The purpose of this study was to investigate the cortical bone thickness of the inter-dental area of both jaws for orthodontic miniscrew placement. The cone-beam computerized tomography images of 32 non-orthodontic ad...The purpose of this study was to investigate the cortical bone thickness of the inter-dental area of both jaws for orthodontic miniscrew placement. The cone-beam computerized tomography images of 32 non-orthodontic adults with normal occlusion were taken to measure the cortical bone thick- ness in both.jaws. One-way analysis of variance （ANOVA） was used to analyze the differences in cortical bone thickness. Buccal cortical bone in the mandible was thicker than that in the maxilla. In the maxilla, cortical bone thickness was thicker in the buccal side than in the palatal side. Buccal cortical bone thickness in the mandible was thickest at the site distal to the first molar, and in the maxilla it was thickest at the site mesial to the first molar, while in the palatal side of maxilla it was thickest at the site mesial to the second premolar. The changing pattern of cortical bone thickness varies at different sites. In the buccal side of maxilla, the thinnest cortical bone thickness was lbund to be at 4 mm level from the alveolar crest, while the thickest was at 10 mm level （except for the site mesial to the first premolar）. The buccal cortical bone thickness at the sites mesial or distal to the first molar in the mandible and palatal cortical bone thickness of maxilla tended to increase with increasing distance from the alveolar bone.展开更多
Despite an increasing number of tissue-engineered scaffolds have been developing for bone regeneration,simple and universal fabrication of biomimetic bone microstructure to repair full-thickness bone defects remains a...Despite an increasing number of tissue-engineered scaffolds have been developing for bone regeneration,simple and universal fabrication of biomimetic bone microstructure to repair full-thickness bone defects remains a challenge and an acute clinical demand due to the negligence of microstructural differences within the cortex of cancellous bone.In this work,a biomimetic sandwich-layered PACG-CS@Mn(Ⅲ)hydrogel(SL hydrogel)was facilely fabricated in an end-tail soaking strategy by simply post-crosslinking of poly(acryloyl 2-glycine)-chitosan(PACG-CS)composite hydrogel using trivalent manganese solutions.Taking the merits of in-situ formation and flexible adjustment of chain entanglements,hydrogen bonds and metal chelate interactions,SL hydrogel with sandwich-like three-layered structures and anisotropic mechanical performance was easily customized through control of the manganese concentration and soaking time in fore-and-aft sides,simulating the structurally and mechanically biomimetic characteristics of cortical and cancellous bone.Furthermore,the produced SL hydrogel also demonstrated favorable biocompatibility and enhanced MnSOD activity via a peroxidase-like reaction,which enabled the excellent radical scavenging efficiency and anti-inflammatory regulation for facilitating the activity,proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells(BMSCs).In vivo studies further revealed that these SL hydrogels achieved restrictive pro-vascular regeneration through their stratified structure,thereby promoting the differentiation of osteoblasts.Simultaneously,the mechanical cues of stratified structure could mediate macrophage phenotype transitions in accordance with stem cell-osteoblast differentiation process via the PI3K-AKT pathway,resulting in robust osteogenesis and high-quality bone reconstruction.This facile yet efficient strategy of turning anisotropic hydrogel offers a promising alternative for full-thickness repair of bone defects,which is also significantly imperative to achieve high-performance scaffolds with specific usage requirements and expand their clinic applicability in more complex anisotropic tissues.展开更多
文摘The purpose of this study was to investigate the cortical bone thickness of the inter-dental area of both jaws for orthodontic miniscrew placement. The cone-beam computerized tomography images of 32 non-orthodontic adults with normal occlusion were taken to measure the cortical bone thick- ness in both.jaws. One-way analysis of variance （ANOVA） was used to analyze the differences in cortical bone thickness. Buccal cortical bone in the mandible was thicker than that in the maxilla. In the maxilla, cortical bone thickness was thicker in the buccal side than in the palatal side. Buccal cortical bone thickness in the mandible was thickest at the site distal to the first molar, and in the maxilla it was thickest at the site mesial to the first molar, while in the palatal side of maxilla it was thickest at the site mesial to the second premolar. The changing pattern of cortical bone thickness varies at different sites. In the buccal side of maxilla, the thinnest cortical bone thickness was lbund to be at 4 mm level from the alveolar crest, while the thickest was at 10 mm level （except for the site mesial to the first premolar）. The buccal cortical bone thickness at the sites mesial or distal to the first molar in the mandible and palatal cortical bone thickness of maxilla tended to increase with increasing distance from the alveolar bone.
基金supported by the National Natural Science Foundation of China(52373162,82002291 and 51973226)Beijing Natural Science Foundation(L244037)+1 种基金National Key R&D program of China(2020YFC2004906)Key Program of National Natural Science Foundation of China(81930069).
文摘Despite an increasing number of tissue-engineered scaffolds have been developing for bone regeneration,simple and universal fabrication of biomimetic bone microstructure to repair full-thickness bone defects remains a challenge and an acute clinical demand due to the negligence of microstructural differences within the cortex of cancellous bone.In this work,a biomimetic sandwich-layered PACG-CS@Mn(Ⅲ)hydrogel(SL hydrogel)was facilely fabricated in an end-tail soaking strategy by simply post-crosslinking of poly(acryloyl 2-glycine)-chitosan(PACG-CS)composite hydrogel using trivalent manganese solutions.Taking the merits of in-situ formation and flexible adjustment of chain entanglements,hydrogen bonds and metal chelate interactions,SL hydrogel with sandwich-like three-layered structures and anisotropic mechanical performance was easily customized through control of the manganese concentration and soaking time in fore-and-aft sides,simulating the structurally and mechanically biomimetic characteristics of cortical and cancellous bone.Furthermore,the produced SL hydrogel also demonstrated favorable biocompatibility and enhanced MnSOD activity via a peroxidase-like reaction,which enabled the excellent radical scavenging efficiency and anti-inflammatory regulation for facilitating the activity,proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells(BMSCs).In vivo studies further revealed that these SL hydrogels achieved restrictive pro-vascular regeneration through their stratified structure,thereby promoting the differentiation of osteoblasts.Simultaneously,the mechanical cues of stratified structure could mediate macrophage phenotype transitions in accordance with stem cell-osteoblast differentiation process via the PI3K-AKT pathway,resulting in robust osteogenesis and high-quality bone reconstruction.This facile yet efficient strategy of turning anisotropic hydrogel offers a promising alternative for full-thickness repair of bone defects,which is also significantly imperative to achieve high-performance scaffolds with specific usage requirements and expand their clinic applicability in more complex anisotropic tissues.
