Flapless Mini Implants Immediately Loaded for Full-Arch Overdenture Rehabilitation: An Up-To-15-Year Retrospective Study

Objectives: This study aimed to evaluate the survival rates of Mini Dental Implants (MDIs) placed in both the maxilla and the mandible, and their associated overdenture prostheses in edentulous patients over short-, medium-, and long-term follow-up periods. Materials and Methods: Patients rehabilitated with Mini Dental Implants (diameter ≤ 2.9 mm) as support for overdenture prostheses with a minimum follow-up period of 3 years were included in the study. Data from eligible patients were collected, and marginal bone loss (MBL) was assessed for each implant. The primary outcomes for the prostheses and implants included failure rates, complications, and implant-related MBL. Results: The study analyzed 83 patients and 334 implants over an 8.09 ± 3.96-year mean follow-up. The cumulative implant survival rate at 15 years was 86.3% (95% CI: 79.5%–91.0%). Mean MBL increased from 0.09 ± 0.44 mm at implant placement to 1.79 ± 0.82 mm at 15 years, with Lodi Biomax implants exhibiting significantly lower annual bone loss compared to Dentatus Atlas implants (p < 0.001). The prosthetic survival rate was 95.45% (95% CI: 91.1–99.81). Longer follow-up (p = 0.018) and fewer adjustments (p < 0.001) reduced risks of complication occurrence. Additionally, Lodi Biomax implants had fewer complications compared to Dentatus Atlas (p = 0.039). Conclusion: Mini Dental Implants with a diameter between 2.4 and 3 mm showed high survival rates over follow-ups of up to 15 years. Their use offers a viable prosthetic solution for edentulous patients, minimizing surgical invasiveness, rehabilitation time, and costs, particularly when a fixed prosthesis is either not feasible or not requested by the patient.