In-vitro agarose hydrogel system for biomimetic mineralisation on demineralised dentine

Abstract

Objective: To develop an in vitro agarose hydrogel system for biomimetic mineralisation on demineralised dentine. Method: Human dentine slices were prepared from extracted sound human molars. They were polished and acid-etched with 37% phosphoric acid for 15 sec to create demineralized dentine surfaces. The slices were put into the polyethylene tubes with the demineralized dentine surface covered by a 2-mm-thick layer of calcium chloride (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 freshly prepared solution containing phosphate and fluoride and incubated at 37˚C for 6 days. The solution was replaced every 24 hours and the agarose hydrogels were replaced every 48 hours. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to evaluate the crystals formed on dentine surface. Nanoscratch test was carried out using a nano-indentor to evaluate the tribological property of the regenerated crystals with dentine.

Result: Observation under SEM showed that the crystals occluded the dentinal tubules and an enamel prism-like tissue formed on the demineralized dentine surface. XRD and FTIR analyses suggested that the crystals were hydroxyapatite. No crack was observed in the nanoscratch test.

Conclusion: In this study, an in vitro agarose hydrogel system was successfully developed to regenerate enamel prism-like tissue on demineralised dentine surface.