What is the impact of titanium base versus multi-unit abutments on immediate loading outcomes: a systematic review

PURPOSE: This systematic review, conducted per PRISMA guidance, evaluated clinical outcomes of titanium-base (TiB) versus multi-unit (MU) abutments in immediate-loading dental implant protocols, focusing on implant survival, prosthetic and biological complications, and patient-reported outcomes. METHODS: PubMed and Scopus were searched for original English-language clinical studies published between 2001 and 2025, including RCTs, cohort studies, and clinical series with at least 12 months of follow-up. Only studies evaluating TiB and MU abutments in immediate-loading protocols were included. Due to heterogeneity in study designs, case selection, outcome measures, and follow-up duration, a narrative descriptive synthesis was performed without pooled statistical analysis. RESULTS: Seventeen clinical studies met the inclusion criteria. Both TiB and MU abutments showed high implant survival rates, generally in the high 90 s. TiB abutments performed well in single-tooth anterior restorations, showing fewer mechanical complications and better esthetic ratings. MU abutments were predominantly used in full-arch cases, demonstrating reliable long-term function but with higher mechanical maintenance needs. Marginal bone loss remained within acceptable limits across studies. Patient-reported outcomes were inconsistently assessed, though TiB tended to score higher for esthetics and MU for functional comfort. CONCLUSIONS: Both TiB and MU abutments effectively support immediate loading when primary stability and proper prosthetic planning are achieved. TiB may be preferable for esthetic single-tooth cases, while MU abutments remain suitable for full-arch rehabilitation. The limited number of head-to-head studies highlights the need for well-designed randomized trials with standardized outcomes and validated patient-reported measures.