OSSEOINTEGRABLE IMPLANTS AND SCREWS COMPRISING STRUCTURALLY POROUS SURFACE, PROCESS FOR PREPARING THE IMPLANTS AND SCREWS AND USES THEREOF

Abstract

The present invention relates to implantable medical devices (dental and orthopedic) (osseointegrable implants) textured by the additive manufacturing process. Such implants are prepared in such a way as to comprise a larger surface area of contact between implant/adjacent tissues, porous microstructure with complex geometry with controlled and diversified pore size, which confers several technical advantages. In addition, the present invention relates to the process of preparing said implants and/or screws with an optimized structure for accelerating osseointegration. Finally, the present invention refers to the use of said implants as carriers of drugs or cells in order to treat the site, promote its healing, tissue regeneration or promote cell growth.

Claims

1.-13. (canceled)

14. A method for preparation of dental or orthopedic implant or screw (implantable medical device), said implant having a trabecular region, characterized by comprising the following steps: a) preliminary preparation of a dental or orthopedic implant or screw (endo-osseous implantology) or selection of an available implant or screw; b) analysis of the intended location of the product, for example, morphological analysis by imaging tests such as computed tomography of the indicated location; c) obtaining patient data to verify integration needs; d) analysis of implant loading or screw in order to determine an optimized implant topology wherein the textured surface is limited to the trabecular region and is determined geometrically by the shape of the implant/screw; e) computer model of a texture comprising porous surface design comprising pore size, wall thickness and other characteristics of the implant or screw surface wherein the thread pitch of said model is constant for any given data; and f) reproduction of the texture in the implant in a controlled manner using the additive manufacturing technique; wherein said process comprises at least one of the following additional steps: g) heat treatment when applicable, for metallic and bioceramics only; h) sintering when applicable, for bioceramics only; i) machining when applicable, for metal only; j) cleaning; k) anodizing when applicable, for metallic ones only; I) laser marking when applicable, according to the total dimension of the component; m) quality control; n) final cleaning; o) packaging; P) labeling; and q) sterilization.

15. The method according to claim 14, characterized by the implant loading analysis of step d) is carried out by means of biomechanical analysis or numerical simulation by the finite element method.

16. The method according to claim 15, characterized by the pore diameter is equal to or greater than 0.3 mm.

17. The method according to claim 14, characterized by the material used in step f) is selected from the group consisting of metals, polymers or ceramics including resorbable or non-resorbable biocompatible polymers, titanium and its alloys, resorbable metal alloys, other metal alloys such as NiTi (nitnol) and bioceramics.

18. The method according to claim 17, characterized by step f) is done by using an additive manufacturing technique of three-dimensional printing.

19. A dental or orthopedic implant, characterized by being obtainable through the method as defined in claim 18.

20. A dental or orthopedic screw, characterized by being obtainable through the method as defined claim 18.

21. Use of a dental or orthopedic implant as defined in claim 19 characterized by being a drug carrier to promote local treatment, local cell growth and/or tissue regeneration.

22. Use according to claim 21, characterized by the drugs being selected from the group consisting of peptides, growth factor proteins, antimicrobial and phototherapeutic drugs, stem cells and biostimulators.

23. Use of the dental or orthopedic screw as defined in claim 20, characterized by being a drug carrier to promote local treatment, local cell growth and/or tissue regeneration.

24. Use, according to claim 23, characterized by the drugs being selected from the group consisting of peptides, growth factor proteins, antimicrobial and phototherapeutic drugs, stem cells and biostimulators.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention will be described on the basis of the drawings attached hereafter, which illustrate:

[0041] FIG. 1 illustrates detail of a dental implant, of the state of the art, prepared by a traditional process;

[0042] FIG. 2 illustrates a detail of a dental implant, of the state of the art, prepared by a traditional process;

[0043] FIG. 3 shows a detail of a dental screw, from the state of the art, prepared by a traditional process;

[0044] FIG. 4 shows a detail of a dental screw, from the state of the art, prepared by a traditional process;

[0045] FIG. 5 illustrates detail of the surface of a dental implant manufactured using 3D printing technology, but without the microstructure of complex geometry;

[0046] FIG. 6 illustrates the detail of the surface morphology of a dental implant manufactured via 3D printing technology;

[0047] FIG. 7 illustrates a side view of a dental screw, object of the present invention, where it is possible to observe the architecture of the complex geometry and with controlled pore size in its structure;

[0048] FIG. 8 illustrates a top view of a dental screw, the object of the present invention;

[0049] FIG. 9 illustrates two perspective views of a dental screw, the object of the present invention;

[0050] FIG. 10 illustrates longitudinal section of a dental screw, object of the present invention, where it is possible to observe the architecture of the complex geometry and with controlled pore size in its structure;

[0051] FIG. 11 illustrates side view and expanded details of a dental implant, object of the present invention, where it is possible to observe the architecture of the complex geometry and with controlled pore size in its structure;

[0052] FIG. 12 illustrates longitudinal section of a dental implant, object of the present invention;

[0053] FIG. 13 illustrates a top view of a dental implant, object of the present invention;

[0054] FIG. 14 illustrates perspective views of a dental implant, the object of the present invention;

[0055] FIG. 15 is a photo of the dental screw, object of the present invention;

[0056] FIG. 16 is a photo of colored versions of the dental screw, object of the present invention;

[0057] FIG. 17 is a photo of the dental implant, the object of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0058] The present invention relates to osseointegrated implants and screws prepared from additive manufacturing (commonly known with 3D printing). With this process, it is possible to influence the texture (microstructure) of the surface and the mechanical structure of the implantable medical device. It is noteworthy that other known manufacturing processes are not capable of this feat.

[0059] Through this process, it is possible to control the roughness morphology and even the complete structure of the implant (for example, ceasing to be massive and becoming porous in regions of less mechanical stress) as can be seen from FIGS. 5 and 6.

[0060] The impossibility of influencing the texture limits the use of the processes traditionally used in the preparation of texture with geometry and controlled pores of dental and medical implants. Conventional processes of obtaining and endo-bone screws and implants do not allow the control of the texture of dental and medical implants. With the present invention, the texture achieved allows, still to serve as a reserve for biomodulators, materials that would be stored in specific positions and that favor the growth of specific cells, or even the inhibition of others (for example, bactericidal/bacteriostatic in the upper part—close to the gingiva—and osteoblast stimulators in the region of the apex—tip—of the implant. This type of selective “carrying” for biomodulators, or even greater geometric affinity, cannot be achieved with the conventional process and can be easily verified with the cell growth analysis process.

[0061] Thus, the implant, object of the present invention, comprises a much rougher surface when compared to implants prepared by traditional processes.

[0062] Further, the process of the present invention allows to result in an implant with a much rougher surface as well as to program textures on the surface with geometric freedom unattainable in any other process. Thus, there are at least three advantages with the use of the process of the present invention when compared to the state of the art: [0063] A rougher surface is more interesting to osseointegration and cannot be obtained by conventional manufacturing processes; [0064] Process allows, in addition to the naturally rougher surface, to generate superficial microstructure that provide even better bone integration of the implant and screw (implantable medical devices); [0065] Textures can be used to carry (drug release)—peptides, proteins growth factors, antimicrobial and phototherapeutic drugs and stem cells as well as different amounts of biostimulators or antimicrobials (chemical agents), selective transport, which encourage growth or fighting certain cells.

[0066] It is important to note that the human being has very different cellular structures in human bone. While the outermost layer (cortical) of the surface is dense and of greater hardness, the innermost region of the bone (medullary) has a more porous structure.

[0067] With the control of the texture of the implant (be it dental or orthopedic), it is possible to design textures that meet the specific need of the place where the implant will be used.

[0068] Thus, in addition to producing line products with these characteristics, with texture control, customized products can be manufactured for the patient, or by known region of the body. In a preferred embodiment, for the mandible, some standard solutions are prepared with, for example, 60% of the implant with a first texture and 40% with a second texture.

[0069] Further, the possibility of storing different amounts of molecules (chemical agents) allows to encourage greater growth of certain cell types in different regions of the implant, or even the fight against microorganisms in situations of infection.

[0070] FIG. 9 illustrates an example of a dental screw in which the reduction in mass of said screw is 26% in relation to the screw of similar geometry currently available on the market, but without the external part with modified microstructure.

[0071] FIGS. 7 and 10 illustrate an example of orthopedic screw composition with structure modification.

[0072] FIG. 7 illustrates a view of the screw with porous microarchitecture and complex geometry.

[0073] FIG. 10 illustrates a longitudinal section of the screw with emphasis on: [0074] first and fourth regions 1 and 4, where the density is the maximum possible because it is a region with high loads when using and inserting the screw in bone tissues; [0075] a second region 2 where there is a reduction in density in a planned way, aiming at increasing the available area to favor the growth of bone tissue within this controlled porous microarchitecture; [0076] a third region 3 that has a structural function and undergoes frictional loads on insertion into bone tissue, being necessarily massive.

[0077] FIGS. 11 and 12 show an example of dental implant composition with structure modification.

[0078] FIG. 11 illustrates a view of the implant with porous microarchitecture and complex geometry.

[0079] FIG. 12 illustrates a longitudinal section of the implant with emphasis on: [0080] a first 1′ region, where the density is the maximum possible because it is a region with high loads when using the implant for its purpose (dental rehabilitation); [0081] a second region 2′ that has a structural function and suffers frictional loads, being necessarily massive; [0082] a third 3′ region where there is a reduction in density in a planned way, aiming at increasing the available area to favor the growth of bone tissue within this controlled porous microarchitecture.

[0083] It should be noted that the mass reduction data between 26 and 30% presented above are exemplary. Structural optimizations can lead to very different reductions, always considering the optimization that the product is aimed for in order to fulfill its function.

[0084] FIG. 14 illustrates an example of a solution, where the innermost part of the screw is kept solid while another (outermost) part of the implant has had its structure changed to a porous micro-architecture with complex geometry by adopting a gyroid structure. In the region in question, the density of the implant became 36% of the solid part in the trabeculated region. The total reduction in the mass of the implant with the adoption of this porous section is 30% in relation to the same massive model.

[0085] The process of the present invention comprises the following steps: [0086] Model the texture in a specific way on a computer; and [0087] Reproduce the texture on an implant or prosthesis in a controlled manner using the additive manufacturing technique.

[0088] In other words, the process of preparing an osseointegrated dental or orthopedic implant or screw (implantable medical device) of the present invention comprises the following steps:

a) preliminary preparation of a dental or orthopedic implant or screw (endo-osseous implantology) or selection of implant or screw available;
b) analysis of the intended location of the product, for example, morphological analysis by imaging tests such as computed tomography of the indicated location;
c) obtaining patient data to verify integration needs;
d) analysis of the loading of the implant or screw in order to determine an optimized topology of the implant;
e) computer model of a texture comprising drawing of the porous surface comprising geometry and pore size, wall thicknesses and other characteristics of the implant or screw surface; and
f) reproduction of the texture in the implant in a controlled manner using the additive manufacturing technique.

[0089] One embodiment of the production process of the present invention comprises the following steps:

a) Design involves topological optimization aiming at the transmission of mechanical efforts. Here, the characteristics and mechanical properties of the different raw materials are considered (metals, polymers or ceramics including titanium and its alloys, nitinol alloys—NiTi, resorbable metal alloys based on magnesium, manganese and zinc, bioceramics such as: hydroxyapatite, beta-tricalcium phosphate and zirconia);
b) Subsequently, the trabecular/porous region is projected, limited geometrically by the shape of the screw. The porosity/geometry of the porous region is also projected considering the possibility of coating with carriers of chemical agents and/or biomolecules;
c) Once the complete design of the component is established, digital processing is then carried out to prepare the additive manufacturing process;
d) The physical component is obtained by the additive manufacturing process. The process is chosen according to the raw material adopted;
e) After the additive manufacturing process, there will be, according to the raw material, the subsequent process of heat treatment, sintering, machining, cleaning, anodizing, laser marking, quality control, final cleaning, packaging, labeling and sterilization.

[0090] With the use of the chemical and mechanical processes currently used, there is no possibility of obtaining surfaces with this structural architecture like those obtained by the process of the present invention. This advantage is a great differential because: [0091] Different people have different bone structures; [0092] Different body regions have very different bone structures; [0093] The process of the present invention allows more precise control of the geometry and size of the interconnected pores to apply as texture, and direct comparison to a model, for example, CAD model (design and computer) between what was designed and what was obtained; [0094] Stimulators or cell growth inhibitors can be added to the implant in specific positions and in controlled quantities, called selective carriage; [0095] It becomes possible to model the texture in a specific way on a computer and reproduce it in a controlled way using the process of the present invention. The more determined control of the geometry stands out than with any other process.

[0096] Therefore, the process of the present invention and the products generated by said process (screws and implants with designed structure) offer additional differentials: [0097] Regarding the function of the screws: better/faster meeting the patient's need regarding the reestablishment/rehabilitation of the function and/or the aesthetic action; [0098] As for the design made specifically for the projected load: Topology aimed at minimizing the material of the implant/screw under the condition of support of the mechanical efforts applied to the component (topological optimization) with 25 to 40% reduction of raw material; [0099] As for the control for carrying cells/drugs: topology aiming at structuring the position and number of carriers of molecules along each component according to the application and purpose; [0100] Regarding productivity and financial viability: technical/financial viability of the production of items with great geometric complexity and optimized according to the application; [0101] Regarding the possibility of different raw materials for the pieces: design method allows diversity of materials in the product with very similar (but not the same) production principles, differently from traditional production processes that have clear limitations regarding the diversity of raw materials.

[0102] It is noteworthy that the design and production process observe geometric characteristics that cannot be obtained by means of subtractive manufacturing, but only by the additive manufacturing process. This characteristic is essential and genuine to the present invention.

[0103] The understanding of the mechanical load on the components is a limiting factor of the implant/screw area with a trabecular region. It is understood here that the transmission of forces on the implant depends on whether it is massive. Thus, if the loads are very high and the screw has a limited diameter, it is possible that the region with trabeculated structure is limited.

[0104] The present invention has the following main features and components: [0105] The structure combines solid portions (aiming at mechanical stability) and porous screw/implant (aiming to increase the surface area of the implant, increase the area of bone integration, possibility of coating with cellular carrier agent); [0106] The design considers the load applied in each region of the body, thus generating families of screws/implants with known characteristics; [0107] The porous region allows for the accommodation of cell growth carriers; [0108] The quantity and location of the cell carrier agents are controlled by the geometric shape of the pores induced in the porous section of the piece; [0109] The manufacturing process allows the production of a range of implant/screw geometries within shorter production times than by conventional manufacturing processes.

[0110] Below is a detail of the operation of the present invention: [0111] The function of the screw/implant is to reestablish the patient's motor/masticatory/aesthetic function; [0112] The increase in area caused by the geometry of the macro and microstructure (texturing) of the surface allows bone tissue to occupy these places and increase tissue integration; [0113] Through component loading analysis (biomechanical analysis and finite element simulation), the optimized screw/implant topology is determined; [0114] Once the solid topology has been determined, the porous process is designed, where the pore size, wall thicknesses and other characteristics of the piece are described. [0115] The porous region allows accommodation of carrier agents in such a way that different agents are deposited in different positions of the trabeculated region.

[0116] It is observed that the porous fraction of the implant can be limited due to the need to maintain the region/solid fraction of the implant due to the mechanical loads applied. Also, the reduction of the solid region limits the capacity of the support component to situations of possible overload.

[0117] And, due to the characteristic of neoformation of bone tissue, there is an ideal pore size of 0.3 mm in diameter that can be designed on the part for the functionalization of cell growth having the maximum limit dependent on each part to be produced because it is directly related reduction of mechanical resistance.

[0118] It is important to note that the loads vary according to the position of the screw used in the body.

[0119] Also, the lengths and diameters of the screws/implants are given according to minimize the invasion in the organism and guarantee the intended function.

[0120] The parameters of the trabecular region (sometimes denser, sometimes more porous, with control of geometric characteristics in the design) allow to design/accommodate different amounts of cell carrier agents. It is also possible to change the trabecular geometry between the regions of the implant/screw.

[0121] FIGS. 7 to 14 illustrate views of the screw and the implant, objects of the present invention. In these figures, it is possible to verify the distribution and density of the pores present on the surface and structure of preferred embodiments of the present invention.

[0122] FIGS. 15, 16 and 17 are pictures of the screw and the implant, objects of the present invention.

[0123] In preferred embodiments of the present invention, the following screw models for orthopedic purposes are used: [0124] Monoaxial and polyaxial pedicle screw for fixing the spine; [0125] Cannulated compression screw for fractures and deformities; [0126] Cannulated screw for fractures; [0127] Interference screw for ligament reconstruction; [0128] Herbert type screw to correct fractures and deformities; [0129] Screw for fixing the odontoid; [0130] Acetabular screw.

[0131] The present invention has numerous technical and economic advantages when compared to the state of the art, some of which are listed below:

[0132] Reduction of material by implantable medical device—reduction of the possibility of rejection of the implant (foreign body reaction);

[0133] Greater growth of adjacent bone tissue within the porous microstructure, resulting in better adherence of the implant to the body;

[0134] Design of parts with mechanical characteristics closer to those of the bone tissue where it will be applied, especially considering the elasticity of the part;

[0135] Better adaptation of the tissues adjacent to the implants/screws;

[0136] Add functions and stimulators in controlled positions and quantities in the implants;

[0137] Possibility of the implant being a carrier of drugs and/or biomolecules distributed in the porosities designed on the implant. Thus, there is the additional function of treating a specific site with the use of the aforementioned bioactive molecule or even acting in a combined manner on the site;

[0138] Possibility of the implant being a carrier of stem cells, these distributed in the porosities designed on the implant, causing better fixation and healing of the implant.

[0139] Having described an example of a preferred embodiment of the present invention, it should be understood that the scope of the present invention encompasses other possible variations of the described inventive concept, being limited only by the content of the appended claims, including the possible equivalents therein.