EP0608216A1

EP0608216A1 - Multi-component dental implant

Info

Publication number: EP0608216A1
Application number: EP91918359A
Authority: EP
Inventors: Jean Perisse
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-04-20
Filing date: 1991-10-09
Publication date: 1994-08-03
Also published as: WO1993006787A1; FR2663836A1; FR2663836B1; US5417569A

Abstract

L'invention concerne un implant dentaire multibloc en vue de la mise en place et du maintien d'une prothèse (12) sur un site osseux. Cet implant comprend une suprastructure possédant une queue (5) apte à subir une expansion radiale, grâce à des fentes longitudinales. Une file de billes est disposée dans ladite queue, la dernière bille venant en appui contre une rampe conique de la queue en vue de pouvoir assurer son expansion ou sa libération. La file de billes peut être déplacée en manoeuvrant une vis (10) située au voisinage de l'extrémité libre du faux moignon de la suprastructure. L'implant conforme à l'invention peut être fixé de façon précise dans la racine implantaire (1) et retiré facilement en cas de besoin.The invention relates to a multi-block dental implant for placing and maintaining a prosthesis (12) on a bone site. This implant comprises a superstructure having a tail (5) capable of undergoing radial expansion, thanks to longitudinal slots. A row of balls is arranged in said tail, the last ball bearing against a conical ramp of the tail in order to be able to ensure its expansion or its release. The line of balls can be moved by maneuvering a screw (10) located near the free end of the abutment of the superstructure. The implant according to the invention can be fixed precisely in the implant root (1) and easily removed if necessary.

Description

MULTIBLOCK DENTAL IMPLANT

The invention relates to a multiblock dental implant, intended for placing and maintaining a dental prosthesis on a bone site. It extends to the parts of this implant as well as to the prosthetic assemblies produced from it.

Dental implantology is moving more and more towards multi-block implants which consist of two separate parts, placed successively: on the one hand, an implant root formed by a tubular part which is anchored in the bone site, d 'on the other hand, a suprastructure composed of a tail fixing on the implant root and a false stump supporting the prosthesis. In the so-called straight implants, the abutment and the fixation tail have collinear axes, while in the so-called pre-angled implants, the axes of these elements form an angle of up to 20 °. The implant root is first anchored in the bone site by screwing or any other means (patents DE 1,961,531, EP 0.114.955, US 3-708.883 ...), then the suprastructure is subject to said implant root by means of its fixing tail so that the abutment comes to be in the appropriate position. Currently, this fixation of the tail in the implant root is essentially carried out by two techniques.

Firstly, the tail of the suprastructure being constituted by a smooth rod, this is definitively sealed in the tubular implant root by means of a cement; however, in case of clinical problems, it is no longer possible to remove the suprastructure.

In the other known fixing technique, the tail of the suprastructure is screwed into the implant root by means of a thread and a tapping which are provided on these elements (cf. US Pat. No. 3,589,011). The suprastructure is then removable, but its positioning is imprecise, both in the longitudinal direction (along the axis of the implant) because it is difficult, during screwing, to determining the tightening stop limit, as regards the orientation of said suprastructure around its axis because this orientation conditioned by the end of screwing position is very random; this angular imprecision constitutes a serious defect in the case of pre-angled implants which are very delicate to position appropriately with this type of fixation.

The present invention proposes to provide an improved multiblock implant, free from the above-mentioned defects. It aims to allow precise fixation of the suprastructure on the implant root (deep along the longitudinal axis and angularly around this axis), while preserving the ability to easily remove this suprastructure when necessary.

To this end, the multiblock dental implant targeted by the invention is of the type comprising, on the one hand, a suprastructure provided with a false stump supporting the prosthesis and a tail for fixing it, on the other hand, a tubular implant root adapted to be anchored in the bony site and to receive the tail of the suprastructure; according to the present invention, said implant is characterized in that:

. the suprastructure is provided with a hollow core extending over its entire length, said hollow core opening at the free end of the abutment and being provided with a converging ramp at the free end of the tail,

. the tail of said suprastructure is provided with slots extending over a part of its length from its free end, in order to delimit several sectors capable of undergoing radial expansion,

. several balls are housed in line in contact with each other in the hollow core of the suprastructure, the last ball called expansion ball coming to bear on the converging ramp of the tail so as to be retained by it and at ability to exert spreading pressure on the tail sectors,

. a screw is screwed into a tapped portion of the hollow core near the free end of the false stump, said screw pressing against the first ball in order to allow the row of balls to be moved and blocked. Thus, in the implant of the invention, the tubular implant root which is in itself of known type, is anchored in the bone site in a traditional manner, for example by screwing or by any other known means. The suprastructure is fixed to this implant root by introducing its fixing tail inside it and positioning it appropriately, angularly and along the longitudinal axis. It then suffices to actuate the upper screw to generate the expansion of the tail and its blocking inside the implant root; this maneuver does not modify the axial and angular position of the suprastructure so that it is precisely fixed in the chosen position. To remove the infrastructure, simply activate the screw in the opposite direction: the fixing tail is then radially released and can be extracted.

The implant according to the invention can be of the straight type; the tail and the abutment of the suprastructure then have collinear axes. It can be pre-angled; the axes of the tail and the abutment in this case form a predetermined angle, for example 6 °, 12 ° or 20 °.

The invention extends to a suprastructure of the above-defined type for dental implant, characterized in that it has a hollow fixing tail provided with longitudinal slots in order to delimit several sectors capable of undergoing radial expansion, and in that that said suprastructure is pierced longitudinally with a hollow core provided at the end of the tail with a converging ramp and at the end of the abutment with a tapped portion, a line of balls being inserted in said hollow core between the converging ramp and a screw screwed into the tapped portion.

Other characteristics, objects and advantages of the invention will emerge from the description which follows with reference to the appended drawings, which present, by way of non-limiting examples, two embodiments; on these drawings which form an integral part of this description:

- Figures 1 and 2 are axial sections on an enlarged scale representing a preangulated implant according to the invention, respectively its suprastructure and its implant root;

FIG. 3 is a cross section of the suprastructure by a plane AA,

FIG. 4 is a schematic section showing the implant and its prosthesis in place on the site,

- Figure 5 is a schematic section of another embodiment (straight implant) ready to receive a clipped prosthesis.

The multiblock dental implant shown by way of example in FIGS. 1-4 (scale of the order of 8) is a preangulated implant with an angle equal to 12 °. It is composed of an implant root 1 (FIG. 2), for example made of titanium, which has a tubular shape with a cylindrical hollow core 1a closed by a hemispherical bottom 1b. On its external cylindrical face, this part has a thread 2 for its conventional anchoring in the maxillary site.

The other part of the implant, called the suprastructure 3 (FIG. 1) is also made of titanium and comprises a false stump 4, a tail 5 and a gingival junction 6 between these elements. The longitudinal axis X of the abutment forms an angle of 12 ° with the longitudinal axis Y of the tail. Shoulders such as 6a and 6b limit the gingival junction 6: they are called to correspond respectively with the bone / gum interface and with the external surface of the gum, as illustrated in FIG. 4.

The suprastructure 3 is pierced right through along its longitudinal axes X, Y with a hollow core 7 of circular section. At the free end of the tail 5, this hollow core 7 comprises a frustoconical ramp 8 whose angle at the top is in particular between 45 ° and 75 °, in the example of the order of 60 °. In addition, the hollow core 7 is tapped over a portion of its length 9 at the free end of its false stump.

The tail 5 of the suprastructure has an external diameter slightly less than the bore of the root implant 2 to be able to lodge with gentle friction therein; it is separated over a part of its length into several segments such as 5a by longitudinal slots 13 (in the example four in number) which start from the free end of the tail. Thus, this tail portion can undergo a radial expansion by the play of the elasticity of the segments 5a.

The hollow core 7 of the suprastructure is in the example provided with several balls such as 11a, 11b, arranged in file one in contact with the other between the conical ramp 8 and a screw 10 screwed into the tapped part 9. These balls have a diameter slightly smaller than that of the hollow core 7 in order to be able to move longitudinally therein. The last ball 11a, called the expansion ball, comes into contact with the conical ramp 8, while the other balls such as 11b transmit the longitudinal movement of the screw 10 to it, the first ball of the line being in contact with this screw . The screw 10 has an imprint 10a which allows it to be maneuvered by means of an awl key. Thus, the practitioner can generate a longitudinal displacement of the row of balls, determining an engagement of the expansion ball 11a on the conical ramp 8 and, consequently, a spacing pressure on the segments 5a; it can release these segments by performing the reverse maneuver.

Figure 4 shows the implant installed on site with his prosthesis 12. The practitioner anchors the implant root 1 in the bony site of the maxilla in the traditional way. He then introduces the tail 5 of the suprastructure into the implant root; it positions said tail axially and angularly to give the false stump 4 the ideal position and orientation, then maneuvers the screw 10 in order to arrange the tail 5 in its expanded state and to block it in the implant root. The suprastructure can be removed if necessary by a reverse operation of the screw which releases the tail segments.

The prosthesis 12 is fixed to the abutment 4 by any known means. In the example shown, this prosthesis is ceramic and has an internal yoke metal 12a which is glued to the abutment. Of course, the false stump of the implant according to the invention can be adapted to allow any other type of fixation of the prosthesis, for example fixing by screwing (by means of combined threading and tapping provided on the false stump and the prosthesis, or by clipping as shown in Figure 5).

This FIG. 5 is aimed at the case of a straight implant (common axis Z of the tail and of the abutment), the abutment of which is provided with a clipping head.

It should be noted that the prosthesis put in place can if necessary be provided with a channel of dimensions greater than the imprint 10a of the screw to allow access to it and to maneuver it after putting in place said prosthesis. The prosthesis thus placed is of the fixed type, but can however be easily removed by the practitioner at any time. The access channel to the screw 10 can be blocked by any means which will be extracted by the practitioner at the desired time.

Claims

CLAIMS 1 / - Multiblock dental implant, for the establishment and maintenance of a prosthesis on a bone site, comprising, on the one hand, a suprastructure (3) provided with a false stump (4) support prosthesis and a tail (5) for fixing it, on the other hand, a tubular implant root (1) adapted to be anchored in the bone site and to receive the tail (5) of the suprastructure, said implant being characterized in what:

. the suprastructure (3) is provided with a hollow core (7) extending over its entire length, said hollow core opening at the free end of the abutment (4) and being provided with a converging ramp (8) to the free end of the tail (5),

. the tail (5) of said suprastructure is provided with slots (9) extending over a part of its length from its free end, in order to delimit several sectors (5a) capable of undergoing radial expansion,. several balls are housed in line in contact with each other in the hollow core (7) of the suprastructure, the last ball called the expansion ball coming to bear on the converging ramp (8) of the tail so as to be retained by it and to be able to exert a spacing pressure on the sectors (5a) of the tail,

. a screw (10) is screwed into a tapped portion (9) of the hollow core in the vicinity of the free end of the abutment (4), said screw coming to bear against the first ball (11b) in order to allow move and block the line of marbles.

2 / - dental implant according to claim 1, characterized in that the converging ramp (8) is a frustoconical ramp with an angle at the apex between 45 ° and 75 °.

3 / - dental implant according to one of claims 1 or 2, straight type in which the tail (5) and the abutment (4) of the suprastructure have collinear axes.

4 / - dental implant according to one of claims 1 or 2, of the pre-angled type in which the tail (5) and the abutment (4) of the suprastructure have axes forming between them a predetermined angle.

5 / - Suprastructure for dental implant comprising a false stump (4) prosthesis support and a hollow fixing tail (5), characterized in that the tail (5) is provided with longitudinal slots (9) in order to delimit several sectors (5a) capable of undergoing radial expansion, said suprastructure being pierced longitudinally with a hollow core (7) provided at the end of the tail (5) with a converging ramp (8) and at the end of the false stump (4) of a threaded portion (9), a row of balls (11a, 11b) being inserted in said hollow core between the converging ramp (8) and a screw (10) screwed into the threaded portion. 6 / - Suprastructure according to claim 5, provided with a prosthesis (12) secured to its abutment (4) by gluing, screwing or clipping.