Enamel matrix derivative (EMD) used in periodontal regeneration works principally by which mechanism?

Correct answer: A. Osteopromotion

• A. CORRECT. Enamel matrix derivative (amelogenin-based) acts by OSTEOPROMOTION — it does not itself form bone, contain osteoprogenitor cells, or provide a mineral scaffold. Instead it recreates the biological environment of developing root cementum, stimulating periodontal ligament cells and cementoblasts to proliferate and regenerate a true attachment apparatus of cementum, PDL and bone.
• B. OSTEOINDUCTION is the recruitment and differentiation of mesenchymal stem cells into osteoblasts, mediated by bone morphogenetic proteins — the property of DEMINERALISED FREEZE-DRIED BONE ALLOGRAFT (DFDBA).
• C. OSTEOCONDUCTION is the provision of a passive scaffold along which bone can grow, the property of XENOGRAFTS (bovine bone) and ALLOPLASTS such as hydroxyapatite and beta-tricalcium phosphate.
• D. OSTEOGENESIS is the direct formation of new bone by transplanted living osteoblasts, which only an AUTOGRAFT can provide — the reason autogenous bone remains the gold standard.

Note: Rank the graft materials by biological capability: AUTOGRAFT is the only one that is osteogenic, osteoinductive AND osteoconductive. ALLOGRAFT (DFDBA) is osteoinductive and osteoconductive. XENOGRAFT and ALLOPLAST are osteoconductive only. EMD sits outside this hierarchy as a biological mediator rather than a graft.