In this study the buccal fat pad derived stem cells (BFPSCs) is harvested from buccal fat pad tissue of the patients receiving posterior mandible augmentation. In the test group the patients receive a combination of platelet rich fibrin (PRF) and freeze dried bone allograft (FDBA) (SureOss, Hansbiomed, Korea) loaded with BFPSCs. The control group receivesFDBA (without any cells)+PRF. In all the groups the combination are placed between the recipient site and the block graft obtained from lateral ramus. The results will be evaluated by cone beam computed tomography (CBCT)and hematoxylin and eosin staining in 6 months.