Ultrashort (4-mm) Implants with Immediate Loading for Mandibular Full-Arch Rehabilitation in Frail Patients of a Retrospective Cohort: A 10-Year Follow-Up

Abstract

Background: The management of complete mandibular edentulism in frail patients with severe bone atrophy is a clinical challenge. Ultrashort implants (≤4 mm) have been proposed as a minimally invasive alternative to bone augmentation procedures; however, long-term evidence in full-arch rehabilitations remains limited. Methods: This retrospective single-center cohort study presents the 10-year follow-up of patients treated with full-arch mandibular rehabilitation under immediate loading supported by 4 mm ultrashort implants. Patients were originally treated between 2015 and 2017. The primary outcome was prosthetic success at 10 years, defined as a stable and functional prosthesis supported by four implants. Secondary outcomes included implant survival, timing of implant loss, and biological and prosthetic complications. Results: Fourteen patients were available for evaluation at the 10-year follow-up. The success of the prosthetic structure was 100%, with all patients maintaining stable and functional rehabilitation. As regards the implants, a total of 82 implants had been placed, with 14 implant losses, resulting in a cumulative implant survival rate of 82.9%. Implant losses occurred mainly in early (1 week, 4 months) and late phases (between 3 and 10 years), while no losses were observed between 1 and 3 years. Overall, 71.43% of patients experienced at least one implant loss; however, this did not compromise prosthetic function. Conclusions: In this retrospective cohort, all full-arch prostheses remained functional at 10 years, although cumulative implant survival was 82.9%. These findings suggest that rehabilitation supported by 4 mm ultrashort implants may represent a treatment option for carefully selected frail patients with severe mandibular atrophy. Prospective controlled studies are needed to confirm these findings and compare this approach with standard-length implants and bone augmentation procedures.