Temporomandibular joint prosthesis

Abstract

The present invention provides a temporomandibular joint prosthesis that can reduce the risk of joint dislocation and improve comfort, and relates to the field of prosthesis technology. The temporomandibular joint prosthesis includes a joint prosthesis and a mandibular ramus prosthesis; the joint prosthesis includes a condylar fossa portion extending to the mandibular ramus and a fixing plate for fixing the condylar fossa portion, the outer side surface of the condylar fossa portion is provided with a groove for hanging the mandibular ramus prosthesis, and the groove forms a condylar fossa; the mandibular ramus prosthesis includes a condylar head rotatably matched with the condylar fossa and a mandibular ramus fixing handle connected to the mandible, the condylar head is fixed to the inner side of one end of the mandibular ramus fixing handle connected to the joint prosthesis, and the condylar head forms a hook structure for hanging the mandibular ramus fixing handle and the condylar fossa; the mandibular ramus fixing handle can be rotatably hung in the condylar fossa through the condylar head. The movement of the prosthesis of the present invention is also more precise and more comfortable.

Description

Technical Field

[0001] The invention relates to the technical field of prostheses, in particular to a temporomandibular joint prosthesis. Background Art

[0002] The mandible is located at the lower part of the maxillofacial region and is the only movable bone in the face. The temporomandibular joint is a joint on the maxillofacial region that can be linked left and right. Under muscle control, the mandible can perform actions such as chewing, swallowing, speaking, and facial expressions. The temporomandibular joint is also one of the most complex joints in the human body. It can support the mandible to rise, fall, advance, retreat, and rotate to meet the needs of chewing and speaking. Such movements are performed more than 3,000 times a day. When tumors, osteolysis, or maxillofacial damage lead to defects in the temporomandibular joint, mandible, and temporal bone, the patient's appearance will change and the corresponding functions will be lost. Temporomandibular joint reconstruction has been an important and effective treatment method in recent years.

[0003] A Chinese patent with application number 202022099965.4 discloses a temporomandibular joint prosthesis, comprising a mandibular prosthesis, a mandibular fixation plate, a glenoid prosthesis made of ultra-high molecular weight polyethylene or ceramic, a glenoid fixation plate, and a condylar prosthesis machined from a cobalt-chromium-molybdenum alloy or made of ceramic, wherein a positioning boss is formed at one end of the mandibular prosthesis that cooperates with the condylar prosthesis, and a positioning groove that cooperates with the positioning boss is formed on the condylar prosthesis. The Chinese patent application number 202022903437.X discloses a total temporomandibular joint prosthesis, comprising a mandibular prosthesis, a condylar head prosthesis, a glenoid base prosthesis and a glenoid socket prosthesis; wherein the head of the mandibular prosthesis is connected to the condylar head prosthesis, the glenoid base prosthesis is connected to the glenoid socket prosthesis, and the bottom surface of the glenoid socket prosthesis is a circular concave surface and fits with the condylar head prosthesis, and the glenoid base prosthesis is provided with a plurality of through screw holes, The mandibular prosthesis includes a head, a neck and a ramus retaining portion, the head is truncated cone-shaped, the ramus retaining portion is semilunar-shaped, and the back side is in contact with the mandibular ramus, a plurality of retaining holes are arranged on the ramus retaining portion, the neck is the connection between the head and the ramus retaining portion, the condylar head prosthesis is a hollow sphere, and the hollow portion in the condylar head prosthesis is truncated cone-shaped to match the head of the mandibular prosthesis, so that the head of the mandibular prosthesis is just connected to the condylar head prosthesis. A Chinese patent application with application number 201510240951.0 discloses an artificial temporomandibular joint replacement prosthesis. The replacement prosthesis includes a condylar fossa prosthesis and a mandibular ramus prosthesis connected to each other. The condylar fossa prosthesis is made of ultra-high molecular weight polyethylene polymer, and includes a tissue surface in contact with the condylar fossa and a functional surface in contact with the mandibular ramus prosthesis. The tissue surface includes a wing plate in contact with and fixed to the zygomatic arch and a protrusion in contact with the condylar fossa. The functional surface includes a recessed portion in contact with the mandibular ramus prosthesis and baffles arranged at both ends of the recessed portion. The mandibular ramus prosthesis includes a condylar head and a mandibular ramus retaining stem. The condylar head is cylindrical and in contact with the recessed portion. The mandibular ramus retaining stem is attached to the outer surface of the mandibular ramus. Chinese patent No. 202321279515.0 discloses a temporomandibular joint prosthesis including a temporal bone connection block, the bottom surface of which is provided with a fossa; a mandibular connection block, the upper end of which is connected to the mandibular condyle, the mandibular condyle extending to the inside of the fossa; and a hydrogel, the hydrogel wraps the fossa and the mandibular condyle to form a joint capsule, the inside of which is injected with sodium hyaluronate. Existing temporomandibular joint reconstruction prostheses, i.e., temporomandibular joint prostheses, all arrange the fossa on the bottom surface of the fossa prosthesis according to the structure of the human temporomandibular joint. The temporomandibular prosthesis is mainly supported by the original muscles and skin tissues connected to the mandible, and the fossa cannot provide support for the mandibular ramus prosthesis.

[0004] The existing design of temporomandibular joint prosthesis is based on the ideal situation that the support and restraint of the mandible by soft tissues are not affected by the lesions. However, in reality, for patients with temporomandibular joint diseases who are treated with temporomandibular joint reconstruction, the mandibular defect and the support and restraint of the mandible by soft tissues such as the body ligament will inevitably be affected, and the support and restraint of the temporomandibular joint prosthesis will be weakened accordingly. Especially in the case of a large part of the overall mandibular defect, the part that needs to be replaced by a metal prosthesis will also increase. The mass of the metal mandibular ramus prosthesis is often greater than the native bone. Without good support from soft tissues such as ligaments, it will cause a large pull on the entire maxillofacial muscle, which not only affects comfort, but also easily leads to the risk of joint dislocation, making it difficult to achieve a more ideal reconstruction effect. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a temporomandibular joint prosthesis which can reduce the risk of joint dislocation and improve comfort.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a temporomandibular joint prosthesis, including a joint prosthesis and a mandibular ramus prosthesis;

[0007] The joint prosthesis comprises a condyle portion extending toward the mandibular ramus and a fixing plate for fixing the condyle portion, the outer side surface of the condyle portion is provided with a groove for hanging the mandibular ramus prosthesis, and the groove forms the condyle portion;

[0008] The mandibular ramus prosthesis comprises a condylar head rotatably matched with the fossa and a mandibular ramus fixing handle used to be connected to the mandible, the condylar head being fixed to the inner side of one end of the mandibular ramus fixing handle connected to the joint prosthesis, and the condylar head forming a hook structure for the mandibular ramus fixing handle to be hooked to the fossa;

[0009] The mandibular ramus fixing handle is rotatably hung in the articular socket through the condylar head.

[0010] Furthermore, the inner surface of the joint socket is an ellipsoidal surface, and the articular surface of the condylar head is a spherical surface that is rotationally matched with the inner surface of the joint socket.

[0011] Furthermore, a ceramic lining is provided on the inner surface of the glenoid cavity.

[0012] Furthermore, the ceramic lining and the glenoid cavity are fused structures.

[0013] Furthermore, the fixing plate includes a zygomatic arch connecting portion that can cover the zygomatic arch, a zygomatic process connecting portion that can cover the zygomatic process of the temporal bone, a petrous connecting portion that can cover the petrous part of the temporal bone, and a squamous connecting portion that can cover the squamous part of the temporal bone.

[0014] Furthermore, a porous structure layer is provided at a portion where the joint socket part contacts the bone surface.

[0015] Furthermore, the unit cell type of the porous structure layer is a diamond unit cell, and the porosity is 60-75%.

[0016] Furthermore, the mandibular ramus fixing handle is provided with an osteotomy surface connecting portion for connecting with the mandibular osteotomy surface, and the osteotomy surface connecting portion adopts a porous structure.

[0017] Furthermore, the unit cell type of the osteotomy surface connection part is a diamond unit cell, the porosity is 60-75%, the porous pore diameter is 0.8-1.1 mm, and the porous rod diameter is 0.3 mm.

[0018] Furthermore, the joint prosthesis and the mandibular ramus prosthesis are made of titanium alloy.

[0019] The beneficial effects of the present invention are as follows: the temporomandibular joint prosthesis of the present invention has a groove arranged on the outer side surface of the fossa portion of the joint prosthesis to form a fossa, and a condyle head rotatably matched with the fossa is arranged on the inner side of one end of the mandibular ramus prosthesis connected to the joint prosthesis, and the mandibular ramus prosthesis is rotatably hung in the fossa by the condyle head, so that the prosthesis can always abut against the fossa and cooperate with the fossa in the lateral direction through the restraining effect of the facial skin soft tissue, and the inner wall of the fossa can not only restrain the movement trajectory of the condyle head, but also provide a certain supporting force for the condyle head, thereby reducing the supporting and pulling force of the muscles on the mandible and the mandibular ramus prosthesis, making the joint not easy to dislocate, and the movement of the prosthesis is more precise and comfortable. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the present invention;

[0021] Figure 2 It is a schematic diagram of the structure of the present invention;

[0022] Figure 3 It is a schematic diagram of the structure of a joint prosthesis;

[0023] Figure 4 yes Figure 3 Rear view of

[0024] Figure 5 It is a schematic diagram of the installation of the temporomandibular joint prosthesis of the present invention;

[0025] As shown in the figure: joint prosthesis 1, mandibular ramus prosthesis 2, fossa part 11, fixation plate 12, mandibular ramus fixation handle 21, condylar head 22, osteotomy surface connection part 23, fossa 111, ceramic lining 112, porous structure layer 113, zygomatic arch connection part 121, zygomatic process connection part 122, squamous part connection part 123, petrous part connection part 124. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0027] like Figure 1 , Figure 2 As shown, the temporomandibular joint prosthesis of the present invention comprises a joint prosthesis 1 and a mandibular ramus prosthesis 2. The joint prosthesis 1 comprises a condylar part 11 extending toward the mandibular ramus and a fixing plate 12 for fixing the condylar part 11. The outer side surface of the condylar part 11 is provided with a groove for hanging the mandibular ramus prosthesis 2, and the groove forms a condylar ramus 111 for the movement of the temporomandibular joint. The mandibular ramus prosthesis 2 comprises a condylar head 22 rotatably matched with the condylar ramus 111 and a mandibular ramus fixing handle 21 connected to the mandible. The condylar head 22 rotatably matches with the condylar ramus 111 to form a temporomandibular joint. The condylar head 22 is fixed to the inner side of one end of the mandibular ramus fixing handle 21 connected to the joint prosthesis 1, and the condylar head 22 forms a hook structure for the mandibular ramus fixing handle 21 to hang and match with the condylar ramus 111. The mandibular ramus prosthesis 2 can be rotatably hung in the condylar ramus 111 through the condylar head 22.

[0028] In the present invention, the fixing plate 12 and the mandibular ramus fixing handle 21 are generally produced and printed according to the matching of each patient; the joint prosthesis 1 and the mandibular ramus prosthesis 2 can be 3D printed with metal and polymer materials. The specific thickness of the joint prosthesis 1 and the mandibular ramus prosthesis 2 is set as required to ensure that no deformation occurs during use. In the embodiment of the present invention, the joint prosthesis 1 and the mandibular ramus prosthesis 2 are both printed with TC4 titanium alloy with a thickness of 2.0 to 3.0 mm. The screw holes for fixing screws can be preset on the fixing plate 12 and the mandibular ramus prosthesis 2 as needed.

[0029] The applicant has found in practice that after installation, the temporomandibular joint prosthesis is not easy to move in the lateral direction (cheek-ear direction) due to the covering and restraint of soft tissues such as facial skin. In the vertical direction, the support and restraint of the mandible by soft tissues such as ligaments of the human body due to the mandibular defect are weakened. As a result, the traditional temporomandibular joint prosthesis with the joint socket set on the bottom of the joint prosthesis has the problem of greater pulling of the maxillofacial muscles, poor prosthesis comfort, and easy joint dislocation. For this reason, if Figure 5As shown, the temporomandibular joint prosthesis of the present invention is provided with a groove on the outer side surface of the condylar fossa portion 11 of the joint prosthesis 1 to form a condylar fossa 111, and a condylar head 22 rotatably matched with the condylar fossa 111 is provided on the inner side of one end of the mandibular ramus prosthesis 2 connected to the joint prosthesis 1, and the mandibular ramus prosthesis 2 is rotatably hung in the condylar fossa 111 by the condylar head 22, so that the prosthesis can always abut against the condylar fossa 111 and cooperate with the condylar fossa in the lateral direction through the restraining effect of the facial soft tissue, and the inner wall of the condylar fossa 111 can not only restrain the movement trajectory of the condylar head 22, but also provide a certain supporting force for the condylar head 22, thereby reducing the support and pulling force of the muscles on the mandible and the mandibular ramus prosthesis, the joint is not easy to dislocate, the movement of the prosthesis is more precise, and the comfort is better. On the other hand, the temporomandibular joint prosthesis of the present invention can better utilize the lateral restraining force of soft tissues such as the facial skin, and can convert it into contact force between the condylar head 22 and the bottom surface of the fossa 111, so that the condylar head 22 abuts against the fossa 111 and cooperates with the fossa and is difficult to slide out, that is, the condylar head 22 will hang in the fossa, so that the muscle support and pulling force on the mandible and the mandibular ramus prosthesis is smaller, and the temporomandibular joint prosthesis is not easy to dislocate.

[0030] In some embodiments, the fossa 111 is a cylindrical groove, and the condylar head 22 is a cylindrical structure. In some embodiments, the fossa 111 is an elliptical cylindrical structure, and the condylar head 22 is a spherical structure. In the embodiment of the present invention, the inner surface of the fossa 111 is an ellipsoidal surface, and the articular surface of the condylar head 22 (the contact surface in contact with the inner surface of the fossa 111) is a spherical surface that rotates with the inner surface of the fossa 111. In this way, the condylar head 22 can rotate in all directions in the fossa 111, and can also move along the inner surface of the fossa 111, so as to better simulate various movements of the real temporomandibular joint. And the above structure is conducive to keeping the condylar head 22 in a conventional position (the center of the fossa), and is also conducive to reducing the support and pulling force of the muscles on the mandible and the mandibular ramus prosthesis, and the comfort of the temporomandibular joint prosthesis is also better. The specific size of the condylar head of the fossa 111 can be fitted according to the corresponding morphology of the original fossa and condylar head of the patient.

[0031] In order to reduce the wear of the joint socket 111, the present invention provides a ceramic lining on the inner surface of the joint socket 111. The ceramic lining can be fixed in the joint socket by a mechanical bonding method, such as screw connection, or by an adhesive method. In the present invention, the ceramic lining and the joint prosthesis 1 are an integrated fusion structure, which can improve the bonding strength of the two and make the prosthesis more durable.

[0032] The specific process of integrated fusion of ceramic lining and joint prosthesis is as follows: first, the joint socket is formed by laser 3D printing, and a porous structure layer is printed on the inner surface of the joint socket, wherein the ceramic lining is formed into a semi-finished product by slurry shaping. After the two are fused, they are heat treated for degreasing, sintering and curing. The heat treatment parameters are: degreasing at 300-320℃ for 2 hours, then heating to 1200-1250℃ for 6 hours, and sintering and curing.

[0033] In order to improve the installation stability of the joint prosthesis 1, in the present invention, the fixing plate 12 includes a zygomatic arch connecting portion 121 that can cover the zygomatic arch, a zygomatic process connecting portion 122 that can cover the zygomatic process of the temporal bone, a petrous connecting portion 124 that can cover the petrous part of the temporal bone, and a squamous connecting portion 123 that can cover the squamous part of the temporal bone. The zygomatic arch connecting portion 121, the zygomatic process connecting portion 122, the petrous connecting portion 124 and the squamous connecting portion 123 can be provided with fixing holes for fixing screws as needed. The fixing plate 12 is not only provided with the zygomatic arch connecting portion 121, but also with the zygomatic process connecting portion 122, the petrous connecting portion 124 and the squamous connecting portion 123. Through the zygomatic arch connecting portion 121, the zygomatic process connecting portion 122, the petrous connecting portion 124 and the squamous connecting portion 123, multiple fixing points can be formed around the articular fossa 111, so that the joint prosthesis 1 is fixed more firmly, and the risk of dislocation of the temporomandibular joint prosthesis is further reduced.

[0034] like Figure 3 , Figure 4 As shown, in the embodiment of the present invention, the joint fossa 11 is provided with a porous structure layer 113 at the part in contact with the bone surface. The porous structure layer 113 can not only stimulate bone growth into the prosthesis, making the fixation of the joint prosthesis 1 more stable, but also reduce the friction noise generated during the movement of the prosthetic joint.

[0035] The porous structure layer 113 may adopt various existing porous structures. In the present invention, preferably, the unit cell type of the porous structure layer 113 is a diamond unit cell, and the porosity is 60-75%.

[0036] In the embodiment of the present invention, the mandibular ramus fixing handle 21 is provided with an osteotomy surface connecting portion 23 for connecting with the mandibular osteotomy surface, and the osteotomy surface connecting portion 23 adopts a porous structure. This can also promote the growth of mandibular bone tissue into the porous inside of the osteotomy surface connecting portion 23, so that the fixation of the mandibular ramus prosthesis 2 is also more stable, and the risk of dislocation of the temporomandibular joint prosthesis is further reduced.

[0037] The osteotomy surface connection part 23 can also adopt various existing porous structures. In the present invention, preferably, the unit cell type of the osteotomy surface connection part 23 is a diamond unit cell, the porosity is 60-75%, the porous pore size is 0.8-1.1 mm, and the porous rod diameter is 0.3 mm.

[0038] The thickness of the osteotomy surface connection portion 23 is set as required. In the present invention, the thickness of the osteotomy surface connection portion 23 is 2.5 to 4.5 mm.

[0039] The temporomandibular joint prosthesis of the present invention can be manufactured by the following method:

[0040] Step 1: Import the patient's head CT data into the medical image processing software, set the "threshold division" value to 220-330, reconstruct the patient's skull model, and design a suitable osteotomy plane according to the patient's temporomandibular tumor boundary or defect, and remove the bone block with the tumor or defect according to the osteotomy plane;

[0041] Step 2: Design the temporomandibular joint prosthesis according to the patient's correction plan. First, reconstruct the mandible according to the patient's facial or bone surface morphology, and use it as the prototype of the mandibular ramus prosthesis. Use 3D design software to design the shape of the mandibular ramus prosthesis connecting handle, and use the smoothing function to make the surface of the mandibular ramus prosthesis smooth and flat. On both sides of the patient, fit the shape of the condylar head and fossa of the mandibular ramus prosthesis according to the shape of the original fossa and articular head. The condylar head of the mandibular ramus prosthesis matches the structure of the joint prosthesis. The overall shape of the joint prosthesis is designed with reference to the shape of the patient's original bone to achieve the effect of precise positioning and good fit.

[0042] Step 3: Export the mandibular ramus prosthesis and joint prosthesis designed in step 2 into STL format files suitable for 3D printing, and print them using metal 3D printing technology. The laser 3D printing of the prosthesis adopts regional process parameter settings, and the laser 3D printing parameters are designed for the support, contour, upper epidermis, lower epidermis and internal area of ​​the parts. The linear energy density of the support is set at 0.15J / mm-0.25J / mm; the linear energy density of the contour is set at 0.1J / mm-0.15J / mm; the volume energy density of the upper epidermis and internal area is set at 55J / mm 3 -70J / mm 3 ; The body energy density of the lower epidermis is set at 50J / mm 3 -60J / mm 3 .

[0043] Example:

[0044] Use a porous or solid structure to wrap the sound source and test the decibel value of the sound in a 50 decibel environment. The test results are shown in Table 1:

[0045] Table 1

[0046] serial number Porous Type Porosity Decibel (dB) Example 1 Diamond unit cell 50％ 34 Example 2 Diamond unit cell 59％ 29 Example 3 Diamond unit cell 68％ 22 Example 4 Diamond unit cell 76％ 34 Example 5 Diamond unit cell 84％ 36 Comparative Example Entity Structure 0 45

[0047] It can be seen from Table 1 that when the cell type of the porous structure is a diamond cell, the noise reduction effect is best when the porosity is 60-75%. Therefore, the present invention uses a diamond cell as the cell type of the porous structure layer 113, and when the porosity is 60-75%, the friction noise generated during the movement of the prosthetic joint can be reduced, and a better effect will be achieved.

[0048] The porous structure unit cell type is diamond unit cell, and the porous structure rod diameter is 0.3 mm. The bone ingrowth limit depth and bone integration period under different pore diameters and porosity conditions are shown in Table 2:

[0049] Table 2

[0050]

[0051]

[0052] As can be seen from Table 2, the larger the porous pore size, the higher the porosity, the greater the depth of bone ingrowth, and the longer the bone integration period; but the bone ingrowth depth is stabilized to about 2mm, and the larger the porous pore size, the longer the bone integration period. Therefore, the unit cell type of the osteotomy surface connecting part 23 of the present invention is a diamond unit cell, the porosity is 60-75%, the porous pore size is 0.8-1.1mm, and the porous rod diameter is 0.3mm, which balances the bone ingrowth depth and the bone integration period, and the biocompatibility of the molded parts with this parameter is better.

Claims

1. A temporomandibular joint prosthesis, comprising a joint prosthesis (1) and a mandibular ramus prosthesis (2), characterized in that: The joint prosthesis (1) comprises a joint socket portion (11) extending toward the mandibular ramus and a fixing plate (12) for fixing the joint socket portion (11); the outer side surface of the joint socket portion (11) is provided with a groove for hanging the mandibular ramus prosthesis (2), and the groove forms the joint socket (111); The mandibular ramus prosthesis (2) comprises a condylar head (22) rotatably matched with the joint fossa (111) and a mandibular ramus fixing handle (21) for connecting to the mandible, wherein the condylar head (22) is fixed to the inner side of one end of the mandibular ramus fixing handle (21) connected to the joint prosthesis (1), and the condylar head (22) forms a hook structure for connecting the mandibular ramus fixing handle (21) to the joint fossa (111); The mandibular ramus fixing handle (21) is rotatably hung in the joint socket (111) via the condylar head (22); A porous structure layer (113) is provided at a portion of the joint socket portion (11) that contacts the bone surface; The unit cell type of the porous structure layer (113) is a diamond unit cell, and the porosity is 60-75%; The mandibular ramus fixing handle (21) is provided with an osteotomy surface connecting portion (23) for connecting to the mandibular osteotomy surface, and the osteotomy surface connecting portion (23) has a porous structure; The unit cell type of the osteotomy surface connection part (23) is a diamond unit cell, the porosity is 60-75%, the porous pore diameter is 0.8-1.1 mm, and the porous rod diameter is 0.3 mm.

2. The temporomandibular joint prosthesis according to claim 1, characterized in that: The inner surface of the joint socket (111) is an ellipsoidal surface, and the joint surface of the condylar head (22) is a spherical surface that is rotationally matched with the inner surface of the joint socket (111).

3. The temporomandibular joint prosthesis according to claim 1, characterized in that: A ceramic lining (112) is provided on the inner surface of the joint socket (111).

4. The temporomandibular joint prosthesis according to claim 3, characterized in that: The ceramic lining (112) and the joint socket (11) are a fused structure.

5. The temporomandibular joint prosthesis according to claim 1, characterized in that: The fixing plate (12) comprises a zygomatic arch connecting portion (121) capable of covering the zygomatic arch, a zygomatic process connecting portion (122) capable of covering the zygomatic process of the temporal bone, a petrous portion connecting portion (124) capable of covering the petrous portion of the temporal bone, and a squamous portion connecting portion (123) capable of covering the squamous portion of the temporal bone.

6. The temporomandibular joint prosthesis according to claim 1, characterized in that: The joint prosthesis (1) and the mandibular ramus prosthesis (2) are both made of titanium alloy.

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