Matthys C, et al. - In this 5-year clinical comparative study, researchers compared the differences between ball and locator 2IOD with respect to the prosthetic maintenance (complications) and technical outcome, as well as analyzing the impact of both treatment modalities on the oral health related quality of life (OHRQoL) and the implant outcome. This investigation was conducted in a dental clinic in Enschede, the Netherlands. For this comparative clinical cohort study, 90 edentulous people were treated with balls (n = 34) or locator (n = 56). Data reported that 5 years of implant survival, regardless of attachment, was 98.7%. Five years maintenance-cost, regardless of attachment, was 11% of the initial cost. According to findings, balls and locators produce stable 5-years implant result and improved OHRQoL. Locators needed more maintenance, resulting in reduced retention. Maintenance costs are minimal, but OHRQoL can be affected by study abutments at least.