EP3463177A1

EP3463177A1 - Ceramic shell for producing a dental prosthesis and method for producing a ceramic shell for a dental prosthesis

Info

Publication number: EP3463177A1
Application number: EP17725261.6A
Authority: EP
Inventors: Joachim Meyer
Original assignee: Bredent GmbH and Co KG
Current assignee: Bredent GmbH and Co KG
Priority date: 2016-05-23
Filing date: 2017-05-23
Publication date: 2019-04-10
Also published as: WO2017202867A1; US20190209275A1; DE102016109447A1

Abstract

The invention relates to a ceramic shell (10) for producing a dental prosthesis and to a method for producing a ceramic shell for a dental prosthesis, particularly for veneering a dental scaffold (11) or as a full ceramic dental prosthesis, wherein the ceramic shell (10) is manufactured in the form of a green compact from a ceramic powder and a binder system such that said ceramic shell can be shaped flexibly and can be adjusted plastically to adapt to a body.

Description

Ceramic shell for the production of dental prostheses and method for producing a ceramic shell for dentures.

The invention relates to a ceramic shell for the production of dental prostheses and a method for producing a ceramic shell for dental prostheses, in particular for veneering a dental framework or as a full ceramic dentures.

The use of ceramic materials is widely used in dental technology. In addition to use in prosthetics, such as. As for single crowns, for example, veneers (so-called. Veneers) made of ceramic.

WO 2007/028 787 A1 discloses ceramic dentures and a method for the production thereof. In this document dentures, in particular in the form of a composite crown or a composite bridge is described, which consists of two independent components, which are formed as an inner framework structure and outer veneer, which by a

Connector ground are connected together. The Konnektormasse is liquid at room temperature or at least viscous to simplify the processing.

From DE 600 23 315 T2 a method for producing a functional dental element is known in which layers of a suitable ceramic material, which is a powder, are applied successively. In doing so, a binder is applied to each layer of powder at desired positions by means of a three-dimensional printing technique to bond each layer of powder to the previous layer, thereby allowing the removal of excess, non-adherent powder. Subsequently, the dental element thus formed is subjected to a sintering step and the sintered Element is infiltrated by a second phase. The sintering step may also be followed by a delivery step.

DE 10 2009 051 593 A1 discloses a bonding agent between an oxide ceramic and a veneering material, in particular for dental purposes. In this case, a primer in the form of a mixture of silicate ceramics and quartz is applied as a sol to be veneered and not yet dense sintered body of oxide ceramics or their starting materials. Subsequently, the base body is finally sintered with the knitted bonding agent and then the veneering material is applied. As a result, high-strength dental crowns or bridges can be produced.

In US 2004/0245663 A1 a green ceramic tape is described, which can be used for the production of dentures. The tape is placed around a model of a tooth stump for this purpose and then adapted and fired.

From US Pat. No. 5,346,397 A, a method for the production of dental prostheses is known, in which a not yet adapted and unfired ceramic shell is used together with a ceramic paste as a building material, so that a color-matched and shape-matched but still unfired dental prosthesis is produced.

EP 0 826 642 A2 describes the production of a ceramic dental prosthesis crown or a ceramic denture shell in which a slurry is formed into a thin layer, this thin layer is placed on a plaster mold, dried layer by layer and after application of all required layers the blank is sintered. "

The object of the invention is to provide a ceramic shell in anatomical form for the production of dental prostheses or to provide a method for producing a ceramic shell for dental prostheses, which allow a simple processing of the ceramic shell.

This object is solved by the features of independent claims 1 and 11. Further advantageous embodiments of the invention are each the subject of the dependent claims. These can be combined in a technologically meaningful way with each other. The description, in particular in conjunction with the drawing, additionally characterizes and specifies the invention.

According to the invention, an anatomically preformed ceramic shell for the production of dental prostheses, in particular for veneering a dental device or as a full ceramic dentures specified, which is made as a green compact of a ceramic powder and a binder system and the ceramic shell on a body as a whole without loss of the characteristic anatomical shape is anaptable, especially in border areas. Starting point is a customary dental ceramics, such. Example, an oxide, silicate or glass ceramic and other technical ceramics, which are adapted in terms of their thermal expansion coefficient to the appropriate application. The ceramics to be used are produced by powder metallurgy from a suitable glass frit and ground and treated with a corresponding binder system in a stirrer to a slurry pasty. A special feature of the ceramic shell according to the invention is therefore the dosage form as Schlickerkeramik, so that a flexible ceramic is provided, which can be adapted plastically shaping prior to firing. Thus, it is possible the shape curve at the preparation border .

individually adapted by bending and cutting, which significantly simplifies the processing. Accordingly, in the case of the ceramic shell according to the invention, the shaping process for forming the anatomical shape has already been completed, resulting not only in time or cost savings, but in particular improved reproducibility and easier integration into a treatment procedure. The ceramic shell is anadaptierbar without loss of anatomical shape to a support or a framework, so that minor adjustments are still possible even after shaping. The term "characteristic anatomical shape" is understood here to mean that the ceramic shell already has the final shape, apart from the shrinkage that normally occurs during the sintering process

Sintering shrinkage can be taken into account in the manufacture of the ceramic shell by means of a suitable method, which however does not form part of the present invention. It should be noted in particular that the sintering shrinkage does not have to be linear with respect to the three spatial axes in all cases.

According to one embodiment of the invention, the green compact is monochrome or polychrome.

Accordingly, it is possible to form plastically deformable monochrome or polychrome ceramic veneers, which are present as unfired shaped body. In the case of polychrome ceramic shells, it is possible to adapt the color of the dental prosthesis to be formed, for example, in the dentin area.

According to a further embodiment of the invention, the green compact can be connected to the dental framework or a refractory molded body by means of a viscous ceramic filling compound, in particular a ceramic sol. The flexible ceramic shell is back-injected after shaping adaptation to the veneer framework or another dimensionally stable molded body with a viscous ceramic filling compound. The filling compound can be provided as a ceramic sol with high viscosity. By pressing on the veneer or the refractory form body excess filler is pushed out, so that any voids or air pockets are filled. The ceramic filling compound serves as a balancing mass z. B. undercuts or to compensate for different gaps between the ceramic shell and the framework. The filling material functions here functionally to compensate undercuts and different gap mass, as they would cause unwanted sink marks on the anatomically shaped vestibular area.

According to a further embodiment of the invention, the viscous ceramic filling compound is accompanied by UV initiators for light polymerization.

This makes it possible to fix the adapted in the form of flexible ceramic shell to the first firing in the correct position on a support or scaffold.

According to a further embodiment of the invention, the ceramic filling compound has thixotropic properties.

It can be z. For example, a conventional powder-ceramic-water mixture can be applied with a brush or a corresponding ceramic sol with thixotropic properties can be provided.

According to a further embodiment of the invention, the viscous ceramic filling material causes a color matching. Accordingly, there is the additional possibility with a tooth-colored, chromatic coloring to make a subsequent natural color adjustments of the ceramic shell and its basic color.

According to a further embodiment of the invention, the ceramic shell has a tooth-coloring property.

The ceramic shell is here not only formed as a thin shell, as was already known in the prior art, but represents a significant Antel of the veneer, so that a tooth color on the ceramic shell can be fixed.

According to the invention, a method for producing a ceramic shell for dental prostheses, in particular for veneering a dental framework or as a full ceramic denture, which comprises the following steps, is also specified. After providing a Keramikschiickers takes the forms of Keramikschiickers to a slurry film, as well as a possible pre-drying of the slip film to adjust the degree of moisture and thus the required viscosity. After pressing the slurry film, for example, in a film form as a negative mold to form a concave flexible ceramic shell follows a removal of the flexible ceramic shell in the form of a green body. The shaping of the ceramic sheeting can be carried out in such a way that two adjacent or superimposed slip films are formed, which have different colors or transparency, so that the resulting slurry film has monochrome or polychrome properties. The molding process of the ceramic joiner is based on different way possible. For example, the Keramikschiicker can be produced by injection molding or embossing, but it is also possible to apply the Keramikschiickers on a structured carrier film or silicone mold. It is also possible to use mixed forms from the shaping processes in order to shape the ceramic foamer accordingly.

The wet slurry film may pass through a drying zone to adjust the moisture level so that the slurry film becomes pasty and easily moldable. The slurry film can be created on the basis of the degree of moisture with the viscosity which is adapted to the desired further processing and application. Preferably, by means of a downstream structural roller of the slurry can be pressed into the forming embossed film as a negative mold to achieve a slightly concave tooth-shell shape of the ceramic shell. Typical layer thicknesses are 0.1 to 2 mm, wherein, as already mentioned above, different ceramic materials can be used with a suitable binder system.

Some embodiments will be explained in more detail with reference to the drawing. Show it:

Fig. 1 shows an arrangement for producing an inventive

Ceramic bowl in a side view;

FIG. 2 shows the arrangement of FIG. 1 in a plan view; FIG. Fig. 3 shows a ceramic shell according to the invention together with a

Verblendgerüst; and 4 shows a ceramic shell according to the invention together with a

Moldings.

In the figures, identical or functionally identical components are provided with the same reference numerals.

With reference to FIG. 1, an arrangement 1 is described below, with which ceramic shells according to the invention can be produced. From a first Schlickertrichter 2 and a second Schlickertrichter 3 a suitable ceramic is applied with a binder system as aqueous or pasty Schlicker on slot dies on a structured carrier film 4 as a negative mold. The two Schlickertrichter 2 and 3 are filled with differently colored Keramikschiicker, which can cause, for example, in the enamel and Dentinbereich for a different color.

The application of the two Keramikschiicker can be performed simultaneously next to each other or behind each other. Thus, two ceramic dyeings are formed, which run into each other. The slurry film can pass through a drying zone to adjust the moisture level so that the slurry film becomes pasty and easily moldable. By means of a downstream structure roller 5, the slurry can be pressed into the forming embossed film 4. The film 4 may be applied to an all-around conveyor belt 6. The processing of Keramikschiickers ceramic shells with the arrangement 1 of FIG. 1 will be explained in more detail below with reference to FIG. 2. FIG. 2 shows a plan view of the structured carrier foil 4 in the area of the slip funnels 2 and 3 and of the structure roller 5. It can be seen that the carrier foil 4 has, for example, an embossed labial surface of front teeth has as a structure, which are provided in Fig. 2 by the reference numeral 7.

The Schlickertrichter 2 and 3 are a first Keramiksehl icker 8 and a second Keramikschiicker 9 from which, as shown in Fig. 2, are arranged side by side. In the region of the structure roller 5, the two ceramic slip 8 and 9 are formed into a slurry film, which forms the concave flexible ceramic shell 10 by being pressed into the film shape. In this case, the ceramic foamer 8 or 9 can also be applied by means of injection molding or embossing or can be converted into injection or injection-compression molding as a shaping process by means of a ceramic sprinkler.

In other variants of the method according to the invention, the concave flexible ceramic shell 10 could also be produced by means of deep-drawing or by introduction into mold plates designed as foils.

The use of the flexible ceramic shell 10 will be explained in more detail below with reference to FIG. In Fig. 3, a veneer framework 1 1 is shown schematically, which has a corresponding convex facing surface 12. On this convex veneer surface 12, the anatomically preformed ceramic shell 10 is placed. The ceramic shell 10 has a concave contact surface 13, wherein a gap 14 is present between the concave contact surface 13 and the convex veneering surface 12. The opposite side of the ceramic shell 10 represents the vestibular, anatomical tooth shape 15. The gap 14 between the convex veneer surface 12 of the veneer frame 1 1 and the concave contact surface 13 of the ceramic shell 10 is provided by means of a ceramic filler, which is typically provided as a ceramic sol , eliminated. The opposite contact surfaces The gap 14 between the concave contact surface 13 of the ceramic shell 10 and the convex veneer surface of the framework 11 is provided by means of a ceramic filling compound, which is typically provided as a ceramic sol. miniert. In this case, the viscous ceramic filling material acts as a balancing mass, and can compensate for different gap dimensions and undercuts between the ceramic shell 10 and the veneer frame 1 1 accordingly.

The ceramic filling compound i. the ceramic / glass sol is here to compensate for unequal gap dimensions or undercuts of the framework or of the molded body as a refractory mass, in order to avoid the resulting sink marks on the ceramic shell 10 and the anatomical outer surface 15. For this purpose, the ceramic shell 10 is back-injected after a shaping adaptation to the veneer frame 1 1 with the viscous ceramic filling compound and pressed onto the veneer frame 1 1, so that the excess filling material is pressed out.

In still other embodiments, the ceramic filling compound can also have a coloring property, so that the ceramic shell 10 can be adapted with regard to its basic color.

Due to the flexible nature of the ceramic shell 10, the shape of the shape, for example, at the preparation border by bending and cutting can thus be adjusted individually. However, it is important that the use of the viscous ceramic filling compound prevents an uncontrolled change in shape of the vestibular anatomical tooth form 15 due to sink marks caused by undercuts of the underlying framework or of the carrier. An uneven gap 14 would be transferred to the vestibular anatomical tooth shape 15 so that the key used as a veneer Ramikschale 10 would be attached with a modified outer shape of the veneer or the carrier.

Due to the viscous ceramic filling compound, undesired thermal deformation due to melting and shrinkage is largely compensated. It can also be provided to add UV initiators for light polymerization of the filling compound, so that the ceramic shell 10 is fixed on the veneering framework 1 1 in plastic form matching and positional positioning until the first firing step.

4, a second embodiment is shown. In this case, in contrast to the above-described embodiment of FIG. 3, the ceramic shell 10 is not applied to a veneer structure but on a refractory molded body 16 as a carrier. The further process control or attachment is identical.

Accordingly, the ceramic shell 10 can be used both for the formation of all-ceramic dentures as well as for the veneering of a dental framework.

After the first firing step, further firing steps for color and shape correction can be carried out. The ceramic shell 10 produced as a foil ceramic is elastic and can thus be adapted individually to the three-dimensional shape profile of the preparation boundary by bending and cutting. It is in principle possible to add to the ceramic sol a suitable UV initiator for light polymerization in order to fix the ceramic shell 10, which is subsequently plastically adapted to the framework or support in the mold, until the first firing. The remaining open spaces of the framework can then be conventionally veneered with a conventional powder-ceramic-water mixture with a ceramic brush, or be completed with a thixotropic ceramic sol in the desired tooth shape.

Since shrinkage of up to 16% is to be expected during the first main vacuum firing, the approximal areas and the incisal strip can be constructed with suitable effect masses in order to compensate for this shrinkage together with the green building during the first firing.

Furthermore, the use of the industrially manufactured flexible ceramic shell offers the considerable advantage of the very homogeneous ceramic structure, which leads to a uniform shrinkage. In contrast, the manual, anatomical layering has the significant disadvantage that here portionally finds a mixed in different viscosity and solid / water content powdered ceramic application, which then leads to different degrees of shrinkage and cracking.

The aim here is to achieve a color stable and dimensionally stable restoration with a tape guide (first main vacuum belt) and to complete possible form and color corrections in the second and final firing as combined color correction gloss firing by means of LFC ceramics (LFC = low fusing ceramic <750) ° C)

The features mentioned above and the claims which can be taken from the images are advantageously realizable both individually and in various combinations. The invention is not limited to the exemplary embodiments described, but can be modified in many ways within the scope of expert knowledge.

Claims

Claims:

1 . Anatomically preformed ceramic shell for the production of dental prostheses, in particular for veneering a dental framework or as a full-ceramic dental prosthesis, which as a green body of a ceramic powder and a

Binder system is made and the ceramic shell is anadaptierbar to a body as a whole without loss of the characteristic anatomical shape, especially in marginal areas.

2. Ceramic shell according to claim 1, wherein the green body is monochrome or polychrome.

3. Ceramic shell according to claim 1 or 2, wherein the green compact by means of a viscous ceramic filling material, in particular a ceramic sol, with the dental framework or a refractory molded body is applicable.

4. Ceramic shell according to claim 3, wherein the viscous ceramic filling compound UV initiators are added for light polymerization.

5. ceramic shell according to claim 3 or 4, wherein the viscous ceramic filler has thixotropic properties.

6. ceramic shell according to claim 3 to 5, wherein the viscous ceramic filling material acts as a balancing mass.

7. ceramic shell according to claim 3 to 6, wherein the viscous ceramic filling material causes a color adjustment.

A ceramic shell according to any one of claims 1 to 7, wherein the binder system is a polymer binder, an organic binder or a wax-based binder.

9. ceramic shell according to one of claims 1 to 8, which has a layer thickness of 0.1 mm to 3 mm.

10. ceramic shell according to one of claims 1 to 9, which has a zahnfarbgeben- de property.

1 1 .Process for producing a ceramic shell for dentures, in particular for veneering a dental framework or as a full ceramic dental prosthesis, comprising the steps:

- Providing a ceramic slip;

- preparing the ceramic slip to a slurry film;

- possibly pre-drying the slip film to adjust the degree of moisture or viscosity;

- Forming a concave flexible ceramic shell in anatomical shape;

- Removal of the flexible ceramic shell in the form of a green body; and - adapting the flexible ceramic shell to a solid or sheet.

12. The method of claim 1 1, wherein the step of preparing the

Ceramic slurry comprises forming at least two juxtaposed or superimposed Schlickerfilme having different colors or transparency.

13. The method of claim 1 1 or 12, wherein for forming the concave ceramic shell, a depression of the slurry film takes place in a negative mold.

14. The method of claim 13, wherein the negative form as a carrier film is part of a circulating conveyor belt.

15. The method according to any one of claims 1 13 or 14, wherein the impressions and / or recompression of the slip film is effected by means of an embossing roller.

16. The method according to any one of claims 13 to 15, wherein the negative mold transmits a vestibular tooth shape on the slurry film.

17. The method of claim 1 1 or 12, wherein the forming of the concave ceramic shell deep drawing or insertion into mold plates.

18. The method according to any one of claims 1 1 to 17, wherein the flexible ceramic shell is connected by means of a viscous ceramic filling material, in particular a ceramic sol, with a dental framework or a refractory mold or mass.