Thirteen patients were treated for elevation of the maxillary sinus floor with autogenous or composite (autogenous bone + hydroxyapatite granules) bone grafts and endosseous implants. Bone biopsies were taken both at graft positioning and at implant placement. Histologic and histomorphometric results suggest that graft architecture, conformation, and composition may influence the mean bone content at the end of the healing. Iliac bone grafts contained 53% bone, while chin bone grafts contained 66% bone. Composite bone grafts had the smallest percentage of bone: 44.3%. Chin block bone grafts had the largest percentage of bone content (69.3%), while chin particulate bone graft conformation had 62.6%. Although particulate grafts healed in only 4 months, bone quality and quantity allowed earlier implant placement. Schlagwörter: atrophic maxillae, autogenous bone graft, bone graft, composite graft, sinus lift