Tumor Necrosis Factor Alpha-308 G/A Single-Nucleotide Polymorphism and Apical Periodontitis: An Updated Systematic Review and Meta-analysis

Introduction: This study aimed to perform a more precise estimation of the association between tumor necrosis factor alpha (TNF-alpha) 2308 G/A single-nucleotide polymorphism (SNP) and the risk of development of apical periodontitis (AP) and its phenotypes based on all available published studies. Methods: The study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and is registered in PROSPERO (CRD42020176190). The literature search was conducted via Clarivate Analytics Web of Science, Scopus, PubMed, Cochrane Central Register of Controlled Trials, and China National Knowledge Infrastructure databases from inception to December 2020 with no language restrictions. Two reviewers were involved independently in the study selection, data extraction, and appraising the studies that were included. The quality of the included studies was evaluated using the Strengthening the Reporting of Genetic Association and the Grading of Recommendations Assessment, Development and Evaluation system. The frequencies of the genotypes and alleles of the TNF-alpha (G>A 308, rs1800629) gene with 95% odds ratio were used. Results: Four studies met the inclusion criteria with moderate risk of bias. This study revealed no significant association between TNF-alpha 2308 G/A SNP and AP and the risk of AP development. Moreover, there was no significant association between genotype or allele frequency distribution and clinical manifestations (acute vs chronic) of AP. The certainty of evidence per the Grading of Recommendations Assessment, Development and Evaluation system was very low. Conclusions: Because of very low certainty of evidence, whether there is an association between TNF-alpha 2308 G/A SNP and AP warrants further well-designed multicentric studies to adjudicate a better understanding of the role of genetic factors in the etiopathogenesis of AP.