WO2012007696A1

WO2012007696A1 - Implant device and delivery tool

Info

Publication number: WO2012007696A1
Application number: PCT/FR2011/051686
Authority: WO
Inventors: Jean Emmanuel Soffer; Fani Anagnostou
Original assignee: Universite Paris Diderot - Paris 7
Priority date: 2010-07-13
Filing date: 2011-07-13
Publication date: 2012-01-19
Also published as: FR2962641A1; FR2962641B1; EP2593034A1

Abstract

The invention relates to an implant device and a delivery tool. The invention includes an implantable part (10) comprising an attachment portion (14), and a confinement element (44) having an attachment member (52) to engage in said attachment portion (14) of said implantable part in order to hold said confinement element against the bone tissue (12) by forming a confined space (54) around said implantable part. According to the invention, said confinement element (46) includes a rigid bell part (46) having a bottom (50) and an opening (48) opposite said bottom, said rigid bell part (46) having a circular edge (51) defining said opening, which is to be inserted into a circular groove (42) provided in said bone tissue around said implantable part (10), so as to promote the growth of the bone tissue inside said confined space.

Description

IMPLANT DEVICE AND INSTALLATION TOOL

The present invention relates to an implant device for guiding bone regeneration around a dental implant. It also relates to a tool for fitting the implant device.

After having been installed and consolidated, the dental implants are then equipped with a prosthesis reconstituting the morphology of a tooth.

The implementation of dental implants, is conditioned to the available bone volume edentulous ridges. Indeed, there is a correlation between the preimplantation bone thickness and the durability of maintaining the implant in these bone ridges. In addition, the implementation of an implant can be done easily and safely within a bone mass of a height less than about 8 mm. However, the bone ridges are strongly resorbed after dental extractions and the height of the bone mass decreases accordingly.

Also, it has been imagined to promote the neoformation of bone mass at toothless bone ridges so as to increase the volume of preimplantation bone mass.

Reference can be made to US 5,976,140, which specifically discloses a confinement element intended to promote the formation of a complementary bone mass around a dental implant so as to improve its anchoring within the bone mass.

Thus, the implant is anchored in the bone mass, and it has a hooking part for maintaining a confinement element. The latter comprises a sheet of plastically deformable titanium and a fastening member for maintaining the titanium sheet around the implant and at a distance from the bone wall of the bone mass. In addition, the titanium sheet is folded radially against the bone wall and is maintained by means of suitable nails.

Thus, a confined space is formed vertically above edentulous ridges and around the implant. In addition, hydroxyapatite granules are introduced inside the confined space to promote bone growth. Such a device is relatively complex to implement and requires a great skill of the practitioner. In addition, bone growth is relatively modest.

Also, a problem that arises and that aims to solve the present invention is in particular to provide an implant device that is not only simpler to implement, but also that is more efficient.

In order to solve this problem, and according to a first object, the present invention provides an implant device for guiding bone regeneration. Said implant device comprises, on the one hand, an implantable piece able to be implanted in a bone tissue, said implantable piece comprising a hooking part, and on the other hand a containment element having a hooking member intended to come into contact with the bone. engaging said engaging portion of said implantable patch to maintain said containment member against said bone tissue to form a confined space around said implantable patch and to promote growth of bone tissue within said confined space. According to the invention, said containment element comprises a rigid bell piece, said rigid bell piece having a bottom and an opening opposite said bottom, said rigid bell piece having a circular edge delimiting said opening. And said circular edge of said rigid bell piece is intended to engage in a circular groove made in said bone tissue around said implantable piece when said hooking member is engaged in said hooking part, so as to make said confined space watertight.

Thus, a feature of the invention lies in the implementation of a rigid bell part, made of a biocompatible material, whose circular edge, which is free, is engaged in the circular groove to form a tight connection between said rigid bell piece and the bone wall. In this way, there is formed a tight and non-deformable confined space allowing a much better bone growth around the implantable part without the need for a bone graft or other surgical procedure. Moreover, the implementation of the rigid bell piece is easy since it is sufficient to come to apply against the bone wall while engaging its fastening member in the attachment part of the piece implantable. The circular edge of the rigid bell piece is then held against the bony wall within the circular groove without the need for special complementary fastening elements.

Said rigid bell piece has a solid wall. In this way, the wall of the bell-shaped piece extends both above and around the implantable piece substantially embedded in said bone tissue, forming a completely sealed confined space, with respect to the outside of the bone. bone tissue. Therefore, there is no need to provide a complementary device to seal this confined space. It is also not necessary to fold the alveolar mucosa over the bell-shaped part to provide sealing.

In addition, said rigid bell piece has a circular border along said circular edge, said circular edge being substantially cylindrical. In this way, in addition to the circular edge which is free, the circular edge is also engaged within the circular groove, in all the depth of the groove, which is of cylindrical symmetry. This further increases the tightness of the confined space. Here is meant by substantially cylindrical, a circular border of generally frustoconical shape whose top would be very far from the edge.

Advantageously, said hooking member is integral with said bottom of the rigid bell part, and extends longitudinally through said opening. In this way, it is likely to be adjusted in the implantable part by manipulating the bell part without any other precaution. Preferably, said hooking member is centered with respect to said circular edge. And this feature makes it possible to connect the fastening member to the attachment part of the implantable part by simply driving the bell part in rotation, along an axis defined by said fastening member, the latter then remaining oriented according to a predefined axis.

According to a particularly advantageous embodiment of the invention, said hooking member has a threaded free end intended to be screwed into said hooking portion. Also, the implantable part is threaded axially according to a predefined helix pitch so as to receive the threaded free end of the fastening member. And the rotational drive of the rigid bell part then allows to screw the fastener member through the implantable piece as the circular edge of the bell part engages in the circular groove. The bell piece is finally driven in force rotation when its circular edge bears in the bottom of the circular groove so as to locked in rotation by friction. As a result, the joint between the circular edge of the bell piece and the bone wall is sealed.

According to a particular characteristic of the invention, said rigid bell piece is of conical symmetry of revolution, and said hooking member extends substantially along the axis of symmetry of said rigid bell piece.

Consequently, when the implantable piece and the circular groove are coaxial on the one hand and the fastening member and the circular edge are also coaxial, when the bell part is rotated to secure its fastener member with the attachment part of the implantable part, not only its circular edge coincides with the circular groove but also, it can be driven in rotational movement without obstacle, which facilitates the mounting of the rigid bell part.

Such a form of bell-shaped part obviously includes the cases where the apex of the conical symmetry piece of revolution is infinite and therefore where it is of cylindrical symmetry of revolution.

According to a particularly advantageous embodiment of the invention, said rigid bell piece is made of titanium. This obviously includes titanium alloys as well. This material has the advantage of being inert and therefore biocompatible.

In addition, said rigid bell piece has an inner surface, said inner surface being coated with an osteoconductive adjuvant, for example recombinant human morphogenetic bone proteins. In this way, the bone neoformation appears extremely rapidly after the introduction of the rigid bell piece. It will be observed that the implementation of these proteins inside the rigid bell part is facilitated and potentiated because the confined space is sealed.

According to a second object, the present invention proposes a confinement element for an implant device as described above and comprising a rigid bell piece having a bottom and an opening opposite said bottom, said rigid bell piece having a circular edge defining said opening, while said hook member is integral with said bottom and extends longitudinally through said opening.

In addition, the rigid bell piece has a circular border along the circular edge, said circular edge being substantially cylindrical. In this way, in addition to the circular edge which is free, the circular edge is also engaged within the circular groove, in all its depth, which groove is cylindrical symmetry. This further increases the tightness of the confined space. Here is meant by substantially cylindrical, a circular border of generally frustoconical shape whose top would be very far from the edge.

According to a third object, the present invention proposes a tool for fitting an implant device as described above and comprising, a guide rod adapted to engage in said attachment portion of said implantable part and to extend projecting from said implantable part; a hole saw having a sharp circular edge whose diameter is substantially equal to the diameter of said circular edge of said rigid bell piece, and an axial guide hole centered with respect to said sharp circular edge; and said hole saw is intended to be fitted opposite said implantable part so as to be able to engage said guide rod through said axial guide hole and to apply said sharp circular edge against said bone tissue so as to form a circular groove in the groove. bone tissue around said implantable piece, said circular groove being adapted to receive said circular edge of said rigid bell piece.

It will be observed that the sharp circular edge of the bell saw is located at a distance from its axis of symmetry.

Thus, thanks to the laying tool, the circular groove formed in the bone tissue is located at a distance and around the implantable part, and it is perfectly centered on this implantable piece. In this way, the circular edge of the rigid bell piece whose diameter is substantially equal to that of the sharp circular edge of the hole saw, comes perfectly engage in the circular groove. It is thus conferred sealing to the confined space.

Advantageously, said guide rod has a threaded attachment end intended to be screwed into said hooking portion and an opposite guide end. In this way, the guide rod is on the one hand perfectly integral with the implantable part, and on the other hand axially centered relative to it. In addition, said hole saw preferably has a boss extending around said axial guide orifice, said boss being able to abut against said implantable piece to limit the range of said sharp circular edge. Thus, the depth of the circular groove is precisely predetermined with respect to the implantable piece itself. Also, the dimensions of the rigid bell part are themselves predefined according to the geometry of the implantable part. In this way, the circular edge of the bell engages perfectly, and fit sealingly through the circular groove, when the fastening member is engaged in the attachment part, while the bottom of the rigid bell part bears on the implantable part, as will be explained in the detailed description below.

Other features and advantages of the invention will emerge on reading the following description of a particular embodiment of the invention, given by way of indication but not limitation, with reference to the accompanying drawings in which:

- Figure 1 is a schematic axial sectional view of a first element of an implant device according to the invention, implanted in a bone crest;

- Figure 2 is a schematic axial sectional view of the element shown in Figure 1 and a first laying element;

FIG. 3 is a diagrammatic view in axial section of the first elements illustrated in FIG. 2, together with a second laying element;

- Figure 4 is a schematic perspective view of a second element of the implant device; - Figure 5 is a schematic axial sectional view of the first and second element of the implant device cooperating with each other in the bone crest according to the invention and at a first stage of implementation;

FIG. 6 is a diagrammatic view in axial section of the first and second elements of the implant device, as illustrated in FIG. 5, at a second stage of implementation; and,

FIGS. 7A and 7B are vertical axial histological sections including the first and the second element of the implant device produced six months after its implementation according to the invention.

Figure 1 monster an implantable piece 10 commonly called dental implant, and implanted in bone tissue 12. The latter has an upper bone wall 13. This implantable part 10 is generally cylindrical in shape of revolution. It is made of a metal alloy, for example a titanium alloy, and its length can be between 4 mm and 18 mm, for example between 8 mm and 15 mm. Its diameter may be between 1 mm and 6 mm, for example between 2 mm and 4 mm. The implantable part 10 has a hooking part 14, and it is pierced axially with a blind hole 16 opening axially outwards in the hooking portion 14 and which extends longitudinally over two-thirds of the length of the hook. the implantable part 10. The implantable part 10 has an upper end 17 opposite a lower end 19. In addition, the blind hole 16 is threaded axially and thus has a tapping 18. The implantable part 10 illustrated in Figure 1 presents an emergent portion 20 which protrudes from the upper bone wall 13, and which corresponds substantially to one third of the total length of the implantable part 10. It also has a buried portion 22 and anchored in the bone tissue 12 whose length represents substantially two-thirds of its length. When the implantable piece 10 has for example a length of 9 mm, substantially 3 mm correspond to the emergent portion 20. Preferably, the emergent portion 20 has a length of between 2 mm and 4 mm.

The implantable part 10 is permanently installed in the bone tissue 12. In advance, the bone wall is drilled by means of a drill with a diameter substantially smaller than that of the implantable part 10 which is then added force in the drilling thus achieved. In the case illustrated in Figure 1, the bone volume is insufficient, and in particular vertically, to ensure the holding of the piece in time. And thanks to the implant device according to the invention, the appearance of bone neoformations around the emerging portion 20 of the implantable part 10 will help consolidate its anchorage.

After placement of the implantable part 10, as illustrated in Figure 1, a guide rod 24 is fitted inside the implantable part 10. This guide rod 24 has a threaded end 26 and the opposite a smooth guide end 28. The threaded end 26 of the guide rod 24 is screwed into the blind hole 16 through the tapping 18, as illustrated in FIG. 2.

The smooth guide end 28 then extends axially projecting from the emergent part 20 of the implantable part 10. Thus, the guide rod 24 is held axially fixed in the implantable part 10. The attachment portion 14 of the the implantable part 10 is formed by the upper part of the implantable part comprising both the blind hole 16 and the tapping 18.

Then, a bell saw 30 is provided which is illustrated in Figure 3 opposite the implantable part 10. This bell saw 30, in one piece, has a sharp circular edge 32 of frustoconical symmetry of revolution and in contrast a drive shaft 34 centered with respect to the sharp circular edge 32. The sharp circular edge 32 has a cutting edge 33 equipped with teeth. In addition, the bell saw 30 has a bottom 36 and an axial guide hole 38 formed in the bottom wall in the axis of the drive shaft 34 and centrally also with respect to the sharp circular edge 32. An axial boss 40 is arranged projecting from the bottom 36 in the extension of the axial guide orifice 38. It will be explained below its role in the cooperation mode of the bell saw 30 with the implantable piece 10.

As illustrated in FIG. 3, the bell saw 30 is fitted facing the implantable piece 10, itself implanted in the bone tissue 12, so that the smooth guide end 28 of the guide rod 24 is partially engaged within the axial guide hole 38. From this position, the bell-saw 30 is adapted to be guided axially by the smooth guide end 28 and to be driven in translation towards the implantable part 10 until the axial boss 40 comes into abutment against the upper end 17 of the implantable part 10. During this drive in translation, the hole saw 30 is simultaneously rotated by means of its drive shaft 34. It is then guided in rotation around the guide end 28. the guide rod 24. Thus, the circular cutting edge 32 driven in rotation, will dig a circular groove 42 in the upper bone wall 13. This circular groove 42 has the distinction of being centered on the guide rod 24 but also, centered by relative to the blind hole 16 which extends axially in the implantable part 10.

The bell saw 30 described in FIG. 3 in cooperation with the guide rod 24 forms with it a laying tool for which protection is also sought. With this tool, we can adapt another implant element, and more specifically a containment element 44 that will now be described with reference to Figure 4.

This containment element 44 comprises a rigid bell piece 46, or capsule, which may be made of a metallic material, for example titanium. This rigid bell piece 46 is of conical symmetry of revolution and has an opening 48 opposite a bottom 50 and a frustoconical inner wall 49. The opening 48 is delimited by a circular edge 51. It will be observed that the distance separating the circular edge 51 and the bottom 50 in an axial direction, is equal to the distance that extends, in an axial direction, between the axial boss 40 of the hole saw 30 and the cutting edge 33 of the cutting edge 32. By elsewhere, it has an attachment member 52 which is integral with the bottom 50 and which extends axially substantially perpendicularly to the bottom 50 of the rigid bell piece 46 and through the opening 48 to extend projecting. The attachment member 52 consists of a rod having a threaded free end 54 adapted to be screwed through the tapping 18 of the implantable part 10 as will be explained below. It will be observed on the one hand that the hooking member 52 is centered with respect to the circular edge 51 of the rigid bell piece 46, and on the other hand that the diameter of the circular edge 51 is substantially equal to the diameter of the sharp circular edge 32 of the hole saw 30.

In addition, the attachment member 52 extends in a direction substantially perpendicular to the mean plane defined by the circular edge 51 of the rigid bell piece 46.

Thus, this rigid bell piece 46 can be installed on the implantable piece 10 after the bell saw 30 and the guide rod 24 have respectively been withdrawn and unscrewed, as shown in FIG. 5. Also, the free end threaded 54 of the attachment member 52 is engaged through the blind hole 16 axial, while the rigid bell piece 46 is rotated to screw the threaded free end 54 through the tapping 18. As and as the rotational drive of the rigid bell part 46 is carried out, the latter is simultaneously driven in axial translation towards the implantable part 10 while its circular edge 51 penetrates into the circular groove 42 previously formed. The rigid bell piece 46 is rotated until the bottom 50 bears against the upper end 17 of the implantable part 10, while the circular edge 51 is pressed against the bottom of the groove 42 In this way, and this is a feature of the invention, the circular edge 51 and the upper bone wall 13 are sealingly joined and therefore the rigid bell piece 46 forms a sealed confined space 56 around the implantable part 10. This sealed confined space 56 extends on the one hand circularly between the emergent part 20 of the implantable part 10 and the cylindrical inner wall 49 of the rigid bell part 46, and on the other hand vertically between the bottom 50 and the upper bone wall 13.

As illustrated in FIG. 6, it is precisely in this sealed confined space 56 that the bone neoformation will appear rapidly on the scale of a few weeks to consolidate the implantable part 10. In FIG. two thirds of the sealed confined space 56, free after installation of the rigid bell piece 46, is now filled with bone neoformation. Example

The implementation of the implant device according to the invention is carried out according to the protocol described below for experimental purposes. The device was implanted on the femoral processes of rabbit New Zealand White.

First, a cavity 5 mm deep and 3.5 mm in diameter was bored in the femoral processes in a direction substantially perpendicular to their wall. A Implant Diffusion International dental implant 8 mm in length and 4 mm in diameter, implanted at the edge of the turns, was implanted by screwing. It was then buried in bone tissue for a length of 5 mm and emerged 3 mm from the bone wall.

As indicated above with respect to FIG. 3 and after the guide rod 24 has been screwed inside the implant, a bell saw has been fitted whose cutting edge has a thickness of 0.5 mm with an outer diameter of 8 mm and an internal diameter of 7 mm. A circular trench or circular groove was thus produced around the implant with an external diameter of 8 mm and an internal diameter of 7 mm and a depth of 2 mm.

Then, a rigid bell piece whose outer diameter was also close to 8 mm and the internal diameter of 7 mm, was adjusted on the implant, the threaded free end of the fastener having been screwed to through the tapping of the implant until the bottom of the rigid bell piece comes into abutment against the upper end of the implant, while the circular edge was sealingly abutted in the bottom of the circular groove. The circular edge is thus embedded in the circular groove.

Every week, three-dimensional radiological examinations were performed using a Beam cone scanner to monitor the growth of bone tissue.

After 6 weeks of healing, the rabbits were sacrificed. Histological and histomorphometric analyzes were performed at implant level sections as shown in Figures 6A and 6B. Histomorphometric analysis

As a result of placing the rigid bell piece around the implant on the femoral processes of the rabbits, the "en bloc" bone samples were therefore taken after a healing period of 6 weeks.

At this stage, the samples were taken and prepared for a non-decalcified histology study. Sections of 50 microns were made and stained according to the usual bone histology protocol of B20A. Figures 6A and 6B illustrate two of them. We find in these Figures elements identical to those of the schematic representations described above, so we will affect them with the same reference with a sign "'". Thus, FIG. 6A shows the bone wall 13 ', and the bone tissue 12' in which the implantable piece 10 'is anchored, as well as the rigid bell piece 46'. On the other hand, the attachment member which connects the rigid bell 46 'and the implantable part 10' does not appear here because it has been unstructured during the preparation of the cut.

Inside the sealed confined space 56 ', vertical neoformations 60' of the bone tissue are observed and whose apex 62 'extends to the top of the attachment portion 14' of the implantable part 10 ' . The same phenomenon is observed on the section shown in FIG. 6B, where the identical elements have the same references assigned a "" sign.

A significant number of sections also show a vertical bone neoformation inside the rigid bell room and the dome of this bone neoformation extends to the implant neck.

Thus, the implant device according to the invention has the advantage of allowing the implantation of the implant and the increase of the level of bone tissue in the same operating time. In addition, the implant device according to the present invention, thanks to its capsule in particular, allows to increase quantitatively, vertically and horizontally, the volume of bone tissue around a dental implant during the healing phase of the bone tissue.

Also, according to the invention, and more generally, the mode of implementation intended to promote the growth of bone tissue comprises the following steps: a) implanting an implantable piece, for example a dental implant, of length and diameter appropriate to the clinical case, so as to obtain a primary stability of the implant;

b) the guide rod previously described in the implant is screwed. This guide rod emerges from the implant several millimeters and its emerging end is foam;

c) the previously described hole saw is presented on the guide rod; d) making a circular trench, or circular groove, of diameter and depth as described above, around said implantable part;

e) a confined space is created in the vicinity of said implantable part by putting in place a capsule, a rigid bell piece, provided with an attachment member adapted to cooperate with the attachment part of the implantable piece, said capsule can be embedded in the circular trench made in step d);

f) said capsule is held in place for the time necessary to have bone growth over a thickness of between 1 and 7 mm, for example over a thickness of between 2 and 5 mm; and,

g) the capsule is removed and the dental implant is equipped with a dental prosthesis.

Claims

Implant device for guiding bone regeneration, said implant device comprising, on the one hand, an implantable piece (10) adapted to be implanted in a bone tissue (12), said implantable piece comprising a hooking part (14). and on the other hand a containment member (44) having a hooking member (52) for engaging said hooking portion (14) of said implantable piece (10) to hold said containment member ( 44) against said bone tissue (12) forming a confined space (56) around said implantable patch and to promote growth of bone tissue within said confined space; characterized in that said containment member (44) comprises a rigid bell piece (46), said rigid bell piece having a bottom (50) and an opening (48) opposite said bottom, said rigid bell piece having an edge circular (51) defining said opening;

and in that said circular edge (51) of said rigid bell piece (46) is intended to engage in a circular groove (42) formed in said bone tissue (12) around said implantable piece (10) when said hooking member (52) is engaged in said hooking portion (14), so as to render said confined space (56) watertight.

2. Implant device according to claim 1, characterized in that said rigid bell piece has a solid wall.

3. Implant device according to claim 1 or 2, characterized in that said rigid bell piece has a circular border along said circular edge (51), and in that said circular edge is substantially cylindrical.

4. Implant device according to any one of claims 1 to

3, characterized in that said hooking member (52) is integral with said bottom (50), and in that it extends longitudinally through said opening (48).

Implant device according to any one of claims 1 to

4, characterized in that said hooking member (52) is centered with respect to said circular edge (51).

6. Implant device according to any one of claims 1 to 5, characterized in that said hooking member (52) has a threaded free end (54) intended to be screwed into said hooking portion (14).

7. Implant device according to any one of claims 1 to 6, characterized in that said rigid bell piece (46) is of conical symmetry of revolution, and in that said fastening member (52) extends substantially along the axis of symmetry of said rigid bell piece (46).

Implant device according to one of claims 1 to

7, characterized in that said rigid bell piece (46) is made of titanium,

9. Implant device according to any one of claims 1 to

8, characterized in that said rigid bell piece (46) has an inner surface (49), said inner surface being coated with an osteoconductive adjuvant.

10. Confinement element for an implant device according to any one of claims 1 to 9, characterized in that it comprises a rigid bell piece (46) having a bottom (50) and an opening (48) opposite said bottom said rigid bell piece (46) having a circular edge (51) defining said opening (48), while said hooking member (52) is integral with said bottom (50) and extends longitudinally through said opening.

11. Implant device according to claim 10, characterized in that said rigid bell piece has a circular border along said circular edge (51), and in that said circular edge is substantially cylindrical.

Implant device placement tool according to any one of claims 1 to 9, characterized in that it comprises:

- a guide rod (24) adapted to engage in said latching portion (14) of said implantable part (10) and to extend projecting from said implantable part (10);

- a hole saw (30) having a sharp circular edge (32) whose diameter is substantially equal to the diameter of said circular edge (51) of said rigid bell piece (46), and an axial guide orifice (38) centered with respect to said sharp circular edge (32); and in that said hole saw (30) is intended to be adjusted facing said implantable part (10) so as to be able to engage said guide rod (24) through said axial guide hole (38) and to apply said a sharp circular border (32) against said bone tissue (12) to form a circular groove (42) in the bone tissue around said implantable piece (10), said circular groove being adapted to receive said circular edge (51) of said rigid bell piece (46).

Laying tool according to claim 12, characterized in that said guide rod (24) has a threaded attachment end (26) intended to be screwed into said hooking portion (14) and a guide end (28). ) opposite.

14. Installation tool according to claim 2 or 3, characterized in that said hole saw (30) has a boss (40) extending around said axial guide orifice (38), said boss being able to bear against said implantable piece (10) to limit the range of said sharp circular edge (32).