Two-section type high-strength implant and manufacturing method

Abstract

The invention belongs to the field of dental implant, and particularly relates to a two-section type high-strength implant and a manufacturing method, the two-section type high-strength implant comprises an implant and an abutment, the abutment is detachably connected with the implant, the surface of the implant is provided with uniform first-level and second-level holes, the diameter of the first-level hole is 20-100 microns, and the diameter of the second-level hole is 1-10 microns. The implant provided by the invention has excellent mechanical properties and biocompatibility.

Description

Technical Field

[0001] The present invention belongs to the field of dental implants, and in particular relates to a two-stage high-strength implant and a manufacturing method thereof. Background Art

[0002] Dental implants are artificial teeth used to replace natural teeth in cases of edentulous or missing teeth, providing chewing, pronunciation, and aesthetic functions. Commonly used materials are pure titanium or titanium alloys, which offer excellent osseointegration. However, metal materials can have drawbacks such as ion leaching, hypersensitivity, gray lines at the cervical margin, bluish translucency, and bacterial adhesion, making the development of alternative materials imperative.

[0003] Ceramic materials, due to their excellent biocompatibility and aesthetics, have gradually become the new generation of artificial dental implant materials. Over the past decade, ceramic implants have been gradually applied in clinical practice. However, during use, ceramic implants have also been subject to problems such as fracture, infection, and insufficient osseointegration.

[0004] The reasons for the above phenomenon mainly include the following three aspects: 1) There are defects in the external structural design of ceramic implants, which leads to stress concentration in a smaller area. This area is subjected to excessive stress for a long time, resulting in fracture; 2) Defects in the manufacturing process of ceramic implants (including molding, sintering, machining, etc.) make it difficult to meet the requirements for densification and strength of ceramic implants; 3) Ceramic implant surface treatment is difficult. Since ceramic materials are usually hard, surface treatment is difficult. The surface structure, morphology and roughness formed by the surface treatment process are not ideal, and there are fewer bone binding sites, resulting in insufficient bone bonding. Summary of the Invention

[0005] In order to improve the deficiencies of the prior art, the present invention provides a two-stage high-strength implant and a manufacturing method thereof. The implant obtained by the method has excellent mechanical properties and biocompatibility.

[0006] In a first aspect, the present invention provides a two-stage high-strength implant, comprising an implant and a base, wherein the base is detachably connected to the implant, and the surface of the implant has uniform primary and secondary holes, wherein the diameter of the primary holes is 20-100um, and the diameter of the secondary holes is 1-10um.

[0007] According to an embodiment of the present invention, the base is used to extend to the outside of the gums, forming a part that passes through the gums and the oral cavity, and is connected to the restoration. The implant and the base are made by a two-stage molding technology, which has the advantages of good biocompatibility, good aesthetics, and more flexible surgical operation.

[0008] According to an embodiment of the present invention, the implant is connected to the abutment via screws.

[0009] According to an embodiment of the present invention, the interior of the abutment is a hollow structure, and the screw passes through the screw holes inside the abutment and the implant to connect the implant and the abutment together. An anti-rotation groove is provided in the abutment, and the anti-rotation groove is used to connect the crown. The anti-rotation groove makes the crown more anti-rotation, thereby improving the accuracy and convenience of wearing teeth.

[0010] According to an embodiment of the present invention, a blind hole is provided at the top of the implant, and the blind hole has a conical structure. The conical structure is used to seal the blind hole of the implant after being used in conjunction with the abutment to prevent bacteria from entering the blind hole and causing surgical failure.

[0011] According to an embodiment of the present invention, an internal thread is provided in the blind hole for connecting the implant and the base with screws. The internal thread is a smooth structure to prevent stress concentration when the screws connect the implant and the base, which may cause implant failure.

[0012] According to an embodiment of the present invention, a cutting edge is provided at the lower portion of the threaded zone, and the cutting edge is eccentric by 0.1-0.5 mm, preferably, the cutting edge is eccentric by 0.1-0.3 mm.

[0013] According to an embodiment of the present invention, the threaded area includes a base, the threads protrude radially outward from the surface of the base, the diameter of the threaded area gradually decreases from top to bottom, and the bottom diameter of the threaded area is 0.1-0.5 mm smaller than the top diameter.

[0014] According to an embodiment of the present invention, the thread in the threaded area is a multi-thread thread, such as a double-thread or triple-thread thread. The lead of the multi-thread thread (i.e., the distance the thread advances axially per revolution) is a multiple of the single-thread thread with the same pitch, which greatly reduces the time of the implantation operation. For example, the lead of the triple-thread thread is three times the pitch of the single-thread thread, thereby speeding up the implantation speed.

[0015] According to an embodiment of the present invention, the thread surface is a smooth structure.

[0016] In a second aspect, the present invention provides a method for forming the above-mentioned two-stage high-strength implant, comprising the following steps:

[0017] S1. The ceramic powder is loaded into a mold, sealed, and then cold isostatically pressed to obtain a green body;

[0018] S2. The green body is degreased and sintered to obtain a green body;

[0019] S3. The blank is machined to obtain a semi-finished implant;

[0020] S4. Sandblast and acid-etch the semi-finished implant to obtain the implant.

[0021] According to an embodiment of the present invention, the ceramic powder is selected from at least one of alumina powder, zirconia powder, alumina-toughened zirconia powder or zirconia-toughened alumina powder, for example, zirconia powder.

[0022] According to an embodiment of the present invention, the particle size of the zirconium oxide powder is 1 to 100 nm, preferably the particle size of the zirconium oxide powder is 5 to 50 nm, and more preferably, the particle size of the zirconium oxide powder is 10 to 30 nm.

[0023] According to an embodiment of the present invention, the mold is made of an elastic material, such as rubber or plastic.

[0024] According to an embodiment of the present invention, the cold isostatic pressing comprises the following steps: placing a mold filled with ceramic powder into a high-pressure chamber of a cold isostatic press, starting the machine, gradually applying pressure to 250±50 MPa, maintaining the pressure for 5-10 minutes, and compacting the powder under uniform pressure.

[0025] According to an embodiment of the present invention, the steps between step S1 and step S2 include the following steps: depressurizing the high-pressure cavity at a rate of 15±5 MPa / min, demolding, and obtaining a green body.

[0026] According to an embodiment of the present invention, the debinding comprises the following steps: keeping the green body at a temperature of 400° C. to 700° C. for 2 to 4 hours.

[0027] According to an embodiment of the present invention, the sintering comprises the following steps: firstly degreasing the green body, and then keeping the temperature at 1200° C.-1650° C. for 2-6 hours.

[0028] According to an embodiment of the present invention, the debinding comprises the following steps: heating the green body to 700-1200°C at a rate of 50-100°C / h, keeping the temperature for 1-2 hours, and then heating the green body to the sintering temperature at a rate of 100-200°C / h.

[0029] According to an embodiment of the present invention, after sintering in step S2, the following steps are further included: cooling the sintered green body to below 450°C±100°C at 100°C±20°C / h, and then naturally cooling to room temperature to obtain a green body.

[0030] According to an embodiment of the present invention, the machining includes rough machining and fine machining, wherein the rough machining adopts a common alloy end mill with a tool diameter of 5-10 mm, and the fine machining adopts a special alloy end mill with a diameter of 1-10 mm.

[0031] According to an embodiment of the present invention, the machined implant semi-finished product is first sandblasted.

[0032] According to an embodiment of the present invention, the sandblasting process includes spraying sand balls onto the surface of the implant semi-finished product. Preferably, the sand balls are selected from boron carbide, zirconium oxide or aluminum oxide, preferably zirconium oxide, more preferably aluminum oxide. Preferably, the diameter of the sand balls is 50-500 μm, preferably 80-400 μm, more preferably 100-200 μm. Furthermore, the pressure of the sandblasting is 1-10 bar, for example, 2-5 bar; the working distance of the sandblasting is 10-50 mm, for example, 15 mm, preferably 8-10 mm; the moving speed of the sandblasting is 1-20 mm / s, for example, 5 mm / s.

[0033] According to an embodiment of the present invention, the etching process includes: etching the surface of the sandblasted semi-finished implant product using an etching solution.

[0034] According to an embodiment of the present invention, the etching solution includes a first acid and hydrofluoric acid. Preferably, the first acid can be selected from at least one, two or more of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, etc. Further, the hydrofluoric acid is selected from 30-50vol% hydrofluoric acid; the first acid is selected from 50-80vol% nitric acid or 30-50vol% sulfuric acid, 40-60vol% phosphoric acid. More preferably, the etching solution is obtained by mixing 30-50vol% hydrofluoric acid with 50-80vol% nitric acid, preferably 35-45vol% hydrofluoric acid with 60-70vol% nitric acid. Exemplarily, the etching solution includes hydrofluoric acid (40vol%) and nitric acid (50vol%), and the volume ratio of the two is 4:6.

[0035] According to an embodiment of the present invention, in the etching solution, the volume ratio of the hydrofluoric acid to the first acid is (2-8):(8-2), preferably (4-6):(6-4), and more preferably 4:6.

[0036] According to an embodiment of the present invention, the etching time is 1 min-120 min, preferably 20-40 min, and more preferably 30 min.

[0037] According to an embodiment of the present invention, the etching temperature is 30-100°C, for example, 70°C or 80°C.

[0038] Beneficial effects

[0039] 1) The two-stage high-strength implant in the present invention has a blind hole at the top of the implant, which has a conical structure and an internal thread inside the blind hole. The conical structure is used to seal the blind hole of the implant after being used in conjunction with the abutment to prevent bacteria from entering the blind hole and causing surgical failure; the internal thread is a threaded structure, which can prevent stress concentration when the screw connects the implant and the abutment, causing implant failure; the split implant is composed of the implant body and the abutment separately. During surgery, the doctor can flexibly select implant bodies of different sizes and designs for implantation according to the specific conditions of the patient's alveolar bone, such as bone amount, bone density, alveolar bone height and width, etc.; after the implant body of the split implant is implanted, it heals for a period of time to form a stable bone bond before the abutment is installed, reducing the risk of bone bond being affected by external interference during the healing process of the implant.

[0040] 2) The two-stage high-strength implant in the present invention has a threaded area at the bottom of the implant, the diameter of the threaded area gradually decreases from top to bottom, and the thread in the threaded area is a multi-thread thread. The multi-thread thread not only has a larger lead but also a larger surface area, which can speed up the implantation speed, provide more attachment sites, and improve the stability of the implant.

[0041] 3) The two-stage high-strength implant of the present invention has smooth threads in the threaded area, which can avoid stress concentration, achieve the effect of dispersing force, reduce the occurrence of mechanical complications of the implant, and improve the success rate of the operation.

[0042] 4) The material of the present invention is zirconia ceramic material, and zirconia powder with a particle size of 5-50 nanometers is selected and formed under specific temperature, pressure and other conditions. The obtained zirconia implant embryo has a monoclinic phase content of less than 2% before aging and less than 3% after aging; the four-point bending strength before aging is greater than 2000MPa, the four-point bending strength after aging is greater than 1800MPa, and the fracture toughness is greater than 10MPa·m 1 / 2 , Young's modulus is greater than 210GPa, and hardness is greater than 12GPa. Therefore, the implant has high strength and long service life. Zirconia ceramics have good light transmittance and color stability, which can meet patients' needs for aesthetics.

[0043] 6) The inventors unexpectedly discovered that under specific conditions, sandblasting followed by acid etching treatment can produce uniform primary and secondary pores on the surface of the implant, with the primary pores having a diameter of 20-100 μm and the secondary pores having a diameter of 1-10 μm. The formation of the primary and secondary pores allows osteoblasts to grow in the cavities, greatly improving the stability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Schematic diagram of the implant structure;

[0045] Figure 2This is a cross-sectional view of the implant, abutment, and screw after assembly;

[0046] Figure 3 This is a schematic diagram of the surface area measurement of the threaded portion of a single-threaded product;

[0047] Figure 4 This is a schematic diagram of the surface area measurement of the threaded portion of a double-threaded product;

[0048] Figure 5 This is a static compression diagram of the YY / T 0521-2018 product;

[0049] Figure 6 This is a schematic diagram of the finite element analysis results for the unsmooth design of the thread;

[0050] Figure 7 This is a schematic diagram of the finite element analysis results for the smooth design of the thread;

[0051] Figure 8 Implant fabrication process flow chart;

[0052] Figure 9 This is a ×100 electron microscope view of a ceramic implant after sandblasting and acid etching;

[0053] Figure 10 This is a ×500 electron microscope view of a ceramic implant after sandblasting and acid etching;

[0054] Figure 11 This is a ×2000 electron microscope view of a ceramic implant after sandblasting and acid etching;

[0055] Figure 12 This is a ×5000 view of the ceramic implant after sandblasting and acid etching under an electron microscope.

[0056] In the figure, 1-implant, 2-blind hole, 3-cutting edge, 4-soft tissue connection area, 5-threaded area, 6-abutment, 7-screw. DETAILED DESCRIPTION

[0057] The structure of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely exemplary illustrations and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are encompassed within the scope of protection intended by the present invention.

[0058] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0059] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0060] Example 1 Structure of a two-stage high-strength implant

[0061] See also Figure 1 , Figure 2 As shown, the two-stage high-strength implant includes an implant 1 and a base 6. The base 6 is detachably connected to the end of the implant 1. In this embodiment, the implant 1 and the base 6 are connected by a screw 7. The base 6 is used to extend to the outside of the gum to form a transgingival part and be connected to the restoration.

[0062] A blind hole is provided on the upper part of the implant 1, and the blind hole has a conical structure. The conical structure is used to seal the blind hole of the implant 1 after being used in conjunction with a cover screw or a base to prevent bacteria from entering the blind hole and causing surgical failure.

[0063] An internal thread is provided in the blind hole for connecting the implant 1 and the base 6 with a screw 7. The internal thread is a smooth structure to prevent stress concentration when the screw connects the implant and the base, which may cause implant failure.

[0064] The base 6 has a soft tissue connection area 4, which is located at the lower part of the base 6. When the implant 1 and the base 6 are implanted, the soft tissue connection area 4 corresponds to the soft tissue. The soft tissue connection area 4 is an arc-shaped structure with an arc angle of R1-R5. The soft tissue connection area 4 can provide an attachment platform for the soft tissue, and the arc structure can fit and cover the surface of the soft tissue to form a seamless structure, preventing bacteria from entering the alveolar bone from the gap between the soft tissue connection area 4 and the soft tissue, causing inflammation, and thus leading to implant failure.

[0065] The implant 1 has a threaded area 5, and a cutting edge 3 is provided at the lower part of the threaded area 5. The height of the cutting edge 3 is 5-10 mm, and the cutting edge 3 is eccentric by 0.1-0.5 mm. The purpose of providing the cutting edge 3 is to make it easier for the operator of the implant 1 to implant the product. As we all know, M=F×L. When the torque M is constant, the smaller L and the larger F are, the greater the cutting force generated, so the more effort is saved; the bottom end of the implant 1 is round, which can prevent perforation of the maxillary sinus and make the product safer.

[0066] The threaded area 5 includes a base, and the threads protrude radially outward from the surface of the base. The diameter of the threaded area 5 gradually decreases from top to bottom, and the bottom diameter of the threaded area 5 is 0.1-0.5mm smaller than the top diameter. The larger the diameter of the threaded area 5, the greater the shear force that the implant 1 can withstand, and the larger the contact area with the alveolar bone, the better the stability of the product. This design increases the mechanical stability of the product.

[0067] The threaded area 5 gradually decreases in diameter from top to bottom (hereinafter referred to as the tapered thread) has the following advantages:

[0068] 1. Initial stability

[0069] 1. During implantation, the thread diameter of a dental implant with a graduated thread gradually decreases from top to bottom. This structure allows for closer contact between the implant and the surrounding bone tissue. For example, initially, the coarser threads contact the cortical bone. As implant depth increases, the threads gradually taper, better fitting the cancellous bone. This close fit, like a specially designed key fitting into a corresponding lock, increases friction between the implant and bone tissue, effectively improving the initial stability of the implant.

[0070] 2. Compared with traditional equidistant and coarse threads, gradient threads can adaptively fit according to different bone conditions (such as areas with different bone density). They can also better grasp bone tissue in areas with lower bone density, reduce micro-movement of the implant after implantation, and create good conditions for subsequent bone integration.

[0071] 3. The gradual thread can better disperse the stress on the implant under functional load to the surrounding bone tissue. When the patient chews food and generates biting force, the implant is subjected to axial and lateral forces. The gradual thread structure can make the stress more evenly distributed to the bone tissue along the gradual direction of the thread.

[0072] 2. Osseointegration

[0073] 1. The gradual thread structure is similar to building a "growth track" for bone cells, which is conducive to the deposition and growth of new bone on the implant surface. Compared with traditional threads, the gradual thread can promote the contact and integration of bone tissue and implants in the early stage after implantation, shortening the time of bone integration.

[0074] 2. Increase the bone integration area: Due to the shape characteristics of the gradual thread, it can provide a larger bone integration area under the same implant size. As the thread gradually changes, the contact area between the implant surface and the bone tissue is increased in three-dimensional space. For example, in the process of the thread changing from coarse to fine, the contact method between each circle of thread and the bone tissue is different. On the whole, more bone tissue can interact with the implant surface, which is like building a wider "connection bridge" between the implant and the bone tissue, thereby improving the quality and strength of bone integration, which is conducive to the long-term and stable existence of the implant in the jawbone.

[0075] 3. Aesthetic Effect

[0076] 1. Gum morphology maintenance: Gradual thread implants provide good support for gingival tissue. After implant restoration, the appropriate implant structure helps maintain the natural morphology of the gums. Due to its good initial stability and bone integration properties, the bone tissue around the implant can remain stable, thereby providing stable support for the gums. For example, in single-tooth implant restoration, gradual thread implants can avoid gingival recession caused by implant loosening or bone absorption, making the contour of the gingival edge more natural and beautiful, meeting the requirements of aesthetic restoration.

[0077] 2. Reduce soft tissue complications: Gradual thread implants are beneficial to the health of the soft tissues around the implants. Gradual threads enable the implants to better adapt to the physiological environment in the oral cavity and reduce stimulation to the surrounding soft tissues because they can maintain a stable position during implantation and functional loading, and will not cause damage to soft tissues such as the gums due to micro-movements.

[0078] 3. Compared with non-gradient thread implants, gradient thread implants can reduce the incidence of soft tissue complications such as peri-implantitis, which is beneficial to maintaining the aesthetics and health of oral soft tissue after implant restoration.

[0079] The thread of the threaded zone 5 is a multi-thread thread, such as a double-thread or triple-thread thread. The lead of the multi-thread thread (i.e., the distance the thread advances axially per revolution) is a multiple of the single-thread thread with the same pitch, which greatly reduces the time of the implantation operation. For example, the lead of the triple-thread thread is three times the pitch of the single-thread thread, thereby speeding up the implantation speed.

[0080] The multi-thread design can increase thread density and surface area while maintaining a faster implant speed. Figure 3 and Figure 4 As shown, The surface area of ​​the threaded portion of the single-start thread and Schematic diagram of the measurement of the surface area of ​​the threaded part of the double-thread structure, where the surface area of ​​the threaded part of the single-thread structure is 191.73 square millimeters, and the surface area of ​​the threaded part of the double-thread structure is 193.7 square millimeters). It can be seen that the multi-thread structure has a larger surface area and can provide more attachment sites, which enables the implant 1 to obtain better stability in the early stage. This design helps to reduce the vibration and displacement of the implant 1 after implantation, thereby improving the long-term success rate of the implant 1.

[0081] Furthermore, the thread structure is an important structure for maintaining the bone mass in the neck. When the implant 1 performs its function, the force transmitted to the bone-implant interface by the implant 1 with a smooth neck design is mainly shear force. Shear force is the force that causes the greatest damage to bone tissue. Compared with shear force, bone tissue has a higher tolerance to pressure and tension. The design of the multi-thread thread in the present invention changes the type of force at the bone-implant interface, increases the tolerance of the bone tissue around the implant, and thus effectively reduces bone absorption in the implant neck.

[0082] The neck is a threaded structure, which enables the implant to better adapt to the physiological functions of the surrounding bones and preserve the surrounding bones. The large thread at the bottom of the implant mainly increases mechanical stability in the early stage and increases bone integration stability in the later stage. The thread at the neck does not play a role in increasing initial stability in the early stage of implantation, but reduces stress concentration in the neck. Its later role is to reduce stress concentration during occlusion and convert shear force into tensile stress or compressive stress, reduce bone absorption, and promote bone integration.

[0083] When the implant is made of zirconia, the failure of the implant 1 made of zirconia is usually due to stress concentration, which causes stress concentration points to break and then extend to the line, and then causes the entire implant 1 to break. To solve this problem, the present invention uses arc threads, and the arc threads are designed to be smooth R0.1-R0.5mm to avoid stress concentration and achieve the effect of dispersing force, greatly improving the success rate of the operation. The tooth angle of the arc thread is 50~70°, and the thread height is 0.2~0.5mm.

[0084] According to the product embedding method and mechanical loading method of regulation YY / T 0521-2018, the rounded implant and the unrounded implant in this embodiment were analyzed by applying a static pressure of 200N at the same time (the other structures of the two implants were the same, and three parallel tests were performed on each implant). Figure 5 The figure shows the static compression diagram of the product in accordance with Regulation YY / T 0521-2018.

[0085] See also Figure 6 and Figure 7As shown in Figure 1 (wherein, the thread is calculated three times and the three average values ​​are taken), the implants corresponding to smooth and unsmooth threads are analyzed and statistically analyzed by three finite element methods. As shown in Tables 1 and 2, the average maximum stress of the product with unsmooth thread design is 1043 MPa, and the average maximum stress of the product with smooth thread design is 561.7 MPa. It can be seen that the local stress of the implant 1 with smooth thread design is smaller than that of the product with unsmooth thread design, that is, the smooth thread design of the product can effectively disperse stress and avoid stress concentration.

[0086] Table 1 Finite element analysis results of implants with unsmooth threads

[0087]

[0088] Table 2 Finite element analysis results of implants with smooth threads

[0089] Group Maximum stress 1 561.8Mpa 2 561.2Mpa 3 562.1Mpa average value 561.7Mpa

[0090] Example 2: Forming method of two-stage high-strength implant

[0091] The raw material in this embodiment is zirconium oxide powder. The selection of zirconium oxide powder directly affects the mechanical properties of the manufactured implant. The inventor unexpectedly discovered that when the particle size of the zirconium oxide powder is 5-50 nanometers, the mechanical properties of the manufactured implant are the best.

[0092] See also Figure 8 As shown, the molding method of zirconium oxide powder includes the following steps:

[0093] 1. Powder filling and cold isostatic pressing:

[0094] Zirconia powder is placed in an elastic mold, sealed and placed in a high-pressure container. A high-pressure pump is used to make the liquid medium generate uniform static pressure on the mold. The powder is compacted under isotropic pressure to form a green body with a certain density and strength.

[0095] 1) Mold preparation:

[0096] The elastic mold is designed and made according to the shape and size of the implant, usually using materials such as rubber or plastic to ensure that the mold has good flexibility and sealing.

[0097] 2) Compaction:

[0098] Put an appropriate amount of zirconium oxide powder into the mold, place it in the high-pressure chamber of the cold isostatic press, start the machine, gradually apply pressure to about 250±50MPa, maintain the pressure for 5-10 minutes, and compact the powder under uniform pressure.

[0099] 3) Demolding treatment:

[0100] After the pressing is completed, the pressure is slowly released until the pressure is reduced to 0 MPa before the mold is removed. The pressure release rate is 15±5 MPa / min. The mold is removed and demolded to obtain a zirconia green body.

[0101] 2. Sintering:

[0102] 1) Degreasing treatment:

[0103] Before sintering, the zirconia green body needs to be degreased to remove organic matter and impurities in the body, such as binders. The degreasing treatment is usually carried out at a temperature of 400℃-700℃ for a period of time. The holding time depends on the size and shape of the body, and is generally 2-4 hours.

[0104] 2) Heating stage:

[0105] After debinding is completed, the debinded green body is heated. The heating rate should not be too fast to avoid cracks or deformation of the green body due to thermal stress. Generally, multi-stage heating is adopted, such as first heating to 700℃-1200℃ at a rate of 50-100℃ / h, keeping it warm for 1-2 hours, and then heating to sintering temperature at a rate of 100-200℃ / h.

[0106] 3) Sintering stage:

[0107] The sintering temperature is usually between 1200℃ and 1650℃, and the holding time is 2-6 hours. During this stage, the particles in the green body undergo material migration, the pores are eliminated, and the green body gradually densifies.

[0108] 4) Cooling stage:

[0109] After sintering is completed, the temperature is lowered to below 450°C ± 100°C at a rate of 100°C ± 20°C / h, and then naturally cooled to room temperature to obtain the implant body.

[0110] The mechanical and various index tests of the implant embryos made using the molding process of the present invention are shown in the table below. The data show that the implant embryos made using the molding process of the present invention have significant improvements in various indexes.

[0111] As shown in Table 3, static pressing and sintering were performed according to the above steps to obtain an implant body.

[0112] Table 3 Molding conditions of zirconia powder in different embodiments

[0113]

[0114] Table 4 Various indicators of the implant embryo prepared in Example 4

[0115]

[0116] Example 7 Machining and surface treatment

[0117] The implant blanks obtained in Examples 3-6 were machined to obtain the structure in Example 1. The machining was carried out by using different tool steps, wherein a common alloy end mill was used for rough machining, and the tool diameter was selected to be 5-10 mm, and a special alloy end mill was used for fine machining, and the diameter was selected to be 1-10 mm.

[0118] Surface treatment process

[0119] Sandblasting and acid etching of ceramic implants is a surface treatment technique used to improve the bonding between the implant and the surrounding bone.

[0120] Sandblasting involves impinging particles of a specific diameter onto the implant surface at high speed, creating a defined roughness. This roughened surface increases the implant's surface area, providing more space for new bone formation and promoting osseointegration. Furthermore, appropriate roughness promotes osteoblast adhesion, proliferation, division, differentiation, extracellular matrix secretion, and bone formation.

[0121] Acid etching treatment involves exposing the implant to a certain concentration of acid to undergo a chemical reaction. Tiny holes will form on the surface of the semi-finished implant. These holes can promote the attachment of the pseudopodia of osteoblasts, which is beneficial to the attachment and growth of bone cells.

[0122] The present invention performs sandblasting and then acid etching on the machined semi-finished implant product. After sandblasting and acid etching, uniform primary and secondary holes can be formed on the product surface. The primary holes are 20-100um, and the secondary holes are 1-10um. The formed primary and secondary holes allow osteoblasts to grow in the holes, thereby greatly improving the stability of the product.

[0123] Specifically, the machined semi-finished implant is first sandblasted. The sandblasting process includes spraying sand balls onto the surface of the semi-finished implant. The sand balls are selected from boron carbide, zirconium oxide or aluminum oxide, preferably zirconium oxide, and more preferably aluminum oxide. Preferably, the diameter of the sand balls is 50-500 μm, preferably 80-400 μm, and more preferably 100-200 μm. Furthermore, the pressure of the sandblasting is 1-10 bar, for example, 2-5 bar; the working distance of the sandblasting is 10-50 mm, for example, 15 mm, and preferably 8-10 mm; the moving speed of the sandblasting is 1-20 mm / s, for example, 5 mm / s.

[0124] The etching treatment includes: using an etching liquid to treat the surface of the sandblasted implant semi-finished product.

[0125] The etching solution includes a first acid and hydrofluoric acid. The first acid can be selected from at least one, two or more of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, etc. Further, the hydrofluoric acid is selected from 30-50vol% hydrofluoric acid; the first acid is selected from 50-80vol% nitric acid or 30-50vol% sulfuric acid, 40-60vol% phosphoric acid. More preferably, the etching solution is obtained by mixing 30-50vol% hydrofluoric acid and 50-80vol% nitric acid, preferably 35-45vol% hydrofluoric acid and 60-70vol% nitric acid. Exemplarily, the etching solution includes hydrofluoric acid (40vol%) and nitric acid (50vol%), and the volume ratio of the two is 4:6.

[0126] In the etching solution, the volume ratio of the hydrofluoric acid to the first acid is (2-8):(8-2), preferably (4-6):(6-4), and more preferably 4:6.

[0127] The etching time is 1 min to 120 min, preferably 20 to 40 min, and more preferably 30 min.

[0128] The etching temperature is 30-100°C, for example, 70°C or 80°C.

[0129] Table 5 Sandblasting and acid etching conditions of different green bodies

[0130]

[0131] Because the implant products prepared in this invention are Class III medical devices, strict requirements are imposed on the product's cleaning and packaging environment, as well as the initial bacterial contamination and particulate count of the product after cleaning and packaging. The cleaning and packaging environment should be no less than Class 100,000, and the initial bacterial contamination of the product after cleaning and packaging should be ≤100 cfu / g. The cleaning parameters are a temperature of 40-80°C and a cleaning time of 20-60 minutes.

[0132] There are three sterilization methods for medical devices: irradiation, ethylene oxide, and autoclave. Irradiation sterilization is not recommended for ceramic materials because it changes color and degrades mechanical properties. High-pressure steam sterilization is complex and affects the shelf life of the material, so it is also not recommended. Ethylene oxide sterilization does not affect product performance and is more convenient for batch operation, so it is used. Sterilized products must undergo testing upon return to the factory, including product sterility, bacterial endotoxin ≤ 0.25 EU / mL, and ethylene oxide residual ≤ 10 μg / g.

[0133] The above examples illustrate the specific embodiments of the present invention. However, the scope of protection of the present invention is not limited to the above-mentioned exemplary embodiments. Any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art within the spirit and principles of the present invention shall be included in the scope of protection of the claims of the present invention.

Claims

1. A two-stage high-strength implant, characterized in that: It comprises an implant and a base, wherein the base is detachably connected to the implant, and the surface of the implant has uniform primary and secondary holes, wherein the diameter of the primary holes is 20-100um, and the diameter of the secondary holes is 1-10um.

2. The two-stage high-strength implant according to claim 1, characterized in that: The interior of the base is a hollow structure, and an anti-rotation groove is arranged in the base. The anti-rotation groove is used to connect the crown, and the anti-rotation groove makes the crown more anti-rotation. Preferably, a blind hole is arranged at the top of the implant, and the blind hole has a conical structure, and the conical structure is used to close the blind hole of the implant after being used in conjunction with a cover screw or a base. Preferably, the blind hole is provided with an internal thread for connecting the implant and the base with screws, and the internal thread is a smooth structure to prevent stress concentration when the screws connect the implant and the base, thereby preventing implant failure.

3. The two-stage high-strength implant according to claim 1, characterized in that: The implant is provided with a threaded area, a cutting edge is provided at the lower part of the threaded area, and the cutting edge is eccentric by 0.1-0.5 mm. Preferably, the threaded area includes a base, the threads protrude radially outward from the surface of the base, the diameter of the threaded area gradually decreases from top to bottom, and the bottom diameter of the threaded area is 0.1-0.5 mm smaller than the top diameter. Preferably, the thread of the threaded zone is a multi-thread thread. Preferably, the thread surface is a smooth structure.

4. A method for forming a two-stage high-strength implant according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: S1. The ceramic powder is loaded into a mold, sealed and cold isostatically pressed to obtain a green body; S2. The green body is degreased and sintered to obtain a green body; S3. Machining the blank to obtain a semi-finished implant; S4. Sandblast and acid-etch the semi-finished implant to obtain the implant.

5. The molding method according to claim 4, characterized in that: The ceramic powder is selected from at least one of alumina powder, zirconia powder, zirconia toughened alumina powder or alumina toughened zirconia powder, for example, zirconia powder. Preferably, the particle size of the zirconium oxide powder is 1 to 100 nm. Preferably, the cold isostatic pressing comprises the following steps: placing a mold filled with ceramic powder into a high-pressure chamber of a cold isostatic press, starting the machine, gradually applying pressure to 250±50 MPa, maintaining the pressure for 5-10 minutes, and compacting the powder under uniform pressure.

6. The molding method according to claim 4, characterized in that: The steps between step S1 and step S2 include the following steps: depressurizing the high-pressure cavity at a rate of 15±5 MPa / min, demolding, and obtaining a green body. Preferably, the degreasing comprises the following steps: keeping the green body at a temperature of 400° C.-700° C. for 2-4 hours. According to an embodiment of the present invention, the sintering comprises the following steps: firstly degreasing the green body, and then keeping the temperature at 1200° C.-1650° C. for 2-6 hours. Preferably, the debinding comprises the following steps: heating the green body to 700°C-1200°C at a rate of 50-100°C / h, keeping the temperature for 1-2 hours, and then heating to the sintering temperature at a rate of 100-200°C / h.

7. The molding method according to any one of claims 4 to 6, characterized in that: The steps between step S2 and step S3 include the following steps: cooling the sintered body to below 450°C±100°C at 100°C±20°C / h, and then naturally cooling to room temperature to obtain an implant body.

8. The molding method according to any one of claims 4 to 6, characterized in that: The machined implant semi-finished product is firstly subjected to sandblasting treatment. Preferably, the sandblasting process comprises spraying sand balls onto the surface of the implant semi-finished product, the sand balls are selected from boron carbide, zirconium oxide or aluminum oxide, and the diameter of the sand balls is 50-500 μm. Preferably, the pressure of the sandblasting is 1-10 bar, the working distance of the sandblasting is 10-50 mm, and the moving speed of the sandblasting is 1-20 mm / s.

9. The molding method according to claim 8, characterized in that: The etching treatment includes: using an etching liquid to treat the surface of the implant semi-finished product after sandblasting, removing easily removable substances in the blank, and forming a hole structure on its outer surface. Preferably, the etching solution comprises a first acid and hydrofluoric acid, and the first acid is selected from at least one, two or more of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid and the like.

10. The molding method according to claim 9, characterized in that: In the etching solution, the volume ratio of the hydrofluoric acid to the first acid is (2-8): (8-2). Preferably, the etching time is 1 min-120 min, and the etching temperature is 30-100°C.

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