BACKGROUND Different factors can affect prosthetic maintenance requirements for mandibular implant overdentures (IODs). However, the literature shows a high level of disagreement concerning the effect of each factor on maintenance needs. OBJECTIVE The purpose of this systematic review was to address the focus question: "In the clinical studies published since 2004 of adult patients with totally edentulous mandibles treated by IODs with a variable number of implants and different designs, what were the maintenance types, frequencies, and complications?" METHODS A search of MEDLINE and PubMed databases was performed targeting papers in English on prosthetic maintenance of mandibular IODs published between 2004 and June 2015, aiming at recognizing the needs for adjustment, repair, and renewal. The recorded data were divided into 6 categories, and a percentage value was attributed to each. RESULTS From a total of 130 articles, 33 studies met the specified inclusion criteria for the review (14 randomized controlled trials, 8 prospective clinical trials, 3 retrospective studies, and 4 systematic reviews). These articles provided evidence that a mean complication rate was impossible to determine because of the multiplicity of contributing factors. No clear identification of the causes of mechanical complications was found, nor was there any clear evidence of superiority of one implant and/or attachment design over another. CONCLUSIONS Prosthetic complications with IODs are unavoidable. However, they can be reduced to an expected level if a close follow-up protocol is implemented aiming at anticipating risks of unexpected complications. Further clinical studies are needed to achieve a constructive meta-analysis that accounts for different parameters such as opposite arch, attachment functional variety, connection method, and prosthesis quality.