148 results about "Osseointegration" patented technology

The invention relates to the technical field of oral implantation guidance, and provides a digital false tooth mounting and positioning device based on three-dimensional scanning and a method thereof. The method comprises the following steps: scanning the oral cavity of a patient through an oral cavity scanner to generate a three-dimensional oral cavity digital model; generating a virtual implant of the patient and corresponding initial implantation parameters based on the three-dimensional oral cavity digital model through a SegFormer segmentation network; based on historical operation data, initial implantation parameters, bone density, patient attributes and occlusal force parameters, a long sequence prediction network is adopted to predict the position offset and bone resorption degree of the virtual implant after osseointegration through a segmented attention mechanism and a network memory cache mechanism, and optimal implantation parameters are obtained; and pushing a visual dynamic model containing the candidate positioning strategy to the user based on the optimal implantation parameter, driving an oral cavity model printer to obtain an implantation guide plate model and an oral cavity environment model, assisting the user in verifying the installation effect of the candidate positioning strategy, and improving the accuracy of false tooth installation and positioning.

The invention discloses a bionic heterogeneous composite structure bone implant and a preparation method thereof, and relates to the technical field of medical implants.The bionic heterogeneous composite structure bone implant comprises an inner-layer cross-shaped structure, a middle-layer negative Poisson's ratio structure and an outer-layer honeycomb structure, and the cross-shaped structure, the negative Poisson's ratio structure and the honeycomb structure jointly form a bionic composite structure; and immersing the bionic composite structure subjected to double-network crosslinking into a drug-containing solution for post-treatment and drug loading to obtain the bionic heterogeneous composite structure. According to the invention, bionic adaptation and intelligent optimization of mechanical properties are realized, and the stress shielding problem is solved; according to the invention, osseointegration and vascularization processes are obviously accelerated and enhanced, and leap-type improvement of biological activity is realized; a novel intelligent treatment mode based on in-vivo microenvironment response is developed, and on-demand and accurate drug delivery is achieved.

The invention provides a mineralized collagen cartilage repair scaffold and a preparation method and application thereof, and relates to the technical field of biomedical materials.The preparation method comprises the steps that a collagen solution subjected to mineralization treatment is injected into a mold, and a mineralized collagen layer is obtained through deep freezing and primary freeze drying; taking the mineralized collagen layer as a bottom layer, injecting a collagen solution which is not mineralized, and performing deep freezing and first freeze drying to obtain a freeze-dried scaffold; and carrying out crosslinking and secondary freeze drying on the freeze-dried scaffold, and compressing to obtain the mineralized collagen cartilage repair scaffold. A necessary bioactive interface, a continuous interpenetrating structure of a collagenous fiber network and cross-linking treatment are provided for osseointegration, and interlayer separation is avoided; bidirectional regeneration of osteochondral bone is realized, and complexity and risk of clinical application are reduced; in a wet state, good tailorability and enough stiffness are achieved, and meanwhile stable mechanical support is provided; the technical problem that in the prior art, a stent material is insufficient in systematicness of biosecurity of multi-scale structure bionics and interface bonding agents is solved.

The invention relates to a time sequence degradable orthopedic implant material which comprises a base material and a biodegradable coating formed on the surface of the base material, the surface of the base material is provided with a nanocone array microstructure, the biodegradable coating takes a biodegradable polymer as a matrix and loads a metal element for promoting bone repair, and the metal element is a metal element for promoting bone repair. And the surface of the biodegradable coating is also connected with an anti-inflammatory active factor. According to the invention, grafted anti-inflammatory active factors are matched with the biodegradable coating loaded with metal elements for promoting bone repair, and the sequential active regulation and control of the biological effect of the micro-morphology on the surface of the base material cope with effector cells in different repair stages; the time sequence regulation and control on the macrophage inflammation phenotype and bone marrow mesenchymal stem cell osteogenic differentiation in different stages of bone repair are realized, so that each stage of bone tissue repair is matched, and bone repair and osseointegration are promoted.

An implant system has an acetabular cup with an interior bearing surface with a central bearing zone that is smooth and devoid of holes or indentations. The cup also has a peripheral bearing zone that contains insertion tool engagement holes. The engagement holes are only present in the peripheral zone and have specific shapes and dimensions. The system includes an insertion tool with retractable interlocks that fit within the engagement holes to position the cup during implantation. The central bearing zone bears the main forces during articulation, while the peripheral zone withstands minor forces. The location of the engagement holes has a negligible effect on the cup's performance. The cup can be made of ceramic and may have a coated exterior surface for osseointegration.

A three-dimensional (“3D”) printed orthopedic fixation implant can reduce stress shielding and / or enhance osseointegration. The implant can include: a head defining a proximal end of the implant; a tip defining a distal end of the implant; a core extending from the head to the tip, the core being elongate; and threads extending along at least a portion of the core. One or more functionally graded lattice structures can be propagated longitudinally and / or radially in at least portions of the core. A density of the one or more functionally graded lattice structures can have a varying longitudinal gradient and a varying radial gradient.

This invention relates to the field of biomedical technology, specifically to a biomimetic piezoelectric scaffold for promoting bone repair, its preparation method, and its applications. The biomimetic piezoelectric scaffold provided by this invention is produced by electrospinning PLLA into oriented nanofibers, and then modifying the fiber surface with nano-hydroxyapatite. To enhance the adhesion of hydroxyapatite to the fiber surface, a polydopamine layer is modified between the two as a connecting layer, ultimately resulting in a biomimetic piezoelectric scaffold with high porosity, good osteointegration, and osteogenic promoting effects. This scaffold exhibits good bone regeneration promoting effects in in vitro MSC recruitment, osteogenic differentiation experiments, and repair of skull bone defects in rats.

The invention provides hydrogel, a porous titanium / hydrogel composite implant material and a preparation method of the porous titanium / hydrogel composite implant material. The hydrogel is obtained by photo-crosslinking and curing a hydrogel precursor solution containing acrylated beta-cyclodextrin, acrylated alendronate sodium, gelatin and a chemotactic factor. The hydrogel has a porous network structure, high elastic modulus, high fatigue resistance and excellent biocompatibility, and also has the capability of recruiting bone marrow mesenchymal stem cells (BMSCs) and the capability of promoting osteogenic differentiation of the BMSCs; the porous titanium / hydrogel composite implant material prepared from the hydrogel can effectively promote the growth of new bone tissues, has excellent osseointegration capability, obviously improves the osteogenesis repair effect and the osseointegration effect, provides a new treatment approach for the repair treatment of segmental bone defects, and has important medical significance.

The present application belongs to the field of biomedical materials and computer aided design technology, and discloses a kind of porosity gradient adjustable hip joint prosthesis porous coating topological optimization method.The present application is aimed at solving the problems of existing design, such as unadjustable porosity distribution, gradient mutation, difficult to balance mechanical properties and bone integration, and the gap between topological optimization and manufacturing constraints.The method introduces nonlinear porosity gradient constraints and adaptive optimization mechanism in the process of topological optimization through the steps of geometric modeling and boundary condition definition, nonlinear porosity gradient field generation, finite element analysis, sensitivity analysis, density filtering and porosity constraint processing, optimization criterion updating and convergence judgment, and realizes the smooth transition of porosity from the core to the surface of the prosthesis.The present application can optimize the mechanical support and biological integration performance simultaneously, eliminate non-manufacturable structures, and adjust the gradient parameters and modularize the extension, providing an efficient and reliable calculation method for personalized hip joint prosthesis design, and having significant engineering and clinical application value.

The invention discloses a titanium metal dental implant and a processing method thereof, and belongs to the technical field of medical instruments, the surface of an implant part of the implant is provided with a composite bioactive layer, and the composite bioactive layer is formed by compounding a first-stage micron hole layer formed by selective laser micro-melting and a second-stage submicron-nano mesh hole layer formed by micro-arc oxidation, and the secondary pore layer has gradient distribution of bioactive elements such as calcium and phosphorus. The processing method comprises the steps of matrix pretreatment, construction of a micron structure through selective laser micro-melting, synchronous construction of a nano structure through micro-arc oxidation, element gradient doping and post-treatment. The surface of the prepared implant has a unique micron-nano graded composite pore structure and gradient distribution of bioactive elements, the mechanical stability and the biological activity of the implant can be synergistically promoted, rapid and stable osseointegration is realized, the processing method is green and controllable, and the implant has a good application prospect.

A cervical fusion implant with serrations and radio opaque marking and a method thereof is disclosed The cervical fusion implant is optimized for enhanced spinal stabilization and integration. The cervical spine fusion implant is constructed from polyether ether ketone, known for its exceptional durability and biocompatibility. The implant is designed with a robust body encased in a protective capsule. The design ensures superior structural integrity and functional utility. The implant incorporates a self-stabilizing screw assembly featuring at least four lateral surfaces, each with slits to promote bone growth and integration. Additionally, the anterior surface is equipped with a screw hole for secure fixation using a titanium screw. This combination of features aims to improve spinal stabilization, promote effective fusion, and ensure long-term implant performance. Furthermore, the implants assist to maintain normal cervical curvature of the patient.

The application relates to a three-dimensional adjustable bone-integrated half-pelvis prosthesis, which comprises a split assembled customized sacrum bone-integrated base, an acetabular cup assembly, a customized pubic bone-integrated base, a sacrum side pelvis ring support assembly and a pubic side pelvis ring support assembly; one end of the customized sacrum bone-integrated base is connected with the sacrum, and the other end is connected with the acetabular cup assembly through the sacrum side pelvis ring support assembly; one end of the customized pubic bone-integrated base is connected with the healthy pubic bone, and the other end is connected with the acetabular cup assembly through the pubic side pelvis ring support assembly; when the acetabular cup assembly, the sacrum side pelvis ring support assembly and the pubic side pelvis ring support assembly are assembled, the anteversion angle of the acetabular cup assembly can be adjusted relative to the sacrum side pelvis ring support assembly and the pubic side pelvis ring support assembly. The half-pelvis prosthesis and the pelvis of the patient constitute a complete and stable pelvis ring structure, the stability of the half-pelvis prosthesis is improved, and the accuracy and convenience of the prosthesis installation during the operation are greatly improved.

The invention discloses a preparation method of a nano copper selenide antibacterial peptide-loaded multistage microporous titanium alloy. The preparation method comprises the following steps: 1, preparing a substrate; 2, surface modification; and 3, carrying out functionalization treatment to obtain the multistage microporous titanium alloy loaded with the nano copper selenide antibacterial peptide. The invention further provides the multistage microporous titanium alloy loaded with the nano copper selenide antibacterial peptide. The load design and photo-thermal synergistic mechanism of the nano copper selenide antibacterial peptide-loaded multistage microporous titanium alloy can effectively inhibit bacterial breeding and greatly reduce the infection risk of implantation operations, and on the aspect of promoting osseointegration, the multi-scale structure and ion slow release design can accelerate bone tissue growth and material fusion and reduce long-term complications, so that the titanium alloy can be used as a medical material for treating osteoporosis. The bone repair microenvironment is optimized, a new thought, good stability and safety are developed for complex disease treatment, long-term stable effect in vivo is guaranteed, strict standards are met, a solid foundation is laid for large-scale clinical application, and the bone implantation medical field is expected to be innovated.

The invention relates to the field of medical instruments, and provides a conicity-locked osseointegration prosthesis. The osseointegration prosthesis comprises an implantation prosthesis, a percutaneous device and an abutment screw, a plurality of fixing ridges are arranged on the periphery of the implantation prosthesis, intraosseous fixation is achieved in a press-fit mode, a taper locking structure is combined to prevent the implantation prosthesis from sinking, and it is ensured that the position of the implantation prosthesis is fixed after implantation; a flushing hole communicated with the internal flushing cavity is further formed in the periphery of the implant prosthesis, and the implant prosthesis can be used for injecting medicine into the medullary cavity, implanting bone materials and the like or used for follow-up flushing treatment for intramedullary infection possibly occurring in the later period. The percutaneous device and the implanted prosthesis are connected through the anti-rotation structure and the taper locking structure, the percutaneous section has the surface state formed through surface treatment, stimulation to surrounding soft tissue is reduced, the anti-infection capacity is improved, and the percutaneous sealing effect is improved. By optimizing the implantation structure and the percutaneous interface design, the intraoperative operation difficulty is reduced, the intraoperative time is shortened, meanwhile, the percutaneous stoma is reduced, and the infection risk is reduced.

The utility model relates to the intervertebral fusion cage technical field discloses a kind of anti-drop intervertebral fusion cage. To solve the stress shielding problem in the actual use of conventional intervertebral fusion cage in prior art, and porosity is lower, fusion rate is low after operation;Lack of bone integration channel, the technical problem of low fusion rate after operation. The utility model includes support frame, at least two bone graft channels are arranged on support frame, to fill bone induction material and promote bone growth;Support frame end is provided with clamping groove;Support frame includes edge support part, and edge support part is connected by porous structure between;The porosity of porous structure gradually changes from small to large by the direction close to far from vertebral body, and presents gradient distribution. The utility model effectively balances the problem of insufficient porous structure strength, and the problem of too large solid structure quality, and the porosity of porous structure is large, has more bone integration channel, is conducive to the growth of bone cell, and can effectively improve bone growth rate.

The application discloses a bone-integrative degradable silica gel support for treating bone nonunion and a preparation method thereof, and relates to the technical field of medical implant materials.The preparation method comprises the following steps: hydrogen-containing silicone oil and allyl glycidyl ether are subjected to a hydrosilylation reaction under the action of a platinum catalyst to generate silicone oil containing an epoxy group, then the epoxy group is subjected to ring-opening under the action of a catalyst to obtain silicone oil containing a phosphate group in a side chain; carboxyl-terminated polylactic acid-glycolic acid copolymer is mixed with the silicone oil containing the phosphate group in the side chain, and a condensation reaction is carried out under the action of a condensing agent and a catalyst to obtain a PLGA-P-PDMS-PLGA triblock copolymer; the triblock copolymer, a reactive diluent, a photoinitiator and inorganic reinforcing fillers are mixed to obtain 3D printing slurry; and the printing slurry is printed into a designed bone-integrative support according to set printing parameters by using a light-curing 3D printing technology.The application endows the material with intrinsic osteogenic activity, and realizes the unification of bioactivity, shape memory function and mechanical support.

The present invention relates to a torque connector device for an osseointegration prosthetic limb (OPL) system. The device features a body with a base portion that anchors and restrains movement, and includes a first spindle bushing positioned between the base and spindle release body to facilitate axial rotation. A second spindle bushing prevents unwanted pivoting of the first bushing. The spindle release body is centrally aligned to lock rotational alignment and connect the abutment assembly. A threaded connection between the base portion, calibration cap, and washers creates a locked state under normal conditions, maintaining stability across all axes. When torque exceeds a predetermined threshold, the first and second washers deform, disengaging the release pad and spindle release body, and allowing rotational movement to an unlocked state.

The invention particularly discloses immunoregulation type bone biological glue as well as a preparation method and application thereof, and relates to the technical field of bone biological glue. The invention provides an immunoregulation type bone biological glue which can regulate polarization, osteogenesis and angiogenic differentiation of macrophages, and further meets the clinical requirements of the bone biological glue for regulating an implant bone surface and interface immune microenvironment and osseointegration.

The invention belongs to the technical field of medical prosthetic materials, and particularly relates to a zirconia-based medical prosthetic material and a preparation method and application thereof.The preparation method comprises the steps that S1, pretreatment is conducted, specifically, a zirconia preform is subjected to primary high-temperature sintering, then grinding, polishing and primary cleaning are conducted, and then secondary high-temperature sintering and secondary cleaning are conducted; s2, preparation of a surface drug-loading structure: preparing a drug-loading honeycomb porous nano-structure on the surface of the zirconium oxide preform by adopting phosphorylation treatment; s3, loading of metal ions: putting the zirconium oxide material into loading liquid containing the metal ions, reacting in a shaking table at 50-90 DEG C for 5-8 hours, taking out after the reaction is finished, washing and drying to obtain the zirconium oxide-based medical prosthesis material, and drying the zirconium oxide-based medical prosthesis material to obtain the zirconium oxide-based medical prosthesis material. The zirconia-based medical prosthetic material provided by the invention not only avoids the problems of poor wear resistance of PLGA, poor combination of a calcium phosphate coating and color of a dopamine coating, but also realizes slow release of metal ions, thereby promoting osseointegration more effectively.

An intraosseous screw implant pertains to medical equipment. The device is made with a variable height of the single-thread profile (2). Within the full turns (8) of the screw line, projections (7) with an increased height of the thread profile (2) are localized. The projections (7) are intended to bear the immediate load of the orthopedic structure. The projections (7) are located on adjacent turns (8) and are mutually offset by an angle. In an alternative embodiment of the device, the projections (7) are located from each other through a turn (8). The method for installing the implant includes forming a bone bed in the form of a narrowing opening. The dimensions of the opening are selected based on the condition of free accommodation of the predominant part of the implant. The implant is inserted into the cavity of the bed with the projections (7) resting on the spongy bone layer. Then the implant is screwed into the bone with several turns for fixation. The shape of the implant is optimized based on the condition of intensification of osseointegration of the immediately loaded implant. Reduced traumatic effect of implant screw elements on bone while ensuring immediate biomechanical load. Compacted bone tissue particles in the chip groove (4) at the top of the implant. Increased reliability of osseointegration. Increased implant survival level.

The present discussion relates to the design fabrication and use of synthetic scaffold structure for bone growth. In certain implementations the scaffold structures are comprised of a plurality of repeating structures each defined by a local topology. The local topologies are defined at a subset of points in their respective volumes by various parameters including, but not limited to, shape index, curvedness, mean curvature, and Gauss curvature.

This invention belongs to the field of foot and ankle joint replacement implant technology, and discloses an ankle joint talus prosthesis with an antibacterial porous interface and its preparation method. It includes a prosthesis substrate with an overall anatomically contoured structure, including a superior articular surface, a inferior articular surface, and an anterior articular surface; the area of ​​the prosthesis substrate in contact with residual bone tissue is designed as a three-dimensional porous structure; an antibacterial bioactive composite coating is grown in situ on the surface of the prosthesis substrate; it includes calcium and phosphorus bioactive components and antibacterial ions. This invention, by constructing an antibacterial bioactive composite coating at a porous bone integration interface, utilizes biocompatibility and osteoconductivity to induce bone tissue growth. Furthermore, the antibacterial ions can be slowly and continuously released in the interstitial spaces, achieving a dual function of promoting bone integration and preventing infection. Moreover, the antibacterial bioactive composite coating is formed through in-situ growth, resulting in a strong bond with the substrate and preventing detachment.

The invention provides a preparation method of dynamic connection bone extracellular matrix simulation hydrogel and application of the dynamic connection bone extracellular matrix simulation hydrogel in bone defect repair, and belongs to the technical field of medical hydrogel. L-cysteine ethyl ester functionalized hyaluronic acid and allicin are prepared to form a thiol-disulfide bond dynamic cross-linked network; a sacrificial pre-vascularization template is constructed by combining a collagen thread loaded with a vascular endothelial growth factor, a vascularization guide microchannel is formed by utilizing the enzymolysis characteristic of collagen, the polarization of macrophages is regulated and controlled by hyaluronic acid to inhibit inflammatory response, and the adhesion and osteogenic differentiation of mesenchymal stem cells are promoted by virtue of a functional surface, so that the osteogenic differentiation of the mesenchymal stem cells is promoted. The synergistic effect of vascularization, anti-inflammation and osseointegration is achieved, finally, the dynamic connection bone extracellular matrix simulation hydrogel with a porous interconnection structure and biological activity is formed, and the technical problems that a traditional bone defect repair material is insufficient in vascularization, inflammation interference exists, and osseointegration is poor are solved.

The present application relates to a kind of biomimetic reticular nanofiber composite coating and its preparation method and infectious bone defect repair application, belong to biomedical material field.The present application is aimed at solving the technical problem of the poor bone integration of implant in infectious bone defect.The present application provides a kind of biomimetic reticular nanofiber composite coating, which is formed by layer-by-layer self-assembly on the surface of implant by lysozyme amyloid fiber and polyphenols (such as tannin etc.) Form reticular structure, then prepared with bioactive metal ions coordination;The number of coating layers is 4-8 layers.Preparation method includes lysozyme fiberization, alternate deposition and ion loading steps.The composite coating of the present application has broad-spectrum antibacterial, antioxidant stress and promotes osteogenesis function;In animal model, bacterial load is reduced by 80%, bone volume fraction and trabecular bone parameters are significantly improved, and can realize anti-bacterial biofilm infection-antioxidant stress-angiogenesis-promote bone regeneration synergy.

A pedicle replacement device is designed to both replace the pedicle through osseointegration and protect the nerves and surrounding tissue from injury by pedicle screws or other surgical devices and instruments. The implant is configured to shield a fixture, reduce nerve root irritation, and diminish loosening of the fixture, when the fixture is implanted into the void of a target site. The implant includes features for stabilizing and securing the implant within the void at the target site. For example, in one embodiment, the implant includes counterclockwise threads that stabilize the implant against rotational and extractive forces that could disturb the implant.

An intraosseous dental implant for the application of biologically active agents directly to the surrounding soft tissues and bone tissue, and their substitutes, is described. The implant enables the measurement of the newly formed or lost bone tissue volume immediately adjacent to the implant. Increasing the dynamics of osseointegration growth directly results in the possibility of reducing the duration of the entire treatment protocol. To increase dynamics of the osseointegration process, the type of material from which the implant is made, its design features, surface topography, as well as the formation of layered structures and coating applications, are described. The implant introduces growth factors and other biologically active factors that affect an increase in the dynamics of osseointegration strength. The entire implant or a porous section thereof can be produced by 3D printing through selective melting / sintering of biocompatible metallic, ceramic, or metallic-ceramic composite powders with laser or electron beams.

The present application belongs to the technical field of surgical implant medical devices for foot and ankle, and discloses a preset angle ankle arthrodesis device with functions of promoting bone integration and resisting bacteria, which has a preset angle suitable for tibiodal joint, ranging from 3° to 7°. The device further comprises a three-dimensional porous bone implant body, a surface of the three-dimensional porous bone implant body in contact with host bone tissue is a porous titanium alloy, a plurality of convex anti-rotation ridges are arranged on the upper and lower end faces of the three-dimensional porous bone implant body, the three-dimensional porous bone implant body is fixed by occlusion with the host bone through the anti-rotation ridges, an in-situ growth film layer is grown on the surface of the three-dimensional porous bone implant body, and the in-situ growth film layer comprises functional substances and antibacterial substances. The present application effectively solves the technical problems of slow bone integration, high risk of infection, rotation instability and insufficient mechanical support in ankle arthrodesis, significantly improves the success rate of fusion and reduces postoperative complications.

The invention provides a novel biodegradable magnesium-hydroxyapatite-graphene biological material system for an advanced orthopedic implant, and relates to the technical field of implants, and the novel biodegradable magnesium-hydroxyapatite-graphene biological material system for the advanced orthopedic implant comprises magnesium, hydroxyapatite and a graphene nanosheet. Hydroxyapatite and graphene nanosheets are uniformly distributed in a magnesium matrix, and the mechanical property is very close to that of a human skeleton; the mechanical adaptation of magnesium is combined with the osseointegration performance of hydroxyapatite and the strengthening and corrosion resistance of the graphene nanosheets, the orthopedic implant is naturally integrated in vivo and can be gradually decomposed and completely degraded in vivo, the problem that traditional non-degradable materials (such as titanium or stainless steel) need to be taken out through a secondary operation is solved, the graphene nanosheets inhibit pitting corrosion, and the mechanical property of the orthopedic implant is improved. The corrosion rate is reduced by about 50%, the orthopedic implant has corrosion resistance, the service life of the implant is prolonged, and hydroxyapatite promotes bone growth and accelerates bone healing.

The invention belongs to the technical field of medical instruments, and relates to a self-stabilizing fusion cage with titanium end plates, the self-stabilizing fusion cage comprises a fusion cage body and anchoring elements arranged on the upper side and the lower side of the fusion cage body, the fusion cage body comprises two titanium end plate layers which are symmetrically arranged up and down, and a PEEK center layer which is cooperatively connected between the two titanium end plate layers, a mounting hole matched with the anchoring element is formed in the right end of the fusion cage body, the anchoring element obliquely extends towards the upper side or the lower side of the fusion cage body through the mounting hole, and a limiting piece matched with the right end of the anchoring element is arranged in the mounting hole and used for preventing the anchoring element from moving left and right after being mounted in place. According to the invention, osseointegration with bones can be realized, vertebral fusion is facilitated, and the vertebral fusion condition can be observed through imaging after an operation; meanwhile, better holding force can be obtained, and the fusion effect is further improved.

Disclosed are a dental implant and an antibacterial coating method for a titanium substrate, the dental implant comprising: a titanium substrate; and a coating layer formed on at least a portion of the surface of the titanium substrate and comprising a silver-apatite complex, wherein the Ag / Ca molar ratio of the coating layer is 0.3 to 0.6, and the Ca / P molar ratio is 0.9 to 1.1.