WO1987005800A2

WO1987005800A2 - Polymerizable mass for production of non-hardening moulded elements, particular of dental prostheses

Info

Publication number: WO1987005800A2
Application number: PCT/DE1987/000135
Authority: WO
Inventors: Wolfgang Heynold; Siegfried Reiss
Original assignee: Wolfgang Heynold; Siegfried Reiss
Priority date: 1986-03-29
Filing date: 1987-03-27
Publication date: 1987-10-08
Also published as: DE3610683A1; WO1987005800A3

Abstract

The polymerizable mass is intended for the production of non-hardening moulded elements, in particular of dental prostheses and consists of a mixture of: (a) urethane oligomers with one or several polymerization-inducing acrylate and/or methacrylate groups; (b) one or several C1-C14-alkylacrylates, -methacrylates, -bi- or -tri(meth)acrylates; (c) polymerization-inducing components selected from the group of benzyl ketals, ketoxine esters, benzophenones, camphor quinones, in particular acetophenone derivatives and acyl phosphine oxide compounds, whereby the components (a) and (b) are contained in the mass in such a ratio that the latter has a Shore hardness of 20 to 80, preferably 40 to 60 and a minimum breaking strength of 0.3 N/m2 in the polymerized state. This mass is processed in such a manner that the flexible remaining moulded elements are produced separately and are inserted, in the polymerized final shape, in the cavity for the manufacture of the entire prosthesis and the remaining cavity on the prosthesis positioning side is filled with the hard-polymerizing plastic and polymerized.

Description

Polymerizable composition for the production of soft molded parts, in particular dentures

The invention relates to a polymerizable composition for the production of soft molded parts of denture parts in particular and also relates to a method for producing such prostheses using the composition according to the invention and finally to a mold and an apparatus for performing the method.

Dental prostheses made of plastic are known and basically manufactured in such a way that the plastic forming the prosthesis is introduced into a cavity shaped according to the impression, which also contains the tooth position, plastic and the polymer is polymerized out. For this purpose, a wide variety of polymerizable plastic compositions are used and, depending on the type of plastic, appropriate polymerization processes are used which are generally known and so far require no further explanation and lead to more or less well-fitting prostheses. Since the actual prosthesis body, which sits on the jaw and bears the artificial teeth, is relatively hard and, in addition, changes can occur in the jaw during the wearing time of the prosthesis, which can also be caused in part by wearing the prostheses, particularly on the jaw side, with respect to the rest of the prosthesis body softer to create a kind of cushion. So far, silicone suitimi has been used for such soft cushions, which brings the desired cushioning effect. The production of such prostheses is rather cumbersome and it has also been found that the connection between the silicone rubber and the base of the prosthesis body leaves something to be desired, ie, after a relatively short period of wear, the silicone rubber detaches from the prosthesis body. The use of plastics based on methyl methacrylate for the prosthesis padding, which remain soft due to the addition of plasticizers, has also proven to be disadvantageous. With such prostheses, embrittlement occurs immediately, which can be attributed to the fact that the plasticizer migrates, with further complications that plasticizers are known to be good breeding grounds for bacterial formation, so that odor nuisance very often results from such prostheses. Furthermore, plastic mixtures that remain soft (exact composition unknown) without plasticizers are known, which, although less prone to embrittlement, but practice has shown, such prostheses are also extremely bacteria-friendly and also immediately lead to unpleasant odors.

The invention is therefore based on the object to provide a polymerizable mass for the production of soft molded parts, in particular dental prostheses, which do not have the disadvantages mentioned, well as pourable and, if necessary, also pasty as moldable or directly applicable to a model in some areas Have the manufacture of such special prostheses processed, which are hygienically perfect and which form a firm connection with the actual prosthesis body, so that there is no fear of detachment.

This object is achieved with a polymerizable composition according to the invention by the features stated in the characterizing part of the main claim. Advantageous further developments and practical embodiments with regard to the mass result from the subordinate claims directed thereon.

The mass according to the invention can also be used for the production of so-called gum epitheses, especially since the same mass can be used here by appropriate hardness adjustment, on the one hand to form the surface shell which is labially harder on the face side, while the mass set according to the invention is used on the tooth side, which is then suitable according to the impression molded nubs with which the epithesis can be locked in the interdental areas. Since the mass according to the invention has very good hygienic properties, it is also, for example, for producing otoplastic parts, for example, but also for medical hose lines and the like. Like. Suitable. The proviso that. components a) and b) should be present in the mixture in a ratio such that shore hardnesses of 20 to 80 are obtained ben and a tensile strength of at least 0.3 is due to the fact that these components a) and b) can be brought together in different mixing ratios, ie different oligomers of component a) can be mixed together with the different types of component b) for which, however, according to exemplary embodiments still to be explained, in each case different mixing ratios are to be observed. However, it is always essential that the upper and lower permissible limit values for the Shore hardness are observed for the present purpose and that a lower limit of the tensile strength is observed. Determining this is not a problem and can easily be determined using appropriate test series. It is therefore essential to the invention that the components according to a) and b) are mixed for the preparation of the composition, and a component according to c) which is effective for polymerization is also added, which depends on the type of polymerization to be used. For reasons of process engineering, the use of components which have an effect on light polymerization is preferred, which will be explained in more detail below. In addition to the fact that the composition according to the invention has proven to be hygienically perfect, bactericidal additives can be added to it without further ado.

For the processing of this composition according to the invention for the production of prostheses with soft molded parts, a mold cavity corresponding to the impression must of course also be used, as mentioned above, into which the composition and also that for the actual prosthesis body must be introduced and then polymerized. In this case, however, the procedure according to the invention is such that the molded part that remains soft and elastic is manufactured separately and introduced into the cavity for the manufacture of the entire prosthesis in a polymerized final form and the tooth cavity on the tooth position side is filled with the hard polymerizing plastic and polymerized. However, this process, which appears to be complicated, is, as will be explained in more detail, very simply to be carried out, especially since this gives the possibility of effecting the polymerisation of the soft-elastic molded part preferably by light polymerisation. This invention In any case, the method is easier to carry out than the method that has been used to date to form prostheses with a soft molded part made of silicone rubber on the jaw side. Since, as mentioned above, the light polymerization of the soft-elastic molded part is preferred, the manufacturing process for the prosthesis is advantageously carried out in such a way that transparent duplicating material is used for the second molded upper part to be molded onto the removed wax model and light-polymerizable plastic is used for the remaining soft-elastic prosthesis part and this is light-polymerized with the transparent top attached. As has been shown, the composition according to the invention is almost fully polymerized during light polymerization, so that the residual monomer content is advantageously below 0.5%.

In order to achieve an optimal fit accuracy of the prosthesis, the procedure is advantageously carried out in such a way that both the molding and solidification of the duplicating material for both upper mold parts and the polymerization of the plastics which remain soft and elastic and the hard polymerizing plastics take place while maintaining a differential pressure between the upper and lower mold parts, that there is less pressure on the lower part than on the upper part. This measure is known in principle according to DE-PS 34 40 205, but in the present case it ensures in particular that the duplicating compound and also the plastics lie optimally on the lower part of the mold. The shape or the cuvette that is used for the method according to the invention essentially corresponds to previous cuvette shapes, such as are used for the aforementioned method according to DE-PS, but in this form alone, however, not for the implementation of the method using light polymerization is sufficient. For this purpose, the shape must consist of a further cuvette upper part which can also be connected to the lower part of the cuvette and which is designed as a frame which keeps the entire cross-section of the cuvette free and which corresponds to the receiving contour of the lower part of the cuvette.

Likewise, the device for carrying out the method by means of the above-mentioned special form requires special training, starting from a pressure-tight seal and with Pressurizable container with a connection for the lower mold part connected to the atmosphere, in that at least one polymerization-effective light source is arranged in the interior of the container.

The method according to the invention for processing the mass according to the invention in conjunction with the associated cuvette and the device for carrying out the method is explained in more detail below with the aid of exemplary embodiments.

It shows highly schematic

Fig. 1 the process diagram for the manufacture of a mandibular prosthesis;

2 shows the process diagram for the manufacture of an upper jaw prosthesis;

Fig. 3 the cuvette for carrying out the method;

Fig. 4 the device for light polymerization and

Fig. 5 shows the device for the polymerization of the entire prosthesis.

Since the anatomical conditions on the upper jaw are different from those on the lower jaw, there are somewhat different procedural steps for processing the special mass mixture to form soft-elastic molded parts on prostheses, taking into account that total cushioning of the contact surface is desired for a lower jaw prosthesis , on the other hand, this is not indicated for a maxillary prosthesis, but only there in the area of the gum flap edge of the prosthesis body.

First of all, reference is made to FIG. 1, in which half a cuvette part is always shown only in a highly schematic manner. In the sense of the arrows indicated, starting from the top left, proceed as follows: W is the wax model and Z the tooth position. As usual, the cuvette top 1 is poured out with duplicating compound, which forms the top 3 after solidification, which is then removed as a whole with the cuvette top 1. The wax model W is now, as shown to the right of it, removed to the thickness that the soft cushion part is to receive. This residual wax model is designated W '. A new upper part 6 of the cell, which has the shape of a frame 6 'which keeps the overall cross section of the cell, is now placed on this prepared lower part 2 of the cell. In this attached frame 6 ', now, since light polymerization is used, transparent duplicating material is molded by simply pouring this material into the open frame. After the transparent duplicating material has solidified, this cuvette upper part 6 with the molded upper part 3 'contained therein made of transparent duplicating material is removed and the residual wax model W' is removed. Then the cuvette upper part 6 (bottom left in FIG. 1) is put back on and after piercing the pouring channels, the soft-elastically polymerizing mass is poured into one of the pouring channels and until the mass rises in the other pouring channel. In this state, the cuvette is inserted into a container according to FIG. 4, which is provided with a light source 12 which emits light effective for polymerization (for example UV radiation). After a corresponding polymerization time (10 to 15 minutes depending on the setting of the mass), the cuvette is removed again and the top part of the cuvette with the transparent doubling gel, through which the light polymerization was carried out, is removed. After removal of the channel castings, the cuvette upper part 1 with its molded upper part 3, which is also made of duplicating material, is put back on again (see bottom right in FIG. 1) and now the plastic K, which forms the actual prosthesis body, and the tooth position, is placed in the remaining cavity Includes Z, filled with appropriate pouring channels and with the whole cuvette in the vertical position, vertically adjusted in a container according to FIG. 5 and polymerized under pressure and heat, depending on the type of plastic K. If one uses plastic K which can be light polymerized, the light polymerization method can of course be used for this final polymerization through a transparent upper mold part 3 can also be used, regardless of whether, as mentioned above, a soft cushion part is already present in the mold cavity or not.

If there is no soft upholstery part, it is of course not necessary to replace the cuvette upper parts, which contain the duplicating material.

2 is the process steps for the manufacture of a maxillary prosthesis, only half of the cuvette part being shown here as well. It is also important here to replace the cuvette upper parts 1 and 6, but removal of the wax model W, as described above, is not absolutely necessary, since only the area of the so-called gum envelope edge is to be grasped here and designed as a soft cushion part. Here, in phase B with the remaining wax model W, the transparent duplicating material is filled into the frame 6 '(hatched), but only up to a height as indicated, i.e. up to the upper limit of the area forming the gum envelope edge. When the doubling gel has solidified, the upper part is raised. The solidification can be accelerated, for example, by inserting the cuvette horizontally, as shown, into a container according to FIG. 4, which is equipped on the bottom with a heat exchanger 13 in the form of a cooling coil through which the water in the container 11 is heated can be withdrawn. The same also applies to the previously described method according to FIG. 1

After lifting off the upper part, the entire wax model W is now removed in phase B, so that the soft-elastically polymerizing plastic mass WE can now be introduced into the groove between the lower mold part 4 made of plaster and the "molded upper part" 3 'made of transparent duplicating material. If desired, as indicated, the exposed surface of the lower mold part 4 made of plaster can also be applied with a thin layer WE 'of the same soft-elastic polymerizing material (phase C). In this state, the cuvette is placed in the container 11 4 and exposed to the whole of the polymerizing radiation emitted by the emitter 12 for a sufficiently long time to polymerize the mass WE and the thin layer WE '. Thereafter, the frame-like cuvette upper part 6 is replaced again with the cuvette upper part 1 provided (phase D), so that after the appropriate pouring channels (see phase E), the hard-polymerizable plastic K is introduced into the vertical position of the cuvette and the whole is then placed in a container 15 as shown in FIG. 5 can be polymerized.

As mentioned above, in both cases it is advantageously carried out in such a way that both the molding and solidification of the duplicating material for the second upper mold part 6 and the polymerization of the mass which remains flexible and the hard polymerizing plastic K take place while maintaining a differential pressure between the upper and lower parts of the mold that there is less pressure on the lower part than on the upper part. For this purpose, the cuvette lower part is designed in the sense of DE-PS 34 40 205, i.e. in such a way that a lower pressure is established on the lower mold part 4 than on the upper mold part 3 or 3 '.

Since the final polymerization is to be carried out advantageously under pressure in both cases in order to optimize the connection between the soft-elastically polymerized upholstery part made of the mass WE and the hard polymerizing plastic K and to counter the inevitable shrinkage of the plastic K, the cuvette upper part 1 is shown in FIG. 3 advantageously designed in such a way that a closable filler neck 8 is interchangeably arranged in the at least one filling opening 5 and that a differential pressure piston device 9 is also releasably provided on the cuvette, the piston 10 of which having the larger area is located outside the cuvette. Depending on the design and dimensioning of the differential pressure piston device 9, after the mold cavity has been filled, it can also be used directly anchored in the filler neck 8. An arrangement in an opening 5 'additionally provided for this purpose on the upper cuvette part 1 is also possible. The function of this training 3, in which filler neck 8 and differential pressure piston device 9 are arranged next to one another. Since the plastic K is filled up to just above the upper edge of the filler neck 8, the plastic K is pushed up by a push-in and lockable sealing plug 8 'in the channel 9', which is closed by the small piston 10 ', whereby below the large-area piston 10 in the differential pressure piston device 9 a certain vacuum is created. As soon as the cuvette 16 is under pressure in the container 15, it acts on the large-area piston 10 and presses it down, as a result of which the plastic in the cavity is under pressure. This arrangement has proven to be expedient and effective in so far as simply allowing the pressure in the container 15 to act directly on the plastic K in a correspondingly large filling funnel T.

Regarding the special mixture of masses for the soft-elastic upholstery molding, which can advantageously be processed in the manner described to form a correspondingly padded prosthesis, some examples of possible mixture compositions with sufficient Shore hardness are given below for the present purpose.

Exemplary embodiments for mass mixtures in the form of test specimens

In all of the exemplary embodiments, test specimens in disk form with a thickness of 30 mm and 5 mm were produced from the mass mixtures in question using light polymerization (about 15 minutes) and the hardness was measured on them. The tensile strength (RF) was measured according to DIN 53 504 at 21 ° C on appropriate test specimens.

Example 1 (MMA = methyl methacrylate)

Components weight percent a)% urethane 88 78 68 58 b)% MMA 10 20 30 40 c)% pol. Comp. 2 2 2 2

Shore A (20 ² C) 54 52 58 80

RF 0.86 1.80 3.22 5.75 Example 2 (EMA = ethyl methacrylate)

Components weight percent a)% urethane 78 68 58 48 b) EMA 20 30 40 50 c)% pol. Comp 2 2 2 2

Shore A (20 ° C) 50 48 47 47 RF 1.03 1.13 1.79 1.86

Example 3 (I-BMA = iso-butyl methacrylate)

Components weight percent a)% urethane 88 78 68 58 b) I-BMA 10 20 30 40 c)% pol. Comp. 2 2 2 2

Shore A (20 ° C) 50 47 42 39 RF 0.75 0.98 0.97 0.92

Example 4 (n-HMA = n-hexyl methacrylate)

Components weight percent a)% urethane 88 78 68 58 b)% n-HMA 10 20 30 40 c)% pol. Comp. 2 2 2 2

Shore A (20 ° C) 52 43 42 36 RF 0.76 0.60 0.39 0.35

As far as the manufacture of the aforementioned gum epitheses is concerned, one or the other method is used, depending on their shape, but instead of the plastic K, the same mass is used as for the tooth-side cushioning and latching area, but the hardness is higher is set in order to make the face-side shell of the epithesis more dimensionally stable.

If only partial areas are to be present on a prosthesis as soft cushion parts, these partial areas can be made on the plaster model (form lower part) can be achieved by direct application of paste-like compositions, in which case the plaster model with the applied partial mass areas is exposed to polymerizing light and, after polymerisation, the molded upper part 1 is placed, the plastic K is poured in and the whole is polymerized with respect to the plastic K. In this regard, reference is made to phase E in FIG. 2, which of course also applies to a lower jaw prosthesis in this case. The finely hatched part then only represents a partial application of paste-like mass and, if provided, the dashed layer application does not have to extend over the entire model area.

There are now two practical examples of pourable and spreadable, soft polymerizing materials:

Embodiment 5 for a pourable plastic mass:

Composition for a total batch of 5.1 kg

3,000 g urethane oligomer (difunctional) with a molecular weight of 5,000

1,500 g of ethyl methacrylate

500 g methyl methacrylate

100 g UV initiator (acetophenone derivative)

The methyl and ethyl methacrylate are introduced into a 10 liter vessel and then the urethane oligomer is added with stirring. This mixture is stirred until the mixture is homogeneous. In the absence of light, the correspondingly weighed amount of UV initiator is then also added while stirring continuously. The whole thing is done at normal temperature. The homogeneous mixture is then filled into light-tight consumer containers (e.g. bottles).

Example 6 for paintable plastic compound:

Composition for a total batch of 1.08 kg

400 g of ethyl methacrylate

600 g urethane oligomer (difunctional) with a molecular weight of 5,000

20 g UV initiator (acetophen derivative) 60 g suitable thickener These components are mixed together under the same conditions as in embodiment 5 in a correspondingly smaller vessel, the thickener finally being added with rapid stirring and likewise being distributed homogeneously. This homogeneous mass is then also filled into light-tight consumer containers in the form of tubes, which expediently have a pointed mouthpiece, so that the mass can be applied directly to desired sub-areas of the model, as described above, using this tube, if necessary. Silicon dioxide was used as the thickener.

Claims

Claims:

1. Polymerizable composition for the production of moldings which remain soft, in particular dental prostheses, based on a urethane oligomer with one or more polymerization-active groups and polymerization-active additives, so that it consists of a mixture of

(a) urethane oligomers with one or more polymerization-effective acrylate and / or methacrylate groups,

(b) one or more C ₁ -C ₁₄ alkyl acrylates, methacrylates, bi- or tri (meth) acrylates,

(c) polymerization-active components selected from the group of benzil ketals, ketoxime esters, benzophenones, camphor quinones, in particular acetophenone derivatives and acylphosphine oxide compounds, the components (a) and (b) being in such a ratio in the

Mass are included that this has a Shore hardness of 20 to 80, preferably 40 to 60 and a minimum tensile strength of 0.3 N / m ² in the polymerized state.

2. Composition according to claim 1, d a d u r c h g e k e n n z e i c hn e t that the mass is formed by a share of about 5 - 8% of thickeners, such as thickeners based on silicon dioxide as a spreadable, pasty mass.

3. Composition according to claim 1, dadurchgekennzeic hn et that bactericidal and / or biocidal additives, such as chlorhexidine, riboflavins, additives based on H ₂ O ₂ or the like are contained in the mixture.

4. A process for the production of prostheses with soft molded parts using the mass according to claim 1, wherein the polymerized mass is introduced into a divisible, consisting of upper and lower part hollow prosthesis and polymerized in this, characterized in that the soft-elastic molded part from the mass (WE) manufactured separately and in auspolymerisier The final shape is introduced into the cavity for the production of the entire prosthesis and the tooth cavity on the tooth position side is filled with the hard polymerizing plastic (K) and polymerized.

5. A process for the production of prostheses with soft molded parts, which cover only limited areas of the prosthesis, using the composition according to claim 2, characterized in that the soft polymerizing mass (WE) is applied to the lower part of the mold by brushing and polymerized .

6. The method of claim 4, d a d u r c h g e k e n n z e i c h n e t that the hard polymerizing plastic (K) is polymerized out under pressure.

7. The method according to claim 4 or 6, characterized in that a) the wax model (W) corresponding to the final shape of the prosthesis, which is seated on the lower mold part, is removed with the first upper mold part removed except for the part of the final prosthesis which is to remain soft, b) on the lower mold part with the removed one A new, second upper part of the mold is molded on from the duplicating material, the removed wax model is removed, the mass (WE) forming the soft-elastic prosthetic part is inserted and polymerized in the cavity between the lower part of the form and the second part of the upper part, and polymerized, c) the second upper part is replaced by the first upper part and inserted into the remaining remaining cavity of the plastic (K) forming the hard prosthesis part is introduced and polymerized.

8. The method according to claim 7, characterized in that for the second, to be molded onto the worn wax model, transparent duplicating material and for the soft-elastic prosthesis part Light-polymerizable plastic is used and this is light-polymerized with the transparent top attached.

9. The method according to claim 4 or 6, for the production of

Upper jaw prostheses, characterized in that a) with the first upper part removed, a second upper part, which only delimits the gum envelope edge, is molded on, the wax model (W) is removed, the remaining, open cavity for the gingival edge in the second upper part with the soft-elastically polymerizing mass (WE) filled and this is polymerized and b) the second upper mold part is exchanged for the first upper mold part and the plastic (K) forming the hard prosthesis part is introduced into the remaining remaining cavity and polymerized.

10. The method according to claim 9, d a d u r c h g e k e n n z e i c h n e t that when the open cavity is filled, the surface of the mold part corresponding to the palate surface is covered with a thin layer of the soft-elastic polymerizing plastic.

11. The method according to any one of claims 4 and 6 to 10, characterized in that both the molding and solidification of the duplicating material for the second upper mold part and the polymerizations of the soft-elastic and hard polymerizing plastic while maintaining a differential pressure between the upper mold and - take place in such a way that a lower pressure is maintained on the lower part than on the upper part.

12. Cuvette for performing the method according to one of claims 4 to 11, consisting of a cuvette upper and a cuvette lower part (1, 2) for receiving the model form upper and lower parts (3, 4), wherein in the cuvette upper part (1) at least A lateral filling opening (5) is arranged, characterized in that the cuvette is formed from a further cuvette upper part (6), which can also be connected to the cuvette lower part (2), and this is designed as a frame (6 ') which keeps the entire cuvette cross-section free and which accommodates the receiving contour ( 7) corresponds to the lower part of the cuvette (2).

13. A cuvette according to claim 12, that a closable filler neck (8) is interchangeably arranged in the at least one fill opening (5).

14. Cuvette according to claim 12 or. 13, so that a differential pressure piston device (9) and the piston (10) with the larger area outside the cuvette are detachably arranged on the cuvette.

15. An apparatus for performing the method according to claim 9 for light polymerization, consisting of a pressure-tight sealable and pressurizable container with a connection to the atmosphere for the lower mold part, characterized in that in the interior of the container (11) at least one effective polymerization Light source (12) is arranged.

16. An apparatus for performing the method according to claim 11 for the solidification of the duplicating mass in the second cuvette top part according to claim 12, consisting of a pressure-tight sealable and pressurizable container with a connection to the atmosphere for the bottom part, characterized in that in the area a heat exchanger (13) for the passage of a cooling medium is arranged on the tank bottom.

17. Apparatus according to claim 15 and 16 for performing the method according to claims 3 to 10, characterized in that the light source (12) and the heat rope shear (13) are arranged together in a container (11) and the container is provided with a cuvette differential pressure connection (14).