Scanning electron microscopic analysis of using agarose hydrogel microenvironment to create enamel prism-like tissue on dentine surface.

ABSTRACT

OBJECTIVE: To investigate remineralisation of dentine in the hydrogel microenvironment for the management of hypersensitivity. METHODS: Human dentine slices were prepared from extracted sound human molars. They were acid-etched with phosphoric acid and put into the polyethylene tubes. The etched dentine surfaces were covered by a 2-mm-thick layer of CaCl2 agarose hydrogel. Another 2-mm-thick layer of ion-free agarose hydrogel was added on top of the CaCl2 agarose hydrogel. They were immersed into a solution containing phosphate and fluoride after gelification. The solution was replaced every 24h and the agarose hydrogels were replaced every 48h. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to evaluate the formed crystals on dentine surface after 2, 4 and 6days. SEM was used to study the mineral formed in the replaced agarose hydrogels. RESULTS: Observation under SEM showed that crystals occluded the dentinal tubules and an enamel prism-like tissue formed on the etched dentine surface. XRD and FTIR analyses confirmed the crystals were hydroxyapatite. Numerous calcium phosphate globules were found in the replaced calcium chloride agarose hydrogel. CONCLUSION: The hydrogel acts as the remineralisation microenvironment to initiate occlusion of dentinal tubules and formation of enamel prisms-like tissue on human dentine surface. CLINICAL SIGNIFICANCE: Remineralisation of dentine induced in this hydrogel microenvironment can be an alternative therapeutic technique for the management of dentine hypersensitivity.