DENTAL IMPLANT AND SELF-LOCKING FASTENING ELEMENT WITH HETEROGENEOUSPOROUS STRUCTURES, AND METHOD FOR ITS PRODUCTION

Abstract

A dental implant assembly comprising an elongated inner body substantially resembling a tooth root (1-1) and an outer member for securing to a bone of a patient (1-2) having a heterogeneous porous structure adapted to provide bone growth, the inner body and the outer fixation member being formed in one piece, the fastening element being movable between a stored passive position and an extended active position (1-2).

Claims

1. A dental implant assembly comprising an elongated inner body (1-1, 5-1) substantially resembling a tooth root and an outer member for fixing a heterogeneous porous structure bone structure (1-2, 5-4) adapted to provide bone growth, the fixation member being movable between a stored passive position and an extended active position, the inner body and the outer fixation member being formed in one piece.

2. An assembly according to claim 1, wherein the inner body (1-1, 5-1) of the implant comprises an external thread having a thread height H, the fastener is interposed between the turns of the thread and unfolding between the stored passive position and the deployed active position by a distance equal to or greater than the thread height.

3. An assembly according to claim 1 or 2, wherein the fastening element (1-2, 5-4) has a coefficient of thermal expansion greater than that of the body of the implant allowing it a greater lateral deployment of 15 at 40% with respect to that of the internal body at body temperature.

4. An assembly according to claim 3, wherein the material constituting the fastening element (1-2, 5-4) has a coefficient of thermal expansion greater than that of the body of the implant allowing it a greater lateral deployment of 15 to 40% with respect to that of the internal body at body temperature.

5. An assembly according to claims 1 to 4, comprising a removable spacer device of the fastener element which is inserted inside the inner body and which controls the displacement of the fastening element (1-2, 5-4) from the stored passive position to the deployed active position.

6. An assembly according to claim 5, wherein the removable spacer device is a screw for positioning the implant.

7. An assembly according to claims 1 to 6, wherein the fastening element (1-2, 5-4) is connected to the inner body by a breakable connection.

8. An assembly according to one of claims 1 to 6, wherein the fastening element (1-2, 5-4) and the inner body have no connection.

9. The assembly as claimed in one of the preceding claims, in which the fixing element and/or the inner body consist of a composite material formed by a melting of microparticles of a first material with a given melting point, and nanoparticles of a second material with a higher melting temperature, forming a dendritic zone network of the first material at the micron scale interspersed with nanometric filamentous zones of the second material.

10. An assembly according to claim 9, wherein the first material is a metal.

11. An assembly according to claim 10, wherein the first material is or comprises titanium.

12. An assembly according to claim 11, wherein the second material is a ceramic.

13. An assembly according to claim 12, wherein the second material is a zirconia.

14. The assembly as claimed in claim 13, wherein the second material is an yttria zirconia.

15. An assembly according to one of the preceding claims, wherein the inner body has a hollow frustoconical shape defining a wall thickness, provided with an external thread, and comprises two opposite grooves made in its wall thickness and in a helical profile, the fastening element having the form of a thick ribbon twisted according to the helical profile of the two grooves and a shape complementary to those ci.

16. An assembly according to claim 15, wherein the fastening element and/or the inner body comprises a longitudinal central recess passing through a spacer device of the fastener.

17. A method of manufacturing a dental implant assembly according to one of the preceding claims, by stacking layers of metal powders and/or non-metallic fused selectively by concentration of an energy source comprising a step of preparing the mobility of the fastener relative to the inner body.

18. Method according to the preceding claim, wherein the step of preparing the mobility of the fastener comprises a step of forming a bridge of breakable material between a portion of the assembly forming the inner body and a portion of the assembly forming the fastener during manufacture by stacking layers.

19. The method of claim 17, wherein the step of preparing the mobility of the fastener comprises a step of forming the portion of the assembly forming the fastener with a material having a coefficient of expansion thermal superior to that of the body of the implant allowing him a lateral deployment superior of 15 to 40% with respect to that of the internal body with temperature body.

20. The method of claim 17 or 19, wherein the step of preparing the mobility of the fastener comprises a step of forming the portion of the assembly forming the inner body and the portion of the assembly forming the fixing element without a bridge of material between them, the part of the assembly forming the fastening element being manufactured with an internal recess allowing it to be radially deployable under the effect.

Description

DETAILED DESCRIPTION OF THE FIGURES

[0051] The invention will now be described in more detail with the aid of the drawings which illustrate preferred embodiments of an assembly according to the invention. On these drawings:

[0052] The FIG. 1 shows the dental implant and the fixing element according to a first exemplary embodiment

[0053] The FIG. 2 Illustrates the different steps of the digital flow of the embodiment of the dental implant and fastener assembly according to FIG. 1

[0054] The FIG. 3 illustrates a first embodiment of the unit cell and its implementation in the fixing element of FIG. 1

[0055] The FIG. 4 Illustrates the placement of the dental implant and fixation element (left) and its self-locking on the implant wall (on the right).

[0056] FIG. 5 illustrates a second embodiment of the dental implant assembly and fixing element according to the invention

[0057] FIG. 6 represents a cross-sectional and longitudinal view of an MRI performed on a user wearing the implant of FIG. 5 after 8 weeks of bone growth (transverse section and longitudinal section, the bone being represented in dark and implant in clear)

[0058] The present invention describes a system and its method by additive manufacturing of dental implants with heterogeneous and self-locking porous structures which advantageously provides a double answer to the problems inherent in dental implantology, namely osseointegration and mobility of the implant. during his pose. For this, the present invention provides a self-locking dental implant with heterogeneous porous structures.

[0059] The dental implant described in the present invention is composed of a central body which represents the root rooted in the jawbone, the head of the implant can be rounded, flat, hollow, or any particular shape to receive the prosthetic pillar. In another embodiment, the implant may be integral with the implant abutment. The one-piece realization of the implant and the prosthetic abutment will be done by additive manufacturing, particular angles of curvature between the implant and the abutment are calculated following a digital processing of three-dimensional images of the morphology of the jaw.

[0060] It is self-locking in the bone in which it is implanted thanks to the porous bone fixation element, which is made movable between a passive row position allowing insertion of the implant into a perforation made in the bone, and a position deployed active where this porous element fills the cavities existing between the internal body of the implant and the bone and will be colonized by this bone during bone growth.

[0061] This mobility of the fastener may be caused by thermal expansion, and/or by a tool as will be explained in more detail in the following.

Porous Fastening Element

[0062] The fastener may be in the form of a heterogeneously porous helical-shaped coating for certain threaded implants, but this coating may be of different shapes and geometries that encase part or all of the implant. dental implant being preferably disposed in the portion of the dental implant in contact with the bone.

[0063] Said structure has a porosity of between 30% and 80%, a pore size of between 100 m and 500 m and a pore distribution of between 500 m and 700 m with total interconnectivity. In a preferred embodiment the porosity between 60% and 70%, the pore size between 200 microns and 300 microns with a distribution of porosity between 100 microns and 600 microns and a total inter connectivity. Its parameters are thus close to the characteristics of the human bone in the maxillary and the mandible.

Internal Body of the Implant

[0064] The body of the dental implant and its fixing element are made by stacking layers of metallic or nonmetallic powder, selectively fused together. In the case of titanium/aluminum/vanadium metal powder, the thickness of the layers is generally 30 m. One of the additive manufacturing techniques selected for our example is SLM technology, this embodiment is not limiting, other deposition technologies can be deployed.

Achievement by Addition

[0065] A digital file of the dental implant is produced by a three-dimensional design software either according to standard models and standards or according to a particular embodiment: in this case, the shape of the dental implant, namely its height, its low section, its high section are determined more precisely.

[0066] In another embodiment, the dental implant may have the exact shape of the tooth, this mode is preferred in the case of replacement of a tooth just after extraction. A customized implant is thus produced according to the morphology and the mechanical properties of the tooth of the patient to be replaced and/or of the bone in which the implant will be integrated.

[0067] In this file, the fixing element is predefined with a particular thickness of between 1 and 2 mm, in a preferred embodiment the thickness is between 0.8 mm and 1.5 mm.

[0068] Several forms of porosity can be selected with the possibility of defining pore distribution zones of different sizes.

[0069] Ideally, the porous structure forming the fixing element has a porosity of between 30% and 80%, a pore size of between 100 m and 500 m and a pore distribution of between 500 and 700 m with total interconnectivity.

[0070] In a preferred embodiment the porous structure has a porosity between 60% and 70%, the pore size between 200 microns and 300 microns with a distribution of porosity between 100 and 600 microns and a total inter connectivity.

[0071] The basic cell or unit cell constituting the porous structure made by stacking layers, is of geometric shape in three dimensions (x, y, z), the unit cell is formed by at least three edges with an angle opening d at least 10, such as a trihedron, and the unit cell may be of regular or irregular shape in the form of a pyramid, tetrahedron, cubic, octahedron, icosahedron, dodecahedron and without shape limitation. In a preferred embodiment, the unit cell will be of reinforced dodecahedron form.

[0072] In another embodiment, the unit cell is formed of 12 edges with edge opening angles of 30 to the vertical axis or construction axis. The edges can be regular or irregular depending on the density of the mesh and the desired porosity.

[0073] The material used for the production of such an implant is a biocompatible material of pure metal or metal alloys of the cobalt, tantalum, niobium chromium type, metal-ceramic or organo-metal or organo-ceramic compounds or a metal organo-ceramic combination.

[0074] For the realization of the internal body, two alloys of materials have been preferentially used:

[0075] a titanium alloy aluminum vanadium Ti6Al4V grade 23, with an oxygen content<0.2%,

[0076] A combination of a titanium alloy advantageously mixed with a zirconia-based material.

[0077] For the realization of the fixing element, three alloys were used:

[0078] A titanium alloy aluminum vanadium Ti6Al4V grade 23, with an oxygen content<0.2%, [0079] A combination of a titanium alloy advantageously mixed with a zirconia-based material

[0080] A combination of a titanium alloy advantageously mixed with a nickel-based alloy

[0081] And in a preferred embodiment, the inner body and/or the porous fastener consist of a biocompatible material containing a zirconia-titanium composite/binary material with zirconia powder concentrations of between 5% and 25%, which is obtained during the shaping of this internal body and/or fastening element by additive manufacturing by selective melting of layers of powders, powders advantageously consisting of a mixture of nanometric particles of zirconia (or any other ceramics) and particles micrometric titanium (or any other metal).

[0082] Once the shapes of the inner body and of the fixing element have been determined, the porosity of the selected fastening element, the unit cell defining this porosity, also chosen, the constituent materials of these chosen, and the mobility means of the determined fastening element, the embodiment by additive manufacturing, and in a preferential mode by the SLM technology can be launched.

[0083] The dental implants system with heterogeneous porous structures is made by selective fusion of biocompatible metal powder with a particular embodiment of the implant surface.

[0084] The autoblocking system of the implant can be achieved by a mechanical means external to the implant or internal and then performed simultaneously with the implant and which pushes the helical portion to the bone seat of the implant.

[0085] The fixing element which advantageously has a helical profile in order to be distributed over the whole of the external surface of the implant, and which is made movable between the inactive, stored and deployed active positions, can be integral (a). or not integral (b) of the central nucleus or internal body of the dental implant:

[0086] (a) Solidary: the helicoidal part is held by at least four integral fixation points of the central pillar or inner body, at the laying of the dental implant, a suitable tool comes to chase the fixing points in order to release the helicoidal part which just stick to the walls of the dug out of the implant. In this case, it may be provided that the porous fastening element is made in a pre-stressed form and fixed in its pre-stressed form to the inner body by the attachment points, so that when the fixation, it can be released and expand naturally with respect to the internal body to adopt its active position deployed

[0087] (b) Not secured: the assembly of the helical portion on the central pillar is for example by lateral compression by a suitable tool and the installation of the dental implant, the assembly is released.

[0088] Other means of blocking the fastening element in the hollow formed in the bone, can be envisaged, for example, the thermal fixation by thermal expansion of the fastening element when inserted into the bone. of the patient and subjected to his body temperature (it is then expected a thermal expansion of the fastener greater than that of the internal body of the implant, at least 20% for example) or chemical fixation in reaction to an additive or in contact with the implant medium. For example, the fastener may be a moisture-responsive polymer that will swell when exposed to the moisture of the patient's body once inserted into the bone.

[0089] Another mode of blocking can be envisaged, with a stoichiometric mixture of nickel/titanium forming Nitinol, a shape memory alloy which has a coefficient of thermal expansion and elasticity higher than titanium. In this case, the porous fixing element may consist of Nitinol and the internal titanium body.

First Illustrated Embodiment

[0090] The dental implant described in the present invention is composed of a central body which represents the core of the implant (1-1), the head of the central body may be rounded, flat, hollow, or any particular shape to receive a implantary abutment, in another mode the implant core may be integral with the implant abutment and made in one piece in additive manufacturing with particular angles of curvature according to the morphology.

[0091] A coating with heterogeneous porous structures (1-2) of helical shape for some implants but this coating can be of different shapes and geometries that come in dressing of part or all of the dental implant.

[0092] In the example of FIG. 1, the inner body 1-1 has a frustoconical shape consisting of a flared base, a rounded head and an intermediate portion formed by a vertical plate whose side edges are crossed by a flat strip arranged in a spiral shape, as best seen in FIG. 2 under the reference 2-2. The porous fastening element here consists of a spiral-shaped strip, complementary to the turn formed by that of the inner body and interposed between the outer edges of two consecutive turns. This FIG. 1 shows an exploded view of the implant according to the invention knowing that it is preferably obtained in one piece with its inner body and its porous fastening element nested one inside the other.

[0093] FIG. 2 represents the preliminary steps to the actual realization, steps of definition of basic shapes from which to realize the object. Thus, it is defined numerically the external envelope of the implant to be made without worrying about the internal structure of the body as described above, nor the pores of the fixing element.

[0094] The particular structure of the inner body (2-2) and that of the fastening element are then defined, again without the pores (2-3).

[0095] Different porosities are then defined for the fastener (2-4, 2-5, 2-6).

[0096] And after having chosen the porosity adapted to the particular case (as a function of the mechanical properties envisaged with such a structure and such porosity), a file is defined which joins the particular internal body with its complete structure, and the fixing element with porosity. desired (2-7).

[0097] The implant is then made by additive manufacturing according to the SLM technology already described, the implant (2-1) is made by a three-dimensional design software according to the morphology of the patient, the height and the section of the implant are thus defined.

[0098] In this example, the fixing element is made movable between the position shown in FIG. 4 on the left: passive position row, and the active position deployed (FIG. 4 right) in that it is independent (unbound) to internal body, and consisting of a material having a coefficient of thermal expansion greater than 15 to 40%, preferably 15 to 25% of that of the material constituting the inner body, at body temperature (of the order of 37 C.). One could also provide a fastening element made integral with the inner body by securing points breakable from a threshold, crossed threshold when the fastener expands thermally exposed to the body temperature of the user. We will then choose the material according to this threshold.

[0099] In this case, the fastening element expands so that its outer wall flushes the ridges of the flat spiral band of the body and thus comes into contact with no gap in the bone cavity.

[0100] It can be provided that the fastening element is connected to the body by a bridge of breakable material (for example of smaller thickness) or a chemical bridge.

[0101] Or that the fastening element can be spaced radially relative to the inner body that contains it.

[0102] This is the embodiment shown in FIG. 5.

[0103] The porous part (2-3) is predefined with a particular thickness of between 1 and 2 mm from the central body of the implant (2-2).

[0104] Several porosity shapes can be selected (2-4; 2-5; 2-6) with the possibility of setting the pore distribution zones of different sizes.

[0105] The basic cell or unit cell (3) is of geometric shape in three dimensions (x, y, z), the unit cell is formed by at least three edges (3-1), with a rounded-shaped cladding (3-). 2), this form is not limiting, with an angle opening of at least 10, and the unit cell may be of regular or irregular shape in the form of a pyramid, tetrahedron, cubic, octahedron, icosahedron, dodecahedron and without limitation of form.

[0106] The distribution of unit cells (3-3) can be regular or irregular, with opening angles of at least 10. After dressing the unit cells (3-4) the porous part is formed.

[0107] An implant diameter drill tapped the bone, because of the low density and natural porosity of the maxillary and mandibular bone, the threading is approximate. At the mouth of the dental implant (4-2), small cavities appear between the body of the implant and the bone see detail (4-1). Upon release of the fastener (4-4) all small cavities are filled, see detail (4-3).

[0108] The numerical execution flow of tasks is summarized in FIG. 2:

[0109] Step 1: The digital file of the dental implant is made by a three-dimensional design software (2-1), the shape can be standardized according to a pre-defined or customizable model.

[0110] Step 2: delimiting the part of the fixation element (2-3) and the solid part representing the body of the implant (2-2),

[0111] Step 3: Generate a type of unit cells or a combination of said base cells (2-4; 2-5; 2-6). Which cells are characterized by the geometry thus produced has the advantage of controlling the porosity and its density.

[0112] Step 4: Realization of the central implant assembly+fixing element (2-7) having a porous surface advantageously heterogeneous.

Second Embodiment

[0113] In this example, the inner body (5-1) has a hollow frustoconical shape defining a wall thickness, provided with an external thread 5-2, and comprises two opposite grooves 5-3 made in its wall thickness and following a helicoidal profile, the fastening element 5-4 having the shape of a thick ribbon twisted according to the helical profile of the two grooves and a shape complementary to those ci.

[0114] The fastening element 3-4 comprises an upper and central longitudinal recess 5-5 for the passage of a spacer, such as the screw for placing the implant.

[0115] The first two views of this FIG. 5 separately represent the inner body 5-1 and the fastening element 5-4 for a better understanding of their structure, but the one-piece form is the one shown in tearing view and in normal view on the third and fourth view.

[0116] It can be seen in FIG. 6, which shows a cross-sectional and longitudinal view of an MRI performed on a user wearing an implant according to the invention after 8 weeks of bone growth, that the bone has penetrated deeply into the heart of the bone. implant, and that the bone portion having penetrated the implant is of equivalent quality to that of the cortical bone surrounding the implant and therefore of good quality.

[0117] Example of the implant parameters of the Dental Implant and Fixation Device Set on an SLM 125 HL machine from the manufacturer SLM SOLUTIONS GMBH

TABLE-US-00001 Parameter type Parameter type Parameter type Dental implant Dental implant Dental implant Fixing element Fixing element Fixing element Powder type Powder type Powder type Titanium (Ti6Al4V) Titanium (Ti6Al4V) Titanium (Ti6Al4V) Titanium (Ti6Al4V) Titanium (Ti6Al4V) Titanium (Ti6A14V) Laser power in full Laser power in full Laser power in full area (w) 400, 300 area (w) 400 300 area (w) 400 300 Laser low power (w) Laser low power (w) Laser low power (w) 200 100 200 100 200 100 Laser power in porous Laser power in porous Laser power in porous zone (w) 100 zone (w) 100 zone (w) 100 Exposure (ms) 350 Exposure (ms) 350 Exposure (ms) 350 380 380 380 Exposure limit (ms) Exposure limit (ms) Exposure limit (ms) 300 350 300 350 300 350 Hatching distance Hatching distance Hatching distance (m) 25 10 (m) 25 10 (m) 25 10 Powder type Powder type Powder type Titanium/zirconia Titanium/zirconia Titanium/zirconia Titanium/nickel Titanium/nickel Titanium/nickel Laser power in full Laser power in full Laser power in full area (w) 400 200 area (w) 400 200 area (w) 400 200 Low power of the Low power of the Low power of the laser (w) 200 80 laser (w) 200 80 laser (w) 200 80 Laser power in porous Laser power in porous Laser power in porous zone (w) 80 zone (w) 80 zone (w) 80 Exposure (ms) 350 Exposure (ms) 350 Exposure (ms) 350 380 380 380 Exposure limit (ms) Exposure limit (ms) Exposure limit (ms) 300 350 300 350 300 350 Hatching distance Hatching distance Hatching distance (m) 25 10 (m) 25 10 (m) 25 10 Powder type Powder type Powder type Titanium/zirconia Titanium/zirconia Titanium/zirconia Titanium/zirconia Titanium/zirconia Titanium/zirconia Laser power in full Laser power in full Laser power in full area (w) 400 400 area (w) 400 400 area (w) 400 400 Low power of the Low power of the Low power of the laser (w) 200 125 laser (w) 200 125 laser (w) 200 125 Laser power in porous Laser power in porous Laser power in porous zone (w) 125 zone (w) 125 zone (w) 125 Exposure (ms) 380 Exposure (ms) 380 Exposure (ms) 380 400 400 400 Exposure limit (ms) Exposure limit (ms) Exposure limit (ms) 280 320 280 320 280 320 Hatching distance Hatching distance Hatching distance (m) 30 25 (m) 30 25 (m) 30 25

[0118] Preferably, it is recalled that:

[0119] the assembly according to the invention is produced by stacking layers of metallic or non-metallic powders, fused selectively by concentration of a source of energy.

[0120] the assembly according to the invention is characterized in that said fixing element comprises a heterogeneous structure having a porosity of between 60% and 80%.

[0121] the assembly according to the invention is characterized in that said fixing element is formed by a multiple of a unit cell, said unitary cell is formed by at least three edges and opening angles of at least 10.

[0122] the assembly according to the invention is characterized in that said dental implant has either a cylindric-conical geometry or the morphological shape of the tooth.

[0123] the preferred material according to the invention is derived from the fusion of a homogeneous and stable mixture of microscopic titanium or Ti6Al4V powders and nanoscopic yttria zirconia powders in which: [0124] the content of titanium or Ti6Al4V is between 60 and 95.5% [0125] with a particle size of between 5 and 10 microns [0126] the yttria zirconia content is between 13.5 and 30%

[0127] with a particle size of between 30 and 70 nm and a median size of between 65 and 85 nm and a minimum size of greater than 20 nm.