JPH0716244A - Manufacture of denture - Google Patents

Abstract

PURPOSE:To reduce time for preheating models, prevent the pars alveolaris mandibulae of a denture base from developing shrink marks, provide good deburring and also good cooling after molding. CONSTITUTION:Models 13, 14 made of gypsum and formed in flasks 11, 12 are previously heated. Nearly the same heating in all is applied to both the models 13, 14 by irradiating far infrared radiation from the upper area at the surfaces of the models 13, 14 in air. In this case, the tooth socket part 13a of the lower model 13 and the tooth part 2 of the upper model 14 are covered with aluminum foil 81, 82. Thus, on the surfaces of the models 13, 14, palate parts 13b, 14b and deburred part 13c, 14c have temp. higher than that of the tooth socket part 13a and the tooth part 2. Thus, only the surface parts of the model 13, 14 dry quickly and increase in temp. Water remains in the models 13, 14 to prevented gypsum from dewatering and contraction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a denture, and more particularly to a method for compression molding a denture base with a thermoplastic resin.

[0002]

2. Description of the Related Art Conventionally, as described in, for example, Japanese Patent Application Laid-Open No. 62-236543, a model made of gypsum is formed in each of a lower flask and an upper flask, and heat such as polysulfone is heated between both models. BACKGROUND ART A denture base is formed by sandwiching and compressing a floor material made of a plastic resin. At that time, finally, the floor material is placed on the model of the lower flask and heated, but before that, it is also conventionally performed to separately preheat the model and the floor material. For example, “Dental materials and instruments Vol.7 No.6 p.930-934 (1
988) "requires floor heating made of polyether sulfone to preheat the model in order to reduce the thickness of the deburring part, etc. Heating is stated to be preferred.

Conventionally, in the preheating of the model (flask heating step), for example, the flask and the model are heated by blowing hot air inside the closed chamber. However, in the heating in the closed chamber, the moisture in the closed chamber causes the humidity in the closed chamber to reach 100%, so it takes about 2 hours to heat and dry the model. Also, the entire model will be dried. Further, since the alveolar part of the model is protruding, it is located near the heater and is likely to become hotter than other parts. The lower and upper flasks are heated by separate heating devices to heat the lower model to about 220 ° C, while the upper model is heated to about 130 ° C.

By the way, in the compression molding method, the pressure loss of the press pressure mainly occurs at the peripheral portion of the palate and the denture base. When the temperature of the palate portion and the burr cutting portion in the model is low, even if the floor material is softened to a low viscosity state before compression, or even if the press pressure is as high as 3 to 5 t, the burr cutting is performed. 0.3 to 0.5 mm
Will remain in the thickness of. As a result, the occlusal height of the manufactured denture is increased. In order to prevent this, the temperature of the palate and deburring part of the model should be sufficiently high in the flask heating process, but simply increase the heater output or lengthen the heating time. Then, the alveolar part of the model becomes even hotter.
However, when the temperature of the alveolar part becomes high, the alveolar part of the denture base is thicker than the palate part, so that sink marks and voids are likely to occur in the alveolar part of the denture base due to cooling after molding. Moreover, the lower model is heated to about 220 ° C in the flask heating process, while the upper model is heated to about 130 ° C, and there is a large temperature difference between the two models, so the heat conduction of the resin teeth is poor Becomes more uneven,
Molding defects are likely to occur.

Further, the entire model is dried, but this drying causes dehydration shrinkage in an ordinary general-purpose plaster, which deteriorates the accuracy of the denture base to be molded and causes poor compatibility. Therefore, conventionally, special plaster such as heat-resistant plaster is used,
If special gypsum is used, the cost is high and the manufacturing restrictions are large. Further, if the entire model is dried, it is difficult to properly cool the model after molding, and distortion due to uneven cooling may occur in the denture base.

[0006]

As described above, in the conventional preheating of the model, the upper and lower models are set to different temperatures, and the flask and the model are heated by blowing hot air inside the closed chamber. However, it takes time, and it is difficult to achieve both good burr cutting and prevention of sink marks in the alveolar part of the denture base.Drying the entire model compels the use of special plaster such as heat-resistant plaster. However, due to the difference in temperature between the upper and lower models, there is a problem that it is difficult to properly and evenly cool after molding.

The present invention is intended to solve such a problem, and when forming a denture base by compression molding,
The purpose of this is to improve the accuracy of the denture base by preventing burr cutting and preventing molding defects such as sink marks. Furthermore, the time required for preheating the model is shortened, and the cooling after molding is well and uniformly performed.
The purpose is to be able to use general-purpose plaster.

[0008]

According to the invention of claim 1, in order to achieve the former object, a model made of gypsum is formed in each of a pair of flasks, and at this time, artificial teeth are embedded in one of the models. A flask heating step of heating both models formed in the flask in advance to a predetermined temperature in a method for producing a denture in which a denture base is molded by sandwiching and compressing a flooring material made of a heated thermoplastic resin between the models. In this flask heating step, heating is performed by irradiation from a far infrared heater facing the model, and at this time, the artificial tooth part of one model and the alveolar part of the other model are covered with heat shields, respectively. , The surface of the model, and the internal parts are brought to desired temperatures.

Further, according to the invention of claim 2, in order to achieve the latter object as well, the flask heating step is performed in an open atmosphere.

[0010]

In the method for manufacturing a denture according to the first aspect of the invention, in the flask heating step, the model is heated by irradiation from the far-infrared heater facing the model. The artificial tooth portion of one model and the alveolar part of the other model are heated. The heat shield material covers the parts and the heat shield material to block the irradiation from the far infrared heater to suppress the temperature rise of the artificial tooth part and the alveolar part of the model. As a result, the temperatures of the artificial tooth portion and the alveolar portion of the model are made to be substantially equal to or lower than the temperatures of the palate portion and the burr cutting portion of the model. Then, the denture base is molded by sandwiching and compressing the heated thermoplastic resin floor material between the models that have undergone the flask heating step. At this time, in the flask heating step, since the temperatures of the lid portion and the burr cutting portion are increased, the resin flows well in the lid portion and the burr cutting portion, and the burr cutting portion becomes thin even when compressed at a low pressure. Further, since the temperature of the artificial tooth portion and the alveolar portion of the model is relatively low, it is possible to prevent sink marks and voids from occurring in the alveolar portion that is thicker than the palate portion in the denture base due to cooling after molding.

Further, in the method for manufacturing a denture according to the second aspect of the present invention, by performing the flask heating step in an open atmosphere, the water evaporated from the gypsum diffuses into the atmosphere and the surface of the model facing the far infrared heater. The part is heated quickly,
dry. If the flask heating process is completed when only the surface of the model is dried, the surface of the model is heated to the proper temperature for molding as described above, but dehydration shrinkage does not occur even with general-purpose plaster, and a highly accurate denture Get the floor. Also, except for the surface part of the model, the temperature is below 100 ° C, including water,
Cooling after molding is quickly and uniformly performed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 10 shows an example of the manufactured denture 1. The denture 1 is a full denture of the upper jaw, 2 is a resin tooth made of acrylic resin, and 3 is a denture base made of glass fiber reinforced polycarbonate. Further, 3a is an alveolar part of the denture base 3, and 3b is a palate part thereof.
Further, FIG. 9 shows a floor material 6 which is a molding material for the denture base 3. The floor material 6 is a U-shaped plate-shaped molded product made of reinforced polycarbonate. It should be noted that the floor material 6 is formed with a plurality of grooves 7 for cutting the floor material 6 when manufacturing the partial denture.

Reference numerals 11 and 12 in FIG. 8 denote a pair of flasks used for molding the denture base 3, and these flasks 11 and 12 are models 13 and 14 made of general-purpose plaster, respectively. The lower flask 11 has a recess 15 and a pair of positioning holes 16 at the edge of the side wall, and a through hole 17 in the bottom wall.
have. In addition, the upper flask 12 is a frame body forming the side wall.
12a and a lid 12b forming a bottom wall are detachably fixed. Then, the upper flask 12 has, at the edge portion of the side wall, a convex portion 18 that fits into the concave portion 15 of the lower flask 11 and a pair of positioning pins 19 that fit into both positioning holes 16, respectively, The bottom wall has a through hole 20.
The tip of the positioning pin 19 is tapered.
Further, on the outer surface of the bottom wall of the upper flask 12, a T-shaped ridge 21
Is provided.

Next, the structure of the apparatus used for manufacturing the denture 1 will be described. 3 and 4 show a floor material preheating device 31.
Is shown. In this floor material preheating device 31, a frame 33 is fixed on a horizontal table 32.
A sheet-shaped far-infrared heater 34 is horizontally suspended in a support 33 through a support 35. The frame 33 has a box shape, and the front surface and the lower portion are open. The heater 34 is made by embedding a heating wire in ceramics and has a length and width of 150 mm and an output of 300 W. Further, 36 is a floor material table, and the floor material table 36 is placed on the table 32 and is taken in and out of the frame 33.
The flooring base 36 is made of aluminum and is thick, and has legs 37 at the bottom to form a heat radiation shape. In addition to aluminum, a suitable metal having high thermal conductivity is used as the material of the floor base 36.

1 and 2 show a flask heating device 41. This flask heating device 41 has a housing 43 made of punching metal and having an opening 42 at the lower front surface, and a drawer that is put in and taken out through the opening 42 in the housing 43.
44 are stored. The drawer 44 is also made of punching metal, and a breathable chamber communicating with the outside air is formed in the housing 43 and the drawer 44. The drawer 44 is guided by the guide rail 45 with respect to the housing 43. Also,
A handle 47 is provided on a front plate 46 fixed to the front of the drawer 44. Further, four planar far-infrared heaters 48 are horizontally hung from the upper portion of the housing 43 via a support 49. Each of these heaters 48 has a heating wire embedded in ceramics.
And the output is 200W.

5 and 6 show the main heating device 51 and the pressing device 52. These are arranged on the same horizontal metal table 53. In the main heating device 51 arranged on one side of the rectangular table 53, a frame 54 is fixed on the table 53, and a planar far-infrared heater 55 is horizontally suspended in the frame 54. There is. The frame 54 is box-shaped, and has a front surface and a lower portion opened. Further, the heater 55 is one in which a heating wire is embedded in ceramics.
It is 00W. The output is not limited to that,
The watt density is preferably ² to 8 W / cm ² , and the total watt density is preferably 400 to 1000 W.

The pressing device 52 is provided on a side portion of the table 53 adjacent to the one side portion, and has a pair of rods 61 that are moved up and down by driving a hydraulic or pneumatic driving device (not shown). ing. The upper flask mounting plate 62 is fixed to the upper ends of the rods 61, and the lower surface of the mounting plate 62 is provided with a T of the upper flask 12.
A holder 64 forming a bag T groove 63 into which the character-shaped convex strip 21 is fitted is fixed. Further, on the table 53, stoppers (not shown) are fixed at positions inside the rods 61.

Further, a transfer arm 71 for moving the lower flask 11 from the main heating device 51 to the pressing device 52 is slidably provided on the table 53. This transfer arm 71 rotates horizontally with one end as a fulcrum 72, and has a handle 73 on the free end side. And
A pair of sandwiching pieces 74 sandwiching one side portion of the lower flask 11 is fixed to an intermediate portion on the side surface of the transfer arm 71. These sandwiching pieces
The tip of 74 is widened for guidance. Further, a protrusion 75 is fixed to the side surface of the transfer arm 71 on the free end side. On the other hand, on the table 53, press equipment
At a position near 52, a holder 76 that detachably holds the protrusion 75 is provided.

Next, a method for manufacturing a denture will be described. First, in accordance with the conventional method, a working model is made of gypsum, and a denture is created on this working model, and the resin tooth 2 is arranged on this denture. Then, the working model is first buried in the lower flask 11 with gypsum. Then, in order to secure a gap for discharging excess resin during compression molding,
A spacer is attached on the model 13 so as to surround the denture. At this time, a space of 1 to 2 mm is provided between the end edge of the prosthetic tooth and the spacer in order to form the burr cut portion. Then,
Attach the frame 12a of the upper flask 12 on the lower flask 11,
Secondary burial is performed with plaster. Then, the lid 12 is attached to the frame 12a.
After mounting b and setting the gypsum, flow it out and remove the spacer. Thus, the lower model 13 for forming the resin denture base 3 is formed on the lower flask 11, and the same model 14 is formed on the upper flask 12. Then, the resin tooth 2 is embedded in the upper model 14. After that, a silicone-based separating agent is applied to the surfaces of the models 13 and 14.

When molding the denture base 3, the floor material 6 is preheated by the floor material preheating device 31 (a floor material preheating step). In this floor material preheating step, the required number of floor materials 6 are placed on the floor material base 36 in a stacked manner, and the floor material base 36 is heated.
Insert below 34. The distance d ₁ between the heater 34 and the floor material 6 is 5 cm or less. Then, the floor material 6 is heated from one side by the heater 34. At this time, the irradiation of the heater 34 is from above and the heat of the floor material 6 is absorbed by the floor material base 36, so that the temperature of the floor material 6 at the lower portion becomes considerably lower than that at the upper portion. That is, since the heating is performed in the atmosphere, the flooring base 36 is made of aluminum having a high thermal conductivity and is thick, and the lower portion of the flooring base 36 has a heat dissipation shape. There is a considerable temperature difference with the bottom.
The temperature of the floor board 36 is about 150 ° C. Due to this temperature difference, the floor material 6 becomes soft at the upper part,
The lower part is relatively hard and does not adhere to the floor pedestal 36.

Further, the flask is heated by the flask heating device 41.
The models 13 and 14 formed on 11 and 12 are heated to a predetermined temperature in advance (flask heating step). In this flask heating step, the alveolar portion 13a of the lower model 13 formed in the lower flask 11 is previously covered with an aluminum foil 81 as a heat shield having high reflectance of far infrared rays, and the upper flask is
Two resin teeth of the upper model 14 formed on 12 are covered with an aluminum foil 82 as a heat shield. In addition to the aluminum foil, an appropriate material having a high reflectance for far infrared rays can be used as the heat shield. Then, after placing the flasks 11 and 12 in the drawer 44 of the flask heating device 41, the drawer 44 is put into the housing 43. In this state, the planar heater 48 faces the exposed surfaces (surfaces) of the models 13 and 14 of the flasks 11 and 12 from above. The distance d between the heater 48 and the surfaces of the models 13 and 14
₂ , d ₃ is 5 cm or less. In this way, the models 13 and 14 are heated by the irradiation of far infrared rays from the heater 48, but in the heating by far infrared rays, the water contained in the plaster of the models 13 and 14 moves from top to bottom, Only the surface of 13 and 14 rises in temperature greatly and dries. It should be noted that part of the water in the gypsum becomes steam and flows out from the through holes 17 and 20 in the bottom bottoms of the flasks 11 and 12. And since the heating is done in the atmosphere communicating with the outside air, it takes about 30 to 60 minutes
Only the surface parts of 13 and 14 are sufficiently dried, and at this time, the model 1
The parts below the surface of 3 and 14 still contain water, and the temperature is kept below 100 ° C. Also, the lower model 13
The alveolar part 13a of the above and the two resin teeth of the upper model 14 are covered with aluminum foils 81 and 82.
Since the irradiation from the far-infrared heater 48 is blocked by 81 and 82, the temperatures of the alveolar part 13a and the two resin teeth are
The palate portions 13b and 14b of the models 13 and 14 and the deburring portion 13c,
It will be slightly lower than the temperature of 14c. In particular, in the lower model 13, the alveolar part 13a is located closer to the heater 48 than the palate part 13b and the burr cutting part 13c, but the temperature is surely controlled by the covering of the aluminum foil 81 as described above. On the surfaces of the models 13 and 14, the temperature of the alveolar part 13a is 100 to 20.
0 ℃, the temperature of the palate 13b, 14b is 160-250 ℃, the temperature of the deburring part is 160-250 ℃, the temperature of two resin teeth is 80-
Around 120 ° C is appropriate.

Then, after the lower flask 11 which has undergone this flask heating step is taken out from the drawer 44 and the aluminum foil 81 is removed, as shown in FIG. 7, the alveolar portion 13a of the lower model 13 is removed.
The floor material 6 that has undergone the floor material preheating step is placed on top. That is, in the floor material preheating device 41, the floor material base 36 is pulled out, and if necessary, the floor material 6 on the floor material base 36 is first shaped into the shape of the alveolar portion 3a by tweezers or the like. Next, the floor material 6 is picked up with tweezers and carried, and the alveolar part of the lower model 13
Place on top of 13a. At this time, the floor material 6 is turned upside down, and the softened surface 6a of the floor material 6 is pressed against the alveolar portion 13a of the lower model 13 to be positioned. Then, the lower flask 11 is attached to the main heating device 51. At this time, as shown in FIG. 5, the transfer arm 71 is turned toward the main heating device 51, and the rear part of the lower flask 11 placed on the table 53 is clamped by both holding pieces of the transfer arm 71.
Insert between 74. In this state, the far infrared heater 55 faces the floor material 6 of the lower model 13 from above and heats it (main heating step). As a result, the relatively soft surface is softened by the preliminary softening of the floor material 6. The distance d ₄ between the heater 55 and the lower model 13 is preferably about 1-5 cm. Also, the heating time is 40
~ 120 seconds is good. At this time, since the heating is performed in the atmosphere and the irradiation from the heater 55 is from above, the lower portion of the lower flask 11 is naturally cooled. As a result, the floor material 6 on the lower model 13 has a higher temperature at the upper portion than at the lower portion, and the viscosity of the upper portion of the floor material 6 is such that it is heat-sealed to the resin teeth 2, The lower part of 6 has a higher viscosity.

At the time when the flooring material 6 has been appropriately softened in the main heating step, the upper flask 12 that has undergone the flask heating step is taken out from the drawer 44 of the flask heating device 41, the aluminum foil 82 is removed, and then the upper flask 12 is moved up and down. It is inverted and attached to the upper flask attachment plate 62 of the press device 52. That is, the T-shaped ridge 21 of the upper flask 12 is inserted into the bag T groove 63 until it stops. Along with this, as shown in FIG.
Grasp and rotate the transfer arm 71 toward the pressing device 52. The transfer arm 71 rotates until the protrusion 75 is engaged with the holder 76, but the lower flask 11 hits a stopper on the table 53 and stops, and is positioned at a predetermined position on the table 53. Then, as shown in FIG. 5, the upper flask attachment plate 62 is lowered together with the rod 61, and the flasks 11 and 12 are closed and pressurized. After that, the transport arm 71 is rotated in the opposite direction and returned to the main heating device 51, as shown by a chain line in FIG. When the mold is closed, the positioning pin 19 and the convex portion 18 of the upper flask 12 are fitted into the positioning hole 16 and the concave portion 15 of the lower flask 11, respectively, so that both flasks 11 and 12 are finally positioned with respect to each other. Thus, as shown in FIG. 8, the denture base 3 is formed by compressing the floor material 6 between the models 13 and 14.
At this time, the pressure applied to the flasks 11 and 12 is the models 13 and 14
It is preferably about 10 to 45 kg / cm ^{2 with} respect to the surface area of, and low pressure may be used. Therefore, as the press device 52 used,
A low pressure 800 kg to 1.5 ton press is sufficient. As described above, the floor material 6 heated by the main heating device 51 is softer in the upper portion than in the lower portion, so that the upper portion mainly flows and is filled between the models 13 and 14. When the mold is closed, the surplus resin is pushed out to the outside through the burr cutting portions 13c and 14c between the models 13 and 14 and becomes the overflow portion 3c. Further, at the time of compression molding, the resin tooth 2 is heat-sealed to the floor material 6, that is, the denture base 3, so that both are securely fixed.

After this pressurization is continued for 60 to 90 seconds, the pressurization is released and the flasks 11 and 12 which are still closed are removed from the press device 52. Then, these flasks 11 and 12 are clamped, put into water, and cooled. After cooling sufficiently, the flasks 11 and 12 are opened, the models 13 and 14 are crushed, and the denture 1 is taken out. Further, in the burr cutting portion 3d, the overflow portion 3c is cut by scissors and polished, and the denture 1 as shown in FIG.
Is completed.

As described above, by heating the floor material 6 in advance, the floor material 6 can be reliably positioned on the alveolar portion 13a of the lower model 13. In addition, in the floor material preheating step, as described above, the floor material 6 placed on the floor material base 36 is heated from above in the atmosphere, whereby the floor material 6 on the floor material base 36 is heated.
Since the upper part becomes softer while the lower part remains relatively hard, it is easy to handle when transferring the floor material 6 from the floor material base 36 to the lower model 13 using tweezers. That is, the floor material 6 does not cling to the floor material base 36, the floor material 6 does not excessively deform, and the tweezers facilitate handling. Nevertheless, the floor material 6 is turned upside down and its softened surface 6a is the lower model.
The alveolar part 13a of 13 is pressed to contact the alveolar part 13a.
The floor material 6 can be easily and surely positioned in the shaping position with respect to a.

Also, in the flask heating step, by heating only in the upper part in an open atmosphere, water evaporated from the models 13 and 14 made of gypsum is pushed downward,
Only the surface of 13 and 14 can be dried quickly. That is, it can be dried as needed in 30 to 60 minutes. Also, a model
By drying only the surface of 13 and 14 and leaving the inside of the models 13 and 14 containing water, even if general-purpose plaster is used, there is no dehydration shrinkage and the strength and accuracy of the models 13 and 14 do not deteriorate. . Therefore, it is possible to provide the denture 1 with high accuracy and good adaptability. Further, since it is not necessary to use special gypsum such as heat-resistant gypsum, it is possible to cope with changes during manufacturing. Further, when cooling after compression molding, since the entire inside of the models 13 and 14 except for the surface portion contains water, cooling is performed at the same time as the pressing, and the entire denture base 3 is quickly and uniformly cooled, It is possible to provide the denture 1 with good compatibility and little distortion. Also, the alveolar part of the models 13 and 14
13a and 2 parts of the resin tooth are covered with aluminum foils 81 and 82 to control the temperature to suppress the temperature of the alveolar part 13a and the 2 parts of the resin tooth, and the palate parts 13b, 14b and the deburring part 13 are also provided.
Since the temperatures of c and 14c are increased, these palate portions 13b and 14c are
The resin flows well in b and the burr cutting parts 13c and 14c,
Even with compression molding at low pressure, it is possible to obtain a burr cutting portion 3d that is thin and easy to cut with a thickness of 0.1 mm or less, and it is possible to reduce push-out error.
Along with this, by lowering the temperature of the alveolar part 13a and the resin tooth 2 part and heating both the upper and lower models 13 and 14 to the same extent as a whole, the cooling after molding can be made good and uniform, and It is possible to prevent sink marks and voids from occurring in the alveolar portion 3a thicker than the portion 3b. Further, the proper temperature control as described above may be performed only by setting the distance of the heater 48 and the heating time.

Further, in the main heating step, the floor material 6 is heated from above in the atmosphere, and at this time, the lower part of the lower flask 11 is allowed to cool naturally so that the temperature of the upper part of the floor material 6 is higher than that of the lower part. Therefore, during the subsequent compression molding, the resin can be surely filled up to the details between both models 13 and 14 due to the good flow of the upper part of the floor material 6, while the temperature control in the flask heating step is combined with the alveolar part 3a. It is possible to more reliably prevent sink marks and voids. In addition, for good flow of the upper portion of the floor material 6, the palate portion 3b and the deburring portion 3d can be thinned together with the temperature control in the flask heating step. The thickness of the palate 3b can be 1.0 mm or less. Moreover, since the floor material 6 is first placed only on the alveolar portion 13a, the pressure loss in the palate portion 3b during compression molding can be reduced, and the thin palate portion 3b and the burr cut portion 3d can be formed more reliably. Further, by heating the resin tooth 2 parts in the flask heating step and by sufficiently heating the upper portion of the floor material 6 in the main heating step, the upper portion of the floor material 6 made of polycarbonate and the resin tooth 2 made of acrylic resin are melted by heat. The resin teeth 2 can be easily and surely fixed to the denture base 3 by wearing them.

Further, in addition to the material of the floor material 6 being polycarbonate, the pressure required for compression molding can be lowered by preheating the models 13 and 14 described above. Therefore, as described above, general plaster is used. Does not cause any problems,
Thus, it is possible to obtain the denture 1 having less internal stress, no distortion, and good compatibility. At the same time, the manufacturing apparatus can be made small and inexpensive.

As described above, in the present embodiment, the denture 1 having excellent accuracy can be obtained, the manufacturing time can be shortened, and the operability is not bad.

In the above embodiment, the manufacture of the full denture of the upper jaw was described as an example, but it goes without saying that it is also possible to manufacture the denture of the lower jaw or the partial denture. In addition, although the U-shaped plate-like flooring material 6 is used in the above-mentioned embodiment,
The floor material is not limited to this, and a floor material having an appropriate shape such as a pellet shape or a rod shape may be used. In addition, although polycarbonate is used as the material of the flooring 6 in the above-mentioned embodiment, other suitable thermoplastic resin such as polysulfone or polyether sulfone may be used. Furthermore, the teeth are not limited to resin resin teeth made of acrylic resin, but may be ceramic teeth.

[0031]

According to the invention of claim 1, during the flask heating step of preheating both models formed in the flask, heating is performed by irradiation from a far infrared heater facing the models, and at this time, one of the models is heated. Since the artificial tooth of the model and the alveolar part of the other model are covered with heat shields respectively, the temperature of the artificial tooth and alveolar part of the model is suppressed while the temperature of the palate and deburring part of the model is sufficiently high. Yes, and by heating both models to about the same level as a whole, during subsequent compression molding, the resin flows well in the palate and deburring part, and the deburring part can be thinned even at low pressure compression. Burrs can be satisfactorily cut, and on the other hand, in the alveolar part which is thicker than the palate part in the denture base, good uniform cooling can prevent sink marks and voids from being generated due to cooling after molding.
From these, the accuracy of the manufactured denture can be improved.

Further, according to the invention of claim 2, since the flask heating step is carried out in an open atmosphere, the heating is performed by irradiation from a far infrared heater facing the model, so that only the surface portion of the model is swiftly heated. The temperature is drastically increased and the flask is dried, and the time for heating the flask can be shortened. And, by leaving water except the surface part of the model, dehydration shrinkage does not occur even with general-purpose plaster, a highly accurate denture base can be obtained, and special plaster such as heat-resistant plaster is not used. Since it is good, the restrictions on manufacturing can be reduced, and further, when cooling after molding, the entire denture base is quickly and uniformly cooled, and the accuracy of the denture base can be further improved.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention and is an explanatory cross-sectional view of heating a flask.

FIG. 2 is a perspective view of the flask heating device.

FIG. 3 is a perspective view of the same floor material preheating device.

FIG. 4 is an explanatory front view of preheating of the above flooring material.

FIG. 5 is a perspective view of the same main heating device and pressing device as above.

FIG. 6 is a perspective view of the same heating device and pressing device as above.
The state at the time of conveyance of a lower flask is shown.

FIG. 7 is an explanatory sectional view of the same main heating as above.

FIG. 8 is an explanatory sectional view of the compression molding of the above.

FIG. 9 is a perspective view of a flooring material used in the same molding.

FIG. 10 is a perspective view of the completed denture.

[Explanation of symbols]

 1 Denture 2 Resin tooth (tooth) 3 Denture base 6 Floor material 11 Lower flask (flask) 12 Upper flask (flask) 13 Lower model (other model) 13a Alveolar part 14 Upper model (one model) 48 Far infrared heater 81 Aluminum foil (heat shield) 82 Aluminum foil (heat shield)

Claims (2)

[Claims] 1. A model made of gypsum is formed on each of a pair of flasks, artificial teeth are embedded in one model at this time, and a floor material made of a heated thermoplastic resin is sandwiched between both models and compressed, In the method for producing a denture for molding a denture base, a flask heating step of heating both models formed in the flask to a predetermined temperature in advance is provided, and in this flask heating step, heating is performed by irradiation from a far infrared heater facing the model. The artificial tooth part of one model and the alveolar part of the other model at this time are respectively covered with a heat shield, so that the surface of the model and the internal parts of the denture are each characterized by a desired temperature. Production method. 2. The method for producing a denture according to claim 1, wherein the flask heating step is performed in an open atmosphere.