الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
The missing of teeth in the alveolar bone stimulate different biological actions that form anatomical changes. The process of healing of the socket is divided to three phases: inflammatory, proliferative, and modeling/remodeling, where overlapping is usually done. Bone modelling is the process of bone resorption on the socket walls that leads to a dimensional change in the alveolar ridge, while the Bone remodelling is the process of replacing woven bone with lamellar bone.
simple tooth extraction is the most dental procedure done by the dentists regularly (Garibaldi, 1998). The most common complications are severe pain, edema, prolonged bleeding, infection, trismus and dry socket.
Different ways have been achieved to keep the architecture of residual alveolar ridge by using of bone substitutes,collagen plug and bone packed into the extraction sockets. Autologous fibrin is considered the best way to avoid cross infection, so bone regeneration and wound healing in extraction sockets are activated by with PRF.
bone block is used in Horizontal bone augmentation which is added to the defected area to have a successful outcome the most important part is the stabilization and intimate contact of bone block grafts to the recipient bone bed, it can be done by using bone fixation screws. The success of FDBA and DFDBA block graft material application in horizontal ridge augmentation have been noticed and lowering the donor site morbidity risk associated with autogenous block graft, although another comparative studies ensure the histological healing evaluation of the allogenic blocks.
Two of important techniques used in horizontal ridge augmentation are Khoury and sausage techniques, from Khoury technique point of view regarding bone regeneration it utilizes autogenous divided bone blocks harvested from the patient and the Urban technique enclose the biomaterials by membranes.
According to Khoury technique, the first layer, which is formed of the thin cortical plate, gives the alveolar crest form and shape. It is screwed at a distance far away from the native bone, instead of the intimate contact, so it leaves a gap between the atrophic alveolar ridge and the plate. Thus, the final thickness and shape of the new alveolar bone crest is fixed.
The second layer is consisted of the cancellous and the cortical bone particles, So Filling the space between the alveolar crest and the plate (Khoury and Khoury, 2007). Which have a better potential for the revascularization and the regeneration (Khoury and Hanser, 2019). They are packed properly to prevent the invasion of fibroblast. The final shape of the grafted ridge is resembling to an iliac graft, with thin external cortical layer and thick internal cancellous bone.
The aim of the present study was to evaluate the efficacy of umbrella technique combined with sticky bone in horizontal ridge augmentation using:
A. Buccolingual width changes measured in CBCT and patient satisfaction as primary outcome.
B. Bone quality using histomorphometric analysis as secondary outcome.
In our current study we used the umbrella technique in the lower posterior area for the horizontal ridge augmentation.
In the current study we use the tenting screw pole technique, which is one of the methods utilized by oral surgeons in horizontal ridge augmentation for the ability of placement of dental implant. The target of this study was to evaluate the efficacy of the umbrella technique for the horizontal ridge augmentation.
By using tenting screws as a space maintenance tool to maintain soft tissue away from the grafted material, the screw tent-pole approach lowers graft mobility and lessens external strain on the woven bone region. The first time screws were used to retain gaps.
The tenting or umbrella technique is used to augment the horizontal bone prior to implant insertion in severe atrophic alveolar ridge defects using xenograft alone with or without I PRF or in combination with autogenous graft from an external donor site such as the iliac crest.
The umbrella technique has excellent aesthetic and functional results when large vertical defects are repaired without the use of autogenous bone, and it also exhibits better osseointegration results without the use of autogenous graft. However, vertical bone grafts still need to be evaluated for long-term implant loading.
At baseline, the mean radiographic bone width value showed increase after 6 months by using CBCT preoperative and postoperative superimposition technique, also the core biopsy technique done for histological analysis showed post operatively showing the increase in the percentage of area fraction and osteocytes of new bone.