A retrospective evaluation of 24 subjects treated with one-piece (1P) (n = 34) and two-piece (2P) (n = 38) implants placed in contralateral mandibular premolar locations was conducted. Cumulative implant survival was 100% following a 5-year (range = 59.9-72.3 months; mean = 63.1 months) postrestoration monitoring period. Bone loss (P = .1952) and prosthetic complications (P = .3667) did not significantly differ between the two groups. Clinical efficacy was equivalent for both implant designs.