Experimental Study On The Bioactivity And Osteogenesis Of PLLA/DDM Scaffolds

ObjectiveWith the lack of bone mass in the oral implant area and the use of various bone graft materials to promote osteogenesis,there are more and more studies on the promotion of osteogenesis.In particular,the research and application of polylactic acid materials in the field of oral implantation has increasingly become a research hotspot,and polylactic acid and its copolymers It plays an important role in the repair and reconstruction of bone defects.In this experiment,we synthesized a new type of polylactic acid combined with human dental bone matrix porous osteogenic material,and explored the osteogenic effects of the new material through in vivo and in vitro osteogenic experiments.Osteogenic properties.MethodsCollect the extracted teeth in the last week of oral and maxillofacial surgery,remove the pulp,root surface soft tissue and crown enamel,and then perform demineralization and deantigen treatment.After grinding and sieving,use solution casting/particle leaching method and polylactic acid.After fusion,drying and sterilization,the poly(L-lactide)/demineralized dentin matrix(PLLA/DDM)scaffold was obtained.The scaffold was passed through scanning electron microscope(SEM)and energy dispersive spectrometer(EDS),Observe the surface morphology and composition of the material,detect the physical characterization of the material through roughness detection and water contact angle,and observe the weight loss rate and Ph value change of the material through the scaffold degradation experiment.The experiment is divided into 4groups: group A PLLA/DDM stent,group B is pure polylactic acid(PLLA)stent,group C is the demineralized dentin matrix(DDM)particles processed by vacuum ultrasonic treatment of finished reagent,The group Dis a blank control.Detect cell adhesion,proliferation and differentiation,observe the adhesion of mouse embryo osteoblast precursor cells(MC3T3-E1)on the surface of the scaffold material in group A and group B with SEM;take 10 mm Diameter materials were placed in a 24-well plate for co-cultivation with MC3T3-E1 to detect cell proliferation after 1,3,5,and 7 days of culture,and each group of materials and MC3T3-E1 were co-cultured for 3,7,and 14 days to detect alkali Alkaline phosphatase activity(ALP).Twelve New Zealand rabbits were taken,and 4 full-thickness skull defects with a diameter of about 1 cm were prepared on each rabbit’s skull.One hole A was implanted with PLLA/DDM stent,hole B was implanted with PLLA stent,hole C was implanted with DDM particles,The hole D was used as a blank control.Skull defect specimens were taken at 1,3,and 5 months for gross observation,Micro computed tomography(Micro CT),and tissue sections for morphological and histopathological observation.ResultsSEM analysis showed that DDM was evenly distributed in the polylactic acid scaffold and formed a porous scaffold structure.The water contact angle showed that the water absorption of the porous scaffold was improved after DDM powder was added.EDS showed that the scaffold had calcium and phosphorus after adding DDM powder.The peak values of the stents are significantly increased,and the porosity test shows that the scaffold has a higher porosity.The stent degradation experiment showed that the stent gradually degraded with the increase of time,and its Ph value increased slightly.Cell culture and animal model results show that the porous scaffold composed of PLLA/DDM has good biocompatibility and can promote cell proliferation and differentiation.Histological and Micro CT evaluations show that the material exhibits good biocompatibility,biodegradability and osteoconductivity with host bone tissue in vivo.The results show that the PLLA/DDM stent may have significant clinical advantages and has the potential to be used in orthopedic surgery and dental implant surgery.Conclusions1.PLLA/DDM stent has good degradation in vitro,its Ph value is slightly increased and it can neutralize the acidic environment generated during the degradation of PLLA2.The PLLA/DDM scaffold has good biocompatibility in vitro.It can promote the adhesion and proliferation of mouse MC3T3-E1 cells.The PLLA/DDM scaffold has good in vivo biocompatibility and can promote bone defects in rabbit skulls.Repair and reconstruction.3.PLLA/DDM scaffold material can be a potential biological graft material for repairing bone defect area.