System and Dental Implant for Reducing Losses of Dental Implants or Dental Prostheses

Abstract

A dental implant includes an insertion portion which extends along an implant axis, and a coronal projection for receiving an abutment having a dental prosthesis formed thereon, which can be mounted on the dental implant with a screw. The insertion portion includes a coronal region and an apical region. The coronal projection extends from the coronal region of the insertion portion in the coronal direction and along a prosthesis axis. The coronal projection and the insertion portion are integrally connected in one piece. The prosthesis axis and the implant axis are inclined towards each other, and the abutment having the dental prosthesis formed thereon is attachable to the dental implant with only one screwing operation in the direction of the prosthesis axis.

Claims

1. A dental implant having: an insertion portion which extends along an implant axis, and a coronal projection for receiving an abutment having a dental prosthesis formed thereon, which can be mounted on the dental implant with a screw, wherein said insertion portion comprises a coronal region and an apical region, and wherein the coronal projection extends from the coronal region of the insertion portion in the coronal direction and along a prosthesis axis, wherein said coronal projection and said insertion portion are integrally connected in one piece, wherein the prosthesis axis and the implant axis are inclined towards each other, and the abutment having said dental prosthesis formed thereon is attachable to the dental implant with only one screwing operation in the direction of the prosthesis axis.

2. The dental implant of claim 1, wherein the dental implant is made solid in the coronal region.

3. The dental implant of claim 1, wherein in use, the insertion portion is to be inserted into the jawbone of a patient in such a manner that apposition of bone in the coronal region is enabled.

4. The dental implant of claim 1, wherein said coronal region is rotationally symmetric around the prosthesis axis and tapers in coronal direction, thereby enabling subtractive removal of a an annular material region in the coronal region using a milling cutter that rotates about the prosthesis axis.

5. The dental implant of claim 1, wherein in use, the insertion portion is to be inserted into the jawbone of a patient in such a manner that apposition of bone in the coronal region is enabled, and wherein said coronal region is rotationally symmetric around the prosthesis axis and tapers in coronal direction, thereby enabling subtractive removal of an annular material region in the coronal region using a milling cutter that rotates about the prosthesis axis.

6. The dental implant of claim 5, wherein the dental implant is made solid in the coronal portion.

7. The dental implant of claim 1, wherein the prosthesis axis and the implant axis are inclined towards each other at an angle α in the range 0°<α≤45°.

8. The dental implant according to claim 6, in which the inclination of the peripheral surface of the dental implant in the coronal region with reference to the prosthesis axis is in some sections is between 35° and 55°.

9. The dental implant according to claim 1, in which the inclination of the peripheral surface of the dental implant in the coronal region with reference to the prosthesis axis is in some sections is between 0° and 5°.

10. The dental implant according to claim 1, in which the coronal projection is conical and has a cone angle of less than 11°.

11. The dental implant according to claim 10, in which the coronal projection has a cone angle of between 6° and 10°.

12. The dental implant according to claim 1, in which in at least some sections the coronal projection has a circular or elliptical cross section.

13. The dental implant according to claim 1, in which the dental implant has a shoulder at the coronal end of the insertion portion.

14. A system comprising: a dental implant according to claim 1; and a device for intra-oral subtractive machining of the inserted dental implant, wherein the device comprises: a connection with which the device inside the oral cavity of a patient can be connected to the implant, and a subtractive machining unit, with which dental implant material can be removed from the surface of the coronal region.

15. The system of claim 14, wherein said subtractive machining unit is a milling cutter.

16. The system of claim 15, further comprising a guide part that can be placed on top of the abutment, and wherein said milling cutter comprises an inner recess matching said guide part.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Additional advantages and features of the invention are obtained from the description of the following figures, in which the same parts are labelled with the same reference number.

[0051] The drawings show:

[0052] FIG. 1 a dental implant, which forms a part of a system according to the invention,

[0053] FIG. 2A a longitudinal cross-section of the implant in FIG. 1,

[0054] FIG. 2B a cross-sectional detail of the replacement ring in FIG. 2A,

[0055] FIG. 3 a replacement ring which is used in the system according to the invention of FIGS. 2A-2B, in a sectional view (top) and in plan view (bottom),

[0056] FIG. 4 a section through a replacement ring of a system according to the invention in accordance with a second embodiment,

[0057] FIG. 5 a section through a replacement ring of a system according to the invention in accordance with a third embodiment,

[0058] FIG. 6 an implant for an external implant-abutment connection (a) and an implant for an internal implant-abutment connection (b), and

[0059] FIG. 7 a dental implant according to the invention, in which the prosthesis axis and the implant axis are inclined towards each other.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0060] FIG. 1 shows a dental implant 10 that is suitable for use in a system according to the invention and is attached to an abutment 12 using a screw 14. The dental implant 10 comprises an insertion portion 16, which in turn comprises a coronal region 18 and an apical region 20. At the coronal end of the insertion portion 16 a shoulder 22 is located, from which an external cone 24 extends in the coronal direction along a prosthesis axis P. In the implant 10 of FIG. 1 the prosthesis axis P coincides with an implant axis I, which runs along the insertion portion 16 through the centre thereof. Recesses 27 are provided on the side of the external cone 24, which are used to secure a rotational position of the abutment 12.

[0061] When providing a patient with the implant 10, the insertion portion 16 is inserted into the jaw bone of the patient, wherein the insertion portion 16 is screwed into the bone by means of a thread (not shown). As shown in FIG. 1, the apical region 20 can taper in the apical direction (“downwards” in FIG. 1). As can be seen from FIG. 1, in the coronal region 18 the outer peripheral surface 26 of the dental implant 10 is inclined with respect to the implant axis I by the angle γ, so that the coronal region 18 tapers in the coronal direction (“upwards” in FIG. 1). This tapering in the coronal direction allows the apposition of a thicker layer of bone onto the implant at the coronal end of the insertion portion 16, which enables the incidence of peri-implantitis to be avoided. By way of deviation from the not true-to-scale drawing of FIG. 1, the angle γ can have a value of 45°, which facilitates a particularly good bone augmentation. It is explained below that in some sections an angle of γ=1.5° can also be advantageous.

[0062] The cone angle β in a preferred embodiment is 8°. This means that the tapering connection between the correspondingly shaped abutment 12 and the external cone 24 is self-locking, i.e. on account of a frictional connection is secured against twisting, and to a certain extent against being pulled apart. Such a tapered connection with a cone angle β of less than 11° is self-locking and also bacteria-proof, so that the risk of bacteria accumulation between the abutment 12 and the implant 10 is low.

[0063] Preferably, the external cone 24 has a circular cross-section in a cut perpendicular to the prosthesis axis P. In contrast to a cross-section with a hexagonal profile or polygonal profile, the circular cross section avoids any play, for example when a rotational force acts on the abutment 12. This allows the anti-bacterial quality of the implant-abutment connection to be further improved and also prevents the screw 14 from becoming loose over time.

[0064] The shoulder 22 offers the advantage that, on the one hand enough space is available laterally, that is to say perpendicular to the implant axis I, to remove material from the implant 10 in the coronal region 18 and thus at the same time to remove a contaminated surface in the coronal region 18. On the other hand, due to the shoulder 22 a space exists between the apical end of the abutment 12 and the surrounding bone, which is adsorbed at the side of the peripheral surface of the implant 26. Due to this offset (so-called platform switching), the risk of peri-implantitis can be further reduced, because due to the shoulder 22 any bacterial colonization occurring in the implant-abutment connection does not directly adjoin the surrounding bone tissue and the treated implant surface for bone apposition.

[0065] In a preferred embodiment, the external cone 24 has a length of between 1.5 mm and 3.5 mm, for example 2.5 mm, the coronal region 18 has an extension of between 2 mm and 4 mm, for example, 3 mm, in the direction of the implant axis I and the external cone 24 has a diameter between 1.7 mm and 3.7 mm, for example, 2.7 mm, at the apical end at the level of the shoulder 22. The width B of the shoulder is 22 in a preferred embodiment is between 0.2 mm and 2 mm, for example, 1.5 mm.

[0066] In all embodiments according to the invention the implant 10 and/or the replacement ring 28 can be made of titanium.

[0067] FIGS. 2A-2B show a system according to the invention in accordance with a first embodiment with the implant 10 of FIG. 1 and a replacement ring 28. FIG. 2A shows a longitudinal section through the replacement ring 28 along a central axis M of the replacement ring. From FIG. 2B it can be seen that both the outer peripheral surface 30 of the replacement ring 28 and the inner peripheral surface 32 of the of the replacement ring 28 are inclined with respect to the central axis M, namely at an angle δ or ρ. This reduces both the outer and the inner diameter of the replacement ring 28 in the direction of a coronal side 34 of the replacement ring 28, which is located opposite to an apical side 36 of the replacement ring 28.

[0068] In the embodiment of FIGS. 2A-2B the region of material of the implant 10 to be replaced is shown hatched. It is important to note that, as in FIG. 1, the representation of the implant 10 in FIG. 2 is a longitudinal section through the implant along the implant axis I. The implant 10 can be rotationally symmetrical or substantially rotationally symmetrical about the implant axis I and the prosthesis axis P. A coronal region 18 which is rotationally symmetrical about the prosthesis axis P, offers the advantage that it can be easily milled using a milling cutter that rotates about the prosthesis axis P.

[0069] After the subtractive machining of the dental implant 10 the outer peripheral surface 30 of the dental implant 10 in the coronal region 18 preferably has a shape or contour that conforms to the inner peripheral surface 32 of the associated replacement ring 28. This makes it possible with the preferred inclination of the peripheral surfaces 30 and 32 with respect to the implant axis I, or to the central axis M, to mount the replacement ring 28 on to the subtractively machined implant 10 in the coronal to apical direction. With an angle of 1.5° between the peripheral surfaces 30, 32 and the respective axes I, M, the connection between the subtractively machined implant and the mounted replacement ring 28 can be force-fitting or friction-fitting, in such a way that an additional screw connection is not required.

[0070] The shape and the contour of the outer peripheral surface 30 of the replacement ring can conform to the shape and the contour of the peripheral surface 26 of the unmachined implant 10, but this is not absolutely required.

[0071] In order to restore the condition of the bacteria-free, unmachined implant 10 after the insertion, the replacement ring 28 preferably has an outer surface whose structure and texture correspond to that of the original implant surface.

[0072] At the top of FIG. 3 the replacement ring 28 of the system of FIGS. 2A-2B is again represented as a longitudinal section along the central axis M. At the bottom of FIG. 3 and FIG. 4, a plan view of the replacement ring 28 is shown along the central axis M. Even if in the embodiment of FIG. 3 the cross-sections through the peripheral lines 32 and 30 of the replacement ring 28 are both circular, it is important to note that the cross-sectional lines through the peripheral surfaces 32 and 30 can also have other closed curves, for example that of a polygonal or hexagonal profile, or other non-symmetrical curves. The same is true for the implant, which does not necessarily have to be rotationally symmetrical.

[0073] FIGS. 4 and 5 show replacement rings 328 and 428, which each belong to a system according to the invention of a second embodiment and a third embodiment. In the replacement ring 328 of FIG. 4 the outer peripheral surface 30 is inclined by 45° with respect to the central axis M, to enable good bone apposition and to prevent peri-implantitis. The inner peripheral surface of the 32, in a coronal and in an apical region (respectively above and below the dashed lines), is also inclined by 45° and thus parallel to the outer peripheral surface 30. In an intermediate region the inner peripheral surface 32 is inclined by 1.5° with respect to the central axis M to facilitate a force-fitting connection, which does not require a screw connection, between the correspondingly subtractively machined implant 10 and the replacement ring 328.

[0074] In the replacement ring 428 of FIG. 5 the profile of the inner peripheral surface 32 conforms to the profile of the inner peripheral surface 32 of the replacement ring 328 of FIG. 4. The profile of the outer peripheral surface 30 of the replacement ring 428 of FIG. 5 is parallel to the profile of the inner peripheral surface 32 of the same replacement ring. As a result, the thickness D of the replacement ring 428 is constant in the direction of the central axis M. If the profile of the peripheral surface 26 of the implant 10 corresponds to the profile of the peripheral surface 30 of the replacement ring 428, then the material removal can be effected uniformly along the implant axis I, i.e. the thickness of the material region removed is constant in the direction of the implant axis I.

[0075] In FIG. 6 the implant 10 of FIGS. 1 and 2, which has an external cone 24, is compared with an implant no, which has an internal cone 40 for an internal tapered connection.

[0076] Compared to an internal tapered connection, an external tapered connection with the cone 24 offers the advantage that the implant 10 can be made more solid and stable than the implant no. Because of the solid design of the implant 10, tensions can be avoided during the fitting of a prosthesis tooth, in particular in the coronal region 18 of the insertion portion 16, which can reduce the stress on the surrounding tissue. The risk of an incidence of peri-implantitis and a resulting loss of the implant can therefore be reduced by means of the external cone 24. In addition, with the more solid implant 10 the risk of an implant fracture is also lower. There is also more material available for a subtractive removal, in which there is no risk that a critical wall thickness of the implant will be undershot.

[0077] Even if the implant 10 of FIG. 6 (a) is preferred over the implant no of FIG. 6 (b) for use within a system according to the invention, it should be noted that the implant no can also be part of a system according to the invention.

[0078] FIG. 7 shows a dental implant 210 according to the invention, having an external cone 124 which extends along a prosthesis axis P that is inclined at an angle α with respect to the implant axis I. The angle α has a value in the range 0°<α≤45°. When fitting a dental prosthesis it often happens that the prosthesis axis P, which extends through the centre of the dental prosthesis and along which the screw connection of the dental prosthesis is made, does not coincide with the implant axis I.

[0079] In the prior art therefore, angled abutments or adapter fittings are generally used, for example when fitting an implant no, as shown in FIG. 6 (b). In a first step the abutment or the adapter piece is screwed together with the inserted implant in the direction of the implant axis I. In a second step the dental prosthesis is screwed along the prosthesis axis P which is inclined with respect to the implant axis I.

[0080] The implant 210 of FIG. 7 offers the advantage that only one screwing operation is required, namely along the prosthesis axis P, and the second connection between the implant and the abutment or the connection part can be dispensed with, even if the prosthesis axis P and the implant axis I are divergent. This makes it possible to form the dental prosthesis directly on the abutment and to cement it on the abutment even before the treatment session. This unit consisting of the dental prosthesis and abutment can then be mounted on the inserted implant 210 with only one screwing operation, without a cementing operation or other connection having to be carried out in the oral cavity of the patient, and thus reducing the risk of peri-implantitis and loss of the dental prosthesis and implant.

[0081] Since the dental implant 210 of FIG. 7 is solid in the same way as the dental implant 10, it has the same corresponding advantages as were described earlier in relation to FIG. 6a, thus further reducing the number of implant losses and the losses of implant-borne dental prostheses. The dental implant 210 can also be made from titanium, as is the dental implant 10.

[0082] It should be pointed out that the embodiments described above are purely examples of the present invention, which is not limited thereto. The previously described features can be meaningful in any combination. The scope of the present invention is derived solely from the claims.

LIST OF REFERENCE NUMERALS

[0083] 10, 110, 210 dental implant [0084] 12 abutment [0085] 14 screw [0086] 16 insertion portion [0087] 18 coronal region [0088] 20 apical region [0089] 22 shoulder [0090] 24, 124 external cone [0091] 26 peripheral surface of the implant. [0092] 28, 328, 428 replacement ring [0093] 30 outer peripheral surface of the replacement ring [0094] 32 inner peripheral surface of the replacement ring [0095] 34 coronal side [0096] 36 apical side [0097] 38 peripheral surface of the implant after subtractive machining step [0098] 40 internal cone [0099] P prosthesis axis [0100] I implant axis [0101] M central axis