Clinical evaluation of maxillary sinus floor elevation with or without bone grafts: a systematic review and meta-analysis of randomised controlled trials with trial sequential analysis

Introduction Our goal was to systematically review the current evidence comparing the relative effectiveness of two maxillary sinus floor elevation (MSFE) approaches (internal and external) without bone grafts with that of conventional/grafted MSFE in patients undergoing implantation in the posterior maxilla. Material and Methods Medical databases (PubMed/Medline, Embase, Web of Science, and Cochrane Library) were searched for randomised controlled trials published between January 1980 and May 2023. A manual search of implant-related journals was also performed. Studies published in English that reported the clinical outcomes of MSFE with or without bone material were included. The risk of bias was assessed using the Cochrane Handbook Risk Assessment Tool. Meta-analyses and trial sequence analyses were performed on the included trials. Meta-regression analysis was performed using pre-selected covariates to account for substantial heterogeneity. The certainty of evidence for clinical outcomes was assessed using GRADEpro GDT online (Guideline Development Tool). Results Seventeen studies, including 547 sinuses and 696 implants, were pooled for the meta-analysis. The meta-analysis showed no statistically significant difference between MSFE without bone grafts and conventional MSFE in terms of the implant survival rate in the short term (n = 11, I2 = 0%, risk difference (RD): 0.03, 95% confidence intervals (CI): –0.01–0.07, p = 0.17, required information size (RIS) = 307). Although conventional MSFE had a higher endo-sinus bone gain (n = 13, I2 = 89%, weighted mean difference (WMD): –1.24, 95% CI: –1.91– –0.57, p = 0.0003, RIS = 461), this was not a determining factor in implant survival. No difference in perforation (n = 13, I2 = 0%, RD = 0.03, 95% CI: –0.02–0.09, p = 0.99, RIS = 223) and marginal bone loss (n = 4, I2 = 0%, WMD = 0.05, 95% CI: –0.14–0.23, p = 0.62, no RIS) was detected between the two groups using meta-analysis. The pooled results of the implant stability quotient between the two groups were not robust on sensitivity analysis. Because of the limited studies reporting on the visual analogue scale, surgical time, treatment costs, and bone density, qualitative analysis was conducted for these outcomes. Conclusions This systematic review revealed that both non-graft and grafted MSFE had high implant survival rates. Owing to the moderate strength of the evidence and short-term follow-up, the results should be interpreted with caution.