WO2002062256A1

WO2002062256A1 - Three-dimensional dental implant with artificial root

Info

Publication number: WO2002062256A1
Application number: PCT/HU2002/000007
Authority: WO
Inventors: Géza FRIEDREICH
Original assignee: Friedreich Geza
Priority date: 2001-02-07
Filing date: 2002-02-01
Publication date: 2002-08-15
Also published as: HUP0100591A2; HU0100591D0

Abstract

The present invention relates to a three-dimensional dental implant with artificial root, comprising a hollow base body inserted into the upper or lower jawbone and at least one fastening element protruding from the base body. The fastening element (6) has at least two arched legs (7), with said arched legs (7) reaching through holes (3) in the bottom part of the wall of the base body (1), and the upper part of said base body (1) comprises an internally threaded guiding section with a straining and locking element (13) screwed therein, where said straining and locking element (13) puts the fastening element (6, 9) into operating position and closes the internal cavity of the base body (1).

Description

Three-dimensional dental implant with artificial root

The present invention relates generally to dental implantology, and more particularly to an endosseous three-dimensional dental implant with artificial root that can be inserted into a receptor site formed in the upper or lower jawbone, then joined firmly to the bone and thereby made capable of supporting a tooth abutment and a replacement tooth.

Dental prostheses have long been used for aesthetic and medical purposes. Previously, replacement teeth were usually attached to existing, at least partially healthy teeth or roots by means of a so-called crown or bridgework, Though their application is relatively simple, these kinds of prostheses have a common drawback, namely that healthy teeth have to be ground off or in other ways prepared for supporting the prosthesis. Another drawback is that these prostheses cannot be used in the absence of teeth or roots in the proximity of the tooth to be substituted that could serve as a support for the crown or bridgework. Recent improvements in surgical techniques, as well as progress in the field of biocompatible materials, have paved the way for the more and more widespread use of dental implants that are fixed into the jawbone. These implants can be divided into two groups; axially symmetrical and three-dimensional implants. Axially symmetrical implants are joined to the bone by means of threads and/or grooves or recesses in their external surfaces.

German patent DE 4,115,959 discloses a axially symmetrical implant with a cylindrical body comprising a support surface and a threaded end portion, by means of which it can be screwed into and thereby joined to the bone. The base body of the implant has a central cavity that is internally threaded for engaging the threads of an implant extender or connecting branch that is screwed into it. As a disadvantage of this implant it should be mentioned that it can be subjected to load only after a prolonged period of 3-4 months after surgery, and that retention in the bone may be imperfect. A three-dimensional implant of the "disc" type is presented by Tamas Divinyi (Fogέszati implantolόgia [Dental Implantology], Budapest: Springer Verlag, 1994, pp 47-48.) The implant comprises one or two horizontal discs and a vertical shank in the middle. The receptor site of the implant is prepared by cutting into the jawbone from a lateral direction and removing the required amount of bone so that the shank supporting the replacement tooth can get into the desired position. An obvious drawback of this solution is the need for heavy surgery and significant bone loss.

US patent 5,219,287 discloses a three-dimensional implant. The body of this root- form implant is made of an alloy that displays a thermal shape memory effect, and has a capability of contracting before insertion due to temperature change, then regaining its original extended shape after operation, with the protruding legs of the implant engaging into the bone and thereby securing the body of the implant to the bone. Apart from being relatively expensive, this implant requires cumbersome pre- surgery preparation, and also, its retention is less than perfect. The object of the present invention is to eliminate drawbacks mentioned above and provide an implant that can be inserted with a simple surgical operation and without significant bone loss, and at the same time it is safely joined to the bone, thereby increasing the proportion of successful implantations.

Our invention is based on the idea that if the base body and the fastening elements of the implant are realised as separate parts, and the protruding, edge-terminated legs of the fastening elements are mechanically pressed into the bone, then, after the legs have got "built into" new bone, the resulting artificial root will anchor the implant and the tooth abutment firmly and securely in the bone, preventing its displacement and rotation.

So, the object of the present invention is a three-dimensional dental implant with artificial root, comprising a hollow base body inserted into the upper or lower jawbone and at least one fastening element protruding from the base body. The invention is essentially characterised by that the fastening element comprises at least two arched legs, where said arched legs reach through holes in the bottom part of the wall of the base body, with the upper part of said base body comprising an internally threaded guiding section with a straining and locking element screwed therein, where said straining and locking element puts the fastening element into operating position and closes the internal cavity of the base body.

A preferred embodiment of the present invention can be characterised by that the through holes in the wall of the base body are arranged along a single line.

Another preferred embodiment of the inventive implant is characterised by that the through holes in the wall of the base body are arranged along two lines.

Yet another preferred embodiment of the invention has grooves in the top surface of the base body facilitating the insertion or removal thereof.

According to still another preferred embodiment the number of legs of the fastening element is between 2 and 6, with the number of legs thereof being preferably 2 or

3.

According to another preferred embodiment the fastening element comprises a horizontal seat and a plurality of arched legs attached to the seat, with the legs of the fastening element terminating in edges.

According to yet another preferred embodiment the horizontal seat of the fastening element forms a fan seat.

Still another preferred embodiment of the inventive implant comprises a hexagonal socket in the top surface of the straining and locking element.

Finally, another preferred embodiment of the implant is characterised by that it is made of surface-treated titanium.

Details of the implant according to the present invention are exemplified by the attached drawings, where

Fig.1 shows the longitudinal cross-section of the base body of the implant according to the invention,

Fig. 2 is a sectional view of the base body shown in Fig. 1 taken along plane A-A,

Fig. 3 is a sectional view of the base body shown in Fig. 1 taken along plane B-B,

Fig. 4 is the front view of the fastening element according to the invention,

Fig. 5 is the top view of the fastening element shown in Fig. 4,

Fig. 6 shows another embodiment of the fastening element according to the invention,

Fig 7 shows the implant according to the invention inserted into the jawbone, but before it is joined to the bone, while Fig. 8 shows the implant according to the invention after it has been joined to the jawbone.

Fig. 1 shows the longitudinal cross-section of the base body 1 of the implant according to the present invention, while Figs 2-3 show sectional views of the base body 1 taken along different planes. As it can be seen in the drawings, the base body 1 is a hollow body comprising a cylindrical portion and a portion forming a truncated cone. The top end of the base body 1 has an opening, while the bottom end is closed. For easier bone ingrowth, the base body 1 may be formed in such a way that the bottom end thereof has an opening or bore. Also in order to facilitate ingrowth, the outer surface of the base body 1 can be threaded or grooved. The top surface of the base body has grooves for engaging the claws of a gripping tool during the insertion of the implant into a receptor site formed in the bone, or during the removal of the implant. A threaded guiding section 2 is formed in the upper part of the internal cavity of the base body 1 for receiving and retaining an externally threaded straining and locking element 13. After joining the base body 1 to the bone, the guiding section 2 serves for retaining the tooth abutment. If, for an unforeseeable reason, the implant has to be removed, the guiding section 2 also serves for receiving and retaining the removing tool. Below and above the threaded guiding section 2 the cross-section of the inner surface 5 of the base body 1 is hexagonal. The role of the hexagonal surface is twofold. First, during the insertion of the fastening elements 6 into the bone, the edges 4 of the hexagonal surface orient the legs 7 of the fastening elements 6 and prevent the fastening element 6 from swivelling. Second, the hexagonal inner surface guides the tooth abutment screwed into the implant and prevents the unwanted swivelling thereof. In the bottom half, preferably in the bottom third of the base body 1 , through holes 3 are formed in the wall of the base body 1. Axes of the holes 3 meet the longitudinal axis of the base body at acute angles, and, for safe insertion of the legs 7 of the fastening element 6 into the surrounding cortical bone 14, internal rims of the holes 3 are rounded off. In order to enable the implant to^' receive two fastening elements 6, the embodiment shown in Fig. 1 has holes 3 arranged along two different planes. Axes of the holes 3 meet at 120§, with the two sets of holes 3 arranged in a rotated way with respect to each other. This configuration is especially advantageous for implants used with bigger teeth or with teeth subject to greater masticatory loads. The claim of the invention includes, of course, embodiments with holes arranged along a single plane. The number of holes should be chosen so as to accord with the number of legs of the fastening element. As Figs. 4 and 5 show, the fastening element 6 is shaped to form a stool with flexible, arched legs 7. The fastening element 6 comprises a horizontal seat 8 and outwardly bending arched, tapering legs 7. The legs 7 terminate in edges to facilitate penetration through holes of the base body 1 and into the surrounding cortical bone. The number of legs of the fastening elements can vary between 2 and 6, and it would be inexpedient to raise this number above 6, When, as in the case of replacing a first incisor, there is little space for the insertion of the implant, it is profitable to employ a fastening element 9 having only two legs 10. Here legs 10 are joined by a fan seat 11. The sector-shaped fan seat 11 prevents the fastening element 9 from tipping or turning. Different selections of two- and three-legged stools can be used under varied circumstances to answer a wide range of needs.

Fig. 7 shows the assembled implant before it is joined to the jawbone. The base body 1 of the implant is inserted into the spongy 14 and cortical 15 parts of the bone. When the fastening element 6 is introduced into the internal cavity of the base body 1 , the flexible, arched legs 7 of the fastening element 6 are guided along the edges 4 of the hexagonal inner surface 5 of the base body 1. A tensioning and locking element 13, forming a cylindrical threaded rod, is attached to the fastening element 6. The tensioning and locking element 13 has a rounded-off bottom surface which adjoins to the fastening element 6, while the upper surface of the tensioning and locking element 13 comprises a hexagonal socket 12 for engaging a wrench. The threaded body of the tensioning and locking element 13 can be screwed into the base body 1.

In Fig. 8 the implant according to the present invention can be seen after it has been joined to the bone. Referring to Figs. 7 and 8, the insertion process can be described as follows. First, the base body 1 is inserted into a receptor site formed in the bone. Second, the fastening element 6 is introduced into the internal cavity of the base body 1. As a next step, the tensioning and locking element 13 is employed to push the fastening element 6 further into the internal cavity of the base body 1. Then, by screwing the tensioning and locking element 13 into the base body 1 , the flexible, arched legs 7 of the fastening element 6 are passed along the internal edges of the implant till they reach the holes 3 in the bottom third of the implant. Further screwing the tensioning and locking element 13 results in the legs 7 penetrating through the holes 3 and into the surrounding bone. To eliminate the danger of infection, the tensioning and locking element 13 should be left inside the implant until post-operative healing is complete, or until the implant can be subjected to regular loads. Finally, after the implant is firmly joined to the bone, the tensioning and locking element 13 should be removed and replaced by a tooth abutment.

The implant can be made of biocompatible metal or plastic, preferably of surface- treated titanium or titanium alloy. Also, the base body 1 can be covered with plasma-sprayed coating to which bone tissue adheres particularly well. Surface treatment by hydroxilapatit of the base body 1 can be advantageous as well. Beside safe and firm attachment to the bone that eliminates the possibility of displacement or rotation, advantages of the three-dimensional dental implant with artificial root described in the present invention include minimising the amount of bone lost during implantation, lack of need for major surgery, and a shortened healing period after which the implant can be fully loaded.

List of references

base body internal thread hole edge inner surface fastening element leg seat fastening element leg fan seat socket straining and locking element spongy bone cortical bone groove

Claims

1.Tree-dimensional dental implant with artificial root, comprising a hollow base body inserted into the upper or lower jawbone and at least one fastening element protruding from the base body, characterised by that the fastening element (6, 9) comprises at least two arched legs (7, 10), where said arched legs (7, 10) reach through holes (3) in the bottom part of the wall of the base body (1), with the upper part of said base body (1 ) comprising an internally threaded guiding section with a straining and locking element (13) screwed therein, where said straining and locking element (13) puts the fastening element (6,9) into operating position and closes the internal cavity of the base body (1 ).

2. The implant according to Claim 1 , characterised by that the through holes (3) in the wall of the base body (1 ) are arranged along a single line.

3. The implant according to Claim 1 , characterised by that the through holes (3) in the wall of the base body (1 ) are arranged along two lines.

4. The implant according to any one of Claims 1-3, characterised in that there are grooves in the top surface of the base body (1 ), facilitating the insertion or removal thereof.

5. The implant according to any one of Claims 1-4, characterised by that the number of legs of the fastening element (6, 9) is between 2 and 6, with the number of legs thereof being preferably 2 or 3.

6. The implant according to Claim 5, characterised by that the fastening element (6) comprises a horizontal seat (8) and a plurality of arched legs (7) attached to the seat (8), with the legs (7) of the fastening element (6) having terminal edges.

7. The implant according to Claim 6, characterised by that the horizontal seat of the fastening element (9) forms a fan seat (11).

8. The implant according to any of Claims 1-7, characterised by that there is a hexagonal socket (12) in the top surface of the straining and locking element (13).

9. The implant according to any of Claims 1-8, characterised by that it is made of surface-treated titanium or titanium alloy.