Relationship between interleukin 1 (IL-1) genetic polymorphism and periimplantitis: systematic literature review and meta-analysis.

Periimplantitis (PI) is a complex multifactorial chronic disease caused by interactions between bacteria, host immune-inflammatory responses, and genetic or environmental factors that modify buccal eutrophism. In daily clinical practice, an increase in the prevalence of PI (8%) determined the need to establish the PI causes and set optimal therapeutic strategies. The interleukin family (IL-1), a group of cytokines, triggers and perpetuates peri-implantitis. Therefore, they could be used as biomarkers for diagnosis and treatment. This systematic review aimed to analyze the correlation between IL-1 allelic polymorphism (IL-1A -889, IL-1β -511, IL-1β +3954) and the PI disease. Selected databases were PubMed, Scopus, and Cochrane Library. The search strategy included the following terms: "dental implants"; "periimplantitis"; "interleukin-IL-1"; "polymorphism"; "perimplant bone loss". Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. A meta-analysis was conducted on five of 40 review articles. p-values, confidence intervals (CI), and Odds ratios (OR) were assessed. In 4 articles, the p-value was lower than 0.05, confirming the statistical significance of the result. The prevalence of the selected studies reported the existence of a causal association between polymorphisms of IL-1 and the onset of peri-implantitis, especially for IL-1 allelic variants associated with further polymorphic genes encoding for IL-6, tumor necrosis factor-alpha (TNF-α), matrix metalloproteinases (MMP)-8, IL-1Na, IL-8, IL-18, osteopontin (OPN). In addition, the presence of the IL-1 polymorphism and PI is particularly higher in smokers, diabetes, and autoimmune disease patients. The detection of salivary biomarkers is, therefore, a diagnostic tool with a high potential to intercept the PI early and act with appropriate and non-invasive treatment. Due to the continued technological innovation in biomarkers and diagnostic sciences, further studies are needed to investigate the role of these biochemical mediators. The results of studies and the recent technological innovation in biomarkers and diagnostic sciences will allow further research to investigate the role of these biochemical mediators.