Expression of biological markers in gingival crevicular fluid of teeth with orthodontically induced root resorption

Aim The goal was to investigate interleukin-1 receptor antagonist (IL-1ra) and dentin sialophosphoprotein (DSPP) levels in gingival crevicular fluid (GCF) as potential biomarkers for orthodontically induced root resorption (OIRR) using enzyme-linked immunosorbent immunoassay (ELISA). Materials and methods In all, 74 subjects were assigned to one of three groups: (1) orthodontic group included orthodontic patients who showed radiographic evidence of 1-3 mm root resorption of a maxillary central incisor, (2) pediatric group included pediatric patients who showed radiographic evidence of physiologic root resorption of a lower second primary molar, and (3) control group included subjects who had no orthodontic treatment and showed no radiographic evidence of root resorption. Samples from the GCF were collected with endodontic absorbent paper points inserted 1 mm below the gingival margin of the tooth. The IL-1ra and DSPP levels were evaluated using ELISA. Results The IL-1ra levels were 657.5 +/- 51.5, 319.9 +/- 181.3, and 129.4 +/- 54.9 pg/ml for the control, orthodontic, and pediatric groups, respectively. The DSPP levels were 1.6 +/- 1.0, 30.1 +/- 9.6, and 39.2 +/- 3.3 pg/ml for the control, orthodontic, and pediatric groups, respectively. Post hoc analyses revealed significant differences for IL-1ra and DSPP between any two groups. Sensitivity and specificity of IL-1ra for the diagnosis of OIRR showed 80% reliability and a cutoff value of <= 432.6 pg/ml, while the analysis of DSPP showed 100% reliability and a cutoff value of >= 7.33 pg/ml. Conclusions The levels of IL-1ra and DSPP detected in the orthodontic and pediatric groups indicate a possible association with OIRR. Efforts to develop tests for screening, diagnosis, and monitoring OIRR based on biological markers should continue.