Assisted Wound Healing and Vertical Bone Regeneration with Simultaneous Implant Placement: A Histologic Pilot Study

Purpose: To evaluate the effectiveness of platelet-rich fibrin (PRF) and freeze-dried bone allograft (FDBA) in vertical bone augmentation with immediate implant placement using histologic analysis. Materials and Methods: Six Merino sheep received a total of 36 Brånemark MKIII implants; three implants were placed supracrestally in each tibia with vertical exposure of four threads. Each implant received one of the three grafting options (MinerOss + PRF or MinerOss or PRF). The grafting materials were covered with a resorbable collagen membrane (Mem-Lok 30 × 40 mm, BioHorizons). Animals were sacrificed at 4 and 8 weeks, respectively, and specimens were prepared and collected for histologic analysis. Ground sections and decalcified sections were prepared. Results: The various stages of graft integration into native bone and the implant were observed at different time points, and comparison between the three grafting options was possible. Osteogenic potential with vertical generation of bone was observed in the three groups. At week 4, woven bone formation at the bone graft interface was observed; new bone did not appear to be organized at week 4. At week 8, the graft appeared to be fully replaced by vital mature and wellorganized bone arranged in lamellae with osteocytes encapsulated within the bone. The vertical bone gain at 8 weeks was higher for the PRF + MinerOss group with viable bone extending above the first thread. Both the MinerOss and PRF groups had vertical bone gain extended to the second thread. Conclusion: MinerOss appeared to be effective in vertical bone augmentation with simultaneous implant placement. PRF enhanced vertical bone augmentation when combined with MinerOss. Parole chiave: animal experiments, bone-implant interactions, bone regeneration, bone substitutes, growth factors, guided tissue regeneration