ARTIFICIAL TOOTH ELEMENT

Description

[0001] The invention relates to an artificial tooth element and a prosthesis comprising a prosthesis base and artificial tooth elements. The tooth elements are, in particular, individual artificial teeth or units or blocks consisting of several artificial teeth.

[0002] With standard prefabricated artificial teeth, it is necessary for the dental technician to shorten the basal surface and roughen it. Shortening is required to adapt the basal inner part of the tooth element—that is, the part of the tooth element that is inserted into the denture base and is not visible when in place—to the cavity provided in the denture base. Roughening is necessary to achieve sufficient strength and stability after cementation, particularly after inserting and bonding the tooth element to the denture base. The disadvantage of having a dental technician shorten and roughen the inner part of the tooth element is that the accuracy always depends on the technician's skill, potentially resulting in highly variable quality.Furthermore, such cutting and roughening of the artificial tooth element by the dental technician involves considerable costs.

[0003] An artificial tooth element with the features of the preamble of claim 1 is known from EP 3 130 312 or DE 10 2014 118231 B3.

[0004] The object of the invention is to create an artificial tooth element in which machining of the inner part by a dental technician is not required or only required to a small extent.

[0005] The problem is solved by an artificial tooth element according to claim 1.

[0006] The artificial tooth element according to the invention comprises an outer part and an inner part. The outer part is the part of the tooth element that is visible when inserted, i.e., when the tooth element is placed in a cavity of a denture base. Correspondingly, the inner part of the tooth element is the part that is not visible when inserted. Regardless of the inserted state, the outer and inner parts are also defined by the virtual gingival line. The part of the tooth element that is basal with respect to the virtual gingival line is the inner part, and the part that is incisal / occlusal with respect to the virtual gingival line is the outer part of the tooth element. The virtual gingival line, which preferably represents the dividing line between the inner and outer parts, is preferably completely circumferential.

[0007] According to the invention, the inner part of the artificial tooth element has a defined surface roughness, at least partially, and in particular completely. The surface roughness is thus created by the manufacturer. The artificial tooth element therefore has a defined roughness at the factory. Consequently, post-processing of the inner part's surface by a dental technician is generally no longer necessary. Rather, such an artificial tooth element according to the invention can be used directly, i.e., directly attached to the corresponding cavity of the denture base, i.e., inserted and bonded in place.

[0008] The virtual gingival line varies among patients, particularly depending on their age. Therefore, the virtual gingival line is well-suited to define the relevant inner and outer parts of the tooth element according to the invention. It is preferred that the artificial tooth element is roughened in a specific area or has a defined surface roughness that extends slightly beyond the virtual gingival line towards the outer part. This ensures that the surface relevant for attachment, i.e., in particular, insertion and bonding of the artificial tooth element into the cavity, has the required roughness. The fact that a small area of ​​the visible outer part is also roughened is not of particular importance, since the artificial tooth element will need to be finished, especially polished, after attachment anyway.This is necessary, for example, to remove adhesive residue. Therefore, it is advantageous that the defined surface roughness is provided on a slightly larger surface area than the inner part to ensure a secure bond.

[0009] The area exhibiting the defined surface roughness preferably has at least the size of the bonding surface and is preferably somewhat larger. Preferably, the bonding surface projects slightly beyond the virtual gingival line into the outer part. This projection can be 0.5 to 1 mm. In one embodiment of the artificial tooth element according to the invention, the surface roughness has an arithmetic mean roughness value Ra of 1 to 4 µm, and preferably 2 to 3 µm.

[0010] The average roughness Ra is determined by: Method: Profile-based stylus method Measuring device: HOMMEL-ETAMIC TURBO WAVE V7.62 Measuring probe: TKU100 Measuring distance 7.5 µm Measuring speed vt: 0.15 mm / s

[0011] The roughness depth Rz is preferably in the range of 5 to 25 µm, in particular 5 to 20 µm.

[0012] The lower limit of the arithmetic mean roughness Ra is at least 1 µm.

[0013] The upper limit is ≤4 µm, and preferably ≤3 µm.

[0014] The visible outer part is preferably smoother than the inner part of the artificial tooth element according to the invention. Preferably, the arithmetic mean roughness Ra of the inner part is greater than the arithmetic mean roughness Ra of the outer part. In particular, this value is 30% higher and, more preferably, 50% higher, so that the inner part is significantly rougher than the outer part.

[0015] In a preferred embodiment of the artificial tooth element according to the invention, the inner part has a minimum outer radius of at least 0.6 mm. The smallest radius present in the area of ​​the inner part is thus 0.6 mm or more. This is particularly advantageous for the fabrication of the cavity in a denture base. It is especially preferred that the minimum outer radius is at least 1.0 mm and, in particular, at least 1.25 mm.

[0016] Furthermore, it is preferred that the inner part of the artificial tooth element is asymmetrically designed. In particular, the inner part is not rotationally symmetrical. This prevents incorrect insertion into the denture base.

[0017] Furthermore, a denture base is provided for the manufacture of a prosthesis. The denture base has several cavities for receiving an artificial tooth element, as described above and advantageously further developed. Preferably, the inner surface of the cavities has at least a partially defined surface roughness. In particular, the corresponding inner surface is such that it forms at least the bonding surface and thus has a defined surface roughness in the area of ​​the bonding surface. Preferably, the entire inner surface has a defined surface roughness. It is preferred that the surface roughness of the inside of the cavities has an arithmetic mean roughness value Ra of >0 to 30 µm. Particularly preferred is an arithmetic mean roughness value Ra of >0 to 10 µm, preferably 0.5 to 5 µm, particularly preferably 1 to 4 µm, and further particularly preferably 2 to 3 µm.

[0018] The arithmetic mean roughness Ra of the inside of the cavity may preferably have values ​​as described above with reference to the surface of the inner part of the artificial tooth element.

[0019] In particular, to further improve the adhesive bond between the artificial tooth element and the prosthesis, it is preferred that the arithmetic mean roughness of the upper surface of the cavity is ± 50% of the arithmetic mean roughness of the surface of the inner part of the artificial tooth element.

[0020] The individual cavities are preferably designed, with respect to the insertion direction of the corresponding artificial tooth element into the denture base, such that the cavities are free of undercuts. This allows for easy arrangement of the artificial tooth elements in the corresponding denture base.

[0021] Preferably, the individual cavities of the denture base are designed to be complementary to the respective inner part of the artificial tooth element to be inserted. This creates a gap of constant width between each cavity and the inner part of the corresponding tooth element. This ensures secure fixation of the artificial tooth element in the denture base. Furthermore, the correspondence between the actual prosthesis and the planned virtual prosthesis is very high, so that the end user has to make very few adjustments. In particular, the occlusal plane and function correspond very precisely to the plan and require only minimal further adjustments, if any.

[0022] In a particularly preferred design of the denture base, the cavity has a minimum inner radius that is equal to or greater than the minimum outer radius of the inner part of the artificial tooth element. For example, if the inner part of the artificial tooth element has an outer radius of at least 0.6 mm or more, the cavity will exclusively have radii that are at least 0.6 mm or greater. This has the advantage that tools such as milling cutters with a corresponding machining radius can be used to create the cavities. For a radius of at least 0.6 mm, a milling cutter with a diameter of 1.2 mm can be used. Smaller milling cutters would have to be used to create smaller radii. Using smaller milling cutters or corresponding tools leads to longer cavity creation times and also to shorter tool life.It is therefore further preferred that the minimum inner radius of the cavity is in particular equal to or greater than 1.0 mm and especially preferably equal to or greater than 1.25 mm.

[0023] Particularly when using asymmetrical, especially non-rotationally symmetrical, artificial tooth elements, the cavities are also designed accordingly asymmetrically and, in a preferred embodiment, non-rotationally symmetrically. This has the significant advantage that a clear and unambiguous assignment between the respective artificial tooth element and the corresponding cavity, as well as a clear and unambiguous definition of the position of the corresponding tooth element within the cavity, are ensured.

[0024] It is therefore particularly advantageous if all cavities have a different shape, ensuring a clear match between the artificial tooth element and the cavity. This eliminates the possibility of incorrect insertion.

[0025] Furthermore, it is preferred that the cavities are designed in such a way, in particular have a depth such that an inserted artificial tooth element has a defined tooth height.

[0026] Furthermore, it is particularly preferred for aesthetic reasons that the virtual gingival line of the artificial tooth element coincides at least partially, and in particular completely, with the cavity edge in the inserted state, or that the two edges completely overlap.

[0027] A particularly suitable method for manufacturing a denture base and artificial tooth elements is described in WO 2018 / 036853.

[0028] The invention is explained in more detail below with reference to a preferred embodiment and the accompanying drawings.

[0029] They show: Fig. 1 a schematic perspective side view of an artificial tooth element according to the invention, Fig. 2 a schematic perspective rear view of an artificial tooth element according to the invention, Fig. 3 a schematic top view of a cavity in a denture base, Fig. 4 a schematic sectional view of a tooth element inserted into the cavity base and Fig. 5 a perspective view of a denture base with partially inserted artificial tooth elements.

[0030] At the one in the Figures 1 and 2In the illustrated example of a tooth element, which is an incisor, the virtual gingival line 10 is shown. The artificial tooth element shown as an example has an outer part 12 and an inner part 14. The outer part 12 is separated from the inner part 14 by the virtual gingival line 10. When the artificial tooth element is inserted into the denture base, the outer part 12 is located outside the denture base and is therefore visible. The inner part 14 is located inside the denture base when inserted and is therefore not visible. A surface 11 defined by the inner part 14, which extends to the virtual gingival line 10, has the surface roughness defined according to the invention.

[0031] The virtual gingival line lies within the undercut-free area. The undercut-free area is defined by line 16. Line 16 defines the boundary of the undercut-free area in the insertion direction. Figure 1 Below line 16, with respect to the insertion direction (arrows 17) into the prosthesis base, there is no further undercut. Above line 16, an undercut is made.

[0032] The line 16, which is located within the outer part 12 with respect to the virtual gingival line 10 or has a distance from the virtual gingival line 10, can further define a boundary of the surface 11 with a defined roughness. In a preferred embodiment, the surface 11 with defined roughness thus includes not only the surface in the area of ​​the inner part 14, but extends into the outer part in the direction of or up to the line 16.

[0033] A prosthetic base 20 ( Fig. 3The device has a cavity 22. This cavity is bounded by a cavity edge 24. An inner surface 25 of the cavity 22 preferably extends to the cavity edge 24. The inner surface 25 has a defined surface roughness.

[0034] Since it is particularly preferred that the inner part 14 of the tooth element be inserted in a direction 26 ( Fig. 4 Since the tooth elements in the cavities 22 have no undercuts, simple assembly or attachment, i.e., in particular insertion and bonding into the cavities 22, is possible. The cavities 22 also have no undercuts in the corresponding insertion direction 26. The insertion direction 26 runs essentially perpendicular to the denture base. If the denture were positioned in the patient's oral cavity, the insertion direction would run essentially vertically.

[0035] The cavity 22 is designed to be complementary to the inner part, thus ensuring a precise positioning of the tooth element within the cavity 22. Furthermore, a complementary design of the inner part 14 and the cavity 22 allows for the creation of an adhesive gap 28, if required. Fig. 4 ) can be realized, which has a constant width across its entire surface. Therefore, the volume of the adhesive gap and thus the required amount of adhesive are also precisely known.

[0036] In Fig. 4 In the diagram, in which the tooth element and the prosthesis base 20 are shown in section, the virtual gingival line 10 is also shown. The part of the virtual gingival line 10 shown as a solid line runs in front of the drawing plane relative to the section surface of the tooth element, and the part shown as a dashed line runs behind the drawing plane.

[0037] For the complete fabrication of a prosthesis, several cavities 22 are provided in the prosthesis base 20 ( Fig. 5 For example, a defined amount of adhesive is first applied to each cavity, and then the corresponding tooth elements are inserted into the cavities 22 in the insertion direction 26. With the tooth elements inserted, the cavity edge 24 and the virtual gingival line 10 preferably lie on top of each other. Due to the defined surface roughness of the surface 11 of the inner part 14 of the tooth element 12 and the defined surface roughness 25 of the cavity 22, a stable and very strong bond can be established.

Claims

1. An artificial tooth element for direct insertion into a cavity (22) of a prosthesis base (20), comprising an outer part (12) visible in the inserted state, and an inner part (14) not visible in the inserted state, wherein the inner part (14) comprises a defined surface roughness at least in part, characterized in that the surface roughness has an arithmetic average roughness value Ra of 1 to 4 µm.

2. The artificial tooth element according to claim 1, characterized in that the inner part (14) has a defined surface roughness in the region of a bonding surface (11).

3. The artificial tooth element according to claim 1 or 2, characterized in that the inner part (14) has a defined surface roughness across the entire surface (11).

4. The artificial tooth element according to any one of claims 1-3, characterized in that the surface roughness has an arithmetic average roughness value Ra of 2 to 3 µm.

5. A prosthesis with a prosthesis base having a plurality of cavities in each of which an artificial tooth element according to any one of claims 1-4 is inserted.

6. The prosthesis according to claim 5, characterized in that the cavities (22) have an inner surface (25) which at least in part has a defined surface roughness.

7. The prosthesis according to claim 6, characterized in that the inner surface (25) has a defined surface roughness in the region of a bonding surface.

8. The prosthesis according to claim 6 or 7, characterized in that the entire inner surface (25) has a defined surface roughness.

9. The prosthesis according to any one of claims 5-8, characterized in that the surface roughness of the inner side has an arithmetic average roughness value Ra of >0 to 30 µm, preferably >0 to 10 µm, more preferred 0.5 to 5 µm, particularly preferred 1 to 4 µm, and most preferred 2 to 3 µm.

10. The prosthesis according to any one of claims 5-9, characterized in that the cavities (22) are free from undercuts with respect to a direction of insertion (26) in which the tooth element is inserted into the prosthesis base (20).

11. The prosthesis according to any one of claims 5-10, characterized in that the cavities (22) are formed complementarily to the inner parts (14) of the respective artificial tooth element so that a gap of in particular constant width is formed between the cavities (22) and the inner part of the associated tooth elements.

12. The prosthesis according to any one of claims 5-11, characterized in that the cavities (22) are formed asymmetrically, in particular not rotationally symmetrically, and / or all cavities (22) have different shapes so that an unambiguous association between the artificial tooth element and the cavity (22) exists.

13. The prosthesis according to any one of claims 5-12, characterized in that the cavities (22) are formed such that an inserted artificial tooth element has a defined tooth height.

14. The prosthesis according to any one of claims 5-13, characterized in that the cavities (22) have a minimum inner radius that is equal to or greater than the minimum outer radius of the inner part (14) of the artificial tooth element to be inserted into the cavity.