Comparison between electrochemical ELISA and spectrophotometric ELISA for the detection of dentine sialophosphoprotein for root resorption.

INTRODUCTION: Root resorption is an undesirable sequela of orthodontic treatment. It is necessary to establish sensitive methods for identification of teeth at risk for resorption. The x-ray is the traditional method to diagnose root resorption, which is often at a late stage. Some researchers used enzyme-linked immunosorbent immunoassay (ELISA) combined with spectrophotometry to study some biochemical markers of root resorption. However, spectrophotometric detection often has a poor detection limit. Electrochemical detection has inherent advantages over spectrophotometric detection, which is especially suitable for small biologic samples. METHODS: We used ELISA combined with electrochemistry and ELISA combined with spectrophotometry to measure the biochemical marker dentine sialophosphoprotein in gingival crevicular fluid of orthodontic patients (treated for 8-12 months). RESULTS: Standard dentine sialophosphoprotein was used to calculate the linear regression equation. No significant difference was found between the electrochemical outcome and the spectrophotometric outcome. But the electrochemical results extended the lower end of detection from 5 pg per milliliter (by spectrophotometry) to 0.5 pg per milliliter. CONCLUSIONS: These results showed that ELISA combined with electrochemistry is a reliable and sensitive method to detect dentine sialophosphoprotein in gingival crevicular fluid.