阅读说明：本技术 一种3d打印外层梯度多孔短种植体及其制备方法 (Outer-layer gradient porous short implant for 3D printing and preparation method thereof ) 是由 蒋欣泉 张文杰 吴晓琳 于 2021-01-08 设计创作，主要内容包括：本发明公开了一种3D打印外层梯度多孔短种植体及其制备方法,所述短种植体用于植入患者的牙槽骨种植窝中,包括：头部和与头部的底面连接的体部；体部包括：致密芯体和设于致密芯体外部的多孔层；多孔层具有孔隙；从致密芯体到牙槽骨方向,多孔层的孔隙率逐步增大,其弹性模量由接近或等于致密芯体逐步减小；并且,所述多孔层整体的平均弹性模量与患者的平均骨弹性模量相同。本发明通过3D打印技术一体成型制备；多孔层增加了骨结合面积,有利于短种植体与牙槽骨的结合,有利于短种植体的长期稳定性,即使在牙槽骨高度不足的情况下也能承担较多的负荷。同时,多孔层可以负载药物,诱导骨组织快速长入,应用于上下颌磨牙区骨量不足的缺牙患者。(The invention discloses a 3D printed outer-layer gradient porous short implant and a preparation method thereof, wherein the short implant is used for being implanted into an alveolar bone implantation nest of a patient and comprises: a head and a body connected to a bottom surface of the head; the body includes: the core comprises a dense core body and a porous layer arranged outside the dense core body; the porous layer has pores; the porosity of the porous layer is gradually increased from the compact core to the alveolar bone, and the elastic modulus of the porous layer is gradually reduced from the compact core to the alveolar bone; the average elastic modulus of the porous layer as a whole is the same as the average bone elastic modulus of the patient. The invention is integrally formed and prepared by a 3D printing technology; the porous layer increases the bone bonding area, is beneficial to the bonding of the short implant and the alveolar bone, is beneficial to the long-term stability of the short implant, and can bear more load even under the condition that the alveolar bone is short in height. Meanwhile, the porous layer can be loaded with drugs to induce the bone tissues to grow rapidly, and is applied to edentulous patients with insufficient bone mass in the molar areas of the upper jaw and the lower jaw.)

1. A3D printed outer gradient porous short implant for implantation in an alveolar bone implant socket of a patient, the short implant comprising: a head and a body connected to a bottom surface of the head; the body includes: a dense core and a porous layer disposed outside the dense core;

the porous layer has pores; the porosity of the porous layer is gradually increased from the compact core to the alveolar bone, and the elastic modulus of the porous layer is gradually reduced from the compact core to the compact core; the average elastic modulus of the porous layer as a whole is the same as the average bone elastic modulus of the patient.

2. The 3D printed outer gradient porous short implant according to claim 1, wherein the porosity of the porous layer is 50% to 90%, and the pore size of the pores is 0.5mm to 0.7 mm.

3. The 3D printed outer gradient porous short implant of claim 1, wherein the pores are in communication with each other and internally loaded with a drug to induce rapid bone tissue ingrowth.

4. The 3D printed outer gradient porous short implant according to claim 1, wherein the side wall of the porous layer is provided with external threads in the shape of a saw-tooth that are circumferentially distributed along the body.

5. The 3D printed outer gradient porous short implant of claim 1, wherein the short implant is conical or cylindrical.

6. The 3D printed outer gradient porous short implant of claim 1, wherein the material of the short implant is one of pure titanium, titanium alloy, ceramic, polymer organic material.

7. The 3D printed outer gradient porous short implant of claim 1, wherein the short implant is integrally formed.

8. The method for preparing a 3D printed outer gradient porous short implant according to any one of claims 1 to 7, comprising the steps of:

(1) determining the material of the short implant, then carrying out preoperative jaw quantitative CT shooting on the patient, and calculating the average bone elastic modulus of the patient; (2) designing the porosity of the porous layer of the short implant according to the patient's average bone elastic modulus; (3) and (3) personalized preparation of the short implant by using a 3D printing device.

Technical Field

The invention relates to the technical field of oral implants, in particular to a 3D printed outer-layer gradient porous short implant and a preparation method thereof.

Background

At present, the dental implant restoration is one of the conventional restoration methods for dentition defects and deletions. In the dental implant restoration process, a doctor needs to drill a tooth lacking area of an alveolar bone of a patient, prepare a proper implant nest and implant an implant into the prepared implant nest. However, in clinical work, doctors are limited by insufficient bone amount of alveolar bone or cavity, sinus, neural tube, etc. of patients, and usually need to adopt a bone grafting method to increase the height of bone or implant a short implant. The short implant avoids the risk, time and money cost brought by bone grafting operation, and has obvious advantages compared with the conventional implant for repairing patients with insufficient alveolar bone height. Short implant systems commonly used in China are Branemark system, Nobel speed, bicon, Innova, SybronPro, Neodetn, etc., and have the common feature of short solid design of titanium or titanium alloy and relying on the peripheral threads of the implant to achieve osseointegration with bone tissue. The existing short implants have the following problems: (1) the elastic modulus of the titanium alloy is far higher than that of bone, so that a stress shielding effect is easily generated on the interface of the implant and bone tissue, and the implant is loosened, sunk and even dislocated after long-term use; (2) the implant cannot support the function of the denture for a long time due to short length, small bone combination area and low strength.

The introduction of the porous structure can reduce the overall elastic modulus of the material, the mechanical property is more matched with human skeleton, the three-dimensional communication structure is favorable for the attachment and proliferation of bone cells, the transportation of nutrition and the growth of bone tissues, and the increased bone combination area is favorable for the long-term stability of the implant. The invention patent 'a design and manufacturing method of an individualized 3D printing implant' (application No. 201410691945.2) obtains the average bone elastic modulus of a patient through preoperative jaw quantitative CT shooting, and introduces a porous structure to reduce the elastic modulus of a short implant so as to match the bone elastic modulus of the patient. However, most of the existing porous implants are uniform pore structures, the structures and the mechanical properties of the porous implants are uniform in space, and the elastic modulus of the part of the porous structures close to the compact core body is low, so that the compact core body is not easy to stably support; and the elastic modulus difference of the two sides of the contact interface of the porous structure and the compact core body is large, and the stress concentration phenomenon can be generated.

Disclosure of Invention

The invention aims to improve the existing porous short implant, provides a 3D printed outer-layer gradient porous short implant and a preparation method thereof, is particularly suitable for patients with insufficient bone mass, and remarkably reduces the phenomena of stress shielding and stress concentration while ensuring the overall strength of the short implant.

In order to achieve the above object, the present invention provides a 3D printed outer gradient porous short implant for implantation in an alveolar bone implant socket of a patient, the short implant comprising: a head and a body connected to a bottom surface of the head; the body includes: a dense core and a porous layer disposed outside the dense core; the porous layer has pores; the porosity of the porous layer is gradually increased from the compact core to the alveolar bone, and the elastic modulus of the porous layer is gradually reduced from the compact core to the compact core; the average elastic modulus of the porous layer as a whole is the same as the average bone elastic modulus of the patient.

Optionally, the porosity of the porous layer is 50% -90%, and the pore diameter of the pores is 0.5mm-0.7 mm.

Optionally, the pores are in communication with each other and internally loaded with a drug to induce rapid bone tissue ingrowth.

Optionally, the side wall of the porous layer is provided with external threads, and the external threads are in a sawtooth shape distributed around the body.

Optionally, the short implant is conical or cylindrical.

Optionally, the short implant is made of one of pure titanium, titanium alloy, ceramic and a polymer organic material.

Optionally, the short implant is integrally formed.

The invention also provides a preparation method of the 3D printed outer-layer gradient porous short implant, which comprises the following steps: (1) determining the material of the short implant, then carrying out preoperative jaw quantitative CT shooting on the patient, and calculating the average bone elastic modulus of the patient; (2) designing the porosity of the porous layer of the short implant according to the patient's average bone elastic modulus; (3) and (3) personalized preparation of the short implant by using a 3D printing device.

Compared with the prior art, the invention has the beneficial effects that:

(1) the elastic modulus of the invention is gradually reduced from the compact core body to the alveolar bone and is in gradient continuous change, thereby effectively reducing the occurrence of stress concentration.

(2) The compact core structure of the invention ensures the integral strength of the implant, and the elastic modulus of the part of the porous layer close to the compact core is close to that of the compact core, so that the compact core can be stably supported.

(3) The porous layer can effectively reduce the elastic modulus of the implant, thereby obviously reducing the stress shielding phenomenon.

(4) The invention can change the density, strength, elastic modulus and other properties of the implant by adjusting the parameters of porosity, aperture, thickness and the like of the porous layer so as to meet the use requirements of different parts and alveolar bone conditions in clinic.

(5) The porous layer of the present invention increases the osseointegration area, facilitates the close integration of the implant with the alveolar bone and the long-term stability of the implant, and can bear more load even in the case of insufficient alveolar bone height.

(6) The invention can load various different medicines or factors for promoting bone on different layers of the porous layer to achieve the effect of gradually releasing the medicines, and can utilize the porous structure to load the medicines to induce the bone tissues to grow rapidly.

(7) The invention is integrally prepared by 3D printing, has good flexibility, can realize personalized design, and has simple process and low cost.

Drawings

Fig. 1 is a schematic structural diagram of a 3D printed outer gradient porous short implant of the present invention.

In the figure: 10-head, 11-groove; 20-bulk, 21-dense core, 22-porous layer.

Detailed Description

The technical solution of the present invention is further described below with reference to the accompanying drawings and examples.

Fig. 1 is a schematic structural diagram of a 3D printed outer gradient porous short implant of the present invention. As shown in fig. 1, the short implant for implantation into an alveolar bone implant socket of a patient comprises: a head 10 and a body 20 connected to the bottom surface of the head 10; the head 10 is a transgingival part and the body 20 is a osseointegrated part. The body 20 comprises: a dense core 21 and a porous layer 22 provided outside the dense core 21; porous layer 22 has pores; the porosity of the porous layer 22 increases stepwise from the dense core 21 toward the alveolar bone, and the elastic modulus thereof decreases stepwise from the value close to or equal to that of the dense core 21; the average elastic modulus of the porous layer as a whole is the same as the average bone elastic modulus of the patient. The elastic modulus of the invention is gradually reduced from the compact core body 21 to the alveolar bone and is in gradient continuous change, thereby effectively reducing the occurrence of stress concentration; the compact core body 21 ensures the integral strength of the implant, and the elastic modulus of the part of the porous layer 22 close to the compact core body 21 is close to that of the compact core body 21, so that the compact core body can be stably supported; meanwhile, the porous layer 22 can effectively reduce the elastic modulus of the implant, and significantly reduce the stress shielding phenomenon.

A groove 11 for installing a foundation pile is formed in the 3D printing outer-layer gradient porous short implant, the groove 11 is provided with an internal thread, and the foundation pile is screwed with the short implant through the internal thread. Wherein, the upper part of the foundation pile is connected with the prosthesis to play the roles of supporting, fixing and stabilizing the prosthesis.

The porosity of the porous layer 22 of the present invention is 50% to 90%, and the pore diameter of the pores is 0.5mm to 0.7 mm. To increase the interfacial tightness of the implant with the bone tissue and to reduce the introduction of bacteria, the porosity of the invention starts from 1-2mm from the level of the connection of the head 10 with the body 20. In the embodiment of fig. 1, the pore size of the pores in the porous layer 22 is gradually increased in the direction from the dense core 21 to the alveolar bone to gradually decrease the elastic modulus. The ratio of the thickness of the dense core 21 to the porous layer 22 was 1:1, and the total thickness was 4.8 mm. The porous layer 22 increases the area to be combined with the bone, facilitates the close combination of the implant with the alveolar bone, facilitates the long-term stability of the implant, and can bear more load even if the alveolar bone is short in height.

In some embodiments, the pores in porous layer 22 are interconnected and loaded with active factors (e.g., BMP-2, VEGF, PDGF), elements (strontium, zinc, magnesium, calcium), anti-infective drugs (silver ions, gentamicin), etc. that promote bone tissue growth, inducing rapid bone tissue ingrowth. Preferably, a plurality of different drugs or factors for promoting bones can be loaded in pores with different pore sizes, so that the drugs are gradually and slowly released.

The side wall of the porous layer 22 is provided with external threads, the external threads are in a fine-toothed shape distributed along the body part 20 in a surrounding way, the thread form can be a thread ascending type or a fish fin type, the thread pitch is 0.8mm, and the major diameter of the thread is 6.5 mm. In some embodiments, the present invention may be integrally manufactured by 3D printing and then screwed into the prepared planting nest through the external threads.

The 3D printed outer-layer gradient porous short implant can be designed into various shapes which are commonly used in clinic, including conical shapes, cylindrical shapes, improved conical shapes and the like, and is made of pure titanium, titanium alloy, ceramics and high polymer organic materials, such as PEEK and other oral implant materials which can be used for 3D printing.

The invention also provides a preparation method of the 3D printed outer-layer gradient porous short implant, which comprises the following steps:

(1) the implant material can be determined to be pure titanium, titanium alloy, ceramic, high molecular organic material, such as PEEK and other oral implant materials which can be used for 3D printing.

(2) The method comprises the steps of carrying out jaw bone quantitative CT shooting on a patient before an operation, carrying out three-dimensional reconstruction on CT scanning data of the patient by using computer software according to the CT scanning data, selecting a cross section CT scanning image passing through a midpoint of an edentulous region, designing the position of an implant on the cross section image by using the computer software, and calculating the average bone elastic modulus of the patient according to the bone mass and the bone density of the patient.

(3) Preparing the short implant by using a 3D printing technology: in the preparation process, the 3D printing software needs to divide the design into a plurality of layers, and the design is changed into a real object through the superposition of the layers. Therefore, during the preparation process, porous layer 22 is divided into a plurality of layers with different porosities, and the porosity varies in a gradient manner. The invention can adjust parameters such as porosity, aperture and thickness of each layer according to the average bone elastic modulus of a patient, and design the position and size (such as 4.8mm by 5mm) of the implant so as to achieve the optimal matching effect of the bone elastic modulus.

In conclusion, the 3D printing outer-layer gradient porous short implant ensures the overall strength of the short implant through the compact core body; the elastic modulus of the implant is reduced by the porous layer, thereby remarkably reducing the stress shielding phenomenon. The short implant is prepared by the 3D printing technology, so that the flexibility is good, the personalized design can be realized, the process is simple, and the cost is low.

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be determined from the following claims.