Biological markers for evaluation of root resorption

BackgroundExternal apical root resorption is a pathologic consequence of orthodontic tooth movement. Cementum and dentin are removed from the root surface while active force is present.ObjectiveThe aim of this study was to identify and quantify extracellular matrix proteins, dentin matrix protein 1 (DMP1), dentin phosphophoryn (PP), and dentin sialoprotein (DSP) in the gingival crevicular fluid (GCF) of subjects undergoing orthodontic treatment.MethodsSubjects with mild (less than 2 mm) and severe (more than 2 mm) root resorption during orthodontic treatment were identified by radiographs. A control group of subjects with neither signs of root loss nor undergoing orthodontic treatment was also identified. GCF was collected from the upper incisors by using filter paper strips (Periopaper). The absorbed GCF was eluted and the proteins were separated by SDS-PAGE analysis and stained. Western blot and ELISA were also performed. One-way ANOVA and Scheffé test were used for statistical analysis.ResultsSDS-PAGE analysis identified proteins at 77, 66, 55, 50 and 26 kDa. Immunoblotting did not show any differential expression pattern between control and study groups. ELISA results revealed a significant difference in the concentrations of DMP1, PP and DSP between control and root resorption groups. Concentration of PP and DSP in severe root resorption group was also statistically higher than in mild root resorption group.ConclusionDSP and PP could be suitable biological markers for monitoring root resorption during orthodontic treatment, since a significant difference in the level of these dentin specific proteins is detected in all groups.