The present invention belongs to the technological fields of Dentistry and Medicine (Orthopedics) and refers to osseointegrated implants and screws with structurally porous surfaces prepared by an additive manufacturing process. Such implants are prepared in order to comprise modifications such as intrinsic porosity with controlled pore size and density and/or with reduced mass in specific regions, which confers several technical advantages.
Furthermore, the present invention relates to the process of preparing said implants and/or screws with an optimized structure for accelerating osseointegration.
Thus, the present invention refers to the use of said implants and screws as carriers of proteins, drugs, stem cells, among other possibilities.
Dental implants and screws, today, are the most modern and used to definitively rehabilitate teeth that have been lost. These are titanium pins/screws that are implanted in the bone and over them prostheses are cemented in composite resin, porcelain or zirconia (or both).
Currently, osseointegrated implants and screws are commonly manufactured by machining or casting (orthopedic). In both cases, the resulting parts go through a machining process and subsequent surface treatment. With machining, the roughness is quite low (and this is usually the goal of the machining process).
It is known that the texturing obtained by these mechanical (blasting) or chemical (acid attack) processes is limited and quite random. Thus, there is no precise control of the desired surface configuration.
The geometry of these components is merely oriented to mechanical resistance, in simple analysis of the clamping force or loading when the function of the planned implant.
Screws are usually used to fix plaques, meshes or mesh to correct bone defects or to rebuild bone tissue due to trauma or tumors.
The shape of the screw varies according to:
Most well-known products, currently on the market, are as follows:
In general, the surface roughness of a dental implant is about 1 μm (Ra, which is an arithmetic mean of the surface) or 10 μm (Rt, which corresponds to the greatest peak-valley distance). The roughness is obtained by blasting with spheres or abrasive particles, and subsequent acid attack (see
Thus, there is a technical limitation in the generation of implant roughness in addition to the little control of the result obtained by traditional processes.
We highlight below some teachings of the state of the art that refer to the present subject:
BR 11 2012 031296 0 refers to implants that may include a base member, such as an acetabular shell or an add-on, which is configured for coupling with an add-on, a flange cup, a mounting member or any other adequate orthopedic display. Any of the implantable components can include one or more porous surfaces. The porous surface can be textured by projections that connect and extend from the surface. The sizes and concentration of the projections can be varied for specific applications to accommodate different patient anatomies and implants. A porous implant can also include one or more solid internal or external portions that stiffen the implant. It also describes that the porous implant can be created using 3D printing technology that uses powdered metal to “print” the modeled implant. In such approach, a foam can be created having a surface profile that includes protrusions and the profiled foam can then be filled in with the sprayed metal to create a porous microstructure with the profiled surface. A foam that does not contain the protrusions can also be used to create the porous microstructure with powdered metal and the desired surface profile with protrusions can then be stamped onto the surface of the porous metal implant.
Document BR 10 2017 006922 2 reveals a tight bone implant, particularly an implant prototyped in titanium or zirconia, or cast in titanium, which turns to the health area, especially dentistry, specifically for rehabilitation treatment within the specialty of implant dentistry, surgery and prosthesis. The obtaining process, in one embodiment, requires a tomography of the patient's jaws, which is then subjected to a software for implant planning and subsequent machining of the mold, which can be done, for example, by machining on machine tools or on a 3D printer, to finally cast in titanium.
Document KR 101635768 describes a method of manufacturing an artificial tooth using a three-dimensional (3D) printer. The 3D printer includes a raw material feed unit, a transfer unit, a print head, a work table and a control unit. The raw material feed unit is to feed a glass wire that serves as a raw material. The transfer unit is to transfer the glass wire fed from the raw material feed unit. The print head is to melt the glass wire transferred by the transfer unit and to discharge the glass wire through a nozzle.
Document CN 207590772, on the other hand, describes a bone-type canine implant that comprises a self-threaded thread segment, a microporous thread segment and a thin thread segment arranged in order from top to bottom. The microporous segment of the structure simulates a spongy trabecular structure of human bone obtained by 3D printing.
Document WO 2019/104853, on the other hand, describes a porous dental implant capable of degrading magnesium ions, comprising an implant-based cell printed by SLM technology of a pure titanium material, in which the implant-based cell has a porous structure and its surface is provided with a spherical hole or a groove. The groove, the spherical hole or the groove of the thread is filled with a degradable layer formed by the instantaneous bonding of the fusion of magnesium particles. SLM (selective laser fusion) is an additive manufacturing method developed especially for 3D printing metal alloys. It creates parts, additively, by fusing particles of metal powder together in a complete melting process.
Document CN 109172050 discloses a porous titanium sheet that can be filled with composites in a biological experiment and a method of preparing this sheet. It is said that the prototyping of the porous titanium sheet is done by 3D printing with process precision 0.025 mm.
Finally, document CN 108236508 discloses a porous dental implant structure with self-expanding grooves with NiTi memory. It is said that the porous structures incorporated in the groove are distributed at the bottom of the root which is done by 3D printing with a memory effect.
Therefore, in the state of the art, there is no solution equivalent to the one presented here in the present invention that combines technical differentials, economic advantages, safety and reliability of reproducibility in the manufacture of implantable medical devices with superficial porous microstructure interspersing the entire solid structure.
Thus, it is an objective of the present invention to provide osseointegrated implants for dental and medical use (prostheses).
It is an objective of the present invention to provide osseointegrated implants and screws with surface structure morphologically with controlled and rougher geometry.
It is an objective of the present invention to provide osseointegrated implants and screws prepared by means of an additive manufacturing process (3D printing).
It is another objective of the present invention to provide osseointegrated implants and screws prepared by means of a process that allows control of the roughness distribution as well as the pore size and morphology.
It is another objective of the present invention to provide osseointegrated implants whose surface presents controlled porosity many times greater when compared to implants prepared by traditional processes.
It is another object of the present invention to provide implants whose surface is plainly distinct, with regions where the roughness is altered according to the stipulated requests or requirements.
It is also another objective of the present invention to provide implants with better integration into the body, due to the microstructure of the surface.
It is, yet, another objective of the present invention to provide implants that provide faster rehabilitation of the patient.
It is, yet, another objective of the present invention to provide implants whose preparation process requires less use of material (if porous, lighter, less material), thus less quantity of product to be implantable (reduction of foreign body to the organism), without compromise the mechanical property requirements for the performance of the intended function.
Furthermore, it is an objective of the present invention to provide osseointegrable implants used as carriers.
It is, yet, another objective of the present invention to provide implants with specific texture that attends the identified need of the place where the implant or screw will be fixed.
The present invention achieves these and other objectives through an osseointegrated dental or orthopedic implant or screw preparation process that comprises the following steps:
a) preliminary preparation of a dental or orthopedic implant or screw (endo-osseous implantology) or selection of 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 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 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.
The present invention achieves these and other objectives by means of an implant or screw obtained by the above process.
Finally, the present invention achieves these and other objectives through the use of this implant and this screw as carriers.
The present invention will be described on the basis of the drawings attached hereafter, which illustrate:
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.
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
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.
Thus, the implant, object of the present invention, comprises a much rougher surface when compared to implants prepared by traditional processes.
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:
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.
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.
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.
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.
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.
The process of the present invention comprises the following steps:
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.
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.
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:
Therefore, the process of the present invention and the products generated by said process (screws and implants with designed structure) offer additional differentials:
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.
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.
The present invention has the following main features and components:
Below is a detail of the operation of the present invention:
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.
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.
It is important to note that the loads vary according to the position of the screw used in the body.
Also, the lengths and diameters of the screws/implants are given according to minimize the invasion in the organism and guarantee the intended function.
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.
In preferred embodiments of the present invention, the following screw models for orthopedic purposes are used:
The present invention has numerous technical and economic advantages when compared to the state of the art, some of which are listed below:
Reduction of material by implantable medical device—reduction of the possibility of rejection of the implant (foreign body reaction);
Greater growth of adjacent bone tissue within the porous microstructure, resulting in better adherence of the implant to the body;
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;
Better adaptation of the tissues adjacent to the implants/screws;
Add functions and stimulators in controlled positions and quantities in the implants;
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;
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.
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.
Number | Date | Country | Kind |
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10 2020 011004 7 | Jun 2020 | BR | national |
Filing Document | Filing Date | Country | Kind |
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PCT/BR2021/050235 | 6/1/2021 | WO |