Long-term outcomes of single-implant mandibular overdentures: a 8-10 year prospective study across two cohorts

Abstract

Objectives This study aimed to evaluate the long-term outcomes of two prospective cohorts of edentulous individuals treated with single implant mandibular overdentures (SIMO) opposed by a conventional maxillary complete denture. Material and Methods A total of 74 participants, treated between 2013 and 2016 at the School of Dentistry of the Federal University of Goiás, Brazil, were included. A single midline implant was placed in the edentulous mandible; 93.2% of implants were immediately loaded, and outcomes were followed for 8–10 years. Data collected included dental patient-reported outcomes (dPROs), implant survival, implant stability, peri-implant health, and incidence of prosthodontic events. The frequency of the prosthetic maintenance and complication events was reported in terms of cumulative incidence. Within-group longitudinal changes were tested using paired comparison tests. A significance level of p < 0.05 was used for statistical inferences. Results Significant improvements in OHIP-Edent and satisfaction scores were observed immediately post-treatment and maintained throughout the follow-up period, confirming a significant positive effect of SIMO on these outcomes (p < 0.001). The overall implant survival rate was 95.6%. Peri-implant outcomes showed favorable health status, with mild bone loss observed (−1.55 ± 1.09 mm at the 8–10-year follow-up). Prosthetic complications and the need for recall visits for maintenance were common. The most frequent prosthetic complications were matrix replacement (43.3%) and overdenture fracture (12.4%). Conclusions SIMO demonstrated sustained long-term effectiveness with regular clinical monitoring and frequent maintenance. For most patients, the positive initial outcomes continued for up to 10 years, suggesting SIMO particularly benefits older patients with financial constraints.