OCCLUSAL SCREW, DENTAL IMPLANT SYSTEM AND SET

Abstract

An occlusal screw for a two-part dental implant system with an anchoring part and an abutment includes a screw head and a screw shank. The screw head apically forms a screw stop. The occlusal screw consists of a ceramic material and has an engagement portion with an outer structure that is not rotationally symmetrical about the screw axis, is cylindrical or conical at least in regions and is suitable for interacting with a corresponding inner structure in a distal recess of a screwing tool, in order to couple the occlusal screw onto the screwing tool in a rotationally fixed manner. A design concerning which the engagement portion occlusally includes a cylindrical region and apically thereof a clamping region, which continuously widens in the apical direction, is particularly advantageous. The clamping region can be for example conical.

Claims

1. An occlusal screw for a ceramic implant system, comprising a screw head and a screw shank, wherein the screw shank comprises a screw thread which defines a screw axis and is envisaged to engage through an opening of an abutment of the implant system which is continuous in the axial direction, into an inner thread in a recess of an anchoring part of the implant system and wherein the screw head apically forms a screw stop, wherein the occlusal screw consists of a ceramic material and comprises an engagement portion which has an outer structure which is not rotationally symmetrical about the screw axis, is cylindrical or conical at least in regions and is suitable for interacting with a corresponding inner structure in a distal recess of a screwing tool, in order to couple the occlusal screw onto the screwing tool in a rotationally fixed manner.

2. The occlusal screw according to claim 1, wherein the engagement portion at least regionally is cylindrical with respect to the screw axis.

3. The occlusal screw according to claim 1, wherein the engagement portion comprises a cylindrical region and apically of this a clamping region which continuously widens in the apical direction.

4. The occlusal screw according to claim 3, wherein the clamping region is conical.

5. The occlusal screw according to claim 4, wherein the clamping region has a cone angle of between 7° and 20°.

6. The occlusal screw according to claim 3, wherein a concave region is formed apically of the clamping region.

7. The occlusal screw according to claim 1, wherein the stop (66) is formed by a conical stop region with a cone angle of more than 90°.

8. The occlusal screw according to claim 7, wherein the conical stop region merges into the screw shank via a fillet.

9. The occlusal screw according to claim 1, wherein the engagement portion comprises the structure of a regular hexagon.

10. A dental implant system comprising: an anchoring part for anchoring in bone tissue, wherein the anchoring part is manufactured of a ceramic material and defines an axis, an abutment of a ceramic material, wherein the anchoring part comprises a recess which is open towards a coronal end, for an engagement of a fastening post of the abutment, an occlusal screw according to claim 1, wherein the abutment comprises an opening which is continuous in the axial direction and into which the occlusal screw can be inserted, wherein the occlusal screw is configured, for fastening the abutment to the anchoring part, to engage into an inner thread which is formed on the anchoring part in the recess, and wherein a shoulder that is formed in the coronal direction is present in the opening, said shoulder together with the screw stop forming a stop on inserting the screw into the opening.

11. The system according to claim 10, wherein the anchoring part comprises an outer thread whose threaded axis corresponds to the axis.

12. The system according to claim 10, wherein the recess forms a conical support region, into which a conical support portion of the abutment engages.

13. The system according to claim 10, wherein the recess comprises an inner structure region with an inner structure which forms an insert geometry for interaction with a corresponding rotation lock structure of the abutment.

14. The system according to claim 12, wherein the recess from coronally to apically firstly forms the support region, then the inner structure region and then an inner threaded region.

15. The system according to claim 10, wherein the anchoring part is designed as a bone-level anchoring part.

16. The system according to claim 10, further comprising a screwing tool with an engagement region which forms an opening with an inner structure which is matched to the outer contour of the engagement portion, in order, given the engagement portion inserted into the opening, to rotate the occlusal screw by way of rotating the screwing tool about the screw axis.

17. A set, comprising an occlusal screw according to claim 1 as well as a screwing tool with an engagement region which forms an opening with an inner structure which is matched to the outer contour of the engagement position, in order, given the engagement portion inserted into the opening, to rotate the occlusal screw by way of rotating the screwing tool about the screw axis.

18. The set according to claim 17, wherein the engagement portion comprises a cylindrical region and apically of this a clamping region which continuously widens in the apical direction, wherein the engagement region comprises a part-region, in which the inner structure is cylindrical, and wherein an axial extension of the part region with the cylindrical inner structure is larger than an axial extension of the cylindrical region.

19. The set according to claim 17, wherein the occlusal screw apically of the engagement portion forms a widening, and wherein an outer diameter in the region of the widening corresponds essentially to an outer diameter of the engagement region of the screwing tool.

20. The set according to claim 17, wherein the screwing tool comprises a predetermined breakage location, at which, when the screwing tool is engaged with the occlusal screw, given the application of an increasing torque on an occlusal end of the screwing tool, the screwing tool breaks without the occlusal screw breaking.

21. The system according to claim 16, wherein the engagement portion comprises a cylindrical region and apically of this a clamping region which continuously widens in the apical direction, wherein the engagement region comprises a part-region, in which the inner structure is cylindrical, and wherein an axial extension of the part region with the cylindrical inner structure is larger than an axial extension of the cylindrical region.

22. The system according to claim 16, wherein the occlusal screw apically of the engagement portion forms a widening, and wherein an outer diameter in the region of the widening corresponds essentially to an outer diameter of the engagement region of the screwing tool.

23. The system according to claim 16, wherein the screwing tool comprises a predetermined breakage location, at which, when the screwing tool is engaged with the occlusal screw, given the application of an increasing torque on an occlusal end of the screwing tool, the screwing tool breaks without the occlusal screw breaking.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The subject-matter of the invention is hereinafter explained in more detail by way of preferred embodiment examples which are represented in the accompanying drawings. What is shown in scales which are partly different from figure to figure are:

[0029] FIG. 1 an implant system with an anchoring part, abutment, occlusal screw and screwing tool, in one view,

[0030] FIG. 2 a sectioned representation (parallel to the axis, sectioned along the plane A-A) of the system according to FIG. 1;

[0031] FIG. 3 a view corresponding to FIG. 1 of the system in the put-together state;

[0032] FIG. 4 a sectioned representation (parallel to the axis, sectioned along the plane B-B) of the arrangement according to FIG. 3;

[0033] FIG. 5 a representation of the occlusal screw;

[0034] FIG. 6 a detail of the occlusal screw;

[0035] FIG. 7 a sectioned representation of a suitable screwing tool; and

[0036] FIG. 8 a detail of the screwing tool of FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION

[0037] In the figures, the same reference numerals denote the same or analogous parts.

[0038] The dental implant (anchoring part 1) which amongst others is represented in FIGS. 1-4, has an outer thread 11 that extends almost over the entire length, almost up to the coronal end and that defines an axis 100. The anchoring part 1 has a shape that tapers slightly in the apical direction, so that in cross section along a plane parallel to the axis 100 as a whole with the exception of the thread furrows and apical chip grooves 12 it is curved in a slightly convex manner and, as a whole, merges from a coronally roughly cylindrical shape into an apically tapering shape. The outer thread 11 has a non-constant thread depth and is designed for example in a self-cutting manner.

[0039] A recess 13 into which a fastening post 21 of an abutment 2 projects in the finished implanted state of the implant system is open to the coronal end. The recess forms a coronal support region 18, apically thereof an insert geometry region 19 and apically of this an inner threaded region 17. The support region 18 as a whole has a conical course with a diameter that widens slightly in the coronal direction. The recess forms an insert geometry in the insert geometry region 19 by way of it running about the axis 100 in a manner that is not rotationally symmetrical. In the represented embodiment example, an equilateral hexagon with rounded corners is formed in cross section along a plane perpendicular to the axis 100, wherein it is cylindrical in the sense that it has a constant cross section along the axis. The inner threaded region is provided with an inner thread which is matched to a screw thread of the occlusal screw.

[0040] In the represented embodiment example, the anchoring part is a bone-level implant, with regard to which the implant shoulder 10 with a circular edge which terminates the inner connection between the anchoring part 1 and the abutment 2 is at bone level. The invention, however, can also be applied to other two-part implant systems, specifically to tissue level implants, concerning which a transgingival region, which is widened, for example, in a tulip-like manner, is formed on the anchoring part coronally of the enossal part with the thread.

[0041] Apart from the fastening post 21, the abutment 2 includes a coronal post 23 for fastening a superstructure. Apically of this there is formed a transgingival region 22, which is adapted, for example, to the expected course of the gingiva. The shapes of such a transgingival region 22 as well as of the post 23—here angled with respect to the axis 100 and drawn with an optional flattening—including its angle to the fastening post and thus to the axis 100 are adapted to specific requirements and depend on where the implant is placed or has been placed in the jaw. In particular, an implantation set with at least one anchoring part can comprise several different abutments for different implant situations.

[0042] The fastening post 21 forms a support portion that, in its shape, is matched to the support region 18 and apically of this, a rotation lock structure 27. The rotation lock structure 27 has a hexagonal shape, likewise with rounded edges.

[0043] The abutment has an axially continuous opening 29 for the occlusal screw. Furthermore, this opening forms a shoulder 24 for the head of the occlusal screw. Furthermore, in the represented embodiment example an optional abutment inner thread 25 for a so-called retrieval tool (a tool for removing the abutment) is present on the opening.

[0044] The occlusal screw 6 has a shank 61 with the outer thread 62 that is matched to the inner thread of the anchoring part, as well as a screw head 65. This head forms an engagement portion 64 and apically of this a widening 63 and furthermore a screw stop 66 in the apical direction. The engagement portion 64 is shaped out as an outer structure for the interaction with a corresponding inner structure of the screwing tool. In the represented embodiment example, the engagement portion has a hexagon structure.

[0045] The outer thread 62 of the occlusal screw defines a screw axis 101 (see FIG. 5 hereinafter). In the represented embodiment example, this coincides with the axis 100 of the implant. This per se is not a necessity. Configurations in which the screw axis and accordingly also the axially continuous opening 29 in the abutment as well as the inner threaded region 17 are slightly offset and/or slightly inclined to the axis 100 of the implant are also conceivable.

[0046] The screw tool 7 at one end forms an engagement region 71 which is matched to the engagement portion 64. At the opposite (coronal/proximal) end it includes an adapter head 72 for a screw instrument, for example a screw instrument (ratchet) for applying a defined, e.g., settable torque.

[0047] A further optional feature of the screwing tool is likewise visible in FIG. 1-4. The screwing tool along its course forms a necking 73, which forms a predetermined breakage location. The torque for breaking the screwing tool at the predetermined breakage location is significantly smaller than the torque for breaking the occlusal screw. For example, the predetermined breakage location is to break at a value between approx. 15-25 Ncm, while the screw breaks at a torque which for example is at least 5 Ncm larger than this value. In particular, the torque for breaking the screw can be at least 20% or at least 30% higher than that of the predetermined breakage location.

[0048] The setting of the strength of the predetermined breakage location can be effected, for example, in a very simple manner via the material thickness at the location of the necking and can include an experimental determining of the torque causing a breakage as a function of the cross-sectional area at the location of the lowest material thickness. The maximal torque that can be applied to the occlusal screw can be determined experimentally, too.

[0049] FIG. 5 shows the occlusal screw 6 in a view with an outer thread 62, which is merely represented schematically, and FIG. 6 shows the region, which is circled in FIG. 5 in an enlarged and somewhat more detailed manner. It is particularly shown in FIG. 6 than one can see that the engagement portion 64 apart from a cylindrical (i.e. translation-symmetrical along the axis) region 41 includes apically thereof a clamping region 42 that continuously widens in the apical direction. The cylindrical region 41 has an outer hexagonal shape, i.e., it is hexagonal with rounded corners in a cross section perpendicularly to the axis. The clamping region as a rule has the same symmetry as the cylindrical region, i.e., in the present example it is likewise hexagonal in cross section.

[0050] In the represented embodiment example, the clamping region, which is subsequent to the cylindrical region 41, is conical, with a cone angle (cone angle/cone opening angle, corresponding to double the angle to the axis) of approx 14°. Generally, in the case of a conical clamping region it is preferable for the cone angle to be between 7° and 20°, in particular between 10° and 18°.

[0051] In the represented embodiment example, the clamping region merges via a fillet into a shoulder, which is formed in the coronal direction and which is formed by the widening, i.e., a concave region 43 is formed apically of the clamping region.

[0052] A further detail of preferred embodiments can be seen in FIG. 6 at the lower side of the widening 63. The screw stop 66 is not formed by a straight shoulder but rather includes a conical stop region 67 with a large cone angle of above 90°. Subsequent to this apically, the occlusal screw 6 forms a further fillet 68. The shoulder 24 of the continuous opening 29 of the abutment can likewise be formed at a non-right angle to the screw axis in accordance with the conical stop region 67, which can be seen in FIG. 2.

[0053] It has been found that the fillet 68 as well as the conicity of the stop region 67 contributes to the breaking strength of the ceramic occlusal screw.

[0054] The screwing tool is shown in section in FIG. 7. FIG. 8 shows the region that is circled in FIG. 7 in an enlarged manner. The engagement region is relatively thin-walled with an average (i.e. averaged over the peripheral direction) wall thickness of a mere approx. 0.3 mm. Preferably, the wall thickness is in a range of between 0.18 mm and 0.4 mm, in particular between 0.25 mm and 0.35 mm. The engagement region forms a hexagonal inner structure that is cylindrical, i.e., translationally symmetrical along the screw axis.

[0055] The axial extension d.sub.3 of the engagement region 71 (or in order to be more precise of its part region that includes a cylindrical inner structure 75) is larger than the axial extension d.sub.1 of the cylindrical region 41 and, for example, at least equally large as the cumulated axial extension d.sub.2 of the cylindrical region 41 and of the clamping region 42, so that it is not its engagement region 71 or the apical end 77 of its cylindrical part region, but its coronal end which forms a stop when the screwing tool is brought into engagement with the occlusal screw. This is effected by way of the peripheral inner edge 78 abutting at the clamping region 42 at the mouth of the opening 74, said opening being formed by the engagement region 71.