OBJECTIVES: The objective was to test the hypotheses: (i) no differences in bone-to-implant contact formation, and (ii) no differences between the use of autogenous mandibular or iliac bone grafts, when autogenous bone, Bio-Oss mixed with autogenous bone, or Bio-Oss is used as graft for the maxillary sinus floor augmentation. MATERIAL AND METHODS: Bilateral sinus floor augmentation was performed in 40 mini pigs with: (A) 100% autogenous bone, (B) 75% autogenous bone and 25% Bio-Oss, (C) 50% autogenous bone and 50% Bio-Oss, (D) 25% autogenous bone and 75% Bio-Oss, or (E) 100% Bio-Oss. Autogenous bone was harvested from the iliac crest or the mandible and the graft composition was selected at random and placed concomitant with the implant placement. The animals were euthanized 12 weeks after surgery. Bone-to-implant contact was estimated by stereological methods and summarized as median percentage with 95% confidence interval (CI). Bone-to-implant contact formation was evaluated by fluorochrome labelling and assessed by median odds ratios (OR) with 95% (CI). RESULTS: Median bone-to-implant contact was: (A) 42.9% (95% CI: 32.1-54.5%), (B) 37.8% (95% CI: 27.1-49.9%), (C) 43.9% (95% CI: 32.6-55.9%), (D) 30.2% (95% CI: 21.6-40.3%), and (E) 13.9% (95% CI: 11.4-16.9%). Bone-to-implant contact was significantly higher for A, B, C, D as compared to E (P