A method of manufacturing a dental prosthesis and a device for its implementation

 

The invention relates to medicine, namely to prosthetic dentistry. Technical result: ensuring an exact match of the inner surface of the prosthetic base micro - and macro-relief of prosthetic bed, a uniform density of the base material, reduced polymerization shrinkage. The method consists in obtaining a mold with subsequent replacement of the wax prosthesis construction on the plastic by the method of injection-molding deformation. The pressure on the base plastic with the beginning of the polymerization is applied simultaneously from two sides: by injection channels inside and compressed air through the hole in the cell and the hole in the plaster of the mold through a porous plaster on the outside. The device consists of a modified detachable dental cuvette for receiving the mold containing the top and bottom between which is located a seal to create Hermeticism inside the cell. In the upper base of the cell there is a hole with threads for plugs, one end of which has the shape of a hemisphere, which is installed on the period for which the mold for forming grooves in plaster molds. In the following before starting the polymerization in this hole screwed by claim the basis of the cell has a mounting slot for connection with the syringe pressure (injector), and the bottom base of the cell is connected to thermocouple for the polymerization of plastics. Forming the basis of the denture plastic, plaster model of the jaw using a syringe press (injector) through the feeding gate system after melting the wax design basis denture wax feeding gate system. 2 N. p. F.-ly, 2 Il.

The invention relates to medicine, namely to prosthodontics.

The known method (C. N. Tregubov, M. H., Steinhart, M. M. Mishnev. Prosthetic dentistry. Applied materials. Saint-Petersburg. Publishing house “Special literature, 1999, S. 107) replacement of the wax design basis on the plastic, wherein forming the polymer-monomer composition is in a fluid state through a system of gates under the pressure created by a special piston (principle of the syringe). This method of replacement of the wax on the plastic got the name of the method of injection-molding extrusion. The injector plunger during the polymerization is under compressive action of the spring, from plaster into the cavity of the mold through the sprue receives an additional amount of the molding material,zemnoi cuvette, there is a risk of incomplete filling hard-to-reach places moldable material. In addition, the mold is made of plaster with porous structure during the molding of the plastic material in flowable state under high pressure piston prevents the penetration of the monomer from the polymer-monomer composition in the surface layers of gypsum, there is polymerized. On the inner surface of the prosthesis is formed roughness, distorting its macro - and micro, which significantly reduces the functional efficiency of the finished design.

There is a method (Khoroshilkina F. J., persin HP Orthodontics. Treatment subcluster-facial anomalies modern orthodontic appliances. Clinical and technical stages of their manufacture. Moscow, LLC “Orthodent-info”, 1999, S. 58-59) polymerization of the plastic material under high pressure, the sequence of implementation of which is as follows:

1) plaster model of the jaw or a cuvette with the mold placed in polymerization filled with water to 3/4 of its capacity with water at room temperature;

2) hermetically close polymerization;

3) raise the pressure up to 2.5 to 3 atmospheres;

4) the prosthesis is kept in polymerizate under pressure is shut, polished.

As polymerizate use an airtight vessel in which it is possible to create pressure. Most use the pan-the pressure cooker, autoclave small size (prototype).

This method however, despite the complexity of the technology, does not provide high-quality dental prostheses, because it does not solved the main problem:

- During the polymerization pressure is applied from the environment, only on the external surface of the cell (in the case of polymerization in the mold), and not directed to molded mass, the effect of the pressure of the compressed air is greatly reduced.

In the case when there is no mold, prosthetic base that penetrates the water, the slight negative pressure arising due to polymerization shrinkage, enhances these processes. After removing the pressure, air and water are excreted to the outside, breaking the density of the surface layer of the prosthesis.

The polymerization in aqueous medium, although at high pressure does not reduce the amount of residual monomer in the base of the prosthesis.

For molding method of molding plastics acrylic group created a number of devices made in the form of a syringe and a special cuvette. Sprv the cover of the cell holes for installation of the syringe and the input of the plastic mass. Inside the molds are molded channels for supplying plastic to the socket of the prosthesis. By means of a spring, available in syringe-the press, the piston is constantly presses on the mass, therefore, the polymerization it is held under constant pressure (Century. N.Kopeikin, L. M. Demmer. Prosthodontic appliances. Publishing house “Triada-X”, Moscow, 1998, S. 114).

The pressure on the material of the base during molding and polymerization is applied at different time intervals and alternately, so the above method does not provide a sufficiently dense structure of the prosthetic base, not reduced sufficiently polymerization shrinkage. The closest technical solution is US No. 5302104 published 12.04.94 “Device for forming the base plastic denture”.

1. The device for forming the base plastic of the denture by entering the molten plastic contains:

- a table that can ascend and descend along several vertical guide rods;

- lifting mechanism for lifting the specified table.

the upper supporting element, passing horizontally through the upper end of each of these guide rods and having a through hole;

- section for the corresponding item;

- pushing spring located in the specified partition for the spring;

piston rod, placed in a designated a through hole directed downward specified by the pushing spring and having a plastic sealing piston in its lower part;

- cuvette containing the basic form of the prosthesis that is placed on the table and having an opening for filling plastic in its upper part;

the cylinder having a passage for the plastic that connects with the specified fill hole plastic on its bottom wall and located below the piston; and

- breaking pressure element inside the specified cylinder, so that the breaking pressure element covers the specified passage for the plastic material; and

- wherein said piston rod has a thrust surface which abuts against the locking element when the piston is pushed against the elasticity of the spring to fully venutolo provisions specified fixing element is fixed relative to the upper support element.

2. The device under item 1, in which the breaking pressure element is designed in the form of a plate of metal or plastic.

3. The device under item 1, in which the breaking of DNA plate is made of aluminum and has a thickness of 0.1 to 0.6 mm and is broken when the force of pressure of about 500-5000 kg (102-1020 kg/cm2).

5. The device according to p. 3, in which at least the lower part of the said container is made of aluminum and has a thickness of 0.1 to 0.6 mm and is broken when the force of the pressure of 500-5000 kg (102-1020 kg/cm2).

6. The device under item 1, in which the specified thrust surface is the upper surface of the specified sealing piston and said locking element is a sliding sleeve, which runs from the lower surface of the specified upper supporting element.

7. The device under item 1, in which this spring is made so that the above fully retracted, when the locking element is in contact with the specified thrust surface, the spring produces an initial outward pressure that is less than the pressure required to break the breaking pressure element and the breaking pressure element is designed so that the further the pressure is less than the initial sufficient to break the item, the further the pressure force is provided by further lifting the table with lifting mechanisms.

In this case, the device for forming the base plastic prosthesis is intended for the introduction of a thermoplastic plastic, which must be R the ith considerable effort for rapid filling of the mold molten thermoplastic plastic: the presence of rising table, an elevating mechanism for him, guide rods, springs, elements, breaking under the pressure, and so on, Despite the complexity of the device, the pressure on the base plastic in the end is superimposed only on the injection channels from the inside of the mold and does not solve the main problem: overlay simultaneous pressure on the material basis from the inside of the mold through the injection channels and out through the porous plaster molds.

The technical result

Ensuring accurate matching of the inner surface of the prosthetic base micro - and macro-relief of prosthetic bed, a uniform density of the base material, reduced polymerization shrinkage, the amount of residual monomer, increasing the functional efficiency of the treatment.

This is achieved due to the fact that in the process of manufacturing bases dentures by casting under pressure syringe pump (injector) after molding is not detached from the cell, and the pressure on the pre-formed polymer-monomer composition since the beginning of the polymerization begins to occur on the basis of the future prosthesis simultaneously: on the one hand by injection channels by type casting the additional pressurizing and on the other hand the compressed air through a porous plaster press gives the need to use a sealed container with water, because cuvette has its own thermocouple and the polymerization is carried out by type of directed. The compressed air entering from the compressor, the inclusion of water.

Pressure applied directly on the material basis of the prosthesis on its external surface with compressed air through a hole in a ditch, a hole in the plaster mold and the porous plaster mold, prevents the penetration of the monomer in the surface layers of plaster, and the concomitant pressure on the base material by injection molding channels and compressed air from the outside provides the necessary density plastics, especially in the outer layers of the base due to constant pressure from the piston syringe-press (injector) is complemented by a number of plastic compensate for polymerization shrinkage, guaranteed conservation of volume and strength basis, liquidated porosity in tight for forming zones. Due to the fact that the proposed device is intended for forming the polymer-monomer basic composition, and polymerization of basis is performed after molding, the device entered thermocouple provides temperature molding and polymerization of the plastic. To perform all these technological ATPC, and in the upper base of the cell has a socket for connection with the syringe pressure (injector) and a hole with threads for plugs, one end of which has the shape of a hemisphere or valve for compressed air.

Thanks to the use of directional dry-heat of polymerization, which provides thermocouple decreases the amount of residual monomer in the base of the prosthesis. Cuvette for receiving the mold, the proposed method applies the split with seal at the parting line that provides the necessary Hermeticism inside the cell. This method dramatically changed the principle forming the basis of the prosthesis and subsequent polymerization of the base plastic, simplified and reduced the price of the technology basis.

Thus, changing the basic technological parameters of formation and polymerization of the base plastics: pressure, temperature, place of application, you can manage the process of shrinkage, density and receive the prosthetic base with dimensions given accuracy. The proposed method can also be applied in the manufacture of fixed constructions of dentures, which are applied acrylic polymers, repair of dentures, the manufacture of removable orthodontic appliances.

On the FIA upper base of the modified dental cuvette.

The device consists of a modified detachable dental cuvette for receiving the mold (12), a top (2) and bottom (3) of the base, between which is located a seal (4) to create Hermeticism inside the cell. In the upper base of the cell there is a hole with thread (6) to insert one end of which has the shape of a hemisphere (7), which is installed on the period for which the mold (12) for forming grooves in plaster molds (10). In the following before starting the polymerization in this hole is screwed to the valve for compressed air (not shown). The top and bottom of the cell are connected by three bolts (8). In the upper base of the cell has a mounting slot (11) for connection with the syringe pressure (injector) (1) and the bottom base of the cell is connected to thermocouple for molding and polymerization (9).

Forming the basis of the dental prosthesis (5) plastic, plaster model of the jaw (14) is carried out using a syringe press (injector) (1) through feeding gate system (13) after melting the wax design basis denture wax feeding gate system.

Specific example

Wax design a prosthetic base (5) with ustanovlenytakie (4), before receiving contrastano in the upper base of the cuvette into the hole with the nut (6) screw cap, one end of which has the shape of a hemisphere (7), for forming grooves in plaster molds (10). After receiving the mold (12) remove the wax from her and feeding gate system (13) a method of melting, followed by isolation Gating of the channels and the inner surface of the mold with the use of alginate varnish. The upper (2) and lower (3) the base of the cuvette connect the three bolts (8). On the upper base of the cell (2) in the mounting slot (11) establish a syringe pump (injector) (1).

Next, prepare the molding polymer-monomer composition, fill it with the loading chamber syringe press (injector) (1), produce the base molding plastic in a plaster mold (12). Unscrew the cap, one end of which has the shape of a hemisphere (7), and which played a formative role in the creation of the notches in the plaster mold (10) for distribution of compressed air and save space for the valve (not shown), connect the hose to the compressed air through the valve, screwed into the hole in the upper base of the cuvette (not shown). With the beginning of the polymerization impose pressure on the material basis of dental pressure outside through a valve (not shown). Next, perform a directed polymerization of the plastic at a temperature of 60With over 75 minutes Cast finish pressing the hold during the polymerization 2-3 times with a break of 20 minutes After the end of polymerization, the device is slowly cooled in air and further steps are carried out by well-known methods of processing dentures.

In the proposed method combines traditional technology and modern methods of injection molding, the molding technology held in conjunction with the polymerization of the base plastic.

Distinctive in technology is that molding the pre-pressing of the base plastic is in the final stages of the molding at elevated temperature, which contributes to a better form, a uniform density of the material basis of the prosthesis, the reduction of internal stresses, compensate for polymerization shrinkage.

Technical and economic effect

Method and device experimentally selected, tested in practice. Using the proposed method for the manufacture of dental prostheses and devices for its implementation in 2000 made 35 removable laminar dentures with politicalparties, no complications.

Registration of the application for an invention simultaneously in the method and the device are dictated by the need, because in this case the method and the device are impossible without each other.

The list of names to Fig.1. 2.

1. Syringe pump (injector).

2. The upper base of the cell.

3. The bottom base of the cell.

4. Ring.

5. The basis of the dental prosthesis.

6. The hole is threaded in the upper base of the cell.

7. Bracket, one end of which has the shape of a hemisphere for forming grooves in plaster molds and save space for the valve.

8. Bolts to connect the upper and lower base of the cell.

9. Thermocouple for polymerization of the base plastic.

10. Dent in the plaster mold.

11. Mounting slot in the upper base of the cell for connection with the syringe pressure (injector).

12. Press form.

13. Feeding gate system.

14. A plaster model of the jaw.

Claims

1. A method of manufacturing a dental prosthesis, which consists in obtaining a mold with subsequent replacement of the wax prosthesis construction on plastic using injection molding method, polymerization of the dental prosthesis, wherein d is m the air through a hole in a ditch and the recess in the mold through a porous plaster on the outside.

2. Device for the manufacture of dental prostheses containing cell, removable syringe pump (injector) to inject the plastic into the mold, characterized in that the cuvette is made detachable, and the parting line between the upper and lower base of the cell has a seal that maintains the seal in the upper base of the cell has a socket for connection with the syringe pressure (injector) and a hole with threads for plugs, one end of which has the shape of a hemisphere, or valve for compressed air, while the bottom base connected to thermocouple for thermal regime formation.

 

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EFFECT: high quality of dental prostheses containing no defects.

7 cl, 2 dwg

FIELD: medicine.

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5 dwg

FIELD: medicine.

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2 dwg

FIELD: medicine.

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FIELD: medicine.

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1 dwg

FIELD: medicine.

SUBSTANCE: before the teeth removal, a pattern of both jaws is contoured. That is followed by casting against the pattern. Electromyography is performed to examine the health of the masseter and cervical muscles to be relaxed by transcutaneous electronic nerve stimulation therapy in order to identify the optimum position of the lower jaw. The post-relaxation health of the muscles is controlled by electromyography, and this position is recorded. Thereafter, these findings are used to fix the patterns into an articulator with pre-set angles of sagittal and transversal slide paths. The anatomical shape of the crown portion of the tooth to be removed is contoured in wax. Then a thermal forming plate of a desired thickness enabling to restore an occlusal vertical dimension to a desired value is selected; a basis is formed in a thermal forming unit. It is snipped of in the form of a tray. The tooth to be removed according to the common technique is cut off on a plaster contour. Quick-setting plastic is introduced into the tray cell of the removed teeth to restore the defect; contacts of the prosthesis and antagonist tissues are aligned in the articulator. The prosthesis is finished.

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EFFECT: higher quality of product, higher safety and simplification of furnace operation.

16 cl, 11 dwg

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