Does the use of intermediate abutments impact screw-retained implant-supported fixed partial prostheses outcomes? A systematic review and meta-analysis of randomized controlled trials.

Objectives To evaluate the impact of intermediate abutments on screw-retained implant-supported fixed dental prostheses (FDPs), primarily assessing marginal bone loss (MBL) and secondarily probing depth (PD), bleeding on probing (BoP), implant survival, mechanical complications, and patient satisfaction.Data Random-effects meta-analyses were conducted using weighted mean differences (WMD) for continuous outcomes and risk differences for dichotomous outcomes. Risk of bias was assessed using the Cochrane RoB 2 tool, and the certainty of evidence (CoE) using the GRADE approach.Sources A systematic search was conducted up to May 2025 across MEDLINE (PubMed), Scopus, Web of Science, Cochrane Library, Embase, and Google Scholar.Study Selection Randomized controlled trials (RCTs) with ≥6 months of follow-up comparing abutment-level (AL) versus implant-level (IL) connections in partially edentulous patients rehabilitated with screw-retained FDPs.Results Three RCTs (8 publications) with different follow-up periods, involving a total of 126 patients and 341 implants, were included. A statistically significant reduction in MBL was observed at 36 months at implant level (MD:-0.13 mm; 95% CI: -0.23 to -0.03; p=0.01; 2 RCTs; 162 implants; moderate CoE). No significant differences in MBL were observed at 12 or 60 months. PD was significantly reduced in the AL group at 36 months (MD:-0.66 mm; 95% CI: -1.13 to -0.19; p=0.01; 2 RCTs; 187 implants; low CoE) and at 60 months (MD:-0.60 mm; 95% CI: -0.91 to -0.29; p<0.001; 1 RCT; 115 implants; low CoE). No significant differences were found in BoP, implant survival, mechanical complications, or patient satisfaction at any follow-up time point.Conclusions Intermediate abutments may improve soft-tissue health by reducing PD without increasing complications or implant failure. Despite a minor, non-clinically relevant reduction in MBL, they remain a viable option for screw-retained FDPs.Clinical Relevance Intermediate abutments slightly reduce probing depth and marginal bone loss in multi-unit implant prostheses, but the clinical impact is minimal, with no effect on implant survival or mechanical complications.Prospero Registration CRD42023475778.