Comparison of Allogeneic Bone Plate and Guided Bone Regeneration Efficiency in Horizontally Deficient Maximly Alveolar Ridges  
[PERSON]  
1 Department of Oral Implantology, Faculty of Dentistry, Istanbul University, Fatih, Istanbul 34093, Turkey 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31  
A variety of surgical techniques may be performed to provide more bone volume to the horizontally deficient alveolar ridges and consequently allow for implant placement coordinated with a prosthodonic treatment plan. Alveolar bone loss can be reconstructed using different strategies, such as GBR, inlay and onlay grafting, free vascularized autografts, distraction osteogenesis, and ridge splitting. The amount and configuration of osseous defects determine the type, magnitude, and prognosis of the bone-augmentation modality [4].  
GBR is a reliable technique for hard tissue augmentation. It allows for reconstruction of horizontal and vertical defects, providing sufficient bone volume for osseointegrated dental implants to occur. Horizontal ridge augmentation via GBR with the combination of particulate bone graft materials and resorbable collagen membrane is a frequently re-ported surgery in the literature [5]. Autogenous bone graft is considered the gold standard for use in hard tissue augmentation procedures, providing critical minerals, proteins, and vital bone-related cells to the recipient site for bone healing, resulting in the improved success of bone augmentation. By contrast, the use of autogenous bone might induce critical morbidity at the donor site, such as postsurgical pain, increased time/costs, and unpredictable resorption rate [6]. ABB is an osteoconductive bone graft material that can provide a sufficient scaffold for new bone growth; moreover, the use of 50% ABB minimizes the need for a large quantity of harvested host bone. The combination of ABB and autogenous bone graft alters the resorption rate of the autogenous bone during the healing process, whereas particulate autogenous bone enhances osteogenic factors [7].  
One of the most important steps in a successful hard tissue augmentation is the preclusion of bone graft movement. Sufficient stability and minimal stress exposure are necessary to allow for new bone formation since a new vascular network is prone to deterioration caused by mechanical conditions [8]. CS is a human-derived allogeneic cancellous block that is produced of osseous structure of femoral heads. CS is a stable and rigid plate which plays a critical role in the \"shell technique\" for hard tissue augmentation. The shell technique creates space between the host bone and the cortical plate and can thus be filled with a variety of different particulate bone grafting materials. Two screws are recommended to fix CS to the residual bone to prevent rotation [9].  
Cone-beam computed tomography (CBCT) images are approved for their capability to assess hard tissue augmented sites and their contours. While CBCT scans allow for nearly the same exact measurement of alveolar bone volume as CT and micro-CT scans, CBCT also offers some advantages, such as reduced radiation dose, lower cost, smaller device size, and high resolution [10].  
The principal objective of this retrospective study was to evaluate volumetric changes by means of CBCT following horizontal alveolar ridge augmentation, either by using CS with a combination of particulate autogenous bone and bovine bone minerals covered by a resorbable collagen membrane (test group), or by using a mixture of an inorganic bovine bone substitute and particulate autogenous bone with resorbable collagen membrane as GBR (control group). Additionally, complications and insertion torques between groups were recorded. The null hypothesis was that there would be a difference between the two groups.