Autologous Bone Versus Xenograft and Their Combination in Vertical Ridge Augmentation: An Analysis of Graft Resorption and Implant Survival—A Systematic Review

Background: The integrity of the alveolar ridge is compromised by tooth loss or trauma, initiating chronic resorption that alters bone morphology. Vertical bone augmentation (VBA) is a complex procedure required to rehabilitate severe atrophy. Currently, there is debate regarding the effectiveness of autologous bone versus xenografts and their combination to optimize bone regeneration and ensure dimensional stability. Objectives: To synthesize evidence on the efficacy of VBA by comparing autologous bone, xenografts, and their combination. Specifically, to evaluate vertical bone gain, volumetric stability and resorption, implant survival, complications, and whether combined grafts offer clinical advantages. Methods: A systematic review was conducted following PRISMA 2020 guidelines. MEDLINE, Scopus, SciELO, and Web of Science were searched up to January 2026. Risk of bias was assessed, using RoB 2 for randomized studies and ROBINS-I for non-randomized studies. Results: From 1517 initial records, 9 studies were included and 3 showed high risk of bias. Iliac crest grafts achieved the greatest vertical bone gain but also exhibited higher resorption compared to calvarial grafts. Xenografts (Bio-Oss) demonstrated superior volumetric stability, maintaining 10–13% more residual volume than autologous blocks. The most frequent complication was soft tissue dehiscence. Conclusions: VBA is an effective procedure. The combination of autologous bone and xenograft may represent a balanced approach, providing both biological potential and volumetric stability. Graft origin significantly influences outcomes and morbidity. However, current evidence is limited by methodological heterogeneity and small sample sizes, highlighting the need for well-designed clinical trials with standardized protocols and long-term follow-up.