MODULAR IMPLANT FOR DENTAL PROSTHESES

Abstract: Modular implant for dental prostheses comprising a base (11) provided with means (11a) for stable, but reversible, engagement with a corresponding element (13) for closing the base.

Description: Modular implant for dental prostheses The present invention relates to a modular implant for dental prostheses comprising a base provided with means for stable, but reversible, engagement with a corresponding element for closing the base. It is known in the art relating to the implantation of dental prostheses that there is the need to replace the cavities resulting from the loss of teeth with prostheses made of synthetic material of various types. It is also known that, in order to be able to install in a stable manner said prostheses in the associated seat, it is necessary to provide a fixed pin onto which the tooth itself is cemented. The arrangement of said pins is basically performed in two ways: direct screwing of the pin onto the jaw bone (endosseous implant) or, in the case where the bone has deteriorated and does not allow direct screwing of the pin, the positioning, on the bone, of bases made of biocompatible alloys carrying the pin (juxtaosseous implant) . In both cases, after the gum has been closed again over the bone and over the base, the pin remains projecting from the gum so as to allow cementing of the tooth arid this represents a serious drawback of both techniques in that the pin which projects from the gum, from an early stage, does not have time to form a strong bond and, being subject to axial loads caused by chewing, quickly comes loose, resulting in numerous drawbacks such as pain, difficulty in chewing, and defective contact between bottom and upper teeth. The technical problem which is posed, therefore, is that of providing a dental bone implant which solves the abovementioned problems. These technical problems are solved according to the present invention by a modular implant for dental prostheses comprising a base provided with means for stable, but reversible, engagement with a corresponding element closing the base in the area underneath the gum and with means for supporting the false teeth. Further details may be obtained from the following description of a non-limiting example of embodiment of the invention provided with reference to the accompanying drawings, in which: - Figure 1 shows a front view of an implant according to the invention; Figure 2 shows a cross-section along the plane indicated by II-II in Fig. 1; - Figure 3 shows a front view of a multiple implant according to the invention; - Figures 4 shows a partially sectioned front view of the multiple implant arranged in position; Figure 5 shows a cross-section along the plane indicated by V-V in Fig. 4; - Figure 6 shows a cross-section, similar to that of Fig. 5, of the implant after mounting of the pin in place of the cap; and Figure 7 shows a variation of an example of embodiment of the means for supporting the teeth in the case of a full prosthesis. As shown in Fig. 1, the implant 10 according to the invention is composed of a substantially cylindrical or frustoconical base 11, the bottom part of which is formed in the manner of a fork (Fig. 2), the opposite arms lib of which are integral with a strip 12 of suitable material extending in a substantially transverse direction with respect to the longitudinal axis X-X of the base 11. Said transverse strip 12 is made from material of limited thickness and provided with holes 12a and, during casting, performed on the basis of the imprint of the bone 20 taken beforehand, assumes the shape corresponding to that of the bone 20 itself so as to allow perfect adaptation to the surface of the latter on which it is placed (Fig. 4) . The base 11 has, formed inside it, a female thread 11a designed to engage with the threading 13a of the shank 13b of a cap 13, the top end 13c of which is provided with a hexagonal operating seat 13d. As shown in Fig. 3, the modular implant 10 according to the invention may be constructed in multiple form in all those cases where it is required to replace a plurality of teeth with a corresponding number of prostheses . Practical experience has shown that the implant may advantageously be applied in the form of either a single module or multiple module consisting of up to eight elements distributed along the dental arch and joined together by transverse strips 12 which extend along the jaw bone 20. Figs. 4 and 5 show how the implant 10 is arranged in position: -) after providing suitable seats 21 in the jaw bone 20, taking corresponding imprints and forming the associated implant, -) the gum 30 is opened and the implant 10 (which in the Figures is of the multiple type) is placed on the bone 20 so that the bases 11 are arranged inside the said seats 21 and the inside bottom part of the fork rests axially on the bone 20 on which the strip 12 integral with the opposite arms lib of the fork(s) is also rested (in the transverse direction with respect to the axial direction of the base) . In this way perfect engagement between the bone 20 and the implant 10 is obtained so that the latter is already stable, although still free. Once said engagement has been performed, the threaded holes 11a are closed with the caps 13 and the implant is covered with a granular synthetic material 40 which, over a certain period of time (50-60 days) , becomes hard bone, mixing with the haematic fibrin and securely fixing the implant also owing to the presence of the holes 12a on the transverse strip 12. Once the said material 40 has been applied, the gum 30 is closed over the base 11 and the cap 13, so as to allow the synthetic material 40 time to harden. Once the necessary time has lapsed, the gum 30 is opened again in the region of each base 11, the cap 13 is unscrewed and a corresponding pin 50 (Fig. 6) , onto which the false tooth will be cemented, is screwed in. For the above description two main advantages of the implant according to the invention are obvious: - the base may be applied in a combined endosseous and/or juxtaosseous manner, solving the problems associated with those cases where the bone is particularly fragile and unable to support a screw screwed directly inside it; - the fact of being able to close the gum above the cap 13 for the time needed for the granular material 40 to solidify, forming a single body with the bone 20, and the fact of being able to position the pin 50 easily in the seat subsequently, avoids those forces on the projecting pin which, in the known art, are the main reason for the lack of stability of the implant. Finally, Fig. 7 shows a variation of an example of embodiment of the implant according to the invention, suitable for application to an entire dental arch: in this case the bottom part remains unchanged, but an arch 150 is mounted on the bases and fixed in position by means of stud bolts 151 inserted into corresponding through-seats 152a of columns 152 integral with the said arch 150 and provided at predefined intervals along the length of the arch 150 corresponding to the position of the bases 11 onto the female threads 11a of which the said stud bolts 11a are screwed. Basically the arch 150 replaces the individual pins 50 in those cases where it is required that the whole dental arch should be extractable.

Claims: CLAIMS 1. Modular implant for dental prostheses, characterized in that it comprises a base (11) provided with means (11a) for stable, but reversible, engagement with a corresponding element (13) for closing the base. 2. Implant according to Claim 1, characterized in that the said means for engaging the base (11) consist of a female thread (11a) . 3. Implant according to Claim 2, characterized in that said elements for closing the base consist of a cap (13) with a shank (13b) provided with a threading (13a) designed to engage with the corresponding female thread (11a) of the base (11) . 4. Implant according to Claim 1, characterized in that said base (11) has a bottom part formed in the manner of a fork. 5. Implant according to Claim 4, characterized in that the opposite arms (lib) of said fork are integral with a strip of material (12) extending in a direction which is substantially transverse to the longitudinal axis (X-X) of the base (11) . 6. Implant according to Claim 5, characterized in that said transverse strip (12) of material has holes (12a) . 7. Implant according to Claim 1, characterized in that means (50; 150) for supporting the false tooth may be engaged in said means (11a) for engaging the base (11) • 8. Implant according to Claim 1, characterized in that said support means consist of a pin (50) fastened to the said base engaging means. 9. Implant according to Claims 2 and 8, characterized in that said pin has a shank with a threading designed to engage with the female thread (11a) of the base (11) . 10. Implant according to Claim 7, characterized in that said support means consist of an arch-piece which is fastened to the base by means of said engaging means. 11. Implant according to Claims 2 and 10, characterized in that said arch-piece is fastened to the female thread (11a) of the base (11) by means of the corresponding threading of stud bolts (151) housed in respective seats (151a) formed along the arch-piece itself. 12. Implant according to Claim 1, characterized in that it is endosseous and juxtaosseous . 13. Implant according to Claim 1, characterized in that it is of the multiple type.

Inventors: DI GIULIO ANTONIO TEODOSIO, DI GIULIO GIANCARLO, DI GIULIO, ANTONIO, TEODOSIO, DI GIULIO, GIANCARLO
Applicants: GIULIO ANTONIO TEODOSIO DI, GIULIO GIANCARLO DI, NOMET MANAGEMENT SERV BV, DI GIULIO, ANTONIO, TEODOSIO, DI GIULIO, GIANCARLO, NOMET MANAGEMENT SERVICES B.V.
Application year: 1999
Main classification: A61C8
IPC codes: A61C8