The importance of inflammatory biomarkers, IL-6 and PAPP-A, in the evaluation of asymptomatic apical periodontitis

To examine the use of IL-6 and PAPP-A along with the new imaging for scoring methods to determine the severity of apical periodontitis (AP). The scoring of disease severity in 121 patients with AP, using dental radiographs, was based on "The Apical Periodontitis Grading Scale" (APGS), as those having 1 tooth with AP and severity of 3-4 were classified as grade 1 (mild); those having > 1 tooth and severity of 3-4 as grade 2 (moderate) and those with at least one tooth with a severity of 5 as grade 3 (severe). 45 systematically and orally healthy volunteers were selected as the control group (grade 0). Dental demographic data of all participants were recorded. Besides, venous blood samples were collected to study their complete blood count and levels of IL-6 and PAPP-A. Both NLR and PAPP-A levels of the grade 3 AP patients were found significantly higher than those of the control group and grade 1 and grade 2 AP patients (2.55 +/- 1.40 vs 1.98 +/- 1.05, 1.94 +/- 0.58 and 1.86 +/- 0.50; 0.606 +/- 0.211 vs 0.422 +/- 0.273, 0.447 +/- 0.224 and 0.436 +/- 0.242,p < 0.01, respectively). AP grades identified by the new scoring system were moderately correlated with IL-6 levels (Spearmanr = 0.4168,p < 0.001). The risk of patients with IL-6 levels above 12.5 pg/ml to develop AP (relative risk) was found to be 2.19 times higher than that in those with lower IL-6 levels (98% Cl 1.233-3.905,p < 0.0024). APGS classification suggested to determine AP severity was found to be significantly correlated with levels of inflammatory markers IL-6 and PAPP-A.