Remineralization of Dentin in hydrogel microenvirment aided by Electrophoresis

Abstract

Objective: Remineralization of dentin collagen matrix is a challenge work, and the velocity of remineralization is too slow for its clinic application. Herein, we developed a system to quickly remineralize dentin collagen matrix with calcium and phosphate loaded hydrogel microenvirment aiding with electrophoresis. Method: The hydrogel mineralization system was constructed by 1% agarose gel containing 0.13 M CaCl2 ,1% pure gel, and 1% agarose gel containing 0.26 M Na2HPO4 in proper sequence, and the acid-etched dentin (37% H3PO4 for 2 min)was standing vertically in the junction of pure gel and Na2HPO4 loaded gel, which was connected to a electrophoresis apparatus (U=50V, I=20mA).electrophoresis for 2 hours was used as a mineralization cycle, and the all the gel systems were refreshed for the following mineralization cycles.

Result: After 6 cycles of mineralization, FTIR and XRD confirmed the mineral precipitates in the dentin slices were hydroxyapatite (HAp). SEM results showed that demineralized dentin collagen matrix were remineralized with intrafibrillar and interfibrillar HAp formation to duplicate the calcified dentin collagen matrix, the precipitates occluded the dentinal tubules, and the needle HA crystals densely packing with each other similar to enamel precipitated on remineralized dentin surface. Nanoindentation and microhardness results showed that the remineralization improved mechanical property of demineralized dentin.

Conclusion: A novel system of quick mineralization of dentin, which contained calcium and phosphate loaded agarose hydrogel microenvirment aiding with electrophoresis, was developed. The system may be a good candidate to treat dentin hypersensitivity, and other dentin defects.