Failure of bone regeneration after demineralized bone matrix allograft in human maxillary sinus floor elevation

Background and aims: There are a number of different commercially available demineralized bone matrix (DBM) products with significant differences between products with regard to the osteoinductive effect in bone defects. We aimed to evaluate the cellular response for the osteoinductive effect of the DBM graft materials by immunohistochemistry. Methods: Among five cases of sinus mucosa biopsy from the implant placement into the sinus floor elevation using DBM allograft, one case showed an intact sinus mucosa containing DBM inserted 4 months ago, while the others were severely infected and unable to be compared with each other for the osteoinductive effect of DBM. Immunohistochemistry investigations were undertaken. Results: The multinucleated giant cells were strongly positive for RANKL, cathepsin K, and HSP-90, and consistently positive for lysozyme, TNF-α, CD31, CD68, MMP-2, and MMP-9. The stromal cells were strongly positive for osteonectin and osteocalcin, but weak for BMP-2, BMP-4, RUNX2, TGF-β1, CTGF, and TGase-2. Conclusions: For sinus floor elevation the autogenic bone graft or osteogenic stem cell replacement is necessary, whereas DBM allograft only being insufficient.