Estudo Retrospectivo Longitudinal com Acompanhamento de 13 Anos de Overdentures Mandibulares Retidas por O-ring

Abstract

Research question: Does the angulation between mandibular implants influence the need for prosthetic maintenance in O-ring–retained overdentures, and does it affect patients’ quality of life and perception? Introduction: The influence of interimplant angulation on the prosthetic maintenance of O-ring–retained mandibular overdentures, as well as its potential impact on quality of life and patient perception, remains unclear in long-term clinical studies. Objective: To evaluate whether interimplant angulation influences prosthetic maintenance in O-ring– retained mandibular overdentures and to analyze its relationship with patients’ quality of life and self-perception. Materials and Methods: This longitudinal retrospective study (2012– 2025) analyzed records of patients rehabilitated with mandibular overdentures retained by two implants (n = 35). Interimplant angulation was measured radiographically and analyzed as a continuous variable. The number of O-ring replacements and prosthetic adjustments during follow-up were recorded. Quality of life and patient perception were assessed using the OHIP- EDENT and SATO instruments in a chairside sub-sample (n = 20). Associations among variables were analyzed using non-parametric tests, specifically Spearman’s correlation coefficient, with a significance level of 5%. Results: The most frequent prosthetic maintenance event was O-ring replacement, with an approximate mean frequency between 0.5 and 1.0 replacement per year of use. Statistical analysis showed no significant association between implant angulation and the number of O-ring replacements or the need for prosthetic adjustments (weak correlation; |ρ| < 0.30; p > 0.05). In the evaluated sub-sample, prosthetic satisfaction scores (SATO) were high, predominantly ≥ 85, while quality-of-life scores (OHIP- EDENT) indicated low negative impact, with no significant correlation with the degree of implant angulation (p > 0.05). Conclusion: O-ring–retained mandibular overdentures demonstrated long-term functional stability, predictable maintenance needs, and no significant influence of implant angulation on clinical performance over the evaluated period. Clinical Implications: These findings support O-ring–retained mandibular overdentures as a reliable therapeutic option, even in the presence of small angular variations between implants, and provide practical guidance for treatment planning, clinical execution, and patient counseling regarding longevity and maintenance.