DENTAL PROSTHESIS MODIFIED WITH FILM AND HAVING IMPROVED PROPERTIES

Abstract

The invention relates to a dental prosthesis, in particular prefabricated tooth replacements, whereby a layer of a film is integrated into the dental prosthesis. Preferably, the dental prosthesis is built up layer-wise, whereby the prosthesis comprises an inner tooth portion, a film on the inner tooth portion, and a further tooth portion outside on the film, such as a veneer and/or incisor shell. The method for producing said dental prostheses is also a subject matter of the invention.

Claims

1. Dental prosthesis comprising at least one layer of a film integrated into the dental prosthesis.

2. Prosthesis according to claim 1, wherein the prosthesis is at least one part of a dental restoration, a single tooth, veneer, crown, a bridge, a multi-unit bridge.

3. Prosthesis according to claim 1, wherein the prosthesis is designed layer-by-layer and at least one part of the prosthesis comprises at least one layer of a film situated on the inside.

4. Prosthesis according to claim 1, wherein the dental prosthesis is a tooth with at least one integrated film, whereby the tooth comprises at least three portions (i)-(iii): (i) inner tooth portion, (ii) film layer, and (iii) at least one further tooth layer.

5. Prosthesis according to claim 4, wherein (i) the inner tooth portion comprises at least one polymer of an (alky)acrylate, and/or of a copolymer based on (meth)acrylates and cross-linkers, and/or (ii) the film layer comprises a tough-elastic and/or thermoplastic film, and/or (iii) the at least one further tooth layer comprises at least one polymer of an (alkyl)acrylate, copolymer, veneer composite and/or dental veneer ceramics.

6. Prosthesis according to claim 1, wherein (ii) the film layer comprises a film comprising PVC, acrylate, PE, PP, LDPE, HDPE, LDPP, HDPP, PUR, polycarbonate and/or a mixture comprising any one of said polymers.

7. Prosthesis according to claim 1, wherein the film is tinted.

8. Prosthesis according to claim 1, wherein the film is plasma-treated or chemically-modified on the surface.

9. Method for producing a dental prosthesis, which comprises the steps of: 1) providing a film, 2) integrating the film into the prosthesis by a) (i) producing an inner tooth portion in a first step, (ii) applying and affixing a film at least in part to the inner tooth portion or arranging a film on the inner tooth portion in a subsequent step, and, optionally, (iii) applying at least one further tooth layer, at least in part, to the film and, optionally, to the regions of the inner tooth portion not provided with film, or b) (i) providing at least one further tooth layer, (ii) applying a film on the further tooth layer, (iii) arranging an inner tooth portion on the film, or c) (i) arranging a film and (ii) surrounding the film with the inner tooth portion and/or the at least one further tooth layer, or d) (i) producing at least one part of an inner tooth portion in a first step, (ii) applying and affixing a film at least in part to the inner tooth portion or arranging a film on the inner tooth portion in a subsequent step, and, optionally, (iii) applying at least one further part of the inner tooth portion to the film and, optionally, to the regions of the inner tooth portion not provided with film.

10. Method according to claim 9, wherein the film is integrated into the dental prosthesis, at least in part.

11. Method according to claim 9, wherein the film comprises a tough-elastic and/or thermoplastic film.

12. Method according to claim 9 to 11, wherein (i) the inner tooth portion is produced from a polymerisable composition comprising a) 50 to 90% by weight powdered polymer, and 10 to 50% by weight monomers; or b) 0 to 50% by weight organic or inorganic filling agents; 50 to 99% by weight PMMA; 10 to 50% by weight monomers, whereby the total composition adds up to 100% by weight; (ii) the inner tooth layer comprises a polymer of an acrylate, and/or (iii) the at least one further tooth layer comprises a polymer of an acrylate.

13. Method according to claim 9, wherein the method produces a tooth comprising an inner tooth portion that is provided, at least in part, with a film layer, and the film layer is covered, at least in part, by a further tooth layer, whereby, optionally, a multitude of prostheses, optionally prefabricated tooth replacements, is produced through the integration of a film.

14. Method according to claim 9, wherein c) (i) arranging the film involves the film, optionally a web of film, being clamped between the respective negative moulds of one or more hollow moulds of prefabricated tooth replacements, and (ii) the film is being surrounded with the inner tooth portion and/or the at least one further tooth layer.

15. Prosthesis obtainable according to a method according to claim 9.

16. (canceled)

Description

[0061] The invention is illustrated in more detail in the following examples without being limited to said exemplary embodiments. The invention shall also be illustrated in more detail based on the following figures.

[0062] FIG. 1a: Partially finished tooth with integrated film

[0063] FIG. 1b: Finished tooth with integrated film, no effect on the optical properties

[0064] FIG. 1c, 1d: Sectional view of a tooth with visible transparent film

[0065] FIG. 1e: Fractured tooth, frontal view

[0066] FIG. 1f: Fractured tooth, side view

[0067] FIG. 1g: Fractured tooth-fragment is still connected to the stump by the film material

[0068] FIG. 1h: Fractured tooth-fragment is still connected to the stump by the film material

[0069] FIG. 2a: Partially finished tooth with integrated coloured film

[0070] FIG. 2b: Finished tooth with integrated coloured film

[0071] FIG. 3: Schematic view of a sectional image of a prefabricated tooth replacement 0 comprising an incisor shell 1 in the form of a further tooth layer, a film layer 2, and an inner tooth portion 3.

EXAMPLES

[0072] In the scope of the layer-wise production of artificial teeth, a film layer was introduced into a negative mould for tooth prostheses and integrated into the tooth. A modified PVC film with a thickness of 140 m and a melting range from 120 to 170 C. was used, although other film materials capable of connecting homogeneously to the surrounding tooth material are feasible as well.

[0073] In the first step of the production, a paste based on PMMA and a methacrylate mixture was introduced into the production mould. A simple example of a suitable dough mass is a mixture of 60-70% PMMA bead polymers and 30-40% methacrylate-based monomers, and cross-linkers (e.g. methylmethacrylate and glycoldimethacrylate). This mixture was made to have a suitable viscoelastic consistency through the use of swelling processes.

[0074] After application of an additional separating film and placing the upper part of the mould, the first layer was pre-polymerised at 90 C.-120 C. The pre-polymerisation took place in a hydraulic heating press as a radical polymerisation initiated by peroxide.

[0075] After removal of the separating film, the special film to be incorporated was placed on the pre-polymerised layer and the subsequent layer was also applied either in the form of a paste or it was injected into the already closed mould using injection channels, if present. In this context, it is important to build up enough pressure in the mould and to allow the pasty material some time to act on the film during the heating phase of the mould. Approximately 3-5 minutes are sufficient until the nominal polymerisation temperature is reached. The mould can be opened once the mass present in the mould is cured. The film is firmly bonded between the 2 layers of material.

[0076] If needed, further layers can be added in like manner. After the production of the last layer of the tooth is completed, the teeth are detached from the surrounding plastic material.

[0077] The burrs remaining on the tooth due to the separating edges of the mould are subsequently removed either by means of automatic burr removal or by manual burr removal using manual polishing devices. Automatic burr removal preferably takes place by means of a laser, but can also be done using any common vibratory finishing or barrel deburring procedure.

[0078] Visual analysis of the sectioned images in FIGS. 1c and 1d clearly shows the profile of the film layer between the first tooth layer (incisor shell) and the second tooth layer (dentine). If the tooth breaks by force, the fragment remains flexibly attached to the residual tooth, as is evident from FIGS. 1g and 1h.

[0079] The fragment can be severed only by further pulling the parts apart and by tearing the film.

[0080] The modification of the teeth by the films according to the invention did not affect the aesthetic properties and did not reduce the strength of the tooth. The product meets the materials requirements of EN ISO 22112.

[0081] FIG. 3 shows a schematic view of a prefabricated tooth replacement according to the invention that was produced using a method according to the invention. The film layer 2 is integrated underneath the layer of the incisor shell 1, which corresponds to a further tooth layer. The film layer 2 is applied to the inner tooth portion 3.