Endosseous implants present high survival rates within a 10-year observation time; however, implant failure and biologic complications are not completely avoidable. Although specific bacteria, dental plaque, and environmental factors are associated with peri-implant disease, there are currently no reliable predictors of peri-implantitis occurrence and severity. Disagreement about which clinical measures of peri-implant health are of diagnostic value continues because of the complexity of the disease process. Thus, identification of genes that control or modify aspects of the host response may provide a method to identify individuals at an elevated risk for peri-implant infections. Elevated levels of the inflammatory cytokine interleukin-1 (IL-1) in the crevicular fluid around diseased implants seem to play an important role in the pathogenesis and severity of peri-implantitis. The purpose of this review article was to critically address the genetic associations regarding IL-1 genotype claimed for peri-implant disease and to validate the use of IL-1 genetic susceptibility tests. It was revealed that the diagnostic value of both IL-1 genotyping and genetic tests for peri-implantitis should be reconsidered before altering treatment planning, regimens, and maintenance in implant dentistry. Schlagwörter: genotype, host response, interleukin-1, peri-implantitis, susceptibility