Comparative evaluation of retentive capacity of three different attachment systems for implant retained overdentures: An in vitro study.

Background: The primary issue in managing edentulous patients is the severely resorbed mandibular ridge, particularly in older individuals with diminished adaptive capacities. This compromised situation leads to the fabrication of inadequate dentures that lack retention and stability, potentially causing psychosocial issues.

Aim: To determine the difference in retentive capacity between three attachment systems in implant-retained overdentures.

Methods: Three edentulous mandibular models were fabricated using heat-cured polymethacrylate resin, with two implant replicas placed in the intra-foraminal region of each model. 30 acrylic resin mandibular overdentures were fabricated with provisions for three different overdenture attachment systems: A prefabricated ball/O-ring attachment, a locator attachment system, and an equator attachment system. Each model was subjected to 15000 pulls using a universal testing machine to remove the overdenture from the acrylic model and the force data were recorded.

Results: The ball/O-ring attachment system demonstrated superior retentive capacity for 15 years, while the locator and equator attachment systems maintained excellent retentive capacity for 5 years.

Conclusion: The ball/O-ring attachment system outperformed better than the other two attachment systems regarding retentive capacity. The locator and equator attachment systems presented sufficient retentive abilities until 15000 cycles. After 7500 cycles, significant differences in retentive force between the systems evolved.