ABSTRACT
BACKGROUND@#Teeth can be used as a raw material for preparing bone substitutes due to their similar chemical composition to bone. The objective of our study was to evaluate the effect of odontogenic biphasic calcium phosphate (BCP) incorporating dentin noncollagenous proteins (DNCPs) on osteogenesis and stability in maxillary sinus augmentation. @*METHODS@#The composition, structure and morphology of the odontogenic BCP were tested by X-ray powder diffraction (XRD), Brunauer–Emmett–Teller, and scanning electron microscopy methods. The biocompatibility and osteoinduction of DNCPs and materials were examined in vitro and their bone regeneration capacity was verified in vivo. @*RESULTS@#The results showed that the cells adhered and proliferated well on the DNCP-loaded BCP scaffold. The odontogenic BCP and DNCPs promoted osteogenic differentiation of cells, The new bone formation in the BCP groups and DNCP subgroups was significantly higher than the new bone formation in the control, and the new bone quality was better.The bone regeneration effect of odontogenic BCP was similar to the effect of deproteinized bovine bone mineral, but b-TCP did not maintain the height and volume of bone reconstruction. @*CONCLUSION@#In conclusion, the combined application of DNCPs and odontogenic BCP is an effective strategy for tissue engineering osteogenesis in the maxillary sinus region. The biomimetic strategy could provide a new approach for patients requiring maxillary sinus lifting.
ABSTRACT
BACKGROUND@#Beta-tricalcium phosphate ( β-TCP) has been employed successfully as a synthetic graft material in maxillary sinus floor augmentation (MSFA) for placing dental implants. However, the lack of osteogenic and osteoinductive properties of this substitute invariably results in bone regeneration of low quality and quantity. The purpose of this study was to determine whether loading dentin matrix protein-1 (DMP1) gene-modified bone marrow mesenchymal stem cells (BMSCs) onto β-TCP promoted bone regeneration and osteointegration of dental implants in MSFA of dogs. @*METHODS@#BMSCs were transduced with a lentiviral vector overexpressing the DMP1 gene (Lenti-DMP1) and with a lentiviral vector overexpressing enhanced green fluorescent protein (Lenti-EGFP) in vitro and were loaded into β-TCP scaffolds for autologous sinus grafting. Beagles received bilateral MSFA with four biomaterials (① Lenti-DMP1-transduced BMSCs/β-TCP, ② Lenti-EGFP-transduced BMSCs/β-TCP, ③ BMSCs/β-TCP, ④ β-TCP) and simultaneous implant placement at each sinus. Twelve weeks post operation, the maxillae were explanted, and every sinus was evaluated by radiographic observation, micro-CT and histological analysis. The osteogenic outcomes of bone regeneration and osseointegration were compared between the four groups. @*RESULTS@#The sinuses grafted with Lenti-DMP1-transduced BMSCs/β-TCP constructs presented a significantly higher increase in compact radiopaque area, higher local bone mineral densities, greater bone-implant contact and greater bone density when compared to other three groups. @*CONCLUSION@#These results demonstrated that combinations of β-TCP and DMP1 gene-modified BMSCs could be used to construct tissue-engineered bone to enhance mineralization of the regenerated bone and osseointegration of dental implants in MSFA.
ABSTRACT
BACKGROUND@#Beta-tricalcium phosphate ( β-TCP) has been employed successfully as a synthetic graft material in maxillary sinus floor augmentation (MSFA) for placing dental implants. However, the lack of osteogenic and osteoinductive properties of this substitute invariably results in bone regeneration of low quality and quantity. The purpose of this study was to determine whether loading dentin matrix protein-1 (DMP1) gene-modified bone marrow mesenchymal stem cells (BMSCs) onto β-TCP promoted bone regeneration and osteointegration of dental implants in MSFA of dogs. @*METHODS@#BMSCs were transduced with a lentiviral vector overexpressing the DMP1 gene (Lenti-DMP1) and with a lentiviral vector overexpressing enhanced green fluorescent protein (Lenti-EGFP) in vitro and were loaded into β-TCP scaffolds for autologous sinus grafting. Beagles received bilateral MSFA with four biomaterials (① Lenti-DMP1-transduced BMSCs/β-TCP, ② Lenti-EGFP-transduced BMSCs/β-TCP, ③ BMSCs/β-TCP, ④ β-TCP) and simultaneous implant placement at each sinus. Twelve weeks post operation, the maxillae were explanted, and every sinus was evaluated by radiographic observation, micro-CT and histological analysis. The osteogenic outcomes of bone regeneration and osseointegration were compared between the four groups. @*RESULTS@#The sinuses grafted with Lenti-DMP1-transduced BMSCs/β-TCP constructs presented a significantly higher increase in compact radiopaque area, higher local bone mineral densities, greater bone-implant contact and greater bone density when compared to other three groups. @*CONCLUSION@#These results demonstrated that combinations of β-TCP and DMP1 gene-modified BMSCs could be used to construct tissue-engineered bone to enhance mineralization of the regenerated bone and osseointegration of dental implants in MSFA.
ABSTRACT
As an important sub-discipline of dentistry,orthodontics is regarded as the post-graduate education for postgraduates and advanced doctors both at home and abroad.Orthodontics is a professional,practical and systematic discipline,therefore,the conventional education model is hard to get a good result.In this study,a new idea of four-component instructional design model(4C/ID)guided by "integration" was explored in the education of orthodontics,combined with the author's study experience in the University of Pennsylvania.The 4C/ID mainly included four elements: learning tasks,supportive information,procedural information and part-task practice,which emphasized in providing learners a set of real,specific and work-oriented complete learning tasks,so as to replace "partial task learning" to "overall task learning".This study explored the 4C/ID and its application on clinical teaching in orthodontics.
ABSTRACT
As an important sub-discipline of dentistry, orthodontics is regarded as the post-graduate education for postgraduates and advanced doctors both at home and abroad. Orthodontics is a professional, practical and systematic discipline, therefore, the conventional education model is hard to get a good result. In this study, a new idea of four-component instructional design model (4C/ID) guided by "integration" was explored in the education of orthodontics, combined with the author's study experience in the University of Pennsylvania. The 4C/ID mainly included four elements: learning tasks, supportive information, procedural information and part-task practice, which emphasized in providing learners a set of real, specific and work-oriented complete learning tasks, so as to replace "partial task learning" to "overall task learning". This study explored the 4C/ID and its application on clinical teaching in orthodontics.
ABSTRACT
Objective To evaluate the root canal deviations in vitro teeth curved root with TF and Protaper instru-ments by cone beam computer tomography( CBCT) . Methods 40 teeth in vitro in the standard collection were ran-domly assigned to two groups, prepared with the crown-down method, the TF group ready to 0. 06/#25; the Pro-taper group ready to F2 . CBCT scans were taken to measure the mesial and distal thicknesses of the tube wall in vitro teeth before and after preparation. The root canal deviation and the rate of shaft center were measured with ref-erence to the formula proposed by Gambill. Results The TF group need less time in preparation and has more effi-ciency(P<0. 05) than the Protaper group; both TF and Protaper devices appeared deformation after 5 root canal preparations in average, no instruments broken. Comparing the offset of the internal and external wall of root canal in 3, 5, 7 mm from the apex, the root canal deviation prepared by the TF group was less than the Protaper group, and its rate of axis center was greater than the Protaper group, closer to 1. Conclusion TF can maintain original root canal morphology in preparing curved root canal, also has higher efficiency;under the noninvasive condition, the root canal forming ability of preparation instruments can be evaluated by CBCT.
ABSTRACT
Aim To study the effects of a novel psychoactive drug,modafinil,on the GABAA receptor-induced current in rat hippocampus pyramidal neurons.Methods Whole-cell patch-clamp recordings were applied in cultured hippocampus pyramidal neurons.Results The GABA-activated currents were blocked by bicuculline,a competitive antagonist of GABAA receptor.Modafinil could partly inhibit IGABA.Pre-treating hippocampus neurons with glibenclamide for 30 min,modafinil-induced inhibition on IGABA was removed.Conclusion Modafinil is different from other psychostimulants.The protection of modafinil may be via modulating ATP sensitive potassium channel activation.