الفهرس 
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Abstract
Efficacy of Vented Bone Block Fixed with Laser Sintered Implants Restoring Defects In posterior mandibular zone Dissertation abstract Problem statement Onlay grafting has been used successfully in the correction of vertically deficient edentulous ridges, although the reported two-stage approach results in considerable resorption of the bone graft before implant insertion. Xenogenic bone grafting overcomes the obstacles of autogenic grafting such as amount needed and the second surgery site and have been manufactured by the tutoplast technology. Direct laser metal sintering technology applied in implant production to improve implant success rate in such difficult bone condition. So, this study was directed to evaluate efficacy of using a vented xenogenic bone block fixed directly with DLMS implants in posterior maxilla. Patients and Methods Forteen patients were selected which are free from any systemic disease, aged from 18-50 years old and have a vertical and horizontal bone defect in the posterior mandibular region ranged from 3 to 5 mm 3 dimensionally. All patients within this study received DLMS dental implant installed in the posterior mandibular region as a fixative screw for the xenogenic block graft and were subjected to delayed loading after 6 month. All patients were evaluated clinically at regular time intervals at 6 ,9 and 12 months postoperatively regarding to implant stability, periodontal probing depth, Modified sulcus bleeding Index (mSBI) and marginal bone loss (MBL). Results Evaluating this technique in restoring a vertical and horizontal mandibular defect we found that, a statistical significant difference was recorded immediately comparing all the time intervals, at the placement of final crown, 9 and 12 month with (P<0.001) regarding to implant stability. Also, a statistical significant difference was recorded comparing all the time intervals with (P< 0.001) except comparing (T2-T3) there was no statistical deference with (P=0.06) regarding the marginal bone loss. Regarding the (MSBI) and the pocket depth a statistical significant differences were recorded between (T1-T2) (T1-T3) with a (P1=0.027 P2=0.002 \ P1=0.001 P2=0.001) respectively and no statistical difference between (T2-T3) with (P3=0.08\ P3=0.09) respectively. Conclusion We concluded that using the xenogenic bone block fixed with DLMS implants in restoring posterior mandibular vertical and horizontal defects have shown a marked graft resorption and graft dehiscence. On the other hand, the DLMS implants has shown a marked increase in stability over time and fast natural bone formation but failed to ossteointegrate with the xenogenic block when used at the same time as a fixative screw for the block.