CN116439862A - Zirconia ceramic implant with three-dimensional communicated hierarchical pore structure and preparation method thereof - Google Patents

Abstract

The invention relates to a zirconia ceramic implant with a three-dimensional communicated hierarchical pore structure and a preparation method thereof. The beneficial effects of the invention are as follows: the implant body surface is distributed with the design that bone-combining holes are communicated with the multi-stage hole structure inside, the multi-stage hole structure promotes the migration and infiltration of cells related to bone repair inwards along the pore canal, has good osteogenesis inducing effect, promotes the human tissue to be combined with the implant device better in a short time, enables the human tissue to generate certain tensioning effect on the implant, improves the stability, ensures higher mechanical property while ensuring higher porosity required by the human tissue, and is beneficial to the rapid recovery of oral functions.

Description

Zirconia ceramic implant with three-dimensional communicated hierarchical pore structure and preparation method thereof

Technical Field

The invention belongs to the technical field of medical oral appliances, and particularly relates to a zirconia ceramic implant with a three-dimensional communicated hierarchical pore structure and a preparation method thereof.

Background

The zirconia ceramic material has beautiful color, the color is close to that of natural teeth, no cytotoxicity effect is caused, and the zirconia ceramic material has the advantages of good cell adhesion, less inflammatory infiltration, good biocompatibility with surrounding tissues and the like, so that the zirconia ceramic material can be applied to implant materials, and can well solve the problems of discoloration, corrosion, allergy and the like caused by metal. However, the bioinertness of zirconia ceramics limits their use as implant materials in the biomedical field. The combination rate of the biological inert surface and the bone tissue around the implantation is low, and the related actions such as cell adhesion, proliferation and differentiation cannot be regulated, so that the osseointegration is poor, which is the main reason for the failure of in vivo implantation. Secondly, the elastic modulus of the zirconia is 200GPa, which is more than ten times larger than the 7-20 GPa of the bone modulus of a person, and the stress shielding effect is easy to generate when the zirconia implant is implanted into the oral cavity, so that the stability of the zirconia implant after being implanted into the oral cavity is poor. Patent CN115475024a discloses a zirconia implant with gradual biological activity and a preparation method, and the zirconia implant with better biological activity is prepared by adopting a mode of matching zirconia ceramic ink with hydroxyapatite ceramic ink through material jet printing. Although the biological activity and the bone-combining effect of zirconia are improved to a certain extent, the implant is solid and only adopts the traditional thread combination, and as the service time is increased, stress concentration is easy to occur when the implant is subjected to masticatory force, so that the phenomenon of tooth collapse or loosening and falling off can occur, and the stability is slightly poor.

To solve the above problems, there are two main methods:

firstly, the surface of the implant is activated, so that the bioactivity and the osteogenesis capacity of the implant are improved, and the stability of the implant in the initial stage of implantation is improved; the implant surface treatment method as disclosed in patent CN115581531a, the surface roughening treatment improves the bioactivity by adopting shot blasting treatment and acid etching to form two-stage holes on the surface of the implant; the surface coating method of the zirconia ceramic implant material and the application thereof disclosed in the patent CN113636868A form a functional gradient coating of a three-layer composite oxide film on the zirconia surface by utilizing an atomic layer deposition technology, thereby improving the bioactivity function of the zirconia ceramic implant material. However, the coarsening difficulty of the zirconia surface is high, the working efficiency is low, and the pore structure, size, distribution and depth formed by shot blasting are difficult to accurately control; for zirconia ceramics, the coating method has low bonding strength of a matrix and the coating, low stability, possibility of stripping after long-term service, and incapability of preparing uniform coatings under the condition of complex surface structures of samples, thereby limiting clinical application of zirconia implants.

Secondly, the structure of the implant material is optimally designed to be a porous material with a pore structure, so that the implant material has the capability of inducing tissue regeneration while the elastic modulus is reduced. As disclosed in patent publication No. CN114010349a, a dental implant with 3D printed porous surface zirconia and a design and processing method thereof, a composite structure implant with compact core and 25-45% surface porosity is prepared by adopting a three-dimensional light curing and digital light processing mode, and has better osteogenesis induction capability, but the strength is obviously reduced due to the introduction of holes at the surface part, and the dental implant is extremely easy to damage.

Therefore, how to prepare the zirconia ceramic implant with high mechanical property and excellent osteogenesis capability has important significance in the field of rapid restoration of the oral cavity which needs to meet a certain bearing function.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a zirconia ceramic implant with a three-dimensional communicated hierarchical pore structure and a preparation method thereof.

The zirconia ceramic implant with the three-dimensional communicated hierarchical pore structure comprises: the implant body and the base station are arranged above the implant body through the retention prismatic table, the implant body sequentially comprises an implant root, an implant body part and an implant neck from bottom to top, and the diameters of the implant root, the implant body part and the implant neck are sequentially increased and are provided with taper;

the root of the implant, the body of the implant and the neck of the implant are respectively provided with a first thread, a second thread and a third thread, and the thread pitches, the tooth depths and the tooth thicknesses of the first thread, the second thread and the third thread are sequentially reduced;

the implant body is hollow, a multi-level hole structure is arranged in the implant body, the multi-level hole structure comprises vertical pipelines and transverse pipelines, the vertical pipelines are connected and communicated through a plurality of transverse pipelines, a plurality of holes are formed in the wall surface of the middle part of each transverse pipeline, and a cross supporting plate is arranged in the vertical pipeline in a through-long manner; the outermost side of the multi-level hole structure is cut by the inner wall of the implant body, the multi-level hole structure is fixedly connected with the inner wall of the implant body, and the surface of the implant body is provided with a through bone-combining hole; the implant abutment and the retention prism are solid structures.

As preferable: the top section of the neck of the implant is an inverted conical surface, and the top end size of the inverted conical surface of the neck of the implant is matched with the retention prismatic table.

As preferable: the first thread, the second thread and the third thread are connected end to end in sequence, the bottom end of the first thread is located at the bottom end of the root of the implant, and the top end of the third thread extends to the inverted conical surface of the neck of the implant.

As preferable: the multi-stage pore structure comprises at least four stages of pores, the size range of the multi-stage pores of the multi-stage pore structure is 56-260 mu m, and the porosity is 60-90%; the pore size of the bone-combining pore is 100-500 mu m, and the bone-combining pore is communicated with the multi-stage pore of the multi-stage pore structure.

The preparation method of the zirconia ceramic implant with the three-dimensional communicated hierarchical pore structure comprises the following steps:

step one: the method comprises the steps that modeling software is used for carrying out model design on an implant, a base and a retention prismatic table are of solid structures, a multistage hole structure is arranged in an implant body, a plurality of bone-joint holes are formed in the implant body, and meanwhile, a first thread, a second thread and a third thread are respectively arranged at the root of the implant, the implant body and the neck of the implant;

step two: slicing the established three-dimensional implant model, and setting a printing track;

step three: manufacturing the implant layer by a material jet printing system containing zirconia ceramic particles until printing to obtain a final formed blank;

step four: degreasing and sintering the implant blank by using a sintering furnace, and finally obtaining the zirconia ceramic implant with the multistage pore structure through post-treatment.

The beneficial effects of the invention are as follows:

1) The multi-level hole structure provided by the invention is a body-centered cubic multi-level hole grid structure, takes the multi-level hole structure as an internal unit structure topology type of an additive manufacturing implant, has hole morphology structures with different directions, different pore sizes and porosities, can simultaneously realize the early formation of human tissue ingrowth and bone tissue, and is beneficial to forming good osseous combination between the implant and the bone tissue.

2) The invention adopts the design that bone-combining holes distributed on the surface of the implant body are communicated with the multi-stage hole structure inside, the multi-stage hole structure promotes the migration and infiltration of cells related to bone repair inwards along the pore canal, has good osteogenesis inducing effect, promotes the human tissue to be combined with the implant device better in a short time, leads the human tissue to generate certain tensioning effect on the implant, improves the stability, ensures higher mechanical property while ensuring higher porosity required by the human tissue, and is beneficial to the rapid recovery of oral functions.

3) The porous zirconia ceramic implant has the structural function of bearing axial load, the functional functions of human tissue ingrowth, combination, human internal bone tissue substance transmission and the like, and not only utilizes the mechanical properties such as light structural strength, rigidity and the like, but also utilizes the physical properties such as the inner surface of pores and porous body permeation and the like, ensures the normal bone tissue remodeling process, and simultaneously meets the material applicability and mechanical requirements of oral medical restoration.

4) The porous structure ceramic implant body and the base station are printed by adopting the same zirconia ceramic ink material, so that the problem that the elastic modulus of the traditional solid ceramic implant is not matched with surrounding bone tissues can be solved, and the phenomena of stability and wear resistance are prevented from being damaged in the use process. Meanwhile, zirconia has good biocompatibility, is nontoxic and harmless to human bodies, is corrosion-resistant, and combines the osteogenesis induction and bone growth conduction effects of the multi-stage pore unit structure.

5) The implant body and the base station are integrally printed and formed, so that the adjustment and involution process or the use of adhesive in the assembly process of the traditional implant body and the base station can be omitted, the secondary operation process of a patient is avoided, the assembly difficulty and the assembly period are reduced, and the mechanical stability is higher.

6) The porous material prepared by the traditional methods of adding pore-forming agent, foaming method, freeze drying and the like has low porosity, relatively difficult control of pore diameter and pore passage penetration rate, single pore structure and relatively poor mechanical properties; the ceramic implant with the internal multilevel pore body-centered cubic grid structure is manufactured by a 3D printing method of zirconia material injection, the precision of the method can reach 5-10 mu m, a multi-scale porous material with microscopic and macroscopic pores can be manufactured, the pore size is controllable, the pore structure is controllable, the internal pore is completely communicated with the three-dimensional porous implant structure, the material utilization rate can be improved, the time is saved, the cost is reduced, the advantages of high efficiency, high precision and rapid prototyping are achieved, and the bone tissue regeneration reconstruction capability of the porous structure ceramic implant can be improved by precisely controlling the pore structure, so that the porous structure ceramic implant meets the mechanical strength and bone bonding performance requirements of oral medical application.

Drawings

FIG. 1 is a schematic diagram of a front view of the present invention;

FIG. 2 is a schematic cross-sectional view of the porous structure inside the ceramic implant according to the present invention;

fig. 3 is a three-dimensional unit structure of the porous structure in the region of fig. 2A.

Reference numerals illustrate: a base 1, a retention prism 2, an implant neck 3, an implant body 4, an implant root 5, a first thread 6, a second thread 7, a third thread 8, a bone-joining hole 9 and a multi-stage hole structure 10.

Detailed Description

The invention is further described below with reference to examples. The following examples are presented only to aid in the understanding of the invention. It should be noted that it will be apparent to those skilled in the art that modifications can be made to the present invention without departing from the principles of the invention, and such modifications and adaptations are intended to be within the scope of the invention as defined in the following claims.

Example 1

As an example, as shown in fig. 1 to 3, such a zirconia ceramic implant having a three-dimensional communicating hierarchical pore structure includes: the implant body and the base station 1 are integrally formed by printing the same materials, the base station 1 is arranged above the implant body through the retention prismatic table 2, the implant body sequentially comprises an implant root 5, an implant body 4 and an implant neck 3 from bottom to top, and the diameters of the implant root 5, the implant body 4 and the implant neck 3 are sequentially increased and are provided with conicity; the top section of the implant neck 3 is an inverted conical surface, and the top end size of the inverted conical surface of the implant neck 3 is matched with the retention prismatic table 2.

As shown in fig. 1, the implant root 5, the implant body 4 and the implant neck 3 are respectively provided with a first thread 6, a second thread 7 and a third thread 8, and the thread pitches and the tooth thicknesses of the first thread 6, the second thread 7 and the third thread 8 are respectively reduced in sequence; the first thread 6, the second thread 7 and the third thread 8 are connected end to end in sequence, the bottom end of the first thread 6 is located at the bottom end of the implant root 5, and the top end of the third thread 8 extends to the inverted conical surface of the implant neck 3. When the implant is drilled from the implant root 5, the first thread 6, the second thread 7 and the third thread 8 sequentially drill into human tissues, three groups of threads with different pitches are formed, the larger the thread depth of the threads is, the larger the surface area of the implant is, the first thread 6 is designed to be a deep thread at the end of the implant root 5, so that initial contact can be increased to the greatest extent, and initial stability can be provided; the second thread 7 of the implant body 4 is a sparse thread, so that the internal stress distribution in unit area can be reduced, bone resorption is reduced, small holes are formed in the outer surface of a thread gap, and bone tissue in-growth is promoted; the third thread 8 of the implant neck 3, which has the shallowest depth, is a tight thread, which contributes to the positioning of the peripheral bone and soft tissue around the implant.

As shown in fig. 2 and 3, the implant body is hollow, a multi-stage hole structure 10 is arranged in the implant body, the multi-stage hole structure 10 comprises vertical pipelines and transverse pipelines, the vertical pipelines are connected and communicated through a plurality of transverse pipelines, a plurality of holes are formed in the middle wall surface of each transverse pipeline, a cross supporting plate is arranged in the vertical pipeline in a through-long manner, and the cross supporting plate can be crossed or a cross structure is formed by crossing a plurality of arc plates; the outermost side of the multi-level hole structure 10 is cut by the inner wall of the implant body, the multi-level hole structure 10 is fixedly connected with the inner wall of the implant body, through bone combining holes 9 are distributed on the surface of the implant body, and the bone combining holes 9 are distributed in a crisscross mode, so that the combination of human tissues and an implantation device is facilitated.

The multi-stage pore structure 10 comprises multi-stage pores, the multi-stage pore size of the multi-stage pore structure 10 ranges from 56 μm to 260 μm, and the porosity ranges from 60% to 90%; the pore size of the bone-combining pores 9 is 100-500 μm, and the bone-combining pores 9 are communicated with the inner multi-stage pore structure 10. The multi-stage pore structure 10 promotes the migration and infiltration of cells related to bone repair inwards along the pore canal, has good osteogenesis induction effect, promotes the better combination of human tissues and an implant device in a short time, ensures that the human tissues have a certain tensioning effect on the implant, improves the stability, ensures higher mechanical property while ensuring higher porosity required by the human tissues, and is beneficial to the rapid recovery of oral functions.

Example two

As another embodiment, the method for preparing the zirconia ceramic implant with the three-dimensional communication hierarchical pore structure in the first embodiment includes the following steps:

step one: designing a model of an implant by using modeling software, arranging a multi-level hole structure 10 inside the implant body, arranging a plurality of bone-combining holes 9 in the implant body, and simultaneously arranging a first thread 6, a second thread 7 and a third thread 8 on the implant root 5, the implant body 4 and the implant neck 3 respectively;

step two: slicing the established three-dimensional implant model, and setting a printing track;

step three: the implant is manufactured layer by a material jet printing system comprising zirconia ceramic particles, the material jet printing system comprising two jets, one for jetting zirconia ceramic material and the other for jetting material of the water-soluble support portion. The zirconia ceramic material comprises ceramic solid-phase particles and an auxiliary agent; the solid phase particles comprise zirconium oxide, yttrium oxide, hafnium oxide and aluminum oxide, and the auxiliary agent comprises one or more of ethylene glycol, polypropylene, polystyrene, water and other organic solvents; the content of zirconia is 70-90 wt%, the grain diameter is 35-45 nm, the content of yttria is 4.7-5.7 wt%, the content of hafnium oxide is less than 5 wt%, and the content of alumina is 0.1-0.4 wt%. Printing a support portion with a water-soluble material, the support material comprising sodium carbonate, ethylene glycol, and polyphosphate; the content of sodium carbonate is 10-40%, the content of glycol is 40-70%, and the content of polyphosphate is less than 2%, until printing to obtain the final formed blank;

step four: water enters the implant through the bone combining holes 9, and the support part printed by the water-soluble material is dissolved and removed;

step five: degreasing and sintering the implant blank by using a sintering furnace, and finally obtaining the zirconia ceramic implant with the hierarchical pore structure 10 through post-treatment.

Example III

As another embodiment, the method for preparing the zirconia ceramic implant with the three-dimensional communication hierarchical pore structure in the first embodiment specifically comprises the following steps:

step one: modeling software is used for carrying out model design on the implant, and the shape and the size corresponding to each part structure are edited; the height and the diameter of the base 1 and the width of the retention prism 2 can be correspondingly designed according to the actual patient requirement; editing the thread major diameters, the tooth-shaped intervals and the thread pitches of the first thread 6, the second thread 7 and the third thread 8 which are respectively corresponding to the peripheries of the implant neck 3, the implant body 4 and the implant root 5;

in the embodiment, the total height of the implant is 10-15 mm, the height of the abutment is 3-5 mm, the maximum diameter of the implant body is 3.5-7 mm, the minimum diameter is 2.4-3.6 mm, the wall thickness is 0.5mm, the spacing between the first threads 6 is 1-3 mm, the spacing between the second threads 7 is 0.5-1 mm, the spacing between the third threads 8 is 0.1-0.3 mm, and the thread spacing and the thread tooth thickness are gradually reduced.

Further, the bone-combining small holes 9 on the outer surface of the implant body are circular in shape, the pore size is 500 mu m, and the holes are distributed in a crisscross manner;

further, a porous structure 10 of the intra-implant body-centered cubic unit cell configuration is established, which comprises at least four levels of pores, see the corresponding portion outlined by circle a in fig. 2, i.e. fig. 3; the porous bracket with the unit configuration of 60-210 mu m is provided with pores with different pore diameters of 63 mu m, 96 mu m, 150 mu m, 204 mu m, 210 mu m and 240 mu m in the vertical direction and the transverse direction, and the porosity is 71%;

step two: slicing the established three-dimensional model, and setting a printing track; the thickness of the slice treatment corresponding to the implants with different diameters is 5-10 mu m.

Step three: manufacturing the zirconia ceramic implant layer by adopting a material spraying 3D printing system until a final formed blank is obtained by printing; the material jet printing system comprises three material spray heads which are respectively used for spraying zirconia ceramic material, hydroxyapatite material and supporting material.

The zirconia ceramic material comprises ceramic solid-phase particles and an auxiliary agent; wherein the solid phase particles comprise 70-90 wt.% of zirconia, the particle size is 35-45 nm, 4.7-5.7 wt.% of yttria, hafnium oxide with the content of less than 5wt.%, 0.1-0.4 wt.% of alumina and other oxides with the content of less than 0.1wt.%, and the ink auxiliary agent comprises one or more of ethylene glycol, polypropylene, polystyrene, water and other organic solvents.

The water-soluble support material comprises one or more of 10-40% sodium carbonate, 40-70% glycol and less than 2% polyphosphate.

The hydroxyapatite material component comprises hydroxyapatite and an auxiliary agent; spraying zirconia ceramic material and hydroxyapatite material to a printing substrate according to the system setting, evaporating the auxiliary agent under the action of the substrate at 180 ℃, and simultaneously spraying supporting material at the supporting position in the structural design process;

step four: removing water-soluble supporting materials from the printed green implant body in deionized water with constant temperature of 30 ℃, enabling water to enter the implant body through the bone-combining holes 9, and dissolving and removing the supporting parts obtained by printing the water-soluble materials; then the drying treatment is carried out in a drying oven at 70 ℃ for 20 to 30 minutes.

Step five: degreasing and sintering the implant blank by using a sintering furnace, and finally obtaining the porous zirconia ceramic implant with the multi-stage pore unit configuration through post-treatment. The blank is insulated for 1 to 3 hours at 1360 to 1580 ℃ to obtain a final sintered product, and then the final sintered product is subjected to sand blasting or acid pickling treatment to obtain a final zirconia ceramic implant; wherein the temperature rise and fall rate is 2-10 ℃/min.

The zirconia ceramic implant obtained by the process has the bending strength of 892MPa and the fracture toughness of 5.2 MPa.m ^1/2 。

Claims (5)

1. A zirconia ceramic implant with a three-dimensional communicating hierarchical pore structure, comprising: the implant comprises an implant body and a base station (1), wherein the base station (1) is arranged above the implant body through a retention prismatic table (2), the implant body sequentially comprises an implant root (5), an implant body (4) and an implant neck (3) from bottom to top, and the diameters of the implant root (5), the implant body (4) and the implant neck (3) are sequentially increased and are provided with conicity;

the implant root (5), the implant body (4) and the implant neck (3) are respectively provided with a first thread (6), a second thread (7) and a third thread (8), and the thread pitches, the thread depths and the thread thicknesses of the first thread (6), the second thread (7) and the third thread (8) are sequentially reduced;

the implant body is hollow, a multi-level hole structure (10) is arranged in the implant body, the multi-level hole structure (10) comprises vertical pipelines and transverse pipelines, the vertical pipelines are connected and communicated through a plurality of transverse pipelines, a plurality of openings are formed in the wall surface of the middle of each transverse pipeline, and a cross supporting plate is arranged in the vertical pipeline in a penetrating manner; the outermost side of the multi-level hole structure (10) is cut by the inner wall of the implant body, the multi-level hole structure (10) is fixedly connected with the inner wall of the implant body, and a through bone-combining hole (9) is arranged on the surface of the implant body;

the implant base table (1) and the retention prismatic table (2) are solid structures.

2. The zirconia ceramic implant with a three-dimensional communicating hierarchical pore structure according to claim 1, wherein: the top section of the implant neck (3) is an inverted conical surface, and the top end size of the inverted conical surface of the implant neck (3) is matched with the retention prismatic table (2).

3. The zirconia ceramic implant with a three-dimensional communicating hierarchical pore structure according to claim 2, wherein: the first thread (6), the second thread (7) and the third thread (8) are connected end to end in sequence, the bottom end of the first thread (6) is located at the bottom end of the implant root (5), and the top end of the third thread (8) extends to the inverted conical surface of the implant neck (3).

4. The zirconia ceramic implant with a three-dimensional communicating hierarchical pore structure according to claim 1, wherein: the multi-stage pore structure (10) comprises at least four stages of pores, the size range of the multi-stage pores of the multi-stage pore structure (10) is 56-260 mu m, and the porosity is 60-90%; the pore size of the bone-combining pores (9) is 100-500 mu m, and the bone-combining pores (9) are communicated with the multi-stage pores of the multi-stage pore structure (10).

5. The method for preparing a zirconia ceramic implant having a three-dimensional communicating hierarchical pore structure as set forth in claim 1 to 4, comprising the steps of:

step one: the implant is designed by using modeling software, wherein a base (1) and a retention prismatic table (2) are of solid structures, a multistage hole structure (10) is arranged in the implant body, a plurality of bone-joint holes (9) are formed in the surface of the implant body, and meanwhile, a first thread (6), a second thread (7) and a third thread (8) are respectively arranged at an implant root (5), an implant body (4) and an implant neck (3);

step two: slicing the established three-dimensional implant model, and setting a printing track;

step three: manufacturing the implant layer by a material jet printing system containing zirconia ceramic particles until printing to obtain a final formed blank;

step four: degreasing and sintering the implant blank by using a sintering furnace, and finally obtaining the zirconia ceramic implant with the multistage pore structure (10) through post-treatment.