Purpose: To clinically evaluate a recently developed, standardized, three-implant-supported full-arch treatment concept for fully edentulous mandibles. Materials and Methods: This ongoing multinational prospective cohort study is evaluating the performance of the treatment concept over 5 years in patients who were fully edentulous or had failing dentition of the mandible. The primary outcome was the cumulative survival rate of implants (CSRI). Secondary outcomes included the cumulative survival rate of the prostheses (CSRP), marginal bone level change, soft tissue outcomes, impact on quality of life, and patient and clinician satisfaction. The 1-year report is presented here. Results: In total, 110 patients (330 implants) were included. Prostheses underwent immediate loading in 76.4% of cases and early loading in 23.6% of cases. The mean surgical time was 1.60 ± 0.78 hours, and the mean laboratory time was 3.99 ± 1.74 hours. At 1 year, eight implants and three prostheses failed, yielding an implant-level CSRI of 97.5% and a CSRP of 97.3%. All prosthetic failures were due to loss of two implants in the patient. The mean marginal bone level change at 1 year was -0.62 ± 1.39 mm. Among soft tissue outcomes, the Bleeding Index improved significantly between the 6-month and 1-year follow-up, and 242 implants (75%) were surrounded by keratinized mucosa by the 6-month follow-up. Patients reported a significant improvement in quality of life between prosthesis placement and the 6-month follow-up based on the Oral Health Impact Profile for Edentulous 21 questionnaire. Both patient and clinician satisfaction with function and esthetics were high throughout treatment. Conclusion: This novel treatment concept using a passively fitting standardized framework with simplified surgical and prosthetic workflow demonstrated high survival and excellent outcomes at 1 year while reducing chair and fabrication time. This concept may offer patients a safe and efficient option for fullarch mandibular prostheses. Keywords: dental implants, edentulous, efficient, failing, mandible, terminal dentition, Trefoil