PREPARATION OF A WAX OR PLASTIC BASE FOR PRODUCING A DENTAL PROSTHESIS

Abstract

The invention relates to a method for producing a wax base or a prosthesis base for producing a dental prosthesis, with which a virtual CAD model of the dental prosthesis is used for the production of the physical dental prosthesis or the physical prosthesis base, wherein, from the CAD model of the dental prosthesis, a virtual model of the prosthesis base is calculated, characterized by the following chronological steps: A) Scanning in of at least one three-dimensional region of a physical model of the oral cavity situation of a patient and preparation of a first data record on the basis of this scan, or intra-oral scan of a three-dimensional region of the oral cavity situation of the patient and production of a physical model of the oral cavity situation of a patient on the basis of the intra-oral scan and preparation of a first data record on the basis of the intra-oral scan; B) application of a wax layer or a plastic layer onto the physical model of the oral cavity situation; D) calculation of a virtual surface as a surface which is to be formed in the wax layer or in the plastic layer, wherein the calculation is made on the basis of the virtual model of the prosthesis base and of the first data record, and wherein positioning aids are provided in the surface which is to be produced, for the positioning of prosthetic teeth; and E) production of the wax base from the wax layer or of the prosthesis base from the plastic layer with a subtractive CAM method, on the basis of the virtual surface calculated in step D).

The invention also relates to a method for producing a dental prosthesis or a wax set-up for a dental prosthesis, and a prosthesis base, a wax base, or a dental prosthesis, produced with such a method.

Claims

1. Method for producing a wax base or a prosthesis base for producing a dental prosthesis, with which a virtual CAD model of the dental prosthesis is used for producing the physical dental prosthesis or the physical prosthesis base, wherein, from the CAD model of the dental prosthesis, a virtual model of the prosthesis base is calculated, the method comprising the following chronological steps: A) scanning at least one three-dimensional region of a physical model of an oral cavity situation of a patient and preparing a first data record D1 on the basis of this scan, or intra-oral scanning a three-dimensional region of the oral cavity situation of the patient and producing a physical model of the oral cavity situation of the patient on the basis of the intra-oral scan and preparing a first data record D1 on the basis of the intra-oral scan; B) applying a wax layer or a plastic layer onto the physical model of the oral cavity situation; D) calculating a virtual surface as a surface which is to be formed in the wax layer or in the plastic layer, wherein the calculation is made on the basis of the virtual model of the prosthesis base and of the first data record D1, and wherein positioning aids are provided in the surface which is to be produced, for the positioning of prosthetic teeth; and E) producing the wax base from the wax layer or of the prosthesis base from the plastic layer with a subtractive CAM method, on the basis of the virtual surface calculated in step D).

2. Method according to claim 1, further comprising a step C), which takes place between steps B) and D): C) scanning at least one region of the physical model, with the wax layer or the plastic layer applied, of the oral cavity situation and producing a second data record D2 on the basis of this scan.

3. Method according to claim 2, comprising in step C), scanning the free surface of the wax layer or the plastic layer in at least some regions on the physical model of the oral cavity, and processing the scan to the second data record D2, wherein a calculation of the virtual surface, as the surface to be produced, takes place in the wax layer or in the plastic layer, on the basis of the CAD model of the prosthesis base, on the basis of the first data record D1, and on the basis of the second data record D2.

4. Method according to claim 1, comprising locating the surface which is produced in the wax layer or the plastic layer opposite the contact surface of the wax layer or the plastic layer on the physical model of the oral cavity.

5. Method according to claim 1, wherein the positioning aids exhibit a distinctive form, in such a way that the location and the position of the prosthetic teeth in relation to one another is distinctively and unambiguously determined when the prosthetic teeth are inserted with flush surfaces into the positioning aids of the prosthesis base or when the prosthetic teeth are inserted with flush surfaces into the positioning aids of the wax base.

6. Method according to claim 1, comprising producing the wax base from the wax layer or the prosthesis base from the plastic layer with a subtractive CAM method, while the wax layer or the plastic layer is arranged on the physical model of the oral cavity.

7. Method according to claim 1, comprising scanning at least those surfaces onto which the wax layer or the plastic layer are subsequently applied in respect of the physical model.

8. Method according to claim 1, comprising applying the wax layer or the plastic layer onto the physical model of the oral cavity situation with the aid of preformed wax bodies or with the aid of soft preformed plastic bodies.

9. Method according to claim 1, comprising acquiring the physical model of the oral cavity before step A) by an impression of the upper jaw and/or an impression of the upper jaw in the oral cavity of the patient.

10. Method according to claim 1, comprising producing the virtual CAD model of the dental prosthesis and/or the virtual model of the prosthesis base on the basis of the data record D1 of the scan of the physical model of the oral cavity situation or of the intra-oral scan of the oral cavity situation, by a CAD process.

11. Method according to claim 1, comprising using a computer-controlled milling device to implement the subtractive CAM process.

12. Method according to claim 1, comprising, for producing the wax base or the prosthesis base, arranging at least one securing means at the physical model of the oral cavity situation, or securing at least one securing means to a rail and/or an anchoring device, which is/are arranged at the physical model of the oral cavity situation, and, following this, in step B), applying the wax layer or the plastic layer onto the physical model of the oral cavity situation in such a way that the wax layer or the plastic layer is connected to the at least one securing means.

13. Method according to claim 12, comprising carrying out the scan of the physical model of the oral cavity situation or the intra-oral scan with implants with at least one web inserted, and/or with at least one anchoring device at the physical model or in the oral cavity.

14. Method for producing a dental prosthesis or a wax set-up for a dental prosthesis with a method according to claim 1, comprising, after step E): F) inserting prosthetic teeth into the positioning aids of the wax base, which in step E) were produced in the surface of the wax layer for producing the wax set-up, or inserting and securing prosthetic teeth into the positioning aids of the prosthesis base, which in step E) were produced in the surface of the plastic layer for producing the dental prosthesis.

15. Method for producing a dental prosthesis from a wax set-up produced with a method according to claim 14, comprising: after step F), casting the wax set-up with the prosthetic teeth into a mold, removing the wax of the wax base is removed, wherein the prosthetic teeth remain in the mold, and the location and position of the prosthetic teeth in the mouth remain unchanged, casting the cavity which is created in the mold with a plastic, which forms the prosthesis base of the dental prostheses, hardening the plastic, whereby the prosthetic teeth are securely connected to the plastic, and, opening the mold and removing the dental prosthesis from the mold.

16. Wax base or prosthesis base produced with a method according to claim 1.

17. Dental prosthesis produced with a method according to claim 14.

18. Dental prosthesis produced with a method according to claim 15.

19. Method according to claim 8, comprising applying the wax layer or the plastic layer onto the physical model of the oral cavity situation with the aid of at least one wax plate, or with the aid of at least one plastic plate and/or a molding spoon.

20. Method according to claim 9, wherein the impression is cast with gypsum plaster or a plastic to produce a gypsum model or a plastic model as a physical model of the oral cavity situation.

21. Method according to claim 11, comprising using a computer-controlled 4-axis or 5-axis milling device to implement the subtractive CAM process.

22. Method according to claim 12, comprising, for producing the wax base or the prosthesis base, arranging at least one securing means at the physical model of the oral cavity situation at points of the physical model of the oral cavity situation which correspond to the implants, or securing at least one securing means to a rail and/or an anchoring device, which is/are arranged at the physical model of the oral cavity situation at points of the physical model of the oral cavity situation which correspond to the implants, and, following this, in step B), applying the wax layer or the plastic layer onto the physical model of the oral cavity situation in such a way that the wax layer or the plastic layer is connected to the at least one securing means.

23. Method according to claim 13, comprising carrying out the scan of the physical model of the oral cavity situation or the intra-oral scan with implants with at least one web inserted, and/or with at least one anchoring device at the physical model or in the oral cavity with at least one securing means secured to the implants, to the at least one inserted web, and/or to the at least one anchoring device.

24. Method for producing a dental prosthesis or a wax set-up for a dental prosthesis with a method according to claim 14, wherein step F comprises inserting and adhesive bonding in place, the prosthetic teeth into the positioning aids of the prosthesis base.

25. Method for producing a dental prosthesis or a wax set-up for a dental prosthesis with a method according to claim 14, comprising, after inserting and securing the prosthetic teeth, polishing the dental prosthesis and/or hardening the connection of the prosthetic teeth to the prosthesis base.

26. Method for producing a dental prosthesis from a wax set-up produced with a method according to claim 15, comprising removing the wax of the wax base is removed by melting the wax and by releasing the wax with water vapor or steam.

27. Method for producing a dental prosthesis from a wax set-up produced with a method according to claim 15, comprising opening the mold and removing the dental prosthesis from the mold and processing the dental prosthesis after removal from the mold by polishing and/or deburring.

Description

[0068] Further exemplary embodiments of the invention are explained hereinafter on the basis of five schematically represented Figures, but without thereby restricting the invention. The Figures show:

[0069] FIG. 1: A perspective view of a prosthesis base or wax base for a lower jaw without prosthetic teeth, such as derived from the virtual model of the prosthesis base and such as derived with the carrying out of a method according to the invention; and

[0070] FIGS. 2 to 5: The chronological sequence of a method according to the invention, on the basis of a physical model oral cavity situation, set up on a prosthesis base or wax base and schematically represented in cross-section.

[0071] FIG. 1 shows a schematic perspective view of a wax base 1 or a prosthesis base 1 made of plastic with a method according to the invention and provided for producing a wax set-up according to the invention or a dental prosthesis according to the invention. Likewise represented in FIG. 1 can also be the virtual model of the prosthesis base. If the prosthesis base 1 is made of plastic, it consists of a pink-colored plastic. The coloring and transparency are selected such as to match the appearance of a gum.

[0072] Provided in the upper side of the wax base 1 or prosthesis base 1 are a plurality of tooth sockets 2 for the fixing of prosthetic teeth (not shown in FIG. 1). The tooth sockets 2 are in this situation formed as depressions in the jaw saddle of the wax base 1 or prosthesis base 1. The tooth sockets 2 can exhibit an indexing arrangement, such that the prosthetic teeth are to be inserted only in one specific orientation region in the wax base 1 or the prosthesis base 1, and, as far as possible, each prosthetic tooth fits only to one specific tooth socket 2.

[0073] The tooth sockets 2 exhibit in the indentations centrally arranged projections, which match with corresponding indentations in the basal ends of the prosthetic teeth (not shown in FIG. 1). As a result, it can be specified still more clearly and identifiably which prosthetic teeth should be inserted into which tooth sockets 2, and in what orientation the prosthetic teeth should be inserted into the tooth sockets 2. Specifically, with appropriate symmetry breaking, the elevations can serve as indexing elements. In addition, in this way a more stable connection of the wax base 1 or of the prosthesis base 1 to the prosthetic teeth can be produced. This is also of significance with regard to the wax base 1, since the prosthesis base produced later with the aid of the wax base has the same shape as the wax base 1, and, at the latest at the production of the prosthesis base, a stable connection to the prosthetic teeth is desirable at the production of the dental prosthesis.

[0074] FIGS. 2 to 5 show the chronological sequence of a method according to the invention on the basis of a physical model of the oral cavity situation, represented schematically in cross-section, onto which a prosthesis base or wax base, and later a wax set-up or a dental prosthesis are built up. The cross-section plane represented lies in a plane parallel to the frontal plane of the patient.

[0075] Represented in FIG. 2 is the scanning in of a physical model 4 of a toothless upper jaw of a patient. The physical model 4 was produced previously with the aid of an impression-taking compound and an impression tray, and filling of the shaped compound. Preferably, the shaped impression-taking compound is filled with gypsum plaster, such that a plaster model 4 is obtained. In the physical model 4, the jaw arch 6 and the jaw ridge 6 respectively, and the palate 8 of the oral cavity situation of the patient can be identified.

[0076] The physical model 4 is set up or fixed in a defined position, and then, with a scanner 10, the surface of the physical model 4 is recorded. For this purpose, the scanner 10 and/or the model 4 are moved relative to one another, such that all the relevant areas of the surface of the model 4, i.e. in particular the surfaces on which later the prosthesis base or the wax base, or, respectively, the dental prosthesis is intended to lie, can be recorded. The data D1 which is derived from the scan is stored.

[0077] As an alternative, the oral cavity situation of the patient can also be recorded with the aid of an intra-oral scan. The data record D1 is then calculated from the intra-oral scan, or determined on the basis of the scan. In this situation, it is also possible for evident errors in the model, which, for example, can be identified by the user graphically on a display screen, to be removed manually by the user. The data from the intra-oral scan is then additionally used in order to produce a virtual CAD model of the oral cavity situation and of a physical model 4 to be produced of the oral cavity situation. By means of a suitable CAM process, the physical model 4 of the oral cavity situation is then produced generatively or subtractively.

[0078] The data D1, regardless of whether acquired on the basis of a scan of the model 4 or on the basis of the intra-oral scan, can then be used to produce the virtual model of the dental prosthesis which is to be formed, using a CAD process. For this purpose, the data of a physical model of the lower jaw (not shown in the FIGS. 2 to 5), data regarding the articulation of the upper jaw and of the lower jaw of the patient, and data regarding the shape of prosthetic teeth to be inserted (i.e. virtual models of prosthetic teeth) are required and used. By calculated drawing off, or calculated separation of the molds of the prosthetic teeth from the CAD model, a virtual model of the prosthesis base is obtained.

[0079] Next, a wax layer 12 or a plastic layer 12 is applied onto the physical model 4; that is to say, a base plate 12 of wax or plastic is adapted on the physical model 4. This is represented in FIG. 3. The wax layer 12 or plastic layer 12 has a thickness of 10 mm and is therefore in any event thicker than the wax base 1 or prosthesis base 1 to be produced, at its thickest point. This therefore ensures that later no material is missing at any point of the wax base 1 or prosthesis base 1 which is to be produced.

[0080] The wax layer 12 or the plastic layer 12 lies on the jaw arch 6 or jaw ridge 6 and the palate 8 of the physical model 4 of the oral cavity, which then specifies for the user the relevant anatomical structures of the oral cavity of the patient. The physical model 4 holds the layer 12 stable, and later also the wax base 1 or prosthesis base 1 to be produced from it. To produce a prosthesis base for the lower jaw, a corresponding model (not shown) of the lower jaw is used.

[0081] With the scanner 10, the surface of the model 4, with the wax layer 12 or plastic layer 12, is then scanned onto this (represented in FIG. 3). In this situation, the entire surface of the wax layer 12 or plastic layer 12 is recorded, which lies opposite the contact surface on the physical model 4. This scan is stored as a data record D2.

[0082] From the data D1 of the surface of the physical model 4, the virtual model of the prosthesis base and the data D2 of the surface of the wax layer 12 or the plastic layer 12 on the physical model 4, it is then calculated how much material (wax or plastic) and at what points the material must be removed from the wax layer 12 or plastic layer 12, and this result is stored as a data record D3.

[0083] Based on the data D3, with a computer-controlled milling device 14 (such as a computer-controlled 4-axis or 5-axis milling device), the wax layer 12 or plastic layer 12 is processed or milled while it is still lying on the physical model 4. For this purpose, the physical model 4 of the oral cavity situation and the wax layer 12 or plastic layer 12 are secured on a mounting (not shown) of the milling device 14 and fixed.

[0084] Processing in a very advanced state is represented in FIG. 4. As well as the desired shape of the wax base 1 or prosthesis base 1 of plastic produced in this way, tooth sockets 2 are also produced in the wax base 1 or prosthesis base 1. Such a completed wax base 1 or prosthesis base 1 with the tooth sockets 2 is represented in FIG. 1. The surface lying on the physical model 4 of the oral cavity does not need to be processed with the milling device, and therefore remains very smooth.

[0085] If appropriate, polishing can be applied on this side. As a result, there is no requirement for processing of one side of the prosthesis base 1 or the wax base 1 respectively, which can save a considerable amount of time.

[0086] In a next step, prosthetic teeth 16 are inserted into the tooth sockets 2 and then secured. This is represented in FIG. 5.

[0087] The cut prosthetic teeth 16 are configured here as molars or posterior or buccal teeth prostheses. The prosthetic teeth 16 consist of a hard white plastic, with the appropriate coloring and transparency to match teeth, or specifically the teeth of the patient. Each prosthetic tooth 16 comprises a coronal or occlusal surface 18 respectively (chewing surface) and a basal surface 20. The basal surface 20 is fixed in the tooth sockets 2.

[0088] The tooth sockets 2 are the basal counter-pieces of the basal sides 20 of the prosthetic teeth 16. Before the first insertion of the prosthetic teeth 16 into the tooth sockets 2 in the prosthesis base 1 of plastic, the tooth sockets 2 and the prosthetic teeth 16 (at least the basal sides 20 of the prosthetic teeth 16) are cleaned and, in order to improve the connection, are roughened and swelled with a solvent, and then connected with an adhesive.

[0089] Surplus residues of adhesive which emerged due to squeezing can be removed before and/or after hardening.

[0090] The completed dental prosthesis or the wax set-up can then be inserted in the patient's mouth for checking the fit. The wax set-up (wax base 1 with prosthetic teeth 12 inserted) offers still further possibilities for correction by the dental technician and/or the dentist. Based on the wax set-up, using known methods, with the aid of a flask as a mold, and by removing the wax from the mold, a dental prosthesis is produced, in that the cavity with the prosthetic teeth 12 fixed in it is filled with plastic and connected to the prosthetic teeth 12. Subsequent processing of the finished dental prosthesis (polishing and deburring) can then take place.

[0091] The method according to the invention can also be applied to printed prosthetic teeth or prosthetic teeth rows, but is preferably carried out with pre-assembled prosthetic teeth, which can be basally shortened beforehand, manually or with an automatic milling process.

[0092] The features of the invention disclosed in the foregoing description, as well as in the claims, Figures, and exemplary embodiments, can be essential individually as well as in any desired combination for the realization of the invention in its various different forms.

REFERENCE NUMBER LIST

[0093] 1 Wax base/prosthesis base

[0094] 2 Tooth socket for the fixing of prosthetic teeth

[0095] 4 Physical model of the upper jaw/oral cavity

[0096] 6 Jaw arch/jaw ridge of the model of the oral cavity

[0097] 8 Palate of the model of the oral cavity

[0098] 10 Scanner

[0099] 12 Wax layer/plastic layer

[0100] 14 Milling device/milling head

[0101] 16 Prosthetic tooth

[0102] 18 Coronal surface of the prosthetic tooth

[0103] 20 Basal surface/basal side of the prosthetic tooth