Implantable temporomandibular joint prosthesis and corresponding manufacturing method - Patents.com

Abstract

The present invention relates to an implantable temporomandibular joint prosthesis (100), comprising a first implant part (10) having an artificial condyle (12) and attachable to a mandible (30), and a second implant part (20, 20') having an articular surface (22, 22') and attachable to a skull (40), said articular surface (22, 22') forming an abutment for said artificial condyle (12), said second implant part (20, 20') comprising a first component (24, 24') made of a metallic material and attachable to said skull (40), and a second component (27, 27') made of a plastic material and forming said articular surface (22, 22'), The first component (24, 24') has a first connecting surface (25, 25') and the second component (27, 27') has a second connecting surface (28, 28'), and the first connecting surface (25, 25') and the second connecting surface (28, 28') are mutually engaged with each other and joined together in one piece.

Description

[Technical Field]

[0001] The present invention relates to an implantable temporomandibular joint prosthesis comprising a first implant part having an artificial condyle attachable to the mandible and a second implant part having an articular surface attachable to the skull, the articular surface forming an abutment for the artificial condyle. The present invention further relates to a corresponding method for manufacturing the implantable temporomandibular joint prosthesis. [Background technology]

[0002] The temporomandibular joint (TMJ) is one of the most used and most important joints in the human body. It plays a vital role in guiding the movement of the mandible (lower jaw) during chewing, speaking, swallowing, and stress management. It is constantly moving, even during sleep, due to swallowing. For the TMJ to be able to perform its own series of movements, the shape of the articular surfaces, the condition of the teeth, their position, shape, and the muscles of mastication must form a functional system, which is prone to some degree of dysfunction due to its many components. The left and right TMJs always work together and, in this respect, form a functional unit.

[0003] However, if functional disorders such as functional limitations or diseases occur in the region of the temporomandibular joint, the patient's quality of daily life can be significantly impaired. In this case, restoration of the correct joint structure is usually only possible by surgical solutions, i.e., by excision of the defective joint and its replacement with a temporomandibular joint prosthesis.

[0004] A temporomandibular joint prosthesis is known, for example from US Pat. No. 5,629,999, which provides a mechanism that allows a combination of translational and rotational movements between the skull and the mandible, which movements involve sliding movements between surfaces. However, wear can occur.

[0005] The object of the present invention is to provide an improved implantable temporomandibular joint prosthesis, whereby the sliding movement of the surfaces takes place as reliably and safely as possible, and at the same time with little wear. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] European Patent No. 3003225 Summary of the Invention

[0007] This object is achieved by an implantable temporomandibular joint prosthesis having the features of claim 1. The solution according to the invention therefore consists in the fact that, in particular for temporomandibular joint prostheses of the initially mentioned type, the second implant part comprises a first component made of a metallic material and attachable to the skull, and a second component made of plastic and forming an articular surface, the first component having a first connecting surface and the second component having a second connecting surface, the first connecting surface and the second connecting surface being mutually engaged with each other and connected together.

[0008] Thus, the implantable temporomandibular joint prosthesis of the present invention provides reliable tribological mating at the articular surface forming the abutment for the condyle by providing multiple components on the second implant part that engage with each other and are integrally connected via their connecting surfaces, resulting in a stable, low-wear articular surface for tribological mating between the metal and plastic components. Notably, no "snap-in" or form-fit mechanism is provided; instead, the abutment is in the form of an open-shell sliding surface based on the actual surface of the human temporomandibular joint. The natural muscle chain holds the two implant parts in place, allowing for realistic restoration of joint function.

[0009] The condyles and temporal bone remain in their 3D contours, and therefore the implantable temporomandibular joint prosthesis according to the present invention is patient-specific, expandable, and pathology-safe. Preferred developments of the implantable temporomandibular joint prosthesis according to the invention can be found in the associated dependent claims.

[0010] In a preferred development of the temporomandibular joint prosthesis, the first connecting surface can be provided with a recess in which a protrusion arranged on the second connecting surface engages, so as to achieve a form fit between the two connecting surfaces of the first component that is durable and can be stressed against lateral sliding.

[0011] In a further preferred development, the recesses of the first connecting surface of the first component and the corresponding protrusions of the second component can be homogeneous or heterogeneous to ensure a form-fit of the connecting surfaces. Here, the recesses can be heterogeneous, both in terms of their shape and their distribution on the connecting surfaces. For example, a homogeneous variant can consist of a homogeneous arrangement of square-section recesses in both directions of the extension of the connecting surface, while a heterogeneous variant can be designed with multiple recess types, for example, extending in different directions on the connecting surface in different numbers or breaking the homogeneity in some other way. This also applies, conversely, to the aforementioned protrusions as elements of the second connecting surface that are complementary to the recesses.

[0012] In a further preferred development of the temporomandibular joint prosthesis according to the invention, the size of the recess in the first connecting surface of the first component can be, for example, between 1 μm and 2000 μm. A wide size range is therefore covered with respect to the individual dimensions of the particular recess. However, other individual dimensions are also conceivable.

[0013] In a further preferred development of the temporomandibular joint prosthesis according to the invention, in which the tribological pairing of the joint has minimal space requirements, the first and second connecting surfaces can be in the form of mutually matching surfaces that substantially overlap each other, so that the joint surfaces can be provided exactly to the required extent.

[0014] In another preferred development, the first and second connecting surfaces can be concave to ensure a natural range of motion with the temporomandibular joint prosthesis according to the invention, although different curvatures with different radii of curvature and different directions, in particular mutually perpendicular directions, are also conceivable.

[0015] In a further preferred development, the two components of the second implant part can be connected in a particularly stable manner in that the first and second components form a molten composite via their mutually engaging connecting surfaces. In addition to the form-fit achieved by the shape of the connecting surfaces, the stability is based in particular on an integral bond, which can be achieved, for example, by applying heat to the connecting surfaces (possibly additionally under pressure and / or vacuum).

[0016] A further preferred development of an articulating surface with very good sliding properties is that the first component is made of titanium or a titanium alloy and the plastic of the second component is made of a thermoplastic, in particular PE-UHMW as the thermoplastic. However, other combinations of metallic and plastic-like materials are also conceivable.

[0017] In another preferred development, in which the articular surfaces form a particularly tractable tribological pairing with the condyles, the first implant part can be made of ceramic, PEEK material, metallic material or a combination of these materials.

[0018] In a further preferred development, the first component can have an edge region that at least partially grips the second component to prevent lateral slippage during normal movement. The edge region provides additional stability of the connecting surfaces relative to each other. In this regard, the edge region can be located at the lateral ends of the articular surface, while the anterior and posterior surfaces of the articular surface can be devoid of edge regions. However, other configurations of the edge region are also contemplated.

[0019] In a further preferred development, the first and second implant parts can be removably attachable to the mandible and skull, respectively, by means of first and second attachment parts, so that the two implant parts of the temporomandibular joint prosthesis according to the invention can be properly aligned relative to each other and at the same time stably attached to the body regions facing each other, thereby also allowing them to be easily removed or replaced later.

[0020] In a further preferred development, the first and second attachment parts can each have a hole arrangement through which the associated fastening means can engage with the jaw and skull structures, respectively. The respective hole arrangements can be adapted to the respective local conditions, both in terms of the positioning and the number of holes. For example, the first attachment part of the first implant part can be provided with six holes evenly spaced on the attachment part, while the hole arrangement of the second attachment part of the second implant part is provided with only four holes. However, other hole arrangements are also conceivable. For example, screws as fastening means can be threaded through the holes of the hole arrangement. The fastening means are not limited to screws.

[0021] The above object can also be achieved by a method for manufacturing an implantable temporomandibular joint prosthesis, the method comprising at least the steps of: providing a first implant part having an artificial condyle attachable to the mandible; providing a second implant part having an articular surface attachable to the skull, the articular surface forming an abutment for the artificial condyle, the second implant part having a first component made of a metallic material attachable to the skull, and a second component made of plastic forming the articular surface; and mutually engaging and connecting a first connecting surface of the first component to a second connecting surface of the second component to form an integral connection.

[0022] The interengaging integral connection of the metal and plastic components creates a stable articulation surface for the tribological pairing. In a preferred development of the manufacturing method according to the invention, which improves the stability and durability of the articular surface, heat and pressure and / or vacuum are applied to the first and second components during connection of the first and second connecting surfaces.

[0023] In a further preferred development, the first component and the second component melt together during connection to form a molten composite, and the components are thus joined together by an integral joint.

[0024] In a further preferred development of the manufacturing method according to the invention, the molten composite is formed at the first and second connecting surfaces by inserting the first component into a melt mold and at least partially filling the volume enclosed by the first component in the region of the articular surfaces with the plastic of the second component in powder form before applying heat, pressure and / or vacuum.

[0025] In a further preferred development of the manufacturing method according to the invention, the melt mold is multi-part and completely surrounds the first and second components while connecting them to one another, forming a molten composite, so that the components are properly connected together and can then be released from the melt mold without difficulty.

[0026] The above configurations and developments can be combined with one another as appropriate, as required. Further possible configurations, developments and implementations of the invention also encompass combinations of features of the invention not explicitly mentioned, which features are described above or below in relation to the exemplary embodiments.

[0027] The invention is explained in more detail below on the basis of exemplary embodiments in the figures of the drawing, here shown partly in schematic views. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a perspective side view of a first embodiment of a temporomandibular joint prosthesis according to the present invention, the embodiment including first and second implant parts in an implanted state; [Figure 2a] FIG. 2 is a perspective side view of the first component of the second implant part of the first embodiment. [Figure 2b] FIG. 10 is a perspective side view of the second component of the second implant part of the first embodiment. [Figure 3a] FIG. 10 is a perspective side view of a first component of a second implant part of the second embodiment. [Figure 3b] FIG. 10 is a perspective side view of a second component of a second implant part of the second embodiment. [Figure 4] 10 is an exploded perspective side view of a third embodiment, showing a first component of a second implant part being inserted into a molten mold for connection to the second component. [Figure 5a]10A-10C are perspective side views of a third embodiment, illustrating the connection of a first component of a second implant part to a second component in a fused mold in a time sequence; [Figure 5b] 10A-10C are perspective side views of a third embodiment, illustrating the connection of a first component of a second implant part to a second component in a fused mold in a time sequence; [Figure 5c] 10A-10C are perspective side views of a third embodiment, illustrating the connection of a first component of a second implant part to a second component in a fused mold in a time sequence; [Figure 5d] 10A-10C are perspective side views of a third embodiment, illustrating the connection of a first component of a second implant part to a second component in a fused mold in a time sequence; [Figure 6] FIG. 10 is a perspective side view of the back side of the second implant part with the connected components of the fourth embodiment. [Figure 7] FIG. 10 is a perspective side view of the back side of the second implant part with the connected components of the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0029] In all figures, identical or functionally identical elements and devices are designated by the same reference numerals unless otherwise stated. FIG. 1 shows a perspective side view of a first embodiment of a temporomandibular joint prosthesis according to the invention, with first and second implant parts in an implanted state.

[0030] 1 shows an implantable temporomandibular joint prosthesis, generally designated 100. The implantable temporomandibular joint prosthesis comprises a first implant part 10 and a second implant part 20, which together form a tribological pair. The first implant part 10 is attached to the illustrated mandible 30 (mandible) and comprises a condyle 12 at its end facing the second implant part 20. The second implant part 20 is attached to the zygomatic bone (os zygomaticum) of the skull 40 and comprises an articular surface 22. The articular surface 22 faces the condyle 12 and forms an abutment for the condyle 12 of the first implant part 10.

[0031] The second implant part 20 has a first component 24 made of a metallic material and attached to the skull 40, while the articular surface 22 is formed from a second component 27 made of plastic. The first component 24 has a first connecting surface 25, and the second component 27 has a second connecting surface 28 (see FIGS. 2 and 3). These connecting surfaces are not visible in FIG. 1 because the connecting surfaces 25, 28 face each other and are integrally connected by mutual engagement with each other. Therefore, only the articular surface formed on the side facing away from the connecting surfaces 25, 28 and facing the viewer is visible in FIG. 1.

[0032] In the second implant part 20, the first component 24 is made of titanium and the plastic of the second component 27 is made of a thermoplastic material, for example PE-UHMW (ultra-high molecular weight polyethylene), while the first implant part 10 is made of, for example, titanium. The first component 24 and the second component 27 of the second implant part 20 form a molten composite 50 via their mutually engaging connecting surfaces 25, 28.

[0033] In the first component 24 of the second implant part 20, an edge region 21 is formed on the articular surface 22, and the edge region 21 locally grips around the articular surface 22 on the side of the second implant part 20 facing the observer and on the side of the second implant part 20 facing away from the observer.

[0034] 1 further shows that the two implant parts 10, 20 are removably attached to the mandible 30 and skull 40 by respective attachment parts 32, 42, i.e., a first attachment part 32 and a second attachment part 42. The first attachment part 32 has a first hole arrangement 34 and the second attachment part 42 has a second hole arrangement 44 through which screws as fixation means 38, 48 pass 36, 46 to grip the structures of the mandible 30 and skull 40, respectively.

[0035] The first implant parts 10 are designed like a flat frame, the curvature of which follows that of the ascending ramus of the mandible 30, and are fixed to the ascending ramus of the mandible 30 by means of six screws 38 which reach through equally spaced holes 36 of a first hole array 34. At their ends facing away from the condyles 12 and approximately in the middle of the condyles 12, the first attachment parts 32 each have a web 39 arranged thereon which protrudes laterally from the attachment part and grips around the bone of the mandible 30.

[0036] The second implant part 20 has a second mounting part 42 in a region of the second implant part 20 facing away from the articular surface 22. The second mounting part 42 has a second array 44 of evenly spaced holes 46 extending centrally from the first connecting surface 25 of the first component in a direction facing away from the second connecting surface 28. A screw 48 as a fixation means holds the second implant part 20 to the cheekbone of the skull 40. Furthermore, a web 49 is arranged at the anterior end of the second mounting part 42 for gripping around the cheekbone of the skull 40.

[0037] 2a) and 2b) show perspective side views of the first and second components of the second implant part 20 of the first embodiment, as already partially described in relation to FIG.

[0038] According to FIG. 2a) the recesses 26 of the first connecting surface 25 are evenly distributed, and according to FIG. 2b) these are accommodated in the connected state by cubic protrusions 29 of the second connecting surface 28.

[0039] 2a) and 2b) show perspective side views of the first and second components of the second implant part 20 of the first embodiment, as already partially described in relation to FIG.

[0040] The second embodiment differs only with regard to the design of the recess 26' on the first component 24' and the associated protrusion 29' on the second component 27'. Figure 3a) shows the first component 24' with the first connecting surface 25' and the edge region 21', this first component 24' facing the viewer. It is therefore clearly visible the recess 26' into which the protrusion 29' according to Figure 3b) arranged on the second connecting surface 28' engages when connected to the second connecting surface 28'.

[0041] The protrusions 29' of the second connecting surface 28' according to FIG. 3b) are in the form of raised polylines, which differ from one another in shape and are heterogeneous in this respect. The connecting surfaces 25, 25', 28, 28' of the first component 24, 24' and the second component 27, 27' are in the form of overlapping, mating surfaces. Additionally, the connecting surfaces 25, 25', 28, 28' of the first component 24, 24' and the second component 27, 27' each have a concave cross-section and a curvature with a varying radius of curvature. Additionally, the second implant part 20, 20' has an edge region 21, 21' at the articular surface 22, 22' that locally grips around the articular surface 22, 22'.

[0042] Figure 4 is an exploded perspective side view of a third embodiment, in which a first component of a second implant part is inserted into a molten mold for connection to the second component. Figures 5a-5d are perspective side views of the third embodiment, in which a timeline is shown of connection of the first component to the second component of the second implant part in the molten mold.

[0043] 4 and 5 show a schematic representation of one embodiment of a method for manufacturing the second implant part 20, 20′ of the temporomandibular joint prosthesis 100, which will be described with reference to the second implant part 20. According to FIG. 4, the first component 24 of the second implant part 20 is inserted into a melt mold 52 so as to be connectable to the second component 27. The melt mold 52 is a cylindrical mold comprising a bottom part 53, a middle part 55, and a cover part 56. The bottom part is formed with a support element 54 that supports the first component 24 of the second implant part 20 during insertion, and the middle part 55 grips the first component 27. For the connection of the components 24, 27, a volume 59 surrounded by the first component 24 at its first connection surface 25 is filled with powdered plastic of the second component 27 (not shown in FIG. 4) to form the second component 27 shown. For connection under application of heat, pressure and vacuum, the molten mold 52 is closed by a stamped lid portion 56, the mold surface facing the first component being curved with a curved region 57 in the direction of the first component 24 located in the molten mold 52.

[0044] 5a)-5d) show the time sequence of the melting of the components already outlined above. FIG. 5a) shows a lower part 53 of a substantially cylindrical melt mold 52, inside which a support part 54 is provided for supporting the first component 24 of the second implant part 20 that is inserted into said melt mold 52. FIG. 5a) further shows two holding protrusions 58 arranged relative to each other on the end edge facing the middle part 55 (not shown). In FIG. 5b), said middle part 55 grips around the first component inserted into the melt mold 52, the curvature of which in the direction of the lower part 53 forms a volume 59. The volume portion 59 is partially filled with the second component 27 in powder form in FIG. 5c), followed by application of heat, pressure and vacuum in FIG. 5d), so that the molten composite 50 can be formed into the second implant part 20 after the molten mold 52 is closed by a lid 56 having a lid region 57 that bulges towards the bottom part 53.

[0045] Figure 6 shows a perspective side view of the rear side of a second implant part with connected components of a fourth embodiment. Figure 7 shows a perspective side view of the rear side of a second implant part with connected components of a fifth embodiment.

[0046] It will be appreciated that although the first and second connecting surfaces 25, 25', 28, 28' on the two second implant parts 20, 20' are designed differently, they are outwardly identical and in particular provide articular surfaces 22, 22' with identical functional effects.

[0047] Although the present invention has been described above based on preferred exemplary embodiments, the present invention is not limited thereto and can be modified in various ways. In particular, the present invention can be variously substituted or modified without departing from the spirit and scope of the present invention.

Claims

1. An implantable temporomandibular joint prosthesis (100), comprising: a first implant part (10) having an artificial condyle (12) attachable to the mandible (30); a second implant part (20, 20') having an articular surface (22, 22') attachable to the skull (40); the articular surfaces (22, 22') form an abutment for the artificial condyle (12); the second implant part (20, 20') comprises a first component (24, 24') made of a metallic material and attachable to the skull (40), and a second component (27, 27') made of plastic and forming the articular surface (22, 22'); the first components (24, 24') have first connecting surfaces (25, 25'), the second components (27, 27') have second connecting surfaces (28, 28'), the first connecting surfaces (25, 25') and the second connecting surfaces (28, 28') interengage with each other and are integrally connected; The first component (24, 24') and the second component (27, 27') form a molten composite (50, 50') on the first connecting surface (25, 25') and the second connecting surface (28, 28').

2. 2. The temporomandibular joint prosthesis according to claim 1, wherein the first connecting surface (25, 25') is provided with a recess (26, 26'), and a protrusion (29, 29') arranged on the second connecting surface (28, 28') engages in the recess (26, 26').

3. 3. The temporomandibular joint prosthesis according to claim 2, wherein the recess (26, 26') in the first connecting surface (25, 25') of the first component (24, 24') and the corresponding protrusion (29, 29') of the second component (27, 27') are of the same or different materials.

4. 4. The temporomandibular joint prosthesis according to claim 2 or 3, wherein the recess (26, 26') in the first connecting surface (25, 25') of the first component (24, 24') has a size between 1 μm and 2000 μm.

5. Temporomandibular joint prosthesis according to any one of claims 1 to 4, wherein the first connecting surface (25, 25') and the second connecting surface (28, 28') are in the form of mutually matching surfaces.

6. Temporomandibular joint prosthesis according to any one of claims 1 to 5, wherein the first connecting surface (25, 25') and the second connecting surface (28, 28') are concave.

7. Temporomandibular joint prosthesis according to any one of claims 1 to 6, wherein the first component (24, 24') is made of titanium or a titanium alloy and the plastic of the second component (27, 27') is made of a thermoplastic material, in particular PE-UHMW as a thermoplastic material.

8. Temporomandibular joint prosthesis according to any one of claims 1 to 7, wherein the first implant part (10) is made of ceramic, PEEK material, metallic material or a combination thereof.

9. Temporomandibular joint prosthesis according to any one of claims 1 to 8, wherein the first component (24, 24') has an edge region (21, 21') that at least locally grips around the second component (27, 27').

10. 10. The temporomandibular joint prosthesis according to any one of claims 1 to 9, wherein the first implant part (10) and the second implant part (20, 20') are removably attachable to the mandible (30) and the skull (40), respectively, by means of a first attachment part (32) and a second attachment part (42, 42').

11. 11. The temporomandibular joint prosthesis of claim 10, wherein the first attachment part (32) has a first arrangement of holes (34) and the second attachment part (42, 42') has a second arrangement of holes (44, 44').

12. A method for manufacturing an implantable temporomandibular joint prosthesis (100), comprising: providing a first implant part (10) having an artificial condyle (12) attachable to a mandible (30); providing a second implant component (20, 20') having an articular surface (22, 22') attachable to the skull (40), the articular surfaces (22, 22') form an abutment for the artificial condyle (12); the second implant part (20, 20') has a first component (24, 24') made of a metallic material and attachable to the skull (40), and a second component (27, 27') made of plastic and forming the articular surface (22, 22'); and b) mutually engaging and integrally connecting the first connecting surface (25, 25') of the first component (24, 24') with the second connecting surface (28, 28') of the second component (27, 27'), wherein the first component (24, 24') and the second component (27, 27') melt together at the first connecting surface (25, 25') and the second connecting surface (28, 28') during connecting to form a molten composite (50, 50').

13. 13. The method of claim 12, wherein heat, pressure, and / or vacuum are applied to the first component (24, 24') and the second component (27, 27') during connection of the first connection surface (25, 25') and the second connection surface (28, 28').

14. 13. The method of claim 12, wherein the molten composite material (50, 50') is formed at the first and second connecting surfaces (25, 25', 28, 28') by inserting the first component (24, 24') into a melt mold (52) and at least partially filling a volume (54) enclosed by the first component (24, 24') in the region of the articulation surfaces (22, 22') with the plastic of the second component (27, 27') in powder form before applying heat, pressure and vacuum.

15. 15. The method of claim 14, wherein the molten mold (52) is multi-part and completely surrounds the first component (24, 24') and the second component (27, 27') during connection of the first component (24, 24') and the second component (27, 27') to one another, forming a molten composite (50, 50').

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