Evaluating Techniques for Vertical Ridge Augmentation via Comparative Study of Clinical Outcomes: A Systematic Review

Background/Objectives: Vertical ridge augmentation (VRA) is often necessary in severe bone atrophy, yet the most predictable approach remains unclear. This systematic review compared Guided Bone Regeneration (GBR) and the Shell Technique (ST) for vertical bone gain (VBG), bone quality, complications, patient-reported outcomes (PROMs), and implant survival. Methods: Following PRISMA 2020 and PROSPERO registration (CRD420251128502), PubMed and Scopus databases were searched. Adults requiring VRA before implants were included. Interventions were GBR using titanium-reinforced dense PTFE (Polytetrafluoroethylene) or collagen membranes and ST using autogenous or allogeneic cortical plates. Results: Both techniques achieved clinically meaningful vertical augmentation. Median VBG was 4.24 mm for GBR (range 2.20-8.78 mm) and 5.16 mm for ST (range 3.10-7.60 mm) at re-entry (typically 4-9 months). Long-term series showed maintained gains for ST up to 10 years and multi-year stability after GBR in selected cohorts. Major early-healing complications were uncommon with both methods. Minor soft-tissue events varied; several GBR cohorts reported more exposures/dehiscence and occasional infections. Implant survival was uniformly high; validated PROMs were seldom reported. Conclusions: GBR and ST both enable vertical reconstruction sufficient for implant placement. ST tended toward higher median VBG but requires greater technical expertise and, when autogenous, adds donor-site morbidity; allogeneic shells reduce harvesting needs. GBR remains a versatile, donor-site-sparing alternative. Standardized outcome (including validated PROMs) reporting and head-to-head randomized trials are needed to refine case selection and confirm comparative effectiveness.