A 5-year randomized trial to compare 1 or 2 implants for implant overdentures

The hypothesis of this 5-y randomized clinical trial was that there would be no significant difference in the satisfaction of edentulous participants with removable complete overdentures attached to 1 or 2 mandibular implants. secondary aims were to test changes in satisfaction between and within the groups from baseline to 5 y and differences between the groups in implant survival and prosthodontic maintenance over 5 y. each of the 86 participants (mean age,67 y) was randomly allocated to receive either 1 implant in the midline (group 1) or 2 implants in the canine areas (group 2) attached to a mandibular overdenture opposing a maxillary complete denture. satisfaction was self-assessed by participants on a visual analog scale at baseline prior to implants,as well as at 2 mo and 1,3,and 5 y with implant overdentures,whereas implant survival and prosthodontic maintenance were assessed by clinical examination. after 5 y,29 participants in group 1 and 33 in group 2 were available,with most dropouts due to death. satisfaction with the implant denture after 5 y was significantly (p < 0.001) higher than at baseline in both groups and remained with no significant difference (p = 0.32) between the groups. no implants failed in group 1 but 5 failed before loading in 4 participants in group 2. most participants required maintenance or occasionally denture replacement,and although differences between the groups were not statistically significant,group 1 experienced almost twice as many fractured dentures usually adjacent to the implant attachment. we conclude that there were no significant differences after 5 y in satisfaction or survival of implants with mandibular overdentures retained by 1 implant or 2 implants. additional research is required to confirm long-term treatment effectiveness of single-implant dentures and the implications of prosthetic maintenance with implant overdentures (clinicaltrials.gov: nct02117856). © international & american associations for dental research 2014.