Comparative prosthetic outcomes of two bar attachment systems in mandibular two-implant overdentures: A 5-year pilot...

Mandibular two-implant overdentures represent the standard of care for edentulous patients; however, long-term evidence comparing prosthetic maintenance demands among different bar attachment systems remains limited. This pilot randomized clinical study aimed to compare the 5-year prosthetic complications and maintenance profiles of bar-locator versus bar-clip attachments to inform clinical attachment selection.

Sixteen completely edentulous patients were rehabilitated with new maxillary and mandibular complete dentures and received two implants placed in the mandibular canine regions. Participants were randomly allocated to either a bar-locator group (n = 8) or a bar-clip group (n = 8). Prosthetic complications, including retentive component wear, screw loosening, tooth wear, denture fracture, relining, and other maintenance events, were clinically recorded over a 5-year follow-up period.

All participants completed the 5-year follow-up (100% retention). A total of 24 prosthetic complications were recorded in the bar-locator group and 13 in the bar-clip group. The mean number of complications per patient was 3.0 ± 1.3 for bar-locator and 1.6 ± 0.9 for bar-clip overdentures (absolute risk difference = +1.4; 95% CI: -0.3 to 3.0). Although the bar-locator group demonstrated numerically higher frequencies of retentive insert wear, tooth wear, and minor fractures, none of the between-group differences reached statistical significance (p > 0.05). No catastrophic mechanical failures were observed in either group.

Over 5 years, both bar-locator and bar-clip attachment systems demonstrated reliable mechanical performance and clinical longevity. The bar-locator system was associated with a higher overall maintenance burden. In contrast, bar-clip overdentures required relining more frequently, reflecting distinct long-term maintenance profiles rather than differences in durability. These pilot findings support the feasibility of a larger randomized trial and highlight the need for future studies incorporating patient-reported outcomes, cost-effectiveness analyses, and time-to-event assessments of prosthetic maintenance.