Research On Three-dimensional Printing Technique Faced Alveolar Bone Repair

Periodontal disease is one of the two major diseases in the human mouth,and the incidence of the disease in the population is as high as 80-90%,which is the main cause of tooth loss in adults.Alveolar bone is the main structure of periodontal support tissue,which plays an important role in the occurrence,development and cuteness of the teeth and the daily chewing.Sufficient bone volume in the implant area is a prerequisite for implant insertion,and is a critical factor for ensuring successful dental implantation.The repair of alveolar bone defect caused by severe periodontal disease has become an important part of dental implant surgery.In recent years,with the development of tissue engineering in the field of stomatology,the use of tissue engineering techniques to construct threedimensional porous scaffold is expected to be a new technique for repairing the bone repair.This paper presents a method for the preparation of a personalized porous ?-TCP/collagen scaffold based on 3D bio-printing to repair bone defects in patients.Research first on the research progress and bone tissue engineering scaffold preparation methods are reviewed,summarized the existing alveolar bone repair methods,alveolar bone repair in tissue engineering are discussed in the application and prospect.In combination with the medical image technique,the patient's tooth model was reconstructed and the personalized repair module was designed to match the shape of the alveolar bone.We used the biological 3D printer controlled by the printing parameters developed by our team and combined with alveolar bone structure and function to select ?-TCP and type I collagen as biomaterials for alveolar bone repair scaffolds.We got the process paramenters of the ?-TCP scaffolds in printing,as the folloeing: the solid content of the slurry with 32 vol%,the print nozzle was 0.35 mm conical needle,the thickness of the print layer was 0.28 mm,the filling space was 0.8mm,the extrusion pressure was 1.2-1.8 MPa,the printing speed was 8 mm/s,the temperature of the platform was 37-40?.Analyzing the porosity,porosity,mechanical properties of sintered ?-TCP scaffolds by comparing the filling angles of 0/90 °,0/60 °,0/45 ° and the concentrations of collagen of 0.1 mg / m L,0.25 mg / m L,0.5 mg / m L.Selecting the optimal filling angle 0/90 ° and the optimal coating collagen concentration 0.5mg / m L for sintered ?-TCP scaffold.The three-dimensional shape of the fabricated scaffold was identical to the bone defects modal,simulating the collagen fiber network in natural bone,with multi hole structure,an average macropore diameter of 315 ?m,micropore diameters ranging from 3 to 5?m,and an average porosity of 84%.The mechanical properties of the scaffold was similar to cancellous bone,with the mean compressive strength was 12.29±0.88 MPa and the mean Young's modulus was 116.74±27.75 MPa.In vitro culturing experiments of mouse bone marrow mesenchymal stem cells(m BMSCs)demonstrated that the coated of collagen promoted their bioactive and osteogenic properties,including better cytocompatibility,cell adhesion,proliferation,alkaline phosphatase(ALP)activity,and bone-related gene expressions(Collagen-I,BSP).The results demonstrated that the collagen gel coated ?-TCP scaffolds had the matching shape,good controllable porosity and good osteogenic activity for m BMSCs through 3D printing technique.Successful realization of scaffold fabrication will provides a new technique for repairing alveolar bone defect.