Purpose: The purpose of this study was to analyze healthy bone formation by means of histology and immunohistochemistry after grafting with a mixture of autologous ground calvarial bone, inorganic xenograft, platelet-rich plasma (PRP), and recombinant human tissue factor (rhTF). Materials and Methods: Maxillary sinus floor augmentation was performed on 3 patients by grafting with 5 to 10 mL of a paste consisting of autologous powder from calvarial bone (diameter 1 mm), 50% v/v anorganic bovine bone mineral xenograft (PepGen P-15, a new tissue-engineered bone replacement graft material), PRP (1.8 × 10⁶ platelets/mm³ plasma), and about 1 µg rhTF. Six and 10 months after grafting, bone cores were extracted for implant fixation and analyzed. Results: Histology demonstrated a high degree of inorganic xenograft integration and natural bone regeneration. Both the xenograft and newly synthesized bone were colonized with osteocytes and surrounded by osteoblasts. Six-month-old bone cores demonstrated a ratio of synthesized bone to xenograft particles ratio of 0.5, whereas 10-month-old cores demonstrated a ratio of 2. A low degree of inflammation could also be observed using S100A8 immunohistochemistry. Discussion: Autologous grafting in edentulous patients is a complex procedure; the successful substitution of synthetic analogs for ground bone is a major challenge. Conclusion: In this investigation, it was shown that inorganic xenograft in the harvested bone paste could be safe for patients and had high bone regeneration capacity over time. The sinus graft showed intense bone formation 6 months after grafting and a further increase in bone growth 10 months after grafting.