Long-Term Outcomes of Short versus Long Dental Implants with Sinus Lift in Atrophied Posterior Maxillae: A Systematic Review and Meta-Analysis

This study aimed to evaluate implant outcomes, including success or survival, complications, and marginal bone loss (MBL), in randomized controlled trials (RCTs), comparing short versus long implants with sinus augmentation (SA) after 5 or more years of loading. The objective was to update the qualitative and quantitative evidence on this topic and provide a comprehensive analysis of the previously identified implant outcomes. Electronic searches were conducted in 4 scientific databases from 2016 through 2024. Only RCTs with a minimum follow-up period of 5 years were included (7 studies); these were rated using the revised Cochrane risk-of-bias (RoB 2) tool for main outcomes. The overall risk of bias was “High” in 5 studies, whereas 2 studies were rated as “Some concerns.” The risk ratio (RR) and 95% confidence interval (CI) were calculated with Stata software, version 18, for implant success and survival (2.37; 95% CI: 0.83-6.78, P = .11) and for implant complications (0.88; 95% CI: 0.64-1.21, P = .43). The Cohen’s d for MBL was −0.41 mm (95% CI: −0.72 to −0.09, P = .01). There was no statistically significant difference in implant success and survival between short and long implants with SA (P = .60). Due to the overall high risk of bias, no definitive conclusions can be drawn regarding the success or survival of short versus long implants. Further RCTs with clear descriptions of implant outcomes, rigorous standardization and calibration protocols, meticulous sample-size calculation, and extended follow-up periods are needed.