JP2016174683A - Crucible former - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crucible former capable of forming a casting mold inhibiting chip from being formed on a bottom part of a sprue when pressingly molding a ceramic blank.SOLUTION: The crucible former for use in production of a ceramic dental prosthesis includes a wax pattern setting part. The wax pattern setting part includes a columnar-shape part having a columnar shape, and a diameter-reducing part that is provided adjacent to the columnar-shape part along the longitudinal direction of the wax pattern setting part and, of which a diameter of a surface perpendicular to the longitudinal direction of the wax pattern setting part decreases towards the end of the wax pattern setting part.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a crucible former.

  When a part of a tooth is removed or lost due to a dental treatment or the like, since the tooth cannot naturally recover the removed part or the missing part, a dental prosthesis is placed on the removed part or the missing part. . Conventionally, metals have been used as materials for dental prostheses, but ceramic dental prostheses are increasingly used from the viewpoint of aesthetics.

  A ceramic dental prosthesis is produced, for example, by the following procedure.

  First, a wax pattern molded into a shape corresponding to the dental prosthesis to be formed is inserted into a crucible former (wax model plant for mold production of a dental prosthesis) through a sprue wire molded into a shape corresponding to a sprue line portion described later. It is fixed to a standing tool and buried in the investment material. Then, after the investment material is cured, the crucible former is removed and the wax pattern and the sprue wire are incinerated to form a mold.

  The crucible former has a cylindrical portion corresponding to the shape of the pouring gate of the mold, and the wax pattern is fixed to the cylindrical portion via a sprue line. Then, when the wax pattern is embedded in the investment material, the cylindrical portion of the crucible former is also embedded in the investment material. For this reason, for example, as schematically shown in FIG. 1, a gap 11 having a shape corresponding to a dental prosthesis and a gate 13 communicating with the sprue line portion 12 can be formed in the mold.

  After forming the mold, as shown in FIG. 1, the ceramic blank 14 can be placed in the gate 13 formed by the crucible former and heated, and the ceramic blank 14 can be pressed by, for example, the piston 15. As a result, the ceramic material constituting the ceramic blank 14 is filled into the gap 11 having a shape corresponding to the dental prosthesis from the sprue 13 through the sprue portion 12, and the ceramic dental prosthesis having a desired shape. Can be manufactured.

  For example, Patent Document 1 discloses that a ceramic score is formed by heating and softening a ceramic body and then pressing and injecting the ceramic body into a mold. In Patent Document 1, a crucible former in which a columnar body having a fitting recess provided in the center of the upper surface is formed at the center of a bottomed cylindrical body, and a solid lubricant is applied to the surface attached to the fitting recess. The crucible former is removed from the assembly of the wax pattern, the ring with the back layer material engaged with the bottomed cylinder, and the investment material filled and hardened between the ring and the tooth model. It is disclosed that a ceramic score is formed by using a mold formed by incineration of a pattern, filling a ceramic body in a portion corresponding to a former columnar body of the mold, and pressing the ceramic body with a plunger.

  By the way, although the ceramic blank is softened by heating, the fluidity is low unlike the molten metal in which the metal is dissolved. Therefore, in order to fill the gap 11 having a shape corresponding to the dental prosthesis with the ceramic material constituting the ceramic blank 14 disposed in the gate 13 as described above, the ceramic blank 14 is heated and pressurized by the piston 15. It is necessary to do together.

  For this reason, the shape of the gate 13 formed in the mold used when manufacturing the dental prosthesis made of ceramics is a cylindrical shape in accordance with the shape of the piston 15. Moreover, the part corresponding to the gate of the crucible former and the ceramic blank arranged in the gate were made cylindrical.

International Publication No. 01/021088

  However, when the ceramic blank 14 is placed in the cylindrical gate 13 and press-molded, “chips” may occur in the bottom 13a of the gate 13 and the like.

  When the chipping occurs, there is a possibility that the fragment of the investment material that has constituted the bottom of the gate is mixed into the dental prosthesis, which is not preferable from the viewpoint of aesthetics and the prevention of strength reduction. In some cases, it is necessary to prepare the wax pattern again, which is problematic in terms of productivity and economy.

  The present invention has been made in view of the above-described problems of the prior art, and according to one aspect of the present invention, a crucible foam capable of forming a mold that suppresses the occurrence of chipping at the bottom of the gate when a ceramic blank is press-molded. The purpose is to provide merchants.

According to one aspect of the present invention, a crucible former used for manufacturing a dental prosthesis made of ceramics, having a wax pattern planting portion,
The wax pattern planting part is
A cylindrical portion having a cylindrical shape;
A surface that is provided adjacent to the cylindrical portion along the longitudinal direction of the wax pattern planting portion and that is perpendicular to the longitudinal direction of the wax pattern planting portion toward the end of the wax pattern planting portion. A crucible former including a reduced diameter portion having a reduced diameter is provided.

  According to one aspect of the present invention, it is possible to provide a crucible former capable of forming a mold that suppresses the occurrence of chipping at the bottom of a gate when press-molding a ceramic blank.

Explanatory drawing of the conventional method at the time of press-molding a ceramic blank with a casting_mold | template. Explanatory drawing of the crucible former in embodiment of this invention. Explanatory drawing of the other structural example of the wax pattern planting part in embodiment of this invention. Explanatory drawing (the 1) of the manufacturing method of the dental prosthesis in embodiment of this invention. Explanatory drawing of the manufacturing method of the dental prosthesis in embodiment of this invention (the 2).

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described. However, the present invention is not limited to the following embodiments, and various modifications and changes can be made to the following embodiments without departing from the scope of the present invention. Substitutions can be added.
[Crucible former]
In the present embodiment, a configuration example of the crucible former will be described.

  The crucible former of this embodiment relates to a crucible former used for manufacturing a dental prosthesis made of ceramics.

  The crucible former of this embodiment can have a wax pattern planting portion. And the wax pattern planting part is provided adjacent to the columnar part along the longitudinal direction of the columnar part having a columnar shape and the wax pattern planting part, toward the end of the wax pattern planting part In addition, a reduced diameter portion in which the diameter of the surface perpendicular to the longitudinal direction of the wax pattern planting portion is reduced can be included.

  As described above, in the conventional technique, when the ceramic blank is press-molded, there is a case where a chip or the like of a mold spout produced using a crucible former is chipped. When chipping occurred, there was a possibility that a fragment of the investment material that had constituted the bottom of the gate would be mixed into the dental prosthesis, which was not preferable from the viewpoint of aesthetics and strength. In some cases, it is necessary to prepare the wax pattern again, which is problematic in terms of productivity and economy.

  The inventors of the present invention have intensively studied the cause of chipping at the bottom of the mold gate and the like and the method for suppressing the chipping when the ceramic blank is press-molded in the prior art.

  First, in the prior art, when producing a dental prosthesis made of ceramics, a ceramic blank is placed in a mold gate and press-molded, so the shape of the mold gate is that of the piston 15 as shown in FIG. The shape is cylindrical according to the shape, and the bottom 13a of the gate 13 is a flat surface. And even if the ceramic blank 14 was heated, fluidity | liquidity was low, and since the bottom part 13a of the gate 13 was flat as mentioned above, the ceramic blank 14 did not flow easily to the sprue line part 12. For this reason, when pressure was applied to the ceramic blank 14 with the piston 15 for press molding, it discovered that big force was added with respect to the bottom part 13a of the gate 13, and the bottom part 13a had a chip.

  Therefore, the inventors of the present invention can solve the conventional problem by using a crucible former that can form a sprue with a shape that allows the ceramic blank to easily flow to the sprue line portion when the ceramic blank is press-molded. The headline and the present invention were completed.

  A configuration example of the crucible former according to the present embodiment will be described with reference to the drawings.

  FIG. 2 shows an example of the configuration of the crucible former of this embodiment. FIG. 2A schematically shows a cross-sectional view of a plane passing through the central axis of the crucible former 20 and parallel to the central axis. FIG. 2B shows a view of the crucible former 20 as viewed from the upper side of the surface on which the wax pattern planting portion 21 is formed, and is a cross section taken along the line AA ′ in FIG. The figure corresponds to the figure shown in FIG.

  As shown in FIGS. 2A and 2B, the crucible former 20 of the present embodiment can have a rod-shaped wax pattern planting portion 21.

  The wax pattern planting portion 21 can include a columnar portion 211 and a reduced diameter portion 212.

  The columnar portion 211 has a columnar shape. Accordingly, the cylindrical portion 211 has a cross-sectional diameter c on a plane (XY plane) perpendicular to the Z axis at an arbitrary position in the longitudinal direction of the wax pattern planting portion 21, that is, in the Z axis direction in FIG. Is constant.

  The reduced diameter portion 212 is provided adjacent to the cylindrical portion 211 along the longitudinal direction of the wax pattern planting portion 21. Then, a cross section in a plane (XY plane) perpendicular to the longitudinal direction of the wax pattern planting portion 21 in the Z-axis direction in the figure from the end of the cylindrical portion 211 toward the end 21a side of the wax pattern planting portion 21 The diameter of is smaller. That is, the reduced diameter portion 212 is configured such that the diameter of the cross section is reduced toward the end portion 21 a side of the wax pattern planting portion 21.

  In addition, the edge part 21a of the wax pattern planting part 21 refers to the wax pattern planting part 21 in the investment material for producing a dental prosthesis out of both longitudinal ends of the wax pattern planting part 21. It is arranged on the investment material side when burying, and means the end on the side forming the bottom of the gate. Further, the end portion 21a of the wax pattern planting portion 21 is not connected to other members such as a base portion 23 described later among both end portions in the longitudinal direction (Z-axis direction) of the wax pattern planting portion 21. It can also be said to be the end of the free end.

  When forming a mold for producing a dental prosthesis, the wax pattern planting portion functions not only as a fixing member for fixing the wax pattern but also as a mold for forming a mold gate. According to the study of the inventors of the present invention, when the shape of the pouring gate of the formed mold is press-molded with the ceramic blank placed in the pouring gate, the ceramic material constituting the ceramic blank flows into the sprue wire portion. An easy shape is preferable from the viewpoint of solving the problem.

  Therefore, the crucible former of the present embodiment has a columnar portion on the wax pattern planting portion, and is perpendicular to the longitudinal direction of the wax pattern planting portion from the end of the columnar portion toward the end of the wax pattern planting portion. It is possible to provide a reduced diameter portion in which the diameter of the smooth surface is reduced. As described above, a reduced diameter portion is provided at the end corresponding to the bottom of the gate of the wax pattern planting portion, and the shape of the bottom of the gate is formed in the depth direction toward the bottom by making the reduced diameter portion the above shape. In other words, the diameter of the cross-section perpendicular to the bottom can be reduced, that is, the shape can be made concave toward the bottom side. For this reason, when pressure is applied to the ceramic blank placed at the gate by the piston, the ceramic material constituting the ceramic blank tends to flow toward the sprue line formed by connecting to the bottom of the gate, and the bottom of the gate It is possible to suppress damage such as chipping.

  An example of the shape of the truncated cone is shown in FIG. 2A as the reduced diameter portion of the wax pattern planting portion of the crucible former of the present embodiment, but it is not limited to such a form, and the end portion What is necessary is just to be comprised so that the diameter of the cross section perpendicular | vertical to a longitudinal direction may become small toward the side.

  The example of a structure of the other shape of a wax pattern planting part is shown to Fig.3 (a)-FIG.3 (d). FIGS. 3A to 3D each show a cross section in a plane passing through the central axis of the wax pattern planting portion and parallel to the central axis.

  For example, as shown in FIG. 3A, the wax pattern planting portion can have a shape provided with a hemispherical reduced diameter portion 312 on the cylindrical portion 311. Moreover, as shown in FIG.3 (b), it can also be set as the shape provided on the cylindrical shape part 321 with the hemispherical shape which made the foremost surface flat surface, ie, the reduced diameter part 322 of hemispherical trapezoid shape.

  3A and 3B, the reduced diameter portion has a hemispherical shape or a shape including a part of the hemisphere, but the sphere (hemisphere) here is limited to a true sphere. It may be an ellipsoid. That is, the reduced diameter portion can be a shape that includes a true sphere or a part of an ellipsoid. However, it is preferable that the cross section of the reduced diameter portion in a plane perpendicular to the longitudinal direction of the wax pattern planting portion is a perfect circle (perfect circle). This is because when a mold is formed using a crucible former having a wax pattern planting part including a reduced diameter part having a round cross section in a plane perpendicular to the longitudinal direction of the wax pattern planting part, it is formed on the mold. The section perpendicular to the depth direction of the gate is made into a perfect circle over the entire depth direction. That is, the gate can be made isotropic with respect to a plane perpendicular to the depth direction of the gate. For this reason, for example, when the ceramic blank has a shape corresponding to the formed gate, the ceramic blank can be easily inserted into the gate only by aligning the ends of the longitudinal direction.

  Moreover, the wax pattern planting part of the crucible former of this embodiment can also be made into the shape provided with the conical reduced diameter part 332 on the column-shaped part 331 as shown in FIG.3 (c).

  Also, in the portion where the cylindrical portion and the reduced diameter portion are in contact so far, the diameters of the surfaces perpendicular to the longitudinal direction of the wax pattern planting portions have the same form, but are not limited to such form. Absent. In the portion where the cylindrical portion and the reduced diameter portion are in contact, the diameters of the surfaces perpendicular to the longitudinal direction of the wax pattern planting portions may be different.

  For example, as shown in FIG. 3D, the diameter c of the surface perpendicular to the longitudinal direction of the wax pattern planting portion of the cylindrical portion 341 (hereinafter simply referred to as “diameter c”), and the reduced diameter portion 342 The diameter d (hereinafter simply referred to as “diameter d”) of the surface perpendicular to the longitudinal direction of the wax pattern planting portion at the end of the cylindrical portion 341 may be different.

  However, the diameter c is preferably longer than the diameter d so that the crucible former can be removed after filling the investment material.

  When the mold is formed using the crucible former having the wax pattern planting portion of the present embodiment, the mold gate is, as will be described later, a cylindrical portion formed corresponding to the columnar portion, and a compressed portion. And a reduced diameter bottom portion formed on the bottom side of the gate corresponding to the diameter portion. When a mold is molded using a wax pattern planting portion having a diameter c longer than the diameter d as shown in FIG. 3D, the diameter c is formed at the portion where the cylindrical portion and the reduced diameter bottom portion come into contact. And a flat surface having a difference width of the diameter d. For this reason, even if the shape of the ceramic blank is cylindrical as in the conventional case, the flat portion supports the ceramic blank in the gate, and when performing press molding, the ceramic blank is displaced or vibrated in the horizontal direction. It can be suppressed and is preferable.

  FIG. 3D shows an example of a hemispherical shape in which the reduced diameter portion 342 has a flat front surface in a cross section in a plane parallel to the central axis passing through the central axis of the wax pattern planting portion. However, it is not limited to such a form. As described above, the reduced diameter portion can have various shapes such as a hemispherical shape, a truncated cone shape, and a conical shape.

  In FIG. 2A and FIG. 3A to FIG. 3D, the wax pattern planting portion has a reduced diameter portion along the longitudinal direction of the wax pattern planting portion as the shape of the wax pattern planting portion. Although the example in which the diameter of the surface perpendicular to the longitudinal direction of the part continuously changes is shown, the present invention is not limited to such a form. For example, the diameter of the reduced diameter portion varies along the longitudinal direction of the wax pattern erection portion, and the diameter of the surface perpendicular to the longitudinal direction of the wax pattern erection portion changes discontinuously, specifically, for example, the center of the reduced diameter portion The reduced diameter portion may have a step shape in a cross section passing through the axis. However, in particular, as shown in FIG. 2 (a) and FIGS. 3 (a) to 3 (d), the reduced diameter portion extends in the longitudinal direction of the wax pattern planting portion along the longitudinal direction of the wax pattern planting portion. It is preferable that the diameter of the surface perpendicular to the direction is continuously changed.

  The diameter of the reduced diameter portion is configured so that the diameter of the surface perpendicular to the longitudinal direction of the wax pattern planting portion is continuously changed along the longitudinal direction of the wax pattern planting portion. The bottom of this will include an inclined surface. For this reason, when the ceramic blank is press-molded, the ceramic material is particularly easy to flow, and it is possible to more reliably suppress the chipping at the bottom of the gate.

  As described above, the crucible former 20 of the present embodiment has the reduced diameter portion 212, so that a cross section perpendicular to the depth direction is formed along the depth direction of the gate at the bottom side of the gate of the produced mold. A portion having a smaller diameter (hereinafter also referred to as a “reduced diameter bottom portion”) can be formed.

  At this time, the length of the reduced diameter bottom portion formed corresponding to the reduced diameter portion 212 in the direction parallel to the depth direction of the gate is not particularly limited, but is preferably 2 mm or more, for example, 3 mm or more. It is more preferable. This is because chipping or the like can be particularly suppressed from occurring at the bottom of the gate by setting the length of the reduced diameter bottom portion in the direction parallel to the depth direction of the gate to 2 mm or more.

  For this reason, the length a of the reduced diameter portion 212 in the direction parallel to the longitudinal direction of the wax pattern planting portion 21 is preferably 2 mm or more so that the crucible former 20 can form a sprue having such a shape. More preferably.

  However, when the ceramic blank is press-molded, the piston that presses the ceramic blank usually has a cylindrical shape, and has substantially the same diameter as the cylindrical portion 211 of the crucible former. For this reason, the piston used when press-molding the ceramic blank can only be inserted up to the cylindrical portion formed corresponding to the columnar portion 211 of the gate formed in the mold, and corresponds to the reduced diameter portion 212. Thus, it cannot be inserted into the reduced diameter bottom portion where the diameter of the gate is reduced. Therefore, when the ceramic blank is press-molded, the ceramic material constituting the ceramic blank remains on the reduced diameter bottom portion corresponding to the reduced diameter portion 212.

  For this reason, from the viewpoint of reducing the loss of the ceramic material constituting the ceramic blank, the length in the direction parallel to the depth direction of the gate is preferably 20 mm or less, and preferably 10 mm or less. More preferred.

  And the length a of the direction parallel to the longitudinal direction of the wax pattern planting part 21 of the reduced diameter part 212 is preferably 20 mm or less so that the crucible former 20 can form the gate of the shape. It is more preferable that

  Note that the length b of the cylindrical portion 211 in the direction parallel to the longitudinal direction of the wax pattern planting portion 21 is not particularly limited. For example, the size of the ceramic blank used when manufacturing a dental prosthesis Or, it can be arbitrarily selected according to the length of the piston. However, the length in a direction parallel to the longitudinal direction of the wax pattern planting portion 21 of the columnar portion 211 is arranged so that a ceramic blank having a size capable of reliably filling the gap corresponding to the dental prosthesis formed in the mold can be disposed. The length b is preferably 10 mm or more, and more preferably 20 mm or more.

  Further, if the length b of the columnar portion 211 in the direction parallel to the longitudinal direction of the wax pattern planting portion is excessively long, the amount of investment is increased, and the length of the piston when the ceramic blank is press-molded is increased. It is necessary to lengthen the length. For this reason, the length b of the columnar portion 211 in the direction parallel to the longitudinal direction of the wax pattern planting portion 21 is preferably 100 mm or less, and more preferably 70 mm or less.

  The diameter c of the cylindrical portion 211 is not particularly limited, and can be arbitrarily selected according to the size of the piston used when press-molding the ceramic blank. The diameter c of the cylindrical portion 211 can be set to, for example, 7 mm or more and 70 mm or less.

  Other configurations of the crucible former are not particularly limited. For example, as shown in FIGS. 2A and 2B, an opening 22 is formed at the tip of the wax pattern planting portion 21. can do. As shown in FIG. 2A, the opening 22 can be a through hole that penetrates to the base 23 of the crucible former 20. Moreover, it can also be set as the recessed part which is not penetrated to the base 23 of the crucible former 20. FIG.

  For example, a sprue line portion of a wax pattern can be fixed to the opening 22. Further, when the opening 22 is a through-hole penetrating to the base 23, it can also be used as a draining hole when the crucible former 20 is washed before and after use.

  Even when the opening 22 is provided, the sprue line portion may be fixed to a place other than the opening 22, for example, the side surface of the reduced diameter portion 212 or the like.

  The crucible former 20 can further be provided with a disk-shaped base 23 for fixing the wax pattern planting portion 21. As will be described later, after the ring is fixed to the crucible former 20, a casting mold can be formed by filling, curing, and firing an investment material in a region surrounded by the crucible former and the ring. For this reason, the base 23 constitutes the bottom of the mold filled with the investment material. The base 23 can have a disk shape as shown in FIGS.

  And the base 23 of the crucible former 20 can have the recessed part 231 for fixing a ring. For example, a mold for filling the investment material can be formed by engaging the ring with the recess 231. For example, as shown in FIGS. 2A and 2B, the concave portion 231 can be formed in an annular shape along the outer periphery of the base portion 23.

  The material of the crucible former is not particularly limited, and the crucible former can be formed from, for example, various resins.

  According to the crucible former of the present embodiment described above, the diameter of the surface perpendicular to the longitudinal direction of the wax pattern planting portion is small toward the end of the wax pattern planting portion. A reduced diameter portion is provided. When the mold is formed using the crucible former, a reduced-diameter bottom portion in which the diameter of the cross section perpendicular to the depth direction becomes smaller toward the bottom portion side of the gate can be formed.

For this reason, when a ceramic blank is arranged in the gate and the press molding is performed, the ceramic material is particularly easy to flow into the gap and the sprue line portion of the shape corresponding to the dental prosthesis connected to the gate, and the bottom of the gate The occurrence of chipping can be suppressed.
[Method of manufacturing dental prosthesis, ceramic blank]
Next, a method for manufacturing a dental prosthesis using the crucible former of the present embodiment and a structural example of a ceramic blank that can be suitably used for manufacturing a dental prosthesis will be described.

  The ceramic blank is sometimes called a ceramic block or a ceramic ingot.

  The method for producing a dental prosthesis can have, for example, the following steps in the order listed below.

  A wax pattern fixing step of fixing the wax pattern to the crucible former of the present embodiment.

  A burying process in which the wax pattern is buried in the investment material.

  An incineration process in which, after the investment material is cured, the investment material including the wax pattern is heated to incinerate the wax pattern to form a mold.

  A molding process in which a ceramic blank is cast into a mold.

  Here, each process of the manufacturing method of the dental prosthesis of this embodiment is demonstrated below, using FIG. 4 (a)-FIG.4 (d), FIG. 5 (a), (b).

  4 (a) to 4 (d), 5 (a), and 5 (b) schematically show the respective steps of the method for manufacturing a dental prosthesis according to the present embodiment.

  First, before starting the manufacturing method of the dental prosthesis of this embodiment, as shown in FIG. 4A, a wax pattern 411 having a shape corresponding to the dental prosthesis to be formed can be prepared. .

  The wax pattern 411 can be formed on a gypsum model 42 produced by pouring gypsum into a tooth mold acquired from a patient with an impression material or the like so that it can have a shape corresponding to the dental prosthesis to be formed.

  By casting the wax pattern 411 in the investment material and incinerating it after the investment material is cured, a mold having a void having a shape corresponding to the dental prosthesis can be formed in the investment material. Then, a dental prosthesis having a desired shape can be formed by supplying a ceramic material to the gap in the mold.

  As shown in FIG. 4 (a), when a void having a shape corresponding to the dental prosthesis is formed in the investment material, a supply path for supplying ceramics can also be formed in the void. It is preferable to form the sprue line 412 together with the pattern 411. Further, both the wax pattern 411 and the sprue wire 412 are preferably formed of dental wax.

  Next, a wax pattern fixing step can be performed as preparation for performing the burying step. In the wax pattern fixing step, the wax pattern 411 can be fixed on the crucible former 43 via the sprue wire 412 as shown in FIG. FIG. 4B shows an example in which two sets of wax patterns 411 and sprue wires 412 are fixed. However, the present invention is not limited to such a form. For example, one set, or three or more sets of wax patterns 411, In addition, the sprue wire 412 can be fixed. FIG. 4B shows an example in which a crucible former having the same shape as the crucible former 20 shown in FIG. 2 is used. A formable crucible former can be used. Since the Crucible Former has already been described, the description is omitted here.

  Then, as shown in FIG. 4C, the ring 44 surrounds the wax pattern 411 and the sprue line 412 on the periphery of the base of the crucible former 43 to which the wax pattern 411 and the sprue line 412 are fixed. Can be placed. At this time, the ring 44 is fixed by meshing with a recess provided in the crucible former 43. A liner (not shown) may be disposed and used inside the ring 44. Then, a burying step of burying the wax pattern 411 in the investment material can be performed.

  In the burying step, as shown in FIG. 4C, a slurry-like burying material 45 is poured into the ring 44, and the wax pattern 411 and the sprue wire 412 are buried.

  The investment material used in the investment process is not particularly limited, and for example, an investment material used when producing a dental prosthesis made of ceramic can be preferably used. Specifically, for example, a phosphate-based investment material can be preferably used.

  Next, after the investment material is cured, the investment material including the wax pattern 411 is heated to incinerate the wax pattern 411 to perform an incineration process for forming a mold.

  In the incineration step, the crucible former 43 can be removed and fired after the investment material has hardened. The firing temperature at this time is not particularly limited, and the temperature can be selected according to the material of the wax used to form the wax pattern 411 and the sprue wire 412 and the material of the investment material 45.

  By performing the incineration process, as shown in FIG. 4D, the wax pattern 411 is removed, and a void 461 having a shape corresponding to the dental prosthesis to be formed is formed. At this time, since the sprue wire 412 is also incinerated at the same time, a sprue wire portion 462 leading to the gap 461 is formed. Further, by performing the incineration step, the investment material is also fired to obtain a fired body 47 of the investment material, and a void 461 having a shape corresponding to the dental prosthesis formed in the fired body 47 of the investment material is formed. It can be set as the casting_mold | template 50 which has.

  In FIG. 4 (d), the ring 44 remains, but depending on the material of the ring 44, the investment material is hardened and then removed together with the crucible former 43 and subjected to an incineration process. You can also.

  At one end of the sprue wire portion 462, a gate 48 is formed for placing a ceramic blank in a molding process described later. The gate 48 has a shape corresponding to the wax pattern planting portion of the crucible former 43. And as already stated, the wax pattern planting part of the crucible former of this embodiment has a columnar part and a reduced diameter part. For this reason, the gate 48 correspondingly corresponds to the cylindrical portion disposed on the upper side and having a cylindrical shape, and along the depth direction of the gate 48, that is, from the upper side to the bottom side of the gate 48. , And a reduced diameter bottom portion in which the diameter of the cross section perpendicular to the depth direction of the gate 48 is reduced.

  Next, a molding step of casting the ceramic blank into the mold 50 formed in the incineration step can be performed. In the molding step, the ceramic blank can be filled by heating and pressurizing the void 461 in the mold 50 formed by burning the wax pattern.

  Specifically, the ceramic blank 49 is disposed in the gate 48 of the mold 50 described with reference to FIG. 4D, and the ceramic blank 49 is heated together with the mold 50 and press-molded, whereby the gap 461 and the sprue wire are formed. The portion 462 can be filled with a ceramic material.

  The shape of the ceramic blank used in the molding process is not particularly limited as long as it is a shape that can be disposed in the gate of the mold, and a ceramic blank having an arbitrary shape can be used. However, when the ceramic blank is pressed with a piston for press molding, if the ceramic blank is displaced or vibrated in a horizontal direction without being sufficiently softened, the piston may also be displaced or vibrated in the horizontal direction. When the piston is displaced or vibrated in the horizontal direction, the ceramic material may enter the gap between the piston or between the piston and the side wall of the gate. In addition, the horizontal direction here means the direction perpendicular | vertical to the pressing direction at the time of pressing a ceramic blank with a piston.

  Therefore, it is preferable that the ceramic blank has a shape corresponding to the gate including the bottom of the reduced diameter so that the ceramic blank is not easily displaced horizontally in the gate when the ceramic blank is pressed by the piston. The gate has a shape corresponding to the wax pattern planting portion of the crucible former used when producing the mold. For this reason, it is preferable that the ceramic blank has an outer shape corresponding to the wax pattern planting portion of the crucible former used when producing the mold.

  Here, the ceramic blank which can be used suitably for the casting_mold | template which has the gate formed using the crucible former of this embodiment is demonstrated.

  The ceramic blank 49 used for the mold having the gate formed using the crucible former of the present embodiment has a body portion 491 and a reduced diameter in accordance with the shape of the gate 48, for example, as shown in FIG. A ceramic blank 49 including an end 492 is preferable.

  The body 491 may have a cylindrical shape. The reduced diameter end portion 492 is provided adjacent to the body portion 491 along the longitudinal direction of the ceramic blank 49 so that the diameter of the surface perpendicular to the longitudinal direction of the ceramic blank decreases toward the end portion of the ceramic blank 49. It is preferable that it is comprised.

  Further, as described above, the diameter of the reduced diameter portion of the wax pattern planting portion of the crucible former is continuous with the diameter of the surface perpendicular to the longitudinal direction of the wax pattern planting portion along the longitudinal direction of the wax pattern planting portion. It is preferable that it is comprised so that it may change. For this reason, also in the ceramic blank 49, it is preferable that the diameter of the reduced diameter end portion 492 continuously change along the longitudinal direction of the ceramic blank 49.

  Furthermore, the length of the reduced diameter end portion 492 of the ceramic blank 49 in the direction parallel to the longitudinal direction of the ceramic blank 49 is the wax pattern planting portion of the reduced diameter portion of the crucible former used when producing the mold. It is preferable that the length is the same as the length in the direction parallel to the longitudinal direction.

  For this reason, the lower limit of the length of the reduced diameter end portion 492 of the ceramic blank 49 in the direction parallel to the longitudinal direction of the ceramic blank 49 is preferably 2 mm or more, and more preferably 3 mm or more. The upper limit value of the reduced diameter end portion 492 of the ceramic blank 49 in the direction parallel to the longitudinal direction of the ceramic blank 49 is preferably 20 mm or less, and more preferably 10 mm or less.

  The length of the body portion 491 of the ceramic blank 49 in the direction parallel to the longitudinal direction of the ceramic blank is not particularly limited. For example, a ceramic material filling the gap 461 and the sprue line portion 462 of the mold 50 can be secured. It is preferable to select. The length of the body 491 of the ceramic blank 49 in the direction parallel to the longitudinal direction of the ceramic blank 49 is preferably, for example, 5 mm or more, and more preferably 8 mm or more.

  The upper limit value of the length of the body 491 of the ceramic blank 49 in the direction parallel to the longitudinal direction of the ceramic blank 49 is not particularly limited, but may be selected so that the ceramic blank 49 can be accommodated in the gate 48. preferable. For this reason, the length of the body 491 of the ceramic blank 49 in the direction parallel to the longitudinal direction of the ceramic blank 49 is, for example, preferably 50 mm or less, and more preferably 30 mm or less.

  The diameter of the body portion 491 of the ceramic blank 49 is preferably equal to the diameter of the cylindrical portion of the gate 48. And the diameter of the cylindrical part of the gate 48 is prescribed | regulated by the column-shaped part 211 (refer Fig.2 (a)) of the wax pattern planting part 21 of a crucible former. For this reason, the diameter of the trunk | drum of ceramic blank can be 7 mm or more and 70 mm or less similarly to the column-shaped part 211 of the wax pattern planting part 21. FIG.

  The material of the ceramic blank is not particularly limited, and any material can be selected according to the dental prosthesis to be produced.

  In the molding step, as shown in FIG. 4D, after the ceramic blank is placed in the gate 48 of the mold 50, the ceramic blank is pressurized with a piston (not shown) while heating, and the sprue wire portion 462, and The gap 461 can be filled with a ceramic material. The heating temperature and pressurizing conditions during press molding are not particularly limited, and can be arbitrarily selected according to the material of the ceramic blank to be used.

  By performing the molding process described above, a ceramic molded body 51 can be produced as shown in FIG.

  After the molding process is finished, the dental prosthesis 511 can be obtained by taking out the ceramic molded body 51 from the mold and cutting it along the dotted line X as shown in FIG.

  In the method for manufacturing a dental prosthesis according to the present embodiment described above, a mold is formed using the aforementioned crucible former. For this reason, when a ceramic blank is placed in the mold gate and press-molded, it is possible to suppress the occurrence of chipping at the bottom of the gate.

20, 43 Crucible former 21 Wax pattern planting part 211, 311, 321, 331, 341 Cylindrical part 212, 312, 322, 332, 342 Reduced diameter part 50 Mold

Claims (3)

A crucible former used for the production of ceramic dental prosthesis, having a wax pattern planting part,
The wax pattern planting part is
A cylindrical portion having a cylindrical shape;
A surface that is provided adjacent to the cylindrical portion along the longitudinal direction of the wax pattern planting portion and that is perpendicular to the longitudinal direction of the wax pattern planting portion toward the end of the wax pattern planting portion. Crucible former including a reduced diameter portion having a reduced diameter.   The crucible former according to claim 1, wherein a length of the reduced diameter portion in a direction parallel to a longitudinal direction of the wax pattern planting portion is 2 mm or more and 20 mm or less.   The crucible fork according to claim 1 or 2, wherein a diameter of a surface of the reduced diameter portion that is perpendicular to a longitudinal direction of the wax pattern planting portion continuously changes along a longitudinal direction of the wax pattern planting portion. Ma.

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