Method for producing a prosthesis or partial prosthesis

Abstract

A method for producing a prosthesis or partial prosthesis based on digital data, using multiple teeth present in a dental arch (14) and a prosthesis base to be produced. The prosthesis base is rough-milled by a milling tool, i.e. is milled in a first step, and the prosthesis base present as a semi-finished product, in particular in regions of the prosthesis base on which the teeth and the prosthesis base abut against each another and/or are to be bonded to each other, is partially milled, i.e. is milled in a second step, by a different milling tool, thereby being brought to a target height which corresponds to the desired bonding gap between the prosthesis base and the tooth or dental arch (14).

Claims

1. A method for producing a prosthesis or partial prosthesis based on digital data, having a plurality of teeth in a dental arch and a prosthesis base comprising rough-milling the prosthesis base with a first milling tool, to a semi-finished prosthesis base, finish-milling the semi-finished prosthesis base with a second milling tool in regions of the prosthesis base, on which the teeth and the prosthesis base abut against one another and/or are to be bonded to one another, wherein the semi-finished prosthesis base is milled to a target height in the finish-milling step, which target height corresponds to the abutment between the prosthesis base and the teeth or dental arch plus the desired bonding gap between the prosthesis base and the teeth or dental arch.

2. The method according to claim 1, comprising rough-milling the dental arch from a tooth-colored blank, and finish-milling a basal surface of the teeth of the dental arch and any gingival regions of the dental arch adjacent to the basal surface of the teeth.

3. The method according to claim 2, comprising gluing the dental arch with adhesive into dental cavities of the prosthesis base, curing the adhesive to connect the dental arch and prosthesis base, and finish-milling at locations where only rough-milled areas exist.

4. The method according to claim 2, comprising using a roughing cutter during rough-milling of the prosthesis base having a cutting depth between 0.7 mm and 2.5 mm or between 1.0 mm and 2.0 mm, using a finish-milling tool during finish-milling of the prosthesis base having a cutting depth between 0.1 mm and 0.5 mm, using a roughing cutter during rough-milling of the dental arch or partial dental arch having a cutting depth of between 0.6 mm and 2.2 mm, and/or using a finish-milling tool when finishing the dental arch or partial dental arch having a cutting depth between 0.1 mm and 0.4 mm.

5. The method according to claim 3, comprising providing an adhesive joint between the dental arch or partial dental arch and the prosthesis base having a thickness of between 0.08 mm and 0.22 mm, and using a relative position of the partial dental arch or dental arch in the cavities of the prosthesis base for height/side/angle correction of the connected dental or partial dental arch and prosthesis base.

6. The method according to claim 3, comprising following application of the adhesive and following bonding of the dental arch into the cavities of the prosthesis base and curing of the adhesive between the dental arch and the prosthesis base, finish-milling the dental arch in a workpiece holder of the milling machine while exclusively clamping the prosthesis base.

7. The method according to claim 3, comprising adapting a basal geometry of the dental arch to associated shapes of the cavities of the prosthesis base, or adapting the associated shapes of the cavities of the prosthesis base to the basal geometry of the dental arch, and, wherein the geometry and associated shapes are flatter and wider in the molar region and narrower and deeper in the incisor region.

8. The method according to claim 3, wherein the gingival regions of the dental arch are trapezoidally milled, forming preformed contact surfaces opposite the cavities in the prosthesis base.

9. The method according to claim 1, comprising fabricating the dental arch for producing the prosthesis from a material comprising plastic having a hardness/strength which is greater than a hardness/strength of the prosthesis base material, and wherein the material further comprises fillers.

10. The method according to claim 9, comprising fabricating the dental arch from a plastic material and polymethyl methacrylate (PMMA) bead polymer fillers and/or highly crosslinked prepolymer fillers which are surrounded by a diffusion layer.

11. The method according to claim 9, comprising fabricating the dental arch from a plastic material and PMMA bead polymer fillers and/or highly crosslinked prepolymer fillers which are surrounded by a diffusion layer, wherein the fillers are present in the plastic material in an amount of greater than 0 to up to 20 wt. % of the total weight of the plastic material and fillers.

12. A method for producing a prosthesis based on digital data comprising producing a substantially U-shaped dental arch for subsequently holding teeth from a tooth-colored material in the form of a blank, leaving behind holding bars between the U-shaped dental arch and the blank as a semi-finished product, rough-milling teeth in the U-shaped dental arch wherein the teeth have an oversize in relation to a size of the desired teeth of the prosthesis, fine-milling a basal region in the dental arch having a basal surface and surfaces adjoining the basal surface for being received in a prosthesis base, and gluing or fastening the dental arch into the prosthesis base.

13. The method according to claim 1 comprising, rough-milling the prosthesis base comprising milling a flat cylindrical disc of prosthesis base material into an outer contour that is substantially U-shaped.

14. The method according to claim 1, comprising using roughing cutters having tools with diameters between 0.8 mm and 6 mm, and using finishing cutters having tools with diameters between 0.5 mm and 3 mm or equal to or less than 2.5 mm.

15. The method according to claim 1, comprising leaving holding bars on the dental arch during rough-milling from a blank disc, wherein the dental arch produced by rough-milling comprises a rounded cross-section in an incisal area of the dental arch, and a basal surface and side surfaces converging towards said basal surface in a gingival area of the dental arch, and wherein the dental arch is essentially U-shaped.

16. The method according to claim 1, comprising prefabricating dental arches having substantially a U-shape in multiple sizes, and selecting the size of the dental arch most suitable for the prosthesis to be manufactured, wherein the prefabricated dental arches are prefabricated by milling or pressing processes.

17. The method according to claim 16, comprising prefabricating dental arches in at least 3 sizes.

18. The method for producing a prosthesis according to claim 12, producing the substantially U-shaped dental arch from a tooth-colored material blank fabricated of PMMA with fillers.

19. The method for producing a prosthesis according to claim 12, comprising finish-milling the glued or fastened prosthesis base and dental arch.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) Further details, advantages and features can be found in the following description of several example embodiments, by making reference to the drawings, wherein:

(2) FIG. 1 is a schematic view of a dental arch blank comprising a dental arch already partially milled out;

(3) FIG. 2 is a blank for two dental arches which—apart from the holding bars—have already been rough-milled;

(4) FIG. 3 is top view of a tooth arch or preformed tooth arch blank released from the blank disc, wherein the holding bars are still present or are to be provided;

(5) FIG. 4 is a section through the dental arch along the line IV-IV;

(6) FIG. 5 is a schematic view of a semi-finished prosthesis base;

(7) FIGS. 6 a and 6b are roughened dental arches comprising a basal side to be finish-milled, in frontal and bottom views; and

(8) FIG. 7 is a view of an exemplary roughing cutter.

DETAILED DESCRIPTION

(9) FIG. 1 shows a schematic representation of a tooth arch blank disk 10. The tooth arch blank disk, for example, has a diameter of 98.5 mm and a height of 20 mm, wherein it is to be understood that these dimensions can be adapted to the requirements in a wide range. The height of the disc should, in any case, cover the maximum height of the teeth to be created or the dental arch to be created, i.e. including the basal area.

(10) As can be seen from FIG. 1, a U is essentially milled out of the disc, with holding bars 12 holding the U to the remaining disc.

(11) Milling out was done by rough-milling, so that this could rapidly be completed, for example within 30 minutes.

(12) The U will subsequently be used as the dental arch 14 and has a size that is already adapted to the patient who is to wear the prosthesis later.

(13) A corresponding U for a mandibular prosthesis base is milled out of another gingival blank. This was also done by rough milling, in 15 to 40 minutes, especially in 30 minutes.

(14) The prosthesis base also comprises a holding bars that attaches it to the remaining blank disc.

(15) Milling out is done such that an arch cavity is initially prepared, i.e. pre-milling is carried out by rough-milling. Both parts, i.e. both the tooth-colored tooth arch blank disc and the gum-colored prosthesis base blank disc, now each carry a semi-finished product that is rough-milled and attached to the remaining disc by holding bars 12.

(16) In this state, both parts are simply milled, but only in the area where they are intended to be joined together. For the dental arch, the basal area is 18 (see FIG. 4), and for the prosthesis base, this is the tooth cavity, which herein may also be referred to as the dental arch cavity. Finish-milling is performed so that the basal surface of the dental arch is brought to the final dimension. Furthermore, in the example embodiment shown, an adhesive gap of 150 μm is left.

(17) Following completion, the dental arch is separated from the dental arch disc by removing the holding bars 12. It is provided with adhesive in the basal area, or the tooth cavity of the prosthesis base is provided with adhesive. The dental arch is then pressed into the tooth cavity with its basal area, displacing the adhesive, and held in a specific position in which the adhesive is to cure.

(18) Following curing, rough-milling is performed, which also in particular generously removes residual adhesive.

(19) In the next step, the bonded combination of dental arch and prosthesis base is finished by milling. After completion, the holding bars of the prosthesis base are also removed and neating is performed.

(20) If required, it is also possible to add a polishing step, if necessary.

(21) FIG. 2 shows how two tooth arches 14 can be accommodated in a blank disc 10.

(22) In the example embodiment shown, they are offset to each other and are also accommodated on the disc to save space.

(23) In another embodiment, FIG. 3 shows how a dental arch 14 can be equipped with holding bars 12.

(24) FIG. 4 schematically shows a section through the dental arch 14 according to line IV-IV. An incisal or occlusal area 16 is rounded, and is circularly rounded in the example shown. Herein, any embodiment is conceivable, such as curved surfaces indicating fissures.

(25) In contrast, the basal area 18 essentially has a trapezoidal shape. The basal surface 20 is flat, and basal lateral surfaces 22 and 24 extend sideways away therefrom, diverging away from each other towards the incisal area, into which they constantly merge at their ends.

(26) The shape shown is for the canine or premolar region. In contrast, the basal area is wider and flatter in the molar area and narrower and higher in the anterior area.

(27) This also applies to the corresponding incisal area of the dental arch 14, even if this is not shown in this embodiment in FIG. 3.

(28) At the transition between the basal surface 20 and the basal side surfaces 22 and 24, preferably a small radius is provided, such as 0.8 mm.

(29) A top view of a semi-finished prosthesis base can be seen from FIG. 5. In this state, the prosthesis base 26 already has a U-shaped recess 27, which is for the subsequent accommodation of the basal area 18, i.e. the basal surface 20 and the adjacent surfaces 22 to 24, of the likewise U-shaped dental arch 14.

(30) In this state, the prosthesis base has not yet been removed from the blank disc 28, but this is done in the next step.

(31) The majority of the prosthesis base 26 is initially rough-milled and the U-shaped recess 27 is already finish-milled.

(32) FIG. 6a shows an already rough-milled dental arch 14. The dental arch 14 already shows individual teeth 29. The teeth 29 are each attached to the tooth transitions 31. In this respect, the dental arch 14 is a monobloc including molars, premolars, canines and anterior teeth in the example embodiment shown.

(33) It is to be understood that, according to the invention, a partial tooth arch can also be used instead.

(34) In the basal area 18, the tooth arch 14, in the state shown, is also rough-milled, as can also be seen in FIG. 6b. It may be seen that the basal area 18 is realized as still being rather crowned and having corresponding oversize, while in the next step, the oversize is removed by finish-milling.

(35) Upon completion of finish-milling, the basal area 18 fits exactly into the U-shaped recess 27, leaving the adhesive joints as they are.

(36) FIG. 7 shows a side view of an exemplary roughing cutter 30. The roughing cutter 30 is designed as a single cutter and is diamond coated. In a manner known per se, it has a back bar 32, which protrudes by a bar height of 36 compared to the milling cutter 34.

(37) The bar height 36 depends on the diameter of the milling cutter. Herein, diameter is not to be understood as the diameter at the clamping shank 40, but in the front area. The diameter D of the roughing cutter can be about 1 mm to 6 mm. The bar height 36 is one twentieth to one sixth of diameter D.

(38) The roughing cutter is designed as a single cutter having a helical circumferential groove 42 which is for discharging the milling chips.

(39) According to the invention, single cutters are preferred, as they have the lowest tendency to clog.

(40) It is to be understood that, other roughing cutters may suitably be used instead, for example uncoated cutters or dual cutters or, if necessary ball milling cutters may also be used.

(41) However, coated roughing cutters are preferred at least for milling the tooth arches.

(42) A finishing cutter to be used in accordance with the invention can have essentially the same structure, wherein both the diameter D and the bar height 36 are preferably smaller for the finishing cutter in order to take account of the smaller plunging depth in the finish-milling step.

(43) Milling is preferably carried out in a master/slave process: First, the optimum joint between the prosthesis base and the dental arch-including the adhesive gap—is calculated using CAD.

(44) However, the minimum material thickness of the prosthesis base is used as the master: If, based on the initial draft, this falls below a specified minimum value at a point, for example 1 mm, 1.5 mm or 2 mm, the parting line is changed so that the minimum value is observed everywhere. This can also be done, for example, by changing steepness of the basal surface of the dental arch or, if necessary, by translational movement in the vestibular direction, especially in the area of the incisors including their already greater basal surface steepness.

(45) This process has a positive effect on the strength of the prosthesis base, while still providing optimized adhesive surfaces.