Purpose <p>To retrospectively evaluate biological and technical complication rates of implant-supported fixed complete dentures (IFCDs) in edentulous jaws and to identify factors associated with complications over long-term follow-up.</p> Methods <p>Between 2003 and 2023, 91 IFCDs supported by 498 implants were placed in 72 patients. Mean observation period was 6.8 years (0.5–17). Biological and technical complications were compared between materials. Time until first complication was estimated using Kaplan–Meier analysis and risk factors for recurrent complications were assessed through multivariable Andersen–Gill Cox regression.</p> Results <p>Seven IFCDs failed, corresponding to a cumulative overall IFCD survival of 92.3%. Twenty-one of 498 implants (4.2%) were explanted. Overall prosthesis survival of resin veneered (RV) and ceramic veneered (CV) IFCDs did not differ (<i>p</i> = 0.85), whereas veneer fracture–free survival was significantly higher for CV IFCDs (<i>p</i> = 0.0094). In total, 169 complications were recorded, including recurrent events, whereas 49.5% of prostheses remained complication-free. Technical complications predominated, with veneer fractures representing the most frequent event. Biological complications such as peri-implantitis and implant loss occurred less frequently. Compared to base metal alloy–ceramic IFCDs, titanium–resin IFCDs exhibited a significantly higher overall complication risk (HR 4.25, <i>p</i> = 0.0015), particularly for veneer fractures (HR 7.11, <i>p</i> = 0.0029).</p> Conclusions <p>Within the limitations of this long-term retrospective cohort study, IFCDs demonstrated high prosthesis and implant survival rates, but a considerable number of predominantly technical complications. The choice of framework and veneering material appears to influence long-term complication risk and should be carefully considered during treatment planning.</p> Graphical abstract <p></p>