| ObjectivesTrauma,tumor,inflammation,congenital malformation,tooth extraction and other causes can cause oral and maxillofacial bone defects or bone deficiency.Only using artificial bone materials to repair bone defects often can not achieve the desired effect.Therefore,this study hopes to improve the osteogenic effect of bone repair materials by using bioactive ions or proteins.However,there are different bone defect situations.In this study,an injectable bone cement with active strontium ion was constructed for the treatment of irregular bone defect in oral and maxillofacial cavities,in order to highly match bone defect site and rapid guide bone regeneration with minimally invasive treatment.For the large-size massive bone defect of oral and maxillofacial region,this study attempted to load bioactive protein-irisin on the composite scaffold of silk protein to further improve the ability of bone repair.These two methods provide a new idea for the clinical treatment of oral and maxillofacial bone defects or bone deficiency in different situations.Material and Methods1.For the cavity-type irregular bone defect,a strontium-doped hardystonite phosphate cement was constructed,and its physical and chemical properties were tested by X-ray diffraction,injectability,cohesiveness,setting time,exothermic behaviour,microstructure and radiatiopacity,mechanical properties,degradation,p H value and other experiments.The biocompatibility was tested by cell proliferation assay.The osteogenic properties in vivo were observed by maxillary sinus elevation experiment.2.For large-size massive bone defects,a silk fibroin porous composite scaffold loaded with irisin was constructed.Expansion coefficient,degradability,stress and strain,p H experiments were used to observe physico-chemical properties of the scaffold material.Through testing of irisin in vitro release behavior and biological detection experiments to observe the osteogenesis ability of silk fibroin composite scaffold loaded irisin in vitro.And the in vivo osteogenesis performance was determined through the in vivo experiment.Results1.Injectable strontium-doped hardystonite phosphate cement has good injectability and operability,and its compressive strength is similar to that of bone trabecula.The system showed setting temperature below 37 ℃,high radiopacity,close to physiological p H and show good cell compatibility.Compared with calcium phosphate cement commonly used in clinic,it has similar osteogenic properties in vivo.2.Silk fibroin composite scaffold loaded with irisin was immersed in PBS for 28 days and degraded by about 50%,with a stable p H value of 7.2,which was suitable for cell growth.In vitro experiments showed that the irisin released by irisin could promote the osteogenic differentiation of bone marrow mesenchymal stem cells due to its biological activity.More bone regeneration was induced after 8 weeks in vivo.ConclusionsThe injectable strontium-doped hardystonite phosphate cement can effectively repair the cavity-type irregular bone defect.Irisin-loaded porous silk fibrin composite scaffold can promote the repair of large-size massive bone defects.To sum up,this study can effectively promote bone regeneration by adding bioactive ions or proteins.It is expected to provide new ideas for bone defect repair in different situations. |
