Comparative effectiveness of alloplastic and biologic grafts in maxillary sinus augmentation: a systematic review

BACKGROUND: Maxillary sinus augmentation is a well-established procedure to increase posterior maxillary bone volume for implant placement. Various graft materials are used, including autografts, allografts, xenografts, and alloplasts, but the clinical performance of alloplasts remains debated. METHODOLOGY: A systematic review was performed following PRISMA guidelines to compare histological, histomorphometric, radiographic, and clinical outcomes of sinus lift procedures using different grafts. Electronic searches were conducted in eight databases. Eligible studies were human clinical trials (RCTs, cohorts) comparing at least two graft materials and reporting new bone formation, graft resorption, implant survival, or complications. Eighteen studies met the inclusion criteria. Risk of bias was assessed using Cochrane RoB 2.0 and ROBINS I V2 tool. RESULTS: Alloplastic grafts demonstrated comparatively lower new bone formation than autogenous and allogeneic grafts, and were generally inferior to xenografts in terms of regenerative potential. They exhibited higher residual graft content, suggesting slower resorption when compared with biologic grafts. In contrast, xenografts and allografts showed more favorable integration. Volumetric outcomes indicated that alloplastic grafts provided better dimensional stability than autografts but were less effective than xenografts in maintaining graft volume and space. Radiographic findings further supported superior space maintenance with xenografts compared to alloplastic grafts. Implant survival rates were high across all graft types; however, biologic grafts demonstrated relatively improved success and lower marginal bone loss compared with alloplastic grafts. CONCLUSION: Autografts demonstrated the highest effectiveness in maxillary sinus augmentation, followed by xenografts and alloplastic grafts, indicating a comparatively lower regenerative potential of alloplastic materials. Nevertheless, alloplastic grafts may still be considered a viable alternative in selected clinical scenarios, particularly where minimizing donor-site morbidity or reducing immunological and infection-related risks is a priority. High-quality, long-term randomized trials are needed to confirm these findings and optimize graft selection.