CN112060581A

CN112060581A - Dental implant with bionic gradient modulus local functionalization and preparation method thereof

Info

Publication number: CN112060581A
Application number: CN202010896066.9A
Authority: CN
Inventors: 姜楠; 祝颂松; 谭佩洁; 毕瑞野; 应彬彬
Original assignee: Sichuan University
Current assignee: Sichuan University
Priority date: 2020-08-31
Filing date: 2020-08-31
Publication date: 2020-12-11
Anticipated expiration: 2040-08-31
Also published as: CN112060581B

Abstract

The invention provides a dental implant with bionic gradient modulus local functionalization and a preparation method thereof, wherein the preparation method comprises the following steps: mixing nano graphene and polyether-ether-ketone to obtain a mixture, adding absolute ethyl alcohol, stirring at room temperature, and performing vacuum filtration and drying to obtain 1 wt% of nano graphene/polyether-ether-ketone mixed powder; 5 wt% of nano graphene/polyether-ether-ketone mixed powder is obtained by the same method; designing a digital model of the dental implant, then performing function modeling, setting a printing path, performing 3D printing through mixed powder, cooling to room temperature, and peeling to obtain the dental implant with the local bionic gradient modulus functionalization. The invention also comprises the dental implant prepared by the method. The invention can prepare the dental implant with gradient elastic modulus and regional functional characteristics, has simple preparation process and effectively solves the problems of mismatching of the elastic modulus of the dental implant and the alveolar bone, easy looseness of the implant and the like in the prior art.

Description

Dental implant with bionic gradient modulus local functionalization and preparation method thereof

Technical Field

The invention belongs to the technical field of dental implants, and particularly relates to a dental implant with bionic gradient modulus local functionalization and a preparation method thereof.

Background

The loss of the tooth body is a common disease in the field of oral medicine, and the treatment of the loss of the tooth body by using the artificial denture prepared from the artificial material is a preferred repairing method for the disease. At present, most of materials for implanting false teeth clinically used are titanium and titanium alloy, and the implanted false teeth have the characteristics of high biocompatibility, excellent mechanical property and the like. However, the excessively high elastic modulus (>100GPa) of titanium and titanium alloys does not match the elastic modulus of natural alveolar bone, and this elastic mismatch causes the metal implant to be stressed more when stressed simultaneously with bone, which may lead to disuse atrophy of bone over time, a phenomenon known as stress shielding effect, and is one of the causes of implant loosening. In addition, the metal implant may interact with body fluid to generate electrochemical corrosion, and metal ions as hapten can cause aseptic inflammation of the implant, and also can cause bone loss at the edge of the implant to influence the stability of the implant. Therefore, the dental implant which is made of non-metallic materials and matched with the elastic modulus of the natural alveolar bone has high clinical value.

The natural alveolar bone is transited from the cortex of the bone to the cancellous bone from the crown to the root, the elastic modulus is gradually reduced, and according to the Walf's law, if the elastic modulus of the implant is matched with the natural bone in different areas, better bone healing can be achieved. The implant also has different functions in different directions, needs to be tightly combined with peripheral alveolar bone at the bottom end of the implant, lays a stable foundation for the implant, needs to be matched with the elastic modulus of the peripheral alveolar bone at the top end of the implant, prevents the loss of the peripheral bone caused by stress shielding effect, and reduces the probability of looseness of the implant. Most of the existing dental implants which are commonly used clinically are uniform modulus dental implants which are not prepared by a nonfunctional gradient material.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a dental implant with bionic gradient modulus local functionalization and a preparation method thereof, which can be used for preparing the dental implant with gradient elastic modulus and regional functionalization characteristics, have the advantages of low raw material cost, good processing performance, simple and easy operation of preparation process, can be used for quickly preparing the dental implant, effectively solves the problems of mismatch of elastic modulus of the dental implant and alveolar bone, easy looseness of the implant and the like in the prior art, and is convenient for popularization and use.

In order to achieve the purpose, the technical scheme adopted by the invention for solving the technical problems is as follows: the preparation method of the dental implant with the bionic gradient modulus local functionalization is provided, and comprises the following steps:

(1) mixing 1 wt% of nano graphene and polyether-ether-ketone to obtain a mixture, adding absolute ethyl alcohol into the mixture, magnetically stirring at room temperature for 20-40min, and sequentially performing vacuum filtration and drying to obtain 1 wt% of nano graphene/polyether-ether-ketone mixed powder; 5 wt% of nano graphene/polyether-ether-ketone mixed powder is obtained by the same method;

(2) designing a digital model of the dental implant, performing function modeling, setting a printing path, selecting each layer to be printed and deflected by 90 degrees, performing 3D printing on the 1 wt% of nano graphene/polyether-ether-ketone mixed powder and the 5 wt% of nano graphene/polyether-ether-ketone mixed powder obtained in the step (1), cooling to room temperature, and peeling to obtain the dental implant with the local bionic gradient modulus function.

Further, in the step (1), 8-12ml of absolute ethyl alcohol is added into each gram of the mixture.

Further, in the step (1), 10ml of absolute ethanol was added per gram of the mixture.

Further, in the step (1), drying is carried out at the temperature of 55-65 ℃.

Further, in the step (1), drying is carried out at the temperature of 60 ℃.

Further, in the step (2), gradient material function modeling is performed according to the scheme that the dental implant gradually makes linear transition from 5 wt% of nano graphene/polyether ether ketone mixed powder to 1 wt% of nano graphene/polyether ether ketone mixed powder from bottom to top.

The dental implant with bionic gradient modulus local functionalization prepared by the preparation method.

In summary, the invention has the following advantages:

1. the invention can prepare the dental implant with gradient elastic modulus and regional functional characteristics, has low raw material cost and good processing performance, can avoid the loss of bones at the edge of the implant, has better stability, simple preparation process and easy operation, can quickly prepare the dental implant, effectively solves the problems of unmatched elastic modulus of the dental implant and alveolar bone, easy looseness of the implant and the like in the prior art, and is convenient for popularization and use.

2. Aiming at the problem of mismatching of the elastic modulus of the pure titanium implant and the natural bone, a high polymer material of Polyetheretherketone (PEEK) matched with the elastic modulus of the natural bone is used as a base material, high-concentration nano graphene and the PEEK are compounded at the bottom end of the implant to improve the osteogenesis potential of the PEEK, and low-concentration nano graphene and the PEEK are compounded at the top end of the implant to enhance the mechanical property of the material. A functional gradient design composite dental implant with linearly increased nano-graphene content from top to bottom is prepared by a bi-component 3D printer through a gradient modeling anisotropic material printing method of nano-graphene/polyether-ether-ketone composite materials with different components.

3. The gradient dental implant with gradually changed chemical components can effectively relieve local stress enhancement of the abrupt change of the elastic modulus of the interface, optimize the distribution of the internal stress of the material and avoid the structural defect of the material caused by stress concentration. The gradient design can enhance the anisotropic performance of the dental implant and meet the different performance requirements of different parts of the dental implant.

4. Through a 3D printing method, the polyether-ether-ketone and the polyether-ether-ketone/nano graphene are mixed layer by layer and printed in a mixed mode, the composite material dental implant with the integrated structure, the modulus gradient and the local functionalization can be prepared, and the elastic modulus of the dental implant is gradually increased from bottom to top and is matched with the elastic modulus of the natural alveolar bone in different areas. The dental implant has higher osteogenesis efficiency at the root of the tooth, the osseointegration is firm, the modulus matching degree of the healing abutment and cortical bone is high, and the risk of marginal bone loss and soft tissue retraction is reduced. The dental implant can greatly reduce the risk of loosening of the implant and improve the success rate of the implant. In addition, the PEEK dental implant has radiotransparency, does not generate artifacts in imaging examination, is convenient for clinical imaging tracking to observe the curative effect of the implant, does not influence radiotherapy, and can be used for reconstructing the dentition after the radiotherapy of head and neck tumors.

5. Firstly, nano graphene and polyether-ether-ketone are added, and then absolute ethyl alcohol is added for magnetic stirring, so that the nano graphene is uniformly dispersed in the polyether-ether-ketone, the subsequent printing is facilitated, and the obtained dental implant is uniform in component; designing a digital model of the dental implant and performing functional modeling, wherein each layer of printing is deflected by 90 degrees so that the materials are arranged in a staggered mode integrally and are distributed uniformly; in the 3D printing process, the mixing device continuously works to realize dynamic mixing among different material components, and the digitized feeding of the material is promoted through a material printing process of fused deposition accumulation molding, so that the continuous gradient distribution of the printing material components in the z-axis direction is realized. And after printing is finished, stripping the test piece after the test piece is fully cooled to room temperature to obtain the dental implant with the bionic gradient modulus local functionalization.

Drawings

FIG. 1 is a schematic diagram of an in vivo and in vitro experimental specimen;

FIG. 2 is a statistical plot of tensile, compressive, and flexural moduli;

FIG. 3 is a schematic view of a tensile specimen for fracture surface scanning electron microscope observation;

FIG. 4 is a schematic view of the observation of BMSCs after 2h inoculation by a scanning electron microscope;

FIG. 5 is a schematic diagram showing the proportion of cells in the proliferative phase;

FIG. 6 is a graph showing the results of quantitative determination of alkaline phosphatase (ALP);

FIG. 7 is a schematic diagram of RT-PCR detection of osteogenesis related gene expression;

FIG. 8 is a diagram showing the expression of the protein involved in the detection of osteogenesis by WB;

FIG. 9 is a schematic view of the process of implanting the material into the lower jaw of a rabbit;

FIG. 10 is a three-dimensional reconstructed image of a 4-week and 12-week sample;

FIG. 11 is a 4 week, 12 week sample Micro CT data analysis;

FIG. 12 shows the results of methylene blue acid magenta staining;

fig. 13 is an analysis of 4-week and 12-week bone contact ratio data.

Detailed Description

Example 1

A preparation method of a dental implant with bionic gradient modulus local functionalization comprises the following steps:

(1) mixing 1 wt% of nano graphene and polyether-ether-ketone to obtain a mixture, then adding 8ml of absolute ethyl alcohol into each gram of the mixture, magnetically stirring at room temperature for 20min, sequentially performing vacuum filtration and drying at 55 ℃ to obtain 1 wt% of nano graphene/polyether-ether-ketone mixed powder; 5 wt% of nano graphene/polyether-ether-ketone mixed powder is obtained by the same method;

(2) designing a digital model of the dental implant, performing gradient material function modeling according to a scheme that the dental implant is gradually linearly transited from 5 wt% of nano graphene/polyether-ether-ketone mixed powder to 1 wt% of nano graphene/polyether-ether-ketone mixed powder from bottom to top, setting a printing path, selecting each layer of printing deflection 90 degrees, respectively placing the 1 wt% of nano graphene/polyether-ether-ketone mixed powder and the 5 wt% of nano graphene/polyether-ether-ketone mixed powder obtained in the step (1) in different material barrels of a bi-component 3D printer, performing 3D printing, cooling to room temperature, and peeling to obtain the dental implant with the local bionic gradient modulus.

Example 2

(1) mixing 1 wt% of nano graphene and polyether-ether-ketone to obtain a mixture, then adding 10ml of absolute ethyl alcohol into each gram of the mixture, magnetically stirring at room temperature for 30min, sequentially performing vacuum filtration and drying at 60 ℃ to obtain 1 wt% of nano graphene/polyether-ether-ketone mixed powder; 5 wt% of nano graphene/polyether-ether-ketone mixed powder is obtained by the same method;

Example 3

(1) mixing 1 wt% of nano graphene and polyether-ether-ketone to obtain a mixture, then adding 12ml of absolute ethyl alcohol into each gram of the mixture, magnetically stirring at room temperature for 40min, sequentially performing vacuum filtration and drying at 65 ℃ to obtain 1 wt% of nano graphene/polyether-ether-ketone mixed powder; 5 wt% of nano graphene/polyether-ether-ketone mixed powder is obtained by the same method;

Experimental example 1

Mechanical property experiment: the method comprises the steps of fully mixing nano graphene with different mass fractions (0.1%, 0.5%, 1%, 2% and 5%) and polyether ether ketone at 367 ℃ by a melt blending method, preparing a test piece (shown in figure 1) required by in-vivo and in-vitro experiments by a hot press molding method, and preparing a mechanical test piece meeting the international standard of ISQ (in-line chemical equilibrium) by an injection molding method.

Each group is provided with 5 parallel samples, a universal mechanical detector is used for exploring the bending, compression and tensile moduli of the material, and the fracture surfaces of each group of test pieces stretched to fracture are subjected to a scanning electron microscope, and the results are respectively shown in figures 2-3.

As can be seen from fig. 2 to 3, the mechanical properties of PEEK can be improved in two dimensions of stretching and bending by adding 0.1%, 0.5% and 1% concentration of nanographene. However, the addition of 2% and 5% nanographene leads to partial reduction in the tensile and compressive properties of the composite material.

Experimental example 2

In vitro cytology experiments: SD rat-derived BMSCs were isolated and cultured by total bone marrow adherent method. After cells are inoculated on the surfaces of PEEK and G-PEEK materials (nano graphene/polyether ether ketone), the morphology of BMSCs and the influence of G-PEEK on cell adhesion are observed by using a Scanning Electron Microscope (SEM), which is shown in figure 4; the effect of G-PEEK on cell proliferation was investigated by flow cytometry detection, see fig. 5; after 7 days of osteogenesis induction of BMSCs inoculated on the surface of PEEK and G-PEEK, the effect of G-PEEK on osteogenic differentiation of rat BMSCs was examined by quantitative detection of ALP (FIG. 6), RT-PCR (FIG. 7), Western Blot (FIG. 8), and the like.

As can be seen from FIG. 4, the cells grown on the surface of the PEEK material of the control group were in a primary adhesion state, and the cells were in an irregular hemispherical shape and were not fully stretched. BMSCs grown on the surface of the G-PEEK group adhere well, cells adhere to the surface of the material in a flat shape, stretch sufficiently and present a typical polygonal shape. With the gradually increased content of nano graphene, the cells are more fully stretched. The adhesion of the cells on the surface of the control group PEEK material is poor through observation under a high power lens, compared with a G-PEEK group, the number and the length of the filamentous pseudo feet are obviously less, the cells visible on the G-PEEK material of the experimental group are tightly connected with the material through the filamentous pseudo feet, and the cells are more tightly adhered on the surface of the material along with the addition of the content of the nano graphene. Scanning electron microscope results show that the addition of the nano graphene with the concentration in the research can promote the adhesion of rat BMSCs on the surface of the PEEK material.

As can be seen from fig. 5, after BMSCs were cultured on the material surface for 3 days, the proportion of cells in the growth phase on each group of materials was relatively close, about 20%, and the difference between groups was not significant. Flow cytometry detection results suggest that the addition of nano-graphene with the concentration in the study has no obvious influence on the proliferation of rat BMSCs cells on a polyetheretherketone material.

As can be seen from FIG. 6, after 7 days of osteogenesis induction, the relative ALP activity of the cells on the surface of the G-PEEK group material is obviously improved compared with that of the PEEK control group, and the relative ALP activity of the adhered cells on the G-PEEK group material is in an increasing trend along with the increase of the content of the nano graphene. Wherein, the 0.1% G-PEEK group has no obvious difference compared with a control group, the 0.5% G-PEEK has obviously increased ALP expression compared with the control group, and the difference has statistical significance (p is less than 0.01). There was no significant difference in ALP expression between the three groups of 0.5%, 1%, 2% G-PEEK. The ALP expression of the 5% G-PEEK group is obviously increased compared with that of the former five groups, and the difference has statistical significance (p is less than 0.001).

As can be seen from FIG. 7, except for the 0.1% G-PEEK group, the expression of the osteogenesis related gene of each experimental group was up-regulated compared to the control group, and the difference was statistically significant. With the increase of the content of the nano graphene, the expression of each component bone related gene is basically in a gradually up-regulated trend. Therefore, 0.5 to 5 percent of G-PEEK obviously promotes the expression of osteogenesis related genes of BMSCs.

As can be seen from FIG. 8, the expression levels of OPN, RUNX2 and ALP were significantly increased in the experimental group compared to the control group, and the difference between the groups was statistically significant (P < 0.05). And the bone-promoting effect has obvious concentration dependence, and the expression level of the bone formation related protein is up-regulated along with the increase of the concentration of the added nano graphene.

In vitro cytology experiment results show that the addition of the nano graphene can obviously promote the adhesion and osteogenic differentiation of rat BMSCs on the surface of a PEEK material, the promotion effect has a concentration dependence relationship, and the higher the content of the nano graphene in the composite material is, the stronger the promotion effect is.

Experimental example 3

In vitro animal experiments: the G-PEEK and PEEK materials were implanted into rabbit mandible bodies (see FIG. 9), and the osseointegration effect of the G-PEEK was evaluated based on the area of new bone around the material and the bone contact rate. Materials were obtained at 4 and 12 weeks of implantation, and the area of new bone and bone contact rate around the material were evaluated by Micro CT detection, hard tissue section staining, and the like. As the experimental results in the experimental example 2 show that the three groups of 0.5%, 1% and 2% have no obvious difference in promoting the osteogenic differentiation of the cells, in the experimental example, the 1% G-PEEK experimental group is reserved, and the pure PEEK control group, the 0.1% PEEK group, the 1% PEEK group and the 5% PEEK group are selected for the experiment.

At 4 and 12 weeks post-surgery, 3 rabbits were sacrificed at random for material selection, subjected to Micro CT examination, and analyzed for ROI by μ CT Evaluation programmv 6 (ROI is within 250 μm of sample circumference). The three-dimensional reconstructed picture is shown in fig. 10, and the ROI statistical analysis results of 4 weeks and 12 weeks are shown in fig. 11; after Micro-CT detection, samples are subjected to hard tissue embedding, slicing and methylene blue acid fuchsin dyeing, the osseointegration effect of the implant-bone interface after G-PEEK is observed under an optical microscope, and the methyl blue acid fuchsin dyeing result is shown in figure 12; to more intuitively evaluate the effect of the G-PEEK composite implant on the osseointegration at the implant-bone interface, quantitative analysis of the implant-bone contact area/total area in methylene blue acid fuchsin stained pictures was performed using Image J software, with the results shown in fig. 13.

As can be seen from fig. 10, the PEEK material itself was not visualized, and the white high-density portion represents the new bone tissue around the perimeter of the material. As can be seen by three-dimensional reconstruction, the surfaces of the G-PEEK group materials are covered by new bones to a certain degree after 4 weeks, and almost no obvious new bones exist on the surfaces of the PEEK group materials. And the coverage area of the new bone on the surface of the G-PEEK material is increased along with the increase of the content of the nano graphene. The three-dimensional reconstruction result after 12 weeks shows that the G-PEEK and the PEEK material have obvious bone growth along with the extension of the implantation time, the new bone around the G-PEEK group material is obviously thickened in 4 weeks, the bone coverage area is obviously increased, and a thin layer of new bone appears on the surface of the PEEK control group material. The new bone mass of the G-PEEK group is more than that of the PEEK group.

As can be seen in FIG. 11, bone volume/total volume (BV/TV) was significantly higher in the 1% and 5% G-PEEK groups at 4 weeks than in the control group, and the comparative differences between the groups were statistically significant (P < 0.01). Meanwhile, the number (Tb.N) and the thickness (Tb.Th) of the trabeculae also show an increasing trend along with the increase of the content of the nano graphene in the G-PEEK material. The trabecular bone spacing (tb.sp) decreases with increasing nanographene content.

As can be seen from fig. 12, after 4 weeks of implantation, there were almost no new bones on the PEEK group surface, the new bone area and trabecular thickness of each G-PEEK group were higher than those of the PEEK group, and the new bone volume gradually increased with the increasing nano-graphene content. After 12 weeks of implantation, the coverage area of the new bone of each group is obviously increased compared with 4 weeks, thin layers of new bone appear on the surface of the PEEK group material, the area of the new bone on the surface of the G-PEEK group material is obviously higher than that of the PEEK group material, and along with the increase of the content of the nano graphene, the area of the new bone is increased, and the bone trabecula is tightly adhered to the surface of the material.

As can be seen from FIG. 13, after 4 weeks of implantation, with the addition of the nanographene, the bone contact ratio showed an upward trend, no significant difference was observed between the 0.1% G-PEEK group and the pure PEEK group, the bone contact ratio was significantly higher between the 1% and 5% G-PEEK groups than that of the PEEK group, and the comparative difference between the groups was statistically significant (P < 0.01). After 12 weeks of implantation, the bone contact ratio of each G-PEEK group is still obviously higher than that of the PEEK group, the difference is statistically significant (P is less than 0.05), and the 0.1%, 1% and 5% G-PEEK groups have relatively complete bone contact, but the difference between the groups is not statistically significant.

In-vitro animal experiment results show that compared with pure Polyetheretherketone (PEEK), the nano-graphene/polyetheretherketone composite implant (G-PEEK group) can remarkably promote the bone integration of an interface after being implanted into a rabbit mandible, and the bone integration capability is improved along with the increase of the content of the nano-graphene in the composite material.

In conclusion, when the mass fraction of the nano graphene is low (0.1% -1%), the mechanical properties of the material can be improved. When the mass fraction of the nano graphene is higher (2% -5%), the osseointegration capability of the material is more excellent. Therefore, the functional gradient material dental implant is designed by adopting 1-5 wt% of the nano graphene/polyether-ether-ketone composite material, and the effect is best.

While the present invention has been described in detail with reference to the illustrated embodiments, it should not be construed as limited to the scope of the present patent. Various modifications and changes may be made by those skilled in the art without inventive step within the scope of the appended claims.

Claims

1. The preparation method of the dental implant with the bionic gradient modulus local functionalization is characterized by comprising the following steps:

2. The method for preparing a dental implant with biomimetic gradient modulus local functionalization according to claim 1, wherein in the step (1), 8-12ml of absolute ethyl alcohol is added to each gram of the mixture.

3. The method for preparing a dental implant with biomimetic gradient modulus localized functionalization according to claim 2, wherein in the step (1), 10ml of absolute ethanol is added per gram of the mixture.

4. The method for preparing a dental implant with biomimetic gradient modulus localized functionalization according to claim 1, wherein in the step (1), the drying is performed at a temperature of 55-65 ℃.

5. The method for preparing a dental implant with biomimetic gradient modulus localized functionalization according to claim 4, wherein in the step (1), the drying is performed at a temperature of 60 ℃.

6. The method for preparing a dental implant with biomimetic gradient modulus local functionalization according to claim 1, wherein in the step (2), the gradient material function modeling is performed according to a scheme that the dental implant gradually makes a linear transition from 5% of nano graphene/polyether ether ketone mixed powder to 1 wt% of nano graphene/polyether ether ketone mixed powder from bottom to top.

7. A dental implant with biomimetic gradient modulus localized functionalization made by the preparation method of any one of claims 1-6.