Background: Animal research is conducted to understand the causes and treatments of human diseases. Clinical human studies may not, however, be able to replicate results previously obtained from animal experiments.
Aim: to assess whether or not peri-implantitis therapies conducted in animal experiments were successfully replicated in human clinical trials.
Materials and methods: Dental journals classified by citation impact factor were searched in the Journal Citation Reports database for animal trials on treatment of peri-implantitis between 1992 and 2008. It was assumed that prominent findings from high-ranked journals would be more likely to be tested in subsequent human clinical trials. A second literature search was conducted in the Pubmed, Cochrane, and Lilacs databases to identify potential human studies that repeated or replicated animal experiments. Controlled trials and case-series were included in the analysis. Because of the heterogeneity of the studies (e.g., different study designs and different outcome measures), only descriptive analysis was undertaken.
Results: Of 1199 studies retrieved, 53 (23 animal and 30 human studies) were selected for the review. Because no animal experiment and human trial had comparable study procedures, precise determination of the success of replication from animal experiments in clinical trials was not possible. Overall, the study characteristics were extremely heterogeneous.
Conclusions: To reduce the great heterogeneity between animal and human studies on peri-implantitis, researchers should pay attention to standardization of research procedures. Power analysis and sample-size calculation in animal experiments and human trials should be always considered when planning a research study.