, Bordeaux 10B; Phtalocyanin pigments such as Sky Blue; basic dye pigments such as Rhodamine Lake, Malakite Green Lake, and Methyl Violet Lake; acidic dye pigments such as Peacock Blue Lake, Eosin Lake, and Kinolin Yellow Lake. The pigment can be used alone or in combination of two or more, and is appropriately selected according to a desired color tone.

The content of the pigment in the curable composition is not particularly limited because it is appropriately adjusted according to a desired color tone, but is preferably 0.000001 parts by mass or more with respect to 100 parts by mass of the curable composition, which is more preferable. Is 0.00001 parts by mass or more, preferably 5 parts by mass or less, and more preferably 1 part by mass or less. The content of the pigment is preferably 0.000001 to 5 parts by mass, and more preferably 0.00001 to 1 part by mass with respect to 100 parts by mass of the curable composition.

The method for producing the curable composition to be filled in the container for producing the dental mill blank of the present invention is not particularly limited, but it is preferable to include the following steps (1) to (3).
(1) A polymerizable monomer-containing composition containing a polymerizable monomer (B) and a polymerization initiator (C) (hereinafter, simply referred to as a “polymerizable monomer-containing composition”), and an inorganic filler ( A) and kneaded at 40 to 60 ° C. to prepare a paste-like composition;
(2) A step of holding the paste-like composition obtained in step (1) at a vacuum degree of 5 to 200 Torr for 3 to 30 minutes;
(3) A step of holding the paste-like composition at a pressure of 0.5 to 5 MPa for 3 to 30 minutes after the step (2).
The above step (1) is a kneading step, and the steps (2) and (3) are a defoaming step, and the detailed procedure thereof will be described below.

[Kneading process]
The kneading step is a step of performing a kneading operation, and a paste-like composition is produced by adding a polymerizable monomer-containing composition and an inorganic filler (A) and kneading them in a kneading machine. In the kneading step, the kneading method is not particularly limited as long as the effect of the present invention is exhibited, and a known method can be adopted. However, from the viewpoint of shortening the kneading time and preventing the occurrence of paste variation, heating is performed. It is preferable to knead while kneading. The kneading temperature is preferably 40 ° C to 60 ° C. When the temperature is 40 ° C. or higher, the effect of shortening the kneading time can be sufficiently obtained. When the kneading temperature is 60 ° C. or lower, it is possible to suppress the occurrence of polymerization curing during kneading. Further, during kneading, vacuum defoaming treatment can be performed if necessary. At this time, the degree of vacuum is not particularly limited, but the degree of vacuum is preferably 5 to 200 Torr in order to efficiently remove air bubbles.

[Defoaming process]
The defoaming step is a step of performing defoaming work, and defoams the paste-like composition by crushing the paste-like composition while applying pressure with a cylinder while removing air bubbles inside the paste by reducing the pressure. Make a bubble. The defoaming conditions are not particularly limited, but the degree of vacuum is preferably 5 to 200 Torr in order to efficiently remove air bubbles and suppress the separation of the polymerizable monomer-containing composition and the inorganic filler (A). The depressurization time as a defoaming condition is preferably 3 to 30 minutes. The pressure at the time of defoaming is preferably 0.5 to 5 MPa. The pressurization time at the time of defoaming is preferably 3 to 30 minutes. In addition, heat treatment can be performed as needed during defoaming. At this time, the temperature is not particularly limited, but the temperature is preferably 35 to 60 ° C. in order to efficiently remove bubbles.

The method for producing a dental mill blank of the present invention is not particularly limited as long as it has a polymerization step of curing the curable composition obtained through the above steps (kneading step, defoaming step) by heat polymerization or the like. , The following steps (4) and (5) are preferably included.
(4) A step of filling the container for producing the dental mill blank of the present invention with the paste-like composition;
(5) A step of placing the container containing the paste-like composition in a chamber capable of having a predetermined pressure as a whole, pressurizing and heating the container, and polymerizing the containers so that the pressures inside and outside the mold become equal.
The above step (4) is a filling step and the step (5) is a polymerization step, and the detailed procedure thereof will be described below.

[Filling process]
The filling step is a step of filling the paste-like composition into a container for manufacturing a dental mill blank for polymerization, and manufacturing a dental mill blank by extruding the paste-like composition from the inside of the defoaming machine container while applying a load with a cylinder. Fill in a container for. The filling conditions are not particularly limited, but the extrusion load by the cylinder is preferably 1 to 100 kN, more preferably 3 to 80 kN, and even more preferably 5 to 50 kN for efficient filling. In addition, heat treatment can be performed as needed during filling. At this time, the temperature is not particularly limited, but the temperature is preferably 35 to 60 ° C. for efficient filling. Further, it is preferable to fill the container for manufacturing a dental mill blank through a nozzle having an inner diameter equal to or larger than the inner diameter (diameter) of the opening of the container so as not to entrain air. The mouth shape is preferably the same as the open mouth shape, and the nozzle inner diameter is more preferably 100 to 120% of the open mouth inner diameter. Within this range, there is no risk of entraining air when the paste-like compositions overlap each other in the container, but the opening is blocked by the paste-like composition and air does not escape from the opening. It is in a state, and the effect of air bleeding by the through hole of the present invention can be further obtained. The inner diameter of the nozzle is more preferably 101 to 115% of the inner diameter of the opening, and further preferably 102 to 110%.

[Polymerization process]
The polymerization step is a step of curing the paste-like composition by a polymerization reaction, and a container filled with the paste-like composition is placed in a chamber capable of having a predetermined pressure as a whole, and pressurized and heated. , Polymerize so that the pressure inside and outside the mold is equal. As this chamber, a pressurized heating container such as an autoclave or a pressure cooker used in the industry can be used. The polymerization conditions are not particularly limited, but the pressure at the time of polymerization is preferably 0.2 to 4.0 MPa, more preferably 0.3 to 2.0 MPa, and even more preferably 0.4 to 0.9 MPa. Within this pressure range, cracks and bubbles can be further suppressed while suppressing the manufacturing cost. The temperature at the time of polymerization is preferably 60 to 180 ° C. Further, from the viewpoint of exhibiting higher mechanical strength, the temperature at the time of polymerization is preferably adjusted to the 10-hour half-life temperature (τ) of the heat polymerization initiator (C), and τ-20 ° C to τ + 30 ° C is more preferable. It is preferable, and more preferably τ-15 ° C to τ + 25 ° C. The holding time in the pressurized heating state at the time of polymerization is preferably 10 to 120 minutes, more preferably 20 to 110 minutes, and even more preferably 30 to 90 minutes. Within this time range, unpolymerized components are unlikely to remain, and polymerization can be performed with higher production efficiency.

The pressure medium during polymerization is not particularly limited, but an inert gas is generally preferably used from the viewpoint of eliminating the influence on the radical polymerization reaction. Specific examples of the inert gas include nitrogen, helium, neon, argon and the like. Among these, nitrogen or argon is preferably used from the viewpoint of production cost, and among them, nitrogen is more preferable. Further, in order to fill the inside of the chamber at the time of polymerization with the inert gas, it is also possible to carry out a replacement operation in which the pressurization and depressurization steps with the inert gas are repeated. At this time, from the viewpoint of the manufacturing cost and the replacement efficiency of the inert gas, it is preferable to lower the pressure of the inert gas to be pressurized at one time and increase the number of replacements. Specifically, the substitution is preferably performed 3 to 15 times at an inert gas pressure of 0.12 to 0.3 MPa, more preferably 5 to 13 times at 0.14 to 0.25 MPa, and 0.15 to 0. It is more preferable to replace with 2 MPa MPa 6 to 12 times. Under the conditions for substituting the inert gas in this range, the residual amount of oxygen, which is an inhibitor of the radical polymerization reaction in the chamber, can be efficiently reduced. As another replacement method, a method of introducing an inert gas after evacuating the inside of the chamber once using a vacuum pump can also be performed.

Further, by heat-treating at a higher temperature after the polymerization curing, the stress strain generated inside the cured product can be alleviated and the mechanical strength can be further improved.

Thus, according to the present invention, it is possible to provide a dental mill blank having improved production yield, few cracks and bubbles, and excellent mechanical strength.

The dental mill blank produced by the present invention can be suitably used as a dental material. Specifically, in the field of dentistry, it can be suitably used as a dental material that can replace a part or the whole of a natural tooth.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Inorganic filler (A)]
UF2.0: Barium borosilicate glass "GM27884 (average primary particle diameter 2.0 μm)" (manufactured by Schott)
UF0.7: Barium borosilicate glass "GM27884 (average primary particle diameter 0.7 μm)" (manufactured by Schott)
NF180: Barium borosilicate glass "GM27884 (average primary particle diameter 0.180 μm)" (manufactured by Schott)
Ox50: Fine particle silica (average primary particle diameter 0.04 μm, manufactured by Nippon Aerosil Co., Ltd.)
[Surface treatment agent]
γ-MPS: γ-methacryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.)
11-MUS: 11-methacryloyl oxide decyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.)

[Polymerizable monomer (B)]
UDMA: [2,2,4-trimethylhexamethylenebis (2-carbamoyloxyethyl)] dimethacrylate (manufactured by Kyoeisha Chemical Co., Ltd.)
D2.6E: 2,2-bis [4-methacryloyloxypolyethoxyphenyl] propane (average number of moles of ethoxy group added: 2.6)
TEGDMA: Triethylene glycol dimethacrylate (manufactured by Shin Nakamura Chemical Industry Co., Ltd.)
NPG: Neopentyl Glycol Dimethacrylate

[Polymer Initiator (C)]
THP: 1,1,3,3-tetramethylbutylhydroperoxide (τ = 152.9 ° C, manufactured by NOF CORPORATION)
BPO: Benzoyl peroxide (τ = 73.6 ° C, manufactured by NOF CORPORATION)

[Container material]
PP: Polypropylene A6061: Aluminum alloy

[Production Example 1 of Inorganic Filler]
A mixture of 80 parts by mass of UF2.0 and 20 parts by mass of NF180 was dispersed in 300 parts by mass of ethanol, and 2.25 parts by mass of γ-MPS, 0.15 parts by mass of acetic acid and 5 parts by mass of water were added for 2 hours at room temperature. Stirred. The solvent was distilled off under reduced pressure and further dried at 90 ° C. for 3 hours to perform surface treatment to obtain an inorganic filler (F1).

[Production Example 2 of Inorganic Filler]
A mixture of 90 parts by mass of UF 0.7 and 10 parts by mass of Ox50 was dispersed in 300 parts by mass of ethanol, 6 parts by mass of γ-MPS, 0.15 parts by mass of acetic acid and 5 parts by mass of water were added, and the mixture was stirred at room temperature for 2 hours. .. The solvent was distilled off under reduced pressure and further dried at 90 ° C. for 3 hours to perform surface treatment to obtain an inorganic filler (F2).

[Production Example 3 of Inorganic Filler]
100 parts by mass of NF180 was dispersed in 300 parts by mass of ethanol, 11 parts by mass of 11-MUS, 0.15 parts by mass of acetic acid and 5 parts by mass of water were added, and the mixture was stirred at room temperature for 2 hours. The solvent was distilled off under reduced pressure and further dried at 90 ° C. for 3 hours to perform surface treatment to obtain an inorganic filler (F3).

A production example of each inorganic filler is shown in Table 2 below.

[Production Example 1 (M1) of Polymerizable Monomer-Containing Composition]
A polymerizable monomer-containing composition (M1) was prepared by dissolving 1 part by mass of THP as a polymerization initiator in 97 parts by mass of UMDA and 3 parts by mass of NPG.

[Production Example 2 (M2) of Polymerizable Monomer-Containing Composition]
A polymerizable monomer-containing composition (M2) was prepared by dissolving 1 part by mass of THP as a polymerization initiator in 97 parts by mass of D2.6E and 3 parts by mass of NPG.

[Production Example 3 (M3) of Polymerizable Monomer-Containing Composition]
A polymerizable monomer-containing composition (M3) was prepared by dissolving 1 part by mass of BPO as a polymerization initiator in 70 parts by mass of UMDA and 30 parts by mass of TEGDMA.

[Production Example 4 (M4) of Polymerizable Monomer-Containing Composition]
A polymerizable monomer-containing composition (M4) was prepared by dissolving 1 part by mass of THP as a polymerization initiator in 70 parts by mass of D2.6E and 30 parts by mass of TEGDMA.

Example 1
A polypropylene sheet having a thickness of 1 mm was vacuum-formed to obtain a concave container having an inner dimension of 15 mm × 15 mm and a depth of 20 mm and having a rectangular parallelepiped shape of the inner surface of the container (the shape of the composition filling portion). The concave container does not have one of the wall surfaces of a rectangular parallelepiped, and is a concave container having this portion as an open opening. Hereinafter, the open opening portion is referred to as an "upper open opening". Next, four through holes having a diameter of 1 mm (circular cross-sectional shape) were formed on the bottom surface by punching. Here, the bottom surface means a wall surface facing the upper opening. Each of the through holes exists at a position 5% from each apex located closest to the bottom surface (inner dimension: 15 mm × 15 mm). The inorganic filler and the polymerizable monomer-containing composition shown in Tables 1 and 2 were mixed and kneaded to make them uniform, and then vacuum defoamed to obtain a paste-like curable composition. The resulting paste-like curable composition was placed in a cartridge connected to a filling nozzle having an inner size of 16 mm × 16 mm. A load of 20 kN is applied to the paste-like curable composition using a cylinder installed on the upper part of the cartridge, and the paste-like curable composition is applied through a filling nozzle connected to the lower part of the cartridge. Was filled in a concave container. After that, a concave container filled with the paste-like composition was fixed in a chamber of an autoclave (manufactured by Kyoshin Engineering Co., Ltd.), and nitrogen having a concentration of 99.9% was replaced 12 times at 0.15 MPa to adjust the oxygen concentration. It was set to less than 1000 ppm. In addition, ppm means vol ppm. Then, the pressure was increased to 0.4 MPa with nitrogen, and at the same time as the pressure increase was completed, the temperature inside the chamber was raised to 130 ° C. and held for 60 minutes to polymerize and cure. The polymerized dental mill blank was removed from the container. The following characteristic evaluation tests (Test Examples 1 to 4) were carried out on the obtained dental mill blank. The results are shown in Table 3.

Examples 2-7, 10, 12
A polypropylene sheet having a thickness of 1 mm is vacuum-formed, and the shape of the inner surface of the container (the shape of the composition filling portion) is a rectangular parallelepiped concave shape having an inner dimension of 15 mm × 15 mm and a depth of 20 mm, as in Example 1. Obtained a container. Next, puncher processing was performed to form through holes having the diameters shown in Table 3 at the positions and quantities shown in Table 3. The inorganic filler and the polymerizable monomer-containing composition shown in Tables 1 and 2 were mixed and kneaded to make them uniform, and then vacuum defoamed to obtain a paste-like curable composition. The obtained paste-like curable composition was placed in a filling nozzle having an inner dimension of 16 mm × 16 mm, the upper opening of the concave container was connected to the nozzle mouth, and a load of 20 kN was applied using a cylinder. The container was filled. After that, the concave container filled with the paste-like composition was fixed in the chamber of an autoclave (manufactured by Kyoshin Engineering Co., Ltd.), and nitrogen having a concentration of 99.9% was replaced 12 times at 0.15 MPa to reduce the oxygen concentration to 1000 ppm. Less than. Then, the pressure was increased to 0.4 MPa with nitrogen, and at the same time as the pressure increase was completed, the temperature inside the chamber was raised to 130 ° C. and held for 60 minutes to polymerize and cure. The polymerized dental mill blank was removed from the container. The following characteristic evaluation tests (Test Examples 1 to 4) were carried out on the obtained dental mill blank. The results are shown in Table 3.

Example 8
A polypropylene sheet having a thickness of 1 mm was vacuum-formed to obtain a concave container having a regular triangular columnar shape (the shape of the composition filling portion) on the inner surface of the container having a side of 15 mm and a depth of 20 mm. Next, three through holes having a diameter of 1 mm were formed on the bottom surface by punching. Each of the through holes exists at a position 5% from each apex located closest to the bottom surface (inner dimension: 15 mm × 15 mm). The inorganic filler and the polymerizable monomer-containing composition shown in Tables 1 and 2 were mixed and kneaded to make them uniform, and then vacuum defoamed to obtain a paste-like curable composition. The obtained paste-like curable composition was placed in a filling nozzle having a regular triangular inner dimension with a side of 16 mm, the upper opening of the concave container was connected to the nozzle mouth, and a cylinder was used to make 20 kN. The container was filled while applying a load. After that, the concave container filled with the paste-like composition was fixed in the chamber of an autoclave (manufactured by Kyoshin Engineering Co., Ltd.), and nitrogen having a concentration of 99.9% was replaced 12 times at 0.15 MPa to reduce the oxygen concentration to 1000 ppm. Less than. Then, the pressure was increased to 0.4 MPa with nitrogen, and at the same time as the pressure increase was completed, the temperature inside the chamber was raised to 130 ° C. and held for 60 minutes to polymerize and cure. The polymerized dental mill blank was removed from the container. The following characteristic evaluation tests (Test Examples 1 to 4) were carried out on the obtained dental mill blank. The results are shown in Table 3.

Example 9
Aluminum alloy (A6061) is wire electric discharge machined and molded, and the inner dimensions are 15 mm × 15 mm and the depth is 20 mm, and the shape of the inner surface of the container (shape of the composition filling portion) is rectangular parallelepiped, as in Example 1. A concave container was obtained. Next, four through holes having a diameter of 1 mm were formed on the bottom surface by wire electric discharge machining. Each of the through holes is located 5% from each of the closest vertices. The inorganic filler and the polymerizable monomer-containing composition shown in Tables 1 and 2 were mixed and kneaded to make them uniform, and then vacuum defoamed to obtain a paste-like curable composition. The obtained paste-like curable composition was placed in a filling nozzle having an inner dimension of 16 mm × 16 mm, the upper opening of the concave container was connected to the nozzle mouth, and a load of 20 kN was applied using a cylinder. The container was filled. After that, the concave container filled with the paste-like composition was fixed in the chamber of an autoclave (manufactured by Kyoshin Engineering Co., Ltd.), and nitrogen having a concentration of 99.9% was replaced 12 times at 0.15 MPa to reduce the oxygen concentration to 1000 ppm. Less than. Then, the pressure was increased to 0.4 MPa with nitrogen, and at the same time as the pressure increase was completed, the temperature inside the chamber was raised to 130 ° C. and held for 60 minutes to polymerize and cure. The polymerized dental mill blank was removed from the container. The following characteristic evaluation tests (Test Examples 1 to 4) were carried out on the obtained dental mill blank. The results are shown in Table 3.

Example 11
A polypropylene sheet having a thickness of 1 mm is vacuum-formed, and the shape of the inner surface of the container (the shape of the composition filling portion) is a rectangular parallelepiped concave shape having an inner dimension of 15 mm × 15 mm and a depth of 20 mm, as in Example 1. Obtained a container. Next, four through holes having a diameter of 1 mm were formed on the bottom surface by punching. Each of the through holes is located 5% from each of the closest vertices. The inorganic filler and the polymerizable monomer-containing composition shown in Tables 1 and 2 were mixed and kneaded to make them uniform, and then vacuum defoamed to obtain a paste-like curable composition having 16 mm ×. The container was placed in a filling nozzle having an inner dimension of 16 mm, the upper opening of the concave container was connected to the nozzle port, and the container was filled while applying a load of 20 kN using a cylinder. After that, the concave container filled with the paste-like composition was fixed in the chamber of an autoclave (manufactured by Kyoshin Engineering Co., Ltd.), and nitrogen having a concentration of 99.9% was replaced 12 times at 0.15 MPa to reduce the oxygen concentration to 1000 ppm. Less than. Next, the pressure was increased to 0.4 MPa with nitrogen, and at the same time as the pressure was completed, the temperature inside the chamber was raised to 80 ° C. and held for 60 minutes to polymerize and cure. The polymerized dental mill blank was removed from the container. The following characteristic evaluation tests (Test Examples 1 to 4) were carried out on the obtained dental mill blank. The results are shown in Table 3.

Example 13
A polypropylene sheet having a thickness of 1 mm was vacuum formed to obtain a concave container having an inner diameter of φ15 mm and a depth of 20 mm and having a cylindrical inner surface (shape of the composition filling portion). Next, four through holes having a diameter of 1 mm were formed on the bottom surface by punching. Each of the through holes exists at a position 5% from the inner peripheral portion of the nearest bottom surface on the bottom surface (inner diameter: φ15 mm). The inorganic filler and the polymerizable monomer-containing composition shown in Tables 1 and 2 were mixed and kneaded to make them uniform, and then vacuum defoamed to obtain a paste-like curable composition. The obtained paste-like curable composition is placed in a filling nozzle having a circular inner dimension with an inner diameter of φ16 mm, the upper opening of the concave container is connected to the nozzle mouth, and a load of 20 kN is used using a cylinder. The container was filled with water. After that, the concave container filled with the paste-like composition was fixed in the chamber of an autoclave (manufactured by Kyoshin Engineering Co., Ltd.), and nitrogen having a concentration of 99.9% was replaced 12 times at 0.15 MPa to reduce the oxygen concentration to 1000 ppm. Less than. Then, the pressure was increased to 0.4 MPa with nitrogen, and at the same time as the pressure increase was completed, the temperature inside the chamber was raised to 130 ° C. and held for 60 minutes to polymerize and cure. The polymerized dental mill blank was removed from the container. The following characteristic evaluation tests (Test Examples 1 to 4) were carried out on the obtained dental mill blank. The results are shown in Table 3.

Comparative Example 1
A polypropylene sheet having a thickness of 1 mm was vacuum-formed to obtain a concave container having a rectangular parallelepiped inner surface having an inner dimension of 15 mm × 15 mm and a depth of 20 mm, as in Example 1. The inorganic filler and the polymerizable monomer-containing composition shown in Tables 1 and 2 were mixed and kneaded to make them uniform, and then vacuum defoamed to obtain a paste-like curable composition. The obtained paste-like curable composition was placed in a filling nozzle having an inner dimension of 16 mm × 16 mm, and the upper opening and the nozzle opening of the concave container having no through hole were connected to each other, and a cylinder was used. The container was filled with a load of 20 kN. After that, the concave container filled with the paste-like composition was fixed in the chamber of an autoclave (manufactured by Kyoshin Engineering Co., Ltd.), and nitrogen having a concentration of 99.9% was replaced 12 times at 0.15 MPa to reduce the oxygen concentration to 1000 ppm. Less than. Then, the pressure was increased to 0.4 MPa with nitrogen, and at the same time as the pressure increase was completed, the temperature inside the chamber was raised to 130 ° C. and held for 60 minutes to polymerize and cure. The polymerized dental mill blank was removed from the container. The following characteristic evaluation tests (Test Examples 1 to 4) were carried out on the obtained dental mill blank. The results are shown in Table 3.

Comparative Example 2
The inorganic filler (F1) and the polymerizable monomer-containing composition (M1) are mixed and kneaded at the composition ratios shown in Table 3 to make them uniform, and then vacuum defoamed to produce a paste-like curable composition. did. Next, the concave container having no through hole described in Comparative Example 1 is manually filled, mounted on a rotating revolution type agitator (manufactured by Sugino Machine Limited), and stirred at a revolution speed of 1090 rpm and a rotation speed of 970 rpm for 120 seconds. did. After that, the container filled with the curable composition was fixed in an autoclave (manufactured by Kyoshin Engineering Co., Ltd.), and nitrogen having a concentration of 99.9% was replaced 12 times at 0.15 MPa to reduce the oxygen concentration to less than 1000 ppm. .. Then, the pressure was increased to 0.4 MPa with nitrogen, and at the same time as the pressure increase was completed, the temperature inside the furnace was raised to 130 ° C. and polymerized and cured for 1 hour. The polymerized dental mill blank was removed from the container. The following characteristic evaluation tests (Test Examples 1 to 4) were carried out on the obtained dental mill blank. The results are shown in Table 3.

Test Example 1 [Consistency]
The produced curable composition was allowed to stand in a constant temperature room (humidity 50%) at 25 ° C. for 1 day, and then 0.5 mL of the paste of the curable composition was weighed as a sample on a glass plate. A PET film (5 cm × 5 cm) was placed on it, and a load of 1 kg was applied from above. The major axis and the minor axis of the sample after 30 seconds were measured through a glass plate, and the arithmetic mean of both was calculated and used as the consistency (mm) (n = 2). The measured average values are shown in Table 3. The lower the consistency, the harder the paste is, and it is judged that the paste is hard at 18 mm or less, further hard at 15 mm or less, and very hard at 12 mm or less.

Test Example 2 [Fillability]
The filling property of the produced curable composition into the container described in Examples and Comparative Examples was evaluated by the following method. That is, the volume of the container was measured using a 3D scanner type coordinate measuring machine (VL-500, manufactured by KEYENCE CORPORATION). Next, the volume of the dental mill blank manufactured using the container was measured using a 3D scanner type coordinate measuring machine (VL-500, manufactured by KEYENCE CORPORATION) (n = 10). The measured average values are shown in Table 3. Then, the unfilled volume fraction was calculated by the following formula. The unfilled volume ratio indicates the ratio of the volume inside the container in which the curable composition is not filled, and is preferably 5% or less, more preferably 3% or less, still more preferably 1% or less.
Unfilled volume ratio (%) = 100 × {(container volume (cm ³ ) -dental mill blank volume (cm ³ ))} / container volume (cm ³ )

Test Example 3 [Rhagades and bubble generation rate]
For the manufactured dental mill blanks of each example and each comparative example, cracks in the inside and outside of the dental mill blank were used using a desktop microfocus X-ray CT system (manufactured by Shimadzu Corporation, inspeXio SMX-90CT). And the presence or absence of air bubbles was evaluated (n = 10). As an evaluation of the bubble generation rate of the cured product, the number of the cured product having bubbles is preferably 1 or less, and most preferably 0. On the other hand, if the number is three or more, it is judged that the quality is poor from the viewpoint of deterioration of mechanical strength and deterioration of appearance.

Test Example 4 [Bending test]
The bending strength of the manufactured dental mill blanks of each example and each comparative example was measured by the following method. That is, a test piece (1.2 mm × 4 mm × 14 mm) was prepared from the manufactured dental mill blank using a diamond cutter, and polished with # 2000 abrasive paper. After immersing this in water at 37 ° C for 1 month (after immersing in water at 37 ° C (1 month)), set it in a universal testing machine (manufactured by Shimadzu Corporation) and crosshead speed. The bending strength was measured by a three-point bending test method under the conditions of 1 mm / min and a distance between fulcrums of 12 mm (n = 10). The measured average values are shown in Table 3. The bending strength is preferably 250 MPa or more, more preferably 270 MPa or more, further preferably 280 MPa or more, and particularly preferably 290 MPa or more without immersion. The bending strength is preferably 200 MPa or more, more preferably 220 MPa or more, and even more preferably 240 MPa or more after immersion in water at 37 ° C. (1 month).

It was found that the dental mill blanks obtained in Examples 1 to 13 had a low unfilled volume ratio, excellent filling property, few defects such as cracks and bubbles, and high mechanical strength. Further, even when the paste of the curable composition is soft and has high fluidity as in Example 12, the obtained dental mill blank has a low unfilled volume fraction and excellent filling property, and has cracks and cracks. It was found that there were few defects such as bubbles and it had high mechanical strength. On the other hand, the dental mill blank obtained in Comparative Example 1 had a high unfilled volume fraction and could not be filled to the bottom surface of the container, resulting in many cracks and low mechanical strength. Further, in Comparative Example 2, the polymerizable monomer was separated on the surface of the curable composition after the rotation / revolution type stirrer. Further, the dental mill blank obtained after the polymerization curing had many bubbles remaining, and the mechanical strength was remarkably low due to the separation of the polymerizable monomer.

From the above results, the method for manufacturing a dental mill blank using the container for manufacturing a dental mill blank of the present invention is effective in improving the yield, and the dental mill blank manufactured by the manufacturing method has cracks and bubbles. It was found that there were few defects such as, and it had high mechanical strength.

The container for manufacturing a dental mill blank of the present invention and the method for manufacturing a dental mill blank using the same are effective in improving the yield, and the dental mill blank manufactured by the manufacturing method has cracks, bubbles, etc. Has few defects and has excellent mechanical strength. That is, it has sufficient mechanical strength to replace natural teeth, and is suitably used as a material for repairing tooth defects and caries.

1 Container for manufacturing dental mill blanks 2 Through holes 3 Sides A
4 sides B
X1 Vertex where the through hole is closest The shortest distance between the inner circumference of the bottom surface of the filling part and the center of gravity of the bottom surface of the container

Claims (12)

A container for making a dental mill blank for filling a paste-like curable composition.
It has an opening above the container and has an opening.
A container for manufacturing a dental mill blank, wherein the container includes a wall surface having one or more through holes and a composition filling portion including the opening. The container for manufacturing a dental mill blank according to claim 1, wherein the cross-sectional shape of the through hole is circular. The invention according to claim 1 or 2, wherein the following formulas (I) and (II) are satisfied when the diameter of the through hole is ( _ra ) mm and the area of the wall surface having the through hole is (S) mm ² . A container for manufacturing dental mill blanks.
0.1 ≤ _ra ≤ 5 (I)
S / 10000 ≤ π * (r _a / 2) ² ≤ S / 6 (II) The container for manufacturing a dental mill blank according to any one of claims 1 to 3, wherein the shape of the composition filling portion in the container is a polygonal prism. The wall surface is a bottom surface, and the distance Z1 between the apex X1 located closest to a specific through hole and the center of gravity Y1 of the through hole among the vertices of the bottom surface forms the apex X1. The container for manufacturing a dental mill blank according to claim 4, which has the through hole at a position within 30% of the average value of the lengths of the two sides of the bottom surface of the above. The dental mill blank for manufacturing according to claim 4 or 5, wherein the wall surface having the through holes is a bottom surface, and the total number of through holes on the bottom surface is 50% or more with respect to the total number of vertices on the bottom surface. container. The container for manufacturing a dental mill blank according to any one of claims 1 to 3, wherein the shape of the composition filling portion in the container is columnar. The shortest distance Z2 between the inner circumference of the bottom surface of the composition filling portion and the center of gravity Y2 of the specific through hole is the shortest distance W between the inner circumference of the bottom surface of the composition filling portion and the center of gravity of the bottom surface of the composition filling portion. The container for manufacturing a dental mill blank according to claim 7, which has a through hole at a position within 30%. The container for manufacturing a dental mill blank according to claim 7 or 8, wherein the total number of through holes is two or more. The container for manufacturing a dental mill blank according to any one of claims 1 to 9, wherein the material of the container is at least one selected from the group consisting of a thermoplastic resin, a silicone resin, and a metal. The step of filling the curable composition into the container for producing a dental mill blank according to any one of claims 1 to 10, and the curable composition filled in the container are pressurized to press the container. A method for producing a dental mill blank, comprising a polymerization step of heating a curable composition packed in a. The method for producing a dental mill blank according to claim 11, wherein the pressurizing pressure in the polymerization step is 0.2 to 4.0 MPa, and the heating temperature is 60 to 180 ° C.

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