Single nucleotide polymorphisms as a predisposing factor for the development of apical periodontitis—An umbrella review

Background: The interaction between heredity and different environmental factors in the modification of apical periodontitis (AP) susceptibility and prediction of its progression remain poorly elucidated. Objectives: This umbrella review aimed to (i) analyse the available relevant systematic reviews in an attempt to determine the association between genotype and allelic distribution of different single-nucleotide polymorphisms (SNPs) and the development of AP, (ii) report deficiencies and gaps in knowledge in this area and (iii) present recommendations to conduct future clinical studies and systematic reviews. Methods: A literature search was conducted using Clarivate Analytics' Web of Science, Scopus, PubMed and Cochrane Database of Systematic Reviews, from inception to October 2021, with no language restrictions, including a grey literature search. Systematic reviews with/without meta-analysis evaluating genotype and allelic distribution of different SNPs between adult patients with/ without AP were included. All other type of studies were excluded. The methodological quality was assessed using the A MeaSurement Tool to Assess systematic Reviews (AMSTAR)-2 tool. Two independent reviewers were involved in study selection, data extraction and appraising the included reviews; disagreements were resolved by a third reviewer. Results: The current study includes five systematic reviews. Three reviews performed meta-analysis. Three reviews were graded by AMSTAR 2 as ‘critically low’ quality, whereas the other two were graded as ‘low’ and ‘moderate’ quality. Two reviews indicated that carriers of specific genotypes and alleles of tumour necrosis factor-alpha (TNF-α) -308 G > A and interleukin 1-beta (IL-1β) + 3954 C/T gene polymorphisms are more susceptible to an acute and persistent form of AP. However, high heterogeneity was observed. Discussion: The statistical heterogeneity within included systematic reviews was a consequence of clinical and methodological diversity amongst primary studies. Although some of the included reviews suggested that carriers of specific genotype and/or allele of TNF-α −308 G > A and IL-1β + 3954 C/T SNPs are more susceptible to AP, their conclusions should be interpreted with caution. Conclusions: No candidate genes could be identified as a definitive genetic risk or protective factor for the development and progression of AP, and further high-quality genome-wide association studies are warranted.