Effects of Maxillary Sinus Augmentation on Endosseous Dental Implant Survival: A Systematic Review and Meta-Analysis

Maxillary sinus floor augmentation (MSFA) is a procedure for rehabilitating the atrophic posterior maxilla, but the optimal surgical technique and its long-term impact on implant survival remain debated. This systematic review and meta-analysis were conducted to synthesize the available evidence on the long-term survival of endosseous dental implants placed in augmented maxillary sinuses. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a search of major electronic databases was performed to identify randomized controlled trials (RCTs) and cohort studies reporting implant survival rates after MSFA with at least one year of follow-up. The primary outcome was implant failure rate. The secondary outcome was marginal bone loss (MBL). Two reviewers independently performed study selection, data extraction, and risk of bias assessment using the Cochrane Risk of Bias 2 (RoB 2) and Risk Of Bias In Non-randomized Studies of Interventions (ROBINS-I) tools. A random-effects model with Hartung-Knapp adjustment was used for meta-analysis, employing the Freeman-Tukey double arcsine transformation for proportions. Subgroup analysis and meta-regression were performed to explore heterogeneity. The certainty of the evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) approach. Twenty-two studies, comprising 6,860 implants, were included. The pooled implant failure rate was 3% (95% confidence interval {CI}: 2-5%), corresponding to a cumulative survival rate of 97%. Significant heterogeneity was observed (I²=86.3%). Subgroup analysis revealed a significantly lower failure rate for implants placed via a crestal approach compared to a lateral window approach (p<0.001). The pooled mean MBL was 1.17 mm (95% CI: 0.59-1.75 mm), with very high heterogeneity (I²=99.6%). Formal tests did not indicate significant publication bias. The certainty of the evidence for both implant failure and MBL was graded as low. Endosseous dental implants placed in augmented maxillary sinuses demonstrate a high long-term survival rate, confirming the predictability of MSFA. The crestal approach is associated with fewer implant failures, although this association may be influenced by case selection bias. The overall low certainty of the evidence, driven by methodological heterogeneity and the predominance of observational studies, highlights the need for standardized, long-term RCTs to refine clinical protocols and strengthen treatment guidelines.