Experimentally induced peri-implantitis: a review of different treatment methods described in the literature.
The aim of this article was to present the experimental peri-implantitis models described in the literature and to provide a review of currently used treatment methods. For this purpose, 29 English- and German-language studies published in internationally reviewed journals were examined for similarities and differences regarding animal models, types of implants, and methods used for inducing peri-implantitis. In almost all studies, the implants were located in the mandible, which suggests that peri-implantitis of the maxilla has been researched very little. While in most studies, peri-implantitis was induced by means of ligature and plaque accumulation, only 3 studies have been published that attempted to induce peri-implantitis by means of mechanical overload. Of the latter, only one author observed peri-implant bone resorption. Eleven studies reporting on ligature-induced peri-implantitis presented enough data to be subjected to further statistical data analyses. Meta-analysis revealed that the period of ligature application, and thus the duration of plaque accumulation, generally had no influence on the resultant depth of the bone defect. However, when screw-type and cylindric implants were analyzed separately, a weakly significant positive effect of the duration of ligature application on the resultant defect depth was determined for cylindric implants (P = .092). This could imply that smooth screw-type implants were less susceptible to ligature-induced peri-implant inflammation. Regenerative treatment methods included the membrane technique using non-resorbable membranes (guided bone regeneration), augmentation with autogenous bone, augmentation with bone substitute materials (hydroxyapatite or demineralized freeze-dried bone) or with recombinant human bone morphogenetic protein-2, and a combination of membrane and augmentation procedures. While all described methods resulted in acceptable bone gain, it seems to be difficult to achieve new osseointegration (reosseointegration) of treated implants. Of all tested treatment methods, the combination of guided bone regeneration and augmentation with demineralized freeze-dried bone resulted in the most favorable results regarding bone gain and reosseointegration.