13 patients will be included in this study with a badly destructed upper molar indicated for extraction. Cone beam computerized tomography images revealed the presence of a large bone defect associated with oro-antral communication with the maxillary sinus. after extraction, The prefabricated allogenic scaffold will be seated. then 6 months later, implant will be inserted.

13 patients will be included in this study with a badly destructed upper molar indicated for extraction. Cone beam computerized tomography images revealed the presence of a large bone defect associated with oro-antral communication with the maxillary sinus. : Extraction will be performed atraumatically using a piezotome surgical motor with an extraction kit. After removal of tooth, oro-antral communication will be verified .The prefabricated CAD-CAM allogenic bone will be seated and covered with nonporous d-PTFE membrane which was secured with simple interrupted sutures. After 6 months, a new CBCT scan will be performed. A mucoperiosteal flap will be reflected ,and a bone biopsy will be taken using a trephine bur. Under strictly aseptic circumstances, the selected implant will be inserted

Inclusion Criteria:

• ≥ 20 badly destructed upper molar indicated for extraction CBCT revealed the presence of a large bone defect associated with oro-antral communication with the maxillary sinus

Exclusion Criteria:

• any systemic disesse affect healing heavy smoker sinus disease