The outcomes of ridge augmentation via tunneling technique: a meta-analysis and systematic review

Background This review aims to evaluate dimensional changes in the alveolar ridge and complications following ridge augmentation using tunnelling techniques. Methods An electronic search was conducted in PubMed , Embase , and Web of Science to identify randomized and non-randomized prospective studies and retrospective human case-control or cohort studies comparing the efficacy of ridge augmentation using tunneling techniques during 1st January 1980 to 31st December, 2025. Two calibrated independent reviewers assessed the selected studies. The main outcome measured was the horizontal bone gain (HBG) and vertical bone gain (VBG) evaluated from the initial baseline visit to the final follow-up. Meta-analysis was performed to analyze HBG and VBG and their differences between the test group (undergoing tunneling ridge augmentation) and controls (ridge augmentation via flapped approaches). Meta-regression was performed to investigate the contributing factors of these outcomes. Results Eleven studies enrolling 491 patients were selected in this review. The pooled HBG and VBG were 4.58 mm (95% Confidence Interval (CI) [2.61,6.54], p < 0.01) and 4.86 mm (CI [3.53,6.20], p < 0.01), respectively. Compared to the control group, the HBG was not significantly different between the two groups (0.65 mm, CI [-0.01,1.31], p = 0.05). In contrast, the test group had significantly greater VBG than the control group (0.70 mm, CI [0.26,1.14], p < 0.01). Most of the reported complications were temporary and mild. However, a few cases involved serious complications, such as nerve injury and graft failure. Conclusion Tunneling techniques appear to be a feasible approach for horizontal and vertical ridge augmentation. Evidence remains insufficient to determine whether tunneling techniques increase bone gain or reduce complications compared with conventional flapped approaches.