Influence of interleukin genetic polymorphism on apical periodontitis in human patients: A comprehensive review
We examined the influence of interleukin genetic polymorphisms in individuals with apical periodontitis (AP). Based on the PICO strategy, searches were conducted in PubMed, SciELO, Web of Science, Medline, LILACS and EMBASE databases to answer a guiding question. The quality of studies and methodological rigor were assessed using the Critical Appraisal Skills Program Checklist and classification made according to levels of evidence. The search identified 292 studies, of which six were included based on the criteria. All evaluated the IL-1β polymorphism, of which three found a significant association with a protective and/or potentiating effect of IL-1β on AP. Two studies evaluated the IL-6 polymorphism, one of which identified a significant association. Three studies evaluated TNF-α polymorphism, of which two reported significant associations with AP. An association was also found in one study for IL-8 with AP. In conclusion, polymorphisms of several interleukins have been found to influence the risk and development of AP in humans. Some polymorphisms are more influential and have been more intensively studied than others, such as interleukin 1-β, followed by IL-6 and TNF-α. This influence of genotype can be expressively or mildly marked. Individuals presenting one or two copies of a particular allele appear to be at higher risk of developing periapical lesions. These apparent associations of interleukins with AP merit further study.