| The commonly used bone graft materials,such as autogenous bone materials,allogeneic bone materials and xenogeneic bone materials,have limitations in supply shortages,immune rejection,cross infection and so on.Therefore,more and more researchers devote themselves to artificial bone repair materials,trying to achieve better osteogenic effects.As one of the most applied artificial materials,bioceramic granules have developed rapidly in the field of regenerative medicine due to their unique biological activity,osteoconductivity and osteostimulation.However,it still remains a great challenge to match scaffolds’ biodegradation with the natural bone’s healing timescale,which indeed puts forward a crucial problem of spatiotemporally controlling pore network evolution and the body osteogenesis response to the bioactive ion stimulations.Here,we described a new-type strategy for preparation of biphasic bioceramic granules with adjustable composition distribution and microporous network via coaxial bilayer capillary system.Granules with β-TCP and Mg-doped β-CaSiO3 slurries as main components were successfully fabricated as follows:mechanical mixing monolayer granules,β-TCP core-Mg-doped β-CaSiO3 shell bilayer granules.Besides,by pre-mixing porogens(PS microspheres,5μm in diameter)into the β-CaSiO3 slurries to confirm accurate shell pore-forming,shell porous core-shell granules were acquired.These three granules can well maintain the spherical form even after the low and high heat treatments.Among them,the mechanical mixed granules had a continuous cross section while the core-shell granules had obvious core-shell boundary.In vitro immersion experiments showed that the degradation rate of mechanical mixed granules are the fastest,and porous core-shell granules are slightly faster than normal core-shell granules in biodegradability.Also,all of them have good remineralization abilities in vitro.In order to evaluate the influences on their degradation behavior and osteogenesis when implanting granules in vivo,granules are implanted into the critical alveolar bone defect models of New Zealand white rabbits,with Bio-Oss used as positive control.At 2,4,8,16 weeks after the operation,alveolar bone species are harvested and measured by micro-CT reconstructed images,histological section staining and quantitative analysis.The results and quantitative analysis show that the Bio-Oss group has a relative lower biodegradation and residuals remain more than 25%at 16 weeks after operation,but the porous internal structure is good for the new bone ingrowth,leading to a pretty good osteogenesis effect.In contrast,the mechanical mixing group has a totally different degradation behavior and remains only 7%residuals at 16 weeks,whose overfast degradation results in a failure of bone repair.As for 2 core-shell granule groups,they exhibit relatively satisfactory osteogenesis.Specially,the core-shell granules with porous shell structure,whose residuals presented 35%,23%,18%and 13%during the observation period of 2-16 weeks,show a stable degradation,thus contributing to new bone ingrowth and healing.After 16 weeks,the new bone volume is up to 40%,also,and the trabeculae number reached to 2.2/mm,indicating the bone tissues turn mature.Above all,such granules packed scaffolds with dynamic degradation highly contribute to bone stimulation effects in New Zealand rabbits’ critical alveolar bone defect,which provides a new clue for the design on bone repair materials and predicts the bright prospects of scalable shape-controlled fabrication protocol in the clinical bone repair.Objective:To observe and evaluate the clinical effects of 3 cases of periodontitis with anterior tooth loss after basic periodontal therapy and dental implant,and to provide some clinical guidance for developing implant treatments for patients with periodontitis.Methods:A total of 3 cases of periodontitis with anterior tooth loss were chosen for this study.All 3 patients accepted basic periodontal therapy and regular periodontal maintenance.Before the surgery,the condition of periodontal inflammation were examined by probing and the amount of bone tissue in the implant areas was evaluate via CBCT,based on which the oral implanting plans were initially established.Bone grafts and guided bone regeneration were used to solve bone defects.After several months of oral implantation,upper dentures were made according to every patients’situation.Oral optical graphs,X-ray films or periodontal probing records were used to evaluate the effect of implant repair and infection control.Results:3 cases all achieved significant improved periodontal condition after basic periodontal treatments,bone incremental surgeries,oral implantation and regular periodontal maintenance.All implants were presented retained,no loosening,and no obvious inflammation of surrounding soft tissues during the observation period.The patients were satisfied with the aesthetic and functional effects.Conclusion:With comprehensive periodontal basic treatments,standard implantation design and regular periodontal maintenance,patients with periodontitis could reached good clinical results in anterior teeth missing,which suggested that comprehensive periodontal treatments and incremental bone surgeries were crucial to successful oral implantation. |
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