Hydroxyapatite regeneration of human tooth by hydrogel biomimetic mineralization model

Abstract

Objective: To describe the effects of a novel hydrogel biomimetic mineralization model in regulating hydroxyapatite regeneration on demineralized human tooth surface. Methods: Human tooth slices with enamel and dentine were prepared and polished smooth. They were demineralized by etching with 37% phosphoric acid for 15 second. The etched surface was covered by a 2mm layer of calcium chloride agarose hydrogel. Another 2mm layer of calcium ion free agarose hydrogel was added on top of the calcium chloride agarose hydrogel. They were incubated at 37oC with a freshly prepared and acidity neutral solution containing sodium hydrogen phosphate and sodium fluoride. The solution was replaced every 24 hours; and the two layer of agarose hydrogel was changed every 48 hours. Scanning electron microscopy (SEM) was used to study the crystals regenerated on enamel and dentine surface. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to evaluate the chemical structure of the crystals.

Results: SEM showed that a dense layer of crystals was regenerated and uniformly covered the enamel and dentine surface. Higher magnification (50,000x) showed that the regenerated crystals had a typical apatite hexagonal structure with the size of approximately 150nm in diameter and 2µm in length. They were orderly formed in parallel bundles. XRD and FTIR analysis suggested that the crystals were hydroxyapatite.

Conclusion: In this study, hydroxyapatite was regenerated on the demineralized enamel and dentine surface by a novel hydrogel biomimetic mineralization model.

(Supported by NSFC-RGC Grant N_HKU776/10) This abstract is based on research that was funded entirely or partially by an outside source: NSFC-RGC Grant N_HKU776/10