Biological Markers in the Associated with External Invasive Resorption: A Split-Mouth Cross-Sectional Study

Introduction: This study aimed to investigate the levels of interleukin-1 receptor antagonist (IL-1RA), receptor activator of nuclear factor-kB ligand (RANKL), osteoprotegerin (OPG), interleukin-1(3, osteopontin, and tissue necrotizing factor-a in teeth with external invasive resorption (EIR) in comparison to the contralateral healthy tooth of the same patient. Methods: Twenty-nine patients with at least one tooth with EIR and a healthy tooth on the contralateral side (33 paired teeth) were included. Data on patient demographics and medical and dental history were collected. Gingival crevicular fluid was collected from the subject and control teeth. Clinical, radiographical, and cone-beam computed tomography examinations were performed. Wilcoxon signed-rank test was used to compare biomarker concentrations, RANKL/OPG, and IL-1RA/interleukin-1(3 ratios in the diseased and healthy teeth. Teeth pairs were grouped based on Heithersay and Patel's classification, and the differences in biomarker concentrations between diseased and healthy teeth were compared using a Kruskal-Wallis test. Results: Teeth with EIR had significantly lower concentrations of IL-1RA and OPG compared to their respective healthy control teeth (P < .05). The RANKL/OPG ratio in teeth with EIR was significantly higher than in their paired healthy teeth (P < .05). A history of herpes zoster infection was associated with a higher IL-1RA concentration and RANKL/OPG ratio (P < .05). Orthodontic treatment was significantly associated with lower OPG concentration (P < .05). Conclusions: There is a significant association between EIR and specific biological markers. A history of orthodontic treatment and herpes zoster infection are significantly associated with altered levels of biomarkers in the gingival crevicular fluid. (J Endod 2025;51:150- 156.)