WO1986002259A1 - Process and device for the production of dental prostheses or parts thereof from polymerizable plastic - Google Patents

Abstract

The process is designed for the production of dental prostheses or parts thereof from polymerizable plastic. The easy-flowing plastic is introduced into a hollow area (3') which corresponds to the shape of the prosthesis, limited on the one side by the plaster cast (3) and on the other side by an upper mould section (4) which maintains the tooth arrangement (14) and altogether surrounds the free surfaces of the plaster cast (3). In a polymerization vessel (1) the plastic is polymerized in a bowl (2) which contains the plaster cast (3) and the upper mould section (4). In order to improve the matching precision of the prostheses produced, a lower pressure than that of the other also locally-open regions is applied through one or several open points (6) on the underside of the base of the plaster cast (3) at the latest during polymerization of the plastic.

Description

Method and device for the production of dental prostheses or prosthesis parts from polymerisable plastic

The invention relates to a method and a Vorrich¬ device for the production of dental prostheses or prosthetic parts of polymerizable plastic according to Oberbe¬ handle of the main claim.

Such a method is known from FR-PS 1 077 993. In this case, the polymerization pressure is imparted by mechanical means to the plastic contained in the cavity and introduced in a certain amount by a bladder which is pressurized and arranged in the cuvette, which can come into contact and become effective only in the cavity area within the tooth position that a gap formation by shrinkage of the plastic in the remaining areas (labial / buccal) is nothing contrary, which is foreseeable even worse than if no measures at all against such a gap formation 'would be made. Apart from the difficult handling of this known device, namely, the pressure in these remaining Berei¬ chen effect only from the side, but with a gap formation by shrinkage of the plastic can not be counteracted. In other known methods of this type, which can not be documented by letter, the flowable plastic is converted into a mold corresponding to the shape of the prosthesis, on the one hand by the plaster model and, on the other hand, by a tooth trimming and holding

In the open space of the plaster model, the surrounding hollow space is encapsulated and polymerized in this form in a tempered polymerization bath. This previously known method has compared to a likewise known, so-called injection method, in which the plastic in exclusively from plaster. Hende hollow molds is introduced, the advantage of a much lower expenditure on equipment and in particular the significant labor savings. However, this method is loaded with the disadvantage that the shrinkage of the plastic has an effect on the surface of the plastic and also covers it, which bears directly against the plaster model. For this reason, when removing the plaster model from the cuvette and after removal of the doubling gel, a considerable gap between the polymerized plastic and the gypsum model surface, ie, the palate or jaw contact surface of the formed one, usually appears - Polymerized plastic palatal plate does not agree ex¬ act with the impression. For this reason, this method has not proven to be simple and, because of its simple handling and apparatus which is not very complicated in terms of apparatus. In the case of the above-mentioned injection-molding process, the plastic is pressed into the cavity of the prosthesis production mold in a more or less doughy form and, with regard to its polymerization, is adjusted so that only slight shrinkages occur. Although it is thus possible to largely prevent the formation of gaps, the formation of pressure under stress makes it unavoidable in the prosthesis molding that can subsequently lead to stress cracks or deformations when the prostheses are worn. Thus, with the previously known method, a gap formation caused by the shrinkage of the plastic and thus the accuracy of the prosthesis must be tolerated or, with a reduced gap formation (injection method), a tension formation in the prosthesis.

The invention is therefore an object of the invention to form a method and an associated device to the effect that while maintaining the simple Manageability of the disadvantages of the non-precise fit polymerisability of the plastic is remedied, ie the method and the associated device are to be improved so that the auspoly erized prosthesis molded body largely exactly abge¬ squeezed entire jaw shape and thus the plaster model and remains tension-free.

This object is achieved by a method of the type mentioned according to the invention by the features cited in the characterizing part of claim 1. Vorteil¬ advantageous developments of the method will become apparent according to the accompanying subclaims 2 to 4.

Depending on the plastic used, it is even possible to dispense with external pressure and thus a polymerization vessel, since in many cases sufficient pressure for sufficient polymerization suffices. As has been shown, this method according to the invention is as simple as it is surprising in its result, because solely by providing the gypsum model with a lower pressure than the ambient pressure during the polymerization, the shrinkage takes place exclusively only in the direction of the gypsum model surface to, but this means nothing else than that the whole plastic molding remains applied to the gypsum model surface during the polymerization process. It should be noted that the size of the shrinkage in the area of the occlusal surface is only noticeable in the range of tenths of a millimeter. The risk of occlusion deviations of the tooth position in well-defined pines is relatively low, regardless of this, however, in view of this the method can advantageously also be further developed to the effect that the tooth position in on the gypsum model during the polymerization is kept in constant occlusion distance to the gypsum model. This and the apparatuses suitable for this purpose will be explained in more detail.

The method according to the invention is suitable both for cold- and for heat-polymerisable plastics, although the model top part may of course not consist of a doubling gel but of suitably temperature-resistant silicone rubber or, since much less expensive, preferably gypsum, especially gypsum security against Occlusion deviations ensured ge and in this regard no special measures such as Doubliergel or silicone must be taken. Apart from that, of course, there is nothing to verwen¬ a top made of gypsum also for cold polymers. The necessary other measures will be explained in more detail below.

As far as the plastics to be processed by the process ^* are concerned, they must, of course, be readily flowable in order to be able to reach and fill all regions of the model cavity as well. Of course, such free-flowing plastics were also required in the introductory single method mentioned above; However, in order at least approximately to take into account the shrinkage behavior, work was carried out with polymers which swelled only slowly, which, as is known, led to poor physiological properties of the finished prosthesis (water absorption, brittleness or risk of breakage, white discoloration). Since the process of the invention takes account of the shrinkage effect in a different manner, it is preferred to use polymers which are readily soluble in the monomer for carrying out the process and wherein, due to the flowability or pourability, a comparatively higher monomer content is present. Such a mixture, which is further defined, is characterized by high density, good elasticity, color fastness and minimal water absorption capacity on the end product. The device suitable for this method is explained in more detail in the special part of the description.

The stated task can also be solved in another way, namely according to the independent claim 11th

In contrast to the first solution, in the case of this second solution, it is possible during the polymerization to press out plastic into the cavity of the mold from a small plastic or- ganate, which is centrally arranged in the production mold and thus heat-shielded, and which is kept under pressure during the polymerization and in this way to compensate for the shrinkage, whereby it can also be considered to combine both methods. Although this second method is particularly suitable for unfavorable jaw conditions (flat alveolar ridges or irregularly high sclera combs), it can also be used without difficulty for well-defined jaws and is thus more universally applicable. The device suitable for this second method is also explained in more detail in the special description section.

Both methods of the invention require, measured by the success, only a relatively small expenditure on equipment, are easy to handle (the plastic can be simply poured into the production mold in the pourable state) and the results are completely satisfactory, ie, there are prostheses with previously unattainable high accuracy of fit, both with regard to the jaw contact surfaces and with regard to the tooth position.

The two methods, the associated devices for carrying them out, practical and advantageous embodiments will be explained in more detail below with reference to the drawings of exemplary embodiments.

It shows schematisσh

FIG. 1 shows a polymerization vessel with a cuvette arranged therein; FIG. 2 shows a section through a particular embodiment of the cuvette;

Fig. 3 is a side view of the open

cuvette; 4 is a plan view of a particular embodiment of the cuvette base plate; FIG. 5 shows, in section, the cuvette base plate according to FIG. 4; FIG.

6 shows a side view of a further embodiment of the device;

7 shows in section a particular embodiment of the cuvette; Fig. 8 shows in section the upper part of the device during the formation of the chicane;

Fig. 9 shows a section through the upper part of the device according to FIG. Figure 2 with the applied chicane and already eingochenem filling channel. 10 is a side view of the prosthesis production mold for the second process in a cuvette during filling of the flowable plastic; 11 shows a section through the cuvette according to FIG. 12 with the prosthesis manufacture inserted therein. FIG. lung form;

Fig. In section, different embodiments of

12 to 15 centrally arranged in the casting mold

Casting container and Fig. 16, the arrangement of the cuvette in a Druckpoly¬ merisationsgefäß.

»

First, the first method is explained with reference to FIGS. 1 to 9:

As can be seen from FIGS. 1, 2, the cuvette 2 consists of the base plate 5 and the cuvette upper part 16, which can be releasably fixed to the base plate 5 with clamping holders 19. The large opening 17 is used to pour the Doubliergelmasse, and the smaller openings 17 'are used to escape the air during pouring the Doubliermasse. By means of side elements 20 arranged laterally on the upper part of the cuvette 16, the cuvette 2 for the pouring of the plastic into the filling funnel 18 can be placed vertically, with which vertical position the cuvette is also introduced into the polymerization vessel 1 according to FIG. Since the gypsum, modeil is porous. 3, it is sufficient, according to Embodiment Fig. 1 in the base plate an opening to mount 6 and ^'connect these öff- voltage with a conduit 8 with the surrounding atmosphere of the polymerization vessel 1, wherein, as shown in Fig. 1 schematically indicated, at the end of a vacuum generator 9 'may be connected. Opening 6, line 8 and vacuum generator 9 'form the differential pressure chamber in this case. More advantageous, however, is the embodiment according to FIG. 2, in which the opening 6 of the base plate 5 only leads to a chamber 9 which is likewise arranged in the base plate 5 and forms the differential pressure chamber. In this embodiment, namely, a connection of the opening 6 to the ambient Atmosphere of the polymerization vessel 1 is not erforder¬ Lich, as in the chamber 9 atmospheric pressure prevails and so far a sufficient Differenzdruckverhält¬ nis to the entire interior of the polymerization vessel

.5 1, which is provided with a suitable heating device 21. In order to exclude a pressure equalization between the inner space of the polymerization vessel 1 and the chamber 9 "(this also applies to the opening 6 in the case of the example embodiment according to FIG. 1),

10, the self-given sealing surface between the doubling gel forming the model top part 4 and the surface 1 ^~ outside of the seating area 7 of the plaster model can additionally be prevented by sealingly sealing the base plate 5 around the model fitting area 7.

15. Flächenvergrößerndes element is arranged, and indeed, as shown in Fig. 2, in the form of a groove 10 and / or a web 11. This additional seal can of course also be provided in the embodiment of FIG.

20

Although deviations from the necessary occlusion distance are slight in the first method, when using a more or less elastic modular part 4, this can be counteracted by simple means.

25 are knitted, as is also hinteu¬ in Fig. 1 tet. For this purpose, a so-called occlusion stabilizer 12 is provided on the base plate 5 of the cuvette 2 outside the gypsum model attachment region 7 and can be fixed so that at least the entire tooth position 14 of FIG

30 prosthesis surrounds and covers them at close range. As it has been shown, the arrangement of such a stabilizer which stabilizes or stiffens the doubling or silicone mass forming the upper part 4 in the critical region is sufficient, and thus occluder

35 lesions of tooth position 14 prevented. Between the tooth stocking and the stabilizer 12, however, it is also possible, when using a doubling gel, to arrange a suitable holding mass, for example a silicone compound, and to integrate the whole into the doubling gel during the preparatory operation. This occlusion stabilizer 12 is formed, for example, from a plate provided with holes 15 or a sufficiently stable grid, in consideration of the flowthrough capability with the doubling mass, as shown, the area below the opening 17 of the cuvette top part 16 is freehal th.

In the embodiment of FIGS. 4, 5, the chamber 9 is replaced as a differential pressure chamber in a simple manner by a recess 25 open to the gypsum model with support webs 27 in the attachment surface 26 from which _, small openings 6 lead to a connection channel 23, the vakuu connection tig is equipped with a check valve 22 and at the other end with a vacuum indicator 24 in the form of a membrane. These elements, ie valve 22, connection channel 23 and vacuum display 24 can of course also be provided in the embodiment of FIG. After uncoupling a corresponding vacuum device, the check valve 22 blocks a pressure equalization and the vacuum display 24 in the form of a membrane (provided with a small An¬ show cam 24 ') makes clear to the user that the whole is for the polymerization under vacuum, the expedient is already set before the plastic is poured into the cavity. In this way, the doubling gel mass is seated absolutely tightly on the contact surface 26 of the base plate 5. The simplest possibility of carrying out the process or realizing the differential pressure is to apply a cavity in the plaster model base or in the cuvette base plate during through-polymerization frequently leads to a lower pressure in the gypsum model. Since it is expedient for rational reasons, advantageously a plurality of suitably prepared cuvettes 2 are polymerized simultaneously in the polymerization vessel 1. For this reason, there is a vorteil¬ refinement of the device according to Fig. 6 in the above-mentioned elements 22, 23, 23 ', 24 common in a carrier ge ** 2 ^~ to arrange cuvette sealed on the suitable means and with ge individual cuvettes 2 with their openings 6 or connecting channels will put on.

Referring to FIG. 4, it should be noted that the recess shown there 25 even ^"may be sufficient alone to create a ^* differential pressure chamber, in wel¬ chem case, therefore, the free opening cross section of Ein¬ deepening 25 forms as it were the opening 6 itself. The embodiment according to Fig. 7 refers to the use of plastic material to be hot-polymerized, since the temperatures are above 50, no doubling gel can be used for the top model part 4, but silicone rubber composition is used. which on the one hand is more cost-effective and in which no occlusion deviations are to be feared for the tooth stock 14. However, special measures must be taken to ensure that the process condition of the differential pressure formation in the device variant according to FIG the rest are also considered to belong to the gypsum model 3 and model upper part 4 considered) is also fulfilled. For this, the raised plaster model 3 with the wax model up to the modeling edge 28 is surrounded with silicone rubber as sealing compound 29 and the wax model is covered with a thin layer 30 of the same mass. After that will the free space of the cuvette top 16, which in this case is completely open at the top, filled with plaster, which then forms the model top part 4. After Ausfül¬ the wax model len thus there is intended for the carrying out the method with hot polymerisate device out of the cuvette 2, disposed therein, all around surrounded by sealant 29 plaster model 3 and out of the upper part 4 (also from gypsum), wherein ^* but its cavity-side surface is also provided in a thin layer 30 with the sealant 29. The thin one

Although layer 30 is not necessarily required for the function of the first method, since the plastic introduced into the cavity itself acts as a sealant with respect to differential pressure formation between plaster model 3 and model top part, but the thin layer is advantageous in that Once the differential pressure can be applied even before the introduction of the. Plastic, but on the other hand da¬ by the entry of foreign media from the Modellob-part 4 is prevented in the plastic mass. Moreover, a particularly expedient embodiment of the base plate 5 can be seen from FIG. 7, which can also be used in the embodiments according to the other figures. In this case, a recess 31 is provided in the base plate 5, is entered into the plaster 32 as up, sockelmasse for the gypsum model 3. As a result, on the one hand, the plaster model 3 does not have to be ground flat prior to introduction into the cuvette 2 and, on the other hand, optimum conditions are achieved with regard to an already substantially leakproof connection. Since the opening 6 must also be found here in the base plate 5 in order to be able to carry out the first method, the opening 6 is provided with a small support grid 33 because of the plaster cast, whereby the plaster is then poured in 32 still a filter paper disc 34 a is placed.

With regard to the plastic for the finished prosthesis 13 (FIG. 2) to be used in the first method, the following mixing ratio has proved to be particularly advantageous:

10 parts of a rapidly soluble in the monomer

Polymers and 20 parts of monomer. Optimal and most economical, however, is a liquid polymer-monomer mixture which can be processed directly in its form of delivery. Although these mixture preparations per se shrink strongly, they can nevertheless advantageously be used thanks to the described method of operation, since all means are used to ensure that a differential pressure is present on the prototype part to be formed on the plaster model side.

As has been shown, the above-described first method leads on the one hand to very good results, but on the other hand the pouring region of the device has proved to be problematic insofar as the plastic filling the funnel 18, which in itself has nothing to do with the shaping of the Prosthesis has to do, of course, also undergoes a shrinkage in the polymerization. It should be assumed, however, that the mold part 4 is under pressure during the polymerization, that its material also adheres to the shrunken plastic _. ^* in the funnel, regularly and everywhere, however, this certainly does not always guarantee, especially since it must be remembered that the gypsum model 3 is under lower pressure. It must also be considered that, in the unfavorable case, the pouring channel located in the upper part 4 can open out in relatively close proximity to the plaster model 3. Although these conditions do not lead to negative results with regularity, it is occasionally found that the lower pressure on the gypsum model collapses and water entered into the cavity 31 has to be detected, which of course adversely affects an optimal result of the prosthesis formation. Ultimately, this can only be explained by the fact that, due to the shrinkage of the plastic on all sides, the gap forming there is not or not completely closed in the pouring channel and pressurized water can enter from the polymerization vessel 1 or a pressure equalization between the pressure-different spaces er¬ follows.

This problem can be solved with relatively simple means, namely by virtue of the fact that at least in the area of the hopper 18, at least one circumferential sealing strip 36 is formed on the upper mold part 4 arranged in the cuvette 2. Part 4 shaped sealing lip, is arranged. As has been shown, this basic and simplest embodiment already leads to success, since apparently this at least one chicane is sufficient to stop the water entering the chicane under unfavorable circumstances and to prevent a pressure equalization.

In the region of the pouring opening 35 of the hopper 18 is now with reference to Fig. 8, 9 in the upper mold part 4 a circumferential Entungsschikane 36 is arranged, which, as shown, is formed from the material of the upper mold part 4 and forms a circumferential sealing lip. The plastic to be introduced into the cavity 3 'is, of course, poured in until it ascends to the upper cuvette edge of the opening, ie The plastic 36 also flows around the baffle 36. The shaping of this baffle 36 is conceivably simple, since a correspondingly profiled rubber stopper 42 is inserted into the corresponding opening of the cuvette 2 before the pouring in of the doubling compound, which forms the upper mold part 4 Solidification of Doubliermasse can be removed so that it receives a shape in section, as shown in Fig. 9. The pouring channel, which extends to the cavity 3 ', is cut with known channel engravers. The pouring channel is only indicated by dashed lines in FIG. 8, since this is not yet present in this production phase. The cast-in plastic is illustrated in dotted lines in FIG. 9, wherein it also becomes clear from this representation that the ski 36, of which of course several (indicated by dashed lines) can be provided in the direction of the cavity 3 ', enters is a major obstacle to the entry of pressurized water or a pressure compensation. It should be noted that the magnitude of the forming column is only fractions of a millimeter. When using silicone rubber for the upper mold part 4, the pouring channel 18 can not be pierced, for which reason before pouring the silicone rubber into the cuvette (the pouring of both the Doubliermasse and the silicone material is of course basically An¬ order of the wax model on the gypsum model. 3 ) ein¬ sets a wax mold corresponding to the desired channel shape ein¬ and this with. This results in the. Possibility to form this wax molding so that it has in the channel area corresponding circumferential baffles 36.

The second method will now be described with reference to FIGS. 10 to 16, for which reference numbers from 50 are used: In this method, plastic is thus pressure-less ein¬ fold poured into the respect to their occlusal plane perpendicular mold in a mold with integrated cavity, which is thus in the center of the overall model and only from there the plastic passes through Eingießkanäle 53, 53 ' into the cavity 54, as shown. Since the model cavity 54 fills from the bottom to the top, the upper inlet channels practically serve only as venting channels, whereby it is advantageously ensured using a correspondingly formed funnel 61 that the pouring at the lowest point of the central hollow space or on the pouring channel located there. 53 'er¬ follows. The pouring of the plastic takes place until the central cavity has also filled, which is then placed under pressure-tight closure in a suitable manner during the polymerization in the polymerization under pressure. Since in the polymerization bath 78 the heat flow (see arrows in Fig. 16) with respect to the casting model from the outside inwards, the central cavity or the Eingießbehälter 52 and the radially emerging therefrom Eingießkanäle 53 from the advancing Wärmefront, the polymerization causes, last detected, so that in practice, since the whole is under pressure during the polymerization, the still flowable plastic can be pushed out of the central cavity. The prostheses her¬ made by this method not only show ^* the high Paßge¬ accuracy in the contact surfaces, as in the first method, but also the position of the teeth was itself obtained according to the model in ^'cases where ferverhältnisse unfavorable silicic so strong Plastic concentrations in total or at specific locations under the Zahnstel¬ ment. This second method is therefore particularly suitable for such cases, but with which it should be concluded that the second method can also be used for the production of prostheses for well-shaped pines. In that regard, the second method can also be used in combination with the first method.

Under the pouring container 52, one does not have to imagine a large container, but rather a small container.

3 nis with a recording volume of 3 to 4 cm, which is readily accommodate in the center region of the upper or lower part 50, 51. For the devices 55 for generating an internal pressure, there are the most varied possibilities, but it is only a question of producing a displacement effect with respect to the plastic contained in the pouring container 52 on the condition of a pressure-tight closure of the pouring container 52.

Of course, the pouring container 52 with its channels 53 and with the closure lid 56 are not reusable appliances, but elements which belong directly to the prosthesis production mold and which, just like the production mold themselves, have fulfilled their task after completion of the prosthesis and are discarded can.

As can be seen in particular from FIG. 11, the prototype preparation for carrying out the method consists of the model top and bottom parts 50, 51 arranged in a cuvette 62 and enclosing the prosthetic cavity 54 to be extracted. The pouring container 52 is centrally integrated in the model top part 50 of which a plurality of pouring channels 53, as shown, are guided in a radial manner (see FIG. 10) to the prosthesis cavity 54, which essentially extend in a plane downstream of the sides to the prosthesis cavity. cavity 59 extend out. Since, in the present case, pressure is exerted internally on the filled plastic during the polymerization, and thus the entire mold is under internal pressure, the cuvette is equipped with suitable clamping devices 63 in the direction of FIG. 11, which, however, in consideration on the pressure in the polymerization vessel (FIG. 16) only has to absorb the differential pressure. The centrifuge in the form ange¬ arranged pouring 52 is simply in the manufacture of the relevant molding in this eingebun¬ the and in such a way that the ends of the seated on Eingießbehälter 52 pouring 53 extend to the cavity 54. If necessary, necessary reworking on the relevant molded part in order to expose the outlets of the pouring channels 53 can be accomplished without difficulty. The cover plate 63 'of

Incidentally, the clamping device 63 fully covers the opening 66 in the cuvette wall, wherein the volume of the opening 66 is also completely filled with the material of the upper part (for example a doubling gel or relevant model mass).

The filling of the pourable plastic which can be polymerized under the action of heat and pressure takes place in a position of the entire casting mold according to FIG. 16, ie with a vertically oriented occlusal plane. For the filling of the plastic, a funnel 61 with a correspondingly long pouring shaft is used, which is placed on the pouring channel 53 ', which extends vertically downwards from the pouring container 52. This ensures that the plastic flows into the cavity 54 at the lowermost point and from there ascends the air from the cavity through the above-mentioned still free pouring channels 53 (actually ventilation channels), as shown in dashed lines indicated, can flow out. It is understood that the two uppermost runners 53 at the highest points of the hollow be set 54 space. If during the filling process of the plastic this begins to show in the pouring 52, the Ein ießvorgang is completed and the hopper 61 is herausge¬ herausge¬ from the pouring 52, which is then sealed in a pressure-tight manner with a lid 56. In order to throttle the heat flow from this side, the lid 56 is formed of poor thermal conductivity material and kept sufficiently long.

In the exemplary embodiments of the pouring container 52 according to FIG. 12; 13, the lid 56 is provided with pressure ports 57 to pressurize the interior of the container 52 can. For this purpose, according to FIG. 12, a small piston 58 may be provided or a bubble 59 according to FIG. 13, which expands correspondingly upon pressurization and pressurizes the plastic located in the entire cavity, which itself is incompressible. The arrangement of the Eingießbehälters ^* 52 in the central region of the mold, the polymerize Rende warm front moves with respect to the Herstellungsforn from the outside inward and accordingly also cures the resin in the cavity 54 from outside to inside, so that respectively from the center forth from the pouring container 52, in the case of inevitable unavoidable polymerization shrinkage of the plastic, synthetic material is automatically pressed from the pouring container 52, which is indeed under pressure and is still liquid. This is of particular interest, as mentioned, for prosthesis molds, for example because of unfavorable jaw conditions, strong plastic masses, as can be seen in FIG. 11, are present where shrinkage occurs with respect to the tooth position 64 in the upper mold part 50 would be noticeably noticeable, as has been shown. It is thus possible by means of the second method described above. To produce prostheses that show optimal results both in terms of accuracy of fit to the jaw concerned as well as in terms of the maintained tooth position with respect to the actual prosthesis body. Of course, the second method described is not restricted to such extreme cases (which make up only about 20% of all cases), but of course it can also be used if well-shaped jaws are used as in the first method available. Insofar as feasible, one will place the Eingießbe¬ container 52 with its channels 53 and embed in the relevant model part that the channels are pos ¬ lichst on grσßvolu ige areas of the model cavity.

FIG. 14 shows a further embodiment of the pouring container 52, in which a pressure supply from the outside can be dispensed with. This is made possible by the fact that 59 ei propellant 60 is contained in a small bubble 56 located on the lid 56, and immediately before the cuvette is inserted into the polymerization bath 78 (FIG. 16) an agent triggering the propellant action For example, added by means of a small syringe and thus the whole system is pressurized.

Advantageously, the method can also be carried out in a further development such that additionally at least one open point 65 on the lower side of the base of the production mold will maintain a lower pressure than in the model cavity at the latest during the polymerization. This, to a certain extent, represents an additional safety measure, which ensures that the polymerisable plastic shrinks towards the base side and remains in a fitting fit with this molded part, which can easily be afforded, since the plastic fabric from the center area is under pressure and can flow in the extent of shrinkage.

In Fig. 15, a further embodiment of the pour-in is the container shown greatly enlarged 52, wherein the zy¬-cylindrical upper part 52 'in a flat bottom part 52 "form passes in adaptation to the geometrical conditions of the Modell¬. The small displacement piston 58 ^{* 1.} is seated on a guide pin 67 of the lid made of poorly heat-conducting material 56, which secures, for example, with a latching toothing 68 in the container upper part 52 'and is sealed off with a ring seal 69.

The lower part 52 "of the small Eingießbehälters 52 may also parabola with respect to its shape adapted to the course of the tooth position and ver¬ on its flanks 70 with at least one slot 71 (see FIG. 16) ver¬ which then forms the channels 53 and this The flanks 70 then run within the production form only a few millimeters away from the cavity 54, wherein the connection slot leading to the cavity 54 is formed in a suitable manner into the relevant molded part.

With respect to the above-mentioned to Fig. 13, 14, bubbles 59 still should be added that these are formed as small, tube-like bubbles, which are advantageous with a attached to the lid 56 expansion restraint grid ^'59 * surrounded, so that the bladder in the inflated state the slot 71 or the inputs to the channels 53 can not block.

In order to release excess plastic when the lid 56 is pressed into the filled pouring container 52. To be able to sen (air bubbles may not be present), in the lid 56 is advantageously still a small, to be closed after placing the lid overflow channel 73 is provided.

Since the plastic is in any case under pressure from the inside in the described second method, it is possible to carry out the polymerization simply in a pressure-free hot water bath vessel. However, preference is still given to the customary polymerization in a polymerization pressure pot 75 according to FIG. 16, which, however, requires a particular embodiment in such a way that at least one further upper part on the cover 72 or wall 74 of the pressure pot Druckleitungsdurchgriff 76 is arranged, through which from a pressure generator 77 with appropriate Leitungs¬ connections, the pressurization of the Eingießbehälters 52 takes place, unless in the bladder 59, the pressure is not generated by a propellant 60.

As can be seen from the description, in the second method, in contrast to the first method and to the previously known methods, the plastic mass which can be pressed into the cavity 54 for shrinkage compensation is introduced directly into the polymerization bath 78 with the production mold, but is in the opposite direction the heat effect is initially protected by the production form itself, since the plastic which can be subsequently pressed in is located in the center region of the production mold.

Claims

claims:

1. A process for the production of dental prostheses or prosthesis parts of polymerisable plastic, wherein the flowable plastic in one of the Pro¬ thesenform corresponding, on the one hand from Gipsmo¬ dell and on the other hand by a tooth set-holding and the free surfaces of the plaster model ins¬ total surrounded surrounding upper mold cavity introduced and in a cuvette containing the gypsum model and the Form¬ is polymerized under pressure in a polymerization vessel, ¬ characterized in that over one or more open location (s) on the base bottom of the gypsum model at the latest during the

Polymerization of the plastic a lower pressure than the other, also locally open Berei¬ surface of the cuvette pressure is maintained.

2. The method according to claim 1 for the hot polymerization, d a d u r c h e c e n e c e s that used as upper mold part such a gypsum and this for pressure equalization prevention during the Heißpol merisation against the maintained on the gypsum model (Formund terte) lower pressure by means of a thin layer of sealant is kept shielded.

3. The method according to claim 1, dadurchge - characterized in that the tooth set-up in the upper mold part with respect to the gypsum model (Form¬ lower part) during the polymerization by Abschir¬ determination and / or holding entanglement holding ge is kept.

4. Method according to claim 1 or 3, characterized in that the gypsum model (mold bottom) and the cavity to be cast are placed under vacuum before, during or after the filling of the plastic.

5. Apparatus for carrying out the method according to claim 1, consisting of a cuvette with Grundplat¬ te and with the auszießenden cavity limiting gypsum model and Formoberteil, dadurchge ¬ indicates that in the base plate (5) of the upper mold and that on the base plate (5) arranged gypsum model (3) receiving cuvette (2) at least one opening (6) in Gypsummodellaufsetz- area (7) arranged and this opening for Aufrecht¬ preserving a relation to the pressure on the upper mold pressure on the gypsum model with a difference Druσkraum is connected.

6. Apparatus according to claim 5, dadurchge ¬ indicates that at the at least one opening (6) of the base plate (5) in the atmosphere outside of the cuvette (2) aufneh¬ ing polymerization vessel (1) leading line (8) is connected ,

7. Apparatus according to claim 6, dadurchge ¬ indicates that the Differenzdruck¬ space arranged in the form of at least one recess (25) in the base plate (5) and this with the minde¬ least one opening (6) and at this Öff¬ opening (6) a suction connection channel (23 ') is connected.

8. Apparatus according to claim 5, dadurchge - indicates that a occlusion stabilizer (12) is arranged detachably and fixably on the baseplate (5) or on the upper part of the cuvette (16).

9. Device according to one of claims 5 to 8, ¬ characterized in that on the base plate (5) within the cuvette (2) around the gypsum model (3) up to the level of Modellieran¬ set (28) has a Heißpolymerisationstemperatur-resi- stente sealant (29) is arranged (Fig. 7).

10. The device according to one of claims 5 to 9 for the production of dental prostheses or prosthesis parts of polymerizable plastic, consisting of a cuvette with base plate and the auszuschießenden cavity limiting gypsum model and upper mold, wherein in the base plate of the upper mold and arranged on the base plate gypsum model At least one opening in the gypsum model setting area is arranged in the cuvette and this opening is connected to a differential pressure gray for maintaining a lower pressure on the plaster model with respect to the pressure at the mold top, characterized in that in the cuvette (2 ) arranged upper part (4) at least in the Be¬ rich of the pouring opening (35) of the Kunststoffeinfüll¬ funnel (18) at least one circumferential Abdich¬ tungsschikane (36), as from the material of the Form¬ upper part (4) shaped sealing lip, is arranged.

11. A process for the production of dental prostheses or prosthesis parts from polymerisable plastic, wherein the plastic in one of the prosthesis form correspond to the one, on the one hand by the plaster model and on the other hand by a tooth set up and the free-lance The cavity bounded by the plaster model as a whole enclosing the mold cavity is introduced into a polymerization vessel in a vial containing the plaster model and the upper mold part, characterized in that the pourable plastic is introduced into a centric cavity of the prosthesis model and from there poured uniformly from bottom to top in the vertically held model cavity and filled the central cavity at least up to the height of the model cavity and this is kept under pressure during the polymerization.

12. The method of claim 11, wherein a lower pressure than in the model cavity is maintained via at least one open location on the base bottom side of the plaster model at the latest during the polymerization.

13. Prosthesis production mold for carrying out the method according to claim 11 or 12, consisting of the cuvette arranged in a cuvette, the aus¬ zugießenden prosthesis cavity enclosing mold with Kunststoffingießkanälen, characterized in that in Modelllober¬ or -untererteil (50, 51 ), a pouring container (52) is centrally connected to the mold, several channels (53) of which are guided to the model cavity (54), and the pouring container (52), which is pressure-tightly closable by means of a lid (56), is provided with devices (52). 55) for generating internal pressure in Ein¬ pouring container (3) is provided.

14. Mold according to claim 13, dadurchge - indicates that the device (55) is designed to generate the internal pressure in the form of a displacement piston (58 ') guided on the cover (56).

15. A mold as claimed in claim 13, wherein a means for generating the internal pressure is in the form of a cap

(56) fixed elongated bladder (59) is formed and this with an expansion-limiting grid (59 ') is surrounded.

16. A mold according to claim 13, dadurchgekenn ¬ characterized in that the Eingießbehälter (52) adapted in shape to the parabolic course of Zahnstel¬ ment and at its directed against the tooth position flanks (70) with at least one Ka¬ the channels (53) forming Slot (71) is provided (Fig. 7).

17. A pressure polymerization vessel for the prosthesis preparation form according to one of claims 13 to 16, consisting of a heatable pressure-sealable pressure-sealable pressure cup, in the upper region on the cover (72) or the pot wall (74) of the pressure pot

(75) at least one more pressure line handle

(76) is arranged (Fig. 7).