Advances in Implant-Supported Overdentures: A Review of Recent Attachment Systems

Edentulism continues to present significant challenges in prosthodontic care, with conventional complete dentures (CDs) often failing to provide adequate retention and stability, particularly for the mandible. Implant-supported overdentures (ISODs) have transformed the rehabilitation of edentulous patients by bridging the gap between traditional removable prostheses and fixed implant restorations, offering enhanced stability, retention, and masticatory function while maintaining cost-effectiveness. The McGill consensus established the two-implant mandibular overdenture as the first-choice standard of care for edentulous mandibles. For maxillary cases, anatomical limitations typically necessitate a minimum of four implants. The success of ISOD treatment depends critically on appropriate attachment system selection, considering factors such as available inter-arch space, implant angulation, and maintenance requirements. This article aims to provide a comprehensive review of ISODs, exploring the evolution of attachment systems from early ball and bar designs to contemporary compact systems, including Locator, Locator R-Tx (Zest Dental Solutions, Carlsbad, CA, USA), and OT Equator (Rhein83 S.r.l., Bologna, Italy) attachments. Each system's specific advantages, limitations, space requirements, tolerance to implant divergence, maintenance protocols, and common complications are examined, emphasizing the importance of systematic follow-up care for long-term success.