To investigate the impact of the retention system (screwed or cemented) of implant fixed dental prostheses (i-FDPs) on the peri-implant health, prosthesis' state, patient self-evaluation of functionality and aesthetics, and oral health-related quality of life (OHRQoL).35 participants were classified into two groups according to the retention system of their metal-ceramic i-FDPs. For the analysis of peri-implant health and prosthetic complications, the implant units were individually assessed. Group 1 (SPD; n = 22): implant units for screwed i-FDPs; and Group 2 (CPD; n = 36): implant units for cemented i-FDPs. Data related to socio-demographics, design and installation of the superstructures, peri-implant condition, prosthetic complications, functionality, and aesthetics, were gathered. Patients answered the Oral Health Impact Profile (OHIP-14sp) questionnaire. Descriptive and parametric probes were run to evaluate the impact scores considering the study variables (α = 0.05).The plaque index, gingival index, functionality, aesthetics, and global evaluation made by the patient recorded significantly better results for the SPD group. The most affected OHIP-14sp domain was 'Physical pain', followed by 'Psychological discomfort', and 'Functional limitation'. The subscales: 'Functional limitation', 'Physical disability', and 'Social disability', attributed significantly worst OHRQoL to CPD users.A major presence of peri-implant disease, together with a worse functionality, aesthetics, and patient satisfaction were recorded in cemented i-FDPs with respect to the screwed ones.The retention system of i-FDPs can impact the peri-implant health, the subjective functional and aesthetic evaluation of the restoration, and the patients' OHRQoL; the screw retention providing superior results than the cementation.