Purpose: Τo evaluate and compare the marginal bone loss (MBL), survival rates, and periodontal parameters of immediately loaded implants with either Dolder bar or Locator attachments placed in the interforaminal region of edentulous mandibles. Materials and Methods: A total of included 19 patients with edentulous mandibles each received two implants in the interforaminal area of the symphysis. Randomly allocated Dolder bar or Locator attachments were then attached immediately, and both clips and a framework were fastened to the denture by the dental laboratory within 24 hours. Results: A total of 28 subjects with 56 implants were treated in accordance with the immediate-loading study protocol. Of these, 9 patients were lost to follow-up; 1 patient reported a serious illness and 8 patients moved and couldn’t be reached. The 19 subjects not lost to follow-up (11 women and 8 men; average age: 68 years) were included. Every patient received either two Locator abutments and were assigned to group A (7 patients; 36.8%) or two multiunit abutments and were assigned to group B (12 patients; 63.2%). No implant failure was detected for either group, and therefore the survival rate for both groups was 100% after 5 years. After 5 years without any symptoms, 2 implants from group A and 7 implants from group B showed > 2 mm of MBL, which makes the group A success rate 85.7% and the group B success rate 70.8%. Modified sulcular bleeding index (mSBI) did not differ significantly at any of the measurement intervals. However, the modified plaque index (mPI) of group B was significantly higher than group A at the 60-month follow-up. Conclusion: It can be concluded that either splinting or not splinting the immediately loaded interforaminal implants to retain mandibular overdentures (OVDs) does not affect marginal bone levels after 5 years and immediate loading of nonsplinted implants with Locator attachments can be safely preferred to retain mandibular OVDs.