Extreme maxillary atrophy results from partial or total maxillary bone defect, affecting the alveolar and basal segments. The residual bone is only a few millimeters high and does not allow retention of dental prostheses (complete edentulation), or placing implants. Bone reconstruction with cranial bone grafts usually allows obtaining enough bone volume in a single step to place implants for prosthetic rehabilitation, 3 months later.Reconstruction begins by inserting bone grafts on the sinus floor. The pre-maxilla is then rebuilt with bone grafts placed on the nose floor then on the palate and vestibule. The premolar and molar sectors are rebuilt last with vestibular and palatine bone grafts assembled and stabilized by screws, or steel wire rings, and reinforced on their deep portion with diploe sheets.Extreme maxillary atrophy reconstruction with cranial bone grafts is a reliable technique with reproducible results and few complications (sinusitis, bone sequester). Nevertheless, it requires strong experience to adequately perform harvesting and reconstruction.