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).
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 < 0.0001). Bone-to-implant contact was not significantly influenced by the ratio of Bio-Oss and autogenous bone (P = 0.19) or the origin of the autogenous bone (P = 0.72). Fluorochrome labelling revealed extensive variation in bone-to-implant contact formation over time. The labelling at weeks 2–3 was significantly increased with A compared to E (OR = 8.1 CI: 5.0–13.1, P < 0.0001), whereas E showed a significantly increased labelling at weeks 8–9 compared to A (OR = 0.5 CI: 0.3–0.7, P = 0.0028).
The hypothesis of no differences in bone-to-implant contact between the various treatment modalities was rejected since the bone-to-implant contact was significantly increased with autogenous bone or Bio-Oss mixed with autogenous bone as compared to Bio-Oss. Early bone-to-implant contact formation was more advanced with autogenous bone. No differences between the use of mandibular or iliac bone grafts were observed since the bone-to-implant contact was not significantly influenced by the origin of the bone graft.