Osteoinductive calcium phosphate with submicron topography as bone graft substitute for maxillary sinus floor augmentation: A translational study

Objectives: The aim of this study was the preclinical and clinical evaluation of osteoinductive calcium phosphate with submicron surface topography as a bone graft substitute for maxillary sinus floor augmentation (MSFA). Material and Methods: A preclinical sheep model of MSFA was used to compare a calcium phosphate with submicron needle-shaped topography (BCP_N, MagnetOs Granules, Kuros Biosciences BV) to a calcium phosphate with submicron grain-shaped topography (BCP_G) and autologous bone graft (ABG) as controls. Secondly, a 10-patient, prospective, randomized, controlled trial was performed to compare BCP_N to ABG in MSFA with two-stage implant placement. Results: The pre-clinical study demonstrated that both BCP_N and BCP_G were highly biocompatible, supported bony ingrowth with direct bone apposition against the material, and exhibited bone formation as early as 3 weeks post-implantation. However, BCP_N demonstrated significantly more bone formation than BCP_G at the study endpoint of 12 weeks. Only BCP_N reached an equivalent amount of bone formation in the available space and a greater proportion of calcified material (bone + graft material) in the maxillary sinus compared to the “gold standard” ABG after 12 weeks. These results were validated in a small prospective clinical study, in which BCP_N was found comparable to ABG in implant stability, bone height, new bone formation in trephine core biopsies, and overall clinical outcome. Conclusion: This translational work demonstrates that osteoinductive calcium phosphates are promising bone graft substitutes for MSFA, whereas their bone-forming potential depends on the design of their surface features. Netherlands Trial Register, NL6436.