WO2008106988A1

WO2008106988A1 - Implant for screwing into bones

Info

Publication number: WO2008106988A1
Application number: PCT/EP2007/001812
Authority: WO
Inventors: Jürgen Siemonsmeier
Original assignee: Tissuedent Gmbh & Co. Kg
Priority date: 2007-03-02
Filing date: 2007-03-02
Publication date: 2008-09-12

Abstract

The invention relates to an implant (1) and/or a bone screw with at least one shank area (2) and at least one screw thread section for screwing into a bony structure, wherein the shank area (2) and/or the screw thread section has/have at least one recess (9) and/or at least one elevation. According to the invention, the recesses (9) are oriented in the opposite direction of screwing in, in the direction of the distal end (6). The longitudinal axis of the recesses (9) is thereby arranged approximately parallel to the thread pitch of the external thread which is not pictured here. The orientation of the recesses (9) according to the invention guarantees that the implant (1) cannot be loosened in the unscrewing direction, but is in addition secured, and that no bone material presses into the recesses (9) during screwing in.

Description

Implant for screwing into bone

Background of the invention

The invention relates to an implant and / or a bone screw having at least one shank region and at least one threaded section for screwing into a bony structure, wherein the shank region and / or the threaded section has / have at least one recess and / or at least one protrusion.

Implants or bone screws of the type mentioned are known from various fields of surgery or maxillofacial surgery and usually consist of a shaft region and a molded or attached to this head area. While the shaft region is introduced into the bone tissue with its apical end and serves to anchor the implant in the bone, a prosthesis or a dental crown replacement is attached to the head region, for example. The shaft region often consists of a porous material or a solid material perforated on its surface so that the bone tissue can grow into the pores to improve the fixation of the implant. The head region often has at its distal end an opening or attachment means in which or to which the prosthesis or an adapter provided therefor can be attached. In the distal opening of the head area, for example, there may be an internal thread into which a corresponding screw can be screwed. In daily dental or orthopedic surgical practice, the implant is placed as an anchoring module in the bone, ie screwed in, for example, by means of a self-tapping external thread, and then the enosis integration is awaited. To improve the integration into the bone tissue, the most varied surface structures or material structures for the shaft area have already been investigated. When anchoring the known implants with perforated surface in the bone, there is often the problem that the implant sits firmly in the same immediately after screwing into the bone, but after 4 to 8 weeks by the reconstruction of the bone tissue, especially in the direction of unwinding again loosens. However, this easing should be avoided as it is an important requirement of modern implants that they can be relieved as quickly as possible or immediately.

State of the art

From DE 33 15 329 C2, for example, a dental implant anchor is known, which has a cylindrical shaft region with a threaded portion and a perforated portion, which may also be identical. The threaded portion in turn has a self-tapping external thread for screwing the implant into the bone tissue, which can then grow through the perforations for permanent anchoring of the implant. However, this implant has the disadvantage that the perforations are milled virtually perpendicularly into the wall of the shaft region, so that the edges of the perforations form prominent retentions, which hinder screwing in of the implant. In addition, in this implant loosening of the implant in the direction of rotation can not be prevented.

From US Pat. No. 6,939,135 B2 a tooth root implant is known which consists of a head arranged at the distal end of the implant and a shaft connected in one piece with it. The cylindrical shaft has an external thread for screwing into the jawbone and vertically extending rows of radially outwardly extending outlet openings. These outlet openings are connected via a channel running centrally in the shaft to an opening at the distal end of the shaft, so that growth factors introduced through the opening can be introduced via the outlet openings into the bone structure surrounding the implant radially. However, this implant also has the disadvantage that the outlet openings are arranged perpendicular to the longitudinal axis of the shaft. If the known tooth screwed root implant into the bone, the outlet openings form significant retention, which complicates the insertion of the implant. In addition, when screwing in cell material pushes into the outlet openings, so that they clog and thus can no longer fulfill their actual function as access to the surrounding bone tissue. Furthermore, a loosening of the implant in the direction of rotation can not be prevented even with this implant.

From WO 2004/058091 A1, an implant is also known, which has an external thread in its shank region, the thread flanks of which are provided with grooves in order to enable coalescence with the bone tissue and thus to improve the retention of the implant in the bone. However, even this known implant has no means that could prevent a relaxation of the implant in the direction of rotation.

Summary of the invention

It is therefore an object of the invention to provide an implant and / or a bone screw of the type mentioned, with the or a loosening of the implant or the bone screw, in particular in the direction of unwinding, and the storage or preservation of inferior, hindering the healing process Cell material can be effectively avoided.

According to the invention the object is achieved by an implant and / or a bone screw of the type mentioned, in which the recess and / or elevation opposite to the screwing and at least approximately parallel to the thread pitch of the threaded portion is / are. The orientation of the recess and / or elevation along the thread pitch and opposite to the screwing the support of the implant or the bone screw in the bone is significantly improved and in particular a relaxation in the direction of rotation effectively avoided. Due to this special structuring of the surface, furthermore, there are none when the implant or the bone screw is screwed into the bony structure Retention before, which could complicate the insertion. The alignment of the recess and / or elevation rather leads opposite to the insertion direction to a significant resistance, so that an independent unscrewing or loosening of the implant or the bone screw, for example by a passive movement, prevents and thus the stability of the implant or the bone screw is increased in the bone. The solution according to the invention also has the advantage that no bone material can slide into the recess when screwing in the implant or the bone screw so that inferior cell material hindering the healing process is not stored or preserved at all. In this way, further, in the event that the recess is designed as an opening and should serve as access to the surrounding tissue, clogging of the access is avoided and thus ensures the freedom of the same.

In a particularly advantageous embodiment of the invention, it is provided that the recess is oriented such that the surface of the recess forms an angle of at least approximately 90 ° with the implant surface on the side facing the screwing-in direction. By this measure, on the one hand in the direction of rotation creates a sharp-edged structure, which opposes a loosening of the implant in the direction of twisting a clear resistance, and on the other hand forms an undercut, can grow into the cell material and thus by compression of the bone tissue in this area an additional fixation of the implant in the Ensures bone.

In a further particularly advantageous embodiment of the invention, it is provided that the recess is oriented such that the surface of the recess forms an angle of less than approximately 90 ° with the implant surface on the side remote from the screwing-in direction. By this measure it is avoided that there are retentions when screwing the implant, which could complicate an insertion of the implant in the bone. This effect can be enhanced by the fact that the surface of the recess is flattened on the side facing away from the screwing, convex and / or rounded at the transition to the implant surface. In a particularly advantageous embodiment of the invention is further provided that the survey is oriented such that the surface of the survey forms an angle smaller than about 90 ° on the side remote from the screwing with the implant surface. As a result, on the one hand, the implant surface is roughened in the direction of rotation in such a way that the implant can be prevented from loosening in the unwinding direction, and, on the other hand, there is an undercut between the protrusion and the implant surface, into which cell material can grow and thus provide additional compression by densifying the bone tissue in this area Ensuring fixation of the implant in the bone. By surveys arranged on the implant surface, moreover, the surface which is in contact with the bone tissue is markedly enlarged so that the fixation of the implant in the bone is additionally improved.

In a further particularly advantageous embodiment of the invention, it is further provided that the elevation is oriented such that the surface of the elevation forms an angle of at least approximately 90 ° with the implant surface on the side facing the screwing-in direction. By this measure it is avoided that there are retentions when screwing in the implant or the bone screw, which could make it difficult to insert the implant into the bone. This effect can be exacerbated by the survey on the side facing the screwing rounded and / or convex curved. As a result, there are no corners or edges that could be an obstacle when inserting the implant.

In an advantageous embodiment of the invention it is provided that a plurality of recesses and / or elevations over the circumference of the shaft portion, preferably evenly distributed. The more recesses are provided, the more effective a relaxation of the implant can be prevented, as long as the stability of the implant is not affected thereby. In addition, if a plurality of surveys provided, the surface of the implant, which is in contact with the bone tissue, significantly increased so that the fixation of the implant in the bone is improved overall.

The recess may be, for example, a perforation, a slot, a channel, a trough or the like. The elevation may be, for example, nose-shaped, serrated and / or rib-shaped.

The shank region may be at least partially cylindrical. If the shaft region is additionally or alternatively stepped, this can be more easily introduced into the bone tissue.

In a further advantageous embodiment of the invention it is provided that the threaded portion comprises a self-tapping external thread, so that the implant according to the invention or the bone screw according to the invention can be screwed into the bone in an advantageous manner without previous measures.

In an advantageous embodiment of the invention is further provided that the recess and / or the survey opens into an opening / open. This opening can be connected in a further embodiment with a bore extending within the shaft region. By way of example, this bore can be a continuous channel which connects an inlet opening at the distal end of the implant to an outlet opening arranged at its apical end. The implant according to the invention then allows the targeted application of substances or the introduction of material into the periapical or peri-paraimplantären area after implantation of the implant via the apically arranged outlet opening, for example, a complex external or internal sinus lift by post-implantation possible tissue regeneration control avoid. The implant according to the invention thus makes it possible, for example, to apply various agents, medicaments, cells or substances via the line or the shaft area directly intraoperatively and / or subsequently over a long period of time in one or more further sessions as inductive and / or adjuvant and / or therapeutic Measure. The application of any substances, medicaments and / or cells in the periapical or paraimplantar area is thus made possible, whereby the implant itself persists in its capacity as "carrier or anchor of old standards." That is, a postimplantary delivery treatment of the surrounding tissue It is still possible, especially at the tip of the implant, to administer medicaments, for example antibiotics or growth promoters, making it possible to complicate treatment in the previously inaccessible area even after years of post implantation using the implant according to the invention in that post or peri-implant tissue regeneration is facilitated by application of stem cells of any kind to the periapical area, in that both the recess and the elevation through the opening are connected to the bore of the shaft area The possibility of the application of substances, cells or other material through the distal entrance opening directly into different level areas of the bone bed, ie any bone tissue and, for example, alveolar ridge, sinus, cyst lumen, osteomyelic zone or fracture gap, can occur over the entire or a partial area of the implant or beyond. A particular advantage of the invention in this embodiment is that is prevented by the alignment of the recesses opposite to the screwing and at least approximately parallel to the thread pitch of the threaded portion that pushes when screwing the implant bone material into the recesses and the openings are clogged. By aligning the recesses according to the invention, the openings remain free when screwed into the bone and thus the surrounding tissue accessible, so that a postimplant treatment remains possible.

The shaft region may have at least one fastening element in the bore at the apical end. For example, an access tube, a screw or a plug can be attached to the fastening element. The fastening element may be an internal thread or a part of a plug-in or latching connection. Is an access, for example, a cannula or a Hose, or an access tube attached to the fastener, so the safe and targeted introduction or introduction of substances, cells or other material through the outlet opening in the periapical region is possible in an advantageous manner. By means of an attached in the fastener screw or a corresponding plug, the outlet opening can be closed, and thus between the individual treatments, penetration of foreign bodies or microorganisms are prevented in the periapical operation area.

The shaft region may further comprise at least one fastening means and / or an internal thread at its distal end in the bore. For example, an access tube, a screw or a plug may be attachable to the attachment means. The fastening means may for example be part of a plug-in or latching connection. If an access, which can be a cannula or a hose, for example, or an access tube attached to the attachment means, so the safe and targeted introduction or introduction of substances, cells or other material through the distal input port into the bore is possible in an advantageous manner. By means of an attached in the fastener screw or a corresponding plug, the inlet opening can be closed and thus between the individual treatments, penetration of foreign bodies or microorganisms in the line and possibly. The operation area can be prevented. In a particular embodiment, a dental prosthesis or an adapter for attaching a dental prosthesis can be screwed into the internal thread at the distal end of the lead in the case of a dental implant.

The invention will be explained in more detail below with reference to the figures.

Brief description of the illustrations

It shows Figure 1 is a schematic representation of a longitudinal section through a

Embodiment of the implant according to the invention and

Figure 2 is a schematic representation of a cross section through a further embodiments of the implant according to the invention.

Description of various exemplary embodiments of the invention

FIG. 1 shows, by way of example, a schematic representation of a longitudinal section through an implant 1 according to the invention, which consists essentially of a cylindrical shaft region 2. The shaft region 2 is formed by a hollow, step-shaped cylinder 3, which has a through hole 4 in its interior. The bore 4 extends from an inlet opening 5 at the distal end 6 to an outlet opening 7 at the apical end 8 of the shaft portion 2. The cylinder 3 may be provided on its outer surface completely or partially with an external thread, not shown here for screwing into a bony structure ,

Recesses 9, 19 are distributed over the circumference of the shaft region 2, which contribute inter alia to the anchoring of the implant 1 in the bone tissue, since the tissue can grow into these regions, whereby the connection of the implant 1 to the surrounding bone is intensified. The recesses 9 are channel-shaped and are in each case via an opening 10 with the bore 4 in connection. The channel-shaped recesses 9 are aligned opposite to the screwing in the direction of the distal end 6, ie the recesses 9 are not milled horizontally as usual in the cylinder wall, but obliquely from the distal end 6 in the direction of the apical end 8. The longitudinal axis of the channel-shaped recesses 9 It is arranged approximately parallel to the thread pitch of the external thread, not shown here. The inventive alignment of the channel-shaped recesses 9 ensures that the implant 1 can not loosen in the unlocking, but is additionally fixed, and that the recesses 9 when screwing the implant 1 into the bone no Represent obstacles that could complicate the insertion of the implant 1. In particular, it is avoided in this embodiment that when screwing bone material presses into the channel-shaped recesses 9 and the implant thereby practically fixed. The inventive alignment of the recesses 9 is further ensured that the openings 10 do not clog when screwing the implant 1 and thus can fulfill their purpose as access to the surrounding bone tissue.

The arranged at the apical end 8 recesses 19 are each in the form of a trough, said wells are opposite to the screwing in the direction of the distal end 6 and at least approximately aligned parallel to the thread pitch of the external thread, not shown here. Due to the shallow formation of the trough-like recesses 19 towards the distal end 6, it is avoided that, in this area, when the implant 1 is screwed into the bone tissue, retention occurs which would make insertion of the implant 1 more difficult. In particular, the edge regions on the distal side do not present any sharp transitions which could lead to a "hooking" to the bone, whereas the undercuts at the apical end 8 of the trough-shaped recesses 19 produce sharp edges in the apical edge regions of the recesses 19 , which prevent loosening of the implant 1, wherein an additional fixation of the implant 1 takes place by the ingrowth of bone tissue in the undercuts.

At the apical end 8 of the shaft region 2, which forms the tip of the implant 1, an internal thread 11 is arranged as a fastening element 12 in the bore 4. For example, a conduit, an access tube, a screw, a mandrel and / or a plug may be attached to the fastener 12. In the present embodiment, a screw or a screw mandrel can be screwed into the internal thread 11, so that the apical end 8 can either be closed or provided, for example, with an access line for introducing substances and / or cells into the periapical space. The inner cone of the distal End 6 of the shaft portion 2 is also provided with an internal thread 13 as a fastening means 14, so that the inlet opening 5 can be closed with a screw so that, for example, when healing the implant 1 into the bone tissue no unwanted foreign material or germs can enter the operating area. During healing in the bone, a spacer or healing sleeve may be attached to the fastener 14 to facilitate attachment of a prosthesis after complete healing of the surrounding tissue. If the implant 1 healed in the bone or fused with this, can be screwed into the internal thread 13, for example, a spacer, a prosthesis, a denture or a corresponding adapter. The implant 1 then serves as an anchor for the prosthesis or the dentures in the bone. In this case, the surrounding bone tissue also remains accessible via postimplantation via the entry opening 5 (after removal of the prosthesis, the denture or the adapter), the channel-shaped recesses 9 and, above all, the outlet opening 7 for the application of therapeutic substances. Furthermore, a hose or a cannula or the like can also be connected to the fastening means 14 in order to facilitate the introduction of material into the bore 4.

The bore 4 has in the vicinity of the apical end 8 as an additional fastening element 12, a further internal thread 15 on which also a conduit, an access tube, a screw, a mandrel and / or a plug can be attached. With the aid of the fastening element 12, the shaft region 2 or the bore 4 can be subdivided into different compartments 16, 17, 18. By selectively closing the bore 4 by means of attaching a screw or a plug to one or more fastener (s) 12, the individual compartments 16, 17, 18 are sealed against each other so that a targeted application to different levels of the surrounding tissue on the respective perforations 9 is made possible. If, for example, the compartment 17 is closed by means of a screw screwed into the internal thread 15 and a stylet is screwed into the internal thread 13 with an access line, then therapeutic substances and / or cells can be targeted via the channel-shaped connection. gene recesses 9 of the compartment 18 are introduced into the corresponding level of the surrounding tissue.

Of course, further fastening elements and recesses can also be arranged in the shaft region 2. The implant 1 according to the invention can therefore be used very flexibly due to the variety of design options and can be adapted to different requirements or applications in the (orthodontic) surgical and orthopedic field. Due to the alignment of the recesses 9, 19 according to the invention, the implant 1 is reliably fixed in the bone, so that a relaxation of the implant 1 can be prevented even with immediate loading immediately after insertion. An additional fixation in the bone tissue can also be achieved by a surface structure formed in accordance with the invention. A part or all of the surface of the implant can be provided with elevations or similar structural elements, by which the surface of the implant for improved ingrowth with the bone tissue is significantly increased. Due to the alignment according to the invention of the elevations or similar structural elements opposite to the screwing-in direction and at least approximately parallel to the thread pitch, a loosening of the implant in the unwinding direction can be prevented, so that the implant is fixed very firmly in the bone and can be loaded extremely early. This embodiment and the alignment of the recesses and elevations according to the invention are explained in more detail below with reference to FIG.

FIG. 2 shows, by way of example, a schematic representation of a cross section through the shaft region 21 of a further embodiment of the implant 20 according to the invention, which likewise is shown in this illustration without the external thread provided for screwing into the bone. The shank region 21 is a solid cylinder which has a threaded section, not shown here, in the form of a self-tapping external thread. The threaded portion serves to screw the implant 20 into the bone. The shaft portion 21 further has a plurality of recesses 22, 23, of which two different embodiments are shown here by way of example. All recesses 22, 23 are opposite to the screwing (arrow 24) and aligned parallel or at least approximately parallel to the thread pitch, so that they can not pose any obstacles when screwing the implant 20 into the bone tissue, but the tissue can practically slide past them. The recesses 22, 23 have the shape of an asymmetric depression or trough. Alternatively, the recesses may, for example, have the form of a slot or a groove running along the thread pitch. The inner surfaces of the recesses 22, 23 form on the side facing the screwing, ie the side which lies in the direction of the arrow 24, with the imaginary implant surface in the region of the recesses 22, 23 an angle of at least about 90 °. The angle in this figure is approximately 90 ° for the left-hand recess 22 and more than 90 ° for the right-hand recess. Thus, while the inner surface of the recess 22 is at this point at approximately right angles to the implant surface, the recess 23 due to the larger angle at the appropriate location on an undercut 25, can grow into the cell material. As a result, the hold of the implant 20 in the bone tissue is significantly improved. In addition, by this orientation of the recess 23 opposite to the screwing a sharp edge 26, which represents a clear retention in the direction of rotation (arrow 27), so that a relaxation of the implant 20 is prevented in this direction.

The recesses 22, 23 are further aligned such that the surface of the recesses 22, 23 at the side remote from the screwing, ie the side which lies in the direction of the arrow 27, with the imaginary implant surface at this point an angle smaller than approx 90 °. Further, the surface is rounded in the transition region of the recesses 22, 23 to the implant surface, so that there are no retentions that could hinder screwing the implant into the bone. The implant 20 also has distributed over its circumference arranged elevations 28, which are aligned as the recesses 22, 23 opposite to the screwing (arrow 24) and parallel or at least approximately parallel to the thread pitch. The elevations 28 are serrated in this embodiment, with the tips of the teeth pointing in the direction of rotation (arrow 27). The surfaces of the elevations 28 thus form at the side remote from the screwing with the implant surface an angle smaller than about 90 °, while the surfaces of the elevations 28 at the screwing direction facing side with the implant surface form an angle of more than 90 °. As a result of the alignment of the elevations 28 according to the invention, these form clear retentions in the direction of rotation, so that a loosening of the implant 20 in the bone tissue is prevented. This effect is further enhanced by the fact that cellular material can grow into the spaces between the serrated elevations 28 and the surface of the shaft region 21. In addition, due to the flat or smooth shape of the elevations 28 on the outside thereof, retentions in the screwing direction are avoided, so that the elevations 28 do not represent any obstacles that could make insertion of the implant 20 more difficult.

In particular, from Figure 2 it is clear that by the inventive alignment of the recesses and / or elevations opposite to the screwing and at least approximately parallel to the thread pitch of the threaded portion of the implant improved fixation of the implant in the bone tissue can be achieved without the screwing of the implant is hindered , The implants according to the invention therefore sit very stably in the bone tissue and do not loosen even when the implant is loaded immediately after insertion.

The implants 1, 20 according to FIGS. 1 and 2 may, for example, also be designed or used as bone screws in order to fix medical or therapeutic aids, such as metal plates or pins, in or on a bone.

Claims

claims

1. implant and / or bone screw having at least one shaft portion and at least one threaded portion for screwing into a bony structure, wherein the shaft portion and / or the threaded portion has at least one recess and / or at least one elevation /, characterized in that the recess and / or the survey opposite to the screwing and at least approximately aligned parallel to the thread pitch of the threaded portion is / are.

2. implant and / or bone screw according to claim 1, characterized in that the recess is oriented such that the surface of the recess at the screwing direction facing side forms with the implant surface an angle of at least about 90 °.

3. implant and / or bone screw according to claim 1 or 2, characterized in that the recess is oriented such that the surface of the recess at the side facing away from the screwing with the implant surface forms an angle smaller than about 90 °.

4. implant and / or bone screw according to claim 1, 2 or 3, characterized in that the surface of the recess is flattened on the side facing away from the screwing, convex and / or rounded at the transition to the implant surface.

5. implant and / or bone screw according to one of claims 1 to 4, characterized in that the elevation is oriented such that the surface of the elevation at the side remote from the screwing-in direction with the implant surface forms an angle smaller than approximately 90 °.

6. implant and / or bone screw according to one of claims 1 to 5, characterized in that the elevation is oriented such that the surface of the survey on the screwing direction facing side forms an angle of at least about 90 ° with the implant surface.

7. implant and / or bone screw according to one of claims 1 to 6, characterized in that the survey is rounded at the screwing direction facing side and / or convex curved.

8. implant and / or bone screw according to one of claims 1 to 7, characterized in that a plurality of recesses and / or elevations over the circumference of the shaft portion, preferably evenly distributed.

9. implant and / or bone screw according to one of claims 1 to 8, characterized in that the recess is a perforation, a slot, a channel or a trough.

10. implant and / or bone screw according to one of claims 1 to 9, characterized in that the elevation is nose-shaped, serrated and / or rib-shaped.

11. implant and / or bone screw according to one of claims 1 to 10, characterized in that the shaft region is at least partially formed cylindrically and / or step-shaped.

12. implant and / or bone screw according to one of claims 1 to 11, characterized in that the threaded portion comprises a self-tapping external thread.

13. implant and / or bone screw according to one of claims 1 to 12, characterized in that the recess and / or elevation opens into an opening / open.

14. implant and / or bone screw according to claim 13, characterized in that the opening is connected to a bore extending within the shaft portion.