Composite bone graft material based on bletilla striata polysaccharide and autologous tooth bone meal as well as preparation method and application of composite bone graft material

Abstract

The invention discloses a composite bone graft material based on bletilla striata polysaccharide and autologous tooth bone meal as well as a preparation method and application of the composite bone graft material. The preparation method comprises the following steps: preparing bletilla striata polysaccharide, namely BSP, from bletilla striata; the method comprises the following steps: pretreating extracted teeth, and crushing to obtain autologous tooth bone powder, namely AutoBT; dissolving the BSP in water, and uniformly stirring to obtain a BSP solution; the AutoBT is poured into the BSP solution, and after standing and stirring, an AutoBT solution loaded with BSP is obtained; and carrying out vacuum drying on the AutoBT solution loaded with the BSP, and carrying out ultraviolet sterilization to obtain the composite bone graft material. The material can be applied to repairing of oral cavity bone defects, bletilla striata polysaccharide has the effects of resisting inflammation, inhibiting bacteria, promoting osteogenesis and inhibiting osteoclast, the bone steady state unbalance state in the periodontitis environment is effectively reversed, meanwhile, autologous tooth bone powder accelerates bone tissue regeneration and integration by means of the natural bionic structure and high porosity of the autologous tooth bone powder, and the bone tissue regeneration effect is improved. The risks of postoperative infection and immunological rejection are reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedical materials, and in particular relates to a composite bone transplant material based on bletilla striata polysaccharide and autologous tooth bone powder, and a preparation method and application thereof. Background Art

[0002] Periodontitis is one of the leading causes of tooth loss among adults in my country, leading to alveolar bone resorption and soft tissue inflammation. Six months after tooth extraction, patients with severe periodontitis experience vertical alveolar bone resorption rates ranging from 11% to 22%, and horizontal resorption rates ranging from 29% to 63%. 62.4% of patients with periodontitis report that post-extraction site preservation is suboptimal due to a lack of the necessary conditions for bone regeneration—damaged alveolar bone, limited space availability, and reduced cellularity and blood vessels.

[0003] In clinical practice, various bone graft substitute materials are often used for bone grafting surgery. Among them, the autologous bone material is limited and the donor site is severely traumatized. The risk of immune rejection of xenogeneic bone is high. It lacks anti-inflammatory and antibacterial functions, and the inflammatory response and infection are highly prevalent, leading to consequences such as prolonged bone defect healing and insufficient bone mass, which in turn increases the difficulty of repair-oriented implant treatment.

[0004] Bletilla striata polysaccharide (BSP) is rich in polysaccharides and has anti-inflammatory, antibacterial, and healing-promoting properties. Autologous tooth bone powder (AutoBT), prepared from discarded patient teeth, has high biocompatibility and a porous structure that is conducive to osteogenesis. However, existing technologies have not yet combined these two methods to synergistically enhance bone regeneration in inflammatory environments. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems of difficulty in osteogenesis in an inflammatory environment and high incidence of postoperative reactions and infections in existing bone transplant materials. The present invention provides a composite bone transplant material based on bletilla polysaccharide loaded on autologous dental bone powder, as well as its preparation method and application. The composite bone transplant material has the synergistic effect of regulating the inflammatory microenvironment and efficient osteogenesis.

[0006] The present invention adopts the following technical solution: a method for preparing a composite bone transplant material based on Bletilla striata polysaccharide and autologous tooth bone powder, comprising the following steps:

[0007] Step 1: preparing Bletilla striata polysaccharide (BSP) from Bletilla striata;

[0008] Step 2: After pre-treatment, the extracted tooth is crushed to obtain autologous tooth bone powder (AutoBT);

[0009] Step 3: dissolving the BSP in water and stirring to obtain a BSP solution;

[0010] Step 4: pouring the AutoBT into the BSP solution, allowing it to stand and stirring to obtain a BSP-loaded AutoBT solution;

[0011] Step 5: vacuum drying and ultraviolet sterilization of the BSP-loaded AutoBT solution to obtain a composite bone transplant material.

[0012] Furthermore, in step 1, the preparation process of the BSP specifically includes:

[0013] Step (1): crushing and sieving the bletilla striata to obtain bletilla striata powder;

[0014] Step (2): taking the Bletilla striata powder, mixing it with water in a ratio of 1: (20-40) to obtain a mixed solution, extracting the mixed solution at 70-90° C. for 2 hours, repeating the extraction multiple times to obtain an extract, wherein the preferred ratio is 1:20 and the preferred temperature is 80° C.;

[0015] Step (3): filtering the extract, concentrating the filtrate under reduced pressure in a rotary evaporator to obtain a finished product, adding ethanol to the finished product and filtering to obtain a precipitated product;

[0016] Step (4): dissolving the precipitated product in step (3) in water, deproteinizing and freeze-drying the product by Sevag method, dialysis, adding ethanol to the product, filtering to obtain a BSP precipitated product, and drying and crushing the product to obtain Bletilla striata polysaccharide.

[0017] Furthermore, in step (3) and step (4), the ethanol is 95% by volume and the amount added is 3 times that of the solute; the finished product is a thick paste with a water content of 15-20%; the drying temperature in step (4) is 40-60°C; the preferred drying temperature is 50°C.

[0018] Furthermore, in step 2, the pretreatment of the extracted tooth includes: removing soft tissue and enamel of the extracted tooth by a rapid turbine, extracting the pulp and decayed tooth, retaining the healthy dentin part, blowing the healthy dentin part dry with an air gun until no moisture remains and sterilizing it by ultraviolet light.

[0019] Furthermore, in step 2, the pulverization is performed using an autologous dental bone grinder, and the particle size of the autologous dental bone powder is 0.5-0.7 mm.

[0020] Furthermore, in step 3, the BSP concentration of the BSP solution is no more than 7%.

[0021] Furthermore, in step 4, the static stirring is specifically to stand for at least 3 hours and stir for one minute every hour; so as to allow the BSP to be evenly loaded on the AutoBT.

[0022] Furthermore, in step 5, the vacuum drying is specifically to spread the BSP-loaded AutoBT solution flatly on a sterile tray and place it in a vacuum dryer for drying for at least 24 hours; the composite bone graft material is sealed and stored in a sterile environment at -20°C for future use.

[0023] A composite bone transplant material based on bletilla striata polysaccharide and autologous tooth bone powder is obtained by using any of the above preparation methods.

[0024] The application of the composite bone transplant material based on bletilla striata polysaccharide and autologous tooth bone powder in the preparation of oral bone defect repair materials.

[0025] Beneficial effects:

[0026] The present invention significantly improves the effect of oral bone defect repair by combining Bletilla striata polysaccharide with autologous tooth bone powder to form a composite bone transplant material. Bletilla striata polysaccharide exerts anti-inflammatory and antibacterial effects and promotes osteogenesis and inhibits osteoclastogenesis, effectively reversing the imbalance of bone homeostasis in the periodontitis environment. At the same time, autologous tooth bone powder accelerates bone tissue regeneration and integration by virtue of its natural biomimetic structure and high porosity, and reduces the risk of postoperative infection and immune rejection. The autologous tooth bone powder and Bletilla striata polysaccharide in the material further promote angiogenesis and cell secretion of osteogenic factors, solving the problems of traditional bone transplant materials in the inflammatory environment with difficulty in osteogenesis and high incidence of postoperative reactions and infections. The composite bone transplant material has the characteristics of anti-inflammatory and antibacterial, efficient osteogenesis and long-term stability, and is particularly suitable for the repair of complex bone defects in periodontitis patients after tooth extraction, providing a more reliable treatment plan for clinical practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the process for preparing autologous tooth bone powder according to an embodiment of the present invention;

[0028] Figure 2 Schematic diagram of a composite bone transplant material of different concentrations of Bletilla striata polysaccharide and autologous tooth bone powder according to an embodiment of the present invention;

[0029] Figure 3 This is a SEM of a composite bone graft material according to an embodiment of the present invention;

[0030] Figure 4 This is a 2000x SEM image of a composite bone graft material, allogeneic bone, and xenogeneic bone according to an embodiment of the present invention;

[0031] Figure 5 This is an EDS analysis of a composite bone graft material according to an embodiment of the present invention;

[0032] Figure 6 This is a diagram showing the cytotoxicity assay results of Bletilla striata polysaccharide according to an embodiment of the present invention;

[0033] Figure 7 This is a graph showing the test results of the effect of Bletilla striata polysaccharide on RAW264.7 cell viability and cytokine secretion according to an embodiment of the present invention;

[0034] Figure 8This is the anti-inflammatory activity test result of Bletilla striata polysaccharide according to one embodiment of the present invention;

[0035] Figure 9 This is a diagram showing the results of stem cell genotype expression determination according to one embodiment of the present invention;

[0036] Figure 10 These are CR images of alveolar bone taken 2 and 4 weeks after autologous tooth bone powder was immediately implanted in a beagle dog after tooth extraction according to an embodiment of the present invention;

[0037] Figure 11 A pre-operative and post-operative comparison of mandibular alveolar bone height according to an embodiment of the present invention;

[0038] Figure 12 This is a histological section of the bone graft area according to an embodiment of the present invention;

[0039] Figure 13 3D model diagrams before and after surgery according to an embodiment of the present invention;

[0040] Figure 14 This figure shows the test results of autologous tooth bone powder and Bio-Oss bovine bone powder in bone augmentation for orthodontic patients according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The following embodiments of the technical solution of the present invention are described in detail. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are therefore only used as examples and are not intended to limit the scope of protection of the present invention.

[0042] The experimental methods in the following examples, unless otherwise specified, are all conventional methods. The experimental materials used in the following examples, unless otherwise specified, were purchased from conventional reagent stores. The quantitative experiments in the following examples were all repeated three times, and the data are the average or mean ± standard deviation of the three repeated experiments.

[0043] The autologous tooth bone powder used in the following examples all comes from the patient's extracted teeth, and the white striata used all complies with the relevant provisions of the main text of the Chinese Pharmacopoeia (2017 edition). Before feeding, it was identified that the actual medicinal materials were consistent with their names and the quality met the standards; when preparing a composite bone transplant material based on white striata polysaccharide loaded on autologous tooth bone powder, the solution was saturated when the white striata polysaccharide concentration reached 7%, so the maximum concentration of white striata polysaccharide added during preparation in the example was 7%.

[0044] Example:

[0045] 1. Prepare Bletilla striata polysaccharide BSP by the following steps:

[0046] Step 1: Grind and sieve the Bletilla striata slices, and weigh 30g of Bletilla striata powder;

[0047] Step 2: Take the Bletilla striata powder prepared in step 1, add distilled water at a solid-liquid ratio of 1:20, extract at 80°C for 2 hours, and repeat the extraction three times to obtain an extract;

[0048] Step 3: Filter the extract, and concentrate the filtrate under reduced pressure in a rotary evaporator to obtain a thick paste-like product with a water content of 15%. Add 95% ethanol with a volume fraction of 3 times that of the product to the product to precipitate, and filter;

[0049] Step 4: Take the precipitate, add 10 mL of distilled water to dissolve it, deproteinize it by Sevag method, freeze-dry it, dialyze it, and add 3 times the volume of the product to the dialyzed product again with 95% ethanol to precipitate it;

[0050] Step 5: Filter the precipitate in step 4, take the precipitate, dry it at 50°C and grind it to obtain Bletilla striata polysaccharide powder.

[0051] Using 3 volumes of ethanol has the following unique benefits: 1. Complete precipitation: 3 volumes of ethanol ensures that the ethanol concentration in the solution is high enough to fully precipitate impurities. If the amount of ethanol is insufficient, incomplete precipitation may occur due to insufficient concentration gradient.

[0052] 2. Operational feasibility: While an excess of ethanol (e.g., 5x) can improve precipitation efficiency, it increases subsequent ethanol recovery costs and may make the precipitate too dense, increasing filtration difficulty. A 3x volume is a commonly used empirical value that balances effectiveness and cost.

[0053] 2. Prepare the Autologous Tooth Bone Powder AutoBT by the following steps:

[0054] Step 1: Take the patient's lost / extracted tooth and use a turbine to remove soft tissue and enamel, then extract the pulp. The decayed tooth, while preserving the healthy dentin, is then air-dried to remove any remaining moisture and sterilized with ultraviolet light.

[0055] Step 2: Take the teeth processed in step 1 and place them The automatic bone grafting system (BMK-AUTO-02) was used to grind the bone into 0.5-0.7 mm to obtain autologous bone powder.

[0056] Step 3: Seal the bone powder and store it in a sterile environment at -20℃ until use.

[0057] like Figure 1 Schematic diagram of the preparation process of autologous tooth bone powder, where A is the extracted tooth; B is the pretreatment of the tooth; C is the grinding of the tooth; and D is the preparation of autologous tooth bone powder.

[0058] 3. Prepare the composite bone transplant material of Bletilla striata polysaccharide loaded with autologous tooth bone powder by the following steps:

[0059] Step 1: Weigh Bletilla striata, crush it, and then perform enzymatic hydrolysis. Then, precipitate it with ethanol to remove impurities. Deproteinize it with the Sevag method and freeze-dry it to obtain BSP.

[0060] Step 2: Remove the tooth by removing the soft tissue, enamel, pulp and disinfection. Autologous tooth bone powder AutoBT was prepared systematically;

[0061] Step 3: Dissolve the BSP prepared in step 1 in 10 ml of distilled water to prepare a 3% solution and stir until well mixed.

[0062] Step 4: Immerse 500 mg of pretreated AutoBT in the solution prepared in step 3, let it stand at room temperature for 3 hours, and stir for 1 minute every hour to ensure that the BSP is evenly loaded on the AutoBT;

[0063] Step 5: Spread the BSP-loaded AutoBT on a sterile tray and dry it in a vacuum desiccator for 24 hours;

[0064] Step 6: After ultraviolet sterilization, the composite bone graft material of 3% BSP and AutoBT was obtained, which was sealed and stored in a sterile environment at -20°C for future use.

[0065] By changing the preparation process of the composite bone graft material in which Bletilla striata polysaccharide is loaded on autologous dental bone powder: the specific operating steps of step 1 and step 2 refer to the preparation methods 1 and 2 above, respectively; the concentration of the BSP solution in step 3 is 5% and 7%, so as to prepare a composite bone graft material with a 5% BSP concentration and a composite bone graft material with a 7% BSP concentration.

[0066] Performance testing:

[0067] like Figure 2 , the composite bone graft material prepared in the embodiment of the present invention, wherein in Figure A, from left to right are composite bone graft materials prepared with 3%, 5%, and 7% BSP concentrations, and Figure B is a composite bone graft material prepared with 7% BSP concentration;

[0068] like Figure 3 , SEM images of composite bone graft materials, including A. 3% Bletilla striata polysaccharide + autologous dental bone powder 2k times; B. 3% Bletilla striata polysaccharide + autologous dental bone powder 5k times; C. 5% Bletilla striata polysaccharide + autologous dental bone powder 2k times; D. 5% Bletilla striata polysaccharide + autologous dental bone powder 5k times; E. 7% Bletilla striata polysaccharide + autologous dental bone powder 2k times; F. 7% Bletilla striata polysaccharide + autologous dental bone powder 5k times;

[0069] like Figure 4 The composite bone graft material of this embodiment shown in Figure A, and the conventional allogeneic bone in Figure B and xenogeneic bone in Figure C on the market;

[0070] pass Figure 3 and Figure 4 As can be seen, the composite bone graft material of the present invention has a porosity of up to 76.5%, a pore size of (2.77±0.31) μm, and hydroxyapatite crystals on the surface, with Bletilla striata polysaccharide crystals surrounding the pores (the crystals do not block the pores). Allograft bone has more micropores, with a pore size of (1.21±0.36) μm, and the most surface crystals. Xenograft bone has the lowest porosity, with a pore size of (1.50±0.19) μm, a smooth surface, and minimal crystals. In contrast, the composite bone graft material has regular grooves, high porosity, and is easily permeable to cells. Its surface topology also facilitates cell adhesion and mineral deposition.

[0071] like Figure 5 , EDS analysis of composite bone graft materials, A.3% Bletilla striata polysaccharide + autologous tooth bone powder; B.5% Bletilla striata polysaccharide + autologous tooth bone powder C.7% Bletilla striata polysaccharide + autologous tooth bone powder; Figure 5 It can be seen that the composite bone graft material in which Bletilla striata polysaccharide is loaded on autologous dental bone powder is mainly composed of calcium, phosphate and oxygen atoms. The moderate Ca / P of the composite bone graft material is close to the physiological bone regeneration rate. The composite bone graft material has a high magnesium content. Magnesium is a key auxiliary factor for osteoblast proliferation and differentiation. It can activate the expression of osteoblast marker enzymes such as alkaline phosphatase (ALP), promote osteoblast activity, and promote bone formation by regulating the MAPK signaling pathway; it can also inhibit osteoclast differentiation by reducing the RANKL / OPG ratio, reduce bone absorption, and thus maintain bone remodeling balance; it can also promote angiogenesis by upregulating vascular endothelial growth factor (VEGF), providing nutritional support for bone regeneration. This shows that the composite bone graft material of the present invention has good osteogenesis potential.

[0072] like Figure 6 As shown, a blank test group, a glass ionomer (GIC) group, a 3% BSP-GIC group, a 5% BSP-GIC group, and a 7% BSP-GIC group were set up to conduct an in vitro evaluation of the cytotoxicity test of the bletilla striata polysaccharide prepared in the embodiment of the present invention. Under a light microscope, fibroblasts attached to the surface of the material. The survival rate of cells in the composite materials containing different specific gravity bletilla striata polysaccharides was comparable to that in the traditional group. These results indicate that bletilla striata polysaccharide has good biocompatibility and can be used in clinical applications.

[0073] Table 1 Antibacterial test results of Bletilla striata polysaccharide

[0074]

[0075] As shown in Table 1, Streptococcus mutans was inoculated into BHI culture medium, and different proportions of Bletilla striata polysaccharide were added to the culture medium, and antibacterial experiments were carried out using traditional glass ionomer. The results showed that the diameters of the inhibition zones of Bletilla striata polysaccharides with different proportions were all larger than those of the control group with traditional glass ionomer (2.92±0.60 mm), indicating that Bletilla striata polysaccharide had an antibacterial effect, and the difference was statistically significant (P<0.05). Moreover, as the proportion of Bletilla striata polysaccharide added increased, the diameter of the inhibition zone became larger. The diameter of the inhibition zone of the sample with a Bletilla striata polysaccharide mass proportion of 7% during preparation was larger than that of pure Bletilla striata polysaccharide, which was 1.25 times that of Bletilla striata polysaccharide and 3.53 times that of the control group, indicating that the sample with a Bletilla striata polysaccharide mass proportion of 7% had a significant inhibitory effect on Streptococcus mutans.

[0076] like Figure 7 As shown in the figure, the cytotoxicity of Bletilla striata polysaccharide on RAW264.7 cells was determined using a CCK8 assay. The results showed that Bletilla striata polysaccharide had no significant direct cytotoxicity below 40 μg / mL, but significantly inhibited the proliferation of RAW264.7 cells at 40 μg / mL. This suggests that the composite bone graft material has a strong anti-inflammatory effect.

[0077] like Figure 8 As shown, RAW264.7 cells were pretreated with 30 μg / mL Bletilla striata polysaccharide for 1 hour and then challenged with 200 ng / mL LPS for 12 hours. Cell culture supernatants were collected and cytokine levels were measured. LPS-induced upregulation of IL-1β, IL-6, MCP-1, and TNF-α cytokines was significantly inhibited by Bletilla striata polysaccharide in a dose-dependent manner. At a concentration of 30 μg / mL, Bletilla striata polysaccharide achieved inhibition rates of 70.74%, 71.04%, 58.28%, and 21.21% for IL-1β, IL-6, MCP-1, and TNF-α, respectively. Therefore, a 30 μg / mL concentration of Bletilla striata polysaccharide was used in subsequent studies. This suggests that Bletilla striata polysaccharide-based composite bone graft material exhibits a potent anti-inflammatory effect.

[0078] like Figure 9 As shown, the composite bone graft material of the present invention is used as the experimental group, and the xenogeneic bone is used as the control group to carry out in vitro experiments. The expression levels of the genes of autologous tooth bone powder DMP-1, ALP, Periostin, OPN of the composite bone graft material are not only higher than those of the control group at all time points, but also more and more higher as time goes by. The expression levels of DSPP, Decorin and OCN remain stable with the control group at 3 days, and begin to rise at a later time point. However, there are no significant differences between the experimental group and the control group in the expression of fibronectin (Fibronectin) and COL-III that are unrelated to mineralization. The osteogenic mineralization ability of the composite bone graft material has been verified by this in vitro experiment.

[0079] like Figure 10 As shown, CR analysis was performed before autologous dental bone powder bone grafting surgery and at 2 weeks and 4 weeks after surgery. It was found that the relative gray value increased steadily over time, the material was slowly absorbed, the bone density increased steadily, the oral soft tissues healed well, and there was no inflammation. It can be seen the bone augmentation at the site where autologous dental bone powder material was implanted (red line): A was immediately after tooth extraction, and there was no residue in the extraction socket; B was 2 weeks after material implantation, and large particle bone powder could be seen in the extraction socket; C was 4 weeks after material implantation, and the large particle bone powder had been absorbed. Relative gray value: A < B < C. It can be seen that autologous dental bone powder has a good effect in repairing oral bone defects.

[0080] As Figure 11 As shown, in the imaging analysis of the longitudinal study of autologous dental bone powder in bone repair of periodontitis patients, LH: height of the lingual crest; BH: height of the buccal crest; CH: height of the central alveolus; PH: height of the palatal crest. A total of 36 bone graft sites were observed, and no obvious inflammatory reactions such as redness, swelling, or exposure of the collagen membrane were found.

[0081] Table 2 Changes in the height of the alveolar bone of the jaws in patients with severe periodontitis

[0082]

[0083] Table 2 lists the alveolar bone heights at the upper and lower jaw tooth extraction sites before and 6 months after surgery. The alveolar bone height at the buccal crest of the upper jaw increased by (2.15 ± 2.90) mm; at the center of the alveolar socket increased by (2.45 ± 2.36) mm; at the palatal crest increased by (1.62 ± 3.19) mm; the height of the buccal crest of the lower jaw increased by (-0.19 ± 3.52) mm, the height at the center of the alveolar socket increased by (0.70 ± 2.71) mm, and the height of the lingual crest increased by (5.07 ± 4.34) mm. There were significant statistical differences in the alveolar bone height on the buccal side of the upper jaw, the central fossa height, and the alveolar bone height on the lingual side of the lower jaw before and after surgery (P < 0.05). This indicates that the composite bone graft material containing autologous dental bone powder also has the potential to effectively restore the bone mass at some sites of the patient's tooth extraction socket.

[0084] As Figure 12 As shown, in the bone graft area after autologous dental bone powder implantation surgery, microscopic observation found that new bone, loose fibrous tissue, and abundant angiogenesis were present in all histological specimens. The autologous dental bone powder material particles were completely mixed with the newly formed bone, indicating that the composite bone graft material containing autologous dental bone powder also has significant benefits for bone augmentation on the buccal surface of the tooth extraction socket and the center of the alveolar socket.

[0085] As Figure 13As shown, the implantation of autologous dental bone powder affects the clinical manifestations, among which A1, B1, and C1 are the coronal and cross-sectional CBCT images before surgery, A is the preoperative 3D model; A2, B2, and C2 are the coronal and cross-sectional CBCT images 6 months after surgery, B is the 3D model 2 years after surgery; A3, B3, and C3 are the coronal and cross-sectional CBCT images 2 years after surgery, and C is the overlapped model before surgery and 2 years after surgery;

[0086] like Figure 14 As shown in the chart, it can be seen that autologous tooth bone powder has a better osteogenesis effect than Bio-Oss bovine bone powder, namely DBBM in the figure.

[0087] In summary, adding a specific proportion of Bletilla striata polysaccharide to the porous structure of autologous tooth bone powder can significantly improve the efficiency of bone regeneration while inhibiting the LPS-induced release of IL-1β, IL-6, MCP-1 and TNF-α to reduce the risk of postoperative infection, ultimately achieving efficient repair of complex bone defects.

[0088] The above is only a further embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes based on the technical solutions and concepts of the present invention within the scope disclosed by the present invention, which fall within the scope of protection of the present invention.

Claims

1. A method for preparing a composite bone transplant material based on Bletilla striata polysaccharide and autologous tooth bone powder, characterized in that the steps include: Step 1: preparing Bletilla striata polysaccharide (BSP) from Bletilla striata; Step 2: After pre-treatment, the extracted tooth is crushed to obtain autologous tooth bone powder (AutoBT); Step 3: dissolving the BSP in water and stirring to obtain a BSP solution; Step 4: pouring the AutoBT into the BSP solution, allowing it to stand and stirring to obtain a BSP-loaded AutoBT solution; Step 5: vacuum drying and ultraviolet sterilization of the BSP-loaded AutoBT solution to obtain a composite bone transplant material.

2. The preparation method according to claim 1, characterized in that In step 1, the preparation process of the BSP specifically includes: Step (1): crushing and sieving the bletilla striata to obtain bletilla striata powder; Step (2): taking the Bletilla striata powder, mixing it with water in a ratio of 1: (20-40) to obtain a mixed solution, extracting the mixed solution at 70-90° C. for 2 h, and repeating the extraction multiple times to obtain an extract; Step (3): filtering the extract, concentrating the filtrate under reduced pressure in a rotary evaporator to obtain a finished product, adding ethanol to the finished product and filtering to obtain a precipitated product; Step (4): dissolving the precipitated product in step (3) in water, deproteinizing and freeze-drying by the Sevag method, dialyzing, adding ethanol to the product, filtering to obtain a BSP precipitated product, and drying and crushing the product to obtain Bletilla striata polysaccharide.

3. The preparation method according to claim 2, characterized in that In step (3) and step (4), the ethanol is 95% by volume and the added amount is 3 times of the solute; the finished product is a thick paste with a water content of 15-20%; and the drying temperature in step (4) is 40-60°C.

4. The preparation method according to claim 1, characterized in that In step 2, the pretreatment of the extracted tooth includes: removing soft tissue and enamel of the extracted tooth by a rapid turbine, extracting the pulp and decayed tooth, retaining the healthy dentin part, blowing the healthy dentin part dry with an air gun until no moisture remains, and sterilizing it by ultraviolet light.

5. The preparation method according to claim 1, characterized in that In step 2, the pulverization is performed using an autologous dental bone grinder, and the particle size of the autologous dental bone powder is 0.5-0.7 mm.

6. The preparation method according to claim 1, characterized in that In step 3, the BSP concentration of the BSP solution is no more than 7%.

7. The preparation method according to claim 1, characterized in that In step 4, the static stirring specifically comprises standing for at least 3 hours, and stirring for one minute every hour.

8. The preparation method according to claim 1, characterized in that In step 5, the vacuum drying is specifically to spread the BSP-loaded AutoBT solution flat on a sterile tray and place it in a vacuum dryer for drying for at least 24 hours; the composite bone graft material is sealed and stored in a sterile environment at -20°C for future use.

9. A composite bone transplant material based on Bletilla striata polysaccharide and autologous tooth bone powder, characterized in that: The method is as described in any one of claims 1 to 8.

10. Use of the composite bone transplant material based on Bletilla striata polysaccharide and autologous tooth bone powder according to claim 9 in the preparation of oral bone defect repair materials.

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