IMPLANT

Abstract: Implant (1) comprising an anchoring part having one or more fixing means (2) as well as a prothesis part adapted to fix a dental prothesis, which implant is provided with a cavity (4) extending form the prothesis part into the anchoring part, the wall of the anchoring part is perforated at one or more spots (5) and the prothesis part is provided with a removable closing means (3) for the cavity; when the implant is implanted the cavity of the implant may contain a medicine for protecting the implant against pathogenic bacteria etc.

Description: Implant Implant as well as a dental prothesis attached to one or more of such implants. The invention relates to an implant comprising on the one hand an anchoring part having one or more fixing means for anchoring the implant to the bone and on the other hand a prothesis part adapted to fix a dental prothesis to the implant. The known and nowadays most applied implants have a metal anchoring part and the form of a plate, needle or screw. With these implants the anchoring is based on the mechanical engagement of the implanted body and the bone by forming of a tissue covering at the interface of the bone and the implanted body. Further, from Dutch patent application 66,03182 implants of ceramic material like metal oxides especially aluminum oxide, -silicates, -carbides, -borides, -nitrides, -suicides or glass are known. These implants having e.g. the shape of pens are placed in hollow roots. However, after the implantation of the known implants whereby the implant is partly in the body ("milieu interieur") and partly outside the body ("milieu exterieur"), as a rule infections appear because the transition region of "milieu interieur" to "milieu exterieur" is a "porte d'entree" for pathogenic bacteria and other pathogenic germs. At this "porte d'entrδe" the bacteria etc. coming out of the oral cavity which in view of the temperature and humidity present therein is an ideal breeding place for a.o. bacteria, penetrate into the body against the plasma stream. The body reacts thereon by starting a defensive reaction inducing the forming of pus. Because of these defensive reactions and the complications belonging thereto normally the placed implant gets lost or should even be removed for stopping a steady expanding infection. The invention is aimed at the removal of the abovementioned objection so that the chances of survival of an implanted implant can be improved substantially. It was found that the above described disadvantage of the known implants can be removed by providing the implant of a hollow cavity which extends from the prothesis part into the anchoring part, the wall of the anchoring part is perforated at one or more spots and the prothesis part is provided with a removable closing OMF means for the cavity. More in particular, in this cavity a medicine like an antibiotic can be placed which by diffusion/osmosis via the perforations present in the wall of the anchoring part will leave the cavity of the implant and will be carried away with the plasma stream in the direction of the "milieu interieur/milieu exterieur". Therefore a considerable concentration of antibiotic is present at the transition region of "milieu interieur/milieu exterieur" so that this "porte d 1 entree" for bacteria etc. is closed. Normally an antibiotic having a broad spectrum like gentamycin is used. Apart from the abovementioned advantage the implants according to the invention have the possibility to make instantaneous views of the condition of the implanted implant at any time. By removing the removable closing means one may carry out a puncture in the implant after which by means of a laboratory test it can be determined which bacteria/cells are present in the implant. In case of the presence of undesired bacteria/cells in the implant it is possible to combat these undesired bacteria/cells by means of a specific medicine. Therefore with the implants according to the invention it is possible to check constantly the condition of the implant and if desired to influence it. Further, it is possible to replenish or to replace the antibiotic present in the implant after some time e.g. at the half yearly check so that an optimum protection of the implant is guaranteed. The implant according to the invention is preferably made of metal, e.g. dental gold having the composition of 65-85 Z gold, 1-4 Z palladium, 1-10 Z platinum, 10-15 Z silver, 0-10 Z copper and 0-1 % zinc. As marketed dental gold metals are mentioned: "Degudent-G" (98 Z noble metal alloy) and "Permador". Next to the above alloys also noble metal alloys are qualified. Except noble metal alloys also other inert alloys having a good resistance against corrosion as well as against strong mechanical loads can be used e.g. alloys on the basis of cobalt, chromium, titanium and molybdenum respectively on the basis of chromium, cobalt and nickel. The fixing means of the anchoring part of the implant is preferably a screw thread of the retinating type having a great speed which speed resembles the one of a marrow screw. The removable closing means for the cavity of the implant is preferably a screw cap which can be screwed on the free end of the prothesis part of the implant. However, also other closing means can be used which depend on the prothesis later to be used on behalf of the rehabilitation of the set of teeth which are under treatment. The diameter of the perforations in the wall of the anchoring part of the implant according to the invention should have such a size that a sufficient passage of body fluids may take place. However, the diameter respectively the number of perforations are limited by the fact that the structural strength of the implant should be considerable in view of the forces which can be expected during the implantation of the implant in the bone. So an uni ocal indication of the diameter respectively number of perforations cannot be given and is also dependent on the material of the implant in question. An embodiment of the implant according to the invention is illustrated in longitudinal section in the enclosed figure 1 in which the implant of the screw pin type (1) made of dental gold comprises a cavity (4) which extends from the prothesis part into the anchoring part. The anchoring part has been provided with a screw thread (2) of the retinating type having a great speed which resembles the one of a marrow screw. The wall of the hollow implant has a thickness of at least 0.4 mm. Further the wall of the anchoring part is provided with one or more perforations (5) having a diameter of 0.5-1 mm. The free end of the prothesis part of the implant is supplied with a screw thread for closing the cavity by means of a screw cap (3). Further the invention relates to a dental prothesis like an artificial tooth, bridge or a complete upper respectively lower set of artificial teeth which is attached to one or more of the implants according to the invention and the cavity of the concerning implant respectively implants mounted in the bone is supplied with an antibiotic. From the experiences gained up to now It has appeared that such dental protheses on the basis of the implants according to the invention do have an optimum lifetime. OMPI When in the post implant period it is definitely evident the implant is settled and there is no more need for a local antibiotic, the cavity inside the implant may be occluded by an obturator (inclusive the perforations) which is screwed in (clockwise) (vide figure 2 illustrating among others an embodiment of the obturator having number (6), whereas the numbers (1), (2), (4) and (5) have the meanings mentioned above). Once the need arises to utilise a local antibiotic again, the obturator may easily be extracted from the cavity by screwing the obturator out (counter clockwise). The cavity is again ready to receive an antibiotic filling and is for instance closed by screwing a screw cap on the top of the implant. C PI

Claims: C L A I M S 1. Implant comprising on the one hand an anchoring part having one or more fixing means for anchoring the implant to the bone and on the other hand a prothesis part, adapted to fix a dental prothesis to the implant, characterized in that the implant is provided with a cavity which extends from the prothesis part into the anchoring part, the wall of the anchoring part is perforated at one or more spots and the prothesis part is provided with a removable closing means for the cavity. 2. Implant according to claim 1 characterized in that the implant is made of metal or metal alloy. 3. Implant according to claim 1 or 2 characterized in that the implant is made of dental gold or another noble metal alloy. 4. Implant according to any one of the claims 1-3 characterized in that the fixing means of the anchoring part is a retinating screw thread. 5. Implant according to any one of the claims 1-4 characterized in that the removable closing means is a screw cap which can be screwed on the free end of the prothesis part. 6. Implant according to any one of the claims 1-5 characterized in that the implant is made of dental gold, the cavity in the implant has a diameter of 2-2.5 mm, the wall of the hollow implant has a thickness of at least 0.4 mm and the perforation openings in the wall of the anchoring part have a diameter of 0.5-1 mm. 7. Dental prothesis attached to one or more implants according to any one of the claims 1-6 characterized in that the cavity of the implant respectively implants contains a medicine. ****** OKPI

Inventors: TON MICHAEL ANDREAS, TON, MICHAEL, ANDREAS
Applicants: TON MICHAEL ANDREAS, TON, MICHAEL, ANDREAS
Application year: 1983
Main classification: A61C8
IPC codes: A61C8