EP1855732A1

EP1855732A1 - Bone implant

Info

Publication number: EP1855732A1
Application number: EP05714379A
Authority: EP
Inventors: Roland Dricot
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-02-24
Filing date: 2005-02-24
Publication date: 2007-11-21
Also published as: WO2006089380A1; US20080020349A1; CA2602419A1

Abstract

The invention concerns an implant comprising a structure (1) provided with an osteogenetic coating (2), said coating comprising calcium sulphate.

Description

Bone implant

The present invention relates to an implant comprising a structure provided with an osteogenic coating.

Document US Pat. No. 5,344,654 discloses an implant provided with a coating based on substantially pure osteogenic protein. This implant is intraosseous because it is intended to extend only into a cavity created in a bone.

This implant introduced into a cavity artificially created in a bone does not include fixing or positioning means, the attachment of the implant being operated by the proliferation and differentiation of cells generating bone tissue. As long as the bone is not formed, the implant is not held properly in place. The implant of this document is unable to form a bone volume out of its cavity and is therefore incapable of reconstructing bone loss in the maxilla, in particular to create bone around the implant placed in the maxillary sinus still existing of a mammal, especially man. The implant according to this document is therefore incapable of forming bone out of the cavity created in the bone.

The reconstruction of maxillary bone loss is a major problem in maxillofacial surgery, particularly in the case of maxillary bone atrophy in edentulous patients who are candidates for dental implants. Classically, to pair a patient with a maxillary cast of an implant-supported prosthesis, it is necessary to go through three distinct stages, which are spread out over time for about a year:

1 °: The establishment of a graft by sinus lift or apposition;

- 2 °: the placement of implants;

- 3 °: The establishment of the implant-supported structure (the dental prosthesis). To remedy this drawback, the applicant proposed in his application WO2004 / 054463 an implant which after attachment to a bone part, allows the formation of bone in a non-bone area, so as to ensure excellent fixation of the bone. implant, the latter can then be used as a basis for an implant-supported structure, such as a dental prosthesis. The implant, according to this application, thus allows its implementation even on bone heights considered insufficient for conventional implants. This implant comprises a structure provided with an osteogenic coating or capable of becoming osteogenic, this coating being in the form of a matrix comprising a solid reinforcement, in particular a reinforcement based on calcium phosphate.

The applicant has now noticed that by using an osteogenic or osteogenic coating comprising pharmaceutical grade calcium sulfate, it was possible to accelerate bone growth, while ensuring a high quality of vascular assistance, and therefore a high degree of bone formation success around the implant, even if the implant or part thereof extends into an air cavity, such as a sinus cavity. The invention thus makes it possible to quickly form a volume of armed bone (due to the presence of the structure bearing the osteogenic coating) in and out of a natural or non-natural bone cavity, for example in a partially bony cavity, in a cavity intraoral, in a transosseous cavity or in a periosteal cavity, for example in a sinus, or in a cavity between two parts of bone, but also in an air cavity, etc. The fact that the structure provided with the osteogenic coating is intended to form a volume of armed bone after the placement of the structure, ensures quickly and reliably excellent attachment between the structure and a large volume of bone. The bone volume formed from the osteogenic lining is advantageously at least equal to 25% of the volume of the structure, advantageously more than 50% of the volume of the structure, preferably greater than the volume of the structure, for example between 1 and 10 times the volume of the structure.

The implant according to the invention comprises a structure provided with an osteogenic or osteogenic coating, said implant advantageously comprising a positioning or fixing means adapted to cooperate with a living bone part or a part able to be transformed into tissue. bone, such as a graft. In particular, the positioning means is adapted to ensure positioning of the implant relative to the living bone portion, said positioning means being adapted to be in contact with at least one zone of a bone portion and adapted to provide a colonizing the osteogenic lining or layer with bone cells from an area of the adjacent bone wall of the area in contact with the positioning means or from substantially only the area of the bone wall in contact with said positioning means. The implant according to the invention since it allows osteogenesis from the vicinity of the positioning or fixing means is an at least partially extra-osseous implant and / or an implant extending at least partially in a bone cavity and or an implant extending at least partially in an air cavity. In addition, the implant according to the invention allows osteo integration when it is placed only in a bone graft or in an osteogenic material graft placed in a sinus or in bone.

Advantageously, the osteogenic or osteogenic coating comprises calcium sulfate in its dihydrate or alpha hemihydrate form, optionally a mixture of these forms.

Preferably, the osteogenic or osteogenic lining comprises calcium sulphate, advantageously in its dihydrate or alpha hemihydrate form, mixed with a binder advantageously bio-absorbable. This binder thus forms a bond between grains or particles of calcium sulphate.

For example, the binder comprises at least one polymeric binder, in particular a biopolymeric binder, for example collagen, hyaluronic acid, thrombin, prothrombin, preferably a cellulose derivative, such as carboxymethyl cellulose.

According to a preferred embodiment, the osteogenic or osteogenic-forming coating comprises from 5 to 95% by weight, advantageously from 10 to 85% by weight, preferably from 25 to 75% by weight of calcium sulphate expressed in the form of anhydrous or CaSO ₄ relative to the dry weight of the coating or the weight of the coating free of free water, for example after a drying step at 100 ^° C.

According to a detail of one embodiment, the osteogenic or osteogenic coating comprises calcium sulfate in the form of particles having a mean particle size by weight of between 1 μm and 1 mm, advantageously between 5 μm and 750 μm, preferably between 10 μm and 250 .mu.m.

According to a feature of one embodiment, the osteogenic coating or capable of becoming osteogenic after removal of the optionally present free water consists essentially of calcium sulfate in its hemihydrate and / or dihydrate form.

According to another detail, the osteogenic or osteogenic coating has a porosity comprising pores with a mean diameter by weight between 10 nm and 1000 μm, advantageously between 1 μm and 800 μm, preferably from 10 μm to 600 μm, in particular 15 μm to 100 μm for micropores and between 100 and 600 μm for macropores. According to a feature of an advantageous form, the coating comprises a non-resorbable or weakly resorbable material, advantageously in an amount of between 0.1 and 25% by weight, preferably 0.5 to 20% by weight, relative to total weight of the coating comprising calcium sulfate in dry form or free of free water. Preferably, the nonabsorbable or weakly absorbable material is a non-osteotransducer or weakly osteotransducer material, in particular hydroxyapatite. The hydroxyapatite is, for example, of natural origin, for example underwater or terrestrial plants, for example corals or coral organisms, or of synthetic origin, such as hydroxyapatite or dicalcium-deficient hydroxyapatites or hydroxyapatites depleted in dicalcium. Other non-osteotransducer materials are amorphous calcium phosphate, for example in the form of a sol-gel (sol-gel transition), crystals of dicalcium phosphate dihydrate, carbon apatite.

According to a preferred form of implant containing hydroxyapatite, the calcium sulphate weight ratio expressed in anhydrous form / hydroxyapatite is between 20: 1 and 1: 20, advantageously between 15: 1 and 1: 2, preferably between 10: 1 and 2: l.

In the case where the implant contains a non-resorbable or weakly resorbable material (for example less than 25% is resorbed in 6 months), the non-resorbable or weakly absorbable material, in particular hydroxyapatite, is in the form of particles having a mean particle size by weight between 1 μm and 1 mm, advantageously between 5 μm and 750 μm, preferably between 10 μm and 250 μm.

In an advantageous form, the coating is substantially free of free water. This coating is for example brought into contact with a liquid medium before being implanted, for example with blood or a medium derived from blood, with a liquid medium containing one or more agents or additives, such as for example one or more antibiotics, growth factors, coagulation factors, etc.

According to one embodiment, the coating comprises from 5 to 200% by weight of free water relative to the weight of the free water-free coating, advantageously from 15 to 100%, preferably from 20 to 75% by weight of free water.

According to details of embodiments, the coating comprises at least one bone growth or bone growth control factor, and / or an antibiotic, and / or calcium phosphate and / or calcium carbonate and / or hydroxyapatite and / or tricalcium phosphate and / or an osteogenic ceramic and / or a material capable of forming an osteogenic ceramic. Tricalcium phosphate when used is preferably the beta form of tricalcium phosphate. The coating may also contain, in addition to calcium sulfate, a mixture, for example a mixture of hydroxyapatite and tricalcium phosphate. The coating may also be in the form of an osteogenic ceramic containing calcium sulfate. The coating may be in the form of a two-layer or multi-layer product, for example with a material located between two layers or sandwiched between two layers. For example, hydroxyapatite can be placed between two layers of calcium sulfate (with or without hydroxyapatite).

The coating advantageously forms a network or "scaffold" or osseointegration structure.

The coating advantageously has a macroporosity of between 100 and 600 microns allowing cell invasion allowing osteoinduction. The positioning means, in particular fixation advantageously has at least one channel or passage or gutter adapted to ensure bone development from the bone part to the structure provided with an osteogenic coating or able to become osteogenic. In particular the channel or passageway is provided with a coating promoting the colonization of cells generating bone or able to generate bone and the transfer of cells to the coating of the structure. For example, the passage or channel is provided with a coating similar to that used for the structure.

Advantageously, the implant comprises at least two separate channels or passages adapted to ensure bone development from the bone part to the structure provided with an osteogenic coating or capable of becoming osteogenic.

Preferably, the channels or passages are placed substantially symmetrically with respect to the fixing means.

According to a particular embodiment, the implant comprises three channels or passages placed symmetrically with respect to the positioning or fixing means. This ensures a substantially homogeneous colonization osteogenic coating or able to become osteogenic.

According to a detail of an embodiment, the fastening means has a substantially cylindrical or substantially frustoconical outer side face provided with a thread adapted to cooperate with a thread of a hole formed in the living bone part. The fixing means is advantageously fixed by screwing into a hole formed in the bone wall, advantageously said hole being threaded. The upper part of the attachment means (part opposite the part of the fastening means adjacent to the structure covered with an osteogenic coating or capable of becoming osteogenic) closes or closes the hole. Advantageously, the channel or passages extend on the lateral outer face along an axis substantially corresponding to a generatrix of the lateral face. According to an advantageous feature, the channel or channels do not extend over the entire length of the side face of the fastening means.

According to an advantageous embodiment, at least one channel or passage has a minimum cross-sectional area of more than 1 mm ² , advantageously more than ² mm ² , for example 3 mm ² , 4 mm ² , 5 mm ² , or more, etc.

According to embodiments, the average total passage section of the channel or channels corresponds to at least 5%, advantageously at least 10%, preferably at least 15% of the average cross section of the substantially cylindrical or frustoconical face at the surface. of which are formed the channel or channels. In particular, the passage section of the channel or channels corresponds to at most 60%, advantageously at most 45%, preferably at most 30% of the average cross section of the substantially cylindrical or frustoconical face on the surface of which are formed the channel or channels.

For example, the implant has a diameter or maximum width of less than 15mm and a total length of less than 30mm.

Advantageously, the structure provided with an osteogenic or osteogenic-capable coating has one or more grooves and / or grooves to promote bone colonization, these grooves advantageously forming an extension of a passage or channel of the fixation means, while that the grooves extend substantially perpendicular to the axis of the implant.

Advantageously, the fastening means has a minimum diameter greater than the maximum width or diameter of the structure provided with an osteogenic or suitable coating. to become osteogenic. This allows the implant to be placed in one operation after perforating the bone or bone wall through which the structure is to pass.

According to one feature, the implant comprises a means connecting the structure to the fixing means, this means being adapted to allow relative movement between the fixing means and the structure.

According to a variant, for which the structure has an end remote from the fixing means, the implant comprises a means connecting the structure to the fixing means, this means being adapted to adapt the distance separating the free end of the structure from the fixing means.

According to a feature of one embodiment, the fastening means comprises at least one system for removably mounting on the fastening means a cover or protective cover.

For example, the osteogenic or osteogenic coating has an average thickness of at least 250 μm, advantageously at least 500 μm, preferably at least 1 mm.

The osteogenic or osteogenic coating may contain one or more additives, such as one or more bone growth factors and other substances, such as substances capable of preventing colonization of the implant or coating by bacteria, viruses, fungi, for example antibiotics, fungicides, bactericides, bone-forming substances, such as calcium derivatives, in particular calcium triphosphate or precursors thereof. The invention also relates to a kit for the preparation of an implant according to the invention, said kit comprising at least:

a structure as defined for the implant according to the invention, and at least one container containing a composition ready for use or capable of being mixed with a medium, in particular an aqueous medium, to prepare a coating as defined in the implant according to the invention.

Features and details of the invention will become apparent from the following description in which reference is made to the accompanying drawings.

In these drawings,

FIG. 1 is a side view of an intraoral implant,

FIG. 2 is a view from below of the implant of FIG. 1 without the osteogenic coating, FIG. 3 is a top view of the implant of FIG. 1,

FIG. 4 is a sectional view showing the implantation of two implants according to FIG. 1;

FIG. 5 is a view on a larger scale of an implant during its osseointegration; FIG. 6 is a side view of an intra sinus implant,

FIGS. 7 and 8 are views showing the use of the implant of FIG.

6

Figure 9 is a view of a syringe for further injection of a calcium sulfate or other osteogenic gel composition;

FIG. 10 is a view of another implant according to the invention, and

- Figure 11 is an enlarged view of a sectional detail of Figure 1 along the lines XI-XI. Description of Preferential Embodiments

The implant according to the invention is an implant that makes it possible to reduce the time it takes to set up a graft, or to avoid grafting, as well as the delay in placing the implant intended to serve as a support for the implant. implant-supported structure. The implant ensures proper placement of a bone regeneration support out of a bone cavity and placement of implants in one step. According to the invention, it will no longer be necessary to perform bone sampling or to graft material. The implant thus allows the formation of a volume of bone in and / or out of a bone cavity, particularly at least out of a bone cavity or created in a bone, but also in an air cavity.

To do this, the present invention makes use of three important elements:

Osteointegrable implants of particular structure, which constitute the first aspect of the invention; and an artificial osteogenic substrate disposed on the implant, which constitutes the second component of the invention.

According to the invention, the osteogenic or osteogenic coating comprises calcium sulphate. In particular, this coating consists essentially of calcium sulfate, preferably in its dihydrate form.

Although the calcium sulphate-based coating can quickly form a neoformed bone having the same characteristics as the bone of the subject or patient, it can be added to the coating, for example before implantation or during the preparation of the coating or by impregnation of the coating, one or more particular additives, such as OP-1 from STRYKER, 1 "OP-I being part of the" superfamily "of TGFβ (Transforming Growth Factors beta). called BMP 7 (Bone Morphogenetic Protein 7) or OP-I. associated with a carrier (carrier), allows to generate bone in large quantity and quality, from the coating of the invention rich in calcium sulfate.

The preferred implants shown in the figures have three major characteristics:

The two types of implants shown in the figures seek primary stability on bone heights that do not completely cover them; - The osteo-integrable implant parts that are not anchored first in the bone, are covered with the synthetic biomaterial osteogenic (coating) rich in calcium sulfate pharmaceutical grade; Osteointegration of the implant will be completed after complete colonization of the neoformed bone.

The coating or coating 2 is chosen to ensure good osteogenesis. The implants, in particular their structure 1, are arranged or adapted or configured in such a way that they can ideally fix the coating or coating on their surface. It is arranged on the implant in such a way that it is easily colonizable from the surrounding tissues. It is of precise composition and physical properties, but it will preferably be gelatinous or able to become gelatinous. It is the carrier of one or more active agents of osteogenic induction. This coating is firmly attached to the implant.

The coating is sufficiently strong and stable to remain attached to the implant during manipulations of its placement and the entire duration of bone colonization. This matrix or coating will be progressively replaced by the bone that will run along the implant from the surrounding tissue, as explained in more detail below. This colonization usually takes place from the neck of the implant to its apex. The coating advantageously consists of at least two distinct elements or advantageously comprises at least two distinct elements: a matrix or a binder, and particles of calcium sulphate.

Particles of calcium sulphate

The calcium sulfate particles are particles in the form of dihydrate and / or alpha hemihydrate, in particular in its dihydrate form.

The particles have a mean particle size by weight of between 10 μm and 250 μm, for example 25 μm, 50 μm and 100 μm.

The matrix or binder of the coating or coating:

Although the calcium sulphate particles are able to stick to each other after drying an aqueous suspension of calcium sulphate, it is advantageous to provide a binder or a matrix or a reinforcement to maintain the cohesion of the particles in the coating during placement of the implant in a patient.

The binder is for example a polymeric binder, in particular a cellulose derivative, such as carboxymethylcellulose. According to one embodiment, the binder is also capable of forming a gel once it is brought into contact with a medium containing water. Other possible binders are: collagen, fibrin, or recombinant compounds or polymerizable or polymerized or crosslinkable or crosslinked compounds, or a mixture thereof. This binder is also useful for the manufacture of the implant according to the invention, since it makes it possible to form a gel of a chosen viscosity as required.

The coating has a microporosity formed of pores or channels (of diameter less than 100 μm) with a mean diameter by weight of between 20 and 70 μm, and / or a macroporosity formed of pores or channels with a diameter of between 100 and 600 μm. Porosity is formed by the free spaces between the particles when the particles are attached to each other by a binder. The porosity of the coating is between 15% and 50% of the volume of the coating.

Before being implanted, the implant with its coating is advantageously brought into contact with a medium, in particular a medium prepared from patient's blood or compatible blood or a medium from the patient's blood or compatible blood. This medium is advantageously added with one or more additives, such as antibiotics, growth factors, osteogenic factors, in particular recombinant human bone growth factors.

The coating serves to give a certain volume around the structure, this volume being intended to be replaced by a roughly equivalent volume of bone tissue. The main functions of the coating are:

- to support the factors of osteogenesis;

- To be resorbed by the tissues that colonize it;

- To ensure sufficient bone volume;

- To be a support for one or more various agents, such as antiviral, antifungal, antibacterial, growth factors, etc. and their mixture;

- To ensure continuity between the neighboring tissues and itself for the bone colonization and the vascularization of the neoformed tissue.

The stability in time and space temperature coating of the human body, especially before Postéointegration, ensure perfect osseointegration of the implant. By the choice of calcium sulfate coating, it was noted that it was possible to generate a bone volume greater than the volume of the coating. Once the bone is formed, the sinus membrane is able to cover the neoformed bone if required.

When the coating is in the form of a gel, the calcium sulfate is advantageously dispersed in a collagen and / or fibrin gel, and / or of recombinant compounds or of polymerizable or polymerized or crosslinkable or crosslinked compounds, or a mixture of these, etc.

The coating may also be in the form of a hydrogel, a paste, a foam, a polymeric and / or cross-linked polymer substrate, a substrate prepared from synthetic materials and / or recombinant products, coating fluid or semi-fluid or containing fluid or semi-fluid materials, or in the form of a combination of these forms.

The coating in the form of gel or hydrogel, for example fibrin, collagen, etc. may be subjected to drying to form a porous structure in which the calcium sulfate is dispersed. The coating comprising a binder therefore advantageously has a composite structure comprising a solid phase of calcium sulphate in contact with another phase, for example porous or gelatinous, in particular a gelatinous phase in which the solid phase is dispersed.

It has been noted that the solid phase of calcium sulphate opposes detachment of the coating during its fibroblastic colonization. In particular, the solid phase will be able to oppose the detachment of the coating relative to the surface of the implant structure, due to the forces or deformation forces exerted by the retraction of the fibroblasts during their maturation. Such a solid phase based on Calcium sulphate thus makes it possible to ensure better osseointegration of the implant and / or to reduce or even prevent non-complete osteointegration of the implant or only partial implantation (or even non-osseointegration in some cases). The coating will therefore advantageously be able to avoid any detachment thereof from the implant during fibroblastic maturation.

According to an advantageous embodiment, the calcium sulphate particles present in the coating form a solid reinforcement composed of granules or balls or spheres of calcium sulphate in contact with each other, possibly with the interposition of an adherent layer. These granules, spheres and balls or other particles have, for example, a mean particle size by weight (mean diameter) of between 10 μm and 250 μm.

These granules, spheres, beads, solid particles of calcium sulphate may optionally be mixed with other solid particles, made of various solid materials, for example artificial or synthetic materials, natural materials, biological materials, optionally chemically treated and / or physically. Preferably, the material or material mixed with the calcium sulphate particles will be biocompatible, but not resorbable or weakly absorbable, in particular non-osteotransducer or weakly transducing, that is to say not able to be replaced by bone tissue. Examples of such particles are, for example, hydroxyapatite. When the coating comprises hydroxyapatite, the weight ratio calcium sulphate expressed in anhydrous form / hydroxyapatite is advantageously between 10: 1 and 2: 1. The particles, granules, spheres, etc.. the coating will advantageously be bonded to each other by means of an adhesive layer or bridges, so as to oppose the forces exerted by the fibroblasts during the fibroblastic colonization of the coating, force tending to deform the coating. The granular structure advantageously serves to support bone growth inductors of any kind. Granules, balls, spheres, etc. calcium sulphate or mixed with calcium sulphate are advantageously coated with a composition comprising at least one binding agent, preferably of a gelatinous nature. For example, the binder is of a protein nature, such as collagen, hyaluronic acid (which is a "tridimensional scaffold" or three-dimensional scaffold by itself), prothrombin, etc. The binder is also advantageously chosen to promote cell colonization.

The actual surface of the implant structure may be modified to provide good adhesion of the coating or to provide a surface for bone formation. The surface can thus be treated by electrolysis, etching, etching (acid attack, bites), etc. The surface is for example made porous, for example so as to be as such osteogenic. Thus, the support can be made at least on the surface of a hyper porous bio-material, with a pore diameter capable of rendering the surface osteogenic, for example of hyper porous titanium.

The content of calcium sulphate (expressed in anhydrous form or CaSO ₄ ) of the dry or free water-free coating is advantageously between 50 and 80%, the coating being constituted for example essentially consisting of calcium sulphate in dihydrate or alpha hemihydrate form. .

The average thickness of the coating is advantageously from 2 to 4 mm. The total volume of coating is advantageously greater than the volume of the structure around which bone is to be formed.

The calcium sulphate coating has a pumping effect on the bone cells, thus favoring the colonization of the coating and its transformation into bone tissue. The coating also serves as means for protecting the titanium structure, in particular against external contaminations, bacterial, fungal, viral and others. In addition, the use of calcium sulfate in orthopedic surgery is well known.

It has thus been noted that calcium sulphate was a suitable material for the formation of bones in the jaws, in particular the upper jaw, even if bone height is very low or almost non-existent, in particular with a portion extending into an air cavity of the sinus. It has furthermore been noted that the placement of an implant according to the invention having a coating based on calcium sulphate, in a sinus graft, allowed ossification of the coating and the sinus graft.

The coating is advantageously applied to the spray structure, in one or more steps, followed by one or more drying steps. Optionally after each spraying step, the partial coating is dried.

Addition of osteogenic factor (s) in the coating

Although the application of the calcium sulfate-based coating is already very rapid and reliable without the addition of particular osteogenic factors, it may be useful in particular cases to add to the coating or soak the coating with one or more osteogenic factors. additional.

These additional factors of osteogenesis of the coating can be of several types and of several origins, but they will be mainly from genetic engineering (recombinant human bone growth factors, etc.). All these factors will be called over time to be modified, by their nature, their concentration, their process of preparation, etc., according to the evolutions of the science. For example, only one osteogenic factor could be added to the coating, such as OP-1, but it could be that over time, for whatever reason, other osteogenic or combinations of osteogenic factors, or even a combination of osteogenic factors with other elements later prove more efficient.

The addition of osteogenic factors makes it possible to save patients with difficult osseointegration profiles one or more expensive hospitalizations, pain and unpredictable postoperative complications, while sparing at least the six months necessary for engraftment, since it no longer has any reason to be thanks to the implant according to the invention.

Generalities on edentulism:

The implant of the invention finds applications in the formation of bones at various places in the human body, but in particular in the field of dental prostheses and the prosthetic fitting of maxillary atrophies. It allows patients who were not candidates for the sinus lift, to be paired quickly and cheaply.

The total edentulousness of the maxilla:

The total edema of the maxillary is a major handicap for patients who suffer from it and is widespread in the world. The number of potential candidate patients is unfortunately increasing day by day. The loss of the dental organ mainly induces the disappearance of the periodontal bone, a melting of the maxillary bone and pneumatisation of the maxillary sinuses. After a few years wearing conventional removable prostheses, it is not uncommon to find patients with an almost flat maxillary, reduced to the thickness of a sheet of cigarette paper, on which conventional prostheses no longer hold. In the posterior segment, where the molars and the second premolar were, the thickness of the maxillary bone may be less than one mm thick. This situation, conventionally, requires sinus grafts, if one wishes to put dental implants. This discourages many patients and practitioners from using implantology. These patients are at a standstill while their situation is difficult to live with.

In this case, current osteointegrative implants, by their design and shape, require that transplants be performed several months before placement.

Classical schema of maxillary grafts:

It requires one (or two) elevations of the floor of the maxillary sinus, or sinus lift, followed by a waiting period of six months, for the taking of the graft. After this time only, the implants can be placed. The osteointegration time of the maxillary implant is approximately six months, after which the patient can be paired. This is a total of a minimum of one year, between the placement of the first graft and the wearing of the prosthesis. The present invention will reduce these waiting times by rapid and reliable colonization of the coating of the implant according to the invention, this even if a portion of the coating is in an air cavity.

The sinus lift

This surgical procedure involves performing a sinus filling by grafting elements that will turn into bone. In the case of the present invention, the placement of the implant will serve as placement at the required location of a structure with a suitable coating to quickly and reliably form the bone, the implant being quickly coated with d in order to allow the patient to be quickly fitted with new teeth or a crown or other dental appliances. Partial edentulousness in the maxilla:

When one, two, or even three upper molars on the same side are missing, with or without premolars, we often find ourselves faced with a lack of bone height. There are often only two to five millimeters of bone height, or less, or a little more. This is often insufficient to implement implants according to conventional methods: the minimum height allowed is generally 10 to 12 mm. We are thus in a situation similar to that described above, with regard to total edentulism: we must perform sinus grafts.

In the case of the present invention, the placement of the implant will serve as placement at the required location of a structure with a suitable coating to quickly and reliably form the bone, the implant being quickly coated with d in order to allow the patient to be quickly fitted with new teeth or a crown or other dental appliances.

The implant of the invention:

The implant of the invention is an implant system easy to use, industrially feasible and reproducible clinically, to benefit a maximum of patients, a system for rapid osteogenesis and controlled extra bone, that is to say in a volume located out of an existing bone or to increase the thickness of bone on which the implant is positioned, and this even in an air cavity. This makes it possible to prevent the fixation of the implant from being performed only from an existing bone, that is to say, be limited only by the mechanical characteristics of the existing bone part in which the implant is fixed.

The use of pharmaceutical grade calcium sulfate in the coating according to the invention, in particular in dihydrate form, makes it possible to simplify the implant placement procedures, while ensuring optimal safety. The implant according to the invention is particularly suitable as an implant for the upper jaw, since it allows, thanks to the choice of calcium sulphate, to ensure bone formation even for part of the structure located outside the bone. , especially in a sinus cavity, and this even if the implant is not in direct contact with bone, but is placed only in a sinus graft.

According to the invention, the structure of the preferred implants is profoundly modified with respect to all existing implanted implant systems. They have their own characteristics, which can not be applied to conventional implants.

According to the invention, two types of preferred implants have been imagined:

1 °: Implants to be placed by the endobuccal route; - 2 °: The implants to be placed by the endosinusian way.

These two types of implants address two essentially different situations:

- The endobuccal implants can be placed for residual bone heights of at least 4 to 5 mm, for example up to 10 or 12 mm or more;

- Implants to be placed endosinusically can only be placed if the residual bone height of the sinus fundus is less than about 3 mm.

This will make it possible to pair by the invention the majority of patients concerned by maxillary atrophies due to edentulism.

General information concerning the implants according to the invention:

The preferred implants according to the invention, represented in the figures advantageously have the following particularities: 1 °: The surface states of the osteointegrable parts of the implants or structure provided with the coating have the same characteristics as the implants currently marketed, and are advantageously treated to be porous or have one or more cavities or attachment zone; - 2 °: The parts of the implants used to receive the implant-supported structures are standardized, and able to receive the materials marketed by the manufacturer, in order to avoid errors and reduce the number of parts;

- 3 °: The structure provided with the osteotransducer coating is contoured to anchor the coating optimally, promote bone colonization and ensure excellent anchoring of the structure with the bone tissue once it is formed.

Implants of the endo-oral route (Figure 1)

The implants of the oral tract are put in place by this same path, just like the other implants. According to the invention, the implants have been configured to limit the opening of the sinus cavity and minimize the surgical procedure, while ensuring rapid formation of bone. As mentioned above, the part or platform that is used for fixing the implant-borne structures is standardized. This platform has for example the same characteristics as those of other implants marketed by the manufacturer, this to limit the number of parts to use, and to reduce costs.

The osseointegrable part, according to the invention is clearly modified compared to conventional implants: according to the invention, it comprises three particularities: - 1 °: a screw fixing 3 of the implant to the bone (ensuring its stability primary and positioning of the implant);

- 2 °: A part or structure 1 provided with a coating based on calcium sulfate (2); - 3 °: grooves and / or bone regeneration channels or capable of inducing bone regeneration on the walls of the structure 1, these grooves and / or channels being provided with or without a coating promoting colonization of cells inducing bone formation and / or transfer of such cells to the coating of structure 1.

The grooving 6 of the structure 1 of the implant, from the emergence to the apex, allows rapid bone colonization of the calcium sulfate-based coating from the wellbore through the channels 3B.

Advantageously, the channels 3B can be filled, partially or substantially completely with bone, during the positioning of the implant. This bone (in the form of particles or pieces) in the channels will colonize the coating 2 to replace it with living bone.

The lining 2 of the implant of the endobuccal way.

The coating based on calcium sulfate is covered with a protective layer 20. After removal of the protective layer, the implant is targeted in the perforated hole in the bone wall. According to a variant, before screwing the implant into the bone wall, the coating is soaked in an at least partially aqueous medium, for example in patient's blood, in which the medium is advantageously added an antibiotic and / or an anti-coagulant agent. and / or one or more bone growth factors. The implant is able to be fixed on bone heights of about 5 mm or more. This residual bone height makes it possible to ensure primary stability to the implant by means of the thread 3A of the fastening means 3 screwed into an osseous bone wall covered with the oral mucosa MB (see FIGS. 4 and 5). The remainder of the implant (structure 1 and coating based on calcium sulphate 2 optionally provided with a compatible organic protection layer) emerges freely in the sinus cavity SN. The 2 will be colonized by the bone, so as to form an additional bone volume, this additional bone volume will constitute a secondary stability for the implant, this secondary stability being advantageously far superior to the primary stability, once the additional bone volume achieved. Thus, patients in "borderline" situations can be paired as simply as patients with sufficient bone heights, all the more so that osteointegration or bone formation from the lining will be rapid.

The preferred implants represented according to the invention (which are for example mono-block) consist essentially of three distinct parts (see FIG. 1):

- The fastening means with screw thread 3;

- The bulb or structure 1; and

- The coating based on calcium sulphate 2.

The coating may optionally be provided with a protective layer for the coating 2. This outer coating (for example 2A in FIG. 1) may have a thickness, for example between 10 μm and 1000 μm, for example from 100 μm to 800 μm, and or particular properties (porosity, etc.). This outer coating is intended to protect the coating 2 in contact with the bulb 1, for example during the placement of the implant. This coating provides, for example, mechanical and / or biological protection (against bacteria, against fungi, against viruses, etc.) and / or contains elements capable of ensuring good bone tissue development. This outer coating is for example porous (porosity varying for example over the course of time between zero or low porosity towards a large or complete porosity), biocompatible and / or bioabsorbable, and / or with controlled or delayed release of one or more agents. , such as bone growth factors, antibiotics, antifungals, antivirals and their mixtures. The coating 2 is applied to the surface of the bulb or structure 1, said surface being advantageously treated to have a surface porosity.

The fixing means 3:

The fixing means advantageously comprises a screw thread 3 A intended to provide sufficient primary stability to the implant during its osseointegration. This thread is traversed by channels 3B which open into the longitudinal grooves 6 which go from collar at the apex of the structure or bulb 1. The thread is preferably not provided with a coating of calcium sulfate. The thread advantageously extends over a length (L3) of 4 to 7 mm. The channels 3B extend along an axis C parallel to the central axis A of the structure and to the direction of the grooves 6. The channels 3B are advantageously at least partially filled with osteogenic gel or a composition based on sodium sulfate. calcium.

The 3B channels may not be completely filled with osteogenic gel or calcium sulfate. These channels present or form then a free volume to receive bone debris and blood factors during the establishment of the implant according to the invention. This free volume will be particularly interesting when the screw is of the tapping or self-tapping type. FIG. 11 shows in section a detail of the screw 3. As can be seen in this figure, the outside diameter of the thread 3 A increases from its adjacent end of the structure 1 towards its end carrying the flat 4. channel 3B is partially formed in the net, so as to define in the thread a series of teeth or tapping edges 3 E having a cutting edge located at a radius substantially corresponding to the average radius of a round of thread that follows this cutting edge. This leading edge thus digs a groove in the bone, which once allows the groove formed to facilitate the attachment of the screw. The leading edge is further profiled so that bone debris formed by the cutting edge 3E is directed to the channel 3B. The fixing means 3 advantageously comprises on its end opposite to that facing the bulb or structure 1, a round plate 4 carrying a fixing bolt 5 for the placement of a prosthesis and to ensure the screwing of the means 3 in the bone . ^'

The channels 3B advantageously have a flared shape towards the structure 1. These channels are filled (partially or completely) or not with material capable of being colonized by bone cells or capable of allowing the passage of bone cells towards the coating 2.

The bulb or structure 1:

It is the part that serves as support for the coating 2.

This bulb or structure 1 has a shape adapted to receive the coating 2 and secure it. This form has horizontal and vertical grooves 6 (for example annular) (that is to say parallel to the central axis of the structure 1 and perpendicular to this axis), intended to promote bone colonization (FIGS. 4 and 5). ). Part of the bulb or structure 1 provided with a coating 2 may emerge totally or partially in the sinus, that is to say form partially or totally bone extra bone. The shape of the bulb or structure 1 is subject to many modifications to facilitate the anchoring of the coating and its colonization.

Example No. 1: Placement of an implant of the type shown in Figure 1 (having channels 3B) with a diameter D of 5 mm and a total length of 12 mm; the bone height H of the sinus bottom is 5 mm.

The fastening means has a height L3 of about 5 mm, height on which the means is provided with a screw thread 3A. The implant set up, the thread will be completely covered with bone and the coated part will emerge completely into the cavity sinus of 12 - 5 mm, ie 7 mm (length L). Colonization of the calcium sulfate coating will be initiated in the vicinity of the attachment means. This colonization will then be rapid until the far end of the fixing means 3 by pumping the cells into the coating 2. (see FIG. 4, implant II)

Example 2: Placement of an implant 12 (see Figure 4) as shown in Figure 1 a diameter D of 5 mm and a total length of 12 mm; the bone H height of the sinus bottom is 7 mm. The fastening means has a height L3 of about 5 mm. The calcium sulphate coating 2 is located partially in the bone portion to a height of 2 mm, and the remainder of the structure 1 provided with the coating 2 emerges about 5 mm into the sinus. This is advantageous because the two mm of coating located in the intraosseous portion will be easily colonized by the bone. In this case, the channels 3B of the thread will have an accessory role in the colonization of the coating. The coating 2 which is on the bulb 1 of the implant forms an outer casing surrounding the bulb 1 of the implant, this casing having a diameter smaller than the diameter D of the fixing means 3, so that it can be introduced into the wellbore without being damaged.

The vertical grooves 6 (parallel to the central axis of the structure 1) are arranged substantially along the entire length of the bulb 1 of the implant. The channels or gutters 3 are arranged substantially the entire length of the fixing means, said channels or gutters 3 B forming a passage between an end facing one or grooves 6, and an open end facing a bone part in which the means of fixation is placed. The horizontal splines are annular and form junctions between the vertical splines. The flutes 6 (vertical and horizontal) are filled with calcium sulphate. It is from the face of the coating 2 in contact with the bone tissue that the colonization of the intra-sinus coating will take place. The number of grooves or channels is for example between 1 and 5, 3 being considered optimal. The number of grooves 6 may be different from the number of channels 3B. The number of grooves can be different from the number of channels 3B. During the placement of the implant, the 3B channels can be used incidentally tap. It is along the flutes 6 that osteogenesis or bone formation will mainly take place. The formation of bone will also be advantageously limited substantially to a volume close to the flutes 6, for example to a volume formed around the flutes corresponding to 1 to 10 times the volume of coating based on calcium sulfate covering the flutes or filling the flutes .

Bone stem cells colonize the coating from living tissue. In implants of the endobuccal approach, the sinus mucosa is relatively respected, and the covering tissues of the maxillary bone can not come into contact with the osteointegrate parts. Colonization has no choice but to start from the wellbore or hole in which the attachment means 3 is placed. To promote colonization, grooves are placed over the entire length of the implant. These grooves facilitate the colonization of the coating, the wellbore or hole in the bone part in which the fixing means is placed, towards the apex of the implant. The coating based on calcium sulphate advantageously has a sufficient volume to ensure sufficient anchoring for the loading of the implant and ensure its durability of activation by a prosthesis.

Another type of bulb or structure may have a series of grooves 6 substantially parallel to the longitudinal axis of the bulb 1. The implant comprises a fixing means 3 with a channel 3B or channels 3B, as described in the form embodiment of Figure 1, 5, etc.

The flutes 6 have a narrow portion on the surface of the bulb and a wider portion remote from the outer surface of the bulb. The narrow part has in section transverse (in a plane perpendicular to the longitudinal axis of the bulb 1) a substantially rectangular shape, while the inner portion has a substantially circular shape, the diameter of the inner portion being larger (for example at least twice as large ) the width of the narrow part. The flutes 6 extend from the fastening means to the free end (see FIG. 6).

These internal notches also form anchor points for the calcium sulphate layer optionally placed on the surface.

Dimensions and sizes of implants:

Implants are characterized for the practitioner by their length and diameter. Implants of the endobuccal route may be characterized or classified according to one or other of the following parameters:

Their total length (L + L3);

The length of the thread (L3);

The length of the bulb (L);

- The diameter of the implant (D); - The size of the channels;

The number of channels;

- The minimum equivalent diameter of structure 1;

- The type of coating based on calcium sulfate 2;

The concentration of tissue factor in the coating 2; - The concentration of various additives present in the coating;

- Etc.

The total length of the implant is for example 8 to 18 mm. Their optimal length is between 12 and 15 mm. The length of the thread is from 4 to 10 mm. The ideal length is 5 to 7 mm. The bulb extends over the rest of the length. The diameter of the implant is taken into account at the level of the thread, the diameter at the bulb (structure without its coating osteogenesis) being less important to leave a free volume to a coating layer located inside a cylindrical volume of diameter smaller than the diameter of the thread, so as not to damage the coating during the placement of the implant structure, in particular the extra-osseous placement of this structure. The diameter of the implant in the vicinity of the fixing means is 3 to 7 mm, but a diameter of 5 to 6 mm is preferred.

Implant placement by the endobuccal route:

The implants of the oral tract are set up exactly like conventional implants, using the same instrumentation or possibly a specific instrumentation, without additional manipulations, which is an important asset.

Classically, the oral mucocateriac is clear, and a series of drills will create a trans-osseous channel. Unlike what is done with today's conventional systems, the operator will traverse the full thickness of bone to end up in the sinus cavity. These operations carried out, the implant is set up, like any system currently marketed. If the bone height of the ridge is at least 4 to 5 mm, a primary stability of the implant is provided by the fixing means 3. An essential difference with the existing systems is that the implant according to the invention emerges in the sinus.

A lid 10 is placed above the fixing means to cover the surgical site and close it. This lid 10 makes it possible to limit the quantity of oral mucosa pushing above the means 50 able to serve as an attachment base for the prosthesis and makes it possible to avoid having to remove oral mucosa in contact with this means 50. 5) During osseointegration of the part of the implant in the bone and in the sinus, the calcium sulphate coating will be invaded and replaced with bone. After less than 6 months, the implant is completely osseointegrated and can quickly be loaded according to conventional techniques.

The bone colonization comes from the wells or channels 3B present in the fixing means, along the bleedings soaked bone chips formed during tapping performed placement of the implant. For this reason, the minimum length of the well is advantageously at least 4 to 5 mm.

Intra-sinus implants (Figures 6 to 8):

These implants are of particular shape. Osteoinduction is produced by the stem cells of the patient himself.

Their osseointegrable surface is completely exo-osseous to placement. Their osseointegrable surface is completely covered with a layer of calcium sulphate intended to be entirely colonized by the neoformed bone. Advantageously, one or more factors for induction of osteogenesis are added to the layer.

They have a configuration that distinguishes them from the implants generally placed on the market today:

- They have no screw on their surface to fix them in a hole formed in the bottom of the sinus;

- They are extensively grooved from the neck to the apex of the implant;

Indeed, the grooves must lead colonization by bone cells or osteointegration of the sinus bottom to the implant apex, and incidentally by the soft tissues that come in contact with it through the fenestration of the sinus lateral wall. The bone growth or osteointegration takes place in a sufficient volume, to ensure a correct vascularization of the neoformed bone; the coating is firmly anchored. The osteointegrable surface is preferably as large as possible. Where appropriate, the calcium sulfate coating will extend into a bone graft.

The practitioner will have at his disposal a syringe 200 in which will be a gel containing one or more osteogenic factors or a fluid mixture (possibly after mixing two separate components) capable of forming a gel containing one or more osteogenic factors. This gel will be complemented to promote the bone colonization of the coating or coating 2 from the surrounding tissues and to form a larger bone volume. This gel will advantageously also contain calcium sulphate.

The implant will preferably be of the retentive type for the calcium sulphate-based coating and will therefore have one or more protuberances 7. (FIG. 6) The upward ribbing of the structure 2 (FIG. 6) and the recess on the bottom will preferably be maximized because o It is in the volume of the ribbing and recess, that the bone colonization of the coating and osseointegration will take place; o The ribbing should have a sufficient volume

In contrast to endobuccal implants, the calcium sulphate-based lining of intra-sinus implants will be colonized from the inner lining of the maxillary sinus and surrounding soft tissues, prolapsing in the sinus cavity. It is well known that stem cells arrive at the site through the bloodstream.

Shape of intra-sinus implants: They are of a particular form. It will preferably favor the fixing of the coating optimally; will allow easy colonization of the coating by the bone and ensure sufficient osseointegration for stable loading over time. The bone volume should be sufficiently large and properly vascularized.

Length and diameter of intra-sinus implants:

They advantageously have a length of between 8 and 18 mm, and a diameter which is 3.8 to 7 mm.

With respect to the implant shown in FIG. 1, the structure 1 of FIG. 6 has a plate 11 intended to bear on the inner face FI and comprises a means 12 adapted to cooperate with a fastening and covering screw 13. This screw has a threaded rod 14 whose end is engaged in a threaded hole of the means 12. The hole 15 formed in the wall of the sinus has a diameter greater than the diameter of the rod 14. The coating 2 covers the lateral sides of the plate 11 forming a slight bead B extending to a level Nl greater than the level N2 of the plate 11 intended to bear on a bone wall or on the inner face of the bone part, so as to ensure colonization of the cells via the contact facing 2 - bone face FI. To ensure the formation of an even larger volume of bone, it is possible to inject in the vicinity of the implant 1 a gel G or a solution able to become a gel, this gel containing one or osseointegration factors . (See Figure 8) To avoid colonization of the plate 11 or at least the adjacent portion of the means 12, a ring 40 is attached to said plate 11 or is placed on said dish. This ring 40 is advantageously made of a friable material and comprises one or more agents opposing the colonization of the plate 11. (see FIG. 6)

Intra-sinus implant placement: The mucosa of the site of the intervention is taken off. An opening frame 15 is cut into the lateral wall 16 of the maxillary sinus while respecting the underlying sinus mucosa. The sinus bone window is pushed upwards by pushing back the sinus mucosa. This mucosa is detached from the sinus bottom 17. The lining 18 of the alveolar ridge is detached to palatine to clear the alveolar ridge. A drill is used to drill the hole 15 corresponding to the place where the implant 1 is to be placed. The operator places the implant 1 with its coating 2 in the sinus cavity and fixes it on the screw 13 (cover screw) which is in endo-oral. The screw 13 or cover-screw is carefully tightened, without completely crushing the low sinus bottom. This tightening will ensure a good contact between the bead B and the bone of the sinus bottom bottom 17. The operator can at this time add to the gun or in any other way a complement of gel or osteogenic composition, to allow the bone colonization of the bone. implant from the surrounding tissues, which will increase the integration of the implant.

The primary stability of this implant is found on the thin residual bone layer of the sinus bottom 17.

In this use, it is preferable that the implant is immediately covered with a coating based on calcium sulfate, to limit handling and ensure a flawless coating of the implant.

The syringe of osteogenic gel or of osteogenic product which may be gelable or capable of becoming a gel:

It may be useful for the practitioner to place the bulb liner in increasing the amount of osseointegrable material, for example from a calcium sulphate composition or gel around the implant or around its liner, to increase the amount of bone around the implant and promote the bone colonization of its coating from the surrounding tissues. He will have for this purpose a syringe containing a calcium sulfate gel or a composition capable of forming an osteogenic gel. The syringe may be of the type with two or more compartments with a mixing system of the contents of the different compositions contained in the front compartments, in particular just before its injection. This gel will be used to establish bridges from sites suitable for regeneration. These bridges thus created will lead bone cells and bone to the coating of the implant. This then makes it possible to provide additional bone cells for the osteogenesis of the coating and to increase the chance of obtaining complete or almost complete osteogenesis of the coating 2. The needle 151 of the syringe 150 (see FIG. a maximum diameter of between 3 and 5 mm, with a diameter of the inner passage of between approximately 2 and 4 mm. The free end of the needle is curved. The volume of gel contained in the syringe is for example between 0.5 and 3 cm ³ . To limit the losses of products on the walls of the syringe, the diameter of the syringe will be limited for example to less than 1 cm, in particular less than 0.7 cm. In the embodiment shown, the syringe has an inside diameter corresponding to the inside diameter of the needle 151, so that the piston 152 is able to slide in the needle and push substantially all the gel present in the needle. syringe and in the needle. According to an advantageous embodiment, the needle 151 and the body of the syringe form a single piece.

The release of intra-sinus implants:

During Postéointegration of Structure 1, the oral mucosa covers the screw 13. To place an intermediate support for prosthesis on the implant, the mucosa covering the screw 13 is removed. This intermediate support can either be placed directly on the screw 13, or placed on the implant. Once the support is placed, it is possible to take the impressions of the superstructure that must be attached to the implant. Figure 10 shows an implant similar to that of Figure 1, except that the bulb 1 has three grooves 30,31,32 extending in a plane perpendicular to the central axis AA of the implant. The grooves have a diameter that is reduced to the closer we get to the free end.

The calcium sulphate coating of the structure may be fixed by physical and / or chemical and / or mechanical retention means, or of any other nature, particularly a combination of such means. This coating can be prepared by heating. This coating can be held in place by means of a lattice structure, or braided, or knitted or woven, for example to polygalactin 910 type mesh, etc. or made of any absorbable thread, or thanks to a porous support. In the case of a porous support, a liquid composition may be incorporated into the support. In particular, according to the invention, the coating 2 is in the form of a gel or a pasty structure covered with an overcoating (mono or multilayer) or not. In this gelatinous form, it responds advantageously to several essential characteristics:

- It must have physical characteristics that hold it in place on the parts of the implant provided for this purpose, in time and space; - It can not deform at body temperature;

- Being easily colonizable by the tissues intended to replace it, this includes that it must be easily colonizable by the bone tissue which will replace it (it can not be a barrier to colonization;

- It is intended to be totally eliminated by the body. The coating 2 is intended to be colonized biologically by the patient's bone tissue, on which the invention has been put in place.

The coating is advantageously provided with an overcoating or an outer protective layer as described above. This overcoating is for example slower resorption than the coating and has controlled release properties for one or more growth factors, one or more antibiotics, one or more antifungals, etc. and their mixtures.

The implants according to the invention may be made of titanium or any other material or assembly of materials of any nature whatsoever, osseointegrable.

The invention makes it possible to place implants in bone walls considered to have insufficient bone thickness for conventional implants. The implants are intended for partial recovery by bone tissue from the subject to placement. The implants conventionally put in place on the market today, must be completely covered with bone, while those described according to the invention must not be.

The implants advantageously have a shape with a modified surface so that the coating can be fixed on the parts that support it.

The implant advantageously has a shape intended to promote the colonization of the coating in an optimal manner, and is configured to promote bone colonization, and the anchoring of the neoformed bone, to ensure osteointegration, compatible with its implementation. in prosthetic loads.

The implants according to the invention shown in the figures are not intraosseous during their placement. They will see their coating be totally or partially replaced by bone tissue from the surrounding tissues.

For placement of an implant according to the invention comprising means for attachment to a bone wall, it is necessary to drill a hole in a bone wall. To do this, it is possible to use known type of motorization devices with one or more drills of the known type. The invention also relates to a kit for the preparation of the implant just before implantation.

The kit comprises: a titanium implant comprising a bulb 1, said implant not having a calcium sulfate coating,

a container comprising calcium sulphate and carboxymethyl cellulose,

a syringe containing a quantity of mixing liquid, such as sterile pyrogen-free water, and a spatula, and possibly a bottle containing an antibiotic.

The container containing the solid particles of calcium sulphate is opened and a quantity of water is added to form a gel or paste. This mixture is mixed using the spatula to make it homogeneous. The antibiotic is eventually added.

This homogeneous mixture is applied to the titanium bulb 1.

In one possible application form, once the mixture is made homogeneous, it is mixed with crushed bone particles of the patient or a compatible patient.

Still in another possible embodiment of the kit, the bulb of the titanium implant is provided with a precoat based on calcium sulfate. A wet layer of calcium sulphate (with or without antibiotic and / or ground bone) is then applied to this calcium sulfate precoat.

Claims

claims

1. Implant comprising a structure (1) provided with a coating (2) or osteogenic layer or capable of becoming osteogenic, said implant advantageously comprising a positioning means (3) adapted to cooperate with a living bone part so as to ensure a positioning of the implant relative to the living bone portion, said positioning means then being adapted to be in contact with at least one zone of a bone part or able to become bone, characterized in that the osteogenic coating or adapted to becoming osteogenic includes calcium sulfate.

2. Implant according to claim 1, characterized in that the osteogenic coating or capable of becoming osteogenic comprises calcium sulfate in its dihydrate form or alpha hemihydrate.

3. Implant according to claim 1 or 2, characterized in that the osteogenic or osteogenic coating comprises calcium sulfate, preferably in its form dihydrate or alpha hemihydrate, mixed with a binder advantageously bio-resorbable.

4. Implant according to claim 3, characterized in that the binder comprises at least one polymeric binder, in particular a biopolymeric binder, preferably a cellulose derivative.

5. Implant according to any one of the preceding claims, characterized in that the osteogenic or osteogenic-forming coating comprises from 5 to 95% by weight, advantageously from 10 to 85% by weight, preferably from 25 to 75% by weight. weight of calcium sulphate expressed as anhydrous or CaS04 relative to the dry weight of the coating or weight of the free water-free coating. 6. Implant according to any one of the preceding claims, characterized in that the osteogenic coating or capable of becoming osteogenic comprises calcium sulfate in the form of particles having a mean particle size by weight of between 1 .mu.m and 1 mm, advantageously between 5 .mu.m and 750 .mu.m. preferably between 10 μm and 250 μm.

7. Implant according to any one of the preceding claims, characterized in that the osteogenic coating or capable of becoming osteogenic consists essentially of calcium sulfate in its hemihydrate and / or dihydrate form.

8. Implant according to any one of the preceding claims, characterized in that the osteogenic coating or capable of becoming osteogenic has a porosity comprising pores with a mean diameter by weight of between 10 nm and 1000 μm, advantageously between 1 μm and 800 μm, of preferably from 10 μm to 600 μm, in particular from 15 μm to 100 μm for micropores and between 100 and 600 μm for macropores.

9. Implant according to any one of the preceding claims, characterized in that the coating comprises a non-resorbable or weakly absorbable material, preferably in an amount between 0.1 and 25% by weight, preferably from 0.5 to 20% by weight. % by weight, based on the total weight of the coating comprising calcium sulphate in dry form or free of free water.

10. Implant according to claim 9, characterized in that the non-resorbable or weakly absorbable material is a non-osteotransducer or weakly transducing material. 11. Implant according to claim 9 or 10, characterized in that the coating comprises hydroxyapatite.

12. Implant according to claim 11, characterized in that the calcium sulphate weight ratio expressed in anhydrous form / hydroxyapatite is between

20: 1 and 1: 20, advantageously between 15: 1 and 1: 2, preferably between 10: 1 and 2: 1.

13. Implant according to any one of claims 9 to 12, characterized in that the non-resorbable or weakly absorbable material, in particular hydroxyapatite, is in the form of particles having a mean particle size by weight of between 1 .mu.m and 1 mm. advantageously between 5 μm and 750 μm, preferably between 10 μm and 250 μm.

14. Implant according to any one of the preceding claims, characterized in that the coating is substantially free of free water.

15. Implant according to any one of claims 1 to 13, characterized in that the coating comprises from 5 to 200% by weight of free water relative to the weight of the coating free of free water, preferably from 15 to 100% preferably from 20 to 75% by weight of free water.

16. Implant according to any one of the preceding claims, characterized in that the coating comprises at least one bone growth factor.

17. Implant according to any one of the preceding claims, characterized in that the coating comprises an antibiotic. 18. Implant according to any one of the preceding claims, characterized in that the coating comprises phosphate di calcium and / or calcium carbonate and / or hydroxyapatite and / or tricalcium phosphate.

19. Implant according to one of claims 1 to 18, wherein the structure provided with a coating or osteogenic layer is adapted to ensure the formation of bone in an extra-bone cavity, in particular in an air cavity.

20. Implant according to one of the preceding claims, characterized in that the osteogenic or osteogenic coating or layer is adapted to form a bone volume at least equal to 50% of the volume of the structure (1), advantageously at least equal to once the volume of the structure.

21. Implant according to any one of the preceding claims, characterized in that the positioning means (3) has at least one channel or passage (3B) adapted to ensure bone development from the bone portion to the structure provided with a osteogenic coating or able to become osteogenic or to receive crushed bone containing cells able to colonize the coating.

22. Implant according to claim 21, characterized in that the positioning means (3) comprises at least two separate channels or passages adapted to ensure bone development from the bone part to the structure provided with an osteogenic or adaptable coating. osteogenic.

23. Implant according to claim 22, characterized in that the channels or passages (3B) are placed substantially symmetrically with respect to the fixing means. 24. Implant according to claim 22, characterized in that it comprises three channels or passages (3B) placed symmetrically with respect to the positioning means.

25. Implant according to any one of the preceding claims, characterized in that the positioning means (3) is a fastening means having a substantially cylindrical or substantially frustoconical outer face provided with a thread (3A) adapted to cooperate with a thread of a hole formed in the living bone part.

30. Implant according to the preceding claim, characterized in that the channel or channels extend on the outer face along an axis substantially corresponding to a generatrix of the face.

31. Implant according to the preceding claim, characterized in that at least one channel or passage has a minimum cross sectional passage of more than ¹ mm ² , preferably more than ² mm ² , preferably at least 10 mm ² .

32. Implant according to the preceding claim, characterized in that the passage section of the channel or channels corresponds to at least 5%, preferably at least 10%, preferably at least 15% of the average cross section of the substantially cylindrical face or frustoconical on the surface of which are formed the channel or channels.

33. Implant according to any one of the preceding claims, characterized in that it has a maximum diameter or width of less than 15 mm and a total length of less than 30 mm.

34. Implant according to any one of the preceding claims, characterized in that the structure provided with an osteogenic coating or capable of becoming osteogenic has one or more grooves (6) or grooves to promote bone colonization, these grooves (6) advantageously forming an extension of a passage or channel (3B) of the fixing means (3), while the grooves advantageously extend perpendicular to the central axis of the implant.

35. Implant according to any one of the preceding claims, characterized in that the fixing means (3) has a minimum diameter greater than the maximum width or diameter of the structure provided with an osteogenic coating or capable of becoming osteogenic.

36. Implant according to any one of the preceding claims, characterized in that it comprises a means connecting the structure to the fixing means, this means being adapted to allow relative movement between the fastening means and the structure.

37. An implant according to any one of the preceding claims, wherein the structure has an end remote from the fixing means, characterized in that it comprises a means connecting the structure to the fixing means, this means being adapted to adapt or control the distance separating the free end of the structure relative to the fixing means.

38. Implant according to any one of the preceding claims, characterized in that the fixing means comprises at least one system for removably mounting on the fastening means a cover or protective cover.

39. Implant according to any one of the preceding claims, characterized in that the osteogenic or osteogenic-capable coating has an average thickness of at least 500 μm, advantageously at least 1000 μm, preferably at least 2 mm. 40. Implant according to claim 22, characterized in that the coating is formed of particles which, by not taking into account their internal pore volume and their internal volume, in the case of hollow particles, form a corresponding inter-particle free volume. to more than 30% of the total volume of the coating (volume of the particles + volume of the binder), preferably more than 50%, in particular more than 75%, more specifically 80 to 95% of the total volume of the coating.

41. Kit for the preparation of an implant according to any one of the preceding claims, said kit comprising at least: - a structure as defined in any one of the preceding claims, and at least one container containing a composition ready to use or being capable of being mixed with a medium, in particular an aqueous medium, to prepare a coating as defined in any one of the preceding claims.