الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Vertical ridge augmentation as a critical size defects are usually challenging, several augmentation procedures are used to enable bone regeneration.
The first part of the study focused on clinical use of autogenous bone rings for augmenting localized vertical defects. Autogenous bone rings have the advantageous properties of autogenous bone together with simultaneous implant placement. However, delayed approach offer more secure situation to insert the implant in a fully remodeled bone.
Autogenous bone rings with and without simultaneous implant placement were compared clinically and radiographically using CBCT, radiographic assessment was vertical and horizontal bone gain. Clinical bone width gain was 4.2, 4.6 mm in two stage and one stage approach respectively. Radiographic vertical bone gain was higher in delayed approach 5.2 mm than 3.2mm in the simultaneous approach. It was conducted that autogenous bone rings is a reliable method for vertical bone augmentation especially in two stage approach rather than simultaneous approach.
The second part of the study was in vitro part to 3D scaffolds from a silica containing calciumalkaliorthophosphate (code: GB9S14) utilizing two different fabrication processes, first a replica technique namely the Schwartzwalder Somers method (SSM), and second 3D printing, i.e. Rapid prototyping (RP) and to assess first the mechanical and physical properties of the scaffolds (porosity, compressive strength and solubility), and second their potential to facilitate homogenous colonization with osteogenic cells and extracellular bone matrix formation throughout the porous scaffold architecture. To this end murine osteoblastic cell (ROST-583) were dynamically seeded on both scaffold types under perfusion with seeding concentrations of 3x106 cells. The amount of cells and extracellular matrix as well as osteogenic marker expression was evaluated using hard tissue histology, immunohistochemistry and histomorphometric analysis.
SSM scaffold (SSMS) displayed a significantly greater total porosity (86.9%) than RP scaffolds (RPS) (50%), RPS had significantly more open micropores (38%) than SSMS, this was in addition to exhibiting greater compressive strength and silica release. Regarding the cellular behavior RPS seeded with a 3x106 cell per ml concentration displayed a greater cell and formation Immunoscoring yielded strong osteocalcin expression of cells and matrix in RPS and a moderate expression in SSMS.
The in vivo study of both RP and SSM scaffolds with arteriovenous bundle technique proved by angio CT and immunohistochemical analysis and histomorphometric analysis that AVB is an efficient technique regarding scaffold vascularization in critical size defects after 3 and 6 months of implantation. In addition, RP scaffolds with stem cells and AV bundle had higher percent and mature blood vessels and bone regeneration than the SSM scaffolds. 3D printed CAOP scaffolds are promising material for critical size defects regeneration. The highest total bone area percent was present in the RP scaffolds, cells & AVB group at all time points examined, i.e. 1, 3 and 6 months.
The CAOP scaffolds displayed a high scaffold resorbability with less than 4% residual bone graft in the 4 groups, RP scaffolds exhibited the highest resorbability.
RP, cells & AVB promoted angiogenesis to the highest degree and exhibited a highly proliferative vasculature favoring spreading and branching of the newly formed capillaries resulting in a complex and uniform pattern.
AVB is a predictable method for obtaining intrinsic vascularization in a large segmental discontinuity defect.
RP scaffolds with stem cells and AV bundle facilitated greater bone regeneration and vascularization with more mature blood vessels when compared to the SSM scaffolds.
Combined macro- and microporosity of RP scaffolds appears to be also more beneficial for angiogenesis and bone formation compared to greater overall porosity of SSM scaffolds.