A comparison between mandibular overdentures retained by a single midline implant and by two implants: A systematic...

Mandibular edentulism presents significant oral health challenges, particularly in middle-aged and older adults. While implant-retained overdentures provide an effective treatment option, the optimal number of implants remains unclear. A single midline implant has been proposed as an alternative to conventional 2-implant systems, but their comparative clinical effectiveness remains uncertain.

This systematic review aimed to evaluate and compare the clinical effectiveness of single midline implant overdentures versus 2-implant overdenture systems in edentulous mandibles.

A comprehensive search of Cochrane, Embase, PubMed/Medline, and Web of Science databases was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies involving patients with edentulous mandible rehabilitated with overdentures were included. The primary outcome assessed was implant survival rate, while secondary outcomes included patient satisfaction, crestal bone loss, peri-implant parameters, prosthodontic complications, maintenance requirements, post-operative symptoms, muscular activity, and masticatory efficiency.

A total of 12 randomized controlled trials (RCTs) involving 517 participants (288 women and 229 men) aged between 53.3 and 67 years (mean:62.34; standard deviation:4.41) were included in this systematic review. Of the 517 enrolled participants, data from 471 were evaluated, indicating an overall drop-out rate of 8.89%. The findings suggest that single-implant overdentures offered a suitable alternative to conventional 2-implant overdentures in edentulous mandibles. Lower costs and the advantages of minimally invasive, flapless surgery were defining features of single midline implant overdentures. However, no significant differences were observed in terms of implant survival, crestal bone loss, or patient satisfaction.

Single-implant mandibular overdentures demonstrated similar implant survival and patient satisfaction outcomes to 2-implant overdentures in selected patient populations. However, the evidence was limited by the small number of RCTs, heterogeneous study designs, and relatively short follow-ups. Therefore, while single-implant overdentures may offer a suitable alternative in specific clinical contexts, current data are insufficient to support them as the universal minimum standard.