Bone Replacement Grafts in Periodontal Regeneration: Biologically Active Materials or Space-Maintaining Scaffolds? A Critical Narrative Review

Bone replacement grafts are widely used in periodontal regenerative surgery, yet their specific contribution to periodontal tissue regeneration remains uncertain. This critical narrative review examines evidence published through September 2026 on autogenous bone, allografts, xenografts, and alloplasts for periodontal intrabony defects, prioritizing randomized controlled trials, and human histological studies. The synthesis considers comparative efficacy, defect morphology, combination therapies, and discrepancies between clinical, radiographic, and histological outcomes. Regenerative approaches generally improve clinical attachment outcomes compared with open flap debridement; however, evidence does not establish the consistent superiority of any graft category. Defect depth, angle, and residual-wall configuration are associated with treatment response. Clinical attachment gain and radiographic defect fill do not necessarily demonstrate regeneration of the complete periodontal attachment apparatus. Autogenous bone may supply osteogenic cells, whereas selected demineralized allografts have preparation-dependent osteoinductive potential. Xenografts and most alloplasts appear to contribute predominantly through osteoconduction, clot stabilization, and space maintenance. Additional benefits from biologics or barrier membranes vary with defect characteristics and surgical context. Thus, many substitutes may act principally as permissive scaffolds supporting host-mediated regeneration. Graft selection should reflect defect-specific biological and mechanical requirements rather than presumed intrinsic regenerative potency.