The common problem that may encounter surgeons were the change of the volume of iliac bone grafts which used in atrophic region in the alveolar bone because of the resorption of this grafts during healing period. This study aimed to compare between block graft which taken by surgical bur (trephine)and grafts which collected by bone scraper ,in this way the bone graft look like small chips .This study included 10 patients who presented the oral and maxillofacial department in dentistry faculty in Damascus university between 2010-2012 A.D. the patients suffered from sever atrophy in upper and lower alveolar bone for different underlying causes and needed to compromise these atrophy to create a suitable area for dental implantation .The iliac bone grafts were turned into a real bone in the grafted area but the block grafts were saving their volumes more than the grafts collected by bone scraper. We used Mann-Whitney U and SPSS to evaluate the data that collected during the research and the results revealed that the block iliac bone graft which used to compromise the atrophic region would resorb less than the grafts which collected by bone scraper . But these grafts showed that it would be more exposed after surgery than the bone scraper grafts .