MXPA01003730A - Method and device for preparing a dental implant by immersion in a mesenchymal cell culture - Google Patents

Abstract

The invention concerns a method for making a dental implant consisting in:preparing an implant consisting of a radicular part and a coronal part and made from a biocompatible inert material corresponding in shape to an extracted tooth;immersing said implant radicular part in a culture of undifferentiated mesenchymal cells, in a culture medium whereof the composition enables the differentiation in cementoblasts and in fibroblasts, for a duration sufficient for said differentiation, for the cement blasts to adhere on said radicular part, for a first layer of cement and a alveolar-dental ligament attached to said cement to be formed;collecting the implant bearing differentiated tissues fixed on its radicular part.

Description

METHOD AND DEVICE FOR PREPARING A DENTAL IMPLANT BY IMMERSION IN A MESENQUIMATOSO CELLULAR CULTURE The present invention relates to integrated periodontium dental implants, comprising cement on the surface of the root and a ligament for connecting the cement in the bone socket, as a natural tooth. The invention relates to a method of preparing said implant for contacting the implant with undifferentiated mesenchymal progenitor cells under culture conditions that allow the adhesion of cementoblasts and the alveolar-dental ligament over the root portion of the implant and the implant. implantation of the implant by all cells of differentiated tissues. The invention relates equally to a cell culture device for the preparation of a dental implant. Finally, it refers to a method to replace the teeth lost or compromised by the implants on those that are inserted by an appropriate cell culture technique, the cells and biological tissues that allow then to obtain a healing in the mouth by cement and ligaments between the osseous alveoli and the implanted roots. Dental transplants and reimplantations are practiced after several decades and numerous techniques have been described. Among the techniques that resort to implantation, which are essentially practical to date are the following: a) Prostheses on integrated osseous implants that are the artificial roots in titanium that are stabilized by bone ankylosing. The force of mastication is transmitted to the bone without any depreciation, due to the absence of alveolar-dental ligament which is an important factor of protection of the teeth against impacts, overloads and risks of fracture, b) Transplants or other grafts dental, that do not have the disadvantages of the approximate precedents but that need the extraction of a donor tooth available and generally not functional. Prior to the description of the present invention, a reminder of the physiological conditions of the natural tooth connection is necessary. The tooth is fixed in a cavity called the alveolus, in the alveolar bone. The fixation between the root and the bone is made in a ligament consisting mainly of sets of collagen fibers fixed on one side in the bone and the other in the cement, mineralized layer resulting from the differentiation of undifferentiated mesenchymal cells in cementoblasts that produce the organic and mineral matrices that make up the cement. In this cement, the collagen fibers are inserted perpendicularly and even parallel to the cement surface, forming a network between them. An implantation of an artificial tooth, to be functional and accepted, should ideally anatomically and histologically reproduce the protective structures of the natural teeth, ie the cement, the alveolar-dental ligament, the alveolar bone, with all its components: cells differentiated or not, conjunctive fibers and other fibers (elastic, oxitalans, elauin) the fundamental substance, mineralized tissues, vascularization and innervation. Patent application EP-A-734712 (Kanebo Ltd) describes a method of forming an implant by applying a layer of cement particles on its surface. However, the implant thus obtained does not have the collagen fibers inserted perpendicularly into a neoformed cement surface and necessary in the union of the implant in the alveolar cavity. To stimulate the reformation of alveolar-dental ligaments on scraped natural dental roots, Hanes ef al. ("Cell and Fiber Attachment to demineralized cementum from normal root surfaces" Vol 60, No. 4, pages 188-198), study the effect of critical acid treatment of this surface; free cement or dentine fibers by demineralization become joined by "splices" in the collagen fibers of nearby tissue. But there is no "neo-cement", and the fibers remain considerably less dense than a normal periodontal ligament. The fibroblasts, ligament generators, cementoblasts and osteoblasts that are found at the edge of the alveolar bone result from the differentiation of the undifferentiated progenitor mesenchymal cells that usually reside in the connective tissues around the blood vessels. They can be found on the surface of roots of extracted teeth and / or in the alveoli of extracted teeth or in the ligaments of a tooth, or in other connective tissues, buccal or not. The invention results from the disclosure that under certain conditions of biological and mechanical stimulation, the natural physiological environment of the root described herein can be reconstituted from a culture of undifferentiated progenitor mesenchymal cells. The invention proposes to allow the replacement of the lost teeth in a majority of clinical situations, by the inalterable ratific teeth connected to the jaws by the same tissue elements as the natural teeth, that is to say a cement, an alveolar-dental ligament, and an alveolar bone and that allow a normal union of the gum in the neck of the implant. These four elements are the constituents of the periodontium, which can later ensure their normal physiological role, know how to cushion the discomfort of chewing, avoid overloads, adapt the position and mobility of the tooth in the average load it collects. The present invention provides a method of manufacturing a dental implant comprising: the preparation of an implant composed of a root part and a coronal part and constituted of a biocompatible material according to a shape adapted to an extracted tooth; - the immersion of the radicular part of this implant in a culture of undifferentiated progenitor mesenchymal cells, in a culture medium from which the composition allows differentiation in cementoblasts and in fibroblasts, during a sufficient duration in that differentiation and adhesion of cementoblasts on the radicular part and in the formation of a first layer of cement and a sketch of alveolar-dental ligament attached to that cement; - the removal of the implant by all the differentiated tissues fixed on its root part. The choice of implant is guided by different criteria. The first criterion is its morphology. This will depend on the volume of dentine (ivory) of the tooth to be replaced, that is to say the total volume minus the enamel and the cement. The desired shape is obtained, for example, in comparison with the extracted tooth; It will be carved then in the demand, in the exact forms of the tooth to be replaced. The desired shape can also be obtained by radiological, tomodensitometric or equivalent donations. The implant is then carved into a block constituted of a chosen material, by a machine in numerical order, or by another means. A certain number of types of forms can equally satisfy a majority of cases; they will present the roots of lengths, diameters, conicities, round or oval, variable sections. The choice of implant material in the process of the invention is guided on the one hand by the biological and immunological acceptability of said material in the mouth, and on the other hand by its performance as a support for the adhesiveness of the cementoblasts. The material of the implants must be biocompatible, and mechanically strong enough to avoid the risk of fractures, it must also be tarnished on the surface in order to facilitate the adhesion of cells, in Finally, it should be close to the color of the natural tooth. The known materials can be understood in the choice of implant material such as for example titanium, alloys or ceramics for example Zirconium. You may eventually understand using devitalized natural teeth obtained from any source whatsoever. The description of such materials is described in Periodontology 2000 (1998) V7; 7-21. The dental implant used in the method of the invention comprises the root part which is brought into contact with the undifferentiated mesenchymal culture, a coronal part apt to be covered by a crown of resin, composite, metallic alliance or ceramic. The slots are conditioned in the coronal part of the implant to establish the suture threads that hold the implant in its socket when it is put in place in the mouth. In occlusal view of the implant, one slot can for example occupy a diameter and the others cross that diameter to the right angle at equal distance from the center and around. However, these slots can be placed otherwise without disturbing the ergonomics of the system as shown in example 3 herein. The implant put into operation in the method of the invention may finally comprise a stem coaxial with the tooth and be fixed on its coronal part which will facilitate handling and subsequent reimplantation in the mouth. One of the essential characteristics of the method of the invention is the formation by cell culture in vitro, in the presence of the implant, which the form and the material have been selected according to the highest described criteria, of a layer of cells and tissues adherent on the root part of the implant. These cells and tissues exist naturally between the root of the tooth and the alveolar bone; thus, the physiology of reimplantation in the mouth is very similar to similar conditions. It is well known that fibroblasts are the dominant cell type of all connective tissues in human bodies and are in particular the essential cells of periodontium ligament tissues. The differentiated cells of periodontium which are the cementoblasts, the fibroblasts and the osteoblasts come from the differentiation of undifferentiated cells which are the progenitor mesenchymal cells. These cells usually reside in the connective tissues around the blood vessels. They can be taken on the surface of the roots of the extracted teeth if they are not contaminated and / or in the alveoli of the extracted teeth, or in the ligament of a tooth by the capture by a hollow needle or by explants of connective buccal tissues . These progenitor cells exist in other connective tissues of bodies, and can thus be taken at non-oral sites. The undifferentiated cells thus taken are placed in culture under the classical conditions, for example in a Petri dish, in Falcon-type culture dishes, or in roller bottles. The undifferentiated mesenchymal cells taken are placed in culture in a medium, of which the composition allows the growth and its differentiation into fibroblasts. From such media the classical culture media of fibroblast animal cells can be used, such as those described in for example S. Pitaru et al., In J. Périodont Res. (1994), 29: 81 -94, Revie Article, A titre d'exemple, le milieu DMEM (Dulbecco's Modification of Eagle's MEM) (Dulbecco and Freeman, 1959, Morton, 1970) supplemented by a serum of Fetal bovine This medium is supplemented by antibiotics and antifungals as well as elements that favor mineralization. The cells in culture are placed in biological stimulation condition for the addition to the medium of molecules or compositions necessary for the development and in the differentiation of cementoblasts and fibroblasts. It can be made of growth factors, for example we can mention: the PDFG, the IFG, the embryonic enamel organ proteins, the bFGF, and other molecules that have an anabolic effect on the periodontium, for example nifedipine, vitamin C, the unsaponifiables of avocado, corn and / or soy, this list is not limiting. The patent application WO 97/45533 (Rutherford) describes the methods for regenerating different tissues and notably the tissues of the mouth and dental tissues for the ex vivo culture of cells. It describes in particular the culture of cement or alveolar-dental ligament cells, which can be used for dental surgery needs. It describes the use of a structural matrix to allow the differentiation of tissues. Although the cell density reaches 105 cells / ml, the cells are transferred in a culture device that allows the immersion of the root portion of the implant to be treated. The appropriate culture device also forms part of the invention and is described below. The implant is now placed in the culture device until obtaining a layer of adherent cementoblasts in its root part and producing a first layer of cement with the conjunctive fibers inserted in that cement, and a second layer that contains the fibroblasts and collagen in formation. After 15 to 30 days of immersion in the culture medium comprised in the device, the implant is then collected and "implanted" into the mouth in the alveolus under the conditions described in the procedure of example x below. In the method of the invention, the biological stimulation of the cell differentiation of the undifferentiated mesenchymal cells can be completed by a "physiological" mechanical stimulation. It can be performed by a periodic force applied on the implant when immersed in the cell culture. It can also be done by periodic agitation applied to the culture device, the implant being fixed then by all the appropriate means. It tries to apply a relative movement between the implant and the artificial alveolus even in the device containing the culture medium in which the implant is immersed. The agitation may be an alternate movement of periodicity comprising between 1 to 60 seconds without being limited to that interval the method, and of amplitude comprising between 0.005 and 2 mm; the displacement can be horizontal, that is, orthogonal to the implant axis, vertical, that is, length to the axis of the implant or a combination of the two. It can also be a rotating movement. The movement applied to the implant in its culture medium has a double function, conferred by the relative movement between the implant and the artificial alveolus materialized by the porous membrane. The first is to create a functional stimulation of the cells in culture, which increases their proliferation, their differentiation, their synthesis activities (cement and collagen), and the physiological orientation of the structures under formation. The second function of this agitation is to shake the cell culture when it is recommended regardless of which culture of eukaryotic cells; allowing a better aeration of the cells as well as a circulation of medium and its nutrients in the environment of the cells, which favors its development. This agitation can be done throughout the system that allow to regulate the periodicity and amplitude in the forks located later on. It can be a mechanical, electrical, hydraulic, pneumatic, those listed are not limiting. The different embodiments can be understood in this aspect: the movement can be applied only to the implant, by the intermediary of a stem fixed in the coronal part of the implant; it can also be applied to the assembly of the system containing the cell culture in which the root portion of the implant is immersed. Finally, it can be applied to the cell culture, while the implant is fixed on a support by a stem fixed to the coronal part. What is sought in this mechanical agitation is the relative movement of the root portion of the implant and the porous wall that serves as the alveolus even in the device containing the culture medium in which the implant is immersed, under the conditions of periodicity and amplitude recommended below, and that allows to perform the two functions of cell stimulation and agitation of the cells. The present invention also relates to a cell culture device for the preparation of a dental implant. More particularly, when referring to Figure 1, the present invention is directed to a cell culture device for the preparation of a dental implant (30) constituted of a root part (31) and of a coronal part on the which a stem (32) is fixed, by allowing it to be handled and placed in the subsequent mouth: - a culture vessel (10) the shape of which comprises a longitudinal axis, - said culture vessel closed by a lid (1) 1) and containing a porous wall (20) that defines a first space (21) which contains the cell culture medium, and a second space (22) which contains the cells in culture, and in which the root portion of the implant is submerged, said wall having a configuration that allows to leave a space comprising between 0.1 and 5 mm creating an artificial alveolus between the root portion of the implant and the wall and ideally 1 mm. Said device comprises an implant agitation means in said artificial alveolus according to an alternate movement of periodicity comprising between 5 and 50 seconds and of amplitude comprising between 0.005 and 2 mm or according to a rotary movement of periodicity comprising between 1 and 60 seconds . This means of agitation may be mechanical, hydraulic or magnetic so as to confer an alternative or rotary movement to the stem.

Alternatively, the device may comprise a means of agitating the culture vessel, and means for maintaining the dental implant. The present invention is also related to a dental implant that can be obtained by a method such as that described above and that allows the reconstitution on the root surface of the implant of different tissues constituting periodontium, that is cement and the ligament that binds the cement to the alveolar bone. This implant or artificial tooth is made of an inert bio compatible material, according to a form adapted to the extracted tooth. The dental implant according to the invention will comprise a coronal part and a radicular part, which, before the application in the mouth, it will be covered with differentiated cells that allow a more complete formation of cement and ligament in situ. A dental implant according to the invention allows two to three months to ensure the complete reconstitution of a normal periodontium that supports the implant. Finally, the invention is directed to a method for replacing teeth lost or compromised by artificial implants on which they are fixed, by an appropriate cell culture technique, biological tissues thus allowing to obtain a healing in the mouth by cement and ligament, between the osseous alveoli and the implanted roots. The examples of embodiment and the following figures, without being limitative, serve to illustrate the invention and allow the person skilled in the art to perform it directly, or all the functional equivalent that allows to perform the implant on the surface of the root part is upholstered of cementoblasts that form a cement and of collagen fibers and fibroblasts that elaborate the fibers of collagens that reconstitute a sketch of alveolus-dental ligament. Figure 1 depicts a scheme of organotypic culture device around the artificial roots, with biological and physiological (mechanical) stimulation to obtain the cementoge and the ligamentoge and is described in detail in the following example 2: (1) represents the occlusive view (2) is a perspective view. Figure 2b represents the diagrams showing the coronal part of the implant arising from the gum; (A): nearby structures are not yet joined through the mesio-distal groove; (B); the knots are not made. Example 1 - Cell culture procedure that aims to create an in vitro periodontium: 1) Preparation of cells: The intended cell population is that of mesenchymal, undifferentiated progenitor cells that usually reside in connective tissues and in spaces around the body. Blood vesels. Samples can be done by: - scraping the unpolluted surfaces of extracted tooth roots with a sterile scalpel; to obtain the alveolus of extracted teeth, equally uncontaminated, - by periostium or supra-periostos tissue biopsy - by sample of other buccal connective tissues or not. 2) Transport of samples: The tissues are placed in tubes containing Dulbecco's modified culture medium of Eagle's MEM (DMEM) with: - 20% Fetal Bovine Serum (FBS), - Streptomycin (100,000 Mg / ml) ), - fungizone (1%), - buffer system, for a maximum duration of 24 hours and at 4 ° C. 3) Primary culture: - Biopsies are reduced by scalpel in the fragments of close 1 x 1 x 1 mm; - The obtained explants are placed in the 60 mm culture discs containing: - DMEM, - 20% FBS, - 1% penicillin-streptomycin, - 1% fungizone incubated at 37 ° C in moist air at 5 ° C. % of CO2; - after 3 days, the medium is replaced by DMEM + 10% FBS, without antibiotics. 4) Subcultures: When the cell proliferation around the explants is evident, and the cells reach confluence, they are separated with the trypsin at 0. 05% in a serum capped with phosphate for 10 minutes, and distributed in the other culture vessels. - the medium is the same - after 3 or 4 steps, the amount of fibroblasts obtained is enough to seed the root. 5) Adhesion phase: In the same medium added with growth factors, the cells are placed around the artificial root in an artificial alveolus without leaving more than 1/2 m to 1 mm of space. The root and its contents are joined by an adapted stopper. The assembly is placed horizontally to favor the adhesion to the surface of the root, and to turn 1 20 ° all 15 mm. 6) Phase of stimulated culture in the device: After three hours, the root is placed vertically in the culture system with physiological stimulation, and with renewal of the medium to which we add growth factors. 7) Transport conditions: After 15 hours, the device is used to transport the implant ready to be put in place. Depending on the transport times, the system is stored at 37 ° C or remains at 4 ° C. The cement-fed and ligament-fed implant exits the culture device and is immediately placed in the prepared alveolus, then sutured.

Example 2 - Realization of a cell culture device: The figure represents the principle of such a device and the figures in parentheses refer to the different elements of this figure. The dental implant (30) is constituted of a radicular part (31) and a coronal part on which a fixing axis (32) allows its agitation, its handling and its pesita in the posterior mouth. The device comprises: - a culture vessel (10), the shape of which comprises a longitudinal axis; - said culture vessel is closed by a slightly flexible lid (11) and containing a porous wall (20) delimiting a first space (21) distal in comparison to the root part (31) containing the culture medium of the cells, and a second space (22), which contains the cells in culture, and in which the root portion of the implant is submerged. The wall delimiting the two spaces has such a configuration that the second space (22) is shaped and of such dimensions that a space comprises between 0.1 and 5 mm (ideally 1 mm) between the wall (20) and the root part of the implant (31) creates an artificial alveolus. The culture vessel (10) may be circular in section or otherwise. Its section must be sufficient to accept the root of the implant, the second space (22) containing the cells in culture and the first space (21) containing the reserve of the culture medium. The height of the container (10) is greater than at least 10 mm at the total height of the implant, being around 50 mm in height. In the apical part, a space must be reserved for the circulation of the culture medium and that the stem must be accessible to the outside of the container supplied with its cover (11) by a removable fixing ring. The lid (1 1 1) of the container must be adjusted over the latter under the conditions that allow the sterility of the culture medium to be maintained, that which is carried out for example with a lid similar to that of a Petri dish. (1 1) on the container (10) can be, well understood, understood by the person skilled in the art from the moment when the functional characteristics of this device are preserved, the immersion of the root part in a cell culture, said culture forming an artificial alveolus of section comprising between 0.1 and 5 mm around the root portion of the implant 31. The cover may comprise a central part (12) in which the fixation axis (32) of the implant can be adjusted by the intermediary of a fixing ring that allows the container of culture which also serves for transport, in a container and at the moment of putting the implant in its mouth, to be removed in its mouth. thermo-regulated special, protected from all contamination and stabilized in the vertical. The device according to the invention comprises, in another, an implant agitation means according to an alternate movement of periodicity comprising between 5 and 60 seconds and of amplitude comprising between 0.1 and 2 mm or according to an alternate rotational movement of periodicity comprising between 5 and 60 seconds. and 60 seconds.

This agitation has a double function, the usual function of agitation of a cell culture by allowing a correct aeration and a good distribution of culture medium and its nutrients on the suspended or adherent cells; The second function is to create a mechanical stimulation that leads to the cell differentiation sought in cementoblasts and in ligament-generating fibroblasts. This agitation can be conferred on the device in several ways; the movement can be applied to the implant according to a means of mechanical, hydraulic or magnetic agitation applied on the stem (32).

In that case, the lid (1 1) of the container (10) should be provided in the central position of a means for fixing the stem (32) which thus makes it possible to provide an autonomous movement of the implant within the container / lid assembly. For this purpose, the fixing means of the stem in the central position of the lid, or the lid itself (1 1) must have sufficient flexibility for the realization of movement; the movement can be conferred to the container / lid assembly, while the implant is fixed on a support by all appropriate means; still, the lid (11), where the means of fixing the stem on the lid must have the necessary flexibility to carry out the movement. The culture vessel (10) contains two spaces: - a first space (21) containing the culture medium. This can for example be a DMEM-type medium added with fetal bovine serum and in which the different growth factors or molecules necessary for growth and for cell differentiation are added. - a second space (22) containing the cell culture sowed with the pre-culture of mesenchymal cells such as those described above. These two spaces are separated by a porous wall or membrane, or a passage wall that stabilizes a microporous membrane, which has sufficient rigidity to confer a desired and stable shape. This wall has a porosity and a form in which the characteristics are the following: a) the porosity is such that the culture medium containing the nutrients and their growth factors diffuse in the second compartment (22), when the cells remain confined in said compartment. The porosity will comprise between 0.2 and 2 microns. All types of material that allow this porosity and relative rigidity necessary for characteristic b later, it can be used. We will cite, for example, polycarbonate, cellulose acetate (Millipore filter, Millicell), etc. b) The membrane or its assembly system is fixed in the container (10) at a level higher than the level of the culture medium. It can gather the edges of the container (10) in the form of a cone, for example. On the other hand, it creates in the container (10) an artificial alveolus similar to the shape of the root portion of the implant (31) so as to create a space of 0.1 to 5 mm and preferably 1 mm long between the root of the implant and said porous wall. The membrane with its assembly system must be uncoupled to the bottom of the container to remain attached to the lid itself attached to the implant. Thus, when we lift the lid, the first space (21) is fully accessible to modify or load the medium. The assembly of the device comprises the container (10), the lid (11), the wall (20) and the implant (30) is placed in a culture incubator at 37 ° C containing 95% moist air and 5% CO2 Example 3 - Example of structure of an implant: The implant of desired shape is made in a biocompatible material, such as that described in Periodontology 2000 (1998), 17: 7-21. In view of the subsequent implantation, the slots are conditioned in the coronal part of the implant to establish the suture threads that retain the implant in its socket, when it is put in place in the mouth. Alternatively, the slots or passage rings can be conditioned directly on a provisional resin crown fixed on the coronary artery of the implant. The invention is also directed to an implant stabilized in the mouth by provisional crowns especially prepared for the retention of the suture threads by said slots or passage rings. These grooves can measure 1 mm long and 2 mm deep. An example of its arrangement is shown on scheme n ° 2a. This arrangement allows the passage of the suture threads (1) as shows on scheme n ° 2b. A thread is passed in the filling points in the vestibular gingiva (2) and in the lingual gingiva (3) and passes twice through the occlusive side of the implant in the two vestibular-lingual grooves (4). It allows to retain the implant but also to regulate the height of the free edge of the gum compared to the implant. A simple stitch is placed to bring the distant gingival papillae closer to the implant, their two strands are left before the knot in a length of 5 cm. The same operation is performed mesially of the implant when leaving the strands of 20 cm. Then each strand is knotted with each distal strand as it passes through the mesio-distal groove of the implant. The implant is then secured by three sutures. A circular cervical point is often necessary to better gather the gingival margin at the periphery of the implant, and prevent implant stress until it is placed at the level of a maxillary sinus. Example 4 - Implantation in the mouth: The dental implant according to the invention is placed in the mouth after about 1 5 days of culture in the device described below. A method for placing a dental implant according to the invention in the mouth comprises several phases and can be the following: a) Prior oral sanitation and use of antiseptic mouth strands and antibiotics: the oral bacterial load should be reduced to the maximum to avoid contamination of the healing area ..}. b) Preparation of the alveolus: the ideal situation is to have to extract the tooth to be replaced 15 days before. Just then fill the alveolus gently. Partial gingival healing allows adjustment well the implant collar once in place, to obtain a satisfactory hermeticity of the wound that level and scarring by short epithelium. The epithelial cells do not migrate along the root. In the other cases where the alveolus does not preexist more, it should preferably be prepared 15 days beforehand after the elevation of a muco-periosteum shred. The alveolus is prepared by drills of increasing diameters, at slow speed and its irrigation of sterile isotonic serum. The holes are adapted to the standard shapes of the implant types. Certain holes work only on their axis, others allow to "form" the alveolus in an appropriate way by a shear on their side faces. They lead to an alveolus always larger than the implant, leaving a space of at least one millimeter, so that the bone is not in direct contact with the implant. At the level of the breasts, after the elevation of a muco-periosteal shred and perforation of the bone wall, the sinus mucosa is rejected by spacious detachments. This preparation must imperatively be performed about 15 days before implantation, which then allows the sinus mucosa to be put in its place of rejection without the risk of perforating it. c) Models in neutral material and sterilized (sterilizable) are made in the exact form of the implants, complete crowns compressed, standard or individualized to lead to an ideally placed implant, by allowing to control the preparation of the alveolus.

It includes an appnsion shot in the middle of the vestibular face of its coronal part. A second type of model comprises the complete volume of the crown and a root of the length to be prepared but of a reduced diameter. It is used after the first perforation to control the placement and possibly modify it in the extension of the alveolus. The implanted root may not fully maintain bone volume available. If it advances vertically or horizontally from the bone surface, it does not prevent healing and can generate a spontaneous increase in bone volume around the non-hidden root, provided that the surfaces not hidden in the bone remain on the mucous membranes. The same phenomenon occurs in the breast. d) The implant, taken from its culture vessel, supported by its stem and in a fixation ring, is placed intermediately in the alveolus, preferably without contact with the one that comes out, notably an instrument, a compress, the buccal mucosa , the tongue, the saliva ... It is kept in place by the stitches taken on the gum on both sides of the implant, and slides into the grooves prepared in the emerging "coronal" part. The stitches must also ensure the tightness of the gum in the neck of the implant. The points are kept around 15 days. No other application, noticeably stiff in other teeth, is used.

The coronal part of the implant, reduced to that degree because it does not reinforce the provisional crown, nor should it come into contact with the opposing teeth. e) temporary crowns: the standard provisional crowns can be sealed after 15 days on the implants. They are regulated to have an occlusive contact only in a centered relation or maximal intercuspation. Its contour and aesthetics can be regulated by adding or subtracting resin by working with the wheel. The control sessions are indicated to ensure the progressive loading of the implant and to avoid all overloads, for two months. f) The definitive prostheses on the implants can be done about 3 months after putting them in place. Classical techniques can be used. These implants behave exactly like natural teeth. The ligament that joins them absorbs coercion, avoids overloads, reduces impacts, limits the risk of fracture of prosthetic crowns and implants by themselves.

Claims (9)

1. CLAIMS 1. Process for the manufacture of a dental implant comprising: - The preparation of an implant composed of a root part and a coronal part and constituted of an inert biocompatible material according to a shape adapted to an extracted tooth. - Immersion of the root portion of that implant in a culture of undifferentiated mesenchymal cells, with the aid of a device comprising a culture vessel (10), of which the shape comprises a longitudinal axis, said culture vessel being closed by a cover (11) and contains a porous wall (20) delimiting a first space (21) containing the culture medium, and a second space (22) containing the cells in culture, and in which the root part it is submerged, said wall having a configuration that allows to leave a space comprising between 0.1 and 5 mm creating an artificial alveolus between the root portion of the implant and the wall. - the culture of the undifferentiated mesenchymal cells such as those mentioned below and in a culture medium of which the composition allows differentiation in cementoblasts and in fibroblasts, during a sufficient duration for that differentiation, with the adhesion of the cementoblasts on the radicular part, for the formation of a first layer of cement and a sketch of alveolus-dental ligament joined to that cement; The removal of the implant carrying differentiated tissues placed on its radicular part.
2. 2. The method according to claim 1, characterized in that the progenitor mesenchymal cells are deduced in the conjunctive tissues, and are placed in preculture in the Petri dish until obtaining a density of 105 cells per ml, then contacting the root part of the implant in a culture medium and in a device as defined in claim 1.
3. 3. The method according to claim 2, characterized in that the differentiation of the cells into cementoblasts and fibroblasts is stimulated by the addition in the culture medium. of the specific growth factors or all the molecules that stimulate the cellular differentiation of the mesenchymal cells.
4. 4. The method according to claim 1, characterized in that the culture undergoes a physiological stimulation by agitation of the implant in the culture device, said agitation having for effect of stimulating the development of the cells and tissues on the inert material. The method according to claim 4, characterized in that the agitation is reciprocal movement of periodicity comprising between 1 to 60 seconds and of amplitude comprising between 0.005 and 2 mm, or rotating periodicity comprising between 1 and 60 seconds. 6. The cell culture device for the implementation of the method according to any of claims 1 to 5, for the preparation of a dental implant (30) consisting of a root part (31) and a coronal part on which a stem (32) is fixed it allows its manipulation and its placement in the posterior mouth, said device comprises: a culture vessel (10) the shape of which comprises a longitudinal axis, said culture vessel being closed by a cover (11) and containing a porous wall (20) that delimits a first space (21) which contains the cell culture medium, and a second space (22) which contains the cells in culture, and in which the root portion of the implant is submerged, said wall having a configuration that allows to leave a space comprising between 0.1 and 5 mm creating an artificial alveolus between the root portion of the implant and Wall. The device according to claim 6, characterized in that the lid (1 1) comprises in a central position a means for fixing the stem (32) integral with the implant. 8. The device according to claim 6 or 7 comprises another means of agitating the implant in said artificial alveolus according to an alternative movement of periodicity comprising between 5 and 60 seconds and of amplitude comprising between 0.005 and 2 mm or according to a rotary movement of periodicity comprising 1 to 60 seconds. 9. The device according to claim 8, characterized in that the agitation means is mechanical, hydraulic, pneumatic, electric or magnetic and confers an alternative or rotary movement to the stem (32). The device according to claim 8, characterized in that the lid (1 1) is slightly flexible to allow rotary movement. eleven . The device according to claim 8 or claim 9, characterized in that the agitation means is conferred by an alternative or rotary movement of the container (10). The device according to any of claims 6 to 11, characterized in that the porous wall (20) has a porosity comprising between 0.2 and 2 microns. The device according to claim 12, characterized in that the wall (20) is fixed to the container (0) below the level of the culture medium of the cells ..}. 14. A dental implant capable of being obtained by a method according to any of claims 1 to 5, constituted of an inert biocompatible material according to a form adapted to an extracted tooth, of which the surface of the root part (31) is upholstered with cementoblasts that form a cement in the collagen figures, and of fibroblasts that elaborate the collagen fibers that reconstitute an alveolus-dental ligament sketch. The implant according to claim 14, characterized in that the passage slots or rings are placed on its coronal portion to establish the suture threads that retain the implant in its socket when it is put in place in the mouth. 16. The implant according to claim 15 or the passage slots or rings can be adjusted directly on a fixed provisional crown on the coronary stump of the implant.