FR2953124A1 - Endosseous implant for implantation into periodontal bone tissue e.g. gingival tissue of patient, has implantable surfaces including raised texture that is similar to that of surface texture of recipient tissues - Google Patents

Abstract

The implant (100) has implantable surfaces (110, 120) implanted in recipient bone tissues e.g. alveolar bone tissue (210) and cortical bone tissue (220), where the implant is made of sintered ceramic material. The surfaces include a raised texture similar to that of surface texture of the recipient tissues. Fingerprint of a mold of pattern networks is etched on a wall of the surface. Ceramic powder mixed with binder is injected in the mold to obtain a blank. Taper ratio of a net of the surface lies between 0.02 and 0.1. An independent claim is also included for a method for fabrication of an endosseous implant.

Description

FIELD OF THE INVENTION The invention relates to the field of implants, in particular but not exclusively the field of dental implants, intended for humans or animals. 2. Solutions of the Prior Art An implant intended to be adapted in the human or animal body must be in osmosis with the recipient site, for example the bone tissue. In particular, the dental implant must coexist soundly on the one hand with the teeth, on the other hand with the highly corrosive and slightly acidic liquid that is saliva. Furthermore, the implant must be integrated in a fitted manner in the tissues in which it is installed. The dental implant should be best integrated with the gingiva, the cortical bone, which is a hard bone and the alveolar or lamellar bone that is a soft bone, with which it is intended to be in contact. To promote the integration process, it is known to "texture" the external surface of the implant, that is to say to give it a slight relief, by different techniques, such as the oxidation of titanium, the deposition of a layer of HA hydroxyhapatite, laser microspires etching, microspires by machining, sanding treatment of implantable parts, plasma torches, molten metal microballery project, or others. Furthermore, Patent FR 2 900 089 discloses a method of manufacturing an implantable medical device made of polymer, which consists in providing a mold, in texturing by blasting the surface of the mold intended to form the negative replica of the device, and then in manufacturing the device by molding a polymer. 3. OBJECTIVES OF THE INVENTION The object of the invention is therefore in particular to further improve the integration of an implant into the tissues. More specifically, the invention aims to achieve a texturing of the implant that is even more suitable for the tissues in which the implant will be installed. 4. DISCLOSURE OF THE INVENTION The invention achieves this through a method of manufacturing by molding an implant, in particular a dental implant, intended to be implanted in tissues, in particular human or animal tissues. The method comprises the following steps: - acquiring at least one image of the tissues, - performing a computer processing of the image (s), - using the processed image (s) to produce a mold of the implant having a mold impression with at least a surface state of the molding impression corresponding to a surface state of the tissues in which the implant is intended to be implanted, - manufacturing the implant by injecting material into the mold. The molding impression is, according to the invention, textured to reproduce the surface state of the tissues. The implant will therefore have a surface state reproducing the surface state of the tissues. Thus, thanks to the invention, there is an implant whose surface is textured in a manner adapted to the tissues in which it will be implanted. The image of the tissues can be a three-dimensional (3D) image. Alternatively, the tissue image may be a two-dimensional (2D) image. The acquired image can be in the form of a cloud of points. Computer image processing may consist of forming, from one or more of the tissue images, a continuous surface image using image processing software.

It should be noted that the images of the tissues that are acquired are not necessarily those of the tissues in which the implant manufactured will be integrated, but tissues of the type of those in which the implant will be integrated. For example, the tissues may be those of another person or of another animal, or even of another part of the body but of similar texture for example.

The method may include the further step of removing the implant after the injection step in the mold, and cooking and / or sintering. According to one embodiment, the mold can be manufactured with several different surface states. For example, for a dental implant, the mold may be fabricated with a surface condition of a cortical bone and / or a surface condition of an alveolar bone and / or a surface condition of a lamellar bone and a condition surface of a gingival tissue. In this case, the implant will be best integrated with the gingiva, cortical bone and lamellar or alveolar bone. In particular, thanks to this aspect of the invention, the bones will colonize so can integrate the implant quickly, and the attachment of the implant to the gum may be stronger. The image or images of the tissues can be acquired using a device selected from the group consisting of: a three-dimensional digital scanner with or without contact, a scanning microscope, a triangulation scanner, a scanner, a scanner medical equipment, a conoscopic holography, a modulated light scanner, a three-dimensional laser scanner, a three-dimensional panoramic scanner, a probe, an ultrasound scanner, a sonar, a radar, a scanner without passive contact, a scanner with a silhouette, a stereoscopic scanner, a hand-held scanner and a vector-based camera, and any other 2-dimensional or 3-dimensional imaging system. The image processing software may be computer-aided design (CAD) software configured to, from point clouds forming the acquired image, produce at least one three-dimensional continuous surface image by three-dimensional polygonal modeling. dimensions. Three-dimensional polygonal modeling can determine and connect adjacent points to create a continuous surface. A plurality of continuous surface images can be assembled using computer-aided design (CAD) software to reproduce a three-dimensional surface plane forming the plane of the mold. The surface plan reproduces the relief of the tissues that one seeks to obtain. The surface plane can be scaled to the desired plane of the molding footprint. The enlargement of the scale can also help to refine the details of the relief or texture.

The mold can be manufactured by material subtraction machining using at least one computer-controlled rotary tool using computer-aided design and manufacturing (CAD / CAM) software, so as to reproduce the same at the same time. less a three-dimensional image with a continuous surface, in particular the three-dimensional surface plane. The method may comprise the step preceding the manufacture of the mold, consisting in treating the three-dimensional surface plan so as to define the path and the choice of the rotary tool or tools that will be used to control a machine tool supporting the rotary tool. The rotary tool used can be provided with several axes able to reproduce any type of volume with precision. The mold may be metallic, for example, in particular stainless steel.

The manufacturing technique of the mold can be chosen from the group consisting of: machining, photoengraving, etching, chemical etching, sandblasting, spark erosion (also called EDM, Electrical Discharge Machining) and any other technique for reproducing a three-dimensional surface in at least a portion of the mold or combination thereof.

The implant manufacturing step may be carried out by a technique chosen from the group consisting of: ceramic injection molding (CIM), metal injection molding (MIM) ), plastic injection molding (PIM, plastic injection molding), in particular depending on the material of the implant.

The implant may be made of zirconia or other material undergoing shrinkage during firing, the method may then comprise the step of, after acquiring one or more tissue images, enlarging said image so as to take into account the shrinkage. when cooking zirconia or other material. Indeed, the zirconia, during sintering or cooking, can see a shrinkage of between 20% and 50%. The method may include the step after injection and optionally baking and / or sintering, of sterilization of the implant, so as to allow it to be ready for implantation into the tissues. The invention also relates to an implant obtained by the implementation of the method described above. The implant may comprise a material selected from the group consisting of: ceramics such as zirconia, metals such as austenic stainless steels, ferritic stainless steels, martensitic stainless steels, carbon steels, coefficient metal materials Controlled dilation, particularly Invar® and Kovar®, soft magnetic materials, especially those containing between 50% and 80% nickel, polymers such as polyacetal copolymer, polyethylene, polysulfone, polyetheretherketone polymer ( PEEK), and any other implantable material injectable in a mold or reproducible by molding. The implant may be a dental implant. The implant may for example be chosen from the group consisting of: sealed prostheses such as false abutments, abutments, crowns or bridges, transitional or temporary parts waiting for definitive parts. Sealed prostheses, which are abutments, are prosthetic elements transferred to the implant intended to receive the crowns or bridges which will be sealed with cement or composite some of which is still in contact with the gingiva. The abutment is directly attached to the implant located under the gum. The abutments are screw-retained portions and / or screwed directly on the implants always in contact with the gingiva for generating a touch-sensitive attachment of the gingiva which makes it possible to screw one or more prosthetic elements such as bridges. The pillar is in contact with the gum.

Crowns or bridges can also be transferred directly to implants. They can be custom made by CAD / CAM. We can use an injected part called "carrot" which has a surface condition and a connection compatible with the dimensions of the implant. Temporary or transitional parts waiting for the final parts can also be manufactured by injection with the manufacturing method above. These parts may be injected in PEEK (polyetheretherketone polymer) by the PIM method. 5. List of Figures Other features and advantages of the invention will appear more clearly on reading the following description of an embodiment of the invention, given by way of illustrative and non-limiting example and the accompanying drawing. in which: - Figure 1 shows in block diagram the process according to the invention; - Figure 2 shows, in section, schematically and partially, the mold and the implant manufactured using the method according to the invention; and FIG. 3 schematically illustrates, in section, an implant according to the invention after its integration into the tissues. 6. Detailed Description of an Embodiment of the Invention FIG. 1 shows the method according to the invention, in block diagram. It is a method of manufacturing by molding an implant, in particular a dental implant, intended to be implanted in tissues.

The method comprises a step of acquiring at least one image of the tissues, in particular a 2D or 3D image. To acquire the image, it is possible for example to take one or more tissue samples depending on the physiology of the recipient site. In the case of a dental implat, it may for example take a sample of a portion of a cortical bone, alveolar and / or lamellar to recreate these textures on the part or portions of the implant that will be in contact with the different categories of bone and a sample of gingival tissue to recreate the texture of the gingiva in the upper parts of the dental implant intended to be in contact with the gingiva.

The acquired image can be in the form of a cloud of points. The image can be acquired using a device selected from the following: a 3D digital scanner with or without contact, a scanning microscope, a triangulation scanner, a tomograph, a medical scanner, a conoscopic holography, a modulated light scanner, 3D laser scanner, 3D panoramic scanner, probe, ultrasound scanner, sonar, radar, passive contactless scanner, silhouette scanner, stereoscopic scanner, manual scanner and vector camera , and any other shooting system in 2 or 3 dimensions. In a step 11, the method consists in performing a computer processing of the image or images acquired in step 10. Such computer image processing may consist in forming, from one or more of the tissue images, a continuous surface image. Indeed, as indicated above, the image or the images acquired can be in the form of a scatter plot and the image processing software can be a CAD software (Computer Aided Design) configured for, at From the point clouds forming the acquired image, make at least one continuous surface 3D image by 3D polygonal modeling. 3D polygon modeling can determine and connect adjacent points to create a continuous surface. In a step 12 a CAD software can be implemented to assemble several continuous surface images from step 11 so as to reproduce a 3D surface plane forming the plane of the mold. Indeed, the surface plan reproduces the relief of the tissues that one seeks to obtain. The surface plane can be scaled to the desired plane of the molding footprint. The enlargement can also help to refine the details of the texture. In a step 13, the mold is manufactured for example by machining by subtraction of material using at least one computer-controlled rotary tool using CAD / CAM software (Computer Aided Design and Manufacturing). in order to reproduce the continuous surface 3D image or the 3D surface plane obtained in step 12. To do this, the 3D surface plane can be processed so as to define the path and the choice of the rotary tool (s) to be used for controlling a machine tool supporting the rotary tool The rotary tool used can be provided with several axes capable of reproducing any type of volume with precision. The manufacturing technique of the mold may be chosen from the following: machining, photoengraving, etching, chemical etching, sandblasting, EDM (also called EDM, electrical discharge machining) and any other technique for reproducing a 3D surface in at least a portion of the mold or combination thereof. A step 14 is then used to manufacture the implant by injecting material into the mold. Depending on the material used for the implant, one of the following techniques may be used: CIM (Ceramic Injection Molding), MIM (Metal Injection Molding) or PIM (Plastic Injection Molding). Finally, in a step 15, the implant is ejected or removed from the mold and baked and / or sintered to give it the appearance and final shape before implantation into the tissues.

Shown in Figure 2 in schematic and partial section the mold 20 and a dental implant 21 made according to the method according to the invention. The mold 20 is in this example made of a metal such as stainless steel. The molding impression has been made by machining using a rotary tool so as to form a mold cavity 22 having a plurality of surface states corresponding to the different tissues in which the implant is intended to be integrated. In particular, the molding impression comprises a first surface state 23 whose surface texture corresponds to that of the tissue in which the implant will be integrated, namely, as illustrated and visible in FIG. 3, the part in contact with the alveolar and / or lamellar bone OA. A second surface condition 24 is provided on the molding cavity 22 of the mold 20 so as to facilitate the implantation of the dental implant in contact, on this portion with the cortical bone OC. In this illustrated example, a third surface condition 25, allows the molded implant to have a texture at this location corresponding to that of the gingiva G visible in Figure 3 with which it is in contact. The part of the implant 21 in contact with the surface state 23 of the mold cavity 22 is the lower part of the implant 26. The part of the implant 21 in contact with the surface state 24 of the mold cavity 22 is the intermediate portion 27. The part of the implant in contact with the surface condition 25 is the upper part of the implant 28.

An upper portion 29 of the implant allows the junction of the implant with a abutment to the abutment 30 visible in Figure 3 and for supporting a ring 3. In the example shown, the implant is therefore dental and can be made of zirconia, in particular of yttria zirconia.

In this case, the method according to the invention may comprise the step of, after acquiring one or more tissue images, enlarging the image so as to take into account the shrinkage during the baking of the zirconia. Indeed, the zirconia, during sintering or cooking, can see a shrinkage of between 20% and 50%. To use zirconia which is a ceramic to make an implant, one can proceed as follows, for example. A specific implantable zirconia powder is prepared for injection with a binder (feed stock). Zirconia is a zirconium oxide of chemical symbol ZrO2. The yttria zirconia used is an extremely fine powder of zirconium oxide containing a controlled amount of yttrium oxide. Yttrium is a metal of anatomical number 39 of the rare earth group. A polymer, a mixed wax system, a mixture of polyolefin wax or polyoxymethylene (POM) are added to the yttria zirconia. A mixer or extruder can be used to mix the components. The physical characteristics of the yttria zirconia are its chemical inertness, its lack of toxicity, bimetallism (there is no electrochemical effect), its absence of erosion, its absence of NMR scanner flash (nuclear magnetic resonance ), its wear resistance with a very low coefficient of erosion. Once the zirconia ytria paste, it is placed in the injection press and the mold is installed in the press. The press then injects the zirconia paste into the mold using a hot extrusion screw rotating so as to push the zirconia towards the mold. The pressure and the pressing time are regulated. After a few seconds, the mold opens and the pieces are ejected. Then the mold closes and another production cycle begins. After a verification step of implants made after ejection, they are placed on a specific support. The injection binder is then removed by carrying out a debinding operation. For this purpose, thermal or chemical degradation can be used. The implant is then checked for any defects. The implant and its support undergo a baking step for sintering or baking in order to increase the density of the material and to eliminate porosities. It is at this stage that the removal of 20 to 50% of the zirconia takes place. A finish and / or a last control makes it possible to complete the process.

The invention is of course not limited to the examples which have just been described. The abutment 30 or and / or the crown may be made using molds resulting from the implementation of the method according to the invention for texturing their surface in contact with parts of the body and tissues.

The parts in contact with the tongue and saliva for example, in particular the rings 31, can be made so as to have a smoothest possible surface made by processing the mold at the desired locations. The implant can be a dental implant or the like. It can be intended for humans or animals.

In the illustrated example, a dental implant with zirconia has been made, but any other material may be used as long as it is injectable in a mold reproducible by molding and obviously compatible with implantation in a human or animal body. Metal injection molding (MIM) techniques can for example be used for austenic stainless steels, ferritic stainless steels, martensitic stainless steels, carbon steels, metal materials with a controlled coefficient of expansion, such as Invar® or Kovar®, or even soft magnetic materials, comprising between 50% and 80% nickel, for example.

Austenic stainless steels, in particular 316L steel, offer very good corrosion resistance (greater than 304) and mechanical properties are equivalent to forged 304. If superior mechanical properties with equivalent corrosion resistance are required, 17-4 ph can be used. These steels are non-magnetic.

Ferritic stainless steels, such as 430L, have magnetic properties and good corrosion resistance. Martensitic stainless steels can be selected from 420 which can be heat treated at 52HRC or 440L which can be heat treated at 55HRC. The carbon steels can be selected from AISI 52100 which can be heat treated at 58HRC or M2 tool steel which can be heat treated at 62HRC. Invar® or Kovar® have low or uniform thermal expansion coefficients, are difficult to machine. Soft magnetic materials comprising 50% or 80% nickel have excellent magnetic properties but are difficult to machine. Plastic materials can also be used and the technique used will then be plastic injection molding (PIM). This molding technique can also be used for composite materials. The composite materials that can be used in the field of polymers and composites can be chosen from the following. The non-implantable polyacetal copolymer (POM C) can be used for the manufacture of instrument elements and test prostheses for the production of transient prostheses. Polyethylene (PE) is implantable and can be used for the fabrication of prosthetic elements (eg hip cup, tibial spacer in knee prosthesis, for example). Polysulfone (PSU) is used for surgical instruments, medical cabarets. PEEK (polyetheretherketone) polymer offers a unique combination of properties including mechanical strength and high temperature performance, can be in unloaded, depth-filtered, glass filled, carbon loaded and wear resistant grades.

The standard PEEK polymer has the following technical characteristics: it has excellent strength, rigidity, dimensional stability in high temperature environments and hostile environments. It is easy to process and lightweight compared to steel, aluminum and titanium. It has a low coefficient of friction and wear resistance without lubrication. It is resistant to chemicals and insoluble in ordinary solvents including acids, salts and oil. It has a low bubbling rate, low particle production and inherent purity for reduced contamination and provides electrical isolation. 7. Detailed description of the possible techniques used for the implementation of the invention. For image acquisition, it is possible to use a 3D scanner, a contact scanner, a contactless scanner (without active contact or by flight time or by triangulation), a conoscopic holography a manual scanner, a light scanner structured, a modulated light scanner, a passive non-contact scanner, a stereoscopic scanner, a silhouette scanner, a scanner requiring user assistance, lasergrammetry, tomography, atomic force microscopy, photogrammetry. Images acquired undergo computer processing. One usable technique is 3D modeling. The techniques for reproducing the desired surface state in the injection mold may be as follows: etching, electron beam lithography, chemical etching, photolithography, physical etching, plasma etching, reactive ion etching, machining, sanding, spark erosion. The materials used to make the implant may for example be chosen from the following: - Zirconia - 316L stainless steel - Grade 5 titanium - Stainless steels - Plastics for the medical surgical field such as POM C or PE (polyethylene) or PSU (polysulfone) or PEEK polymer The injection molding technique used will depend on the material of the implant, in particular MIM, CIM or PIM. MIM: The technique of metal injection molding (MIM) is a process used for the production of small metal parts. The process employs extremely fine metal powder to which a binder is mixed and injected into a conventional modified injection mold. The base material is a mixture of thermoplastic binder that will allow the shaping of the piece which is associated with a metal powder that will constitute the final piece. The percentages retained are 60% of powder and 40% of binder.

The mixture is injected into a mold in order to obtain the shape of the part. Once this is done, the binder is removed with temperatures of about 220 ° C. Then comes sintering which will increase the density of the material and eliminate the porosities, (the shrinkage is estimated to be 10 to 20%). The finish completes the process. CIM: The ceramic injection molding technique allows the manufacture of ceramic parts of small sizes and complex shapes, while limiting the machining operations. The elimination of the raw injection binder (or debinding) is a delicate step of the process. A molding, without injection defect, of simple ceramic parts of various thicknesses, and of various compositions (alumina, silicon nitride, zirconia), of the elimination of the binder by thermal or chemical degradation Then comes the sintering which will increase the density material and will remove porosities, (shrinkage is estimated to be 20-50%). The finish completes the process. The PIM Also called plastic injection, it is a method of implementation of thermoplastics.

Most thermoplastic parts are made with plastic injection molding machines.

Throughout the description, the terms "comprising one" or "comprising one" should be understood as being synonymous respectively with the terms "comprising at least one" and "comprising at least one", unless the opposite is specified. The indicated ranges are understood to include the terminals, unless otherwise specified.

Claims (16)

REVENDICATIONS1. Method for manufacturing by molding an implant, in particular a dental implant, intended to be implanted in tissues, characterized in that it comprises the following steps: - acquiring at least one image of said tissues, - performing a computer processing of said one or more images, - using said processed image or images to produce a mold of the implant having a mold impression with at least one surface state of the molding impression corresponding to a surface state of the tissues in which the implant is intended to be implanted, - manufacture the implant by injecting material into the mold. The method of claim 1, wherein the tissue image is a three-dimensional image. The method according to one of the preceding claims, wherein the computer image processing comprises forming a continuous surface image from one or more of said tissue images, using an image processing software. images. The method of any of the preceding claims, including the step of removing the implant after the injection step in the mold, and cooking and / or sintering. A method according to any one of the preceding claims, wherein the mold is made with a plurality of different surface states, including a surface condition of a cortical bone and / or a surface condition of a cellular bone and / or a surface condition of a lamellar bone and a surface condition of a gingival tissue. The method according to any one of the preceding claims, wherein the one or more tissue images are acquired using a device selected from the group consisting of: a three-dimensional digital scanner with or without contact, a microscope scanning, triangulation scanner, tomograph, medical scanner, conoscopic holography, modulated light scanner, three-dimensional laser scanner, 3D panoramic scanner, probe, ultrasound, sonar, radar, scanner without passive contact, a silhouette scanner, a stereoscopic scanner, a manual scanner and a vector camera, and any other two or three dimensional imaging system. 7. The method according to claim 3 and optionally any one of the preceding claims, wherein the image processing software is a computer-aided design software configured for, from point clouds forming the acquired image, to realize at least one continuous surface three-dimensional image by three-dimensional polygonal modeling. 8. The method of claim 3 or 7 and optionally any one of the preceding claims, in which several images with a continuous surface are assembled using a computer-assisted design software so as to reproduce a three-dimensional surface plane. dimensions forming the plane of the mold. A method as claimed in any one of the preceding claims, wherein the mold is fabricated by material subtraction machining using at least one computer-controlled rotary tool using design and fabrication software. computer-assisted, so as to reproduce said at least one three-dimensional image with a continuous surface, in particular the three-dimensional surface plane. 10. Process according to any one of the preceding claims, in which the technique for manufacturing the mold is chosen from the group consisting of: machining, photoengraving, etching, chemical etching, sandblasting, electroerosion and any another technique for reproducing a three-dimensional surface in at least a portion of the mold or combination thereof. 11. A method according to any preceding claim, wherein the step of manufacturing the implant is carried out by a technique selected from the group consisting of: ceramic injection molding, metal injection molding , plastic injection molding. 12. A method according to any one of the preceding claims, wherein the implant is made of zirconia or other material undergoing baking shrinkage, the method comprising the step of, after acquiring one or more images of the fabrics, to be enlarged. said image so as to take into account the firing shrinkage of the zirconia or other material. 13. Implant obtained by carrying out the method according to any one of claims 1 to 12. 14. Implant according to the preceding claim, wherein the implant comprises a material selected from the group consisting of: ceramics such as zirconia, metals such as austenic stainless steels, ferritic stainless steels, martensitic stainless steels, carbon steels, metallic materials with controlled coefficient of expansion, in particular Invar® and Kovar®, soft magnetic materials, especially those containing between 50% and 80% nickel, polymers such as polyacetal copolymer, polyethylene, polysulfone, polyetheretheretherketone polymer, and any other implantable material injectable in a mold or reproducible by molding. The implant according to any one of claims 13 to 14, wherein the implant is a dental implant. 16. Implant according to the preceding claim, wherein the implant is selected from the group consisting of: sealed prostheses such as false stumps, abutments, crowns or bridges, transitional or temporary parts waiting for definitive parts.