Lack of association between overload and peri-implant tissue loss in healthy conditions.

Data sourcesPubMed, Ovid, EMBASE and LILACS were searched up to December 2011. In addition, the reference lists of the selected review papers were further hand searched. Language was limited to studies published only in English.Study selectionHuman and animal randomised clinical trials (RCT), systematic reviews of RCTs, non-randomised trials, case series that reported on the clinical, radiographic, and/or histological outcomes of dental/oral implants exposed to excessive load were considered eligible for inclusion.Data extraction and synthesisIdentified studies were evaluated by one non-blinded reviewer according to the selection criteria. When doubt arose co-authors assisted until consensus was reached. The data extracted from the clinical studies included study design, patients/implants/prostheses/loading time/follow-up time, type of intervention/methods, outcome, and, specific to animal studies, the animal model, intention to overload (ie yes or no), load mode, type of loading (ie dynamic or static), and microbial control if any. The heterogeneity among studies did not allow data to be combined.ResultsThe search strategy in addition to hand searching retrieved 726 potentially eligible studies after de-duplication. After screening the 41 full-text relevant studies and applying the selection criteria assessment, only three non-randomised split-mouth animal studies and one systematic review of animal experimental data were considered for inclusion. The non-randomised studies could not reveal any relationship between increased leverage on dental implants and marginal loss. The systematic review suggested that supra-occlusal contacts on uninflamed peri-implant bone tissue did not cause catabolism, whereas supra-occlusal contacts combined with inflammation significantly increased the plaque-induced catabolism.ConclusionsThe effect of implant overload on bone/implant loss in clinically well-integrated implants is poorly reported and provides little unbiased evidence to support a cause-and-effect relationship.