JP2007215708A - Master cast for indirect method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce a master cast for an indirect method which achieves a production cost reduction by simplifying its structure and allows a control of the drawing force of a dowel pin in an ideal condition by repeated insertion and drawing out of the dowel pin. <P>SOLUTION: The master cast for an indirect method comprises a tooth form model 2, the dowel pin 3 having one end fixed to the tooth form model 2 and tapered to become thinner toward its distal end, and a plaster foundation 1 having a connection hole 4 into and from which the dowel pin 3 is inserted and drawn out. The tooth form model 2 is connected detachably to the plaster foundation via the dowel pin 3 inserted into the connection hole 4. An elastic ring 5 which expands and contracts by inserting the dowel pin 3 is embedded within and is fixed to the plaster foundation 1 of the master cast. The elastic ring 5 is fixed to a position corresponding to the middle of the dowel pin 3 inserted into the connection hole 4 and presses the surface of the dowel pin 3 inserted into the connection hole 4 with its inner surface elastically. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an indirect method working model used when producing a dental prosthesis or the like.

The indirect method working model is used to manufacture various crown prostheses as follows.
(1) Before taking an impression from a patient, a dentist cuts a tooth of a portion where a crown prosthesis is provided in advance to form an abutment tooth. Therefore, the tooth model of the indirect method working model has an abutment tooth model formed in a portion where the crown prosthesis is manufactured.
(2) The lower surface of this tooth model is cut flat to make a hole, air is injected into the hole, and pressurized water is injected to clean it.
(3) Fasten the dowel pin to the hole of the tooth model using instant adhesive and instant resin.
(4) Apply a release agent to the lower surface of the tooth model and the surface of the dowel pin, and push it into a silicone rubber mold for gypsum base that has been filled with gypsum mud in advance to cure the gypsum paste to make a gypsum base.
(5) Remove the gypsum base from the silicone rubber mold to make an indirect method working model for dental technicians.
(6) Using the above indirect method working model, create a prosthetic crown to be attached to the abutment tooth model with resin or metal. At this time, the tooth models on both sides of the abutment tooth model get in the way, so a split model is made to prevent the tooth models on both sides from getting in the way. The divided model is configured such that a part for producing a crown prosthesis can be separated from an adjacent part.
(7) The division model is manufactured by cutting the tooth profile model of the indirect method work model at a predetermined position. The tooth model is cut on both sides of the part where the crown prosthesis is to be made. This divided model is detachably mounted on a gypsum base via a dowel pin.
(8) Using the divided model manufactured in this state, the crown prosthesis to be attached to the abutment tooth model is made of resin or metal. The split model that can divide the abutment tooth model from the gypsum base can be processed efficiently and accurately even at the boundary with the adjacent tooth model, so that a prosthetic crown can be manufactured efficiently. At this time, the dowel pin is inserted and removed, and the divided model is detached from the gypsum base.

  In the above-described indirect method working model, when the crown prosthesis is manufactured, the dowel pin is repeatedly inserted and removed from the connecting hole of the gypsum base when the divided model is detached from the gypsum base. When the dowel pin is repeatedly inserted and removed, the plaster peels from the inner surface of the connecting hole, and the connecting hole becomes larger. For this reason, the dowel pin can be easily pulled out, and the tooth model cut through the dowel pin cannot be connected to an accurate position of the gypsum base. When the divided model is displaced, the relative position with the adjacent tooth model is shifted. For this reason, the precision of the prosthetic prosthesis to be manufactured decreases. In addition, in the indirect method working model of the upper jaw, there is a problem that the divided model for manufacturing the crown prosthesis falls by its own weight from the gypsum base.

  In order to eliminate this drawback, a working model has been developed in which a dowel pin is inserted into a holding cylinder and the holding cylinder is fixed to a gypsum base. (See Patent Document 1)

  In the working model of Patent Document 1, a holding cylinder is embedded in a gypsum base and a connection hole is provided. The holding cylinder is not peeled off from the inner surface of the connecting hole like a plaster by inserting and removing the dowel pin. For this reason, it is possible to prevent the connecting hole from being enlarged by repeatedly inserting and removing the dowel pins.

  However, the working model of this structure has a drawback that the manufacturing cost of the holding cylinder becomes high. This is because the accuracy of the inner shape of the holding cylinder specifies the pulling force of the dowel pin. If the inner shape is slightly large, the dowel pin will fall off, and conversely if the inner shape is slightly small, the dowel pin cannot be inserted smoothly. is there. For this reason, it is necessary to manufacture the holding cylinder with extremely high accuracy, which increases the manufacturing cost.

  In addition, there is a work model that allows the tooth model to be easily separated from the gypsum base using the connection hole as a through hole, and that the bottom of the connection hole is free from clogging with foreign objects, making it easy to attach and remove the tooth model via the dowel pin. Has been developed. (See Patent Document 2)

In Patent Document 2, as shown in FIG. 1, a spacer 35 is connected to the lower end of the dowel pin 33, and the gypsum base 31 is formed so that the spacer 35 is located on the lower surface of the gypsum base 31. The spacer 35 is positioned on the same plane as the bottom surface of the gypsum base 31 with the lower surface as a flat surface. The spacer 35 is extracted from the hardened gypsum base 31. In this case, since the spacer 35 is made of an elastic material such as silicon rubber, it can be easily removed from the gypsum base 31 only by pulling. By removing the spacer 35, a recess 36 is formed on the lower surface of the gypsum base 31, and the lower end portion of the dowel pin 33 is projected into the recess 36. In this state, the lower end of the dowel pin 33 is pushed so that the tooth model 32 can be easily separated from the gypsum base 31. Further, since the lower end of the connecting hole 34 is opened by the recess 36, foreign matters are clogged at the bottom of the connecting hole 34, and the adverse effect that the dowel pin 33 cannot be inserted to the fixed position is prevented.
Japanese Utility Model Publication No. 6-46710 Japanese Utility Model Publication No. 6-15612

  However, in the structures described in Patent Documents 1 and 2, the dowel pin cannot be repeatedly inserted and removed with an ideal pulling force while having a simple structure. The working model of Patent Document 1 produces a holding cylinder embedded in the gypsum base with extremely high accuracy, so that the manufacturing cost becomes high. In the working model of Patent Document 2, after the gypsum is cured, the spacer is removed from the gypsum base. Therefore, if the dowel pin is repeatedly inserted and removed, the inner shape of the connecting hole becomes larger, and the clearance becomes larger.

  The present invention has been developed for the purpose of solving the conventional drawbacks. An important object of the present invention is to provide an indirect method working model capable of controlling the pulling force of the dowel pin to an ideal state by reducing the manufacturing cost, and repeatedly removing and inserting the dowel pin, while having an extremely simple structure. It is in.

The indirect method working model of the present invention has the following configuration in order to achieve the aforementioned object.
The indirect method working model is provided with a tooth model 2, a tapered dowel pin 3 which is fixed at one end to the tooth model 2 and becomes narrower toward the tip, and a connecting hole 4 through which the dowel pin 3 can be inserted and removed. And a gypsum base 1 connected so that the tooth model 2 can be attached and detached via a dowel pin 3 inserted into the connection hole 4. In the indirect method work model, an elastic ring 5 having elasticity that is expanded and contracted by inserting a dowel pin 3 is embedded in and fixed to a gypsum base 1. This elastic ring 5 is fixed at a position where it is inserted in the middle of the tapered dowel pin 3 inserted into the connecting hole 4, and elastically presses the inner surface against the surface of the dowel pin 3 inserted into the connecting hole 4. Yes.

  In the indirect method working model of the present invention, the elastic ring 5 can be embedded in the gypsum base 1 2 mm away from the bottom surface of the gypsum base 1. In the indirect method working model of the present invention, the elastic ring 5 can be embedded in the gypsum base 1 at a distance of 2 mm or more from the upper surface of the gypsum base 1. In the indirect method working model of the present invention, the material of the elastic ring 5 can be soft plastic, natural or synthetic rubber. Furthermore, in the indirect method working model of the present invention, the length of the elastic ring 5 can be 1 mm or more and 5 mm or less.

  The indirect method working model of the present invention can control the dowel pin pulling force to an ideal state by repeatedly inserting and removing the dowel pin while remarkably reducing the manufacturing cost with a very simple structure. In the indirect method working model of the present invention, an elastic elastic ring that is expanded and contracted by inserting a dowel pin is embedded in the gypsum base, and the dowel pin inserted into the connecting hole is inserted into the elastic ring. This is because the inner surface of the elastic ring is elastically pressed against the surface of the dowel pin. This structure can control the pressing force that presses the inner surface of the elastic ring against the surface of the dowel pin at a depth at which the tapered dowel pin is inserted into the elastic ring. By inserting the dowel pin deeply into the elastic ring, the elastic ring can be strongly pressed against the surface of the dowel pin. Since the pulling force of the dowel pin is proportional to the product of the pressing force and the friction coefficient between the dowel pin and the elastic ring, the pulling force can be increased by inserting the elastic ring deeply into the dowel pin. On the contrary, the pulling force can be weakened by inserting the dowel pin shallowly into the elastic ring. Therefore, the pulling force of the dowel pin can be controlled to the optimum value by the insertion depth of the dowel pin. Insert the dowel pin into the elastic ring so that the pulling force of the dowel pin becomes the optimum value, and if the dowel pin in this state is embedded in gypsum paste to produce a gypsum base, the dowel pin is the optimal elastic ring embedded in the gypsum base The pulling force is maintained. Therefore, the working model of the indirect method of the present invention does not require high accuracy for the elastic ring and the dowel pin, and the elastic ring can be manufactured at a very low cost because a flexible tube is cut to a predetermined length. Therefore, the present invention can be made at a lower cost than the holding cylinder into which the dowel pins are inserted. Since the elastic ring is inserted into the dowel pin and the dowel pin is embedded in the gypsum paste, the elastic ring can be easily embedded.

  Furthermore, the indirect method working model of the present invention does not change the pulling force of the dowel pin even if the dowel pin is repeatedly inserted and removed many times, and the dowel pin can always be connected to the gypsum base with an ideal pulling force. This is because the inner surface of the elastic ring does not wear like gypsum even if the dowel pin is repeatedly pulled out.

  Embodiments of the present invention will be described below with reference to the drawings. However, the example shown below illustrates the indirect method working model for embodying the technical idea of the present invention, and the present invention does not specify the indirect method working model as follows.

  Further, in this specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the examples are indicated in the “claims” and “means for solving problems” sections. It is added to the members. However, the members shown in the claims are not limited to the members in the embodiments.

  The indirect method working model shown in FIG. 2 is provided with a tooth model 2, a dowel pin 3 that fixes one end of the tooth model 2, and a connecting hole 4 through which the dowel pin 3 can be inserted and removed. A gypsum base 1 connected so that the tooth model 2 can be attached and detached via a dowel pin 3 and an elastic ring 5 fixed to the gypsum base 1 are provided.

  The tooth model 2 is manufactured from a patient's tooth profile, and is a plaster model having the same shape as the patient's tooth profile. Prior to the preparation of the patient's tooth model 2, the tooth of the portion where the patient's crown prosthesis is provided is previously abraded to form an abutment tooth. Therefore, in the tooth profile model 2 of the indirect method working model, the abutment tooth model 8 is formed in the portion where the crown prosthesis is manufactured.

  The dowel pin 3 connects the tooth model 2 to the gypsum base 1. The dowel pin 3 is inserted into a fixing hole 6 provided in the tooth model 2 and bonded and fixed to the tooth model 2. The tooth profile model 2 has a plurality of dowel pins 3 fixed thereto. The plurality of dowel pins 3 connect the divided model 7 and the tooth model 2 obtained by dividing the divided model 7 to the gypsum base 1. The divided model 7 is connected to the gypsum base 1 so as to be detachable via the dowel pin 3. The plurality of dowel pins 3 are fixed in parallel to the tooth model 2. Each dowel pin 3 is fixed to the tooth model 2 in a posture orthogonal to the upper surface of the gypsum base 1 in the figure.

  The dowel pin 3 is a metal rod having a tapered shape that can be smoothly inserted into the connecting hole 4 provided in the gypsum base 1 and can be inserted into the elastic ring 5 with a predetermined pulling force. The dowel pin 3 has a non-circular cross-sectional shape so as not to rotate into the connecting hole 4 of the gypsum base 1. The dowel pin 3 can connect the divided model 7 to the gypsum base 1 in a specific posture.

  The dowel pin 3 is inserted into the connecting hole 4 of the gypsum base 1, and the tooth model 2 is connected to the gypsum base 1 through the dowel pin 3. In particular, the divided model 7 is connected to the gypsum base 1 via the dowel pin 3 so as to be detachable. When the divided model 7 is separated from the gypsum base 1, the dowel pin 3 is pulled out from the connecting hole 4 of the gypsum base 1.

  The gypsum base 1 is provided with a connecting hole 4 into which the dowel pin 3 can be inserted and removed. Since the connecting hole 4 is for inserting the dowel pin 3 to connect the tooth model 2 to the gypsum base 1, the connecting hole 4 is provided at a position where the dowel pin 3 is inserted. The connecting hole 4 is provided in the gypsum base 1 by fixing the dowel pin 3 to the tooth model 2 and burying the dowel pin 3 in gypsum paste. Therefore, the inner shape of the connecting hole 4 is equal to the outer shape of the tapered dowel pin 3, and is formed into a tapered shape that increases toward the opening.

  Further, the gypsum base 1 has an elastic ring 5 embedded at a position where the dowel pin 3 inserted into the connecting hole 4 is inserted. The elastic ring 5 elastically presses the inner surface against the surface of the inserted dowel pin 3 to control the pulling force of the dowel pin 3 to an optimum value. The elastic ring 5 is embedded at a position where it is inserted in the middle of the tapered dowel pin 3 inserted into the connecting hole 4. The elastic ring 5 is an elastic ring that is expanded and contracted by inserting the dowel pin 3.

  The elastic ring 5 is made of either soft plastic or natural or synthetic rubber so that the tapered dowel pin 3 is inserted and elastically adhered to the surface of the dowel pin 3. The material of the elastic ring 5 is suitably a soft plastic that is a soft vinyl chloride resin. However, the elastic ring 5 can also use any soft plastic that can be elastically deformed by inserting a dowel pin, such as soft urethane resin or silicon rubber.

  The thickness of the elastic ring 5 is, for example, thicker than 0.3 mm, and preferably thicker than 0.5 mm. The thickness of the elastic ring 5 is, for example, thinner than 2 mm, preferably thinner than 1 mm. If the elastic ring 5 is too thin, the pulling force of the dowel pin 3 is too weak. On the other hand, if the elastic ring 5 is too thick, it becomes difficult to control the pulling force of the dowel pin 3. Therefore, the elastic ring 5 has an optimum thickness within the above range.

  The elastic ring 5 is preferably in the gypsum base 1 and is embedded and fixed so as not to be exposed on the surface. The elastic ring 5 is embedded and fixed at a position 2 mm or more inward from the bottom surface of the gypsum base 1 and 2 mm or more inward from the top surface of the gypsum base 1. The optimum position for embedding and fixing the elastic ring 5 is a position away from the upper surface of the gypsum base 1 by 5 to 10 mm. The elastic ring 5 that is fixed to the inside of the gypsum base 1 away from the upper and lower surfaces can reliably prevent the gypsum base 1 from falling off. However, with the elastic ring 5 inserted into the dowel pin 3, the elastic ring 5 is embedded in the gypsum base 1 so that the pulling force of the dowel pin 3 becomes an optimum value and is exposed to the surface of the gypsum base 1. There is also. In this case, the total length of the elastic ring 5 can be set to, for example, 2 mm or more, preferably 3 mm or more so as not to drop off the gypsum base 1. The elastic ring 5 embedded so as not to be exposed on the surface of the gypsum base 1 has an axial length of 1 mm or more. If the elastic ring 5 is too long, the pulling force of the dowel pin 3 is too strong. Therefore, the length of the elastic ring 5 is preferably shorter than 5 mm. However, when a flexible material having a small frictional resistance is used for the elastic ring 5, the length can be longer than 5 mm.

  When the elastic ring 5 is a soft vinyl chloride tube, the optimum wall thickness is 0.6 mm and the length is 1.5 mm.

The indirect method work model described above is manufactured by the following method, and a crown prosthesis is manufactured by the following method using the manufactured indirect method work model.
(1) The tooth profile model 2 in which the abutment tooth model 8 is formed in the portion where the crown prosthesis is manufactured is manufactured.
(2) The lower surface of the tooth model 2 is processed to be flat, and the fixing hole 6 is drilled vertically from the lower surface. The dowel pins 3 are inserted into the fixing holes 6 and bonded and fixed. In other words, the dowel pin 3 is fixed at a position where the divided model 7 is connected to the plaster base 1 via the dowel pin 3 so that the divided model 7 can be attached to and detached from the plaster base 1.
(3) Insert the elastic ring 5 into the dowel pin 3. At this time, the dowel pin 3 is inserted into the elastic ring 5 until the pulling force for pulling out the dowel pin 3 from the elastic ring 5 reaches an optimum value. When the dowel pin 3 is inserted deeply into the elastic ring 5, the elastic ring 5 is elastically greatly expanded and strongly presses the surface of the dowel pin 3. Accordingly, the pulling force of the dowel pin 3 is increased. On the contrary, when the dowel pin 3 is inserted into the elastic ring 5 shallowly, the elastic ring 5 is slightly expanded and the surface of the dowel pin 3 is weakly pressed. For this reason, the pulling force of the dowel pin 3 is weakened. Therefore, the pulling force of the dowel pin 3 can be controlled to an optimum value by the depth at which the dowel pin 3 is inserted into the elastic ring 5. Regardless of the thickness of the dowel pin 3 or the accuracy of the inner shape of the elastic ring 5, the pulling force can be adjusted to the optimum value by the insertion depth of the dowel pin 3.
(4) Apply a release agent to the lower surface of the tooth model 2 and the surface of the dowel pin 3, and push the dowel pin 3 into the gypsum paste filled in the silicone rubber mold for the gypsum base 1 to harden the gypsum paste and To do. At this time, since the elastic ring 5 is inserted into the dowel pin 3 at a predetermined position, the gypsum paste is hardened, and the elastic ring 5 is embedded and fixed to the gypsum base 1 at a predetermined position. Since the elastic ring 5 is inserted into the dowel pin 3 and embedded and fixed in the gypsum base 1, when the dowel pin 3 is inserted into the connecting hole 4, the elastic ring 5 is inserted in the middle thereof.
(5) An indirect method working model for dental technicians is produced in which the gypsum base 1 is removed from the silicone rubber mold and the tooth model 2 is connected to the gypsum base 1 via the dowel pins 3.

(6) Using the above-described indirect method work model, a crown prosthesis to be attached to the abutment tooth model 8 is made of resin or metal.
At this time, since the tooth models 9 on both sides of the abutment tooth model 8 are in the way, the crown prosthesis 10 is manufactured as shown in FIG. 3 in order to prevent the tooth models 9 on both sides from getting in the way. The tooth profile model 2 is cut on both sides of the abutment tooth model 8 so that the portion to be separated can be separated from the adjacent portion. The divided model 7 is connected to the gypsum base 1 via the dowel pin 3 so as to be detachable.
(7) The split model 7 is detached from the gypsum base 1, and the dental prosthesis 10 to be mounted on the abutment tooth model 8 is made of resin or metal.

Since the dowel pin 3 fixed to the divided model 7 is also inserted into the elastic ring 5 in a state of being inserted into the connecting hole 4, the pulling force is controlled to an optimum value by the elastic ring 5. The elastic ring 5 fixed to the gypsum base 1 does not wear like gypsum even if the dowel pin 3 is inserted and removed. For this reason, even if the divided model 7 is repeatedly attached to and detached from the gypsum base 1 and the dowel pins 3 are inserted into and removed from the connecting holes 4, the dowel pins 3 are always connected to the gypsum base 1 with an ideal pulling force. For this reason, the divided model 7 is always connected to the gypsum base 1 with an ideal pulling force.
Moreover, since the division | segmentation model 7 can be isolate | separated from the gypsum base 1, even if there exists the tooth model 9 adjacent to the abutment tooth model 8, the dental prosthesis 10 can be processed efficiently and correctly. For this reason, the accurate crown prosthesis 10 can be manufactured efficiently.

It is a partial cross section front view which shows the conventional indirect method working model. It is a section front view showing the indirect method working model concerning one example of the present invention. It is a cross-sectional front view which shows the state which took out the division | segmentation model of the indirect method work model shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Gypsum base 2 ... Tooth shape model 3 ... Dowel pin 4 ... Connection hole 5 ... Elastic ring 6 ... Fixed hole 7 ... Split model 8 ... Abutment tooth model 9 ... Tooth model 10 ... Crown prosthesis 31 ... Gypsum base 32 ... Tooth shape Model 33 ... Dowel pin 34 ... Connection hole 35 ... Spacer 36 ... Recess

Claims (5)

Tooth model (2), tapered dowel pin (3) with one end fixed to this tooth model (2) and narrowing toward the tip, and connecting hole (4) through which this dowel pin (3) can be inserted and removed An indirect method working model comprising a gypsum base (1) connected so that the tooth model (2) can be attached and detached via a dowel pin (3) inserted into the connection hole (4),
An elastic ring (5) with elasticity, which expands and contracts by inserting a dowel pin (3), is embedded in the gypsum base (1), and this elastic ring (5) is inserted into the connecting hole (4). An indirect method working model in which the inner surface is elastically pressed against the surface of the dowel pin (3) inserted into the connecting hole (4), being fixed at a position inserted in the middle of the tapered dowel pin (3).   The indirect method working model according to claim 1, wherein the elastic ring (5) is embedded in the gypsum base (1) at a distance of 2 mm or more from the bottom surface of the gypsum base (1).   The indirect method working model according to claim 1, wherein the elastic ring (5) is embedded in the gypsum base (1) at a distance of 2 mm or more from the upper surface of the gypsum base (1).   The indirect method working model according to claim 1, wherein the material of the elastic ring (5) is one of soft plastic, natural or synthetic rubber. The indirect method working model according to claim 1, wherein the length of the elastic ring (5) is 1 mm or more and 5 mm or less.

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