Osteogenic Role Of Bone Substitute For Maxillary Sinus Augmentation And Simultaneous Implantation

Objective: To explore whether bone substitute should be implanted in maxillary sinus lift with simultaneous dental implantation,and to compare the effect of blood clot,Van/DFO/Dex liposome-hydrogel complex and bone allograft on bone regeneration.Methods: DFO/Dex liposomes were fabricated by a thin film dispersion method,and mixed with Van sodium alginate solution to form Van/DFO/Dex liposome-hydrogel composite under the action of calcium ions.The microstructure of Van/DFO/Dex liposome-hydrogel composites were evaluated by scanning electron microscopy(SEM).Twelve New Zealand white rabbits(3-month,male,2-2.5kg)were used for maxillary sinus augmentation and simultaneous implantation,and 24 maxillary sinuses in 12 rabbits were randomly divided into four groups(n=6 per group): blood clot group,blank liposome-hydrogel group,medicine loaded liposome-hydrogel group and bone allograft group.After 3 months,rabbits were killed by carbon dioxide asphyxiation method,and all livers were taken out for HE staining to evaluate the biocompatibility of medicine loaded liposome-hydrogel and bone allograft in vivo.All maxillary sinus samples were entirely taken and the effects of different bone substitutes on promoting bone regeneration were evaluated by micro-CT,HE staining,Masson staining,immunohistochemistry(IHC),and HE staining of bone tissue grinding slices.Results: An injection Van/DFO/Dex liposome-hydrogel composite was successfully constructed.SEM showed that the Van/DFO/Dex liposome-hydrogel composite has porous structure.HE staining of rabbits’ livers showed that these organs were no significant difference between the rabbits treated with medicine loaded liposome-hydrogel and bone allograft and normal rabbits.The structures of hepatic lobules are clearly visible,without structural disorder,island-like nodules or new connective tissue,and no diffuse cellular degeneration and necrosis.Micro-CT displayed that in 4 groups,the implants bone union were good,and there were more high density images in maxillary sinuses in medicine loaded liposome-hydrogel group and bone allograft group.HE staining and Masson staining displayed that there were different degrees of new bone formation around the implants in 4 groups.Compared with blood clot group and blank liposome-hydrogel group,more new bone formation was observed in medicine loaded liposome-hydrogel group and bone allograft group.Moreover,compared to bone allograft group,more new blood vessels were observed in bone matrix in medicine loaded liposome-hydrogel group.In IHC the expression of angiogenesis indexes in medicine loaded liposome-hydrogel group was highest in 4 groups.The expression of osteogenic indexes in medicine loaded liposome-hydrogel group and bone allograft group was higher than others.HE staining of bone tissue grinding slices showed that the osseointegration of the implants in the four groups was good.The medicine loaded liposome-hydrogel group had more bone surrounding the implants than the other groups.Conclusion: If the elevation of the sinus mucosa can be maintained during the elevation of the maxillary sinus floor,blood clots in the sinus cavity can also guide bone formation.Using bone substitute in maxillary sinus augmentation surgeries and simultaneous implantation can not only maintain the height of maxillary sinus mucosa,but also improve the efficiency of osteogenesis.Compared to bone allograft,Van/DFO/Dex liposome-hydrogel with injectability is more suitable for irregular bone defect by minimally invasive filling.Van/DFO/Dex liposome-hydrogel effectively promotes angiogenic bone regeneration by steady drug release.